Derivation of a universal estimate for the stiffness of carbon nanotubes

An algorithm has been developed based on numerical simulation to relate physical geometry to the Young’s modulus of symmetric and asymmetric single-walled carbon nanotubes (SWCNTs). A large number of finite element results for the stiffness of SWCNTs has been categorized into three main classes (i.e., armchair, zigzag and chiral) and the best curve fitting function has been obtained to describe the relation between the geometry of SWCNTs and their stiffness. For two standard configurations of carbon nanotubes (i.e., armchair and zigzag), four equations referring to geometry parameters (n, m) and diameter (d) have been introduced. To find the size dependence of asymmetric nanotubes, three-dimensional surfaces of stiffness (E(n, m)) have been used. However, since the stiffness of asymmetric nanotubes depends upon n and m, it was impossible to define any diameter dependency. To account for the hidden mechanical behavior of asymmetric SWCNTs, a new physical factor (CF) was introduced as the major novelty in this work. The proposed CF converts any asymmetric geometry (n, m) into a value between 0 and 1. The CF for a chiral nanotube can imply the percentage of similarity in its mechanical properties to the two standard symmetric configurations. Based on the CF concept, a new equation is derived to predict the Young’s modulus of asymmetric carbon nanotubes based on the symmetric prediction of standard models. The new physical factor (CF) which is developed in this study can be useful for the characterization of SWCNTs and the selection of all configurations.     

智能算法在晶体色散方程参量反演中的比较研究

为了研究智能优化算法在不同晶体材料色散方程参数反演中的迭代搜索性能问题,根据已测石英和方解石晶体的实验数据,分别采用遗传算法、模拟退火算法和遗传模拟退火算法应用于晶体色散方程的参数反演中,获得了晶体修正的塞耳迈耶尔方程的参量,同时比较了三种算法在迭代搜索性能、算法稳定性、计算时间和差方和等之间的差异,结果表明,三种算法在晶体色散方程参数反演时都可以得到满意的结果,但是,由于遗传模拟退火算法同时具备遗传算法的快速全局搜索性能和模拟退火算法的极强局部搜索性能,使得在晶体色散方程参数反演中的优化效果更优.因此在建立其它材料色散方程时建议采用遗传模拟退火算法,而且这一结果对研究混合智能算法的迭代搜索性能也是有帮助的.     

Scheduling jobs with release times preemptively on a single machine to minimize the number of late jobs

We give a direct combinatorial O(n³logn) algorithm for minimizing the number of late jobs on a single machine when jobs have release times and preemptions are allowed. Our algorithm improves the earlier O(n⁵) and O(n⁴) dynamic programming algorithms for this problem.     

On random variational inclusions with random fuzzy mappings and random relaxed cocoercive mappings

In this paper, we introduce and study the random variational inclusions with random fuzzy and random relaxed cocoercive mappings. We define an iterative algorithm for finding the approximate solutions of this class of variational inclusions and establish the convergence of iterative sequences generated by proposed algorithm. Our results improve and generalize many known corresponding results.     

分式规划模糊投资组合模型的遗传算法求解

将预期收益率表示为模糊数,以E-SV风险测度为基础给出了组合证券投资决策的效用函数,并建立了基于分式规划的模糊投资组合选择模型,考虑到模型求解的复杂性,我们利用遗传算法构造罚函数对模型进行了求解,并通过实例,验证了该模型解法的可行性和有效性.     

格值命题逻辑系统L_(2n+1)P(X)中基于半正则广义文字的自动推理算法

在格值命题逻辑系统L2n+1P(X)上,提出了半正则的正广义文字和半正则的负广义文字的概念,进一步给出了半正则广义子句和半正则广义子句集的定义,详细地讨论了L2n+1P(X)上以中界元M为归结水平的半正则广义文字之间的M-归结性,最后,给出了L2n+1P(X)上基于半正则广义文字的归结水平为M的归结自动推理算法,并验证了其可靠性和完备性.     

带点弧约束的最短路问题：复杂性和算法

本文首先提出了带点弧约束的最短路问题，证明了该问题属于ＮＰ－Ｃ，然后给出了一个伪多项式时间算法．最后给出了最小成本最短路问题的一个时间复杂性为Ｏ（ｎ２）的算法．     

迭代法计算多元酸碱滴定的pH

介绍了迭代法计算多元弱酸碱滴定pH计算原理,使用一个公式,用Excel计算多元酸碱滴定过程中溶液pH值,列举了H3PO4和Na2CO3滴定的pH值计算方法.