Hydrogen storage: The major technological barrier to the development of hydrogen fuel cell cars

In this paper, we review the current technology for the storage of hydrogen on board a fuel cell-propelled vehicle. Having outlined the technical specifications necessary to match the performance of hydrocarbon. fue1, we first outline the inherent difficulties with gas pressure and liquid hydrogen storage. We then outline the history of transition metal hydride storage, leading to the development of metal hydride batteries. A viable system, however, must involve lighter elements and be vacuum-tight. The first new system to get serious consideration is titanium-activated sodium alanate, followed by the lithium amide and borohydride systems that potentially overcome several of the disadvantages of alanates. Borohydrides can alternatively produce hydrogen by reaction with water in the presence of a catalyst but the product would have to be recycled via a chemical plant. Finally various possible ways of making magnesium hydride decompose and reform more readily are discussed. The alternative to lighter hydrides is the development of physisorption of molecular hydrogen on high surface area materials such as carbons, metal oxide frameworks, zeolites. Here the problem is that the surface binding energy is too low to work at anything above liquid nitrogen temperature. Recent investigations of the interaction mechanism are discussed which show that systems with stronger interactions will inevitably require a surface interaction that increases the molecular hydrogen-hydrogen distance.     

Influence of the evaporation rate and the evaporation mode on the hydrogen sorption kinetics of air-exposed magnesium films

It has been shown that the hydrogen sorption properties of air-exposed magnesium films are influenced by the deposition parameters such as the evaporation rate or the evaporation mode used during their preparation. As the evaporation rate increases, the structure of the film tends to be highly oriented along the [002] direction and the kinetics of hydrogen absorption and desorption are faster. Moreover, the hydrogen sorption kinetics of magnesium films prepared with an electron beam source under a high vacuum are faster by almost a factor of two compared to those prepared using resistive heating under low vacuum. These two parameters reduce drastically the activation and the incubation period during hydrogen absorption and desorption, respectively.     

Simultaneous recrystallization, phosphorous diffusion and antireflection coating of silicon films using laser treatment

Laser technique application to polycrystalline silicon thin-film solar cell fabrication on glass substrates has received appreciable attention. In this paper, a laser-doping technique is developed for plasma-deposited amorphous silicon film. A process involving recrystallization, phosphorous diffusion and antireflection coating can be achieved simultaneously using the laser annealing process. The doping precursor, a phosphorous-doped titanium dioxide (TiO₂) solution, is synthesized using a sol-gel method and spin-coated onto the sample. After laser irradiation, the polycrystalline silicon grain size was about 0.5∼1.0 μm with a carrier concentration of 2 × 10¹⁹ cm^− 3 and electron mobility of 92.6 cm²/V s. The average polycrystalline silicon reflectance can be reduced to a value of 4.65% at wavelengths between 400 and 700 nm, indicating the upper TiO₂ film of antireflection coating.     

一种新型非接触圆盘压电微电机

提出了一种新型圆盘压电微电机，定子与转子间是非接触型的。定子工作在砘振动模态，并激励定子产生圆周方向单向行波。该电动机具有结构简单、易于制作、转速高等特点，电动机测试最高转速达到2225r／min。     

基于Oracle学评教系统解决方案

基于Oracle开发的学生网上评教系统具有比传统数据库如SQL Server和Access更好的系统性能、事务控制能力、稳定性、安全性和权限控制,同时使用Oracle各种特性能有效地减少开发人员的编程难度,提高了整个学生评教系统的可维护性.以重庆邮电大学移通学院开发的学生网上评教系统为例,阐述了Oracle 9i数据库在高校评教系统中的应用.     

土壤中产碱性脂肪酶霉菌的筛选

利用RhodamineB平板筛选模型，以PVA橄榄油为底物的NaOH滴定法为测酶活主要方法，从沈阳化工学院附近含油脂丰富的土壤中筛选得到产碱性脂肪酶能力较高的霉菌M20．对其产酶条件进行优化，最终得到培养基中最佳碳源为葡萄糖2％＋植物油3％，最佳氮源为4％酵母膏，最适初始pH为8．0，最适产酶时间36h，将酶液于4℃下保存，酶活力可在3d内保持稳定．     

PT二次误接线导致的定子接地保护拒动分析

国内某电厂的定子接地保护拒动起因于不正确的PT接线。文章分析了当PT二次侧采用B相接地时,PT与电压变换器的中性点连接方式对保护动作行为的影响。结论表明:当二者中性点断开时,保护装置的测量结果不能正确反映一次系统的运行状态,PT断线判据可能误动;而当中性点直接相连时,保护装置能够正确动作。     

基于三层B/S结构的梯级水电厂中长期优化调度

介绍了一种运用Internet技术和数据库技术，采用数据库、服务器、浏览器三层结构的梯级水电厂中长期优化调度系统，论述了该系统设计与开发的目标、配置环境、系统结构和功能、关键技术和标准化设计。采用Web Service技术和ASP．NET开发工具，开发出了先进、实用、可靠和界面友好的应用软件，并在多个梯级水电厂运行，效果良好。     

基于C/S+B/S双模式的分布式远程诊断专家系统

分布式远程诊断专家系统（DRFDES）是故障诊断领域的发展趋势之一。为此文章深入研究了其工作原理、实现的硬软件结构及工作过程，分析了Web数据库的体系的两层C／S结构和三层B／S结构厦其在DRFDES中的优缺点，在该基础上提出了一种基于C／S和B／S混合模式的数据库体系的分布式远程故障诊断专家系统，探讨了故障诊断知识库的更新模式，并对分布式远程诊断专家系统实现的理论基础和关键技术进行了研究。     

嵌入式系统Bootloader的设计与实现

利用Jediview集成开发环境和JEDI仿真器,完成了基于S3C44B0X嵌入式芯片的实验开发板EV44B0II的Bootloader的设计与实现.