Experimental Evaluation of Thermal Properties of Grouting Materials

This study is aimed at the thermal analysis of sealant mortar （usually a mixtures of bentonite and cemem with addition of sand） used in geothermal cooling and heating. In particular, thermal conductivity and diffusivity measurements were performed on differem sealant mixtures by using Hot Disk thermal constants analyzer in order to identify the interesting thermal properties of grouting materials. The grouting materials that we considered are of porous nature and, if used in the presence of groundwater, have different levels of imbibitions. It is important to know the thermal behavior of these materials at different water content. A first set of measurements was performed on a not-tinted material at room temperature; then the samples were led to saturation conditions by contact capillary imbibitions with a cotton wool layer moistened in water. The determination of thermal conductivity in these test conditions appears to be critical compared to the measuremems on non-timed sample. The thermal conductivity tests have revealed how the thermal behavior of the samples analyzed is essentially determined by the density and water content of the material： in fact, the thermal conductivity increases of two to three times the value of the not-tinted material.     

PVD涂层硬质合金钻头钻削SKD61模具钢试验的研究

涂层技术在切削刀具中得到越来越广泛的应用,性能优异的涂层可以显著改善刀具表面性能,提高其高温硬度、隔热性能、热稳定性及冲击韧性,从而可大幅度提高刀具的切削速度和寿命。基于常见的钻削加工方式以及难加工材料SKD61模具钢,采用应用广泛的刀具涂层工艺PVD(物理气相沉积)涂层,进行了系统的切削试验。分别从切削力、加工表面质量、切屑变形机理等方面,对不同涂层刀具的切削性能做出了对比分析和基于试验结果的合理判断。     

粉末冶金盘式汽车摩擦片热压成形的数值模拟与实验研究

为了探明汽车盘式摩擦片剪切强度不稳定的原因,用数值方法模拟摩擦片热压成形过程中温度分布和模具局部失效对粉末流动和固结的影响,并进行了相应的实验分析和验证.结果表明:模具局部失效及温度梯度分布造成基体材料溢出,基体材料的流动导致在剪切面上纤维集合定向排列,从而大幅度降低试样的剪切强度;当基体出现剪切层,导致纤维成定向分布时,剪切强度明显下降,低于要求的0.4 MPa(最高值仅为0.356 MPa),而在无溢出情况下,剪切强度都高于0.4 MPa.     

中俄管道顺序输送技术标准差异分析

评价了国内外成品油管道技术现状和发展趋势。基于中亚、中俄跨国管道迅速发展,国内已开展中国和俄罗斯标准差异研究,但在成品油管道运行领域较少涉及,为此选取了俄罗斯有代表性的成品油管道综合性标准。该标准的先进性主要体现在以下几个方面:油品排列原则更为细化、采用工艺混油缓冲塞和限定控制初始工艺混油以减少混油、规定成品油管道最低允许流速、严格控制混油切割浓度、基于定量计算掺混比例进行混油掺混作业等。最后,针对完善我国成品油管道运行标准提出了建议。     

一种新的3容错扩展RAID码

随着存储系统规模的扩大,如何提高存储系统可靠性成为一个必须解决的问题. 目前的双容错独立冗余磁盘阵列(RAID)码已经无法满足存储系统可靠性要求. 在双容错行对角奇偶校验(RDP)码的基础上,提出了一种编码冗余率和纠错能力达到编码最优的新的扩展RDP-RAID码,可以允许任意3磁盘同时故障,并给出了一种基于二元矩阵变换的简单和直观的译码算法. 与STAT码和EEOD码相比,扩展RDP-RAID码的编译码复杂度、更新复杂度、存储效率的综合性能可达到最优,存储可靠性高.     

硬盘还原保护技术分析与实现

基于笔者自行研发的硬盘还原软件,对硬盘还原技术原理进行了深入浅出的分析研究.同时,针对Win9x、Windows2000/XP内核技术的特点,简明扼要地介绍了VSD和WDM技术在硬盘还原保护软件中的应用.     

CMD 圆盘型弹性微孔膜曝气器的研究

通过在对现有曝气器装置分析的基础上，研究开发的ＣＭＤ圆盘型弹性微孔膜曝气器，具有氧转移效率高、经济、节能等特点，并具有广阔的发展前景和实际意义。     

光盘基片精密注射成型技术

针对光盘基片高精度、高质量要求，从原料、成型方法、成型机理、注塑机、模具等方面，探讨了光盘基片的精密注射成型技术。     

高能量密度脉冲等离子枪在硬质合金刀具上沉积高硬耐磨涂层研究

用高能量密度脉冲等离子体枪，于室温下在硬质合金刀具基体上分别成功沉积了硬度高、耐磨损、膜基结合力强的TiN、TiCN和TiAlN薄膜。在优化的工艺条件下，所得TiN、TiCN、TiAlN薄膜纳米硬度分别可达27GPa、50GPa和38GPa；杨氏模量分别可达450GPa、550GPa、650GPa。纳米划痕实验临界载荷分别达90mN、110mN和100mN以上。切削实验表明，涂层刀具可用于高速切削，刀具后面磨损明显减小。刀具力学性能的改善归因于更优异力学性能涂层的沉积、良好的膜基结合力以及涂层特殊的显微结构。     

Temperature measurement performance of thin-film thermocouple cutting tool in turning titanium alloy

The measurement of cutting temperature is one of the most important research topics in the field of cutting. Traditional technology for cutting temperature measurement has limitations because it cannot accurately measure the real transient temperature change in the cutting area. In this study, a thin-film thermocouple sensor with high temperature measurement accuracy and rapid response was positioned near the cutting tool tip to prepare a thin-film thermocouple temperature-measurement tool. Its Seebeck coefficient was 48.13 μV/°C, and the highest temperature difference measured between cold and heat regions was 600 °C. The cutting temperature of a TC4 titanium alloy was measured using an infrared thermal imager and the proposed thin-film thermocouple temperature measurement tool in an orthogonal turning test. The test results were analysed to verify the reliability, accuracy, and repeatability of cutting temperature measurements. The cutting length could extend beyond 1500 m.