Nanoindentation measurement of core–skin interphase viscoelastic properties in a sandwich glass composite

Mechanics of Time-Dependent Materials - Debonding at the core–skin interphase region is one of the primary failure modes in core sandwich composites under shear loads. As a result, the...     

Effect of Si/Fe ratio on the boron and phosphorus doping efficiency of β-FeSi2 by magnetron sputtering

Boron-doped or phosphorus-doped β-FeSi₂ thin films have been prepared on silicon substrate by magnetron sputtering. Effects of Si/Fe ratio on the boron and phosphorus doping efficiencies have been studied from the resistivities of doped β-FeSi₂ thin films and current-voltage characteristics of doped β-FeSi₂/Si heterojunctions. The experimental results reveal that the carrier concentration and doping efficiency of boron or phosphorus dopants at the Fe-rich side are higher than that at the Si-rich side. The effect of Si/Fe ratio can be deduced from the comparison of the formation energies under two extreme conditions. At the Fe-rich limit condition, the formation energy of boron or phosphorous doping is lower than that at the Si-rich condition. Therefore, the activation of impurities is more effective at the Fe-rich side. These results demonstrate that the boron-doped and phosphorous-doped β-FeSi₂ thin films should be kept at the Fe-rich side to avoid the unexpected doping sites and low doping efficiency.     

Studied on a novel human keratinocyte membrane delivery system in vitro

The culture of keratinocytes on flexible membranes has been proposed as a means to simplify, accelerate and improve the efficiency with which proliferating cells are delivered to full thickness or non-healing skin defects. The purpose of this article was to study the ability of chitosan-gelatin manbranes to facilitate the growth of human keratinocytes. The membranes with different chitosan contents were studied. The surface properties of chitosan-gelatin membranes were investigate by SEM, and water contact angle test. The mechanical property of the membranes was tested. Data implied that gelatin could make the membranes more flexible and hydrophilic than chitosan membranes, which may regulate the seeded cells behavior. Loading human keratinocytes on chitosan-gelatin membranes, cells attachment, spread, and growth were investigated by light microscopy, SEM, and MTT test. The results suggested that the adhesion and proliferation of keratinocytes seeded on chitosan-gelatin membranes were same as on tissue culture plate, in which gelatin could modify the interaction between keratinocytes and chitosan membranes. Therefore, chitosan-gelatin membrane is a good candidate for keratinocytes delivery system.     

Piezoelectric and dielectric properties of PZN-BT-PZT solid solutions

Pb(Zn_1/3Nb_2/3)O₃ ceramics with the perovskite structure can be stabilized by substituting 6–7 mol % BaTiO₃ (BT). Piezoelectric and dielectric properties of the pseudo-binary system (1–x)(0.94PZN-0.06BT) -xPb(Zr_(1–y)Ti_y)O₃ were studied, and the effects of Zr/Ti ratios and thermal annealing process on the piezoelectric and dielectric properties were also discussed. The results show that the piezoelectric properties of this ceramic system are very good when x is about 0.50 and y is about 0.47 with K_p = 70%, d₃₃=560 pC/N, _m #x2248;23,000. These ceramics are favorable to piezoelectric actuators.     

电站锅炉制造企业技术创新项目选择的关键因素研究

技术创新项目选择作为电站锅炉制造企业的重大决策,除了受项目自身技术水平的影响,还受到其他诸多因素的制约.本文从几个关键因素着手进行分析,希望为电站锅炉制造企业技术创新项目的正确选择提供参考.     

S波段微波照射对大鼠免疫功能的影响

用S波段高功率微波照射大鼠,观察大鼠白细胞计数、淋巴细胞数、T细胞及其亚群和免疫球蛋白的变化,以期了解S波段高功率微波照射对大鼠免疫功能的影响.结果表明,S波段高功率微波照射可以引起大鼠白细胞水平降低,T细胞亚群出现兴奋效应,免疫球蛋白早期出现不同程度的降低,表现出低剂量刺激而高剂量抑制的效应.     

Fixed-time sliding mode control based plant/controller co-design of dual-motor driving system

A fixed-time sliding mode controller based plant/controller co-design scheme is developed for dual-motor driving systems. The proposed controller is fixed-time stable subject to unknown disturbances which guarantees the robustness of the proposed control scheme and a less conservative solution can be ensured by comparing with the conventional fixed-time convergence technique. Due to the existence of couplings between the plant and the controller, traditional design procedures in which the plant and the controller are designed sequentially and separately cannot guarantee the overall optimum of control systems. A co-design scheme based on the nested optimisation strategy is developed in this paper. With the nested optimisation strategy, the co-design solution can be achieved efficiently and reliably. A combined cost function considering both the plant and the controller is developed so that the largest load can be achieved without degrading the control performance. The fixed-time convergent controller is employed and considered into the co-design scheme. The gravitational search algorithm is adopted to optimise controller parameters in the co-design scheme. With the presented co-design method, the largest load of the studied system can be achieved with the satisfactory control performance. Contrastive Simulation and experimental results demonstrate the efficacy of the proposed controller and co-design scheme.     

Milling process simulation for the variable pitch cutter based on an integrated process-machine model

Milling process simulations provide a useful way to design and adjust the technical parameters of milling process. As the milling process involves coupling     

Realizing simultaneously enhanced energy and power density fullcell construction using mixed hard carbon/Li_4Ti_5O_(12) electrode

Practical applications of lithium-ion batteries(LIBs) with both high energy and power density are urgently demanded,which require suitable charge/discharge platform,fast charge-transfer kinetics,as well as optimal solid electrolyte interphase(SEI) layer of electrode materials.In this work,a high-performance lithium-ion battery(LIB) full cell was assembled by using commercial LiNi_(0.33)Co_(0.33)Mn_(0.33)O_2(NCM111) as the positive electrode and mixed Li_4 Li_5 O_(12)(LTO)/hard carbon(HC) as the negative electrode.It reveals that the component ratio between LTO and HC plays a critical role in manipulating the electric conductivity and the electro-reaction platform.The electrochemical test results show that when the content of HC is 10 wt%,the as-constructed full cell demonstrates the best electrochemical,with a maximum energy density of 149.2 Wh·kg~(-1) and a maximum power density of2195 W·kg~(-1) at 10 A·g~(-1)(30 C).This outperforms all the assembled systems within our work range and the state-ofthe-art literatures.The NCM//Li_4 Ti_5 O_(12)+10 wt% HC battery system also exhibits a good capacity retention after1000 cycles at the current density of 1 A·g~(-1).This work provides a new approach to enhance the full-cell performance by mixing electrode materials with different charge potentials and reaction kinetics.     

变电运行动态培训仿真系统的研制

本文重要介绍用于电气运行人员培训的动态仿真专家系统的设计思想、实现方法及其应用效果。