微波技术在RoHS指令检测中的应用简介

本文主要讲述了微波技术在RoHS指令相关检测中的一些应用。以及微波消解和微波萃取进行样品前处理方法。     

随机接入技术ALOHA协议在胎压报警系统中的应用

在越来越受重视的汽车电子中,胎压报警系统是一个很重要的环节.其中,将4个轮胎的气压监控模块放置在轮胎内部,分别作为4个发射从机,而中央接收器模块作为主机.这样,在数据的无线收发过程中,当有两个以上的轮胎气压同时发生异常需要报警时,就存在冲突发送的问题,即多点接入技术.本文首先分析了各种随机接入技术及其解决方案的比较;接着确定了在该系统中使用随机接入技术--ALOHA协议;分析了协议在系统中的具体应用.最后经过试验证明该协议是可行的.     

巨大变量组合逻辑设计优化软件的研究与设计

采用不同优化算法和机器处理方法来缓解机器资源对巨大变量组合逻辑综合问题的限制。介绍了软件系统设计的技术途径。以此形成的巨大变量逻辑优化软件，其输入、输出变量之和达到300。该软件通过了组合逻辑电路的benchmark例题测试。其优化效果的平均输入输出之比为0．652。     

基于MPEG4的自适应实时流媒体传输

论文阐述了在互联网环境下进行实时流媒体传输中存在的一些难点,并且给出了一个基于MPEG4的实时流媒体传输系统。并且希望能充分利用网络带宽,并且尽力减少媒体流由于网络时延和丢包所产生的影响。同时也关注由于丢包而引起的回放质量的下降问题。     

联机增量关联规则算法研究

在数据挖掘应用越来越普及的今天,传统数据挖掘系统的高代价和低效已经成为其更深应用的瓶颈,联机数据挖掘系统由于其自身的集成性正引领着数据挖掘研究新的方向。但联机增量数据挖掘系统中算法也需要作相应的改进才能够适应新的需求。文章是一篇关于在联机数据挖掘系统中进行关联规则分析的文献,实现了对联机数据挖掘系统中的并行和增量关联规则分析,并根据分析过程给出了实验结论。     

一种基于数字分析的相位差测量方法

相位差的测量是电量测量的一项基本内容，有着广泛的应用。提出了一种基于数字分析的相位差测量方法，其基本思想为采用中断技术扫描被测信号的波形，然后对扫描结果进行数字分析以求得相位差。该方法有效地避免了矩形波边沿抖动问题，能够比较容易地排除干扰信号，并能够对因被测信号中含有直流分量或运算放大器零点漂移等原因引起的矩形波边沿位置偏移问题进行修正。实际应用表明，该方法的测量结果准确、稳定、可靠。     

牵引变电所继电保护测试系统设计

根据牵引变电所继电保护系统的实际情况和测试要求，提出了一种利用工控机和PLC相结合的新设计方案，实现了继电器单体和整组的自动测试功能。详细地介绍了测试系统的软硬件设计，智能逻辑转换单元的构成，以及测试功能的实现过程。     

Shear localization-martensitic transformation interactions in Fe-Cr-Ni monocrystal

A Fe-15 wt pct Cr-15 wt pct Ni alloy monocrystal was deformed dynamically (strain rate ∼10⁴ s⁻¹) by the collapse of an explosively driven thick-walled cylinder under prescribed initial temperature and strain conditions. The experiments were carried out under the following conditions: (a) alloy in austenitic state, temperature above transformation temperature; (b) alloy in transformed state; and (c) alloy at temperature slightly above M _s , propitiating concurrent shear-band propagation and martensitic transformation. The alloy exhibited profuse shear-band formation, which was a sensitive function of the deformation condition. Stress-assisted and strain-induced martensitic transformation competes with shear localization. The alloy deformed at a temperature slightly above M _s shows a significantly reduced number of shear bands. The anisotropy of plastic deformation determines the evolution of strains and distribution of shear bands. The different conditions showed significant differences that are interpreted in terms of the microstructural anisotropy. Calculated shear-band spacings based on the Grady-Kipp (GK) and Wright-Ockendon (WO) theories are compared with the observed values. The microstructure within the shear bands was characterized by transmission electron microscopy. Regions of sub-micron grain sizes exhibiting evidence of recrystallization were observed, as well as amorphous regions possibly resulting from melting and rapid resolidification. This article is based on a presentation given in the symposium “Dynamic Deformation: Constitutive Modeling, Grain Size, and Other Effects: In Honor of Prof. Ronald W. Armstrong,” March 2–6, 2003, at the 2003 TMS/ASM Annual Meeting, San Diego, California, under the auspices of the TMS/ASM Joint Mechanical Behavior of Materials Committee.     

The solidification characteristics of Fe-rich intermetallics in Al-11.5Si-0.4Mg cast alloys

After the nucleation and sedimentation of primary Fe-rich phases, the microstructures of Al-11.5Si-0.4Mg cast alloys with 0.35–1.03Fe and 0.18–0.59Mn have been studied to investigate the solidification characteristics of Fe-rich phases. Depending on the iron and manganese contents as well as cooling rates, Fe-rich phases may solidify as predendritic (primary), pre-eutectic, coeutectic, and posteutectic intermetallics at the different stages of solidification through three types of reactions: (1) predendritic (primary), (2) eutectic, and (3) peritectic reactions. It seems that Fe-rich phases may nucleate on the wetted sides of double oxide films, while the gap of the dry sides of oxide films constitutes the cracks commonly observed in the Fe-rich phases and aluminum matrix. Conventional metallurgical observations also suggest that the Fe-rich phases nucleated early during the solidification might act as nuclei for those formed subsequently, although it has not been ruled out that these phases may share the same oxide substrates. It is probable that these nucleation events may all work as suggested in the possible nucleation hierarchy for Al-11.5Si-0.4Mg cast alloys.     

对华钢材料和备件采购管理系统现状分析及可整合方面的探讨

对华钢采购系统的业务重组进行了初步的分析，对华钢材料和备件采购系统的现状及可整合方面进行了初步探讨。同时借鉴国外大公司的成功经验，提出了对材料和备件采购系统整合方面的建议。内容包括：现状分析、优缺点比较和相关建议，意欲为相关的组织者和管理者提供一些参考，使整合后的采购管理系统更趋合理。