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Abstract: Polyphenylacetylenes were synthesized by ［Rn(nbd)Cl］2 and WCl6/Ph4Sn catalyst systems in N2 at room temperature.Polymers with high yield and high molecular weight were obtained.Their structures were characterized by UV,IR,NMR and GPC,respectivel
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文摘:使用有机金属铑、金属钨/四苯基锡催化剂体系聚合苯乙炔，分别获得了高产率和高分子量的聚苯乙炔.使用UV，IR，NMR，GPC等分别对聚合物结构进行了表征.采用不同波长的激发光对聚合物荧光性能进行研究，详细分析了聚合物结构与荧光性能之间的关系.研究结果发现，不同聚合物结构对聚合物荧光性能产生很大影响，规整性高的聚合物，将有较高的发光量子效率；聚合物规整性差，将可能导致多个荧光发光结构点，其荧光强度降低.聚合物荧光光谱研究将对某些共轭聚合物结构的规整性分析提供一些有用的信息. |
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Abstract: Portasystemic shunts is a very important Pathophysiologic Changes in portal hypertensive patients, The measurement of portasystemic shunts is important to choose a decent operation pattern, determine the diameter of TIPSS stents, prevent post-op
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文摘:肝外门-体分流是门脉高压症形成过程中最为重要的病理生理现象，测定肝外门-体静脉分流量，对治疗门脉高压症手术方式选择、决定手术分流道的大小、防治肝性脑病以及判断患者预后均有重要的指导意义。 |
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Abstract: Positron spectroscopy is a new and sensitive microanalytical probe for characterization of polymer microstructures.We report recent advances in this area,including studies on the free volume properties,structural transition,miscibility of blendi
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文摘:简要介绍了近年来正电子谱学在聚合物微结构研究中的主要应用及进展.大量实验事实表明，正电子谱学是表征高聚物微结构的极灵敏方法. |
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Abstract: Poverty in America has grown persistently throughout the twentieth century.
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摘要：美国的贫困现象在整个20世纪持续增长。 |
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Abstract: Power quality and its monitoring technique is the important research area in electrical engineering nowadays.
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摘要:电能质量监测是当前电工领域的研究热点。 |
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Abstract: Precast floorslabs are widely used in residential buildi ngs in order to quicken the progress of construction.Yet some quality problems accoringly arise,one of which is the fissure along the splice of the precast floor slab.This essay analyses t
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文摘:在住宅的设计与建设中大量采用预制楼板结构，虽然加快了施工进度，但也出现了一些问题，预制楼板板缝方向产生裂缝就是其中之一，本文对其原因进行了分析，并提出了有效的防治措施. |
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Abstract: Precisely predicting the amount of gas emitted from the coal face is of great importance in the design of mine and production safety.
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文摘:正确预测瓦斯涌出量，对于指导矿井设计和安全生产有重要意义。 |
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Abstract: Presented is a newly developed measuring &, control system used for internal combustion engine rig test.
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文摘:介绍了一种新开发的适用于发动机鉴定试验的自动测量控制系统。 |
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Abstract: Presents the model established for calculation of reliability of connecting rod fatigue strength, and stress analysis made with the connecting rod body of diesel engine,and the reliability calculations made with the connecting rod of 6200ZCL die
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文摘:连杆的主要破坏形式是疲劳破坏，疲劳破坏是连杆按强度失效的主要故障模式.本文根据机构可靠性的基本原理，建立了连杆疲劳强度可靠性的计算模型.对直列式柴油机连杆杆身进行了应力分析，并结合6200ZCL型柴油机连杆的具体实例，进行了无限寿命下的疲劳强度可靠性计算，所得结果与实际工程情况相符.阐明了所提供方法的具体应用，这种方法对其它寿命很长的机构构件同样适用. |
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Abstract: Pressure separation is usually controlled by the following factors, such as subsidence rate, sediment types and diagenesis during the diagenetic evolution, as a result the pressure gradient is uncontinuous.
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文摘:地层压力分隔化是由于沉积物在成岩演化过程中受各种因素，如沉积速率、沉积物类型以及成岩作用的影响，使地层中的流体压力梯度呈现出随深度变化不连续的一种现象。 |
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Abstract: Principles of nanometer materials science,basic methods preparing nanometer materials and their application prospects in petrochemical catalysts, assistants and additives, were introduced together with practical examples of initial study and app
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文摘:对纳米材料科学的基本原理、纳米材料制备的一些方法，以及纳米材料在石油化工催化剂、助剂和添加剂中的应用前景做了介绍，并列举了一些处于起始阶段的研究和应用实例。 |
