有机硅橡胶在高压产品中真空灌封工艺应用

本文通过高压产品中高压功率管器件为研究对象,通过采用道康宁和国产有机硅橡胶开展真空灌封方式满足了该高压器件的绝缘需求。重点介绍了真空灌封工艺路线的确认以及关键工序控制方式,经过高低温循环试验以及低气压放电试验验证,该灌封技术可以满足该高压器件的绝缘防护要求,为高压产品的研制提供工艺支撑能力。     

灌封用缩合型硅胶的高温高湿可靠性研究

通过长期双85试验,对缩合型硅胶及用其灌封的PC材料的性能变化进行了研究,分析了PC材料出现"龟裂"现象的原因,进而评估它们在高温高湿环境下的可靠性。结果表明,"龟裂"现象是由于在高温高湿的环境下PC外壳与缩合型硅胶脱出的醇反应所导致的,且该"龟裂"现象会降低PC材料的力学性能,可通过该力学性能的变化来评估传感器产品对高温高湿的长期可靠性。     

某高温试验能力验证的不确定度评定

本文主要以实验室参加的一次高温试验能力验证计划为例,对影响高温试验的不确定度来源进行了分析,对各类不确定度进行了具体评定,为其他相关实验室高温试验的不确定度评定提供参考。     

一种AI芯片模组低温加热技术仿真设计研究

本文针对某商用等级AI芯片模组无法在-40℃低温环境下启动的问题,提出了一种使用电阻加热膜对芯片低温加热的技术方法,并通过FloTHERM仿真软件对不同功率的加热膜进行瞬态仿真分析,评估120s后AI模组壳体的温升情况,依据仿真结果确定加热膜功率,并在此基础上搭建试验平台进行验证。试验结果表明,当加热膜功率40W时,能够满足AI芯片模组的温升和120s内启动的技术要求,并且仿真结果和试验结果相吻合。本技术方案对军用环境下使用商用等级芯片的低成本方案具有一定指导意义。     

泥水盾构废弃泥浆絮凝脱水机理及影响因素分析

为明确泥水盾构废弃泥浆固液分离性能,提高泥浆固液分离效率,采用化学絮凝的方法对建筑废弃泥浆快速泥水分离性能进行了试验研究,开展了不同种类聚丙烯酰胺(PAM)作用下废弃泥浆絮凝沉降试验、颗粒级配试验及浊度试验研究,考察了药剂种类(APAM、NPAM、CPAM)、分子量及用量对废弃泥浆絮凝沉降特性的影响规律。试验结果表明：APAM和NPAM对废弃泥浆固液分离效果显著,CPAM对废弃泥浆并无明显絮凝作用;对于APAM而言,当其分子量分别为1200万,1600万和1800万时,废浆絮凝效果最佳时的添加量分别为0.35g/L、0.3g/L和0.25g/L;对于NPAM而言,当其分子量分别为1200万,1600万和1800万时,废浆絮凝效果最佳时的添加量分别为0.3g/L、0.3g/L和0.25g/L,且在最佳添加量的情况下,底泥体积、底泥含水率和上清液浊最小,泥浆粒径参数D50最大;APAM与废弃泥浆颗粒之间的作用方式主要是“吸附架桥连接”,NPAM与废弃泥浆颗粒之间的作用方式主要是“电性中和”与“吸附架桥连接”。     

柑橘皮中果胶提取条件的研究

利用酸性水解乙醇沉淀法提取果胶,分别测定了不同的浸泡时间、酸碱度及水解温度对果胶产率的影响.结果表明:浸泡时间与水解时间过长或过短,酸碱度及水解温度过高或过低,果胶的产率均不高,只有浸泡时间在2h左右、水解时间在2～2.5h、pH在2～3之间、水解温度在80～95℃时果胶的得率最大.     

采油作业“三废”控制技术研究与应用

针对采油作业产生的废酸、固废、废水处理成本高、技术不成熟等问题,研发改性废酸降压增注、深部调剖技术;高比重污泥悬浮研磨后的固废处理技术;低耗水打塞、原井液+CaCl2压井、原井液处理再利用技术,减少了"三废"的产生,解决了"三废"环保处理费高等问题,消除了环保隐患,实现了清洁生产,环境效益显著。     

强碱三元复合驱采出水处理工艺技术研究

常规的"沉降+过滤"方式用于三元复合驱采出水处理,聚合物或黏度对石油类和SS的高效去除有较大影响,处理思路应以脱稳降黏为主。文章探索了采用的"气浮沉降+生化氧化+高级氧化+二级过滤"工艺,达到石油类≤800 mg/L,SS≤350 mg/L,黏度≤12 mPa·s,PAM≤800 mg/L,使采出水处理稳定达到回注水要求,降低滤池冲洗难度,降低了固液分离难度,提高了工艺运行稳定性。对于采出水进一步开展膜深度处理,采出水实现回注低渗透层等具有重要意义。     

极端天气与全球变暖

<正>现在谈天气已经不再是见面时的寒暄,而是一个不轻松的话题。七月的北方高温,南方暴雨,媒体常用"创纪录"、"N年不遇"等词汇。面对     

东菱振动让世界同行瞩目——记苏州东菱振动试验仪器有限公司自主创新历程

(本刊讯)2006年1月16日,苏州东菱振动试验仪器有限公司在苏州市喜来登大酒店召开了"世界最大级35吨电动振动试验系统成果汇报暨东菱公司第四届国际营销大会",并同时进行了"东菱工程技术中心奠基典礼",本次会议是2006年国内乃至国际力学环境试验领域规模最大与会人数最多的一次技术研讨盛会.     

焊点热疲劳失效原因分析

某PCBA样品在使用约半年后出现功能失效,该PCBA在封装后进行整体灌胶,将失效样品剥离,发现部分器件直接脱落,通过表面观察、切片分析、EBSD分析、应力分析、热膨胀系数测试等手段对样品进行分析,结果表明:各封装材料存在热失配,且焊点缺陷较多且存在应力集中区,加速焊点的疲劳失效进程,导致PCBA功能失效。     

空调器印剧电路板(PCB)无铅焊点寿命评估研究

由于无铅焊料的应用,无铅焊点的可靠性问题得到了关注.本文针对无铅焊点的空调器印刷电路板(PCB),结合实际使用条件,采用加速寿命的方式,测试了焊点的寿命.并针对温度循环条件下的焊点,使用有限元模拟技术计算测定了其寿命,并与实验的结果进行了比较,取得了较吻合的结果.     

基于子模型的电子封装焊点寿命预测方法研究

在向无铅化过渡的过程中,封装材料与工艺改变所带来的最突出的问题之一就是无铅焊点的可靠性问题。由于焊点区非协调变形导致的热疲劳失效是电子封装焊点的主要失效形式。到目前为止,仍无公认的焊点寿命和可靠性的评价方法。本文采用统一型粘塑性本构模型描述SnAgCu焊点的变形行为,在对焊点可靠性分析的基础上采用基于能量的寿命模型进行焊点寿命预测;在有限元方面采用子模型的处理技术,并采用节点平均化以及体积平均化方法计算寿命模型相关参数。力图从理论方面和有限元处理技术方面改进以达到提高焊点寿命预测效率及预测精度的目的。     

Growth of the Decision Tree: Advances in Bottom‐Up Climate Change Risk Management

There has recently been a return in climate change risk management practice to bottom‐up, robustness‐based planning paradigms introduced 40 years ago. The World Bank's decision tree framework (DTF) for “confronting climate uncertainty” is one incarnation of those paradigms. In order to better represent the state of the art in climate change risk assessment and evaluation techniques, this paper proposes: (1) an update to the DTF, replacing its “climate change stress test” with a multidimensional stress test; and (2) the addition of a Bayesian network framework that represents joint probabilistic behavior of uncertain parameters as sensitivity factors to aid in the weighting of scenarios of concern (the combination of conditions under which a water system fails to meet its performance targets). Using the updated DTF, water system planners and project managers would be better able to understand the relative magnitudes of the varied risks they face, and target investments in adaptation measures to best reduce their vulnerabilities to change. Next steps for the DTF include enhancements in: modeling of extreme event risks; coupling of human‐hydrologic systems; integration of surface water and groundwater systems; the generation of tradeoffs between economic, social, and ecological factors; incorporation of water quality considerations; and interactive data visualization.     

Proposition 65 warning regulations must change—and soon!

Proposition 65 (Prop 65) is very much a part of the “right‐to‐know” landscape in California and, as we all know, Prop 65 warnings are especially visible in that state. This much is clear. What may be less clear are the sweeping changes in the “clear and reasonable warning” requirements now scheduled to take effect from August 30, 2018. This date may seem like a long way off, but it is right around the corner in terms of coming into compliance with these dramatic changes. This Washington Watch column summarizes the new warning requirements and the reasons why companies need to focus now on these changes.     

基于整车道路试验的水箱新型热循环试验方法

基于B公司的整车道路耐久试验中水箱的失效模式,综合分析热应力导致的失效机理,结合实车水箱内部实际温度交变幅度和温度交变频率,设计了一种针对水箱热应力失效的新型热循环台架试验方法。试验结果表明本新型热循环试验工况能对失效模式进行很好的复现。通过台架试验,证明了本方法的可行性。     

A green garden on red clay: creating a new urban common as a form of political gardening in Cologne,Germany

In March 2012, a brownfield site in Cologne was transformed into “a green garden on red clay”, when a community garden called NeuLand (new land) was created. This paper investigates in how far NeuLand is typical for a new form of political engagement 2.0, focused on local problems at people's doorstep rather than global critiques of political systems, which finds its expression in direct actions typical for the networked society, e.g. “green flash mobs.” Its potential to provide a blueprint for imagining and enacting alternative futures and new ways for citizens to claim their “right to the city” is being assessed. NeuLand provides an experiment with new forms of (urban) commons and possibly a (re)turn to the “liveable city” to replace the current neoliberal ideal of the “entrepreneurial city” [Harvey, D., 1989. From manageralism to entrepreneuralism: the transformation of urban governance in late capitalism. Geografiska Annaler, Series B, Human Geography, 71 (1), 3–17], developing new solutions to problems of urban management and city development that extend beyond the voluntary engagement of citizens within the logic of the neoliberal “big society.” Extending the scope beyond the analysis of urban gardening projects as examples of sustainable food production, or as vehicles for fostering community cohesion, integration or social capital, the NeuLand experiment is linked to wider debates of alternative and more sustainable socio-ecological futures than those currently practised in the newly “neoliberalizing cities” of Germany.     

以就业为导向的高职高专数学课程改革之实验课探究

本文就“以就业为导向的高职高专数学课程的改革与实践”的子课题—数学实验课程进行探究，对高职高专数学实验课程教学的意义和目的、模式和原则、任务和设计，进行了阐述。     

灌封材料与环境适应性

本文简述了几种灌封材料的特性,包括环氧树脂灌封胶、聚氨酯灌封胶和有机硅灌封胶。并针对水、辐射、温度/热、氧和臭氧、微生物因素和机械应力等环境因素对灌封料的影响进行分析。     

Applying the triple bottom line: Telework and the environment

The “triple bottom line” approach emphasizes not only economic goals, but social and environmental objectives as well. The “telework” option—in which employees work from home or a satellite office rather than from a central location—would appear to advance all three of these aims. But a close look at the specifics of teleworking makes clear that more data are needed to determine its ultimate impact. Moreover, despite its apparent advantages, teleworking is gaining acceptance less quickly than might be expected. For these reasons, telework offers a fascinating case study in the difficulties of applying the triple bottom line concept.© 1999 John Wiley & Sons, Inc.