Cu基络合物催化甲醇液相氧化羰化反应

针对甲醇液相氧化羰基化法合成碳酸二甲酯(DMC)工艺,开发了新型Cu基络合催化剂(CuB rnLm)。对CuB rnLm催化剂的活性及其稳定性进行了研究。实验结果表明,采用该催化剂,甲醇转化率和DMC选择性较高;元素价态和物质结构分析表明,CuB rnLm催化剂循环使用5次后仍保持较好的稳定性。采用正交设计和中心响应曲面法设计实验,并使用S tatistica软件进行统计分析,寻求出反应的主要影响因素,并得到优化的工艺条件:反应温度100~110℃、反应压力3.0~3.5M Pa、反应时间4~6h、CuB rnLm催化剂质量浓度(以甲醇的体积计)0.15~0.20g/mL。在此工艺条件下,甲醇转化率可达23%以上,DMC的选择性为96%~98%。     

Field Static Load Test on Kao-Ping-Hsi Cable-Stayed Bridge

Field load testing is an effective method for understanding the behavior and fundamental characteristics of a cable-stayed bridge. This paper presents the results of field static load tests on the Kao-Ping-Hsi cable-stayed bridge, the longest cable-stayed bridge in Taiwan, before it was open to traffic. A total of 40 loading cases, including the unit and distributed bending and torsion loading effects, were conducted to investigate the bridge behavior. The atmospheric temperature effect on the variations of the main girder deflections was also monitored. The results of static load testing include the main girder deflections, the flexural strains of the prestressed concrete girder, and the variations of the cable forces. A three-dimensional finite-element model was developed. The results show that the bridge under the planned load test conditions has linear superposition characteristics and the analytical model shows a very good agreement with the bridge responses. Further discussion of deflection and cable forces of the design specifications for a cable-stayed bridge is also presented.     

井下套管阀研究及室内试验

随着欠平衡钻井技术的深入研究和推广应用,全过程欠平衡钻井技术已成为研究热点。除了常规的欠平衡装备外,全过程欠平衡钻井还需配备井下套管阀,为此,研制了一种双液控井下套管阀。为检验该阀的使用可靠性,进行了全面的室内试验和测试,试验内容包括压力密封能力,高压、有流动情况下阀板关闭的动作准确性,模拟现场阀板下憋压时打开阀板的作业程序,检测在各种密封压力时阀的微泄漏量。试验结果表明,该阀达到设计要求,能够满足全过程欠平衡作业的工艺要求。     

下一代无线通信概念和技术

下一代无线通信(NextG:Next-generationwireless)的主流是随时随地的无线通信系统和无缝的高质量无线业务。概述了随时随地的无线通信和业务发展情况,并且介绍了为下一代无线通信的发展提供基础的关键技术。     

一种实现非等带宽多载波调制的新方法

传统的多载波调制都是采用对传输信道进行等带宽划分的方式。为了更好地适应信道传输特性，一个很有应用前景的发展方向是采用非等带宽划分信道的多载波调制方式。本文提出了一种利用正交小波包变换实现的非等带宽划分信道的多载波调制方法。理论分析和实验结果表明，这种方法对于提高信道的传输性能有很大的潜力。     

Juvenile competence to stand trial evaluations: A survey of current practices and test usage among psychologists.

What is the current standard of practice for evaluations of juvenile competence to stand trial (JCST)? The present study surveyed psychologists regarding the practices used when conducting JCST evaluations. Respondents rated the importance of 17 elements that might be included in a JCST evaluation report. Of these elements, 7 were considered essential by 70% or more of respondents, with 9 additional elements rated as either essential or recommended. A majority of respondents felt that the use of psychological and forensic instruments was important. A list of tests used is provided, and the implications for the development of standards and policy are discussed to provide practitioners with additional knowledge that will help to further the state of the discipline. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dynamic response and behavior of reinforced concrete slabs under impact loading

Reinforced concrete slabs are among the most common structural elements. In spite of the large number of slabs designed and built, the effect of their details on their behavior under impact loads are not always appreciated or properly taken into account. This experimental study was aimed at understanding the dynamic behavior of structural concrete slabs under impact loading to improve the state of the art of protective design. This study investigated the effects of different types of slab reinforcements and the applied impact loads on the dynamic response and behavior of reinforced concrete slabs.     

弹力竹节牛仔布织造工艺优化

介绍了弹力竹节牛仔布的生产工艺 ,同时对KT36 8剑杆织机织造该织物的工艺进行了优化研究     

Recent advances in isotropic conductive adhesives for electronics packaging applications

Isotropic conductive adhesives (ICAs) have recently received a lot of focus and attention from the researchers in electronics industry as a potential substitute to lead-bearing solders. Numerous studies have shown that ICAs possess many advantages over conventional soldering such as environmental friendliness, finer pitch printing, lower temperature processing and more flexible and simpler processing. However, complete replacement of soldering by ICAs is yet not possible owing to several limitations of ICAs which are mainly related to reliability aspects like limited impact resistance, unstable contact resistance, low adhesion and conductivity etc. Continued efforts for last 15 years have resulted in development of ICAs with improved properties. This review article is aimed at providing a better understanding of ICAs, their principles, performance and significant research and development work addressing the technological utility of ICAs.     

In Situ Performance Testing of Deteriorating Water Tanks for Durability Assessment

Reports of failure of existing concrete structures due to a lack of durability, rather than a deficiency in structural strength, has made concrete technologists, engineers, and researchers focus research on the parameters influencing durability performance with respect to time. Systematic performance monitoring, with respect to chosen durability parameters of existing concrete structures, will decide the direction of future research in this area. Inferences based on laboratory simulations and testing need to be confirmed by in situ field measurements and studies. In situ condition rating and performance monitoring surveys have been conducted by many researchers, scientists, and professional associations, and reported in literature. Inferences of few such studies are summarized and discussed. Deterioration of concrete structures constructed in recent times is observed at relatively faster rates, and has been mainly attributed to cracking. Cracking is associated with the use of faster-hydrating portland cements with increased fineness and the tricalcium silicate (C3S) content to support the high speed of modern construction. In the present research, a case study of deteriorated water tank structures situated in the semitropical region of India is presented. Some selected parameters—such as concrete cover, carbonation depth, chloride concentration, compressive strength, etc. which influence long term durability of structures—have been measured.