应用Monte Carlo方法模拟爆轰产物状态方程的研究进展

 应用Monte Carlo方法模拟爆轰产物状态方程,区别于建立在球形分布分子势基础上的传统爆轰产物状态方程计算方法,从原子水平上直接模拟实际炸药的爆轰产物状态方程,克服了传统方法中混合产物状态方程不精确的缺点。综述了该方法的历史背景及发展现状。对模拟中宏观量的描述、统计平均的计算、势函数的选取及边界条件进行了详尽描述。     

FSDD运行模态参数识别方法中不确定性的计算

运行模态参数识别是一种只利用响应数据进行模态分析的方法。环境激励条件下获得的识别结果会存在随机不确定性,这种不确定程度可以通过模态参数的统计特性进行描述评价。以运行模态分析中的频域空间域分解方法（FSDD）为研究对象,通过对整个模态识别算法进行摄动分析,确定出模态参数对测量误差的灵敏度,实现了模态参数方差的计算。计算过程分为四步：第一步,响应信号功率谱矩阵中噪声方差的估计;第二步,增强功率谱方差的计算;第三步,极点协方差的计算;第四步,模态参数方差的计算。最后通过一个4自由度仿真算例与张家港桥梁实测算例对所给出的方法进行了验证与应用。     

浅海相干声场不确定性研究

提出一种采用随机响应面法求解浅海中含不确定参数波动方程的方法.将海洋环境不确定参数表示为标准随机变量,利用Hermite多项展开式表示相干声场的随机响应,用概率配点法求解随机多项式系数后,获得相干声场的近似表达式.通过与Monte Carlo法、声场位移法比较,表明本文方法计算精度和效率较高.     

Gruhn-Hess两体势修正模型向列相液晶微滴的Monte Carlo模拟

基于Gruhn-Hess两体势修正模型,用Monte Carlo方法模拟向列相液晶微滴.Gruhn-Hess两体势是空间各向异性的,修正模型的势参数依赖于液晶的弹性常数K₁₁、K₂₂、K₃₃及表面弹性常数K₁₃.假设向列相液晶微滴具有自由表面,在低温下计算分子二阶序参数和切向内禀强度在微滴内不同区域的变化,并与Gruhn-Hess两体势模型一作对比分析.结果表明:附加K₁₃项的修正模型在微滴表面产生内禀锚定,其大小决定了内禀易取向方向及内禀锚定强度的大小,且内禀强度的大小与K₃₃/K₁₁值有关;空间不完整的向列相液晶微滴由内层到外层有序度逐渐降低.     

逐次Ⅰ型混合截尾下基于FGM copula的应力强度模型可靠性估计

在逐次Ⅰ型混合截尾样本下,研究具有相关性应力-强度模型的可靠性.假设应力和强度分布为参数不同的指数分布,选用FGM copula作为连接函数构造联合分布,得到参数和可靠度的极大似然估计(MLEs)、贝叶斯估计和对应渐近置信区间、HPD置信区间.通过Monte Carlo模拟方法,获得不同样本量不同截尾方案下估计值的数值...     

Monte Carlo simulation of ramified aggregates onhetero-substrates

We have studied the aggregation of particles on a hetero-substrate consisting of two different substrates A and B with finite surface barriers E_AB and E_BA between the AB and BA boundaries, respectively. With the diffusion energy limited aggregation (DELA) model, we find that the number of clusters and the mean radius of gyration of the clusters are dependent on the surface barriers E_AB and E_BA. For the case with a constant of E_BA, a series of minima are summarized as E_AB= (E₀- k_BAE_BA)/ k_AB with k_AB and k_BA being two integers, for main minima (k_BA=k_AB- 1) and two local minima (k_BA=k_AB and k_BA=k_AB + 1) between two neighbouring main minima.     

Monte Carlo simulations of biaxial structure in thin hybrid nematic film based upon spatially anisotropic pair potential

Hybrid nematic films have been studied by Monte Carlo simulations using a lattice spin model, in which the pair potential is spatially anisotropic and dependent on elastic constants of liquid crystals. We confirm in the thin hybrid nematic film the existence of a biaxially nonbent structure and the structure transition from the biaxial to the bent-director structure, which is similar to the result obtained using the Lebwohl--Lasher model. However, the step-like director's profile, characteristic for the biaxial structure, is spatially asymmetric in the film because the pair potential leads to K₁ ≠ K₃. We estimate the upper cell thickness to be 69 spin layers, in which the biaxial structure can be found.     

Calculations of radioactivity and afterheat in the components of the CSNS target station

This paper shows the calculations of radioactivity and afterheat in the components of the China Spallation Neutron Source (CSNS) target station, with the Monte Carlo codes LAHET, MCNP4C and the multigroup code CINDER'90. These calculations provide essential data for the detailed design and maintenance of the CSNS target station.     

Inverse Monte Carlo study on effective interaction potential of Ag--Rh alloy from pair correlation functions

This paper presents an inverse Monte Carlo method to reconstruct pair interaction potential from pair correlation function. This approach adopts an iterative algorithm on interaction potential to fit known pair correlation function by compelling deviations of canonical average to meet with Hamiltonian parameters on a basis of statistical mechanism. The effective interaction potential between particles in liquid Ag--Rh alloys has been calculated with the inverse Monte Carlo method. It demonstrates an effective and simple way to obtain the effective potential of complex melt systems.     

超薄膜生长的Monte Carlo模拟研究

利用Monte Carlo(MC)方法模拟研究了薄膜生长的初始阶段岛的形貌和岛的尺寸与基底温度和入射粒子剩余能量之间的关系.模型中考虑了粒子的沉积、吸附粒子的扩散和蒸发等过程.结果表明当基底温度从200K变化到260K时,岛的形貌经历了一个从分散生长逐渐过渡到分形生长的过程,并且在较低温度(200K)下,随入射粒子剩余能量的增加,岛的形貌也经历了同样的变化过程.进一步研究证明,随着基底温度的升高或入射粒子剩余能量的增加,沉积粒子的扩散能力显著增强,从而使岛的形貌发生了改变.