Comparative study of LiNiO2,LiNi0.8Co0.2O2and LiNi0.75Al0.25O2 for lithium—ion batteries

The comparative study of LiNi0.8Co0.2O2 and LiNi0.75Al0.25O2 was carried out by X-ray diffraction(XRD) and electrochemical methods.The results show that Co and Al doping suppress the phase transition during charge-discharge.The experiments indicate that LiNi0.75Al0.25O2 has the better cycle-ability and over-charge resistance comparing with LiNi0.8Co0.2O2,The interfacial behavior was studied by use of electrochemical impedance spectroscopy(EIS).The results show that LiNi0.75Al0.25O2 has a slightly larger polarization character than LiNi0.8Co0.2O2.     

Low Temperature Direct of Graphene onto Metal Nano‐Spindt Tip with Applications in Electron Emission

Graphene has been known for its superior electronic properties ever since its discovery in 2004. The high aspect ratio and ballistic transport properties exhibited by this one‐dimensional material are especially useful for electron emission applications. However, they are typically grown horizontally and excess efforts, such as the use of transfer techniques, is required to orientate them before effective electron emission from the graphene edges can occur. These transfer techniques have been shown to lead to additional defects to the as‐grown graphene structure, thereby degrading its properties. Here, we present an approach to directly fabricate graphene onto metal nano‐sized spindt tips (or nanocones) using the solid‐state transformation of carbon deposited from a pulsed laser system at low temperature. Besides providing a layer of chemical and mechanical protection for the metal nanocones, the graphene‐on‐metal nanocones gave enhanced emission properties compared to bare metal nanocones. This was due to the reduction of effective field emission tunneling barrier, which was a result of graphene‐metal charge transfer interactions. Controlling the metal nanocones density was also an important factor in determining the field emission performance, as electron screening from neighboring cones should be minimized.     

An improved thermal control of open cathode proton exchange membrane fuel cell

Proton exchange membrane fuel cell is a well-known technology that has shown high efficiency and performance as a power system compared to conventional sources such as internal combustion engines. Especially, open cathode proton exchange membrane is growing more popular thanks to its simple structure, low cost and low parasitic losses. However, the open cathode fuel cell performance is highly related to the operating temperature variation and the airflow rate which is adjusted through the fan voltage. In this regard, the present study investigates the thermal management of an open cathode proton exchange membrane fuel cell. The objectives are the stack performance improvement and the stack degradation prevention. Indeed, a safety and optimal operating zone governed by the load current, the stack temperature and the air stoichiometry, is designed. This optimal operating zone is defined based on the system thermal balance and the operating constraints. Hence, the proposed control strategy deals concurrently with the stack temperature regulation and the air stoichiometry adjustment to guarantee the goals achievement. The performance of the proposed control strategy is verified through experimental studies with different operating conditions and results prove its efficiency. To properly design an appropriate control strategy, a multiphysic fuel cell model is developed based on acausal approach by mean of Matlab/Simscape and experimentally validated.     

Mg-Ni合金的电沉积研究

采用电沉积的方法从非水体系和水体系中制备出镁-镍合金, 并且制备了氢氧化镍。X射线衍射、扫描电镜和能谱分析结果表明, 两种体系的沉积层均含有黑色非晶态的镁-镍合金, 呈结瘤状的微观形貌。初步研究了沉积机理以及镁-镍合金的电化学性能, 结果表明, 镁镍合金在两种体系中沉积析出电位均为-2.0 V(vs SCE), 沉积过程不可逆, 非水体系的沉积较水体系困难。水体系脉冲条件下沉积的镁-镍合金氧化还原可逆性良好, 其氢扩散系数很大, 与氢氧化镍组成电池的工作电压较大, 是一类良好的镍氢电池负极材料。     

真空微电子的发展

本文回顾了近十年来，真空微电子在材料（硅、金属、砷化镓和金刚石膜）、制备工艺、阴极结构及应用等方面的进展。并详细介绍一些新阴极结构的制备方法与特点，供选择参考。     

炮管膛线电解加工计算机仿真系统研究

炮管膛线电解加工需要通过试验反复修正阴极，研制周期长，试验难度大．采用OpenGL三维图形标准在Visual C＋＋编程环境下，开发计算机仿真系统，绘制阴极工作齿三维图形，利用专家系统提供的加工参数，实现对阴极运动轨迹及加工过程的仿真，最后对虚拟加工膛线进行线形检验，输出参数，完成阴极的虚拟设计、该系统操作简单，性能稳定，结果表明，这是减少实验工作量，缩短阴极设计周期的可行途径．     

国外隐身涂料及其发展

文章略述了国外隐身涂料的分类,设计原理,现状及其研究动向。     

合金阴极箔化学反应速度常数的测定

着重论述了合金阴极箔化学反应速度常数的测定方法及影响这一参数的两个重要因素（ＡｌＣｌ_３含量及温度）。还考查了这一常数在工艺生产管理控制中的应用，即对主腐蚀体系的稳定和容量水平的控制。     

真空电弧焊接与钎焊技术

主要研究真空条件下的自持放电电弧作为新型热源用于熔化焊及钎焊的工艺适应性。研究结果表明，该热源用于熔焊时，电弧挺度大，穿透能力强，焊缝正反面成形好，接头强度及塑性指标均优于常规焊接方法。而将其作为局部加热热源用于真空钎焊时，又具有电弧柔性大、升温速度快、参数可控性好、焊适民形好等优点。     

空心阴极烧结粉末冶金制品工艺研究

为了克服常现粉末冶金制品烧结工艺的缺点，试验研究了空心阴极等离子烧结工艺。介绍了空心阴极烧结装置、烧结方法、空心阴极功率输出特性和应用实例。