硫化橡胶压缩应力松弛试验及对制品密封效果的探讨

应用ＡＧ５００Ａ型电子拉力机对硫化橡胶在不同速度、温度下的压缩过程及压缩恒定后的应力变化进行了试验。该结果应用于橡胶油封研制中，取得很好的效果。同时对压缩应力应化对密封效果进行了讨论。     

Effects of diacrylate monomers on the mechanical properties of polymer concrete made with wet aggregates

Because normal polymer concrete does not work well with wet aggregates, diacrylate (DA) monomers were evaluated for improving the mechanical properties of polymer concrete made with wet aggregates. Zinc diacrylate (ZDA) and calcium diacrylate (CDA) were each used as an additive to resins (two epoxies). The variables were the amount of diacrylate monomers and the aggregate conditions (wet or dry). Compressive strength, flexural strength, workability, working time, and curing time were measured. ZDA was found to improve the workability and the working time, and CDA was found to improve the compressive and the flexural strength. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1077–1085, 2004     

Structural material from waste plastic

In efforts to contribute to community development, particularly in the context of Egyptian communities, waste plastics materials were successfully recycled without the difficult task of separation and reused to economically produce new structural material. Recycling was performed by mixing molten waste plastics with sand to produce these new materials. Samples with different percentages of plastics and different particle sizes of sand were used in the process. Materials showed acceptable density and high compressive strength, which was shown to be at a maximum with contents of about 30–40% waste plastic. Furthermore, certain types of sand having different colors were used to produce attractive materials, suitable for decorative uses. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2543–2547, 2004     

Modification of sandy soil using water‐borne polymer

A new polymeric system has been applied for structural modification of (noncompactable) sandy soils. The system is based on a water‐borne styrene acrylic polymeric formulation (emulsion) containing varying amounts of solid polymer. The present work deals with system optimization and measurements designed to examine the effects of polymer content on hydraulic conductivity and compressive strength. Samples were prepared from prescribed amounts of polymer, water, and sand by using two different preparations methods (mixing and spraying). Measurements of hydraulic conductivity for both sets of samples were conducted in a flexible membrane test apparatus. For the first set of samples, the permeability coefficient of the sand was noted to be reduced 10‐fold (from 10^?5 to 10^?6 m s^?1) upon the incorporation of about 2% polymer. In the second set (samples prepared with the spraying method), the hydraulic conductivity was further reduced to 7.2 × 10^?7 at a polymer concentration of about 2%. Stress–strain measurements made on dry cylindrical specimens disclosed remarkable enhancement in the mechanical behavior of the system. For both types of preparation methods, the compressive strength and modulus of elasticity increased linearly with the polymer concentration in the sample. Scanning electron microscopic examination revealed that the dramatic reduction in the permeability and the improved mechanical properties are attributed to the polymer coverage of the sand particles and the development of interconnecting ties between them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2484–2491, 2003     

几种合成橡胶的共混、硫化特性与性能的研究

研究了PUR／CR，CSM／NBR，EPDM／IIR几种合成橡胶的共混和硫化特性，以及共混比对共混胶力学性能、耐热老化性能、耐油性能、压缩永久变形和动态力学性能的影响。     

基于前向预测并行追踪的视频压缩传感方法

为了减小视频信号采集端的负担,提出一种基于压缩传感理论的视频压缩算法模型。该模型采用广义轮换矩阵获取视频帧的测量值,再结合视频压缩的运动补偿预测关键技术,消除视频帧间冗余。然后在并行贪婪追踪算法中引入前向预测技术作为重构算法,最终获取重构的压缩图像。实验对比了在不同算法下的重构图像和不同采样比下不同算法的重构PSNR值,然后利用所提方法得到视频序列的重构压缩图像。实验结果表明,该算法模型能较精确地获取压缩的视频图像,适合在视频压缩中应用。     

低熵图像序列无损压缩

大规模的云渲染技术带来了大量的三维图形渲染数据。为了减小集群渲染产生的图像序列数据的传输以及存储代价,针对渲染图像序列低熵的特点,基于字典编码技术提出了降低数据局部复杂性的无损数据压缩方案。该方案通过数据重排技术来大大提高数据的局部冗余度,从而提高数据无损压缩效率。为了进一步解决大规模图像序列的压缩耗时问题,提出了一种云计算平台上的分布式图像压缩处理方案,充分利用现有云计算中Map/Reduce计算模型实现了分布式编码方案。实验结果证明,对于渲染产生的大规模低熵图像序列,提出的方案能够有效提高编码率并减少编码时间。     

Behavior of high strength concrete with and without steel fiber reinforcement in triaxial compression

Based on an extensive experimental program, this paper studies the behavior of high strength concrete and steel fiber reinforced high strength concrete under uniaxial and triaxial compression. Triaxial stress-strain relations and failure criteria are used to evaluate the effect of steel fiber reinforcement on the mechanical properties of high strength concrete in triaxial compression, which is found to be insignificant.     

基于“北斗”通信的文本数据传输

北斗卫星导航系统是我国自主研发且具有通信能力的区域性卫星导航系统,根据“北斗”覆盖面广、安全性好的特点,可对我军情报数据,装备数据等文本信息进行远距离可靠传输。针对“北斗”传输带宽小的特点,采用 Huffman数据压缩技术对文本数据进行无损压缩,可以提高通讯效率。论文主要介绍了 Huffman数据压缩技术原理在“北斗”数据通讯中的应用及文本数据面向窄带条件下的分发组织模型。     

基于改进零树编码的ROI图像联合压缩加密算法

提出了一种能灵活控制感兴趣区域（Region Of Interest, R0I）的重建质量且将图像的压缩与加密同步实现的编码算法。该算法将图像进行ROI划分后利用加权因子灵活控制其编码量,再通过结合改进零数的压缩算法与算术编码,使用密钥对压缩产生的原始上下文与原始判决进行修正,从而实现ROI的联合压缩加密。实验结果表明,当密钥正确时, ROI的重建质量随着加权因子的变化而变化;当密钥出错时, ROI重建质量急剧下降,图像实现分区域加密,从而验证了本文所提出算法的可行性。