A new efficient method for one‐pot conversions of aryl carboxylic acids into nitriles without solvent

A new efficient method for synthesising nitriles, important organic reagents, is reported in this paper. In an environmentally benign solvent‐free system, aryl carboxylic acids were converted into the corresponding nitriles via one‐pot reactions, by amidation with ethyl carbamate followed by dehydration with thionyl chloride, in excellent yields. The results showed that the method has the advantages of lower cost, higher yield, less pollution and greater ease of work‐up. Copyright © 2008 Society of Chemical Industry     

Modeling wireless fading channels via stochastic differential equations: identification and estimation based on noisy measurements

This paper is concerned with modeling and identification of wireless channels using noisy measurements. The models employed are governed by stochastic differential equations (SDEs) in state space form, while the identification method is based on the expectation-maximization (EM) algorithm and Kalman filtering. The algorithm is tested against real channel measurements. The results presented include state space models for the channels, estimates of inphase and quadrature components, and estimates of the corresponding Doppler power spectral densities (DPSDs), from sample noisy measurements. Based on the available measurements, it is concluded that state space models of order two are sufficient for wireless flat fading channel characterization.     

探讨某高级车库设计需要注意的几点问题

广州市现在每天增加的小汽车数量就在400辆以上，这种迅猛的增长势头除了对城市的交通运输网络造成很大的压力外，城市的停车缺口也在不断扩大，现在广州市的停车位缺口就在30万辆左右。针对这种情况，地方政府正在加大解决城市停车难问题的力度．其中一项措施就是增加建设停车库。     

壳聚糖醇水分离膜的研究

本文制备了一系列不同脱乙酰度壳聚糖，研究了不同脱乙酰度聚糖膜的醇水分离性能，结果表明，随着脱乙酰度的增大，分离因子升高，渗透通量减小。当脱乙酰度大于９０％时，有较高的分离因子，符合单级分离要求。同时考察了料液浓度，料液温度等条件对壳聚糖膜醇水分离性能的影响，求得水和乙醇透过壳聚糖的表观活化能分别为：△Ｅｗ＝３２．６ｋＪ／ｍｏｌ，△Ｅｅ＝５７．２ｋＪ／ｍｏｌ。     

淀积条件对GDa—SiNx薄膜电学特性的影响

本文讨论了用辉光放电法制备氮化硅薄膜时衬底温度、射频功率和气体流量比对薄膜的电导率、介电常数和击穿强度的影响。通过优化生长条件，制备了优质非晶氮化硅薄膜，其介电常数为７．５、击穿强度为５．５ＭＶ／ｃｍ、电导率为１０－１３（Ωｃｍ）－１。     

油田放射性作业人员外周血淋巴细胞染色体畸变的观察

本文调查了油田212例受γ射线和中子混合辐射照射的作业人员和30例正常人的外周血淋巴细胞染色体畸变。作业人员受γ射线照射的人均年受照剂量为1.28mGy。调查结果表明,放射性测井人员与正常人相比染色体畸变率有显著差异。     

收尽铁路油槽车底油的措施

介绍了造成铁路油槽车底油收不尽的原因，一是节约意识差；二是设备设施陈旧或维护不够；三是操作不当。提出了增强节约意识，挖掘设备潜力，采用合理的吸油方法的对策。     

基于Linux VMware虚拟机的串口通信

嵌入式开发领域经常使用串口通信,但串口通信方式占用很多硬件资源,设备的利用率较低。文章研究了基于Linux VMware虚拟机进行串口通信的Use Physical Serial Port模式、Use Out File模式以及Use Named Pipe模式的功能和特点,给出了基于VMware构建串口通信环境的方法以及具体实现过程。