混合动力电动汽车用电机及驱动控制器的电磁兼容设计

电机及驱动控制器作为电动汽车的关键部件,其电磁兼容设计对于保证电动汽车的可靠运行非常重要.介绍了国家十五项目中某混合动力轿车用电机及控制器系统的电磁兼容措施,分别从控制电路、信号电缆、功率电路及屏蔽机箱等工程角度进行了分析和设计.该系统的电磁兼容性符合GB/T17619-1998的要求,且已应用于实际混合动力电动汽车,运行情况良好.     

IGCT 综合型电荷控制 模型的建立和仿真

以电荷控制方程而建立的IGCT综合型电荷控制模型，经关键性的关断电流和关断电压进行了仿真分析，所得结果与实际结果吻合。因此该模型是有效的，可用于IGCT的开关特性分析和集成门极电路设计。     

宽工作电压范围单电源CMOS误差放大器

采用0.8μm标准数字CMOS工艺(VTN0=0.836V,VTP0=0.930V),设计并流片验证了具有宽工作电压范围(3～6V),可作SOC系统动态电源管理芯片内部误差放大器应用的单电源CMOS运算放大器。该误差放大器芯核同时具有适合低电压工作,并对工艺参数变化不敏感的优点。对于相同的负载情况,在3V的工作电压下,开环电压增益AD=83.1dB,单位增益带宽GB=2.4MHz,相位裕量Φ=85.2°,电源抑制比PSRR=154.0dB,转换速率Sr=2.2V/μs;在6V工作电压下,AD=85.1dB,GB=2.4MHz,Φ=85.4°,PSRR=145.3dB,Sr=3.4V/μs。     

智能天线对移动通信网性能的影响

智能天线是目前移动通信中的热点话题之一，也是提升网络容量和改善传输质量的关键技术。本文简要介绍了智能天线基本概念，原理及其在无线网络中的重大作用。     

高速贴片机优化软件的设计与开发

SMT生产线要达到最大的产量,必须要考虑生产线的效率。贴片机是SMT生产线中的关键设备,因此提高贴片机的生产效率具有十分重要的意义。本文以松下贴片机为例,介绍了贴片机程序优化软件的设计与开发中的思想、方法和经验,希望对从事CAM软件研究的工程人员有一定帮助。     

CPU芯片封装技术的发展演变

本文主要介绍了CPU芯片封装技术的发展演变,以及未来的芯片封装技术。同时,从中可以看出芯片技术与封装技术相互促进,协调发展密不可分的关系。     

用等厚干涉测定液体折射率

介绍一种采用等厚干涉原理测定液体折射率的简单可靠的方法。     

Study of asymmetric charge writing on Pb(Zr,Ti)O3 thin films by Kelvin probe force microscopy

Polycrystalline Pb(Zr_0.55Ti_0.45)O₃ thin film was deposited on Pt/Ti/SiO₂/Si(1 0 0) by radio-frequency-magnetron sputtering method, and the writing of charge bits on the surface of PZT thin film was studied by Kelvin probe force microscopy. It is found that the surface potential of the negative charge bits are higher than those of the corresponding positive ones. When ferroelectric polarization switching occurs, the potential difference becomes even more remarkable. A qualitative model was proposed to explain the origin of the asymmetric charge writing. It is demonstrated that the internal field in the interface layer, which is near the ferroelectric/electrode interface in ferroelectric film, is likely to be the cause for the occurrence of this phenomenon.     

Nanostructured thermoset epoxy resin templated by an amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) diblock copolymer

An amphiphilic poly(ethylene oxide)‐block‐poly(dimethylsiloxane) (PEO–PDMS) diblock copolymer was used to template a bisphenol A type epoxy resin (ER); nanostructured thermoset blends of ER and PEO–PDMS were prepared with 4,4′‐methylenedianiline (MDA) as the curing agent. The phase behavior, crystallization, hydrogen‐bonding interactions, and nanoscale structures were investigated with differential scanning calorimetry, Fourier transform infrared spectroscopy, transmission electron microscopy, and small‐angle X‐ray scattering. The uncured ER was miscible with the poly(ethylene oxide) block of PEO–PDMS, and the uncured blends were not macroscopically phase‐separated. Macroscopic phase separation took place in the MDA‐cured ER/PEO–PDMS blends containing 60–80 wt % PEO–PDMS diblock copolymer. However, the composition‐dependent nanostructures were formed in the cured blends with 10–50 wt % PEO–PDMS, which did not show macroscopic phase separation. The poly(dimethylsiloxane) microdomains with sizes of 10–20 nm were dispersed in a continuous ER‐rich phase; the average distance between the neighboring microdomains was in the range of 20–50 nm. The miscibility between the cured ER and the poly(ethylene oxide) block of PEO–PDMS was ascribed to the favorable hydrogen‐bonding interaction. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3042–3052, 2006     

无保护间隔的OFDM信道自适应均衡的一种新算法

近年来作为一种特殊的多载波调制方式——正交频分复用(OFDM)已得到越来越多的人的关注.对于传统的OFDM系统来说,如果循环前缀的长度大于信道的时延扩散值,则可以通过简单的频域均衡来解调OFDM信号.可是循环前缀的使用却降低了系统的传输效率,如果能压缩甚至去掉循环前缀,而保持系统性能不变,则是很有意义的,为此本文给出了一种新的均衡结构,利用循环迭代手段以减少甚至去掉循环前缀,最后通过计算机模拟,证实了这种结构的有效性.