多点驱动带式输送机功率平衡机制研究

针对多点驱动带式输送机功率不平衡降低输送效率及生产寿命问题,对多电机间的协调控制进行研究。对传统偏差耦合多电机协调控制结构进行了改进,增加了基于转速功率控制的同步误差补偿器,通过求取所有电机的平均转速和单台电机的转速差,利用PI控制器,同时结合每台电机的系统转速跟踪误差,反馈补偿到每台电机的控制回路进行多电机协调控制。仿真结果表明,系统可以在负载变化扰动的情况下有效降低各电机的同步误差,特别是对系统刚启动时负载不均衡导致的电机功率不平衡问题,改进结构可以有效实现多电机间的功率平衡分配。     

全自动影像测量仪中双相机精确定位方法研究

为了实现影像测量仪双相机的精确定位,以满足批量多种类零件自动化测量需求。在现有的影像测量仪上引入由大视野相机构成的视觉引导模块,文中以改进后的影像测量仪为平台,利用大视野相机得到标定板的角点位置信息,结合小视野相机获得的实际位置信息,通过仿射变换建立两者之间的坐标转换关系,确定双相机之间的位置关系,实现双相机之间的相互精确定位。定位实验结果表明了文章所提方法的有效性,相对于传统定位方法其定位精度提高了16%,能够满足批量多种类零件自动化测量的需求,为后续的自动测量工作奠定了基础。     

Dynamic tensile strength and failure mechanisms of thermally treated sandstone under dry and water-saturated conditions

To study the tensile strength and failure mechanisms of rock with hydro-thermal coupling damage under different loading rates, a series of static and dynamic splitting tests were conducted on thermally treated sandstone under dry and water-saturated conditions. Experimental results showed that high temperatures effectively weakened the tensile strength of sandstone specimens, and the P-wave velocity declined with increasing temperature. Overall, thermal damage of rock increased gradually with increasing temperature, but obvious negative damage appeared at the temperature of 100 °C. The water-saturated sandstone specimens had lower indirect tensile strength than the dry ones, which indicated that water−rock interaction led to secondary damage in heat-treated rock. Under both dry and water-saturated conditions, the dynamic tensile strength of sandstone increased with the increase of strain rate. The water-saturated rock specimens showed stronger rate dependence than the dry ones, but the loading rate sensitivity of thermally treated rock decreased with increasing treatment temperature. With the help of scanning electron microscopy technology, the thermal fractures of rock, caused by extreme temperature, were analyzed. Hydro-physical mechanisms of sandstone under different loading rate conditions after heat treatment were further discussed.     

甲烷氧化偶联反应的研究进展

通过对于甲烷氧化偶联法制取乙烯的反应过程中的各方面性能研究,对其进行具体分析,探讨针对不同性能的催化剂对于反应产物的各方面影响来进行具体分析。同时对于不同反应条件下的不同反应方面的影响也进行细致的研究分析,通过对于甲烷氧化偶联反应过程中的催化剂的催化机理进行研究。     

BHDDF350型联轴器失效分析及改进设计

联轴器在旋转过程中连续传递扭矩且具备一定缓冲和减振的保护作用,而又不改变初始旋转方向和扭矩大小,BHDDF350型联轴器是某型矿用减速机与电机之间的扭矩传动部件。从该型联轴器的运行工况、结构分布、损坏形式等方面查找并分析了其失效原因,依据其受力分析提出了改进型设计方案,以供业内参考。改进设计后的联轴器,弹性块受力均匀,且最大受力降比30%以上,可有效延长联轴器的整体使用寿命,减少了煤矿井下日常的维护工作量。     

Finite element modeling of thermo-active diaphragm walls

There are two major challenges faced by modern society: energy security, and lowering carbon dioxide gas emissions. Thermo-active diaphragm walls have a large potential to remedy one of these problems, since they are a renewable energy technology that uses underground infrastructure as a heat exchange medium. However, extensive research is required to determine the effects of cyclic heating and cooling on their geotechnical and structural performance. In this paper, a series of detailed finite element analyses are carried out to capture the fully coupled thermo-hydro-mechanical response of the ground and diaphragm wall. It is demonstrated that the thermal operation of the diaphragm wall causes changes in soil temperature, thermal expansion/shrinkage of pore water, and total stress applied on the diaphragm wall. These, in turn, cause displacements of the diaphragm wall and variations of the bending moments. However, these effects on the performance of diaphragm wall are not significant. The thermally induced bending strain is mainly governed by the temperature differential and uneven thermal expansion/shrinkage across the wall.     

基于双向耦合的东安513型发动机整机多物理场研究

以东安513型汽油发动机整机为例,基于ANSYS有限元分析软件对其进行流体场、瞬态温度场以及瞬态结构场的多物理场双向耦合研究,实现了对发动机实际工况下的有限元分析。研究了发动机整机在实际工况下的受力以及密封情况,并对现有发动机组合结构存在的密封缺陷进行优化调整。文中详细阐述了在分析过程中涉及到的关键技术和要点,并最终获得了发动机整机实际工作状态下的多个结果云图。根据分析结果云图可以发现,发动机在热载荷、螺栓预紧力以及爆破压力的共同影响下,会使整机发生一定的形变,这种变形会影响其工作状况下的密封性能。通过对分析结果的研究,最终选择调整螺栓预紧力的大小和分布来提高发动机密封性能。     

湿热磷化工耦合绿色生产饲料磷酸盐技术

介绍了以磷矿、湿法磷酸和黄磷尾气耦合生产饲料级磷酸二氢钙（MCP）、磷酸一二钙（MDCP）、磷酸氢钙（DCP）和磷酸三钙（DFP）以及专用的磷酸一二三钙（MDTCP）等饲料磷酸盐的绿色可持续发展的生产方法。该方法经济地利用了磷矿中的钙资源,节约了传统方法生产饲料磷酸盐需要开采原生石灰石的资源;同时,不仅经济地开拓了黄磷尾气的利用途径、消灭了“天灯”、节约了能源,又将生产饲料磷酸盐的磷矿中的氟资源全部回收;创新耦合生产带来了磷矿中的磷、钙、氟的全资源利用。     

Injection molding,debinding and sintering of ZrO2 ceramic modified by silane couping agent

In this paper, Injection molding, debinding and sintering of ZrO₂ ceramic modified by silane coupling agent (A151) were studied by measuring the melt index of feedstocks, the soluble removal ratio of green parts, the bending strength of green and sintered parts, the surface and fractural morphologies of sintered parts. The results showed that the melt index of ZrO₂ feedstocks, the weight removal ratio of soluble binders, and the bending strength of green parts increased after adding A151. When the density of sintered parts was between 5.97–6.03 g/cm³, it was not the main factor influencing the bending strength. However, the bending strengths of sintered parts decreased due to microcrack formation when thermal debinding process was too fast or slow. The interesting phenomenon of the abnormal grain growth with transgranular fracture in the sintered parts obviously occurred above 1550 ℃, which made the effect of sintering temperature on the strength become complex.