电动汽车复合电源在环测试平台研究概况

电源是电动汽车动力系统的核心部件,复合电源技术已成为现代新能源电动汽车发展的关键技术之一.介绍了电动汽车及车载电源的发展,阐述了复合电源性能测试研究方法,分析比较了国内外复合电源性能测试平台的研究现状,提出了复合电源性能在环测试平台存在的问题.     

串补装置中快速暂态过程的建模与时域求解

为了对间隙放电在串补平台设备上造成的快速暂态过电压进行评估,以部分单元等效电路(partial element equivalent circuit,PEEC)为基础,提出了含有集中元件支路的考虑全部段间电磁耦合的复杂多导体系统建模方法.此外还对含有非线性元件的复杂多导体系统状态方程的时域求解方法进行了深入研究.典型算例下与EMTP计算结果的对比表明,该文采用的方法计算结果准确,此外与传统方法相比对于紧密耦合的复杂多导体系统(如串补装置)电磁暂态过程的仿真具有更好的适用性.     

基于复合材料理论的土壤——根系力学研究

从微观的角度研究了根系——土壤复合体的宏观力学性质,并通过计算机模拟试验,研究了土壤和根系——土壤复合体的应变。结果表明,生态防护对加固土壤、保护边坡体有可支持的力学依据,能够有效的提高土壤的力学性质。     

Research on theory and key technology of trusted computing platform security testing and evaluation

Trusted computing has become a new trend in the area of international information security, and the products of trusted computing platform begin to be used in application. Users will not use the products of information security, unless it goes through the testing and evaluation. Here we concentrate on the testing and evaluation problem of trusted computing platform, begin with constructing proper formalization model of trusted computing platform for testing, and establish a mathematical chain of trust model...     

Comments on “Wirtinger-based integral inequality: Application to time-delay systems [Automatica 49 (2013) 2860–2866]”

In a recent paper (Automatica 49 (2013) 2860–2866), the Wirtinger-based inequality has been introduced to derive tractable stability conditions for time-delay or sampled-data systems. We point out that there exist two errors in Theorem 8 for the stability analysis of sampled-data systems, and the correct theorem is presented.     

Investigation of Eu-doped mesoporous titania phosphor with enhanced luminescence

A novel mesoporous TiO2 phosphor doped with Eu was synthesized through a facile hydrothermal synthesis method using cetyltrimethylammonium bromide as structure template reagent. The samples were characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscope, high-resolution transmission electron microscopy, ultraviolet visible diffuse reflectance, X-ray photoelectron spectroscopy, and three dimensional Photoluminescence. The X-ray diffraction results demonstrated that the products were anatase type with polycrystalline. N2 adsorption-desorption analysis showed that the samples were of high ordered double mesoporous structures. Eu-doped mesoporous TiO2 indicated the typical fluorescent spectra of Eu3+ ion occurred: the excited-states at 5L6 (394 nm), 5D2 (465 nm) and 5D1 (535 nm); the main emission peaks at 592 and 617 nm, corresponding with the transitions 5D0 --> 7F1 and 5D0 --> 7F2, respectively. Meanwhile, the phenomena of Eu(3+)-doped mesoporous TiO2 phosphor with efficient nonradiative energy transfer from the mesoporous TiO2 host to the activator Eu3+ ions was observed and possible emission mechanism was proposed. High dispersion of Eu in mesoporous TiO2 matrix was responsible for enhanced luminescence.     

A novel ethanol gas sensor based on ZnO-microwire

One-dimensional (1D) ZnO microwires were successfully synthesized by chemical vapor deposition and their structural and morphological properties were analyzed by X-ray diffraction and scanning electron microscopy, demonstrating that the microwires were single crystalline with perfect hexagonal structure and smooth surface. Using these 1D microstructures, we fabricated a novel ZnO-based ethanol gas sensor. Operating at room temperature, the sensor was found to have good sensing characteristics. The reliability and stability of the sensor could be improved by connecting multiple 1-wire devices (1-WD) in parallel into a multi-wires device. In interior natural lighting environment and under 3 V bias, the response and recovery time of the 1-WD to 200 ppm ethanol gas were <10 s and about 300 s, respectively, and the minimum and maximum detection limit were about 2 and 200 ppm, respectively. A sensing model was proposed for discussing the performance of the sensor. The simplicity in fabrication, low power consumption and low cost make the sensor suitable for practical application in many fields, especially in identifying driving under the influence and chemical industry monitoring.     

电容器故障监测系统的应用研究

基于近年并联电容器装置频繁出现故障的现象和特点,研制出一套电容器故障监测系统,分别提取并联电容器装置的电流和电压实时信号,利用Labview虚拟仪器程序进行软件开发实现在线监测,对获取的电流电压信号进行谐波、合闸涌流、暂态过电压等方面进行分析和研究,并应用于现场测量,给出了一起电容器内部击穿故障的监测实例。     

高性能计算机电源系统的设计与实现

从系统级、机柜级、板级三方面详细介绍了某高性能计算机电源系统的实现方案。重点介绍了计算板的电源和控制电路的设计方法,并对电源系统的稳定性进行了分析,提出了解决方法,最后给出了系统运行时的电源实测波形。运行结果表明,该系统具有供电质量高,可靠性高,易于维护,能进行故障诊断等优点。     

上海历史文化风貌区的分类比较与保护规划的应对

2003年,上海市划定了中心城12个历史文化风貌区,它融合了上海城市发展过程中各个时代的鲜明风格,体现了近代上海在社会经济、文化、生活各方面的成就和发展轨迹.由于上海这样的大都市的历史风貌复杂、多样,每个风貌区所面临的问题也不尽相同,因此保护规划在统一的规划框架下,必须有不同的变化和侧重.分类比较的目的就是为了进一步归纳总结,完善保护规划体系,使风貌区保护规划编制方法更加易于推广.