Modified supercritical CO2 extraction of amine template from hexagonal mesoporous silica (HMS) materials: Effects of template identity and matrix Al/Si molar ratio

In this work, the primary amine template has been extracted from freshly synthesized hexagonal mesoporous silica (HMS) materials by means of modified supercritical carbon dioxide at 60–85 °C under 10.0–20.0 MPa. The influences of amine identity and matrix Al/Si ratio on the extraction efficiencies and structural properties of HMS thus obtained are investigated in detail. The results show that the extraction efficiency is strongly dependent on the pore size of the HMS materials produced by five different templates. For aluminium-incorporated samples, the extraction efficiency is observed to decrease with the Al/Si molar ratio since as the Al/Si molar ratio increases, more amine will get protonated and the matrix/template interactions become stronger, subsequently rendering the extraction more difficult and the efficiency decrease. The formic acid modifier has resulted in better extraction performance than methanol, yielding higher extraction efficiencies. The SFE-treated materials exhibit better structural properties like higher pore volume and specific surface area as compared to those prepared by conventional calcinations. Besides, results of pyridine adsorption and conversion of 2-propanol to propylene suggest that the SFE-treated HMS materials may have higher acidity than the directly calcined samples.     

应用数字散斑相关的运动轴面位置匹配

由于进行转轴动态扭矩测量时的旋转运动会导致应变测量无法直接进行,故提出了应用数字散斑相关技术的动态转轴表面位置匹配方法。该方法可通过对旋转运动中轴面位置的识别实现后续转轴表面应变位移的计算。搭建了运动轴面数字散斑相关实验系统,进行了轴面灰度值稳定转角范围的标定实验、标准转角的转角位移测量实验和运动轴面位置识别实验。实验表明,本系统轴表面图像在-π/15~π/15转角内灰度值较稳定,该转角范围对应转动方向160个像素,相关系数曲面有明显峰值,转角为-π/15和π/15的相关度分别为0.389 2和0.322 1,超出该范围后图像灰度信息淹没在由轴面弧度变化引起的噪声中;标准转角轴面位移识别精度和运动轴面位置识别精度为1像素。本文方法解决了旋转运动轴面的位置匹配这类大位移测量问题,为动态转轴的位移、应变等测量问题提供了有效方法。     

Surface profile texture characterization of trimmed laminated composite in the stacking sequence direction

The surface texture characterization of laminate composites is complex due to its heterogeneous structure and to the different stratified surface properties. Profile roughness parameters are highly impacted by those different layer properties, and their distributions are relatively spread out. A new filtering technique is proposed to improve the surface roughness parameter efficiency. To present issues from current filtering methods and to highlight this new approach, profile surface roughness taken from trimmed carbon fibre reinforced plastics samples are inspected in the composite stacking sequence using a contact profilometer. For each measurement, several roughness parameters are calculated. The efficiency of different filtering techniques is investigated through the roughness parameters distribution, calculated for up- and down-milling and for different tool wear. The new proposed technique, based on the separate characterization of plateaus and large deep valleys of the composite surface profiles, is found to be particularly efficient on the down-milling face.     

Analysis on the damage behavior of mixed ground during TBM cutting process

Accurate prediction of rock cutting forces of disc cutters is especially significant for the design and construction of tunnel boring machine (TBM). Through the analysis of motion trajectory of TBM disc cutters, a three-dimensional model of rock breaking process of disc cutters is established. In terms of the rock strain which is resulted from the interaction between disc cutters and rock during the process of rock breaking, a three-dimensional cutting forces model is proposed with disc cutters set at certain parameters and in certain sizes. Subsequently, the equation of contacting forces between rock and disc cutter is derived. Moreover, a new method has been presented for the study of the rock breaking theory of the disc cutter and it also provides guidance for the design and application of TBM in tunnel excavation. The three-dimensional model for the rock breaking mechanism is used for predicting the cutting force for the situation of mixed ground.The damage field and the rock failure zone induced by disc cutter for mixed ground are also discussed in this study. In detail, the rock damage zones are divided into two parts, one is the left damage field which located in the outside of disc cutter. The other is the right damage field which located in the outside of disc cutter. The influence of the rock ground dip on the rock failure zone was also studied by parameter analysis.     

基于CAN总线可通信智能电流继电器的设计

通过对一种基于微处理器和CAN总线可通信智能电流继电器的设计,实现了传统的限时速切继电保护功能需要电磁式电流继电器、时间继电器和信号继电器组合在一起才能实现的功能。在此设计的可通信智能电流继电器,不仅能够完成限时速切功能,还可实现现场电器与上位机实现双向通信功能,可对继电器的动作参数（电流值、时间值）进行显示、设定和修改,通过总线系统实达到遥调、遥控的目的,进一步使得继电器的性能得到提高,满足电力系统的要求。     

基于LabVIEW的反力式滚筒制动试验台仿真研究

为有效评价反力式滚筒制动试验台的检测性能,该文在建立反力式滚筒制动试验台力学模型的基础上,使用LabVIEW软件对其制动检测过程进行仿真,并通过与实车制动检测试验所得数据的对比,验证该仿真的准确性。通过对台体参数的输入,可反映不同参数制动试验台的使用性能,以验证产品设计或结构优化的效果。     

神经网络在导弹贮存可靠性预测中的应用

为了更准确预测导弹贮存可靠性,提出基于全局逼近BP网络和局部逼近RBF网络对导弹贮存可靠性进行预测,给出了预测的基本步骤,分别基于BP网络和RBF网络对某型舰舰导弹的贮存可靠性进行了预测,结果表明:这两种网络都能够解决导弹贮存可靠性预测的问题,预测误差均满足要求;RBF网络预测精度略高于BP网络,具有更好的函数逼近能力。RBF网络更适用于导弹贮存可靠性的预测。     

随机共因失效条件下战时合成部队携行备件配置优化研究

装备群在执行作战任务过程中通常会发生共因失效事件,分析共因失效故障对实现装备群的精确化保障具有现实意义。针对战时合成部队装备群遂行任务时,装备携行备件配置优化模型中没有考虑装备受击故障这一类随机共因失效的问题,提出了随机共因失效条件下的备件配置优化方法。建立了装备故障相关条件下的备件需求模型和多约束条件下的携行备件配置优化模型,引入拉格朗日乘子,利用边际效应法求出最优配置方案通过实例对该方法的可行性进行验证。研究结果表明,在装备随机共因失效条件下,所建立的模型可以为多约束携行备件配置优化提供模型参考。     

橡胶带式CVT轴向力建模与分析

通过分析橡胶带式无级变速器轴向夹紧力的形成及其各个调速机构间的平衡关系,运用Simulink软件建立了CVT轴向力变化的仿真模型,针对CVT夹紧力调节中存在的问题,提出了采用变刚度弹簧的优化设计方案,并运用仿真模型,对优化前后的结果进行了对比分析。