新一代计算机电源开关变换器的建模分析

介绍新一代计算机电源同步整流BUCK变换器工作在连续状态的建模分析,给出一种新的开关变换器的建模分析方法。该方法考虑了变换器在寄生元件,功率开关等效为理想开关与开通电阻的串联,理想开关由受控电流源和受控电压源替代,基于能量守恒原理确定开通电阻等效平均值,为了简化模型,建立了将平均寄生元件转移到电感之路中的映射规则,推导了同步整流BUCK变换器工作在连续状态的大信号平均模型、线性电路模型、DC和小信号电路模型,导出了开环传递函数,并进行了计算机仿真分析,结果令人满意。该建模分析方法的优点是考虑了变换器的寄生元件,其运算量比状态空间平均法小得多,模型直观、物理意义明确,便于进一步分析研究。     

二阶泛函微分方程解的渐近性与振动性

研究二阶泛函微分方程χ＂（ι）－Ρ（ι）ｆ（χ（τ（ι）））ｇ（χ‘（σ（ι）））＝０解的渐近性与振动性．给出了有界解振动的充分条件．     

基于可信性理论的电气化铁路牵引供电系统RAMS的模糊评估

应用故障树分析法建立了牵引变电所和接触网的可靠性模型,进而建立了整个牵引供电系统的可靠性模型.在大量调研的基础上,用梯形模糊变量来描述接触线、承力索和绝缘子的故障率及修复率,用三角形模糊变量来描述牵引变电所和接触网其他部件的故障率和修复率,将牵引供电系统的故障率、修复率和可用度等RAMS指标均视为随机模糊函数,利用可信度理论,实现了牵引供电系统的RAMS模糊评估.计算结果表明,牵引供电系统的可靠性主要取决于接触网的可靠性,而且只要知道了各部件故障率和修复率的大致分布,就可较准确地计算出牵引供电系统的RAMS指标,最大误差只有7%左右,满足工程精度的要求.     

面向任务的复杂系统韧性评估方法

随着战争形态加速向体系化、网络化、智能化转变,对军事系统韧性能力提出了更高的要求.在分析系统任务与韧性评估关系的基础上,提出一种面向任务的系统韧性评估方法.该方法首先给出一种面向任务的韧性评估框架.其次,在绝对时间尺度下考虑系统性能在任务过程中所受影响,并通过引入时间韧性指标,从时间韧性和性能韧性两个维度对系统的综合韧...     

3G业务运营支撑系统

文章介绍了业务运营支撑系统的现状,描述了3G业务运营支撑系统的功能和3G业务运营支撑系统的建设原则,并提出3G业务运营支撑系统的规划方案.     

Review of the fabrication and application of porous materials from silicon-rich industrial solid waste

Porous materials have promise as sound insulation, heat barrier, vibration attenuation, and catalysts. Most industrial solid wastes, such as tailings, coal gangue, and fly ash are rich in silicon. Additionally, a high silicon content waste is a potential raw material for the syn- thesis of silicon-based, multi-porous materials such as zeolites, mesoporous silica, glass-ceramics, and geopolymer foams. Representative sil- icon-rich industrial solid wastes (SRISWs) are the focus of this mini review of the processing and application of porous silicon materials with respect to the physical and chemical properties of the SRISW. The transformation methods of preparing porous materials from SRISWs are summarized, and their research status in micro-, meso-, and macro-scale porous materials are described. Possible problems in the application of SRISWs and in the preparation of functional porous materials are analyzed, and their development prospects are discussed. This review should provide a typical reference for the recycling and use of industrial solid wastes to develop sustainable “green materials.”