高性能双向拉伸聚丙烯(BOPP)薄膜的研究

采用自主开发的BOPP薄膜专用多功能改性母料,研制生产了香烟包装用高性能BOPP薄膜,从薄膜的厚度均匀性、力学性能、热收缩性能、摩擦性能、光学性能以及使用特性方面进行了分析,结果表明新开发的BOPP薄膜的各项性能指标均有较大的改进,特别具有较高的热收缩率、较低的摩擦系数和较好的光学性能,在烟厂的批量使用证明了该产品的质量控制指标和使用性能的稳定性.     

本安型锚杆锚固质量导波无损检测仪的开发

设计开发了一种基于导波的便携式本安型锚杆锚固质量无损检测仪.介绍了该检测仪设计开发的过程,包括检测仪的硬件设计、软件设计和上位机软件的设计开发.制作锚杆模型进行实验,使用检测仪对锚杆进行检测,检测仪能够准确地检测出锚杆的有效锚固长度和锚固力,判断出锚杆的锚固质量.通过重复性试验证明,检测仪性能稳定可靠.检测仪满足本质安全型防爆要求,能够在煤矿井下安全使用,在煤矿井下的锚杆锚固质量检测上具有一定的应用潜力.     

基于硅基回热器的微型脉管制冷机的数值模拟

随着电子器件热流密度的不断增加,开发和使用结构紧凑且高效的微型制冷器件已非常迫切.使用Fluent 19.0软件对基于硅基回热器的微型脉管制冷机在不同回热器空隙率、冷热端温度和相位条件下的制冷性能进行了数值计算.结果表明:硅基回热器的空隙率对制冷性能有重要影响;在固定几何参数下,存在一个最佳空隙率使得制冷机的COP最大...     

基于VB.NET的图书管理系统的开发设计

介绍使用VB .NET和SQL Server 2000开发图书管理系统的方法,该系统具有功能强大、安全性好、通用性能好、扩充性好以及易于操作等优点。     

二级煤矿许用粉状乳化炸药研究及应用

文章从我国民爆器材发展总体规划出发,分析了国内外煤矿许用炸药的发展现状,介绍了新近开发的二级煤矿许用粉状乳化炸药.文中阐述了这种新型煤矿许用炸药的配方、生产工艺及其性能特点,并对其在地下瓦斯矿井的应用情况进行了总结和分析.检测及应用表明,这种新型工业炸药具有良好的爆炸性能、储存性能和安全性能.井下爆破试验结果表明,煤掘爆破中炮孔利用率在97%以上,炸药单耗比原使用的乳化炸药降低23%.     

日开发出高性能液晶性有机半导体

据媒体报道,日本研究人员开发出了电子传递能力强、加工成形性能好的液晶性有机半导体。在有机半导体中,为了提高产品性能,必须增强半导体的电子传递能力,一般使用     

石墨系簿膜的形成及应用

一、引言随着先进技术的开发,对在这些技术中所使用的炭材料要求有更高的功能和高性能。为此作为解决的对策提出了:1.开发新的炭材料制造技术;2.引入其它领域的制造技术;3.和各种技术复合化等。通过这些措施制得了具有种种特性的炭材料。将低沸点有机物在气相炭化,即所谓CVD法便是这类制造技术之一。     

国产PVDC树脂的性能及应用

介绍了国产PVDC树脂的开发历程和生产工艺,对国产PVDC树脂的,详细叙述了国产PVDC树脂在颗粒结构和分布、结晶、熔融、降解、稳定性方面的特性,比较了国产树脂和国外同类产品在加工性能上的差异,指出国产树脂具有优良的性价比,值得大力推广使用.     

Vb访问数据库的方法比较

Visual Basic是一门开发Windows应用程序很好的一种语言,使用它能够开发出大型的应用系统.它具有访问各种数据库的功能.用Visual Basic访问数据库有许多可供选择的方案,但是选择那种方案更能使开发队伍和应用软件在当前处于有利位置并且适应将来的发展方向呢?这些解决方案各有什么特点?介绍几种Visual Basic访问数据库的方法,对这些数据接口的性能进行了比较,并提出相互的转化关系.     

基于Allegro3515霍尔传感器的位标器主镜磁钢性能测试系统

针对目前国内对主镜磁钢测试靠人工操作存在测量误差大,工作效率低的现状,研制了一套基于Allegro3515霍尔传感器的位标器主镜磁钢性能测试系统,用以测试主镜磁钢的主要性能技术指标.并且使用Visual C 6.0自主开发了相应的测试系统控制软件,实现了自动化、智能化的高精度高效率测试.论文详细分析了该测试系统的工作原理及测试方法.     

Kohlenstoff-Fäden und deren Verwendung in Verbundwerkstoffen

Carbon fibres and carbon fibre composite materials. Carbon fibres are a new reinforcement for high performance composite materials. Their most interesting property is the high Young's modulus. The tensile strength of carbon fibres exceeds 200 kp/mm², the Young's modulus 50,000 kp/mm². Carbon fibre reinforced plastics are mainly used where high stiffness is needed. In most cases, carbon fibre composite components are manufactured by filament winding burt also by lamination and moulding. Data about the different processes for the production of carbon fibres as well as mechanical properties are given. In addition to the different manufacturing methods of composite materials a survey about the today applications is given.     

Ultrasonic Study of Elastic Anisotropy of Material Composite

The anisotropic elastic properties of two Aluminium Matrix Composites (AMC) were characterised using an ultrasonic method. The composite materials, fabricated by squeeze casting included aluminium matrix reinforced by alumina fibre and carbon fibre, respectively. The elastic constants were determined using an optimisation method associated to a classical ultrasonic immersion device. The methodology to recover the elastic constants consists in minimising the square deviation between calculated velocities and the experimental ones, measured under variable incidence from a computer controlled ultrasonic immersion device. The method of optimisation we use in this work is based on Levenberg–Marquard algorithm allowing a better convergence to the physical solution of the inverse problem. The elastic anisotropy of the two materials is discussed and the results are compared to experimental data taken from tensile tests and to values obtained by two models: the rule of mixture and a simplified Eshelby model.     

A non-destructive X-ray microtomography approach for measuring fibre length in short-fibre composites

An improved method based on X-ray microtomography is developed for estimating fibre length distribution of short-fibre composite materials. In particular, a new method is proposed for correcting the biasing effects caused by the finite sample size as defined by the limited field of view of the tomographic devices. The method is first tested for computer generated fibre data and then applied in analyzing the fibre length distribution in three different types of wood fibre reinforced composite materials. The results were compared with those obtained by an independent method based on manual registration of fibres in images from a light microscope. The method can be applied in quality control and in verifying the effects of processing parameters on the fibre length and on the relevant mechanical properties of short fibre composite materials, e.g. stiffness, strength and fracture toughness.     

Effective simulation of the mechanics of longitudinal tensile failure of unidirectional polymer composites

An efficient computational model to simulate tensile failure of both hybrid and non-hybrid composite materials is proposed. This model is based on the spring element model, which is extended to a random 2D fibre packing. The proposed model is used to study the local stress fields around a broken fibre as well as the failure process in composite materials. The influence of fibre strength distributions and matrix properties on this process is also analysed. A detailed analysis of the fracture process and cluster development is performed and the results are compared with experimental results from the literature.     

生物体系介电性质的复合材料理论模型

生物体系作为一类特殊材料,其电学性质是研究仿生材料设计、电阻抗成像以及电磁场生物效应的发生与防护等问题的基础。目前已有较多复合材料模型被应用于生物体系介电性质问题的研究,但由于生物组织离体后的介电特性会发生较大变化,故已有经典复合材料介电特性模型用于阐释生物体系介电特性还存在一定局限性。从几类典型复合材料理论模型的适用性出发,介绍了生物体系介电特性理论研究进展,总结了理论研究结果与实验测量结果的差异性。分析了复合材料理论模型在生物体系介电性质理论研究中应用的不足并提出了改进的建议,对复合材料理论模型在生物体系电学特性问题研究领域的进一步发展与应用等问题提出了展望。     

Composites in context

The large scale social changes which influence the development of new materials are reviewed and the new materials and processing methods being developed in response to these are described and contrasted with some recent advances in composite materials science.The particular technologies described are injection casting and superplastic forming, high temperature reinforcement by in situ composites and mechanical alloying. Aluminium lithium alloys are compared with carbon fibre reinforced plastics and with SiC reinforced aluminium. The reasons for the interest in new ceramic materials are reviewed and methods used to toughen ceramics are explained. Fibretoughening i is the most effective. Finally the properties of the newest composites containing carbon fibres in thermoplastic matrices are reviewed.     

Potential materials for food packaging from nanoclay/natural fibres filled hybrid composites

The increasing demand for new food packaging materials which satisfy people requirements provided thrust for advancement of nano-materials science. Inherent permeability of polymeric materials to gases and vapours; and poor barrier and mechanical properties of biopolymers have boosted interest in developing new strategies to improve these properties. Research and development in polymeric materials coupled with appropriate filler, matrix-filler interaction and new formulation strategies to develop composites have potential applications in food packaging. Advancement in food packaging materials expected to grow with the advent of cheap, renewable and sustainable materials with enhanced barrier and mechanical properties. Nanoparticles have proportionally larger surface area and significant aspect ratio than their micro-scale counterparts, which promotes the development of mechanical and barrier properties. Nanocomposites are attracting considerable interest in food packaging because of these fascinating features. On the other hand, natural fibres are susceptible to microorganisms and their biodegradability is one of the most promising aspects of their incorporation in polymeric materials. Present review article explain about different categories of nanoclay and natural fibre based composite with particular regard to its applications as packaging materials and also gives an overview of the most recent advances and emerging new aspects of nanotechnology for development of hybrid composites for environmentally compatible food packaging materials.     

Potentiality of utilising natural textile materials for engineering composites applications

This paper gives an overview of utilising natural textile materials as reinforcements for engineering composites applications. The definition and types of textile materials are addressed to provide readers a thoughtful view on the role of these materials in a structural composite system. Available material properties of natural textile and their composites are critically reviewed here. In general, these materials are categorised into fibre, yarn and fabric forms. The load bearing capacity of natural textile fibre reinforced polymer composites is governed by the quantity, alignment and dispersion properties of fibres. It has been found that the natural fibre reinforced composites are limited to use in low to medium load bearing applications. However, a limited research work has been performed to date and there is a significant gap between the high performance textile fabric and their use as reinforcement in fibre reinforced composite materials.     

塑性加工对Csf/Al复合材料组织与性能的影响

短碳纤维增强铝基复合材料可以经塑性变形加工成各种形状的零件。但塑性变形过程对材料的组织与性能有着重要影响。本工作用挤压浸渗法获得的Caf/Al复合材料为毛坯。通过挤压的方法。研究了变形温度、变形量等对材料组织与性能的影响。结果表明，一定量的塑性变形可以弥合浸渗不完全留下的微小空隙，并使纤维成方向性排列，复合材料的性能得到提高。但大变形会使纤维断裂，影响增强效果。变形温度越高，对复合材料性能越有利。     

Composite materials based on wood and nylon fibre

Nylon-wood fibre and polypropylene-wood fibre composite materials were manufactured without any additives to determine the effects of wood fibre on the mechanical properties of the different composites. The raw materials used were eucalypt hardwood fibre, Nylon fibre obtained from stockings, and polypropylene (PP) pellets. A hot press technique was used to manufacture the composite materials, and improvements in the manufacturing methods are suggested. Tests were carried out on the manufactured boards to determine tensile strength and modulus of elasticity. Fracture surfaces were examined using scanning electron microscopy to investigate failure mechanisms. An increase in tensile strength and modulus of elasticity was observed in wood fibre/Nylon matrix composites, indicating that interfacial bonding occurred between these two phases. Bundles of wood fibres with internal voids prevent achieving maximum mechanical properties. The tensile strength of the PP based composites decreased significantly with increasing wood fibre content.