典型ATM交换结构分析与交换机设计分类

目前的通信网正逐步向宽带化、综合化和智能化方向发展,为了传送高清晰度电视(HDTV)图像及高速数据,要求通信网高速宽带化。高速宽带通信与现有的电话及数据通信相比,应具有极宽的通信频带(几十Mbps以上)。另一方面,随着科技的发展,人们对通信的需求不断增加,导致未来通信业务的不确定性。因此,人们致力于研究新的通信方式以适应上述情况,其中,ATM可能是实现宽带ISDN的最佳方式,可以满     

三维编织复合材料预制件表面图象计算机分析系统

介绍了三维编织复合材料预制件表面图像检测与纹理分析的 基本原理。该系统以CCD为传感器,与微型计算机连接,进行三维编织复合材料预制件表面 编织角的检测。本系统对改善三维编织复合材料预制件的加工工艺具有指导作用,同时也为 纺织复合材料新的性能指标建立提供了有利条件,为纺织复合材料在各个领域的广泛应用提 供理论基础。     

预辐射聚丙烯纤维接枝N-异丙基丙烯酰胺及其对Fe(II)离子的吸附

采用预辐射接枝法,将N?异丙基丙烯酰胺(N-Isopropylacryamide,NIPAAm)接枝于聚丙烯纤维。研究了不同条件下接枝纤维对亚铁离子的吸附和解吸附情况。结果表明,在较低温度(5℃)及pH≈0条件下,接枝纤维对金属离子(Fe2 )具有良好的吸附性能;而在较高温度(50℃)下pH≈3时,被吸附的Fe2 几乎能被较完全解脱下来。     

Micromechanical constitutive modelling of granular media: Evolution and loss of contact in particle clusters

Micromechanical constitutive equations are developed which allow for the broad range of interparticle interactions observed in a real deforming granular assembly: microslip contact, gross slip contact, loss of contact and an evolution in these modes of contact as the deformation proceeds. This was accomplished through a synergetic use of contact laws, which account for interparticle resistance to both sliding and rolling, together withstrain-dependent anisotropies in contacts and the normal contact force. By applying the constitutive model to the bi-axial test it is demonstrated that the model can correctly predict the evolution of various anisotropies as well as the formation of a distinct shear band. Moreover, the predicted shear-band properties (e.g. thickness, prolonged localisation, void ratio) are an even better fit with experimental observations than were previously found by use of previously developed micromechanical models.     

Quattor: Tools and Techniques for the Configuration,Installation and Management of Large-Scale Grid Computing Fabrics

This paper describes the quattor tool suite, a new system for the installation, configuration, and management of operating systems and application software for computing fabrics. At present Unix derivatives such as Linux and Solaris are supported. Quattor is a powerful, portable and modular open source solution that has been shown to scale to thousands of computing nodes and offers a significant reduction in management costs for large computing fabrics. The quattor tool suite includes innovations compared to existing solutions which make it very useful for computing fabrics integrated into grid environments. Evaluations of the tool suite in current large scale computing environments are presented.     

Compaction of thick carbon/phenolic fabric composites with autoclave method

Carbon/phenolic composites are used in the nozzle parts of solid rocket motors due to their heat-resisting, ablative, and high strength characteristics, which are required to endure the high temperature and pressure of combustion gas passing through the nozzle. But the thick axi-symmetric structure of the composite nozzle induces high thermal residual stresses due to the large difference of coefficient of thermal expansion (CTE) between the in-plane and the out-of-plane. In this work, in order to reduce the through-thickness CTE and the void content, a compression in the thickness direction was applied to the composite prepreg by a compressive jig during manufacturing of composite to supplement the low autoclave pressure. The through-thickness CTE of the fabric composite was calculated by a compaction model and compared with the measured one by thermo-mechanical analysis. The through-thickness CTE changed drastically with respect to the compaction amount, and the void content of the carbon/phenolic fabric composite laminate showed different characteristics from the ordinary fabric laminates with respect to the autoclave pressure and the jig pressure.     

聚丙烯酸类共聚物/SiO2硅织物有机-无机杂化材料的合成与表征

以γ缩水甘油氧丙基三甲氧基硅烷为偶联剂,通过溶胶-凝胶法制备了聚丙烯酸类共聚乳液/SiO2硅织物的有机-无机杂化材料,利用FT-IR、SEM、DSC及TG等手段对其进行了结构表征.SEM照片显示有机组分与无机组分间分布较均匀,并出现了相互贯穿;DSC表明Tg为206℃;对比法测得的比表面为81.61m2/g.实验结果证实该硅织物杂化材料中存在-Si-O-C-共价键,热稳定性较好.     

非晶态Ni-Fe-P合金屏蔽织物的工艺优化及耐蚀性研究

通过在已化学镀铜涤纶织物上电沉积非晶态Ni-Fe-P合金,制备出一种镀层致密均匀的柔性金属化屏蔽织物。研究和分析了电流密度、温度和p H值对合金织物方阻值、增重率及屏蔽效能的影响,从而制定出最佳工艺。通过对比腐蚀前后非晶态Ni-Fe-P合金和非晶态Ni-P合金镀层表面形貌、成分和电磁屏蔽效能可以得出,在电流密度为8.7 A/dm2,温度为60℃,p H值=1.5的工艺条件下所制备的非晶态NiFe-P合金织物结晶更加细化、光亮,致密性和均质性都得以明显提高,并具有良好的耐腐蚀性能,且在300 k Hz~1.5 GHz频率范围内的电磁屏蔽效能达到了69.20~80.30 d B。     

现代建筑用PVC膜结构复合材料工艺研究

介绍现代建筑用PVC膜结构复合材料的性能特点。结合PVC膜结构复合材料的工程状况,分析涂层工艺方法对产品质量的影响,提出一种新的工艺方法制作高性能PVC膜材,并展望PVC膜结构复合材料广阔的应用前景。     

一种基于StarFabric总线的通用信号处理平台设计

基于共享总线(CPCI或VME)的信号处理模块由于共享总线带宽逐渐成为提升信号处理系统性能的瓶颈,开关互连技术是新一代信号处理系统互连的趋势。给出了一种基于StarFabric总线的多DSP构成的通用信号处理平台设计,突破了这种设计瓶颈,能满足多种信号处理功能的需要。