Publications

RAHMAN, MA, PHILLIPS, MR & TON-THAT, C 2020, 'Dopants and Impurity-Induced Defects in ZnO' in Defects in Functional Materials, WORLD SCIENTIFIC, Singapore, pp. 177-199.
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In recent years, there has been resurgent interest in ZnO due to its efficient UV emission and potential application in opto-electronic devices. The problem of self-compensating defects, especially those related to acceptor-like dopants, remains a major challenge to date. In this chapter, we provide an overview of the fundamental properties of point defects and dopants as well as their complexes in bulk crystals and nanostructures. Nominally undoped ZnO is typically n-type, which has been widely ascribed to O vacancies or Zn interstitials; however, these defect assignments are controversial as O vacancies are deep donors while Zn interstitials are highly mobile at room temperature and considered to be unstable. Accordingly, H and group III impurities have also been suggested to be responsible for the observed n-type conductivity. Although there are still many unanswered questions concerning defect-related luminescence bands in ZnO, great progress has been made in recent years to identify and characterize them using spatially resolved luminescence spectroscopies and first-principles calculations. The ubiquitous green emission has several possible origins, including O and Zn vacancies as well as Cu impurities. The properties of group I (Li, Na, and Cu), group III (Ga, Al, and In), and group V (N, P, and Sb) impurities as well as their complexes with native point defects and H are discussed, along with a concluding outlook for future research into the optical properties of ZnO.

Wang, T, Liu, Y, Su, D & Wang, G 2020, '1D and 2D Flexible Carbon Matrix Materials for Lithium–Sulfur Batteries' in Nanocarbon Electrochemistry, Wiley, USA, pp. 145-170.
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In recent years, flexible batteries along with the development of wearable electronic devices have shown significant progress. Lithium–sulfur batteries (Li–S) as a new‐generation battery system have high energy density, which is almost five times that of lithium ion batteries. In this chapter, we summarize the recent developments of flexible Li–S batteries, focusing on electrode materials, separators, and electrolytes.

Ali, S, Tahir, M, Mehboob, N, Wahab, F, J. Langford, S, Mohd Said, S, R. Sarker, M, Julai, S & Hamid Md Ali, S 2020, 'Amino Anthraquinone: Synthesis, Characterization, and Its Application as an Active Material in Environmental Sensors', Materials, vol. 13, no. 4, pp. 960-960.
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This work reports synthesis, thin film characterizations, and study of an organic semiconductor 2-aminoanthraquinone (AAq) for humidity and temperature sensing applications. The morphological and phase studies of AAq thin films are carried out by scanning electron microscope (SEM), atomic force microscope (AFM), and X-ray diffraction (XRD) analysis. To study the sensing properties of AAq, a surface type Au/AAq/Au sensor is fabricated by thermally depositing a 60 nm layer of AAq at a pressure of ~10−5 mbar on a pre-patterned gold (Au) electrodes with inter-electrode gap of 45 µm. To measure sensing capability of the Au/AAq/Au device, the variations in its capacitance and resistance are studied as a function of humidity and temperature. The Au/AAq/Au device measures and exhibits a linear change in capacitance and resistance when relative humidity (%RH) and temperature are varied. The AAq is a hydrophobic material which makes it one of the best candidates to be used as an active material in humidity sensors; on the other hand, its high melting point (575 K) is another appealing property that enables it for its potential applications in temperature sensors.

Al-Soeidat, MR, Aljarajreh, H, Khawaldeh, HA, Lu, DD-C & Zhu, J 2020, 'A Reconfigurable Three-Port DC–DC Converter for Integrated PV-Battery System', IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 8, no. 4, pp. 3423-3433.
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In this article, a new nonisolated three-port dc-dc converter to integrate a battery storage with a photovoltaic (PV) module is proposed for off-grid solar-power applications. The proposed converter can be used to integrate the PV module with a backup battery to minimize the impacts of renewable-energy intermittency and unpredictable load demand. The proposed converter is reconfigurable and able to operate as a conventional boost converter, a buck-boost converter, or a forward converter in different modes to support several power flow combinations and achieve power conditioning and regulation among the PV module, battery, and output port, simultaneously. Nevertheless, the power stage only consists of two switches, one coupled inductor, one diode, and two capacitors. A high-voltage conversion ratio is achieved by using a coupled inductor and by combining the PV module and the battery in series. Experimental results of the proposed converter operating in the steady state and during transitions between different modes are reported.

Amjadipour, M, MacLeod, J, Motta, N & Iacopi, F 2020, 'Fabrication of free-standing silicon carbide on silicon microstructures via massive silicon sublimation', Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, vol. 38, no. 6, pp. 062202-062202.
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Heteroepitaxial thin films of cubic silicon carbide (3C-SiC) on silicon offer a promising platform for leveraging the properties of SiC, such as wide bandgap, high mechanical strength, and chemical stability on a silicon substrate. Such heteroepitaxial films also attract considerable interest as pseudosubstrates for the growth of GaN as well as graphene on silicon wafers. However, due to a substantial lattice mismatch, the growth of 3C-SiC on silicon leads to a considerable amount of stresses, defects, and diffusion phenomena at the heterointerface. We show here that the extent of such interface phenomena and stresses is so large that, after patterning of the SiC, a massive sublimation of the silicon underneath the SiC/Si interface is promoted via a high-temperature anneal, either in high or medium vacuum ambient. A micrometer-thick air gap can be formed below the SiC structures, making them suspended. Hence, the described approach can be used as a straightforward methodology to form free-standing silicon carbide structures without the need for wet or anisotropic etching and could be of great interest for devices where suspended moving parts are needed, such as micro- and nanoelectromechanical systems.

Amjadipour, M, Su, D & Iacopi, F 2020, 'Cover Picture: Graphitic‐Based Solid‐State Supercapacitors: Enabling Redox Reaction by In Situ Electrochemical Treatment (Batteries & Supercaps 7/2020)', Batteries & Supercaps, vol. 3, no. 7, pp. 566-566.
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Amjadipour, M, Su, D & Iacopi, F 2020, 'Graphitic‐Based Solid‐State Supercapacitors: Enabling Redox Reaction by In Situ Electrochemical Treatment', Batteries & Supercaps, vol. 3, no. 7, pp. 587-595.
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AbstractThe quest for supercapacitors that can hold both high energy and power density is of increasing significance as the need for green and reliable energy storage devices grows, for both large‐scale and integrated systems. While supercapacitors for integrated technologies require a solid‐state approach, gel‐based electrolytes are generally not as efficient as their aqueous counterparts. Here, we demonstrate a strategy to enhance the performance of quasi‐solid‐state supercapacitors made by graphitized silicon carbide on silicon electrodes and polyvinyl alcohol (PVA)+H2SO4 gel electrolyte. The electrochemical characterization shows an increase of the specific capacitance of the cell up to 3‐fold resulting from a simple agent‐free, in situ, electrochemical treatment leading to functionalization of the graphitic electrodes. The functionalization of the electrodes simultaneously enables redox reactions, without adding any redox agent, and increases the double layer contribution to the overall capacitance. The strategy and insights offered by this work hold great promise for improving quasi‐solid‐state, miniaturized on‐chip energy storage systems, which are compatible with silicon electronics.

Amjadipour, M, Su, D & Iacopi, F 2020, 'Graphitic‐Based Solid‐State Supercapacitors: Enabling Redox Reaction by In Situ Electrochemical Treatment', Batteries & Supercaps, vol. 3, no. 7, pp. 569-569.
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AbstractInvited for this month's cover picture is the group of Integrated Nano Systems Lab (INSys Lab), part of the Centre for Clean Energy Technology, University of Technology Sydney. The cover picture illustrates an efficient in situ pathway to generate and attach oxygen functional groups to graphitic electrodes for supercapacitors by inducing hydrolysis of water molecules within the gel electrolyte. Read the full text of the Article at 10.1002/batt.201900204.

Bilokur, M, Gentle, A, Arnold, MD, Cortie, MB & Smith, GB 2020, 'Spectrally Selective Solar Absorbers based on Ta:SiO₂ Cermets for Next‐Generation Concentrated Solar–Thermal Applications', Energy Technology, vol. 8, no. 7, pp. 2000125-2000125.
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An iterative algorithm is used to design a spectrally selective thin‐film stack to provide maximum solar‐to‐thermal conversion efficiency at the very high operating temperatures associated with high solar concentrations. The resulting stack is then fabricated by magnetron sputtering and characterized. It is composed of two Ta:SiO2 layers with differing Ta nanoparticle contents on a refractory metal substrate. A SiO2 antireflecting overlayer completes the stack. Optical and microstructural characterizations indicate that the stack achieves 97.6% solar absorptance up to 900 °C. Spectral selectivity and thermal stability improve on annealing in two ways, first, due to recrystallization of Pt or Ta back reflectors which lowers room temperature thermal emittance to 0.15 from 0.18, and to 0.14 from 0.21, respectively; and second, due to alloying of substrate atoms with the Ta nanoparticles of the cermet.

Bodachivskyi, I, Kuzhiumparambil, U & Williams, DBG 2020, 'Towards furfural from the reaction of cellulosic biomass in zinc chloride hydrate solvents', Industrial Crops and Products, vol. 146, pp. 112179-112179.
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Bodachivskyi, I, Page, CJ, Kuzhiumparambil, U, Hinkley, SFR, Sims, IM & Williams, DBG 2020, 'Dissolution of Cellulose: Are Ionic Liquids Innocent or Noninnocent Solvents?', ACS Sustainable Chemistry & Engineering, vol. 8, no. 27, pp. 10142-10150.
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© 2020 American Chemical Society. Cellulose is a naturally abundant and readily accessible substrate for large scale biorefinery technologies. There has been a significant focus on ionic liquids as alternative solvents for the valorization of cellulosic substances. Ionic liquids dissolve cellulose in varying degrees, facilitating ready chemical transformations. However, there is no self-contained set of knowledge and information on the influence (or not) of the simple dissolution process on the cellulose molecule. Herein, we detail the dissolution, recovery, and characterization of cellulose in various classes of ionic solvents in a systematic study. This provides a view of the stability of cellulose in each solvent. We consider the major classes of ionic liquids commonly employed for cellulose chemistry, the dissolution in zinc chloride hydrate systems, quaternary ammonium salts, and deep eutectic solvents under varied processing conditions. We regenerate cellulosic material from the solvent and characterize the polymer employing gravimetric analysis, IR spectroscopy, and size exclusion chromatography. Surprisingly, most ionic liquids employed caused reduction in the MW of the cellulose.

Bramerdorfer, G, Cavagnino, A, Choi, S, Lei, G, Lowther, D, Stipetic, S, Sykulski, J, Zhang, Y & Zhu, JG 2020, 'Guest Editorial: Robust Design and Analysis of Electric Machines and Drives', IEEE Transactions on Energy Conversion, vol. 35, no. 4, pp. 1995-1996.
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Chen, H, Li, G, Allam, VSRR, Wang, B, Chan, YL, Scarfo, C, Ueland, M, Shimmon, R, Fu, S, Foster, P & Oliver, BG 2020, 'Evidence from a mouse model on the dangers of thirdhand electronic cigarette exposure during early life', ERJ Open Research, vol. 6, no. 2, pp. 00022-2020.
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Thirdhand exposure to e-cigarette residue is likely to have harmful effects in children http://bit.ly/38a2umw.

Chen, J, Wei, L, Mahmood, A, Pei, Z, Zhou, Z, Chen, X & Chen, Y 2020, 'Prussian blue, its analogues and their derived materials for electrochemical energy storage and conversion', Energy Storage Materials, vol. 25, pp. 585-612.
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Chen, X, Chen, Y, Luo, X, Guo, H, Wang, N, Su, D, Zhang, C, Liu, T, Wang, G & Cui, L 2020, 'Polyaniline engineering defect-induced nitrogen doped carbon-supported Co3O4 hybrid composite as a high-efficiency electrocatalyst for oxygen evolution reaction', Applied Surface Science, vol. 526, pp. 146626-146626.
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© 2020 Elsevier B.V. The development of earth-abundance electrocatalyst with high performance for oxygen evolution reaction (OER) is of paramount importance in sustainable water splitting. Herein, the novel defect-induced nitrogen-doped carbon-supported Co3O4 nanoparticles is successfully fabricated as OER electrocatalyst (denoted as Co3O4/CN HNPs) through a wetness-impregnation treatment of Co/polyaniline (PANI) followed by a thermal annealing. This advanced architecture of Co3O4/CN HNPs can not only improve its conductivity and electrocatalytically active sites but also generate a large number of oxygen-vacancy defects and crystal defects, which effectively exert the preponderance in facilitating interfacial electronic transfer and optimizing the adsorption energy for intermediates, thus imparting the extraordinary activities in catalyzing OER. In addition, there are evidences demonstrating the formation of C-N coordination bonds through the strong interaction of the interconnected interface and the generation of pyridinic-N species after the annealing treatment, which enables the structural stability to get further strengthened and accelerates oxygen releasing for reduction of OER overpotential, respectively. Benefiting from the above desirable properties, the Co3O4/CN HNPs affords a lower overpotential of 290 mV at a current density of 10 mA cm−2 as compared to those of pure Co3O4 and PANI, outperforming commercial IrO2 and the representative Co3O4-based OER electrocatalysts as recently reported. Moreover, the Co3O4/CN HNPs also exhibits long durability with negligible activity degeneration at a current density of 10 mA cm−2 for 20 h. ̵.

Chen, X, Chen, Y, Shen, Z, Song, C, Ji, P, Wang, N, Su, D, Wang, Y, Wang, G & Cui, L 2020, 'Self-crosslinkable polyaniline with coordinated stabilized CoOOH nanosheets as a high-efficiency electrocatalyst for oxygen evolution reaction', Applied Surface Science, vol. 529, pp. 147173-147173.
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© 2020 Polyaniline (PANI)-based composite materials have shown to be promising candidates for oxygen evolution reaction (OER) electrocatalysts because of their non-ignorable merits of conductivity, flexibility, durability and environmental friendly. Herein, we develop a facile strategy to realize in-situ assembly of CoOOH nanosheets into the PANI network, which is denoted as Co/PANI HNSs for OER performance. The nitrogen species derived from PANI building blocks can work as bridging sites to preferentially coordinate with Co metal ions, which impart coupling effects between CoOOH nanosheets and PANI as well as the structure stability. Besides the Co-N coordination, the occurred electron delocalization between Co d-orbitals and PANI π-conjugated ligands can also modulate the electronic structural states of Co/PANI HNSs, enabling the efficient interfacial electron transfer from CoOOH to PANI. In addition, the Co/PANI HNSs possesses a hierarchical porous with both structure of mesopores and macropores that allows electrolyte to be more efficiently transported to the highly oxidative active sites, resulting in fast reaction kinetics. In recognition of these advanced structural characteristics, the Co/PANI HNSs electrocatalyst can give a low overpotential of 291 mV at an anodic current density of 10 mA cm−2 and a small Tafel slope of 54 mV dec−1 in 1 M KOH electrolyte as well as a good durability.

Chen, Y, Gao, X, Su, D, Wang, C & Wang, G 2020, 'Accelerating Redox Kinetics of Lithium-Sulfur Batteries', Trends in Chemistry, vol. 2, no. 11, pp. 1020-1033.
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Lithium-sulfur (Li-S) batteries exhibit great promise for next-generation energy storage due to their high theoretical energy density and low cost. However, their practical application is largely hindered by the shuttle effect. Although previous studies on the adsorption of lithium polysulfides (LiPSs) have achieved significant progress, simple adsorption cannot fundamentally eliminate the shuttle effect. Physical and chemical confinement are useful to anchor LiPSs to some extent, but these are not effective for utilizing the blocked intermediates. Accordingly, accelerating polysulfide redox kinetics is crucial to radically mitigate the shuttle effect and increase sulfur utilization. Herein, recent advances in catalysts for boosting redox kinetics of Li-S batteries are reviewed. We also provide prospects on the design of more efficient catalysts for Li-S batteries.

Chen, Z, Ibrahim, I, Hao, D, Liu, X, Wu, L, Wei, W, Su, D & Ni, B-J 2020, 'Controllable design of nanoworm-like nickel sulfides for efficient electrochemical water splitting in alkaline media', Materials Today Energy, vol. 18, pp. 100573-100573.
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© 2020 Elsevier Ltd Developing cost-effective electrocatalysts for electrochemical water splitting (EWS) is appealing and challenging for sustainable water electrolysis. Currently, nickel sulfides are considered as promising candidates for EWS due to their low cost and high catalytic activity. However, the facile design of nickel sulfides with high catalytic performance is still highly demanded. In this study, we have developed a one-step solvothermal strategy to construct nickel sulfides as efficient water splitting catalysts. By taking advantage of the small size, abundant active sites, large electrochemical surface area, and good conductivity, the nanoworm-like nickel sulfides (NiS-NW/Ni foam [NF]) exhibit better oxygen evolution reaction performance (a low overpotential of 279 mV to achieve 100 mA cm−2, Tafel slope of 38.44 mV dce−1) than the nanoplate-like analogs, as well as most of reported nickel sulfide–based electrocatalysts. In addition, the NiS-NW/NF directly used as bifunctional electrodes for overall water splitting requires a low voltage of 1.563 V to attain a current density of 10 mA cm−2 with good long-term durability. This work provides a facile strategy for the design of efficient nickel sulfide-based electrocatalysts for energy conversion applications.

Cortie, MB, Arnold, MD & Keast, VJ 2020, 'The Quest for Zero Loss: Unconventional Materials for Plasmonics', Advanced Materials, vol. 32, no. 18, pp. 1904532-1904532.
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AbstractThere has been an ongoing quest to optimize the materials used to build plasmonic devices: first the elements were investigated, then alloys and intermetallic compounds, later semiconductors were considered, and, most recently, there has been interest in using more exotic materials such as topological insulators and conducting oxides. The quality of the plasmon resonances in these materials is closely correlated with their structure and properties. In general gold and silver are the most commonly specified materials for these applications but they do have weaknesses. Here, it is shown how, in specific circumstances, the selection of certain other materials might be more useful. Candidate alternatives include TixN, VO2, Al, Cu, Al‐doped ZnO, and Cu–Al alloys. The relative merits of these choices and the many pitfalls and subtle problems that arise are discussed, and a frank perspective on the field is provided.

Cox, RP, Sandanayake, S, Langford, SJ & Bell, TDM 2020, 'Electron Transfer in a Naphthalene Diimide System Studied by Single-Molecule Delayed Fluorescence', Australian Journal of Chemistry, vol. 73, no. 8, pp. 699-699.
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Electron transfer (ET) is a key chemical reaction in nature and has been extensively studied in bulk systems, but remains challenging to investigate at the single-molecule level. A previously reported naphthalene diimide (NDI)-based system (Higginbotham et al., Chem. Commun. 2013, 49, 5061–5063) displays delayed fluorescence with good quantum yield (~0.5) and long-lived (nanoseconds) prompt and delayed fluorescence lifetimes, providing an opportunity to interrogate the underlying ET processes in single molecules. Time-resolved single-molecule fluorescence measurements enabled forward and reverse ET rate constants to be calculated for 45 individual molecules embedded in poly(methylmethacrylate) (PMMA) film. Interpretation of the results within the framework of Marcus–Hush theory for ET demonstrates that variation in both the electronic coupling and the driving force for ET is occurring from molecule to molecule within the PMMA film and over time for individual molecules.

Diao, K, Sun, X, Lei, G, Guo, Y & Zhu, J 2020, 'Multiobjective System Level Optimization Method for Switched Reluctance Motor Drive Systems Using Finite-Element Model', IEEE Transactions on Industrial Electronics, vol. 67, no. 12, pp. 10055-10064.
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© 1982-2012 IEEE. This article presents a novel multiobjective system level optimization method to achieve the best performance of switched reluctance motor (SRM) drive systems. First, the multiobjective optimization problem for the SRM drive systems is defined. Then, all parameters of the drive systems, including the motor level and control level, are divided into three subspaces according to their influences on the objectives. Finally, the optimization of each subspace is performed sequentially until a convergence criterion is met. Then, the optimal solution can be chosen from the Pareto solutions according to a selection criterion. Meanwhile, the sensitivity analysis, the approximate models, and the genetic algorithm are employed to reduce the computation cost. To verify the effectiveness of the proposed method, an SRM drive system with a segmented-rotor SRM (SSRM) and the angle position control method is investigated. This is a high-dimensional system level optimization problem with ten parameters. The finite-element model (FEM) results are verified by the experiment results. The optimal solution has been listed and verified by the FEM. From the discussion, it can be found that the proposed optimization method is efficient and optimized SSRM drive system has high efficiency and low torque ripple.

Dong, L, Yang, W, Yang, W, Tian, H, Huang, Y, Wang, X, Xu, C, Wang, C, Kang, F & Wang, G 2020, 'Flexible and conductive scaffold-stabilized zinc metal anodes for ultralong-life zinc-ion batteries and zinc-ion hybrid capacitors', Chemical Engineering Journal, vol. 384, pp. 123355-123355.
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© 2019 Elsevier B.V. The merits of zinc metal anodes such as high chemical stability, low cost and ultrahigh volumetric capacity endow Zn based batteries/hybrid capacitors with great potential applications for electronic products. However, unstable stripping/plating of zinc anodes tends to cause the formation of protuberances/dendrites and side reactions such as water decomposition on anode surfaces, eventually leading to the failure of Zn based electrochemical energy storage devices. Herein, we report the fabrication of free-standing, highly flexible and conductive carbon nanotube (CNT)/paper scaffolds to stabilize zinc metal anodes. The free-standing CNT scaffolds only need to be placed between zinc anodes and separators when assembling zinc anode-based batteries/hybrid capacitors. On the surface of the zinc electrode, the scaffolds’ porous skeleton mechanically regulates Zn2+ deposition sites and their conductive CNT networks maintain a stable electric field during Zn stripping/plating processes, thus retarding the formation of protuberances/dendrites and the occurrence of side reactions. The scaffold-stabilized zinc anodes displayed small polarization voltages, a long cycling life over 1800 h and superior capability for fast charging-discharging. In addition, benefiting from the high electrochemical stability and reversibility of the scaffold-stabilized zinc anodes, zinc-ion batteries/hybrid capacitors with ultralong cycle lives were successfully constructed. This work provides a scalable approach to stabilize zinc metal anodes for long-life zinc-ion batteries and zinc-ion hybrid capacitors.

Dou, Y, Li, Y, Zhang, C, Yue, S & Zhu, J 2020, 'Effects of Uniaxial Stress Along Different Directions on Alternating Magnetic Properties of Silicon Steel Sheets', IEEE Transactions on Magnetics, vol. 56, no. 3, pp. 1-4.
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Du, G, Huang, N, He, H, Lei, G & Zhu, J 2020, 'Parameter Design for a High-Speed Permanent Magnet Machine Under Multiphysics Constraints', IEEE Transactions on Energy Conversion, vol. 35, no. 4, pp. 2025-2035.
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Du, G, Xu, W, Zhu, J & Huang, N 2020, 'Effects of Design Parameters on the Multiphysics Performance of High-Speed Permanent Magnet Machines', IEEE Transactions on Industrial Electronics, vol. 67, no. 5, pp. 3472-3483.
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© 1982-2012 IEEE. In the design of high-speed permanent magnet machines (HSPMMs), comprehensive effects of design parameters on the various properties of electromagnetic loss, rotor stress, rotor critical speed, and temperature distribution must be analyzed to obtain the optimal design. The aim of this paper is to examine the effects of design parameters, such as the pole number, stator slots number, number of conductors per slot, permanent magnet (PM) thickness, PM pole arc coefficient, air gap length, rotor diameter, core length, and sleeve thickness, on multiphysics performance based on a high-power HSPMM. A reasonable design is determined according to the abovementioned analysis that satisfies all specified multiphysics constraints. The theoretical results are confirmed by the experimental results on a prototype in terms of electromagnetic, mechanical, and thermal characteristics such as back electromotive force, no-load loss, full-load current, overspeed experiment, and temperature distribution.

Du, G, Xu, W, Zhu, J & Huang, N 2020, 'Power Loss and Thermal Analysis for High-Power High-Speed Permanent Magnet Machines', IEEE Transactions on Industrial Electronics, vol. 67, no. 4, pp. 2722-2733.
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© 1982-2012 IEEE. For high-speed permanent magnet machines (HSPMMs), the permanent magnet (PM) is more likely to suffer irreversible demagnetization because the heat dissipation is serious in the HSPMMs, especially for the high-power machines. This paper focuses on the comprehensive research results on the power loss and thermal characteristic for a high-power HSPMM. First, the power loss at the rated load is investigated by finite-element analysis. Then, the temperature distribution of four cooling schemes is compared by the electromagnetic-thermal iteration calculation. The effect of different parameters on thermal behavior is obtained to reduce rotor temperature, which includes an examination of the axial flow duct, cooling medium, sleeve thickness, and sleeve thermal conductivity. Finally, an improved loss separation method is employed to obtain the loss distribution from the measured total loss, and the comprehensive experiments are implemented based on one HSPMM prototype (800 kW, 15 000 rpm) to verify the related theoretical analysis.

Fan, L, Zhang, Y, Guo, Z, Sun, B, Tian, D, Feng, Y, Zhang, N & Sun, K 2020, 'Hierarchical Mn₃O₄ Anchored on 3D Graphene Aerogels via C−O−Mn Linkage with Superior Electrochemical Performance for Flexible Asymmetric Supercapacitor', Chemistry – A European Journal, vol. 26, no. 42, pp. 9314-9318.
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AbstractFlexible asymmetric supercapacitors are more appealing in flexible electronics because of high power density, wide cell voltage, and higher energy density than symmetric supercapacitors in aqueous electrolyte. In virtues of excellent conductivity, rich porous structure and interconnected honeycomb structure, three dimensional graphene aerogels show great potential as electrode in asymmetric supercapacitors. However, graphene aerogels are rarely used in flexible asymmetric supercapacitors because of easily re‐stacking of graphene sheets, resulting in low electrochemical activity. Herein, flower‐like hierarchical Mn3O4 and carbon nanohorns are incorporated into three dimensional graphene aerogels to restrain the stack of graphene sheets, and are applied as the positive and negative electrode for asymmetric supercapacitors devices, respectively. Besides, a strong chemical coupling between Mn3O4 and graphene via the C‐O‐Mn linkage is constructed and can provide a good electron‐transport pathway during cycles. Consequently, the asymmetric supercapacitor device shows high rate cycle stability (87.8 % after 5000 cycles) and achieves a high energy density of 17.4 μWh cm−2 with power density of 14.1 mW cm−2 (156.7 mW cm−3) at 1.4 V.

Farrok, O, Islam, MR, Muttaqi, KM, Sutanto, D & Zhu, J 2020, 'Design and Optimization of a Novel Dual-Port Linear Generator for Oceanic Wave Energy Conversion', IEEE Transactions on Industrial Electronics, vol. 67, no. 5, pp. 3409-3418.
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Feng, Z, Lin, S, McDonagh, A & Yu, C 2020, 'Natural Hydrogels Applied in Photodynamic Therapy', Current Medicinal Chemistry, vol. 27, no. 16, pp. 2681-2703.
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Natural hydrogels are three-dimensional (3D) water-retaining materials with a skeleton consistingof natural polymers, their derivatives or mixtures. Natural hydrogels can provide sustained orcontrolled drug release and possess some unique properties of natural polymers, such as biodegradability,biocompatibility and some additional functions, such as CD44 targeting of hyaluronic acid. Naturalhydrogels can be used with photosensitizers (PSs) in photodynamic therapy (PDT) to increase the rangeof applications. In the current review, the pertinent design variables are discussed along with a descriptionof the categories of natural hydrogels available for PDT.

Fiedler, S, Lee Cheong Lem, LO, Ton-That, C & Phillips, MR 2020, 'The role of surface depletion layer effects on the enhancement of the UV emission in ZnO induced by a nanostructured Al surface coating', Applied Surface Science, vol. 504, pp. 144409-144409.
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© 2019 The UV enhancement of Al-coated ZnO single crystals with a wide range of carrier densities is systematically studied using depth-resolved cathodoluminescence and photoluminescence as well as valence band X-ray photoemission spectroscopy (VB-XPS). An up to 17-fold enhanced PL UV emission for Al-coated ZnO with the highest carrier density was measured, which falls to a 12-fold increase for the lowest carrier density. Depth-resolved cathodoluminescence measurements confirm that the enhancement is strongest near the Al-ZnO interface consistent with an increased UV emission due to an exciton-localized surface plasmon coupling mechanism. Correlative cathodoluminescence, photoluminescence and VB-XPS studies reveal that a number of additional effects related to the presence of the Al surface coating also contribute to the UV enhancement factor. These include increased UV enhancement due to the formation of a surface depletion layer induced by the Al coating, which also passivates competitive non-radiative surface recombination channels found in uncoated ZnO. Significantly, it was established that the magnitude of the emission enhancement factor can be raised in a controlled way by reducing the thickness of the depletion layer by increasing the carrier density. The contribution of these effects collectively provides an explanation for the large span of enhancement factors reported in the literature.

Fiedler, S, Lee Cheong Lem, LO, Ton-That, C, Hoffmann, A & Phillips, MR 2020, 'Enhancement of the UV emission from gold/ZnO nanorods exhibiting no green luminescence', Optical Materials Express, vol. 10, no. 6, pp. 1476-1476.
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Large reflection losses at interfaces in light-emitting semiconductor devices cause a significant reduction in their light emission and energy efficiencies. Metal nanoparticle (NP) surface coatings have been demonstrated to increase the light extraction efficiency from planar high refractive index semiconductor surfaces. This emission enhancement in Au NP-coated ZnO is widely attributed to involvement of a green (∼ 2.5 eV) deep level ZnO defect exciting localized surface plasmons in the NPs. In this work, we achieve a 6 times enhancement of the ultra-violet excitonic emission in ZnO nanorods coated with 5 nm Au NPs without the aid of ZnO defects. Cathodoluminescence (CL) and photoluminescence (PL) spectroscopy revealed that the increased UV emission is due to the formation of an additional fast excitonic relaxation pathway. Concurrent CL-PL measurements ruled out the presence of charge transfer mechanism in the emission enhancement process. While time-resolved PL confirmed the existence of a new excitonic recombination channel that is attributed to exciton relaxation via the excitation of rapid non-radiative Au interband transitions that increases the UV spontaneous emission rate. Our results establish that ZnO defect levels ∼ 2.5 eV are not required to facilitate Au NP induced enhancement of the ZnO UV emission.

Fiedler, S, Lem, LOLC, Ton-That, C, Schleuning, M, Hoffmann, A & Phillips, MR 2020, 'Correlative Study of Enhanced Excitonic Emission in ZnO Coated with Al Nanoparticles using Electron and Laser Excitation', Scientific Reports, vol. 10, no. 1, p. 2553.
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AbstractRecently, metal nanoparticle surface coatings have been found to significantly enhance the ultra-violet luminescence intensity from ZnO, providing a viable means to mitigate optical losses and improve LED performance. Although there is general agreement that resonantly excited Localized Surface Plasmons (LSPs) in metal nanoparticles can directly couple to excitons in the semiconductor increasing their spontaneous emission rate, the exact mechanisms involved in this phenomenon are currently not fully understood. In this work, LSP-exciton coupling in bulk and nanostructured ZnO coated with a 2 nm Al nanoparticle layer is investigated using correlative photoluminescence and depth-resolved cathodoluminescence and time-resolved photoluminescence spectroscopy. Temperature-resolved cathodoluminescence and photoluminescence measurements from 10 K to 250 K show free exciton (FX) emission enhancement factors up to 12x at 80 K, and reveal that the FX couple more efficiently to the LSPs compared to the localized donor-bound excitons. A strong polarization dependence between the LSPs and FX is observed where FX transitions are more strongly enhanced when polarized in the same direction as the electric field of the incident excitation, which is different for laser and electron beam sources. This result indicates that selective enhancement of the excitonic emission peaks in the ZnO coated with Al nanoparticles can be achieved by choosing the appropriate ZnO substrate orientation.

Gao, P, Huang, Z & Yu, H 2020, 'Exploration of the Dehydrogenation Pathways of Ammonia Diborane and Diammoniate of Diborane by Molecular Dynamics Simulations Using Reactive Force Fields', The Journal of Physical Chemistry A, vol. 124, no. 9, pp. 1698-1704.
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Ammonium aminodiboranate (AADB) and diammoniate of diborane (DADB) are two isomers of ammonia borane (AB), which have been intensively studied for hydrogen storage. Their high hydrogen contents give them the high potential to serve as hydrogen storage materials. To explore their dehydrogenation pathways, molecular dynamics (MD) simulations with a reactive force field (ReaxFF) were applied. Temperature ramping simulations of their thermolysis were carried out. For AADB, at low temperatures, its hydrogen release can be realized mainly via intermolecular dehydrogenations. As the temperature of the simulated system increases, the formations of B-N bonds begin to occur. In the case of DADB, we found that this molecule could release hydrogen at a lower temperature with the cleavage of the B-N bond. The compositional analysis of the simulated systems was also conducted to monitor the potential intermediates along their dehydrogenation pathways. Our current work provides a detailed picture of the initial dehydrogenation steps of AADB and DADB and highlights the difference in their respective dehydrogenation processes.

Goikolea, E, Palomares, V, Wang, S, de Larramendi, IR, Guo, X, Wang, G & Rojo, T 2020, 'Na‐Ion Batteries—Approaching Old and New Challenges', Advanced Energy Materials, vol. 10, no. 44, pp. 2002055-2002055.
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AbstractThe last 10 years established the beginning of a post‐lithium era in the field of energy storage, with the renaissance of Na‐ion batteries (NIBs) as alternative for Li‐based systems. The development of this technology has required intense work in materials research in order to produce and optimize anodes, cathodes, and electrolytes for NIBs. The strong and weak points of the main families of compounds for each battery component are analyzed in this progress report. Taking into account the achievements made in materials for NIBs, the industrial scene is analyzed through the existing prototypes and commercial cells and also from an economical viewpoint. In this scenario, where Na‐ion technology seems to be ready for a coming second generation, the use of Na can be extended to almost the whole spectrum of electrochemical energy storage systems: the new room temperature Na–S systems, high‐energy Na–air technology, or high‐power Na‐based hybrid supercapacitors. Thus, the degree of development of NIBs, together with the promising performance of newer Na‐based energy storage systems, makes Na the key to the coming commercial post‐lithium systems.

Guo, X, Gao, H & Wang, G 2020, 'A Robust Transition-Metal Sulfide Anode Material Enabled by Truss Structures', Chem, vol. 6, no. 2, pp. 334-336.
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The practical application of high-capacity transition-metal sulfide anodes has been hampered by the poor rate capability and cycling performance. As recently reported in Matter, Yang and co-workers have developed a robust micro-truss structural Cu 1.81S material with excellent mechanical strength for high-performance sodium-ion batteries.

Guo, Z, Zhao, S, Li, T, Su, D, Guo, S & Wang, G 2020, 'Recent Advances in Rechargeable Magnesium‐Based Batteries for High‐Efficiency Energy Storage', Advanced Energy Materials, vol. 10, no. 21, pp. 1903591-1903591.
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AbstractBenefiting from higher volumetric capacity, environmental friendliness and metallic dendrite‐free magnesium (Mg) anodes, rechargeable magnesium batteries (RMBs) are of great importance to the development of energy storage technology beyond lithium‐ion batteries (LIBs). However, their practical applications are still limited by the absence of suitable electrode materials, the sluggish kinetics of Mg2+ insertion/extraction and incompatibilities between electrodes and electrolytes. Herein, a systematic and insightful review of recent advances in RMBs, including intercalation‐based cathode materials and conversion reaction‐based compounds is presented. The relationship between microstructures with their electrochemical performances is comprehensively elucidated. In particular, anode materials are discussed beyond metallic Mg for RMBs. Furthermore, other Mg‐based battery systems are also summarized, including Mg–air batteries, Mg–sulfur batteries, and Mg–iodine batteries. This review provides a comprehensive understanding of Mg‐based energy storage technology and could offer new strategies for designing high‐performance rechargeable magnesium batteries.

Han, R, Liu, F, Wang, X, Huang, M, Li, W, Yamauchi, Y, Sun, X & Huang, Z 2020, 'Functionalised hexagonal boron nitride for energy conversion and storage', Journal of Materials Chemistry A, vol. 8, no. 29, pp. 14384-14399.
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This review highlights recent research advances in functionalised hexagonal boron nitride for energy conversion and storage applications.

He, S, Huang, D, Feng, X, Deng, J, Li, J & Zhu, J 2020, 'Transient potential distribution on transformer winding considering the effect of core lamination stack', AIP Advances, vol. 10, no. 1, pp. 015024-015024.
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The potential distribution of windings under impulse voltage is very important for the design of transformer inter-turn insulation especially for large capacity transformers such as ultra-high voltage direct current (UHVDC) converter transformer. Quite a lot of equivalent circuit models for transformer winding have been proposed for the potential distribution calculation assuming that the influence of magnetic core is negligible at frequencies higher than 10 kHz. However, lightning impulse or VFTO waveforms usually contain abundant frequency components higher than 10 kHz. At above situations the magnetic core plays an important role during the transient procedure. To obtain a more comprehensive model and also to provide a more accurate potential distribution of transformer winding, in this paper, a wide frequency magnetic properties of silicon steel sheet were measured and the relationship between relative permeability of lamination stack and frequency is studied and implemented in the calculation of frequency-dependent parameters such as resistance, self- and mutual-inductances. Then the equivalent circuit model of UHVDC converter transformer is established considering the properties of core lamination stack. Coding the program in MATLAB to solve the matrix equation and the potential distribution properties are extracted from the calculation results under lightning situation. The inter-turn potential distribution is also analyzed and the results may provide more accurate information for transformer inter-turn insulation design.

Hong, L, Ju, S, Yang, Y, Zheng, J, Xia, G, Huang, Z, Liu, X & Yu, X 2020, 'Hollow-shell structured porous CoSe₂ microspheres encapsulated by MXene nanosheets for advanced lithium storage', Sustainable Energy & Fuels, vol. 4, no. 5, pp. 2352-2362.
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Cobalt diselenide (CoSe₂), a representative transition-metal chalcogenide (TMC), is attracting intensive interest as an anode material for lithium ion batteries (LIBs), in view of its high specific capacity based on the conversion reaction mechanism.

Huang, W, Hua, W, Chen, F & Zhu, J 2020, 'Enhanced Model Predictive Torque Control of Fault-Tolerant Five-Phase Permanent Magnet Synchronous Motor With Harmonic Restraint and Voltage Preselection', IEEE Transactions on Industrial Electronics, vol. 67, no. 8, pp. 6259-6269.
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Huang, W, Hua, W, Chen, F, Hu, M & Zhu, J 2020, 'Model Predictive Torque Control With SVM for Five-Phase PMSM Under Open-Circuit Fault Condition', IEEE Transactions on Power Electronics, vol. 35, no. 5, pp. 5531-5540.
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Huang, Z, Wang, S, Dewhurst, RD, Ignat'ev, NV, Finze, M & Braunschweig, H 2020, 'Boron: Its Role in Energy‐Related Processes and Applications', Angewandte Chemie International Edition, vol. 59, no. 23, pp. 8800-8816.
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AbstractBoron's unique position in the Periodic Table, that is, at the apex of the line separating metals and nonmetals, makes it highly versatile in chemical reactions and applications. Contemporary demand for renewable and clean energy as well as energy‐efficient products has seen boron playing key roles in energy‐related research, such as 1) activating and synthesizing energy‐rich small molecules, 2) storing chemical and electrical energy, and 3) converting electrical energy into light. These applications are fundamentally associated with boron's unique characteristics, such as its electron‐deficiency and the availability of an unoccupied p orbital, which allow the formation of a myriad of compounds with a wide range of chemical and physical properties. For example, boron's ability to achieve a full octet of electrons with four covalent bonds and a negative charge has led to the synthesis of a wide variety of borate anions of high chemical and electrochemical stability—in particular, weakly coordinating anions. This Review summarizes recent advances in the study of boron compounds for energy‐related processes and applications.

Hundal, AK, Agarwal, A, Jameel, MA, Ali, S, Chen, J-Y, Kaur, N, Jones, L, Li, J-L, Langford, SJ & Gupta, A 2020, 'Impact of self-assembly on the photovoltaic properties of a small molecule oligothiophene donor', Solar Energy, vol. 195, pp. 223-229.
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Huynh, TT, Chikoidze, E, Irvine, CP, Zakria, M, Dumont, Y, Teherani, FH, Sandana, EV, Bove, P, Rogers, DJ, Phillips, MR & Ton-That, C 2020, 'Red luminescence in H-doped β−Ga2O3', Physical Review Materials, vol. 4, no. 8.
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© 2020 American Physical Society. The effects of hydrogen incorporation into β-Ga2O3 thin films have been investigated by chemical, electrical, and optical characterization techniques. Hydrogen incorporation was achieved by remote plasma doping without any structural alterations of the film; however, x-ray photoemission reveals major changes in the oxygen chemical environment. Depth-resolved cathodoluminescence (CL) reveals that the near-surface region of the H-doped Ga2O3 film exhibits a distinct red luminescence (RL) band at 1.9 eV. The emergence of the H-related RL band is accompanied by an enhancement in the electrical conductivity of the film by an order of magnitude. Temperature-resolved CL points to the formation of abundant H-related donors with a binding energy of 28±4meV. The RL emission is attributed to shallow donor-deep acceptor pair recombination, where the acceptor is a VGa-H complex and the shallow donor is interstitial H. The binding energy of the VGa-H complex, based on our experimental considerations, is consistent with the computational results by Varley, [J. Phys.: Condens. Matter 23, 334212 (2011)]10.1088/0953-8984/23/33/334212.

Jaumaux, P, Liu, Q, Zhou, D, Xu, X, Wang, T, Wang, Y, Kang, F, Li, B & Wang, G 2020, 'Deep‐Eutectic‐Solvent‐Based Self‐Healing Polymer Electrolyte for Safe and Long‐Life Lithium‐Metal Batteries', Angewandte Chemie, vol. 59, no. 23, pp. 9134-9142.
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Jin, J, Zhang, R, Lin, Z, Guo, Y, Zhu, J, Chen, X & Shen, B 2020, 'Modelling analysis of periodically arranged high-temperature superconducting tapes', Physica C: Superconductivity and its Applications, vol. 578, pp. 1353747-1353747.
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Jin, P, Tian, Y, Lu, Y, Guo, Y, Lei, G & Zhu, J 2020, '3-D Analytical Magnetic Field Analysis of the Eddy Current Coupling With Halbach Magnets', IEEE Transactions on Magnetics, vol. 56, no. 1, pp. 1-4.
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Khan, K, Tareen, AK, Aslam, M, Mahmood, A, khan, Q, Zhang, Y, Ouyang, Z, Guo, Z & Zhang, H 2020, 'Going green with batteries and supercapacitor: Two dimensional materials and their nanocomposites based energy storage applications', Progress in Solid State Chemistry, vol. 58, pp. 100254-100254.
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Khan, K, Tareen, AK, Aslam, M, Sagar, RUR, Zhang, B, Huang, W, Mahmood, A, Mahmood, N, Khan, K, Zhang, H & Guo, Z 2020, 'Recent Progress, Challenges, and Prospects in Two-Dimensional Photo-Catalyst Materials and Environmental Remediation', Nano-Micro Letters, vol. 12, no. 1.
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AbstractThe successful photo-catalyst library gives significant information on feature that affects photo-catalytic performance and proposes new materials. Competency is considerably significant to form multi-functional photo-catalysts with flexible characteristics. Since recently, two-dimensional materials (2DMs) gained much attention from researchers, due to their unique thickness-dependent uses, mainly for photo-catalytic, outstanding chemical and physical properties. Photo-catalytic water splitting and hydrogen (H2) evolution by plentiful compounds as electron (e−) donors is estimated to participate in constructing clean method for solar H2-formation. Heterogeneous photo-catalysis received much research attention caused by their applications to tackle numerous energy and environmental issues. This broad review explains progress regarding 2DMs, significance in structure, and catalytic results. We will discuss in detail current progresses of approaches for adjusting 2DMs-based photo-catalysts to assess their photo-activity including doping, hetero-structure scheme, and functional formation assembly. Suggested plans, e.g., doping and sensitization of semiconducting 2DMs, increasing electrical conductance, improving catalytic active sites, strengthening interface coupling in semiconductors (SCs) 2DMs, forming nano-structures, building multi-junction nano-composites, increasing photo-stability of SCs, and using combined results of adapted approaches, are summed up. Hence, to further improve 2DMs photo-catalyst properties, hetero-structure design-based 2DMs’ photo-catalyst basic mechanism is also reviewed.

Khan, SA, Guo, Y, Siwakoti, YP, Lu, DD-C & Zhu, J 2020, 'A Disturbance Rejection-Based Control Strategy for Five-Level T-Type Hybrid Power Converters With Ripple Voltage Estimation Capability', IEEE Transactions on Industrial Electronics, vol. 67, no. 9, pp. 7364-7374.
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© 1982-2012 IEEE. This article proposes a robust control strategy for five-level T-type (5L-T) hybrid power converters to achieve superior dynamic performance for effectively regulating the dc-bus voltage under external disturbances and generating high-quality grid current at the same time. A new filter-less dc-bus ripple voltage estimation method and a simple technique to remove this ripple component from the measured dc-bus voltage of a single-phase converter are developed. A sliding-mode control (SMC) incorporated with an extended-state observer (ESO) is employed for the outer voltage control loop, and to dynamically calculate the input (i.e., the active power reference) for the inner current-tracking controller. The proposed SMC-ESO approach presents a high disturbance rejection capability and robustness against the dc-bus load variation, and thus, significantly improves the dynamic and steady-state performance during system uncertainties. Moreover, a finite control set-model predictive control algorithm is derived as the inner current controller to track their references while balancing the dc-bus capacitor voltages. The effectiveness of the proposed controller is demonstrated and verified through measurement results.

Komalla, V, Sheikholeslami, B, Li, G, Bokshi, B, Chan, YL, Ung, A, Gregory Oliver, B, Chen, H & Haghi, M 2020, 'Impact of A Cargo-Less Liposomal Formulation on Dietary Obesity-Related Metabolic Disorders in Mice', International Journal of Molecular Sciences, vol. 21, no. 20, pp. 7640-7640.
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Current therapeutic options for obesity often require pharmacological intervention with dietary restrictions. Obesity is associated with underlying inflammation due to increased tissue macrophage infiltration, and recent evidence shows that inflammation can drive obesity, creating a feed forward mechanism. Therefore, targeting obesity-induced macrophage infiltration may be an effective way of treating obesity. Here, we developed cargo-less liposomes (UTS-001) using 1,2-dioleoyl-sn-glycero-3-phosphocholine, DOPC (synthetic phosphatidylcholine) as a single-agent to manage weight gain and related glucose disorders due to high fat diet (HFD) consumption in mice. UTS-001 displayed potent immunomodulatory properties, including reducing resident macrophage number in both fat and liver, downregulating liver markers involved in gluconeogenesis, and increasing marker involved in thermogenesis. As a result, UTS-001 significantly enhanced systemic glucose tolerance in vivo and insulin-stimulated cellular glucose uptake in vitro, as well as reducing fat accumulation upon ad libitum HFD consumption in mice. UTS-001 targets tissue residence macrophages to suppress tissue inflammation during HFD-induced obesity, resulting in improved weight control and glucose metabolism. Thus, UTS-001 represents a promising therapeutic strategy for body weight management and glycaemic control.

Leong, HS, Philp, M, Simone, M, Witting, PK & Fu, S 2020, 'Synthetic Cathinones Induce Cell Death in Dopaminergic SH-SY5Y Cells via Stimulating Mitochondrial Dysfunction', International Journal of Molecular Sciences, vol. 21, no. 4, pp. 1370-1370.
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Increasing reports of neurological and psychiatric complications due to psychostimulant synthetic cathinones (SCs) have recently raised public concern. However, the precise mechanism of SC toxicity is unclear. This paucity of understanding highlights the need to investigate the in-vitro toxicity and mechanistic pathways of three SCs: butylone, pentylone, and 3,4-Methylenedioxypyrovalerone (MDPV). Human neuronal cells of SH-SY5Y were cultured in supplemented DMEM/F12 media and differentiated to a neuronal phenotype using retinoic acid (10 μM) and 12-O-tetradecanoylphorbol-13-acetate (81 nM). Trypan blue and lactate dehydrogenase assays were utilized to assess the neurotoxicity potential and potency of these three SCs. To investigate the underlying neurotoxicity mechanisms, measurements included markers of oxidative stress, mitochondrial bioenergetics, and intracellular calcium (Ca2+), and cell death pathways were evaluated at two doses (EC15 and EC40), for each drug tested. Following 24 h of treatment, all three SCs exhibited a dose-dependent neurotoxicity, characterized by a significant (p < 0.0001 vs. control) production of reactive oxygen species, decreased mitochondrial bioenergetics, and increased intracellular Ca2+ concentrations. The activation of caspases 3 and 7 implicated the orchestration of mitochondrial-mediated neurotoxicity mechanisms for these SCs. Identifying novel therapeutic agents to enhance an altered mitochondrial function may help in the treatment of acute-neurological complications arising from the illicit use of these SCs.

Li, M, Sun, B, Ao, Z, An, T & Wang, G 2020, 'Atomic-scale identification of influencing factors of sodium dendrite growth on different current collectors', Journal of Materials Chemistry A, vol. 8, no. 20, pp. 10199-10205.
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In the process of Na ion plating on SWCNTs and Cu/Al current collector surfaces, SWCNTs exhibit the highest electron transfer ability and the most stable electron configuration, inducing the instability of the Na dimer, but favour the presence of evenly distributed Na adatoms.

Li, M, Yang, Y, Iacopi, F, Nulman, J & Chappel-Ram, S 2020, '3D-Printed Low-Profile Single-Substrate Multi-Metal Layer Antennas and Array With Bandwidth Enhancement', IEEE Access, vol. 8, no. 99, pp. 217370-217379.
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This paper presents a few single-substrate multi-metal layer antennas using additively manufactured electronics (AME) solution based on piezoelectric additive fabrication. By vertically stacking metal layers in a 3D printed single substrate, the designed antenna prototype exhibits the advantages of wide bandwidth and ultra-low profile. For proof-of-concept, multi-layer linear polarization (LP) patch antenna elements and 2×2 LP antenna arrays are designed, fabricated, and measured. It verifies that the feeding network can be integrated into the same substrate of the antenna array element without increasing the size and profile of the array. Compared with the traditional single-layer LP patch antenna, the proposed LP patch antenna can improve the impedance bandwidth from 5.9% to 10.6% (three layers) and 83% (seven layers), respectively. All these designs can be fabricated in a single substrate with a thickness of 1.5 mm ( 0.031 λg ), which is an ideal solution for the applications where ultra-low profile and wideband patch antenna are expected. Finally, circular polarization (CP) patch antenna elements and 2×2 CP antenna arrays are fabricated and measured. Good agreements between the simulated and the measured results verify that wider impedance bandwidth and broader frequency range of under 3-dB axial ratio can be obtained by vertically stacking metal layers. The antennas are designed at sub-6GHz, which have great potentials for 5G consumer mobile electronics.

Li, Y, Zhu, J, Zhu, L, Li, Y & Lei, G 2020, 'A Dynamic Magnetostriction Model of Grain-Oriented Sheet Steels Based on Becker–Döring Crystal Magnetization Model and Jiles–Atherton Theory of Magnetic Hysteresis', IEEE Transactions on Magnetics, vol. 56, no. 3, pp. 1-5.
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Liu, Q, Tian, H, Dai, Z, Sun, H, Liu, J, Ao, Z, Wang, S, Han, C & Liu, S 2020, 'Nitrogen-doped Carbon Nanospheres-Modified Graphitic Carbon Nitride with Outstanding Photocatalytic Activity', Nano-Micro Letters, vol. 12, no. 1.
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AbstractMetals and metal oxides are widely used as photo/electro-catalysts for environmental remediation. However, there are many issues related to these metal-based catalysts for practical applications, such as high cost and detrimental environmental impact due to metal leaching. Carbon-based catalysts have the potential to overcome these limitations. In this study, monodisperse nitrogen-doped carbon nanospheres (NCs) were synthesized and loaded onto graphitic carbon nitride (g-C3N4, GCN) via a facile hydrothermal method for photocatalytic removal of sulfachloropyridazine (SCP). The prepared metal-free GCN-NC exhibited remarkably enhanced efficiency in SCP degradation. The nitrogen content in NC critically influences the physicochemical properties and performances of the resultant hybrids. The optimum nitrogen doping concentration was identified at 6.0 wt%. The SCP removal rates can be improved by a factor of 4.7 and 3.2, under UV and visible lights, by the GCN-NC composite due to the enhanced charge mobility and visible light harvesting. The mechanism of the improved photocatalytic performance and band structure alternation were further investigated by density functional theory (DFT) calculations. The DFT results confirm the high capability of the GCN-NC hybrids to activate the electron–hole pairs by reducing the band gap energy and efficiently separating electron/hole pairs. Superoxide and hydroxyl radicals are subsequently produced, leading to the efficient SCP removal.

Liu, X, Zhao, Y, Zhu, J, Chen, Z & Huang, S 2020, 'Multi-Objective Robust Optimization of a Dual-Flux-Modulator Magnetic Geared Machine With Hybrid Uncertainties', IEEE Transactions on Energy Conversion, vol. 35, no. 4, pp. 2106-2115.
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Liu, Y, Li, H-W & Huang, Z 2020, 'Editorial: Metal Hydride-Based Energy Storage and Conversion Materials', Frontiers in Chemistry, vol. 8, p. 675.
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Lu, L, Cao, X, Shen, Z, Li, L, Huo, J, Chen, W, Liu, C & Liu, H 2020, 'Electrospun nitrogen-doped carbon nanofibers for electrocatalysis', Sustainable Materials and Technologies, vol. 26, pp. e00221-e00221.
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© 2020 Electrospinning technology has attracted wide attention in the field of electrocatalysis due to its easy operation, environmental friendliness and large-scale production capacity. Electrospun nitrogen-doped carbon fibers have the advantages of uniform size, controllable defects, orderly arrangement, and mass production, which benefits their practical applications in electrocatalysis. Nitrogen doping can activate the adjacent carbon atoms. The graphitic nitrogen can donate electron to the π-conjugated carbon system and the pyridinic nitrogen has electron-attracting effect on the adjacent carbon atom, thereby achieving improved electrocatalytic performance. However, the catalytic activity of pure nitrogen-doped carbon fibers is insufficient for practical applications. Therefore, researchers have conducted extensive investigations on optimizing the structure and composition of carbon fibers. In this review, electrospun N-doped carbon nanofibers with various architectures are summarized, and the advantages of heteroatom doping and fiber structure are grasped. The application progresses of nitrogen doped carbon nanofibers in the fields of oxygen and carbon dioxide reduction reaction, hydrogen and oxygen evolution reaction are reviewed. Finally, the future development of electrospun carbon nanofiber catalysts is prospected.

Luo, C, Rahman, MA, Phillips, MR, Ton-That, C, Butterling, M, Wagner, A & Ling, FC-C 2020, 'Electrical and optical properties in O-polar and Zn-polar ZnO films grown by pulsed laser deposition', Thin Solid Films, vol. 711, pp. 138303-138303.
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© 2020 Elsevier B.V. O-polar and Zn-polar ZnO films were grown on c-sapphire by pulsed laser deposition. Positron annihilation spectroscopy study reveals that the VZn-related defects in the ZnO films with different polarities are different in structure and their thermal evolution is different. Hall effect measurement and luminescence spectroscopy reveal that the electrical and optical properties and their corresponding thermal evolution are strongly dependent on the polarity of the film. The luminescence spectra of the as-grown Zn-polar ZnO film is signified by a negligible green defect emission (at ~ 2.4 eV) and strong near band edge emission as compared with the O-polar film. The as-grown Zn-polar film exhibited a lower electron concentration (2 × 1018 cm−3) than that of the O-polar film (6 × 1018 cm−3); this difference is attributed to their different H concentrations. For the O-polar film, the electron concentration decreased with annealing temperature Tanneal, reaching a minimum at 700°C and then increased to 4 × 1018 cm−3 at Tanneal = 900 °C. In comparison, the electron concentration of the Zn-polar ZnO film monotonically decreased with Tanneal attaining a value of ~1 × 1017 cm−3 at Tanneal = 900 °C, 40 times smaller than that of the O-polar film. The cause for the differences in the optical and electrical properties for the O-polar and Zn-polar films is explained by the presence of different defects in these films.

Luo, X, Lu, X, Chen, X, Chen, Y, Song, C, Yu, C, Wang, N, Su, D, Wang, C, Gao, X, Wang, G & Cui, L 2020, 'A robust flame retardant fluorinated polyimide nanofiber separator for high-temperature lithium–sulfur batteries', Journal of Materials Chemistry A, vol. 8, no. 29, pp. 14788-14798.
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A multifunctional fluorinated polyimide nanofiber separator for high-performance lithium–sulfur batteries.

Luo, X, Lu, X, Chen, X, Chen, Y, Yu, C, Su, D, Wang, G & Cui, L 2020, 'A functional hyperbranched binder enabling ultra-stable sulfur cathode for high-performance lithium-sulfur battery', Journal of Energy Chemistry, vol. 50, pp. 63-72.
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© 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Binders are of vital importance in stabilizing the cathodes to enhance the cycling stability of lithium-sulfur (Li-S) batteries. However, conventional binders are typically confronted with the drawback of inability for adsorbing lithium polysulfide (LiPS), thus resulting in severe active material losing and rapid capacity fading. Herein, a novel water-soluble hyperbranched poly(amidoamine) (HPAA) binder with controllable hyperbranched molecular structure and abundant amino end groups for Li-S battery is designed and fabricated, which can improve efficient adsorption for LiPS and stability of the sulfur cathodes. Besides, the strong intermolecular hydrogen bonds in HPAA binder can contribute to the structural stability of S cathode and integration of the conductive paths. Therefore, the Li-S battery with this functional binder exhibits excellent cycle performance with a capacity retention of 91% after 200 cycles at 0.1 C. Even at a high sulfur loading of 5.3 mg cm−2, a specific capacity of 601 mA h g−1 can also be achieved. Density functional theory (DFT) calculation further demonstrates that the enhanced electrochemical stability derives from the high binding energy between amino groups and LiPS and the wide electrochemical window (6.87 eV) of HPAA molecule. Based on the above all, this functional polymer will lighten a new species of binders for eco-friendly sulfur cathodes and significantly promote the practical applications of high-performance Li-S batteries.

Luo, X, Lu, X, Chen, Y, Chen, X, Guo, H, Song, C, Wang, N, Su, D, Wang, G, Cui, L & Liu, Y 2020, 'A multifunctional polyimide nanofiber separator with a self-closing polyamide–polyvinyl alcohol top layer with a Turing structure for high-performance lithium–sulfur batteries', Materials Advances, vol. 1, no. 9, pp. 3449-3459.
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The development of commercial lithium–sulfur (Li–S) batteries is typically restricted by the intrinsic drawbacks of the dissolutiion and shuttling of lithium polysulfides (LPS) and the uncontrollable growth of lithium dendrites.

Ma, B, Zheng, J, Lei, G, Zhu, J, Jin, P & Guo, Y 2020, 'Topology Optimization of Ferromagnetic Components in Electrical Machines', IEEE Transactions on Energy Conversion, vol. 35, no. 2, pp. 786-798.
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IEEE This paper presents the topology optimization of ferromagnetic components in electrical machines by using the density method. Explicit expressions of machine performance based on the principle of electromechanical energy conversion are derived and incorporated in the finite element model. Because the gradient-based algorithm is employed for efficient optimization, the performance sensitivities with respect to the design variables are derived subsequently. An optimization framework is then proposed to optimize effectively the electrical machine performance, such as the flux linkage, back electromotive force, torque profile including torque density and torque ripples. Two design examples are reported to confirm the feasibility and effectiveness of the presented topology optimization approach. The accuracy of optimal solutions is verified by using the commercial electromagnetic analysis software ANSYS MAXWELL.

Ma, B, Zheng, J, Zhu, J, Wu, J, Lei, G & Guo, Y 2020, 'Robust Design Optimization of Electrical Machines Considering Hybrid Random and Interval Uncertainties', IEEE Transactions on Energy Conversion, vol. 35, no. 4, pp. 1815-1824.
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© 1986-2012 IEEE. For robust design optimization (RDO) of electrical machines, cases with random uncertainty and interval uncertainty are generally investigated separately. Accordingly, the performance fluctuation analysis under uncertainty is based on random method and interval method respectively. However, the problem with hybrid uncertainties can also be met yet rarely researched. Under this circumstance, the uncertainty analysis methods for a single type of uncertainty may no longer be applicable, which challenges the robust optimization conduction. For effective RDO of electrical machines with hybrid uncertainties, this article presents a robust optimizer based on evolutionary algorithms and the polynomial chaos Chebyshev interval (PCCI) method. The PCCI method is utilized for effectively modeling the fluctuations caused by the hybrid uncertainty with a small number of samples. As additional enhancements, the filtering strategy for the algorithm with deterministic constraints is proposed to reduce the solutions that require robustness analysis in each iteration and accelerate the optimization further while not affecting the global convergence ability. A design example of a brushless DC motor considering hybrid uncertainties is analyzed and optimized. The results confirm the feasibility of the proposed method.

Malekjamshidi, Z, Jafari, M, Zhu, J & Rivera, M 2020, 'Design, Implementation, and Stability Analysis of a Space Vector Modulated Direct Matrix Converter for Power Flow Control in a More Reliable and Sustainable Microgrid', Sustainability, vol. 12, no. 20, pp. 8591-8591.
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This paper presents a detailed study on technical points of design, control, stability analysis, and hardware development of a direct matrix converter with power flow control for microgrid applications. The converter is used as an interface between a microgrid AC bus and a variable-frequency load, e.g., an induction machine. The main steps of the converter design include the design of input filter, stabilization, commutation, and protection techniques. Practical guidelines are provided for the direct conversion and transmission of modulation and control procedures to the logic processing devices. Through a detailed study of stabilization technique using damping resistors, the stability region of the converter is determined by using the linearized state-space equations. A prototype direct matrix converter has been developed by the proposed design procedures, and experimentally tested for a variable frequency load.

Manyam, J, Ton-That, C & Phillips, MR 2020, 'Cathodoluminescence study of electric field induced migration of defects in single crystal m-plane ZnO', Journal of Applied Physics, vol. 127, no. 8, pp. 085705-085705.
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Internal electric fields can have a significant effect on the behavior of charged defects, dopants, and impurities in operating electronic devices that can adversely impact on their long-term performance and reliability. In this paper, we investigate the redistribution of charged centers in single crystal m-plane ZnO under the action of a DC electric field at 873 K using in-plane and in-depth spatially resolved cathodoluminescence (CL) spectroscopy. The CL intensities of the ultra-violet near band edge (NBE) emission at 3.28 eV and green luminescence (GL) at 2.39 eV were observed to both uniformly increase on the anode side of the electrode gap. Conversely, toward the cathode, the NBE and GL steadily decrease and increase, respectively. The GL quenched after hydrogen donor doping, confirming that the emission is related to acceptor-like centers. Based on the electro-migration and hydrogen doping results, the GL is attributed to radiative recombination involving ZniandVZn pairs. The intensity of an orange luminescence centered at 2.01 eV was unaffected by the electric field and is assigned to substitutional Li acceptors.

Meng, L, Ren, Y, Zhou, Z, Li, C, Wang, C & Fu, S 2020, 'Monodisperse silica nanoparticle suspension for developing latent blood fingermarks', Forensic Sciences Research, vol. 5, no. 1, pp. 38-46.
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Moezzi, A, Lee, P-S, McDonagh, AM & Cortie, MB 2020, 'On the thermal decomposition of zinc hydroxide nitrate, Zn5(OH)8(NO3)2⋅2H2O', Journal of Solid State Chemistry, vol. 286, pp. 121311-121311.
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© 2020 Elsevier Inc. The layered basic hydroxide Zn5(OH)8(NO3)2⋅2H2O can be thermally decomposed to ZnO via a series of intermediary compounds. Application of in situ X-ray diffraction to dry powder samples reveals three reactions: formation of anhydrous Zn5(OH)8(NO3)2, then de-hydroxylation to Zn3(OH)4(NO3)2 and, finally, decomposition of the latter to ZnO. In contrast, thermal analysis and mass spectroscopy of the evolved volatiles suggests that four reactions take place. Whereas de-hydroxylation reactions only produce H2O, there is also a distinctive pulse of NOx and O2 at the end of the sequence of reactions. The evidence points to the formation of an intermediate, poorly crystalline phase with a stoichiometry of [Zn(OH)2-x]⋅[NO3]x (1 ​< ​x ​< ​2) during the final stages of the reaction sequence. Isothermal calcination of Zn5(OH)8(NO3)2⋅2H2O at 120 ​°C showed that the anhydrous Zn5(OH)8(NO3)2 compound is unstable, rehydrating very rapidly on cooling or decomposing within 6 or 7 ​h at 120 ​°C to Zn3(OH)4(NO3)2 (at a rate of 1.33 ​× ​10-4 s-1). Zn3(OH)4(NO3)2 itself decomposes slowly to ZnO at 120 ​°C, but the process is slower (5.33 ​× ​10-6 s-1) and there was still considerable Zn3(OH)4(NO3)2 present even after 140 ​h. The mixtures of Zn3(OH)4(NO3)2 and ZnO prepared by calcination are unstable under ambient conditions and react with moisture to reform Zn5(OH)8(NO3)2⋅2H2O.

Nazrul Islam, SMK, Cortie, MB & Wang, X 2020, 'Grape juice: an effective liquid additive for significant enhancement of thermoelectric performance of Cu₂Se', Journal of Materials Chemistry A, vol. 8, no. 33, pp. 16913-16919.
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Grape juice provides a fine-scale and well-mixed dispersion of elemental carbon in a Cu₂Se matrix for ultra-high thermoelectric performance.

Pissuwan, D, Gazzana, C, Mongkolsuk, S & Cortie, MB 2020, 'Single and multiple detections of foodborne pathogens by gold nanoparticle assays', WIREs Nanomedicine and Nanobiotechnology, vol. 12, no. 1, pp. e1584-e1584.
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AbstractA late detection of pathogenic microorganisms in food and drinking water has a high potential to cause adverse health impacts in those who have ingested the pathogens. For this reason there is intense interest in developing precise, rapid and sensitive assays that can detect multiple foodborne pathogens. Such assays would be valuable components in the campaign to minimize foodborne illness. Here, we discuss the emerging types of assays based on gold nanoparticles (GNPs) for rapidly diagnosing single or multiple foodborne pathogen infections. Colorimetric and lateral flow assays based on GNPs may be read by the human eye. Refractometric sensors based on a shift in the position of a plasmon resonance absorption peak can be read by the new generation of inexpensive optical spectrometers. Surface‐enhanced Raman spectroscopy and the quartz microbalance require slightly more sophisticated equipment but can be very sensitive. A wide range of electrochemical techniques are also under development. Given the range of options provided by GNPs, we confidently expect that some, or all, of these technologies will eventually enter routine use for detecting pathogens in food.This article is categorized under:Diagnostic Tools > Biosensing

Poon, C, Chou, J, Cortie, M & Kabakova, I 2020, 'Brillouin imaging for studies of micromechanics in biology and biomedicine: from current state-of-the-art to future clinical translation', Journal of Physics: Photonics, vol. 3, no. 1, pp. 1-25.
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Brillouin imaging is increasingly recognized to be a powerful technique thatenables non-invasive measurement of the mechanical properties of cells andtissues on a microscopic scale. This provides an unprecedented tool forinvestigating cell mechanobiology, cell-matrix interactions, tissuebiomechanics in healthy and disease conditions and other fundamental biologicalquestions. Recent advances in optical hardware have particularly acceleratedthe development of the technique, with increasingly finer spectral resolutionand more powerful system capabilities. We envision that further developmentswill enable translation of Brillouin imaging to assess clinical specimens andsamples for disease screening and monitoring. The purpose of this review is tosummarize the state-of-the-art in Brillouin microscopy and imaging with aspecific focus on biological tissue and cell measurements. Key system andoperational requirements will be discussed to facilitate wider application ofBrillouin imaging along with current challenges for translation of thetechnology for clinical and medical applications.

Pradeepkumar, A, Amjadipour, M, Mishra, N, Liu, C, Fuhrer, MS, Bendavid, A, Isa, F, Zielinski, M, Sirikumara, HI, Jayasekara, T, Gaskill, DK & Iacopi, F 2020, 'p-Type Epitaxial Graphene on Cubic Silicon Carbide on Silicon for Integrated Silicon Technologies', ACS Applied Nano Materials, vol. 3, no. 1, pp. 830-841.
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Copyright © 2019 American Chemical Society. The synthesis of graphene on cubic silicon carbide on silicon pseudosubstrates draws enormous interest due to the potential integration of the 2D material with the well-established silicon technology and processing. However, the control of transport properties over large scales on this platform, essential for integrated electronics and photonics applications, has lagged behind so far, due to limitations such as 3C-SiC/Si interface instability and nonuniform graphene coverage. We address these issues by obtaining an epitaxial graphene (EG) onto 3C-SiC on a highly resistive silicon substrate using an alloy-mediated, solid-source graphene synthesis. We report the transport properties of EG grown over large areas directly on 3C-SiC(100) and 3C-SiC(111) substrates, and we present the corresponding physical models. We observe that the carrier transport of EG/3C-SiC is dominated by the graphene-substrate interaction rather than the EG grain size, sharing the same conductivity and same inverse power law as EG on 4H- or 6H-SiC(0001) substrates - although the grain sizes for the latter are vastly different. In addition, we show that the induced oxidation/silicates at the EG/3C-SiC interface generate a p-type charge in this graphene, particularly high for the EG/3C-SiC(001). When silicates are at the interface, the presence of a buffer layer in the EG/3C-SiC(111) system is found to reduce somewhat the charge transfer. This work also indicates that a renewed focus on the understanding and engineering of the EG interfaces could very well enable the long sought-after graphene-based electronics and photonics integrated on silicon.

Pradeepkumar, A, Gaskill, DK & Iacopi, F 2020, 'Electronic and Transport Properties of Epitaxial Graphene on SiC and 3C-SiC/Si: A Review', Applied Sciences, vol. 10, no. 12, pp. 4350-4350.
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The electronic and transport properties of epitaxial graphene are dominated by the interactions the material makes with its surroundings. Based on the transport properties of epitaxial graphene on SiC and 3C-SiC/Si substrates reported in the literature, we emphasize that the graphene interfaces formed between the active material and its environment are of paramount importance, and how interface modifications enable the fine-tuning of the transport properties of graphene. This review provides a renewed attention on the understanding and engineering of epitaxial graphene interfaces for integrated electronics and photonics applications.

Qian, Z, Li, X, Sun, B, Du, L, Wang, Y, Zuo, P, Yin, G, Zhang, J, Sun, B & Wang, G 2020, 'Unraveling the Promotion Effects of a Soluble Cobaltocene Catalyst with Respect to Li–O₂ Battery Discharge', The Journal of Physical Chemistry Letters, vol. 11, no. 17, pp. 7028-7034.
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The discharge process of a nonaqueous Li-O2 battery at the cathode is the direct oxygen reduction reaction (ORR) with the formation of discharge product, e.g., Li2O2, deposits on the cathode surface. The aggressive superoxide intermediate generated during the ORR severely degrades the organic electrolyte and carbon-based cathodes. To avoid the formation of superoxide species and promote the growth of Li2O2 in the electrolyte solution, we employ a soluble cobaltocene [Co(C5H5)2, Cp2Co] as a homogeneous molecule catalyst to boost the discharge performance of Li-O2 batteries. Owing to the unique chemical reactivity of Cp2Co with molecular oxygen, the electrochemistry of the discharge process at the cathode is the (Cp2Co)2II-O22- adduct-mediated process rather than direct electrochemical oxygen reduction, thereby avoiding the formation of aggressive superoxide intermediate. In addition, the strong intermolecular attraction between Cp2Co and the newly formed Li2O2 promotes the solution phase growth of Li2O2, which effectively suppresses electrode passivation.

Riaz, MA, Yuan, Z, Mahmood, A, Liu, F, Sui, X, Chen, J, Huang, Q, Liao, X, Wei, L & Chen, Y 2020, 'Hierarchically porous carbon nanofibers embedded with cobalt nanoparticles for efficient H2O2 detection on multiple sensor platforms', Sensors and Actuators B: Chemical, vol. 319, pp. 128243-128243.
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Romero, E, Valenzuela, VM, Kermany, AR, Sementilli, L, Iacopi, F & Bowen, WP 2020, 'Engineering the Dissipation of Crystalline Micromechanical Resonators', Physical Review Applied, vol. 13, no. 4.
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© 2020 American Physical Society. © 2020 American Physical Society. High-quality micro- and nanomechanical resonators are widely used in sensing, communications, and timing, and have future applications in quantum technologies and fundamental studies of quantum physics. Crystalline thin films are particularly attractive for such resonators due to their prospects for high quality, high intrinsic stress, high yield strength, and low dissipation. However, when such films are grown on a silicon substrate, interfacial defects arising from lattice mismatch with the substrate have been postulated to introduce additional dissipation. Here, we develop a back-side etching process for single-crystal silicon carbide microresonators that allows us to quantitatively verify this prediction. By engineering the geometry of the resonators and removing the defective interfacial layer, we achieve quality factors exceeding a million in silicon carbide trampoline resonators at room temperature, a factor of five higher than those achieved without removal of the interfacial defect layer. We predict that similar devices fabricated from ultrahigh-purity silicon carbide, leveraging its high yield strength, could enable room-temperature quality factors as high as 6×109.

Rufangura, P, Folland, TG, Agrawal, A, Caldwell, JD & Iacopi, F 2020, 'Towards low- loss on-chip nanophotonics with coupled graphene and silicon carbide: a review', Journal of Physics: Materials, vol. 3, no. 3, pp. 032005-032005.
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Abstract The ability to control the interaction of light and matter at the nanoscale is at the heart of the field of nanophotonics. This subdiffractional confinement of light can be achieved through the stimulation of surface polaritons, most notably surface plasmon polaritons (SPPs). However, the high optical losses and lack of tunability of conventional plasmonic materials have hindered major progress in this field. In the search for alternative low-loss and tunable materials, graphene and polar dielectric materials are viewed as potential alternatives to more common metal-based plasmonic materials. In particular, the possibility of combining the tunable nature of graphene SPPs with the high-quality factors and long lifetimes of surface phonon-polaritons (SPhPs) modes supported in polar dielectric materials (e.g. SiC) offers great promise for advanced nanophotonic applications. The combination of graphene SPPs and SPhPs supported in SiC is even more pertinent as this material system can be realized in the form of epitaxial graphene (EG), whereby sublimation of silicon from a SiC results in a surface reconstruction into a graphene surface termination. This offers an ideal technology platform for realizing hybrid SPP-SPhP modes. In this review, we outline advances in graphene plasmonics and the generation of SPhPs in polar materials, in the context of epitaxial graphene. We review recent attempts at realizing such coupling of graphene SPPs with phonon and SPhP modes in SiC, as well as covering such modes in other polar materials and conclude with an overview of advantages and challenges for further advancement of nanophotonics based on graphene on silicon carbide for on-chip light manipulation.

Sarker, PC, Guo, Y, Lu, HY & Zhu, JG 2020, 'A generalized inverse Preisach dynamic hysteresis model of Fe-based amorphous magnetic materials', Journal of Magnetism and Magnetic Materials, vol. 514, pp. 167290-167290.
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Fe-based amorphous magnetic materials are attracting more and more attentions in the application of low and medium frequency transformers due to their favorable properties of low core loss and high saturation magnetic flux density. Accurate modelling of their static and dynamic characteristics is required for analysis and design optimization of low and medium frequency transformers. In particular, for numerical analysis using the vectorial magnetic potential, an inverse magnetic hysteresis model is needed to predict the magnetic field strength from the magnetic flux density. When the excitation varies with time, the magnetic hysteresis model must be able to predict the dynamic hysteresis characteristics. This paper presents a generalized inverse Preisach dynamic hysteresis model for dynamic characterization of Fe-based magnetic materials. This model incorporates the reversible magnetization and magnetization dependent hysteresis, as well as all core loss components, including the hysteresis, eddy current, and excess losses. The proposed model can predict accurately the magnetic field strength from the magnetic flux density and hence accurate core losses. The predicted results are verified by experimental measurements.

Shan, Y, Hu, J, Liu, M, Zhu, J & Guerrero, JM 2020, 'Model Predictive Voltage and Power Control of Islanded PV-Battery Microgrids With Washout-Filter-Based Power Sharing Strategy', IEEE Transactions on Power Electronics, vol. 35, no. 2, pp. 1227-1238.
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© 1986-2012 IEEE. This paper proposes a new control strategy of microgrids for the improved voltage quality. In the existing control techniques, the droop control is commonly adopted as a decentralized power sharing method at the cost of voltage deviations. Besides, the conventional cascaded control featuring relatively slow dynamic response shows difficulties in handling the fluctuation of renewable energy outputs, leading to further voltage quality deterioration. In this paper, an advanced model predictive power control strategy by considering the battery constraints is proposed for the bidirectional dc-dc converters to smooth the solar photovoltaic (PV) outputs and stabilize the dc-bus voltages. A model predictive voltage control scheme taking into account the voltage changing trend is then developed to control the distributed inverters to improve the output ac voltages. Furthermore, a washout-filter-based power sharing approach with the plug-and-play capability is adopted to achieve a proper load sharing among parallel inverters and mitigate the voltage deviation. The proposed control strategy is numerically simulated in MATLAB/Simulink and experimentally verified by hardware-in-the-loop tests under the condition of fluctuating PV outputs and variable power demands. (This paper is accompanied by a video showing the hardware-in-the-loop test.)

Shi, Z, Sun, X, Lei, G, Yang, Z, Guo, Y & Zhu, J 2020, 'Analysis and Optimization of Radial Force of Permanent-Magnet Synchronous Hub Motors', IEEE Transactions on Magnetics, vol. 56, no. 2, pp. 1-4.
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© 1965-2012 IEEE. Permanent-magnet synchronous hub motors (PMSHMs) have been investigated for electric vehicles. However, there are some challenges such as effective cooling and radial force. As PMSHMs are installed on the wheels, the radial force will directly affect the ride comfort of the vehicle. This article presents the analysis and optimization of the radial force for PMSHMs. The radial force densities of the symmetry and asymmetry PMSHMs are analyzed first. It is found that the symmetry PMSHMs have balanced force, while the asymmetry PMSHMs normally have big unbalanced radial force and vibration. To reduce the radial force of the asymmetry PMSHMs, an improved sequential Taguchi optimization method (ISTOM) with mixed orthogonal array is presented for an asymmetry PMSHM in this article. It can be found that the proposed method is efficient and can significantly reduce the radial force of the hub motor.

Sornalingam, K, McDonagh, A, Canning, J, Cook, K, Johir, MAH, Zhou, JL & Ahmed, MB 2020, 'Photocatalysis of 17α-ethynylestradiol and estriol in water using engineered immersible optical fibres and light emitting diodes', Journal of Water Process Engineering, vol. 33, pp. 101075-101075.
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© 2019 Elsevier Ltd This research aims to promote photocatalysis of endocrine disrupting chemicals (EDCs) in water. Two reactor setups with (i) modified air-clad optical fibres and (ii) waterproof LED strips were utilised to transmit light to photocatalysts P25 TiO2 and gold-modified TiO2 (Au-TiO2). The performances to photodegrade 17α-ethynylestradiol (EE2) and estriol (E3) under Cool White and UVA high efficacy LEDs were examined. Au-TiO2 showed superior photocatalytic activity for EE2 removal over P25 TiO2. The pseudo first-order rate constants for EE2 photocatalysis under UVA were 0.55 h−1 and 0.89 h−1 for TiO2 and Au-TiO2, respectively. E3 was effectively degraded by Au-TiO2 in the immersible LED strip reactor (0.13 h−1).

Su, DW, Ran, J, Zhuang, ZW, Chen, C, Qiao, SZ, Li, YD & Wang, GX 2020, 'Atomically dispersed Ni in cadmium-zinc sulfide quantum dots for high-performance visible-light photocatalytic hydrogen production', Science Advances, vol. 6, no. 33.
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Visible-light photocatalytic hydrogen is optimized using the synergistic effect of single atoms with their coordinating element.

Sun, B, Xiong, P, Maitra, U, Langsdorf, D, Yan, K, Wang, C, Janek, J, Schröder, D & Wang, G 2020, 'Design Strategies to Enable the Efficient Use of Sodium Metal Anodes in High‐Energy Batteries', Advanced Materials, vol. 32, no. 18, pp. e1903891-1903891.
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AbstractSodium‐based batteries have attracted considerable attention and are recognized as ideal candidates for large‐scale and low‐cost energy storage. Sodium (Na) metal anodes are considered as one of the most promising anodes for next‐generation, high‐energy, Na‐based batteries owing to their high theoretical specific capacity (1166 mA h g−1) and low standard electrode potential. Herein, an overview of the recent developments in Na metal anodes for high‐energy batteries is provided. The high reactivity and large volume expansion of Na metal anodes during charge and discharge make the electrode/electrolyte interphase unstable, leading to the formation of Na dendrites, short cycle life, and safety issues. Design strategies to enable the efficient use of Na metal anodes are elucidated, including liquid electrolyte engineering, electrode/electrolyte interface optimization, sophisticated electrode construction, and solid electrolyte engineering. Finally, the remaining challenges and future research directions are identified. It is hoped that this progress report will shape a consistent view of this field and provide inspiration for future research to improve Na metal anodes and enable the development of high‐energy sodium batteries.

Sun, X, Cao, J, Lei, G, Guo, Y & Zhu, J 2020, 'Speed Sensorless Control for Permanent Magnet Synchronous Motors Based on Finite Position Set', IEEE Transactions on Industrial Electronics, vol. 67, no. 7, pp. 6089-6100.
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© 1982-2012 IEEE. This article presents a novel method for the sensorless control of interior permanent-magnet synchronous motors. An iterative search strategy based on dichotomy is proposed to provide a finite number of rotor position angles with good accuracy. These position angles are used to calculate the back electromotive force (EMF) in d-axis. The optimal rotor position angle is the one that yields a back EMF minimizing the defined cost function. With the increase of the iterations, the accuracy of rotor position angle increases geometrically. To effectively extract the back EMF signal under the low-speed condition, the high-frequency signal injection method is used to realize the low-speed operation of the motor. A hybrid control strategy is adopted to achieve the smooth switching from the low-speed to high-speed. The performance of the proposed method has been validated experimentally and compared with that of the conventional phase locked loop under different conditions.

Sun, X, Diao, K, Lei, G, Guo, Y & Zhu, J 2020, 'Real-Time HIL Emulation for a Segmented-Rotor Switched Reluctance Motor Using a New Magnetic Equivalent Circuit', IEEE Transactions on Power Electronics, vol. 35, no. 4, pp. 3841-3849.
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Sun, X, Hu, C, Lei, G, Guo, Y & Zhu, J 2020, 'State Feedback Control for a PM Hub Motor Based on Gray Wolf Optimization Algorithm', IEEE Transactions on Power Electronics, vol. 35, no. 1, pp. 1136-1146.
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© 1986-2012 IEEE. This paper presents an optimal control strategy for a permanent-magnet synchronous hub motor (PMSHM) drive using the state feedback control method plus the gray wolf optimization (GWO) algorithm. First, the linearized PMSHM mathematical model is obtained by voltage feedforward compensation. Second, to acquire satisfactory dynamics of speed response and zero d-axis current, the discretized state-space model of the PMSHM is augmented with the integral of rotor speed error and integral of d-axis current error. Then, the GWO algorithm is employed to acquire the weighting matrices Q and R in linear quadratic regulator optimization process. Moreover, a penalty term is introduced to the fitness index to suppress overshoots effectively. Finally, comparisons among the GWO-based state feedback controller (SFC) with and without the penalty term, the conventional SFC, and the genetic algorithm enhanced proportional-integral controllers are conducted in both simulations and experiments. The comparison results show the superiority of the proposed SFC with the penalty term in fast response.

Sun, X, Hu, C, Lei, G, Yang, Z, Guo, Y & Zhu, J 2020, 'Speed Sensorless Control of SPMSM Drives for EVs With a Binary Search Algorithm-Based Phase-Locked Loop', IEEE Transactions on Vehicular Technology, vol. 69, no. 5, pp. 4968-4978.
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© 1967-2012 IEEE. This article presents a new method to extract accurate rotor position for the speed sensorless control of surface-mounted permanent-magnet synchronous motors (SPMSMs), based on the back electromotive force (EMF) information. The concept of finite control set-model predictive control is employed, and its cost function is related to the back EMF. An optimal voltage vector is selected from several given voltage vectors by comparing their fitness values. Moreover, the position space is divided into four sectors, and the fitness of each sector boundary is calculated and compared. The rotor position is first located in the sector surrounded by two boundaries that minimize the cost function. Then the selected sector is split into two parts, and the binary search algorithm is applied to reduce the sector area to improve the accuracy of position estimation. To overcome the drawback of the back EMF-based sensorless scheme, an I-f startup method is employed to accelerate the motor to the desired speed. An experiment has been carried out to compare the performance of the proposed method and the conventional phase-locked loop (PLL) in terms of steady-state and transient conditions.

Sun, X, Shi, Z, Cai, Y, Lei, G, Guo, Y & Zhu, J 2020, 'Driving-Cycle-Oriented Design Optimization of a Permanent Magnet Hub Motor Drive System for a Four-Wheel-Drive Electric Vehicle', IEEE Transactions on Transportation Electrification, vol. 6, no. 3, pp. 1115-1125.
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© 2015 IEEE. The electrical drive system is crucial to the drive performance and safety of electric vehicles (EVs). In contrast to the traditional two-wheel-driven EVs, the hub motor four-wheel-drive system can steer the vehicle by controlling the torque and speed of each wheel independently, yielding a very simple distributed drivetrain with high efficiency and reliability. This article presents a system-level design optimization method for a permanent magnet hub motor drive system for a campus patrol EV based on a practical driving cycle. An outer rotor permanent-magnet synchronous hub motor (PMSHM) and an improved model predicate current control are proposed for the drive system. Due to the lack of reducers, the direct-drive PMSHM needs to face more complex working conditions and design constraints. In the implementation, the motor design requirements are obtained through the collection of practical EV driving cycles on the campus. Based on these requirements, two models are proposed as the preliminary designs for the PMSHM. To improve their performance, an efficient multiobjective optimization method is employed to the motor considering different operational conditions. The finite-element model and thermal network model are employed to verify the performance of the optimized PMSHM. An optimal design scheme is selected by comparing the comprehensive performance of the two optimized motors. In addition, a duty-cycle model predictive current control is adopted to drive the motor. Finally, a prototype is developed and tested, and the experimental results are presented.

Sun, X, Wang, C, Su, D, Wang, G & Zhong, Y 2020, 'Application of Photocatalytic Materials in Sensors', Advanced Materials Technologies, vol. 5, no. 5, pp. 1900993-1900993.
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AbstractPhotocatalysis technology can not only decompose water, toxic and harmful substances in the environment, but also directly convert solar energy into electricity and other clean energy. Therefore, the application of photocatalytic materials in sensors has great potential. The purpose of this paper is to review and discuss the application and potential of photocatalytic materials in sensors. The content includes the application of various photocatalytic materials in sensors. The photocatalytic materials mainly include n‐type semiconductor materials TiO2, ZnO, SnO2, Fe2O3, WO3, In2O3 and nonmetallic semiconductor C3N4. Sensors include gas sensors, photoelectrochemical sensors, electrochemical sensors, photocatalytic sensors, and other sensors. The results show that photocatalytic materials are most widely used in gas sensors. In addition to using photocatalytic materials to detect gas, the most common method is to use photocatalytic materials to detect the concentration of metal ions and organic substances in water. The most widely used photocatalytic material is titanium dioxide, and C3N4 as a nonmetallic semiconductor is rarely used in sensors. It can be concluded that photocatalytic materials have great potential in the application of sensors, among which C3N4 as a nonmetallic semiconductor photocatalytic material has more potential.

Tang, K, Xiao, J, Li, X, Wang, D, Long, M, Chen, J, Gao, H, Chen, W, Liu, C & Liu, H 2020, 'Advances of Carbon-Based Materials for Lithium Metal Anodes', Frontiers in Chemistry, vol. 8.
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Tang, X, Zhou, D, Li, P, Guo, X, Sun, B, Liu, H, Yan, K, Gogotsi, Y & Wang, G 2020, 'MXene‐Based Dendrite‐Free Potassium Metal Batteries', Advanced Materials, vol. 32, no. 4, pp. 1906739-1906739.
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AbstractPotassium metal batteries are considered as attractive alternatives beyond lithium‐ion batteries. However, uncontrollable dendrite growth on the potassium metal anode has restrained their practical applications. A high‐performance potassium anode achieved by confining potassium metal into a titanium‐deficient nitrogen‐containing MXene/carbon nanotube freestanding scaffold is reported. The high electronic transport and fast potassium diffusion in this scaffold enable reduced local current density and homogeneous ionic flux during plating/stripping processes. Furthermore, as verified by theoretical calculations and experimental investigations, such “potassium‐philic” MXene sheets can induce the nucleation of potassium, and guide potassium to uniformly distribute in the scaffold upon cycling. Consequently, the as‐developed potassium metal anodes exhibit a dendrite‐free morphology with high Coulombic efficiency and long cycle life during plating/stripping processes. Such anodes also deliver significantly improved electrochemical performances in potassium–sulfur batteries compared with bare potassium metal anodes. This work can provide a new avenue for developing potassium metal‐based batteries.

Tian, H, Tian, H, Wang, S, Chen, S, Zhang, F, Song, L, Liu, H, Liu, J & Wang, G 2020, 'Author Correction: High-power lithium–selenium batteries enabled by atomic cobalt electrocatalyst in hollow carbon cathode', Nature Communications, vol. 11, no. 1.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Tian, H, Tian, H, Wang, S, Chen, S, Zhang, F, Song, L, Liu, H, Liu, J & Wang, G 2020, 'High-power lithium–selenium batteries enabled by atomic cobalt electrocatalyst in hollow carbon cathode', Nature Communications, vol. 11, no. 1.
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AbstractSelenium cathodes have attracted considerable attention due to high electronic conductivity and volumetric capacity comparable to sulphur cathodes. However, practical development of lithium-selenium batteries has been hindered by the low selenium reaction activity with lithium, high volume changes and rapid capacity fading caused by the shuttle effect of polyselenides. Recently, single atom catalysts have attracted extensive interests in electrochemical energy conversion and storage because of unique electronic and structural properties, maximum atom-utilization efficiency, and outstanding catalytic performances. In this work, we developed a facile route to synthesize cobalt single atoms/nitrogen-doped hollow porous carbon (CoSA-HC). The cobalt single atoms can activate selenium reactivity and immobilize selenium and polyselenides. The as-prepared selenium-carbon (Se@CoSA-HC) cathodes deliver a high discharge capacity, a superior rate capability, and excellent cycling stability with a Coulombic efficiency of ~100%. This work could open an avenue for achieving long cycle life and high-power lithium-selenium batteries.

Tian, H, Zhang, C, Su, P, Shen, Z, Liu, H, Wang, G, Liu, S & Liu, J 2020, 'Metal-organic-framework-derived formation of Co–N-doped carbon materials for efficient oxygen reduction reaction', Journal of Energy Chemistry, vol. 40, pp. 137-143.
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© 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences Non-precious metal nitrogen-doped carbonaceous materials have attracted tremendous attention in the field of electrochemical energy storage and conversion. Herein, we report the designed synthesis of a novel series of Co-N-C nanocomposites and their evaluation of electrochemical properties. Novel yolk-shell structured Co nanoparticles@polymer materials are fabricated from the facile coating polymer strategy on the surface of ZIF-67. After calcination in nitrogen atmosphere, the Co–N–C nanocomposites in which cobalt metal nanoparticles are embedded in the highly porous and graphitic carbon matrix are successfully achieved. The cobalt nanoparticles containing cobalt metal crystallites with an oxidized shell and/or smaller (or amorphous) cobalt-oxide deposits appear on the surface of graphitic carbons. The prepared Co–N–C nanoparticles showed favorable electrocatalytic activity for oxygen reduction reactions, which is attributed to its high graphitic degree, large surface area and the large amount existence of Co–N active sites.

Tian, H, Zhao, J, Wang, X, Wang, L, Liu, H, Wang, G, Huang, J, Liu, J & Lu, GQM 2020, 'Construction of hollow mesoporous silica nanoreactors for enhanced photo-oxidations over Au-Pt catalysts', National Science Review, vol. 7, no. 11, pp. 1647-1655.
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Abstract It is highly desirable to design hollow structures with multi-scale functions by mimicking cells for the construction of micro/nanoreactors. Herein, we report the construction of hollow-structured submicrometer-photoreactors with bimetallic catalysts loaded within mesoporous silicas. The synthesis parameters are optimized to study the evolution of hollow structure through hydrothermal treatment and an ‘adhesive-contraction’ formation mechanism is proposed. AuPt@HMZS catalysts exhibited a broader absorbance region under visible light and the adsorption edge displayed a red-shift, indicating the strong metal–metal interactions at the alloy interface. The reaction performance of the coupled Au-Pt catalysts can be tuned to achieve excellent catalytic activity in cinnamyl alcohol oxidation to cinnamic acid for 3.1 mmol g−1 with 99% selectivity. The proposed strategy to build hollow structures as multifunctional micro/nanoreactors is promising for the design of high-performance and sustainable catalysts for chemical synthesis.

Tkacheva, A, Zhang, J, Sun, B, Zhou, D, Wang, G & McDonagh, AM 2020, 'TEMPO-Ionic Liquids as Redox Mediators and Solvents for Li–O₂ Batteries', The Journal of Physical Chemistry C, vol. 124, no. 9, pp. 5087-5092.
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Copyright © 2020 American Chemical Society. Effective Li-O2 batteries require additives to suppress the side reactions and the increase in charge potential at the oxygen cathode, which leads to an inevitable battery failure. In this study, two families of new 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-substituted imidazolium ionic liquids (TEMPOImILs) were synthesized, and their properties were examined to determine the optimal structures that function as both solvents and redox mediators in Li-O2 batteries. Comparison of the characteristics revealed that batteries with TEMPOImILs bearing a hydrogen rather than a methyl substituent in the 2-position of the imidazole moiety had a longer cycle life, whereas the length of the alkyl chain connecting the imidazole ring and 4-hydroxy-TEMPO did not have any substantial effect on the battery performance.

Trujillo Uruena, M, York, R, Philp, M, Kuzhiumparambil, U, Wei, Z, Yun, K & Fu, S 2020, 'Identification of Unique 4-Methylmethcathinone (4-MMC) Degradation Markers in Putrefied Matrices†', Journal of Analytical Toxicology, vol. 44, no. 8, pp. 803-810.
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Abstract Drug degradation as a consequence of putrefactive bacterial activity is a well-known factor that affects the identification and quantitation of certain substances of forensic interest. Current knowledge on putrefaction-mediated degradation of drugs is, however, significantly lacking. This study aimed to investigate the degradation of 4-methylmethcathinone (4-MMC or mephedrone) and to detect its degradation products in putrefied biological matrices containing 4-MMC. The bacteria species Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Proteus vulgaris were grown in brain-heart infusion broth, spiked with 4-MMC and incubated at 37°C for 24 h. Postmortem human blood and fresh porcine liver macerate were also left to putrefy in sample tubes at room temperature for 1 week. Structural elucidation was based on modern spectroscopic analyses including the use of high-resolution mass spectrometry and nuclear magnetic resonance spectroscopy. All four putrefactive bacteria were capable of degrading 4-MMC extensively under the experimental conditions explored. Of particular interest was the discovery of a novel degradation product common to all four bacterial species, which was assigned as 2-hydroxy-1-(4-methylphenyl)propan-1-one (HMP) based on the spectroscopic data. This degradation product was detectable in both postmortem human blood and porcine liver samples. The stability of the identified degradation products, especially HMP, should be further investigated to assess their validity of serving as marker analytes for monitoring 4-MMC in postmortem toxicology.

Wang, M, Xu, W, Yang, C, Qiu, H & Zhu, J 2020, 'Analytical Calculation of No-Load Magnetic Field in Permanent Magnet Linear Synchronous Motors Based on an Accurate Subdomain Model', Diangong Jishu Xuebao/Transactions of China Electrotechnical Society, vol. 35, no. 5, pp. 942-953.
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Accurate calculation of the magnetic field distribution in permanent magnet linear synchronous motor (PMLSM) is required to obtain the parameters and performance, and the establishment of an accurate mathematical model is the key to solving the magnetic field problem. To avoid the limitations of the traditional analytical theory of PMLSM in solving the slot effect on air gap magnetic field, an accurate subdomain model of PMLSM is proposed to obtain the accurate magnetic field distribution. By taking into account the relative magnetic permeability of the permanent magnet (PM), slot depth and mutual influence of all slots on the magnetic field distribution, the Laplace equation of permanent magnet subdomain, airgap subdomain and slot subdomain are established in the scalar magnetic potential. According to the boundary conditions of each subdomain interface, all boundary condition equations are set up based on the Fourier series method, and the equivalent model of end area is established. The scalar magnetic potential and no-load flux density distribution of each subdomain are then solved. The slot and end effects on the spatial distribution of air gap magnetic field are discussed. The accuracy of analytical model is validated by the finite element method (FEM) results.

Wang, S, Liu, C, Wang, Y, Lei, G, Guo, Y & Zhu, J 2020, 'Electromagnetic performance analysis of flux-switching permanent magnet tubular machine with hybrid cores', CES Transactions on Electrical Machines and Systems, vol. 4, no. 1, pp. 43-52.
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Wang, S, Ma, J, Liu, C, Wang, Y, Lei, G, Guo, Y & Zhu, J 2020, 'Design and performance analysis of a novel synchronous reluctance machine', International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 2, pp. 249-265.
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© 2020 - IOS Press and the authors. All rights reserved. To improve output torque ability and reduce torque ripple in traditional synchronous reluctance motor (TSynRM), a new synchronous reluctance motor (NSynRM) is proposed in this paper. The rotor of NSynRM is composed of both grain-oriented silicon steel and non-oriented silicon steel. With the reasonable design of rotor structure, the torque of NSynRM has been improved and its torque ripple has been reduced greatly. Firstly, TSynRM and NSynRM are qualitatively compared by using the magnetic network method. Secondly, the main parameters of these two machines are optimized by using finite element method (FEM). Then the performance comparison between two optimized machines are carried out. Finally, the equivalent stress of these two machines at the maximum speed are analyzed. It can be seen that NSynRM can have 6.8% higher torque under rated load, 8% higher torque under maximum load, 17.5% wider constant torque operation region, and lower torque ripple compared with the TSynRM.

Wang, S, Wang, Y, Liu, C, Lei, G, Zhu, J & Guo, Y 2020, 'Detent Force Minimization of a Tubular Flux-Switching Permanent Magnet Motor Using Un-Equal Width Stator Slots Based on Taguchi Method', IEEE Transactions on Applied Superconductivity, vol. 30, no. 4, pp. 1-5.
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Wang, T, Li, Y, Zhang, J, Yan, K, Jaumaux, P, Yang, J, Wang, C, Shanmukaraj, D, Sun, B, Armand, M, Cui, Y & Wang, G 2020, 'Immunizing lithium metal anodes against dendrite growth using protein molecules to achieve high energy batteries', Nature Communications, vol. 11, no. 1.
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AbstractThe practical applications of lithium metal anodes in high-energy-density lithium metal batteries have been hindered by their formation and growth of lithium dendrites. Herein, we discover that certain protein could efficiently prevent and eliminate the growth of wispy lithium dendrites, leading to long cycle life and high Coulombic efficiency of lithium metal anodes. We contend that the protein molecules function as a “self-defense” agent, mitigating the formation of lithium embryos, thus mimicking natural, pathological immunization mechanisms. When added into the electrolyte, protein molecules are automatically adsorbed on the surface of lithium metal anodes, particularly on the tips of lithium buds, through spatial conformation and secondary structure transformation from α-helix to β-sheets. This effectively changes the electric field distribution around the tips of lithium buds and results in homogeneous plating and stripping of lithium metal anodes. Furthermore, we develop a slow sustained-release strategy to overcome the limited dispersibility of protein in the ether-based electrolyte and achieve a remarkably enhanced cycling performance of more than 2000 cycles for lithium metal batteries.

Wang, T, Su, D, Chen, Y, Yan, K, Yu, L, Liu, L, Zhong, Y, Notten, PHL, Wang, C & Wang, G 2020, 'Biomimetic 3D Fe/CeO2 decorated N-doped carbon nanotubes architectures for high-performance lithium-sulfur batteries', Chemical Engineering Journal, vol. 401, pp. 126079-126079.
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© 2020 Elsevier B.V. lithium-sulfur (Li-S) batteries have been regarded as one of the most promising systems for next-generation rechargeable batteries owing to their high energy density and low cost. However, the “Shuttle effect” of polysulfides and low sulfur utilization upon cycling are still hindering their practical applications. Herein, we report a series of marine organism-like hollow nanoarchitecture consisting of nitrogen (N) doped 1D carbon nanotubes (CNTs), which were derived from binary Fe/Ce Prussian blue analogs (PBAs) and melamine. This nitrogen-doped 3D hollow scaffold offers large inner space (ф ≈ 200 nm) and sufficient electric conducting for insulating sulfur and provides adsorption sites for immobilizing polysulphides. The introduced double metal species enable strong chemical adsorption toward polysulfides and could facilitate the redox reaction between sulfur and polysulphides. When applied in Li-S batteries, the as-prepared materials showed a high capacity of 1241 mAh g−1 and a stable cycling performance (1003 mAh g−1 after 100 cycles) at a current density of 0.2 C. The enhancement of electrochemical activity could be attributed to the 3D hollow architecture of the hybrid, in which the nitrogen-doping generates defects and active sites for improved interfacial adsorption. This work could inspire developing biomimetic architectures for high-performance Li-S batteries.

Wang, Y, Zhou, D, Palomares, V, Shanmukaraj, D, Sun, B, Tang, X, Wang, C, Armand, M, Rojo, T & Wang, G 2020, 'Revitalising sodium–sulfur batteries for non-high-temperature operation: a crucial review', Energy & Environmental Science, vol. 13, no. 11, pp. 3848-3879.
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We review the working mechanisms, opportunity and challenges of intermediate-temperature and room-temperature sodium–sulfur batteries for low-cost energy storage.

Wu, H, Tian, H, Li, J, Liu, L, Wang, Y, Qiu, J, Wang, S & Liu, S 2020, 'Self-detoxifying hollow zinc silica nanospheres with tunable Ag ion release-recapture capability: A nanoantibiotic for efficient MRSA inhibition', Composites Part B: Engineering, vol. 202, pp. 108415-108415.
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© 2020 Elsevier Ltd Nanoparticle-enabled strategies to combat antimicrobial-resistant (AMR) bacteria are highly demanded, which hopefully can overcome the barriers associated with conventional antibiotics to achieve high therapeutic efficacy by improving pharmacokinetics. Here, we report the controlled fabrication of multiple Ag nanoparticles (AgNPs) containing ZIF-8 derived hollow -Zn-O-Si- nanospheres with mesoporous wall, Ag&Zn@mesSiO2, which can release and recapture Ag+ ions, thus, efficiently eradicate planktonic methicillin-resistant Staphylococcus aureus (MRSA) in vivo. The AgNPs encapsulated inside the large internal cavities of the hollow structure can kill MRSA at significantly reduced dosages due to the synergistic effect of released Zn and Ag ions, which was 10 times lower in comparison with single Ag+ application. The boomerang-like release-and-recapture scheme of the Ag+ ions helps to greatly reduce the notorious Ag toxicity. Such novel structured nanocomposites with widened Ag therapeutic window possess great potential as nanoantibiotic for tackling MRSA infection.

Wu, T, Feng, Z, Wu, C, Lei, G, Guo, Y, Zhu, J & Wang, X 2020, 'Multiobjective Optimization of a Tubular Coreless LPMSM Based on Adaptive Multiobjective Black Hole Algorithm', IEEE Transactions on Industrial Electronics, vol. 67, no. 5, pp. 3901-3910.
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© 1982-2012 IEEE. In most multiobjective optimization problems of electrical machines, the weighted function method is used to convert them into single-objective optimization problems. This paper applies a kind of new multiobjective evolutionary algorithms (MOEAs), called adaptive multiobjective black hole (AMOBH) algorithms, to achieve effective multiobjective optimization of a tubular coreless linear permanent magnet synchronous motor (LPMSM). To reduce the computation cost of the MOEAs, a one-layer analytical model (AM) is presented for the tubular coreless LPMSM in this paper. The accuracy of the simplified one-layer AM is verified by comparisons with multilayer AM and finite element analysis (FEA) under different structure parameters. It is found that the simplified AM has good accuracy and can decrease the computation cost significantly. AMOBH algorithm is subsequently introduced. The optimal Pareto front with regard to thrust, copper loss, and permanent magnet volume are analyzed, and more diversified optimization results are provided. The final Pareto solution can be selected directly by practical physical values according to the application requirements. Finally, a prototype is fabricated for the selected design; its experimental results are provided and compared with those of the FEA results.

Xiong, H, Wang, Y, Fu, H, Liu, J & Zhu, J 2020, 'An Energy Efficient Excitation Source for Transcranial Magnetic Stimulation with Controllable Pulse Width', Diangong Jishu Xuebao/Transactions of China Electrotechnical Society, vol. 35, no. 4, pp. 679-686.
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In order to improve the energy saving rate of the excitation source, based on cTMS1, a novel energy efficient excitation source topology is proposed and the EEES circuit structure and switch control method are designed in this paper. Firstly, the pulse width is adjusted by controlling the on-time of the switch. Then the circuit topology is designed to realize energy recovery and reuse, which can improve the energy utilization of the system. Finally, the EEES experimental platform is built to verify the system performance. The experimental results demonstrate that the EEES can generate current pulses up to 1 058A with an adjustable pulse range of 5~160μs. Compared with the cTMS1 excitation source, the energy self-loss rate is obviously lower than cTMS1, and the energy saving rate of EEES is as high as 62.60%~93.21%. Therefore, the EEES system proposed in this paper provides an important reference for the development of TMS excitation source.

Xiong, P, Sun, B, Sakai, N, Ma, R, Sasaki, T, Wang, S, Zhang, J & Wang, G 2020, '2D Superlattices for Efficient Energy Storage and Conversion', Advanced Materials, vol. 32, no. 18, pp. 1902654-1902654.
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Abstract2D genuine unilamellar nanosheets, that are, the elementary building blocks of their layered parent crystals, have gained increasing attention, owing to their unique physical and chemical properties, and 2D features. In parallel with the great efforts to isolate these atomic‐thin crystals, a unique strategy to integrate them into 2D vertically stacked heterostuctures has enabled many functional applications. In particular, such 2D heterostructures have recently exhibited numerous exciting electrochemical performances for energy storage and conversion, especially the molecular‐scale heteroassembled superlattices using diverse 2D unilamellar nanosheets as building blocks. Herein, the research progress in scalable synthesis of 2D superlattices with an emphasis on a facile solution‐phase flocculation method is summarized. A particular focus is brought to the advantages of these 2D superlattices in applications of supercapacitors, rechargeable batteries, and water‐splitting catalysis. The challenges and perspectives on this promising field are also outlined.

Xiong, P, Zhang, F, Zhang, X, Wang, S, Liu, H, Sun, B, Zhang, J, Sun, Y, Ma, R, Bando, Y, Zhou, C, Liu, Z, Sasaki, T & Wang, G 2020, 'Strain engineering of two-dimensional multilayered heterostructures for beyond-lithium-based rechargeable batteries', Nature Communications, vol. 11, no. 1.
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AbstractBeyond-lithium-ion batteries are promising candidates for high-energy-density, low-cost and large-scale energy storage applications. However, the main challenge lies in the development of suitable electrode materials. Here, we demonstrate a new type of zero-strain cathode for reversible intercalation of beyond-Li+ ions (Na+, K+, Zn2+, Al3+) through interface strain engineering of a 2D multilayered VOPO4-graphene heterostructure. In-situ characterization and theoretical calculations reveal a reversible intercalation mechanism of cations in the 2D multilayered heterostructure with a negligible volume change. When applied as cathodes in K+-ion batteries, we achieve a high specific capacity of 160 mA h g−1 and a large energy density of ~570 W h kg−1, presenting the best reported performance to date. Moreover, the as-prepared 2D multilayered heterostructure can also be extended as cathodes for high-performance Na+, Zn2+, and Al3+-ion batteries. This work heralds a promising strategy to utilize strain engineering of 2D materials for advanced energy storage applications.

Xu, G, Yu, D, Zheng, D, Wang, S, Xue, W, Cao, XE, Zeng, H, Xiao, X, Ge, M, Lee, W-K & Zhu, M 2020, 'Fast Heat Transport Inside Lithium-Sulfur Batteries Promotes Their Safety and Electrochemical Performance', iScience, vol. 23, no. 10, pp. 101576-101576.
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Lithium-sulfur batteries are paid much attention owing to their high specific capacity and energy density. However, their practical applications are impeded by poor electrochemical performance due to the dissolved polysulfides. The concentration of soluble polysulfides has a linear relationship with the internal heat generation. The issue of heat transport inside lithium-sulfur batteries is often overlooked. Here, we designed a functional separator that not only had a high thermal conductivity of 0.65 W m-1 K-1 but also alleviated the diffusion of dissolved active materials to the lithium anode, improving the electrochemical performance and safety issue. Lithium-sulfur batteries with the functional separator have a specific capacity of 1,126.4 mAh g-1 at 0.2 C, and the specific capacity can be remained up to 893.5 mAh g-1 after 100 cycles. Pouch Cells with high sulfur loading also showed a good electrochemical performance under a lean electrolyte condition of electrolyte/sulfur (E/S) = 3 μL mg-1.

Xu, J, Liu, K, Jin, Y, Sun, B, Zhang, Z, Chen, Y, Su, D, Wang, G, Wu, H & Cui, Y 2020, 'A Garnet‐Type Solid‐Electrolyte‐Based Molten Lithium−Molybdenum−Iron(II) Chloride Battery with Advanced Reaction Mechanism', Advanced Materials, vol. 32, no. 32, pp. e2000960-2000960.
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AbstractSolid‐electrolyte‐based molten‐metal batteries have attracted considerable attention for grid‐scale energy storage. Although ZEBRA batteries are considered one of the promising candidates, they still have the potential concern of metal particle growth and ion exchange with the β”‐Al2O3 electrolyte. Herein, a Li6.4La3Zr1.4Ta0.6O12 solid‐electrolyte‐based molten lithium−molybdenum−iron(II) chloride battery (denoted as Li−Mo−FeCl2) operated at temperature of 250 °C, comprising a mixture of Fe and LiCl cathode materials, a Li anode, a garnet‐type Li‐ion ceramic electrolyte, and Mo additive, is designed to overcome these obstacles. Different from conventional battery reaction mechanisms, this battery revolutionarily synchronizes the reversible Fe−Mo alloying−dealloying reactions with the delithiation−lithiation processes, meaning that the porous Mo framework derived from Fe−Mo alloy simultaneously suppresses the growth of pure Fe particles. By adopting a Li anode and a Li‐ion ceramic electrolyte, the corrosion problem between the cathode and the solid electrolyte is overcome. With similar battery cost ($12 kWh−1), the theoretical energy density of Li−Mo−FeCl2 battery surpasses that of a Na−FeCl2 ZEBRA battery over 25%, to 576 Wh kg−1 and 2216 Wh L−1, respectively. Experimental results further prove this cell has excellent cycling performance (472 mAh gLiCl−1 after 300 cycles, 50 mg active material) and strong tolerance against the overcharge−overdischarge (3−1.6 V) and freezing−thawing (25−250 °C) incidents.

Xu, J, Liu, K, Jin, Y, Sun, B, Zhang, Z, Chen, Y, Su, D, Wang, G, Wu, H & Cui, Y 2020, 'Solid Electrolytes: A Garnet‐Type Solid‐Electrolyte‐Based Molten Lithium−Molybdenum−Iron(II) Chloride Battery with Advanced Reaction Mechanism (Adv. Mater. 32/2020)', Advanced Materials, vol. 32, no. 32, pp. 2070242-2070242.
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Xu, W, Zhang, Y, Du, G, He, M, Zhu, J, Ning, L, Ye, C & Hua, W 2020, 'Design and Analysis of a Hybridly Excited Asymmetric Stator Pole Doubly Salient Machine', IEEE Transactions on Industry Applications, vol. 56, no. 3, pp. 2600-2611.
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Xu, X, Roseblade, A, Rawling, T & Ung, AT 2020, 'Antiproliferative activities of tricyclic amides derived from β-caryophyllene via the Ritter reaction against MDA-MB-231 breast cancer cells', RSC Medicinal Chemistry, vol. 11, no. 1, pp. 118-124.
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Tricyclic amides were successfully synthesised from β-caryophyllene via the Ritter reaction. Amides 3c and 6b inhibited proliferation of MDA-MB-231 cells. Compound 6b inhibited cell cycle progression and induced predominantly apoptotic cell death.

Yan, K, Zhao, S, Zhang, J, Safaei, J, Yu, X, Wang, T, Wang, S, Sun, B & Wang, G 2020, 'Dendrite-Free Sodium Metal Batteries Enabled by the Release of Contact Strain on Flexible and Sodiophilic Matrix', Nano Letters, vol. 20, no. 8, pp. 6112-6119.
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The formation of sodium (Na) dendrites during cycling has impeded the practical application of Na metal anodes. Herein, we developed a flexible graphene-based matrix, e.g., a porous reduced graphene oxide (PRGO) film, to support dendrite-free Na nucleation and plating, contributing to high-performance Na metal batteries. The PRGO film possessed outstanding merits of sodiophilicity and flexibility. The sodiophilic PRGO film enabled uniform Na nucleation in the initial electroplating stage. Furthermore, the flexible PRGO film with a small Young's modulus effectively alleviated the texture deformation of electrodeposited Na, leading to a compact and dendrite-free Na deposition layer. The well-maintained Na metal anodes on the PRGO film exhibited superior cyclability, high Coulombic efficiency, and improved energy density in both half-cell and full-cell testing. This work illustrates the great significance of mechanical properties of the supporting matrix for the Na electroplating, which provides a new strategy to develop high-performance dendrite-free Na metal batteries.

Yang, W, Zhao, J, Tian, H, Wang, L, Wang, X, Ye, S, Liu, J & Huang, J 2020, 'Solar‐Driven Carbon Nanoreactor Coupling Gold and Platinum Nanocatalysts for Alcohol Oxidations', Small, vol. 16, no. 30, pp. 2002236-2002236.
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AbstractThis research reports gold (Au) and platinum (Pt) nanocatalysts spatially confined in a porous carbon nanosphere as a new solar‐driven carbon nanoreactor (CNR). The CNRs have confined size (≈100 nm), high specific surface area, and high thermal and electrical conductivity. The black color of CNR can improve the energy harvest efficiency of the solar irradiation to thermal energy within each nanoreactor. The localized surface plasmon resonance (LSPR) on Au nanocatalysts‐induced electron oscillation causes the localized heating effect inside each CNR. Therefore, the heat will be accumulated in the confined space of CNR and transferred to reaction energy to drive the alcohol oxidation on uniformly dispersed Au and Pt nanoparticles inside the nanoreactor. The energetic electrons induced by LSPR effect on the surface of Au nanoparticles are transferred to the nearby and more active Pt surface via the conductive CNR, which strongly enhances the conversion of cinnamyl alcohol from 14% on Pt‐CNR up to 100% on AuPt‐CNR after a 3 h reaction. Therefore, the cooperative effect of Au and Pt nanoparticles confined in the CNRs utilized in this work can largely increase the efficiency of harvesting solar energy to drive the important chemical processes.

Yang, Y, Yang, Y, Pei, Z, Wu, K-H, Tan, C, Wang, H, Wei, L, Mahmood, A, Yan, C, Dong, J, Zhao, S & Chen, Y 2020, 'Recent Progress of Carbon-Supported Single-Atom Catalysts for Energy Conversion and Storage', Matter, vol. 3, no. 5, pp. 1442-1476.
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Yin, Y, Zhang, Y, Liu, N, Sun, B & Zhang, N 2020, 'Biomass-Derived P/N-Co-Doped Carbon Nanosheets Encapsulate Cu3P Nanoparticles as High-Performance Anode Materials for Sodium–Ion Batteries', Frontiers in Chemistry, vol. 8.
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© Copyright © 2020 Yin, Zhang, Liu, Sun and Zhang. Biomass-derived approaches have been accepted as a practical way for the design of transitional metal phosphides confined by carbon matrix (TMPs@C) as energy storage materials. Herein, we successfully synthesize P/N-co-doped carbon nanosheets encapsulating Cu3P nanoparticles (Cu3P@P/N-C) by a feasible aqueous reaction followed by a phosphorization procedure using sodium alginate as the biomass carbon source. Cu-alginate hydrogel balls can be squeezed into two-dimensional (2D) nanosheets through a freeze–drying process. Then, Cu3P@P/N-C was obtained after the phosphorization procedure. This rationally designed structure not only improved the kinetics of ion/electron transportation but also buffered the volume expansion of Cu3P nanoparticles during the continuous charge and discharge processes. In addition, the 2D P/N co-doped carbon nanosheets can also serve as a conductive matrix, which can enhance the electronic conductivity of the whole electrode as well as provide rapid channels for electron/ion diffusion. Thus, when applied as anode materials for sodium-ion batteries, it exhibited remarkable cycling stability and rate performance. Prominently, Cu3P@P/N-C demonstrated an outstanding reversible capacity of 209.3 mAh g−1 at 1 A g−1 after 1,000 cycles. Besides, it still maintained a superior specific capacity of 118.2 mAh g−1 after 2,000 cycles, even at a high current density of 5 A g−1.

Yousaf, M, Chen, Y, Tabassum, H, Wang, Z, Wang, Y, Abid, AY, Mahmood, A, Mahmood, N, Guo, S, Han, RPS & Gao, P 2020, 'A Dual Protection System for Heterostructured 3D CNT/CoSe₂/C as High Areal Capacity Anode for Sodium Storage', Advanced Science, vol. 7, no. 5, pp. 1902907-1902907.
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Abstract3D electrode design is normally opted for multiple advantages, however, instability/detachment of active material causes the pulverization and degradation of the structure, and ultimately poor cyclic stability. Here, a dually protected, highly compressible, and freestanding anode is presented for sodium‐ion batteries, where 3D carbon nanotube (CNT) sponge is decorated with homogeneously dispersed CoSe2 nanoparticles (NPs) which are protected under carbon overcoat (CNT/CoSe2/C). The 3D CNT sponge delivers enough space for high mass loading while providing high mechanical strength and faster conduction pathway among the NPs. The outer amorphous carbon overcoat controls the formation of solid electrolyte interphase film by avoiding direct contact of CoSe2 with electrolyte, accommodates large volume changes, and ultimately enhances the overall conductivity of cell and assists in transmitting electron to an external circuit. Moreover, the hybrid can be densified up to 11‐fold without affecting its microstructure that results in ultrahigh areal mass loading of 17.4 mg cm−2 and an areal capacity of 7.03 mAh cm−2 along with a high gravimetric capacity of 531 mAh g−1 at 100 mA g−1. Thus, compact and smart devices can be realized by this new electrode design for heavy‐duty commercial applications.

Yu, X, Yu, Z-Y, Zhang, X-L, Li, P, Sun, B, Gao, X, Yan, K, Liu, H, Duan, Y, Gao, M-R, Wang, G & Yu, S-H 2020, 'Highly disordered cobalt oxide nanostructure induced by sulfur incorporation for efficient overall water splitting', Nano Energy, vol. 71, pp. 104652-104652.
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© 2020 Exploitation of cost-efficient active electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) plays a significant role for scalable electricity-to-hydrogen energy conversion. Crystalline transition metal oxides as the promising non-noble catalysts, however, are often suffering from the large excess overpotential and unsatisfactory performance. To boost their intrinsic catalytic property, we report here an incorporation of electronegative sulfur into crystalline cobalt oxide (S-CoOx) to create structural disorder via a facile room-temperature ion exchange strategy. Compared with its crystalline form, the disorder in S-CoOx catalyst enables the increased low oxygen coordination and rich defect sites, which endows S-CoOx a superior catalytic activity for both OER and HER in alkali. Intriguingly, a water electrolyser adopting S-CoOx as both OER and HER electrode catalysts requires mere 1.63 V to reach a current density of 10 mA cm−2 in 1 M KOH. This work highlights the effectiveness of designing high-performing electrocatalysts for water electrolysers based on disordered structural materials.

Zakria, M, Bove, P, Rogers, DJ, Teherani, FH, Sandana, EV, Phillips, MR & Ton-That, C 2020, 'Chemical structure and optical signatures of nitrogen acceptors in MgZnO', Journal of Materials Chemistry C, vol. 8, no. 19, pp. 6435-6441.
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Nitrogen can be incorporated into MgZnO using low-temperature deposition. Donor–acceptor pair emission from N-doped MgZnO is attributed to molecular N₂.

Zhan, Y, Guo, Y, Zhu, J, Li, L, Yang, B & Liang, B 2020, 'A review on mitigation technologies of low frequency current ripple injected into fuel cell and a case study', International Journal of Hydrogen Energy, vol. 45, no. 46, pp. 25167-25190.
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Zhao, S, Dong, L, Sun, B, Yan, K, Zhang, J, Wan, S, He, F, Munroe, P, Notten, PHL & Wang, G 2020, 'K₂Ti₂O₅@C Microspheres with Enhanced K⁺ Intercalation Pseudocapacitance Ensuring Fast Potassium Storage and Long‐Term Cycling Stability', Small, vol. 16, no. 4, pp. 1906131-1906131.
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AbstractBenefiting from the natural abundance and low standard redox potential of potassium, potassium‐ion batteries (PIBs) are regarded as one of the most promising alternatives to lithium‐ion batteries for low‐cost energy storage. However, most PIB electrode materials suffer from sluggish thermodynamic kinetics and dramatic volume expansion during K+ (de)intercalation. Herein, it is reported on carbon‐coated K2Ti2O5 microspheres (S‐KTO@C) synthesized through a facile spray drying method. Taking advantage of both the porous microstructure and carbon coating, S‐KTO@C shows excellent rate capability and cycling stability as an anode material for PIBs. Furthermore, the intimate integration of carbon coating through chemical vapor deposition technology significantly enhances the K+ intercalation pseudocapacitive behavior. As a proof of concept, a potassium‐ion hybrid capacitor is constructed with the S‐KTO@C (battery‐type anode material) and the activated carbon (capacitor‐type cathode material). The assembled device shows a high energy density, high power density, and excellent capacity retention. This work can pave the way for the development of high‐performance potassium‐based energy storage devices.

Zhou, D, Tang, X, Guo, X, Li, P, Shanmukaraj, D, Liu, H, Gao, X, Wang, Y, Rojo, T, Armand, M & Wang, G 2020, 'Polyolefin‐Based Janus Separator for Rechargeable Sodium Batteries', Angewandte Chemie, vol. 132, no. 38, pp. 16868-16877.
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AbstractRechargeable sodium batteries are a promising technology for low‐cost energy storage. However, the undesirable drawbacks originating from the use of glass fiber membrane separators have long been overlooked. A versatile grafting–filtering strategy was developed to controllably tune commercial polyolefin separators for sodium batteries. The as‐developed Janus separators contain a single–ion‐conducting polymer‐grafted side and a functional low‐dimensional material coated side. When employed in room‐temperature sodium–sulfur batteries, the poly(1‐[3‐(methacryloyloxy)propylsulfonyl]‐1‐(trifluoromethanesulfonyl)imide sodium)‐grafted side effectively enhances the electrolyte wettability, and inhibits polysulfide diffusion and sodium dendrite growth. Moreover, a titanium‐deficient nitrogen‐containing MXene‐coated side electrocatalytically improved the polysulfide conversion kinetics. The as‐developed batteries demonstrate high capacity and extended cycling life with lean electrolyte loading.

Zhu, LF, Zhu, TL, Yu, SB, Han, XY & Zhu, JG 2020, 'Analytical approach for calculation of eddy current losses in magnets caused by permeance harmonics in air gap', Dianji yu Kongzhi Xuebao/Electric Machines and Control, vol. 24, no. 5.
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The three dimensional finite element analysis of eddy current losses in magnets is time consuming, the accurate analytical methods of eddy current losses in magnets are complicated and the relationship between parameters and performances cannot be shown clearly. The coordinate was rebuilt in the slot location, and the local analysis model was investigated. The variation of flux density in magnet at the slot position was analyzed and idealized, a simplified analytical calculation method of eddy current losses in magnets caused by the permeance harmonics in the air gap was proposed, by which the main influence factors are exhibited obviously, and the calculation time is short. The calculated results of eddy current losses in magnets caused by the permeance harmonics were verified by the three dimensional finite element calculation results and the measured results. The influence factors for the variation of magnet flux density are the slot opening width to the equivalent air gap length and to the tooth pitch, and the influences of relative parameters to the eddy current losses in magnets caused by the permeance harmonics were analyzed, and the optimization method was adopted based on the analytical results. It shows that, the eddy current losses in magnets are decreased by about 90.2 percent.

Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH₄ from its Hydrolytic Product', Angewandte Chemie, vol. 132, no. 22, pp. 8701-8707.
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AbstractSodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.

Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Closing the Loop for Hydrogen Storage: Facile Regeneration of NaBH₄ from its Hydrolytic Product', Angewandte Chemie International Edition, vol. 59, no. 22, pp. 8623-8629.
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AbstractSodium borohydride (NaBH4) is among the most studied hydrogen storage materials because it is able to deliver high‐purity H2 at room temperature with controllable kinetics via hydrolysis; however, its regeneration from the hydrolytic product has been challenging. Now, a facile method is reported to regenerate NaBH4 with high yield and low costs. The hydrolytic product NaBO2 in aqueous solution reacts with CO2, forming Na2B4O7⋅10 H2O and Na2CO3, both of which are ball‐milled with Mg under ambient conditions to form NaBH4 in high yield (close to 80 %). Compared with previous studies, this approach avoids expensive reducing agents such as MgH2, bypasses the energy‐intensive dehydration procedure to remove water from Na2B4O7⋅10 H2O, and does not require high‐pressure H2 gas, therefore leading to much reduced costs. This method is expected to effectively close the loop of NaBH4 regeneration and hydrolysis, enabling a wide deployment of NaBH4 for hydrogen storage.

Zhu, Y, Ouyang, L, Zhong, H, Liu, J, Wang, H, Shao, H, Huang, Z & Zhu, M 2020, 'Efficient Synthesis of Sodium Borohydride: Balancing Reducing Agents with Intrinsic Hydrogen Source in Hydrated Borax', ACS Sustainable Chemistry & Engineering, vol. 8, no. 35, pp. 13449-13458.
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© 2020 American Chemical Society. Sodium borohydride (NaBH4) has been identified as one of the most promising hydrogen storage materials; however, it is still challenging to produce NaBH4 with low cost and high efficiency, which are largely determined by the sources of boron and hydrogen and reducing agents used. Herein, we report an economical method to produce NaBH4 by ball milling hydrated borax (Na2B4O7·10H2O and/or Na2B4O7·5H2O) with different reducing agents such as MgH2, Mg, and NaH under ambient conditions. The direct use of natural hydrated borax avoids the dehydration process (at 600 °C) and consequently reduces cost and improves overall energy efficiency. A high yield of 93.1% can be achieved for a short ball mill duration (3.5 h) for Na2B4O7·5H2O-NaH-MgH2 system. In this system, H2 is generated in situ which subsequently reacts with Mg forming MgH2. Low cost Mg is therefore employed to replace the majority of MgH2, leading to an attractive yield of 78.6%. To further reduce the cost of raw materials and improve the utilization of hydrogen source in the hydrated borax, Na2B4O7·10H2O is used to partially substitute for Na2B4O7·5H2O, leading to a complete replacement of MgH2. Compared with literature results, the optimized recipe features low cost and high efficiency since it utilizes hydrogen from the hydrated water in natural borax and avoids high temperatures. Our finding is expected to facilitate applications of NaBH4 for hydrogen storage.

Zou, J, Xu, W, Zhu, J & Liu, Y 2020, 'Simplified Model Predictive Thrust Control Based Arbitrary Two Voltage Vectors for Linear Induction Machines in Metro Transportation', IEEE Transactions on Vehicular Technology, vol. 69, no. 7, pp. 7092-7103.
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Al-Soeidat, M, Khawaldeh, H, Lu, DD-C & Zhu, J 1970, 'A Novel High Step-up Three-Port Bidirectional DC/DC Converter for PV-Battery Integrated System', 2020 IEEE Applied Power Electronics Conference and Exposition (APEC), 2020 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE, New Orleans, LA, USA, pp. 3352-3357.
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In this paper, a new high step-up non-isolated three- port DC-DC converter (HS-NITPC) is proposed. The converter is designed to integrate a solar panel with battery storage in order to boost its voltage, reduce the effect of solar energy intermittency and enhance solar power performance under unpredictable load demand. The converter combines three converters to form one integrated converter by sharing some components. Thus, the converter has high power density and fewer components compared to the traditional DC-DC converters. The coupled inductor is used to achieve a high output regulated voltage, transfer energy among the ports and facilitate maximum power point tracking for the solar panel. A hardware prototype was built and tested to verify the proposed circuit for 180 W input power. The proposed converter is suitable for stand-alone or grid- connected solar system. Moreover, it could be used in the electric vehicle where the regenerative braking is used.

Diao, K, Sun, X, Lei, G, Guo, Y & Zhu, J 1970, 'Application-Oriented System Level Optimization Method for Switched Reluctance Motor Drive Systems', 2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia), 2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia), IEEE, Nanjing, China, pp. 473-477.
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This paper presents a novel application-oriented system level optimization method for switched reluctance motor (SRM) drive systems. First, the multiobjective optimization model is defined according to the design requirements. Then, all the parameters of the motor and controller are divided into three subspaces according to the sensitivity results on the defined objectives. Finally, the optimization of each subspace is performed sequentially by using the approximate models and advanced genetic algorithm, and the best solution can be selected from the Pareto optimal solutions. To verify the effectiveness of the proposed method, an SRM drive system with a segmented-rotor SRM and the angle position control method is investigated. This is a high-dimensional system level optimization problem with ten parameters. The computational cost can be greatly reduced without the sacrifice of accuracy. From the discussion, it can be found that the proposed multiobjective system level optimization method can achieve high efficiency and low torque ripple. Besides, it provides alternative solutions for applications with different output power demands.

Khan, SA, Noman Habib Khan, M, Guo, Y, Siwakoti, YP & Zhu, J 1970, 'A novel five-level switched capacitor type inverter topology for grid-tied photovoltaic application', 2020 IEEE Applied Power Electronics Conference and Exposition (APEC), 2020 IEEE Applied Power Electronics Conference and Exposition (APEC), IEEE, New Orleans, LA, USA.
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This paper presents a novel five-level inverter topology and associated control scheme. The proposed structure consists of a capacitor and eight active switching elements. It requires only one dc source and is capable of generating five voltage levels with double voltage boosting gain. On the other hand, it does not require any control scheme to balance the capacitor in the DC-bus due to inherent voltage balancing capability. As a result, the control complexity reduces a lot. Brief analysis followed by simulation and measurement results of a proposed 5-level inverter using the finite control set model predictive control (FCS-MPC) algorithm is presented. Detail of the analysis with more measurement result and comparison will be presented in the final paper.

Kiran, MR, Farrok, O, Islam, MR, Zhu, J, Kouzani, AZ & Mahmud, MAP 1970, 'Characterization of a High Frequency Transformer with HTS Winding and Amorphous Magnetic Core for Power Converter Application', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE.
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Power converter with high frequency transformers (HFTs) are being widely used in the field of electric vehicle, switching mode power supply, renewable energy sectors including oceanic wave energy converter and so on. This paper proposes an improved compact design of a 4.75 kW, 100 kHz superconducting HFT that would offer size minimization facilities of power converters. Yttrium barium copper oxide (YBCO) material-based superconductor is used for maximum power transfer analysis. The proposed superconducting winding is compact which would minimize the thermal limitation and proximity effect. The proposed HFT is characterized for using the conventional and advanced magnetic materials with gapped and ungapped structures. Gapped toroidal core structure of HFT offers improved capability of withstanding de bias magnetizing current which occurs in many cases including isolation. Simulation results show the comparison of magnetic flux density, core loss, and power including air gap effect. YBCO windings based HFT contributes to transfer approximately 11.76% more power compared to that of using the copper winding.

Li, M, Yang, Y, Zhang, Y, Iacopi, F, Ram, S & Nulman, J 1970, 'A Fully Integrated Conductive and Dielectric Additive Manufacturing Technology for Microwave Circuits and Antennas', 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC), 15th European Microwave Integrated Circuits Conference (EuMIC) / 50th European Microwave Conference (EuMC), IEEE, ELECTR NETWORK.

Li, M, Yang, Y, Zhang, Y, Iacopi, F, Ram, S & Nulman, J 1970, 'A Fully Integrated Conductive and Dielectric Additive Manufacturing Technology for Microwave Circuits and Antennas', 2020 50TH EUROPEAN MICROWAVE CONFERENCE (EUMC), 15th European Microwave Integrated Circuits Conference (EuMIC) / 50th European Microwave Conference (EuMC), IEEE, ELECTR NETWORK, pp. 392-395.

Li, Y, Li, Y, Liu, C, Zhu, L, Zhu, J & Lei, G 1970, 'Numerical Calculation for Power Transformer Vibration Based on Dynamic Magnetostriction Model', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE.
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Liu, L, Guo, Y, Lei, G, Zhu, J & Jin, J 1970, 'Power Loss Analysis of High Speed Permanent Magnet Machine', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE, China, pp. 1-2.
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Concerns about advantages such as high efficiency, high power density, small size, light weight, and fast dynamic response have contributed to the increasing industrial application of high speed permanent magnet machines (HSPMMs). Aiming at the complex power loss situations due to high operating speed and frequency, in this paper, the calculation models of HSPMM in terms of iron loss and copper loss are reviewed based on the thoroughly overview of previous research outcomes. Moreover, the research status and future directions about HSPMM power loss analysis are illustrated, which may provide a strong reference for the design and optimization of electrical drive systems with HSPMMs.

Nguyen, D-A, Tran, X-T, Dang, KN & Iacopi, F 1970, 'A lightweight Max-Pooling method and architecture for Deep Spiking Convolutional Neural Networks', 2020 IEEE Asia Pacific Conference on Circuits and Systems (APCCAS), 2020 IEEE Asia Pacific Conference on Circuits and Systems (APCCAS), IEEE.
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Rufangura, P, Agrawal, A, Bosi, M, Folland, TG, Caldwell, JD & Iacopi, F 1970, 'Enhanced Mid -Infrared Reflectance with Graphene Coated Silicon Carbide Nanowires', 14th Pacific Rim Conference on Lasers and Electro-Optics (CLEO PR 2020), Conference on Lasers and Electro-Optics/Pacific Rim, Optica Publishing Group.
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The mid-infrared optical spectrum hosts a variety of promising photonic applications. Herein we simulate and experimentally demonstrate reflectance enhancement of MIR light using graphene-coated silicon carbide nanowires on silicon, showing promise for on-chip MIR nanophotonics.

Wang, J, Jin, J, Zhu, J, Guo, Y & Xing, Y 1970, 'Unified Control of APF and SMES Based on Fuzzy Logic Control', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE, China, pp. 1-2.
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This paper proposes two single closed-loop control methods to achieve unified control of active power filter (APF) and superconducting magnetic energy storage (SMES). For the DC-DC chopper circuit, this paper proposes a fuzzy logic control (FLC) method to achieve the stabilization of the DC link voltage and the charge and discharge control of the SMES coil. For the back-stage DC-AC converter circuit, hysteresis current method realizes tracking control of reference current. The control method enables the SMES device to not only implement active filtering but also to suppress the active power oscillation of the system caused by sudden load changes. The simulation model of the whole system was built by Matlab/Simulink for verification analysis.

Yang, H, Huang, P, Zhang, Y & Zhu, J 1970, 'Model Predictive Flux Control Based on Synchronous Pulse-Width Modulation', 2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020 IEEE Energy Conversion Congress and Exposition (ECCE), IEEE, USA, pp. 2701-2707.
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The switching frequency of the high-power traction drive is relatively low, and the wide speed range results in a large variation of carrier ratio. Therefore, a hybrid pulse width modulation (PWM) strategy needs to be designed to meet the requirements over the full speed operation. In this paper, the torque control of induction motor drives under low switching frequency is investigated. Combining synchronized space vector PWM schemes with the model predictive flux control, a control strategy is developed that does not require phase compensation of the voltage reference and smooth transition between different PWM modes is achieved. Simulation, hardware-in-the-loop and experimental tests validate the effectiveness of the developed method.

Zhang, R, Jin, J, Zhu, J, Guo, Y & Abu-Siada, A 1970, 'Numerical Study on Electromagnetic Field and AC loss of HTS Air-core Transformer', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE, China, pp. 1-2.
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Air-core transformer has advantages of no iron loss, no magnetic saturation, and compact in size, which make them attractive to be studied for practical applications. In this paper, the H-formulation is used to numerically analyze the electromagnetic field and AC loss of the HTS air-core transformer and optimize the air gap.

Zuo, Y, Xiao, M, Song, Y, Li, Y, Li, Y & Zhu, J 1970, 'Modeling and Finite Element Calculation of Core Loss in Anode Saturable Reactor Based on JA Dynamic Hysteresis Model', 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), 2020 IEEE International Conference on Applied Superconductivity and Electromagnetic Devices (ASEMD), IEEE, China, pp. 1-2.
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Anode saturable reactor is an important part of HVDe converter valve. The surge current causes core losses and temperature rising during the transient processes of thyristors. In this paper, to investigate the single core loss of anode saturable reactor, the theoretical calculation and electromagnetic simulation are carried out with the actual surge current. The Jiles-Atherton(J-A) dynamic hysteresis model integrating hysteresis, eddy current, and excess losses is considered for accurate computation of core losses. The model is incorporated into the finite element method to investigate the loss distribution in the core of anode saturable reactor.

Huynh, TT, Chikoidze, E, Irvine, CP, Zakria, M, Dumont, Y, Teherani, FH, Sandana, EV, Bove, P, Rogers, DJ, Phillips, MR & Ton-That, C 2020, 'Red Luminescence in H-doped beta-Ga2O3'.

Huynh, TT, Lem, LLC, Kuramata, A, Phillips, MR & Ton-That, C 2020, 'Kinetics of charge carrier recombination in beta-Ga2O3 crystals'.