Toughening mechanisms in commercial thermoplastic polyolefin blends

Impact fracture mechanisms in a variety of commercially available and experimental thermoplastic polyolefin (TPO) blends were studied using the double‐notch four‐point‐bend Charpy impact test, followed by microscopy observations. It was shown that the failure mechanisms and the sizes of the subcritically formed crack‐tip damage zone before fracture were quite different among the TPO systems investigated. The room temperature Izod impact strengths of the TPOs investigated were found to correlate qualitatively well with the sizes of the damage zone. At room temperature the main fracture mechanisms observed in TPOs include matrix crazing, particle–matrix debonding, rubber particle internal cavitation, and shear banding. At low temperature (−40°C), the operative fracture mechanisms in TPOs are limited only to crazing, particle cavitation, and debonding. A strategy for improving impact strength without sacrificing scratch/mar resistance of TPOs is discussed. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 311–319, 2000     

我国压敏胶粘带的现状及发展

报道了我国压敏胶粘带的需用量、及应用市场。 1998年销售量 2 4.9亿m2 ,比上一年增长 3.75 %。包装用占份额48.5 % ,标签及印刷占 17.2 % ,医疗卫生用占 11.2 5 %。还介绍了压敏胶粘带的生产设备 ,基材 ,离型纸的技术现状 ,并提出正在或期待开发的项目     

Analysis of the Taber Test in Characterization of Automotive Side Windows

The Taber test, as described in ASTM D-1044, combined with haze-level measurement, as described in ASTM 1003, is a commonly used method in many industries to evaluate resistance of material surfaces to abrasion. Attempts were made to use the Taber test to characterize a coated polycarbonate automotive window. However, the results did not represent the performance of the product in actual service very well. Atomic force microscopy was used to examine the abraded surfaces after the Taber test and carry out a statistical analysis to explain the observed haze development (the haze after abrasion less the haze before abrasion). It was found that the Taber test data in evaluation of the layered material had a larger standard of deviation than glass due to the occasional occurrence of delamination and chipping at the surface. In addition, its crossed-scratch abrasion pattern might not be a good simulation of the real abrasion experience of the automotive windows.     

浸渍管在高钛型钒钛磁铁矿冶炼中长寿化研究

针对攀钢冶炼高钛型钒钛磁铁矿时浸渍管频繁出现掉料、衬砖剥落、穿孔和断裂等问题，研究优化了振动方式、升温曲线、锚固件和砖型等，衬砖平均侵蚀深度由41．67mm减至13．78mm，蚀损率由2．53％降至1．24％，浸渍管使用寿命由40次／套提升至80．17次／套，减少了更换频次，提高了精炼效率。     

一株具有纤维蛋白溶解活性的海单胞菌的分离和鉴定

目的对从双齿围沙蚕消化道内分离的菌株Y5进行纤维蛋白溶解活性检测及系统分类鉴定。方法用纤维蛋白平板法检测Y5的纤维蛋白溶解活性,并从形态、生理、生化、DNA(G+C)含量、脂肪酸成分、16S rRNA基因序列及系统发生分析等方面进行分类鉴定。结果菌株Y5为革兰阴性杆菌;DNA(G+C)含量为47.5%;主要脂肪酸成分为C_(18:1)ω7c,C_(16:1)ω7c,C_(16:0),C_(10:0)3-OH;16S rRNA基因序列与9种已确定的海单胞菌一致性为93%～97%;在系统发生树中与其他海单胞菌位于同一类群中;该菌株在纤维蛋白平板上显示出明显的纤维蛋白溶解活性。结论菌株Y5属于海单胞菌属。该菌株具有纤维蛋白溶解活性,有望为开发溶栓药物提供又一重要资源。     

微波暗室运动平台系统硬件设计分析

论述了电子战模拟仿真中动目标平台系统的研制过程,提出了一个全新的微波暗室运动平台和测控系统的设计方案,该方案能实现对动目标的实时位置、速度进行标定,能模拟辐射源的三维运动。详细讨论了硬件设计中的特点,并对建设电磁环境实验室动目标的模拟测试跟踪提供了一种先进和实用的手段。     

Scratch resistance of automobile clearcoats: Chemistry and characterization on the micro-and nanoscale

The scratch resistance of polymeric clearcoats intended for automobile exterior surfaces was tested with scanning 3D nanoindentation and laboratory car wash simulation (AMTEC). It could be shown by using “real world” samples with comparable scratch resistance that the applied methods were suitable for discriminating even small differences in scratch resistance with high accuracy. In the area of physical characterization of scratch resistance, the results of this investigation demonstrate the ability of microscopic, single-contact testing methods to reproduce the macroscopically experienced results. By using a combination of different scratch methods, insight into the fundamentals, e.g., chemistry, that are responsible for good or bad scratch resistance, is achieved. One key for this goal is the imaging and analytical evaluation of the damage pattern after the indent, which leads to additional results and models presented in this article. It was found that an essential key to obtaining scratch resistant surfaces is a strengthening of rubber-like elasticity as well as minimizing interactions between individual polymeric chains.     

某钢筋混凝土拱桥无损检测与荷载试验

该桥为一座已使用20余年的钢筋混凝土拱桥。为了全面了解该桥现有状况，对该桥进行了无损检测与荷载试验，以期评估现有桥梁状况，判断桥梁的承载能力。通过检测和试验，为该桥是否能够进行扩宽以适应道路扩建的需要提供了依据，同时可供该类现有桥梁的维护使用和加固改造工作借鉴。     

基于用户能效的电力市场交易仿真

市场是配置资源最有效的方式,建立高效率的电力市场是目前电改的重要组成部分。与此同时,节能减排已成为全球性热点,如何在电力市场体制中考虑能效因素,从而提高社会整体的能效水平,将是未来电力市场研究的焦点。提出了一种基于能效的电力市场交易机制,将用户能效作为调节用户基础电量的重要参数,有助于提高社会整体的能效水平。同时,建立了一种考虑发电侧和用户侧策略的电力市场交易模型,基于Matlab软件平台编写了仿真程序,对不同情形下的电力市场交易情况进行了仿真。仿真结果表明,均值出清的定价方式适用于供求关系变化较大的市场环境,而统一出清方式更适用于供求关系相对稳定的市场环境。     

广东日前电力市场方案设计与市场仿真

回顾了广东省电力直接交易进展情况,参考国外成熟日前电力市场模式,提出了日前市场建设的基本原则,结合广东省电力体制实际情况,设计了全电量竞争的日前市场模式,从交易标的、市场主体、交易时序、交易组织流程、报价机制、交易出清机制、交易执行、交易结算等方面开展了制度设计,并依据广东电网实际数据,对日前电力市场进行了仿真,对仿真结果进行了分析和讨论。