Influence of preload discreteness on air-operated separation process of low-shock separation device

To investigate the influence of design parameters on the performance of separation device,the structure and air-operated test of a low-shock separation device are introduced and analyzed in this paper.According to the law of energy conservation and aerodynamics,a mathematical model is built.Because the preload used to ensure the connection reliability has the discreteness,which will influence the separation process,the influence of preload discreteness on the air-operated separation process is simulated and tested.Simulation results are consistent with the experimental results.It is shown that the change of preload has an obvious influence on the separation process.The study is useful for the design and optimization of separation device.     

Deformation characteristics of surrounding rock of broken and soft rock roadway

A similar material model and a numerical simulation were constructed and are described herein. The deformation and failure of surrounding rock of broken and soft roadway are studied by using these models. The deformation of the roof and floor, the relative deformation of the two sides and the deformation of the deep surrounding rock are predicted using the model. Measurements in a working mine are compared to the results of the models. The results show that the surrounding rock shows clear rheological features under high stress conditions. Deformation is unequally distributed across the whole section. The surrounding rock exhibited three deformation stages: displacement caused by stress concentration, rheological displacement after the digging effects had stabilized and displacement caused by supporting pressure of the roadway. Floor heave was serious, accounting for 65% of the total deformation of the roof and floor. Floor heave is the main reason for failure of the surrounding rock. The reasons for deformation of the surrounding rock are discussed based on the similar material and numerical simulations.     

Relationships between gas reservoir and the evolution of stope surrounding rock fracture at the process of mining the closed distance protection layer

Overburden rock movements and fracture developments occur during mining activities. Consequently, relief gas reservoirs and migration in coal seams being mined as well as in near distant coal seams appear. We considered a gas disaster management project and rules on stope relief of gas flows together and explored a gas reservoir and the evolution of stope surrounding rock fractures in the process of mining near distant protective layers by physical simulation, numerical simulation and field testing. Different techniques provide evidence of the rules of interaction of gas reservoirs and the evolution of surrounding rock fractures and are able to find accurately the gas-rich regions around the stope. Finally, we found that these rules can provide a basis for taking measures to prevent gas accidents in the protective layer of the coalface as well as for demonstrating and designing programs to drain high concentrations of gas from the gob.     

不同分布φ^~混合序列的弱大数定理

通过利用矿混合序列的矩不等式推导出φ^~混合阵列行和的一个弱大数定理,并由φ^~混合阵列行和弱大数定理得出不同分布矿混合序列的一个弱大数定理。     

VSC—HVDC系统的控制策略及其仿真研究

建立了VSC-HVDC系统的数学模型,基于鲁棒控制理论,将系统对VSC-HVDC的控制目标转化为对其交流侧有功和无功电流的控制来实现,并进行了控制方案设计．仿真实验表明所设计的控制器能够快速反应达到预定的指令目标,具有良好的鲁棒性．     

水晶球模拟在R＆D决策中的运用

研究与开发（Research and Development,R＆D）投资、传统贴现现金流量（DiscountedCash Flow,DCF）方法忽略了项目自身管理弹性的价值;实物期权虽能较好地捕捉管理弹性的价值,却未能有效解决高度不确定环境下参变量的波动性问题;蒙特卡罗模拟能解决参变量的波动性问题,但需要复杂的计算机程序来解决算法问题.作者在分析实物期权的基础上,运用蒙特卡罗理论,使用水晶球软件来进行R＆D决策分析.通过实例证明,水晶球模拟方法可以更为科学有效地解决高度不确定条件下的R＆D决策问题.     

NO在HZSM-5分子筛中吸附的实验与分子模拟

通过实验测定了NO在HZSM-5型中部分条件下的吸附性能,然后运用巨正则系综Monte Carlo方法（grand canonical assemblage Monte Carlo,GCMC）建立了相应的吸附模型,模拟计算了其相应的吸附行为．在实验与模拟结果相吻合的基础上,进一步模拟计算了NO在HZSM-5型分子筛中的吸附等温线、吸附微观构型及吸附热等性质．计算结果表明,随着硅铝比及分子筛中的自由体积增大,其对NO的吸附量增加,NO主要吸附在十元环直孔道和Zigzag形状的十元环孔道的中央;氢离子的存在在一定程度上阻碍了NO的扩散;在吸附量相同的条件下,NO在HZSM-5型分子筛的吸附热随着硅铝比的升高而升高．     

用Pro/E对过约束运动平台动态仿真分析研究

针对过约束多体运动机构的动态受力分析难点,以一个具体的多曲轴运动平台为例,提出一种基于Pro/E中Mechanism仿真模块进行动态仿真的解决方法。在Pro/E中进行了3维建模;针对分析的重点,对系统模型进行了适当简化;并结合虚拟样机技术在Pro/E中的具体运用,对简化模型进行动态仿真;并运用仿真结果分析了各类因素对该机构运动及受力的影响,提出了优化设计方案。     

基于宏程序及数控仿真技术研究特殊球体的加工

应用三轴联动的数控立式铣床、基于宏程序及数控仿真加工技术、设计完成在正立方体内铣削自由滚动球体的方案。通过对正立方体和球体的三种空间关系的研究,巧妙设计球缺加工变量,合理建立数学模型及数学关系表达式,实现了三坐标立体球面的手工编程,达到加工精度最高,加工时间最省的目的;同时提供了一种新型的球体加工方法。