Comparison of gas sensing properties based on hollow and porous α-Fe<Subscript>2</Subscript>O<Subscript>3</Subscript> nanotubes

Hollow and porous α-Fe₂O₃ nanotubes were successfully synthesized by single nozzle electrospinning method followed by annealing treatment. The crystal structures and morphologies of the as-prepared materials were characterized by X-ray diffraction and scanning electron microscopy, respectively. The as-prepared materials were applied to construct gas sensor devices which gas sensing properties were further investigated. The obtained results revealed that porous α-Fe₂O₃ nanotube gas sensors exhibit a markedly enhanced gas sensing performance compared with hollow α-Fe₂O₃ nanotube gas sensors, which was about three times higher to 100 ppm acetone at 240 °C. Interestingly, hollow and porous α-Fe₂O₃ nanotube gas sensors both showed fast response–recovery time and good selectivity, but the porous ones possessed the shorter recovery time. The improved properties could be attributed to the unique morphology of porous nanotubes. Thus, further improvement of performance in metal-oxide-semiconductors materials could be realized by preparation the unique porous structures of nanotubes. Moreover, it is expected that porous metal-oxide-semiconductors nanotubes could be further design as promising candidates for gas sensing materials.     

WindowsCE.NET中断延迟测试与分析

嵌入式系统对实时性能一般要求较高,中断延迟是评估嵌入式操作系统实时性能的重要指标。利用ILTiming测试工具对WinCE4.2和5.0进行中断延迟测量,分析了导致中断延迟的原因,同时针对PXA255处理器的BSP提出了测试WindowsCE系统中断延迟的方法。     

水和甲醇存在下MAMS的消失反应动力学研究

通过实验研究了甲基丙烯酰胺硫酸盐（ＭＡＭＳ）与甲醇、水进行反应的动力学，并对该反应的机理进行了探讨。     

农村公共支出、基本建设投入与城乡收入差距

根据我国1978-2006年有关数据,建立向量自回归模型,对我国农村公共支出、基本建设投入与城乡收入差距的长期均衡关系进行了检验,在协整关系存在的前提下,进一步检验了三者的格兰杰因果关系,并利用脉冲响应函数对三者的动态关系进行了分析.实证结果显示,我国农村公共支出和基本建设投入有助于减少城乡收入差距,而且农业基本建设投入的作用较大.     

一种基于OPC技术的风电主控系统数据记录软件的开发与实现

OPC把对象链接和嵌入技术应用于工业过程控制领域,为工业控制领域提供了一种标准的数据访问机制.本文研究了OPCDA服务器和客户程序,并将OPC技术应用于风电领域常用的巴赫曼PLC控制器,利用VISUALBASIC开发了“主控系统数据记录软件”,并详细描述了该软件的使用方法,实践证明该软件在风场调试和工厂测试中得到了较好的效果.     

大型水电站地下厂房机组支撑结构动力特性研究

就在建的某大型水电站地下厂房结构 ,分析计算了 18种振源的频率 ,全部采用三维实体单元对其进行模拟 ,建立了多个三维有限元模型并进行了计算分析和共振校核 ,研究了机组支撑结构不同的结构布置形式 ,不同的边界条件和不同的材料对其动力特性的影响 ,得出了一些结论 ,为有效优化地下厂房结构的整体动力特性 ,改进抗振设计提供了途径和依据     

Study on Compound Effect of Bonded Magnets

The compound effect of Nd2Fe14B/Fe3B-Ferrite bonded magnets was studied.The result shows that the value ofβjHC obviously decreases with the ferrite content increasing.In addition, a functional relation between magnetic properties and ferrite content was clearly revealed by the physical relation in the magnetic powders.     

空气污染排放视角下中国核电的健康效益

核电在改善空气质量方面具有重要的作用。本文对比了核电与煤电的空气污染物排放系数,根据空气污染物引起的死亡率与人均燃煤发电量的负指数幂关系,评估了中国通过发展核电在改善空气质量方面对居民的健康效益,并对未来的健康效益进行了分析。结果显示,发展核电能够避免的死亡人数在增加。据估算,1995—2018年,中国核电累计可避免约4.7万人因空气污染物死亡,可避免约22.6万人因空气污染物患病。2020—2030年,预计会避免8.3万~9.4万人死亡,避免39.7万~45.1万人患病。