基于PLC的配料计量装置的设计

冶金生产中，各种原料之间的配比精度对生产过程的稳定和产品的质量有重要的影响。目前使用的配料系统计量精度低，瞬时物料流量波动大，系统复杂。本文介绍的计量装置的计量过程是对料斗内物料的减少量进行计量，以减重秤为主，配料精度达到0．5％级。     

纳米粒度测量方法浅析

本文介绍了多种纳米颗粒粒度的测量方法。主要讨论了X射线小角散射法、光子相关谱法和透射电镜-图像分析法的原理、适用范围及其优缺点。     

不同控制策略的小功率Boost-APFC性能研究

为了使用于小功率场合的功率因数校正电路的综合性能最优化,本文研究了采用电流断续模式或临界断续模式和电流连续模式的小功率Boost-APFC的各项性能。通过仿真分析和实验比较相结合的方法,定量给出了各电路在输入电流特性、效率、EMI滤波等性能上的具体差异,并且考虑了使用SiC二极管后对电路性能的影响。     

Flume Experiment on Stream Blockage by the Debris Flow From Tributary

Stream blockage by the debris flow from tributary valleys is a common phenomenon in mountainous area,which takes place when large quantities of sediment transported by debris flow reaches a river channel causing its complete or partial blockage.The dam formed by debris flow may causes upstream and downstream flooding,and presents great threat to people and property.Because of the catastrophic influence on people and property,debris-flow dam has attracted many attentions from the researchers and local administration.But,lit- tle attention has been given to the quantitative interrelationships of the potential influential factors.In this pa- per,the interrelationships of important influential factors caused the stream blockage by debris flow were ana- lyzed through flume experiment,and a model to predict the blockage was presented.     

铝箔轧机排烟系统防火设计改进措施

铝箔轧机发生火灾时常引燃轧机排烟系统。本文简要介绍了铝箔轧机排烟系统，对排烟系统着火的原因进行了分析，在此基础上提出了排烟系统防火、灭火的改进措施。     

表征PAN纤维和炭纤维微细结构的HRTEM样品制备方法

为用高分辨透射电子显微术(HRTEM)表征聚丙烯腈(PAN)纤维和炭纤维的微细结构，从纤维性能出发，探讨研碎、离子束减薄和超薄生物切片三种制备方法及其工艺步骤，结合实验结果，对比了三种制备方法的原理、优缺点，提出了制备方法的适用范围和选择原则，并推断适于表征预氧化纤维微细结构的样品制备方法。与生物样品的制备方法类似，把超薄生物切片法引入到纤维材料HRTEM样品制备领域，为系统研究炭纤维微细结构的演变提供了线索。     

DWT－Based Watermarking Scheme for Digital Images

A watermarking scheme for digital images is introduced. This method is based on discrete wavelet transform and spread spectrum technique. A discrete wavelet transformed binary signature image is expanded by an m-sequence and added to the large wavelet coefficients of a host image with a scale factor. Good balance be-tween transparency and robustness is achieved by the selection of the scale factor. In addition, the spread spec-trum technique is adopted to increase the robustness of this watermarking scheme. The experimental results show that the proposed method is of good performance and robustness for common image operations such as JPEG lossy compression, etc.     

MAX197A/D转换器多通道特性在激光电源监控系统中应用

利用了MAXl97的多通道采样特性，实现了高功率激光加工机电源部分的可靠采样，保证采样速度，克服单通道带来干扰，使电源的监控系统可靠工作。     

On the order of stable compensators for a class of time-delay system

The stabilization using a stable compensator does not introduce additional unstable zeros into the closed-loop transfer function beyond those of the original plant, so it is a desirable compensator, the price is that the compensator‘s order will go up. This note considered the order of stable compensators for a class of time-delay systems. First, it is shown that for single-loop plants with at most one real fight-half plane zero, a special upper bound for the minimal order of a strongly stabilizing compensator can be obtained in terms of the plant order; Second, it is shown that approximate unstable pole-zero cancellation does not occur,and the distances between distinct unstable zeroes are bounded below by a positive constant, then it is possible to find an upper bound for the minimal order of a strongly stabilizing compensator.     

Computers in police cruisers

A typical police cruiser is filled with electronic devices, displays, and inputs, all competing for the officer's attention. The Project54 system integrates those devices, and its speech-based user interface lets officers operate them without taking their eyes off the road.