电流准谐振变换器的性能分析

本文对电流准谐振变换器电路的工作原理进行了分析,给出了准谐振电路在电网、负载变化时变换频率和功率开关导通时间变化的规律,分析了这种变换器的功率输出与变换频率、闭环方式的关系。     

IP电话的服务质量

随着IP网的快速发展,用IP来承载语音业务成为研究的热点。而服务质量是IP电话发展的障碍。本文在介绍了IP电话服务质量问题、要求及指标的基础上,重点对保障服务质量的资源预留及差分服务进行讨论。     

基于ARM的热泵热水系统测控模块硬件设计

介绍了具备除湿功能的热泵热水系统的工作原理,结合热泵热水系统的功能要求以及ARM芯片S3C2410的特点,采用了结构化、模块化的设计思想,实现了热泵热水系统测控模块的硬件设计,包括测控模块总体结构,S3C2410微控制器、人机接口、信号输入模块、信号输出模块、和通信模块等,实现了控制要求。     

卵形弹垂直侵彻混凝土介质的量纲分析

针对卵形弹侵彻半无限厚混凝土介质,采用量纲分析的方法建立了相关参数的无量纲化的函数关系,通过质量为2.85kg,弹径为50.8mm的卵形弹垂直侵彻混凝土实验确定撞击混凝土侵深的工程表达式.     

具奇异的非Newton渗流方程整体解存在性和渐进性

研究了一类奇异的非Newton多方渗流方程整体解存在性和渐进性，通过引进低能量函数的概念，证明了当初值uo(x)具有低能量时，其相应的解是整体存在的，且当t→∝时具有指数增长。     

国有企业非资源配置低效率的人力资本产权因素分析

国有企业非资源配置低效率的根本原因是由产权性质导致的国有企业治理结构的内在缺陷.本文从人力资本产权角度分析了国有企业委托结构链和刚性契约对非资源配置效率的影响,提出国有企业应建立人力资本产权与非人力资本产权共同参与企业经营控制和收益绩效分享的激励约束机制.     

Interfacial spin Hall current in a Josephson junction with Rashba spin—orbit coupling

We theoretically investigate the spin transport properties of the Cooper pairs in a conventional Josephson junction with Rashba spin-orbit coupling considered in one of the superconducting leads.It is found that an angle-resolved spin supercurrent flows through the junction and a nonzero interfacial spin Hall current driven by the superconducting phase difference also appears at the interface.The physical origin of this is that the Rashba spin-orbit coupling can induce a triplet order parameter in the s-wave superconductor.The interfacial spin Hall current dependences on the system parameters are also discussed.     

Spin-polarized transport in a normal/ferromagnetic/normal zigzag graphene nanoribbon junction

We investigate the spin-dependent electron transport in single and double normal/ferromagnetic/normal zigzag graphene nanoribbon (NG/FG/NG) junctions. The ferromagnetism in the FG region originates from the spontaneous magnetization of the zigzag graphene nanoribbon. It is shown that when the zigzag-chain number of the ribbon is even and only a single transverse mode is actived, the single NG/FG/NG junction can act as a spin polarizer and/or a spin analyzer because of the valley selection rule and the spin-exchange field in the FG, while the double NG/FG/NG/FG/NG junction exhibits a quantum switching effect, in which the on and the off states switch rapidly by varying the cross angle between two FG magnetizations. Our findings may shed light on the application of magnetized graphene nanoribbons to spintronics devices.