Top-level design pattern of PM-assisted synchronous reluctance machines

The main challenge of the PM-assisted synchronous reluctance machine (PMASynRM) design is to determine numerous parameters for the requirement of multi-objectives. According to the top-level design concept, the optimization for PMASynRMs can be regarded as multi-parameter and multi-objective optimization problems (MOOPs). In this paper, the high-dimensional optimization problem is transformed into two low-dimensional optimization sub-problems. The analytical model algorithm has been established to solve the first sub-problem. Then, the optimization algorithms including the particle swarm optimization (PSO), the standard genetic algorithm (GA) with elitist strategy, and the pattern search (PS) are used for the second sub-problem. It is revealed that the optimization with PS algorithm is superior, in aspects of optimized machine performance and optimization efficiency, compared with that of PSO and GA algorithms. Furthermore, four PMASynRMs have been optimized with the developed process coupled 2D-FEA simulation, and significant performance improvement has been achieved after optimization. Finally, a 7.5kW@3 000r/min prototype machine is manufactured and tested to validate the top-level design pattern.This work was supported by the Natural Science Foundation of China under the grants of 51837010 and 51690182

Anion Texturing Towards Dendrite‐Free Zn Anode for Aqueous Rechargeable Batteries

The reversibility of metal anode is a fundamental challenge to the lifetime of rechargeable batteries. Though being widely employed in aqueous energy storage systems, metallic zinc suffers from dendrite formation that severely hinders its applications. Here we report texturing Zn as an effective way to address the issue of zinc dendrite. An in‐plane oriented Zn texture with preferentially exposed (002) basal plane is demonstrated via a sulfonate anion‐induced electrodeposition, noting no solid report on (002) textured Zn till now. Anion‐induced reconstruction of zinc coordination is revealed to be responsible for the texture formation. Benchmarking against its (101) textured‐counterpart by the conventional sulphate‐based electrolyte, the Zn (002) texture enables highly reversible stripping/plating at a high current density of 10 mA cm−2, showing its dendrite‐free characteristics. The Zn (002) texture‐based aqueous zinc battery exhibits excellent cycling stability. The developed anion texturing approach provides a pathway towards exploring zinc chemistry and prospering aqueous rechargeable batteries.National Research Foundation (NRF)Accepted versionThe authors appreciate the financial support by National Research Foundation of Singapore (NRF) investigatorship award number NRF-NRFI2017-08 (NRF2016NRF-NRFI001-22). The authors would like to acknowledge the Facility for Analysis, Characterization, Testing and Simulation, Nanyang Technological University, Singapore, for use of their electron microscopy/X-ray facilities

Hybrid electrolyte design for high-performance zinc–sulfur battery

Rechargeable aqueous Zn/S batteries exhibit high capacity and energy density. However, the long-term battery performance is bottlenecked by the sulfur side reactions and serious Zn anode dendritic growth in the aqueous electrolyte medium. This work addresses the problem of sulfur side reactions and zinc dendrite growth simultaneously by developing a unique hybrid aqueous electrolyte using ethylene glycol as a co-solvent. The designed hybrid electrolyte enables the fabricated Zn/S battery to deliver an unprecedented capacity of 1435 mAh g-1 and an excellent energy density of 730 Wh kg-1 at 0.1 Ag-1 . In addition, the battery exhibits capacity retention of 70% after 250 cycles even at 3 Ag-1 . Moreover, the cathode charge-discharge mechanism studies demonstrate a multi-step conversion reaction. During discharge, the elemental sulfur is sequentially reduced by Zn to S2- ( S8→Sx2-→S22-+S2-)${{\rm{S}}_8}{\bm{ \to }}{\rm{S}}_{\rm{x}}^{2{\bm{ - }}}{\bm{ \to }}{\rm{S}}_2^{2{\bm{ - }}}{\bm{ + }}{{\rm{S}}^{2{\bm{ - }}}})$ , forming ZnS. On charging, the ZnS and short-chain polysulfides will oxidize back to elemental sulfur. This electrolyte design strategy and unique multi-step electrochemistry of the Zn/S system provide a new pathway in tackling both key issues of Zn dendritic growth and sulfur side reactions, and also in designing better Zn/S batteries in the future.Agency for Science, Technology and Research (A*STAR)National Research Foundation (NRF)The authors acknowledge the grant from the National Research Foundation of Singapore (NRF) Investigatorship Award NRFI2017-08/NRF2016NRF-NRFI001-22 and A*STAR under the Advanced Manufacturing and Engineering (AME) programmatic fund number A20H3g2140

Bone Marrow-Derived Mesenchymal Stem Cells Maintain the Resting Phenotype of Microglia and Inhibit Microglial Activation

<div><p>Many studies have shown that microglia in the activated state may be neurotoxic. It has been proven that uncontrolled or over-activated microglia play an important role in many neurodegenerative disorders. Bone marrow-derived mesenchymal stem cells (BMSCs) have been shown in many animal models to have a therapeutic effect on neural damage. Such a therapeutic effect is attributed to the fact that BMSCs have the ability to differentiate into neurons and to produce trophic factors, but there is little information available in the literature concerning whether BMSCs play a therapeutic role by affecting microglial activity. In this study, we triggered an inflammatory response situation <i>in vitro</i> by stimulating microglia with the bacterial endotoxin lipopolysaccharide (LPS), and then culturing these microglia with BMSC-conditioned medium (BMSC-CM). We found that BMSC-CM significantly inhibited proliferation and secretion of pro-inflammatory factors by activated microglia. Furthermore, we found that the phagocytic capacity of microglia was also inhibited by BMSC-CM. Finally, we investigated whether the induction of apoptosis and the production of nitric oxide (NO) were involved in the inhibition of microglial activation. We found that BMSC-CM significantly induced apoptosis of microglia, while no apoptosis was apparent in the LPS-stimulated microglia. Our study also provides evidence that NO participates in the inhibitory effect of BMSCs. Our experimental results provide evidence that BMSCs have the ability to maintain the resting phenotype of microglia or to control microglial activation through their production of several factors, indicating that BMSCs could be a promising therapeutic tool for treatment of diseases associated with microglial activation.</p></div

BMSC-induced apoptosis of microglial cells.

<p>We investigated the effects of conditioned medium on apoptosis of microglial cells by TUNEL assay. (A) Cells were observed under a fluorescence microscope (magnification 400×), or stained with DAB and observed under an optical microscope (magnification 400×). We found fewer apoptotic cells in the LPS-treated groups compared with the control groups, while apoptosis was increased in the groups cultured in BMSC-CM. (B) The percentage of apoptotic microglial cells among the total number of microglial cells in each group is shown. Bars represent means plus or minus SD obtained from eight random fields. *P<0.05, **P<0.01, compared with control groups.</p