低成本纳米复合材料70％ CeO2·30％ NiO的合成及其催化性能的研究

分别选用水热,浸渍,柠檬酸络合燃烧,共沉淀方法合成了多种前驱体,再经过600 ℃煅烧处理4h,成功合成出纳米复合材料70％ CeO2·30％ NiO,对这些复合材料进行系统的XRD、BET、H2-TPR、O2-TPD表征和CO催化氧化性能测试.     

关于幂等矩阵的组合的几个秩等式及其应用

研究了幂等矩阵的组合a(PQ)k +b(QP)k -cP(QP)k和a(PQP)k +b(QPQ)k -c(PQ)k+1的秩(其中a≠0,b≠0,P是幂等矩阵,Q是幂等矩阵或任意矩阵).用两种方法证明了这些组合的几个秩等式,推广了Tian和Styan的有关结果.作为应用,用这些秩等式给出了(PQ)k±(QP)k和(PQ...     

基于自然特征的增强现实注册算法

增强现实标志点注册算法需在场景中叠加各种标志,系统构造复杂.文中在深入研究机器人视觉伺服系统的基础上,提出了利用虚拟视觉伺服技术、基于自然特征的增强现实注册算法.利用特征点和图像矩作为图像特征,推导出了图像特征变化量与虚拟摄像机相对位姿变化量之间的关系矩阵(即图像的雅可比矩阵),实现了基于自然特征的三维注册算法.与混合跟踪注册算法、共面四点注册算法相比,文中方法具有更高的精度.     

变采样周期PI控制算法的仿真研究

使用ＭＡＴＬＡＢ中的ＳＩＭＵＬＩＮＫ仿真工具对变采样周期的全数字化直流调速系统的ＰＩ控制算法进行了仿真研究,并提出了变采样周期的ＰＩ控制新算法,应用此算法设计的直流调速系统具有良好的性能     

Effects of mechanical strain amplitude on the isothermal fatigue behavior of H13

Isothermal fatigue (IF) tests were performed on H13 tool steel subjected to three different mechanical strain amplitudes at a constant temperature to determine the effects of mechanical strain amplitude on the microstructure of the steel samples. The samples' extent of damage after IF tests was compared by observation of their cracks and calculation of their damage parameters. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to observe the microstructure of the samples. Cracks were observed to initiate at the surface because the strains and stresses there were the largest during thermal cycling. Mechanical strain accelerated the damage and softening of the steel. A larger mechanical strain caused greater deformation of the steel, which made the precipitated carbides easier to gather and grow along the deformation direction, possibly resulting in softening of the material or the initiation of cracks.     

工业现场LED数据显示屏系统的开发

分析工业现场LED数据显示屏主要是将各种类型传感器采集的数据，提出利用数据采集转换芯片，或者利用接口传送到LED显示屏上，进行数据的实时显示方案。     

存款准备金率变动对股市影响的实证研究

运用VAR模型的G ranger因果检验和脉冲响应函数分析研究了中央银行存款准备金率变动对沪深300指数的影响,并通过方差分解分析前者对后者的贡献度。得出的结论是存款准备金率变动对股市波动在短期内存在一定负方向的影响,股市波动对存款准备金率则无影响。但在长期内,存款准备金率变动对股市影响很小。最后在此基础上提出相关的货币政策的建议。     

Biomimetic fluorapatite films for conservation of historic calcareous stones

Fluorapatite protective films were prepared on marble substrates using a biomimetic method. By mimicking the mineralization mechanism of enamel, phosphorus and fluorine were introduced on the surface of the marble substrate. In the presence of a biological template, namely collagen, an integrated fluorapatite film was produced and the marble substrate was entirely covered. The prepared fluorapatite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) spectroscopy. The performances of the fluorapatite films were evaluated by color changes, capillary water absorption, and acid resistance tests. The results revealed that the fluorapatite films had good compatibility with the marble substrate; the physical properties such as color and capillary water adsorption of the marble substrates were unchanged. The fluorapatite films also had good acid resistance and were stable even in heavy acid rain.     

伸缩臂叉装车变幅机构的铰点位置优化

鉴于伸缩臂叉装车变幅机构的铰点位置的确定直接影响变幅液压缸的负载值和压力冲击,分析了变幅机构的工作特性,以提高传动力比和降低油压波动值为目标,采用统一目标函数法建立多目标优化设计数学模型,利用Matlab遗传算法工具箱对变幅机构的铰点位置进行优化.结果表明优化后的尺寸能大大提高叉装车的变幅机构的作业性能.     

新时期煤炭企业矿山管理新思路浅析

结合当前国内煤炭市场形势及国家煤炭企业综改政策，对新时期煤炭企业矿山管理的安全管理和经营管理等方面提出了创新性思考和可行性建议。