天津通信企业IT信息网络支撑平台

从系统建设背景、关键技术、创新点及应用情况等方面介绍了天津市通信公司企业IT信息网络支撑平台是一个统一、高效、简洁的综合业务网络平台。     

无线技术的新领域--WUSB

无线USB(WUSB)技术是一个全新的无线传输标准.实现USB(通用串行总线)无线化以后,既可以保持有线USB的高速传输等优点,又可以去掉电缆的羁绊,给各种设备带来更大的便捷和移动性.文中首先介绍了WUSB技术的由来--UWB技术规范的标准化难以确定,然后对WUSB技术的规范标准进行了阐述,最后概述了WUSB技术的发展现状及目前和今后的技术研发重点,并对WUSB的发展前景进行了展望.     

An investigation into physicochemical characteristics of ash produced from combustion of oil palm biomass wastein a boiler

Ash derived from combustion of Malaysian oil palm biomass (empty fruit bunches consisting of fibers) was physically and chemically characterized in order to provide a comprehensive understanding of its specific properties in terms of toxicity, compositions and reusability. Principal analyses conducted include particle size distribution, scanning electron microscopy, elemental dispersive X-ray, elemental analysis, toxicity characteristic leaching procedure (TCLP) as well as thermogravimetric, X-ray diffractometry and Fourier-transform infrared analyses. TCLP result indicated that the oil palm ash (OPA) should not be classified as toxic wastes in terms of heavy metal leachability since leachable copper, cadmium, lead and nickel concentrations were detected below the stipulated leachability limits. It was determined that the OPA contained high amount of potassium as well as presence of silica which implied its suitability to be reused as crude fertilizer or cement replacement material.     

有机羧酸钠盐对PET结晶和熔融行为的影响

采用差示扫描量热仪研究了5种具有不同取代基的苯甲酸钠盐作为结晶成核剂对聚对苯二甲酸乙二醇酯（HET）结晶和熔融行为的影响，并同滑石粉进行了对比。结果表明，成核剂的加入能明显改变PET的结晶和熔融行为。苯甲酸钠、对苯二甲酸甲酯单羧酸钠和对羟基苯甲酸钠提高既汀的熔融结晶温度（Tc）分别达22．93、21．7和19．37℃，但使PET降解严重；对苯酚钠甲酸钠能够提高Tc达17．75℃且对PET相对分子质量影响很小；对苯二甲酸二钠成核作用最差。低于滑石粉。此外，成核剂的成核能力越强，PET双熔融峰中的低温峰顶温度就越高。     

控制性水库建设模式研究

水库梯级（尤其是控制性水库梯级）的建设在西南水电开发中具有举足轻重的地位。但控制性水库梯级一般位于河流上游，为获得需要的调节库容，要求有较高的坝，从而增加筑坝的难度，水库淹没较大，相应的投资亦较大，故经济性相对于其它类型的电站较差。为促进控制性水库梯级的建设，有必要对控制性水库的建设模式进行研究，寻求其可能的投资分摊方式。本文在合理核算上游控制性水库梯级对其下游梯级受益电站补偿调节效益的基础上，对上游控制性水库梯级建设模式进行了研究，提出了控制性水库梯级几种可能的建设投资分摊模式。     

Analysis of S-SEED''s characteristics in optical switch

This article introduces the basic structure of a symmetric self-electrooptic effect device （S-SEED）, and applies the Kirchoff＇ s current law and a purely equivalent capacitive model, to analyze S-SEED＇s switch characteristics. Linear approximation and N-segment approximation are utilized to obtain S-SEED＇s voltage-time （V-T） and characteristics. Theoretical analysis is verified by simulations, and the results demonstrate that the precision of S-SEED＇s switch time can satisfy the requirement in applications with linear approximation. Moreover, the simulations compare S-SEED＇s switch characteristics with different input powers and input contrast ratios, which reveal that increasing input contrast ratio is an effective way to improve S-SEED＇s switch characteristics.     

Cooperative cache-based data access in ad hoc networks

Cooperative caching, in which multiple nodes share and coordinate cached data, is widely used to improve Web performance in wired networks. However, resource constraints and node mobility have limited the application of these techniques in ad hoc networks. We propose caching techniques that use the underlying routing protocols to overcome these constraints and further improve performance.     

现代电子产品焊接质量的检测技术

介绍了现代电子产品焊接质量的检测技术,以及用于检查焊点质量和组装板(SMA)功能的测试仪器的工作原理及测试能力.目前常见和广泛使用的焊接质量检测方法是人工目测检查,其主要问题是其主观性,只能用来检测电子元件的形状、尺寸、颜色、表面特征及焊点的外观质量;自动光学检测(AOI)可以在整个过程中发现和纠正缺陷,但只是外在的焊点缺陷;激光/红外线组合式检测系统、X射线检测系统可以分析焊点微米级水平的缺陷,能找出其他检测所不能可靠地发现的缺陷,包括空洞、焊点形状差和冷焊锡点等;另外,X射线检测系统能一次测试单面或双面电路,准确地定位缺陷,获取工艺参数,例如锡膏厚度等.