四川盆西平原区裸土扬尘中Pb、Cd化学形态的生物有效性

为探究四川盆西平原区裸土扬尘中Pb、Cd总质量分数与其生物有效性的规律,在构建的"阳离子型污染物土壤表层运移行为研究系统"内进行模拟起尘试验,对土壤样品进行Pb、Cd模拟污染试验,结果表明:试验条件下,四川盆西平原区裸土扬尘颗粒物中Pb、Cd的总质量分数随着粒径的减小而增大,其中Pb的化学形态以碳酸盐结合态为主(44....     

源霸二线相间间隔棒掉串分析及对策

本文对大同超高压供电公司运行维护的源霸二线发生断裂相间间隔棒的运行、结构、强度、安装等情况进行了分析,并在此基础上提出了防止相间间隔棒断裂反事故措施。     

论我国炼油厂和管道运输的可持续发展

论述了炼油厂大型化的优点：大型炼油厂的经济及环保指标均优于中小型炼油厂;大炼油厂采用先进的工艺和环保措施效果显著;可持续发展潜力比小炼油厂大。针对我国油田及进口油港的分布,提出建设13个大型炼化中心取代目前分散布置的大中小炼油厂的设想。为配合大型炼化中心的建设,我国的以原油运输为主的管道工业今后应将改建为以成品油运输为主。指出了今后需要研究克服的难题：卡斯特溶洞地质地区管道穿越问题;高黏易凝原油的常温输送技术;研究阶梯输送调度技术;研究开发耐用的适用于中小口径旧管道改造的内防腐—减阻涂层技术;汽油及轻质油的全密闭储存技术;研究无外漏的全密闭绿色泵及绿色压缩机;原油管道改造为成品油管道技术等。     

Phase change memory alloys: GST cell array characterization using picosecond ultrasonics

Phase change random access memory alloys (PRAM or PCM) are a class of non-volatile memory that is thought as viable alternatives to flash memory technology or to supplement other memory technologies depending on the end applications and its key performance requirements. Ge₂Sb₂Te₅ alloy (GST) is the most widely used chalcogenide material for PCM application, and has many unique properties, including strong temperature-dependent film properties, low thermal conductivity, and high electrical resistivity. Picosecond ultrasonics was used to make non-contact, non-destructive measurements of GST films on blanket wafers and directly on product wafers. On-product wafer measurements were made on various via array (0.5 μm and 1 μm between cell edges with CD size from 250 to 800 nm). Measurements have shown excellent correlation to cross-section SEM and were consistent with CMP polish times for both blanket and pattern wafer measurement. Excellent repeatability based on extensive measurements demonstrates the capability and reliability of picosecond ultrasonic technology. Picosecond ultrasonic measurements also provide rapid characterization across the whole wafer at production-worthy throughputs.     

Impedance match for Stirling type cryocoolers

Impedance match in Stirling type cryocoolers is important for the compressor efficiency and available acoustic power. This paper generalizes the basic principles concerning the efficiency and acoustic power output of the linear compressor. Starting from basic governing equations and mainly from the viewpoint of energy balance, the physical mechanisms behind the principles are clearly shown. Specially, this paper focuses on the impedance match for an existing compressor, where the current limit and displacement limit should also be taken into consideration when selecting a suitable impedance. Some case studies based on a commercial compressor are also provided for a deep understanding.     

Mechanically strong conducting hydrogels with special double-network structure

Mechanically strong conducting hydrogels composed of poly(acrylamide) (PAAm) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) have been synthesized through the construction of a special double-network (sDN) structure. The novelty of the sDN hydrogels lies in the introduction of PEDOT-PSS semi-interpenetrating polymer network (semi-IPN) hydrogel as the second network. Based on the experimental results and the double-network theory, an additional strengthening effect resulting from the formation of the PEDOT clusters in a three-step fracture process is proposed. The applicability of as-prepared PAAm/PEDOT-PSS sDN hydrogels in electromechanical actuators is also briefly discussed.     

微风细雨:都江堰虹口香溪堂设计随笔

<正>都江堰虹口距成都市约80km,因避暑及漂流而成为成都的旅游胜地,生态旅游中心选址于虹口风景区深溪沟。项目分两期,一期为深溪沟接待点,由香溪行馆(别墅区)和香溪堂(服务配套建筑,190m~2)组成,二期为虹口旅游服务中心及酒店。香溪堂作为接待、休闲之用,规模很小,功能简单,但业主极为重视,把它作为二期启动前的形象展示,希望设计理念先进,独具个性。业主于2007年10月正式委托我们设计一期工程,原计划2008年6月动工。5月12日突如其来的汶川大地     

地下工程抗浮加固设计

地下工程的抗浮设计非常重要,往往决定着工程的成败。本文所述案例由于原设计未充分考虑地下水的影响而致使事故的发生。笔者通过对事故现象的分析,找出了造成事故原因,从而采取经济合理的加固方案使该工程达到了较为满意的经济和社会效益。     

弯剪作用下建筑物单桩桩基计算方法初探

本文通过分析弯剪作用下的建筑桩基的水平承载力计算的规范方法及支护结构中的挡土桩的计算方法和对弯剪作用下建筑桩基的受力状态的定性分析,给出了该种工况下的单桩计算的建议模型供同仁参考指正。     

Unsupervised adaptation of electroencephalogram signal processing based on fuzzy C‐means algorithm

This paper studies an unsupervised approach for online adaptation of electroencephalogram (EEG) based brain–computer interface (BCI). The approach is based on the fuzzy C‐means (FCM) algorithm. It can be used to improve the adaptability of BCIs to the change in brain states by online updating the linear discriminant analysis classifier. In order to evaluate the performance of the proposed approach, we applied it to a set of simulation data and compared with other unsupervised adaptation algorithms. The results show that the FCM‐based algorithm can achieve a desirable capability in adapting to changes and discovering class information from unlabeled data. The algorithm has also been tested by the real EEG data recorded in experiments in our laboratory and the data from other sources (set IIb of the BCI Competition IV). The results of real data are consistent with that of simulation data. Copyright © 2011 John Wiley & Sons, Ltd.