混凝土结构的压电声波检测分析

本文介绍了混凝土结构的压电体波和表面波检测的主要进展,对两种压电声波检测的优缺点进行了总结。体波检测设备一般埋入混凝土内部,需要选择合理的检测部位,检测结果较为精确;声表面波检测无需选择特定的部位,但是检测深度有限。在实际检测工作过程中,可以联合两种方法相互验证。     

Effect of chemical phosphorylation on solubility of buffalo milk proteins

Buffalo milk proteins (casein, co-precipitate or whey protein concentrate) were phosphorylated with phosphorus oxychloride (POCl₃) at three different pH values (5.0, 7.0 and 9.0). The solubilities of phosphorylated milk proteins were examined over the pH range 3.0–9.0 in water and ionic (0.1 m NaCl or 10–70 mm Ca²⁺) systems. The solubilities of buffalo milk proteins decreased at pH 3.0, while there was an increase in the solubilities of casein and co-precipitate near their isoelectric points upon phosphorylation. Solubilities of these phosphorylated milk proteins were pH dependent in 0.1 m NaCl but there was a decrease in their solubilities with increase in calcium ion concentration. This alteration could be due to the shifting of isoionic points of phosphorylated buffalo milk proteins towards acidic pH.     

Development of polyurethane elastomer composite materials by addition of milled fiberglass with coupling agent

Polyurethane elastomer composites were developed using milled fiberglass and their mechanical properties were studied. In particular, the organically chemical treatment of the milled fiberglass was investigated in detail. It was demonstrated that both strength and toughness of the resulting elastomer composites were improved considerably with the addition content of fiberglass. Furthermore, it was indicated that the optimal properties can be achieved by the proper addition of milled fiberglass that was chemically treated using coupling agent.     

Wrinkling of corrugated skin sandwich panels

Compression wrinkling of composite sandwich panels with corrugated skins was investigated numerically, analytically and experimentally. Semi-circular and sine-wave shaped corrugations were studied. The corrugations significantly increased wrinkling strength when compared with equal mass flat panels. Semi-circular corrugations proved to be highly preferable to sine-wave shaped corrugations due to localized buckling in the latter. Over 40 fiberglass and foam core sandwich specimens were manufactured with semi-circular skin corrugations. These specimens were tested to failure, providing confirmation of the numerical and analytical results.     

基于Java点对点通信技术的DES密钥交换

介绍了使用Java的点对点通信技术,基于Diffie-Hellman规则,给出了IBM DES密钥交换的总体方案、算法和应用程序,详细说明了其中涉及的主要技术和方法,同时给出了在PC机上用二进制指数分解法实现大数模运算的算法分析和实现方案。     

防雷接地在楼宇建筑中智能化系统的作用

雷电产生是由于云层中电荷中和作用是会产生大量的热量和光,雷电现象属于一种自然现象,目前人类生活中无法避免这种现象,只能在实际运用中做防护处理。浙江宁波作为一个雷电高发地区,每年由于雷击现象直接或间接所造成的经济损失不计其数。雷击危害一般分为两大类:1)雷直接击中在建筑上发生热效应和电动力作用,2)雷电二次作用即雷电流产生静电和电磁感应。防雷设施主要包括内部防雷和外部防雷,外部防雷主要由避雷针、引下线、接地体、法拉第等部分组成;内部防雷主要由电源线防护、信号线防护、均压等电位等部分组成,落实每个部分对防雷起着重要作用,缺一不可,这对于保障楼宇建筑中智能化设备的安全,减少经济损失,有着深远的意义。     

MMA7361L的高精度角度检测平台设计

倾角是许多控制系统中需要测量的一个重要参数。针对倾角测量,设计了一种基于ARM微控制器和加速度传感器的角度测量平台。该平台采用基于ARMCortex—M3内核的STM32F103VE为数据处理的核心,利用高精度加速度传感器MMA7361L为测角传感器,同时配置液晶屏和小型键盘实现了人机交互。该平台具有测量精度高、灵敏度高、价格低的特点,应用前景广阔。     

基于uIP与AJAX的动态Web服务器设计

针对远程信息监测系统中数据的实时采集更新问题,将AJAX和CGI应用到嵌入式Web服务器的设计中,实现了服务器与浏览器之间的动态信息交互。本文首先分析了uIP协议栈,并在协议栈之上设计了Web服务器,然后利用CGI服务程序处理来自客户端的XMLHttpRequest对象请求,实现动态Web功能。现场实验结果表明,嵌入式Web服务器降低了服务器端的资源开销,提高了响应速度。     

电火花成形机主轴电极头的流固耦合分析

电火花成形机主轴电极头在回退、直至完全离开工作液的过程中,会受到工作液对其表面产生的阻力作用.研究主轴电极头所受的液体阻力,为主轴支承件的有限元分析和优化设计提供详实可靠的理论依据.     

混凝沉淀-兼氧-SBR-活性炭滤池工艺处理化工废水

本文介绍了采用混凝沉淀-兼氧-SBR-活性炭滤池工艺处理化工废水，设计处理规模为200m^3／d。当进水水质为pH7．1，COD2305mg／L，BOD5970mg／L，石油类40．8mg／L，挥发酚0．222mg／L条件下，经本工艺处理后，总排放口出水水质为pH7．9，COD77．9mg／L，BOD511．7mg／L，石油类2．62mg／L，挥发酚0．023mg／L。实践证明，该工艺技术可靠，运行稳定，有较好的经济和环境效益。