The kinetics of the decomposition of N2O on a catalytic surface is simulatedby means of the Monte Carlo technique. The results show that the reaction rate is dependent not only to the mole fraction of N2O in gas phase...The kinetics of the decomposition of N2O on a catalytic surface is simulatedby means of the Monte Carlo technique. The results show that the reaction rate is dependent not only to the mole fraction of N2O in gas phase, but also to the surface-O coverage.The surface-O coverage increases with the increasing of the mole fraction of N2O in gas.When the reaction gas is pure N2O, the surface-O coverage can be a constant, and it isindependent to the pressuze of N2O gas.展开更多
应力强度因子是预测荷载作用下结构中裂纹产生和扩展的重要参数。半解析的比例边界有限元法结合了有限元和边界元法的优势,在裂纹尖端或存在奇异应力的区域不需要局部网格细化,可以直接提取应力强度因子。在比例边界有限元法计算应力强...应力强度因子是预测荷载作用下结构中裂纹产生和扩展的重要参数。半解析的比例边界有限元法结合了有限元和边界元法的优势,在裂纹尖端或存在奇异应力的区域不需要局部网格细化,可以直接提取应力强度因子。在比例边界有限元法计算应力强度因子的框架下,引入随机参数进行蒙特卡罗模拟(Monte Carlo simulation, MCS),并提出一种新颖的基于MCS的不确定量化分析。与直接的MCS不同,采用奇异值分解构造低阶的子空间,降低系统的自由度,并使用径向基函数对子空间进行近似,通过子空间的线性组合获得新的结构响应,实现基于MCS的快速不确定量化分析。考虑不同荷载状况下,结构形状参数和材料属性参数对应力强度因子的影响,使用改进的MCS计算应力强度因子的统计特征,量化不确定参数对结构的影响。最后通过若干算例验证了该算法的准确性和有效性。展开更多
概率潮流(probabilistic load flow,PLF)计算是电力系统稳态运行分析的重要工具。传统半不变量法概率潮流(PLF based on cumulant method,PLF-CM)要求各输入变量相互独立,这使其不能直接应用于输入变量具有相关性的场合。针对这一情况,...概率潮流(probabilistic load flow,PLF)计算是电力系统稳态运行分析的重要工具。传统半不变量法概率潮流(PLF based on cumulant method,PLF-CM)要求各输入变量相互独立,这使其不能直接应用于输入变量具有相关性的场合。针对这一情况,提出一种基于Cholesky分解的计及输入变量相关性的PLF-CM计算方法。同时,为解决一些输入变量的半不变量难以被常规数值方法求解的问题,提出基于蒙特卡罗抽样的方法,该方法利用输入变量的样本计算其半不变量。对改进的IEEE 14节点系统进行仿真计算,结果验证了所提方法的有效性、准确性和实用性。在此基础上利用所提方法分析了风速相关性对系统运行特性的影响。结果表明系统运行特性受风速相关性影响较大。展开更多
Using Monte Carlo (MC) method, we sinuilate two possible mechanisms of N2O decomPosition reaction on a catalyst. One of them is in good agreement with the experiment. On the other hand, we also investigate the nature ...Using Monte Carlo (MC) method, we sinuilate two possible mechanisms of N2O decomPosition reaction on a catalyst. One of them is in good agreement with the experiment. On the other hand, we also investigate the nature of the reaction rate oscillation in N2O decomposition. The results show that besides simulating mechahisms of surface reactions, MC method can also be an effective tool to investigate the kinetic behavior of complex reactions.展开更多
The decomposition of N2O on a catalytic surface was simulated by the Monte Carlo method. The results show that both reaction rate and surface coverage oscillate with time. Fractal analysis of the time-series of surfac...The decomposition of N2O on a catalytic surface was simulated by the Monte Carlo method. The results show that both reaction rate and surface coverage oscillate with time. Fractal analysis of the time-series of surface coverages indicates that the oscillation observed has an attractor. The oscillation is chaotic in nature and the attractor is a fractal with a dimension about 3.5 when the rate constant k2 of the elementary step which produces O2 is large enough.展开更多
文摘The kinetics of the decomposition of N2O on a catalytic surface is simulatedby means of the Monte Carlo technique. The results show that the reaction rate is dependent not only to the mole fraction of N2O in gas phase, but also to the surface-O coverage.The surface-O coverage increases with the increasing of the mole fraction of N2O in gas.When the reaction gas is pure N2O, the surface-O coverage can be a constant, and it isindependent to the pressuze of N2O gas.
文摘应力强度因子是预测荷载作用下结构中裂纹产生和扩展的重要参数。半解析的比例边界有限元法结合了有限元和边界元法的优势,在裂纹尖端或存在奇异应力的区域不需要局部网格细化,可以直接提取应力强度因子。在比例边界有限元法计算应力强度因子的框架下,引入随机参数进行蒙特卡罗模拟(Monte Carlo simulation, MCS),并提出一种新颖的基于MCS的不确定量化分析。与直接的MCS不同,采用奇异值分解构造低阶的子空间,降低系统的自由度,并使用径向基函数对子空间进行近似,通过子空间的线性组合获得新的结构响应,实现基于MCS的快速不确定量化分析。考虑不同荷载状况下,结构形状参数和材料属性参数对应力强度因子的影响,使用改进的MCS计算应力强度因子的统计特征,量化不确定参数对结构的影响。最后通过若干算例验证了该算法的准确性和有效性。
文摘概率潮流(probabilistic load flow,PLF)计算是电力系统稳态运行分析的重要工具。传统半不变量法概率潮流(PLF based on cumulant method,PLF-CM)要求各输入变量相互独立,这使其不能直接应用于输入变量具有相关性的场合。针对这一情况,提出一种基于Cholesky分解的计及输入变量相关性的PLF-CM计算方法。同时,为解决一些输入变量的半不变量难以被常规数值方法求解的问题,提出基于蒙特卡罗抽样的方法,该方法利用输入变量的样本计算其半不变量。对改进的IEEE 14节点系统进行仿真计算,结果验证了所提方法的有效性、准确性和实用性。在此基础上利用所提方法分析了风速相关性对系统运行特性的影响。结果表明系统运行特性受风速相关性影响较大。
文摘Using Monte Carlo (MC) method, we sinuilate two possible mechanisms of N2O decomPosition reaction on a catalyst. One of them is in good agreement with the experiment. On the other hand, we also investigate the nature of the reaction rate oscillation in N2O decomposition. The results show that besides simulating mechahisms of surface reactions, MC method can also be an effective tool to investigate the kinetic behavior of complex reactions.
文摘The decomposition of N2O on a catalytic surface was simulated by the Monte Carlo method. The results show that both reaction rate and surface coverage oscillate with time. Fractal analysis of the time-series of surface coverages indicates that the oscillation observed has an attractor. The oscillation is chaotic in nature and the attractor is a fractal with a dimension about 3.5 when the rate constant k2 of the elementary step which produces O2 is large enough.
