Development of a fast neutron radiography converter using wavelength-shifting fibers

A fluorescent converter for fast neutron radiography (FNR) comprising a scintillator and hydrogen-rich resin has been developed and applied to electronic imaging. The rate of the reaction between fast neutrons and the converter is increased by thickening the converter, but its opaqueness attenuates emitted light photons before they reach its surface. To improve the luminosity of a fluorescent converter for FNR, a novel type of converter was designed in which wavelength-shifting fibers were adopted to transport radiated light to the observation end face. The performance of the converter was compared with that of a polypropylene-based fluorescent converter in an experiment conducted at the fast-neutron-source reactor YAYOI in the University of Tokyo.     

基于片上DC-DC的CMOS光接收机前置放大器

利用CSMC 0.6μm CMOS工艺,设计了基于片上DC-DC转换器的光接收机前置放大器。电路采用可调跨阻放大器与片上DC-DC结构,有效地克服了单端跨阻放大器易受电源波动的干扰,并解决了高灵敏度与低失真相互矛盾的问题。模拟结果表明,输入动态范围为83 dB(峰-峰值=0.2μA~3 mA),等效输入电流噪声为1.2 pA/Hz(155 MHz),可稳定工作在155 Mb/s速率上;在5 V电源电压下,功耗为95 mW。     

光通信技术讲座--(五):WDM系统光节点器件

介绍WDM系统光节点所用到的器件,如波长转换器、光分插复用器及其使用的光隔离器和光环形器.     

无刷双馈电机极数的选择

将三种极对数的无刷双馈电机(BDFM)与一台绕线转子感应电机进行比较研究。用双向变频器对BDFM进行速度控制，做到减小额定值，并可以实现对BDFM的转速和功率因数进行控制。本文说明了选择变频器的额定值和BDFM的极对数的方法。     

氨合成塔出口氨含量偏低原因分析及对策

阐述UHDE合成塔运行现状 ,分析氨净值达不到设计值的原因 ,提出相应的解决措施     

转炉负能炼钢攻关对策

通过介绍转炉炼钢工艺流程及工序能耗分析，为提高转炉煤气回收量及降低电耗采取了一系列攻关措施，实现了转炉负能炼钢，取得了一定经济效益。     

有源滤波器的设计

首先阐明有源滤波器的基本概念和传递函数,然后着重介绍具有低灵敏度的GIC型双运放电路和在较高频率时应用的开关电容滤波器,最后举例说明它们的应用.     

A COMPUTER-AIDED UNIFIED APPROACH TO MODELING PWM AND RESONANT CONVERTERS

This letter puts forward a method of modeling for the steady-state and small signal dynamic analysis on PWM, quasi-resonant and series/（parallel） resonant switching converters based on pulse-waveform integral approach. As an example, PWM and quasi-resonant converters are used to discuss the principle of the approach. The results are compared with those in the relative literatures. Computer aided analysis are made to confirm the correctness.     

基于EWB的D/A数模转换器的仿真研究

阐述了D／A转换器的仿真原理，给出了T形电阻网络D／A转换器仿真模型的构造方法，并采用EWB进行了系统仿真，仿真结果表明该方法是合理、可行的。     

三元催化转化器中的现象分析与研究

在介绍和分析国内外研究现状的基础上，论述了三元催化转化器中的传递现象及化学反应动力学．探讨了三元催化转化器在暖机过程中有害物质的催化转化模型，并建议采用数学模型的方法对催化器在发动机所有工况下的工作过程进行模拟。