Fuel combustion test in constant volume combustion chamber with built-in adaptor

Combustion tests of pre-mixture of methane and air in constant volume combustion chamber(CVCC) have been carried out by means of flame propagation photo and gas pressure measurement,the effects of CVCC body temperature,intake pressure of pre-mixture of methane and air,equivalence ratio and location of the built-in adaptor have been investigated.The whole combustion chamber can be divided into two parts,i.e.the upper combustion chamber and the lower combustion chamber,by the built-in adaptor with through hol...     

基于主成分分析中的几类问题的计算公式及结论

讨论了主成分分析中的几类问题的计算方法,重点揭示在协方差矩阵中对角元素相同时的第一主成分及贡献率和对角元素不同时的主成分贡献率．经讨论后给出有关计算公式,并说明这些计算公式在多元统计分析中的实际作用     

Effect of fretting amplitudes on fretting wear behavior of steel wires in coal mines

Given that fretting wear causes failure in steel wires, we carried out tangential fretting wear tests of steel wires on a self-made fretting wear test rig under contact loads of 9 and 29 N and fretting amplitudes ranging from 5 to 180 μm. We observed morphologies of fretted steel wire surfaces on an S-3000N scanning electron microscope in order to analyze fretting wear mecha-nisms. The results show that the fretting regime of steel wires transforms from partial slip regime into mixed fretting regime and gross slip regime with an increase in fretting amplitudes under a given contact load. In partial slip regime, the friction coefficient has a relatively low value. Four stages can be defined in mixed fretting and gross slip regimes. The fretting wear of steel wires in-creases obviously with increases in fretting amplitudes. Fretting scars present a typical morphology of annularity, showing slight damage in partial slip regime. However, wear clearly increases in mixed fretting regime where wear mechanism is a combination of plastic deformation, abrasive wear and oxidative wear. In gross slip regime, more severe degradation is present than in the other regimes. The main fretting wear mechanisms of steel wires are abrasive wear, surface fatigue and friction oxidation.     

18世纪晚期市民阶级在德国文化中的自我塑造:《奢侈与时尚期刊》研究

本文通过研究<奢侈与时尚期刊>来分析18世纪德国市民阶级的自我塑造.它宣扬奢侈品消费加速了经济与社会的发展,也为文化进步和国家民族富裕提供了动力.它主要关注私生活里的文化与社会自身的构建,并帮助市民阶级进行自我塑造且与其他阶级进行区分.它还阐述了时尚与奢侈品消费的重要性与必要性,并驳斥了神学与道学将时尚视为虚荣及道德缺陷的偏见.它认为作为文化差异的一部分,服装特色的区分成为一种衡量人民与国家成熟与否的标尺.时尚发挥了视觉艺术的功能,甚至于也是一种行为艺术.此外,时尚还与身体复杂地联系在一起,两者缺一不可.     

生活质量视阈下的大学生“精神贫困”测量指标研究

高校大学生＂精神贫困＂现象已引起人们重视,成为多方关注话题。本文在梳理前人研究成果基础上,对＂精神贫困＂测量指标进行研究,以获得科学的测量指标体系,为获得真实科学的一手资料打进行理论论证。     

Molten salts/ceramic-foam matrix composites by melt infiltration method as energy storage material

A new type of high temperature energy storage material was obtained through the melt infiltration method, using compounding SiC ceramic foam as matrix and Na₂SO₄ as phase change material. The resulting composite material was measured by XRD, SEM, TG-DSC methods. The experimental results indicate that the composite is composed of silicon carbide, sodium sulfate and square quartz, and no chemical reactions occurs between Na₂SO₄ and SiC matrix. Na₂SO₄ has a good bonding with the SiC ceramic foam matrix. As the composite material is characterized by high thermal energy storage density and high thermal conductivity, it is suit for energy storage under high temperature. Funded by the “863” Hi-Tech Research and Development Program of China (2008AA05Z418)     

有限导流垂直裂缝产能及影响因素研究

从渗流理论出发,利用瞬时源、连续源的思想,结合卷积公式、Laphce变换等方法,建立了有限导流垂直裂缝井的产能计算模型,对模型导出的积分方程采用边界元方法(BEM)在Laplace空间进行了求解,利用Stehfest数值反演.获得了实空间的解,从而给出了准确计算有限导流垂直裂缝井产量的方法.此外,还通过定量计算分析了裂缝各设计参数对产量的影响方式和影响程度.通过分析可知,压裂井的日产量随裂缝长度、裂缝渗透率、裂缝宽度的增加而增大,但其产量增加的幅度随三种因素的增大而逐渐减小,因此在实际的油藏水力压裂设计时,应结合压裂成本和增益来考虑合适的设计参数.对压裂井产量预测和水力压裂油藏工程设计具有一定价值.     

超低功耗智能监护报警器研究与设计

该文针对现有国内婴幼儿智能护理产品的优缺点,深入分析了如何防止睡觉受凉和尿床等问题,并对国外婴幼儿护理产品和婴幼儿护理理论进行了深入研究,设计了一种新型的智能化监护报警器。该报警器以低成本的松翰单片机为核心,采用纽扣电池供电,实现了超低功耗设计。实验表明,该装置集尿湿报警、走失报警、踢被报警、发烧报警和人工呼救多功能于一体,在具有使用安全、性能可靠、低功耗、报警及时、准确等优点的同时,还具有极好的性价比。     

基于高速摄像机的电磁电器动态特性测试及其图像处理的研究

为了研究电磁电器动态特性测试的新方法,以智能交流接触器为例拍摄了智能交流接触器的动态过程,对采集的接触器触头、铁心等动态位移图像进行处理,然后应用二进小波多层多尺度分解完成降噪处理,此外本文采用样条求导方式对运动速度进行软测量,从而获得智能交流接触器的真实动态特性,介绍了电磁电器动态特性测试装置与数据处理新方法。该研究采用非接触测试方式,进行图像拍摄与降噪处理,实现了电磁电器动态过程全面、高速与准确的测量,为加快电磁电器产品的研究开发奠定基础。