In Situ Formation of a Novel Nanocomposite Structure Based on MCM-41 and Polyethylene

M41S materials are prepared by in situ assembly of inorganic precursors and organic template and can be viewed as nanocomposites of the siliceous phase and organic surfactant. Calcination of these precursors gives the M41S materials that have been used to prepare novel nanocomposite structures, in which the organic phase inside the nano-sized pores is isolated by the nano-sized inorganic pore walls. The nanocomposite structures can be formed by in situ polymerization of monomers inside the channels. Polymerization of ethylene takes place inside the nano-sized pores, producing the desired nanocomposite structure. The resulting polyethylene was found to be a mixture of crystalline and amorphous phases.     

A simple method for measuring the cell gap of a reflective twisted nematic LCD

A simple method is demonstrated for measuring the cell gap of reflective twisted nematic (RTN) liquid crystal (LC) cells. This method utilizes a single laser beam and crossed polarizer configuration such that Fabry-Perot effect and surface reflection are eliminated. Experimental results agree well with theory.     

镀镍云母导电复合材料的研究

对云母粒子化学镀镍及以LDPE为基材,镀镍云母粒子为填料制备的导电复合材料进行研究。认为此种导电复合材料只有质量轻、强度大及良好的导电等性能。     

浅谈实验室检验在科研生产中的作用

文章阐述了实验窀检验在科研生产中的作用及发挥作用的巨大潜力。     

HfOxNy的场发射特性

用直流溅射和高温退火相结合的方法制备了HfOxNy薄膜并测试了其场发射性能,发现其具有较低的开启电场、较大的发射电流密度以及很好的发射稳定性.高压"锻炼"对提高HfOxNy场发射性能起着关键作用,这与高压"锻炼"下薄膜内部结构和表面性质的改变有关.对场发射机理的研究表明,HfOxNy的场发射符合经典的FN隧穿理论.     

Development of a heterogeneous microstructurally based finite element model for the prediction of forming limit diagram for sheet material

A heterogeneous finite element model with randomly distributed inhomogeneities has been developed for the determination of the forming limit diagram (FLD) for thin aluminum sheet material based on the prediction of localized necking. The strength difference between the inhomogeneities and the matrix is ascertained either from the fluctuation of the experimental stress-strain curve or from a micromechanical analysis that uses a representative particle field. By changing the specimen geometry and friction conditions, different stress states (or strain paths) are achieved. A plot of the critical Oyane fracture parameter is used to identify the limit strain state. Also, a plot of equivalent plastic strain rate is used to distinguish the boundary of intense shear bands and hence to identify where to take the measurement point. Both a plane stress model and a three-dimensional (3-D) model are adopted to predict the shear banding phenomenon and hence the FLD. The predicted FLD agrees well with the measurements from a recent round robin experimental FLD involving several independent research laboratories. The Taguchi method is applied to assess how the various parameters involved in the heterogeneous model affect the calculated forming limit strain.     

化学教学中"多媒体教学课件开发"基本思路的探讨

在电化教学的基础上，现代教育技术在教学领域里起着越来越重要的作用，而多媒体教学课件。则是现代教育技术领域内的一技奇芭，正逐渐地放射出强大的、耀眼的光辉。本文将从四个方面探讨化学教学中“多媒体教学课件开发”的基本思路。     

A 5 mW and 5% efficiency 210 GHz InP-based heterostructure barrier varactor quintupler

This letter reviews the design, construction, and measurement of a 210 GHz heterostructure barrier varactor frequency quintupler. The quintupler utilizes planar heterostructure barrier varactors (HBVs) based on the InGaAs/InAlAs/AlAs material system and has produced a measured output power of 5.2 mW with 5.2% conversion efficiency at 210 GHz. This performance is comparable to the state-of-the-art results reported in the literature for HBV frequency triplers operating at millimeter and submillimeter wavelengths.     

丙烯酸酯与甲基丙烯酸酯的共聚及性能研究

采用悬浮聚合法，以丙烯酸－２－乙基－己酯与甲基丙烯酸十二酯为单体，合成了共聚型高吸油性树脂。研究了共聚单体的配比、交联剂用量、引发剂用量诸因素对高吸油性树脂的性能影响。制得的树脂可以吸其自身质量的１１．８倍的煤油、１４．７倍的苯、６．５倍的泵油。     

钢管机械扩径工艺研究

介绍了大口径直缝焊管机械扩径的优点，原理及扩径力的计算，找出影响扩径力及扩径头寿命的因素。