孔结构对铜基甲醇合成催化剂宏观反应速率的影响Ⅰ．未中毒颗粒催化剂

催化剂的宏观反应速率受颗粒内扩散过程的影响，而内扩散过程又取决于催化剂颗粒的孔结构。以铜基甲醇合成催化剂为研究体系，通过改变压片压强和共沉淀条件，制备具有不同孔结构参数（比表面、孔隙率、孔径分布、孔容、颗粒密度、曲折因子）的颗粒催化剂，由反应工程中的扩散－反应方程，按照平行交联孔模型计算有效扩散系数，模拟计算单颗粒催化剂在工业生产条件下的宏观反应速率，从而研究孔结构对未中毒铜基甲醇合成催化剂宏观反应速率的影响。     

A fast annealing evolutionary algorithm for global optimization

By combining the aspect of population in genetic algorithms (GAs) and the simulated annealing algorithm (SAA), a novel algorithm, called fast annealing evolutionary algorithm (FAEA), is proposed. The algorithm is similar to the annealing evolutionary algorithm (AEA), and a very fast annealing technique is adopted for the annealing procedure. By an application of the algorithm to the optimization of test functions and a comparison of the algorithm with other stochastic optimization methods, it is shown that the algorithm is a highly efficient optimization method. It was also applied in optimization of Lennard-Jones clusters and compared with other methods in this study. The results indicate that the algorithm is a good tool for the energy minimization problem.     

Theoretical Investigations of the Inclusion Processes of (4-tert-butylphenyl) (3-sulfonatophenyl) (phenyl) Phosphine in β-Cyclodextrin

Quantum mechanical calculations on the (4-tert-butylphenyl)(3-sulfonatophenyl) (phenyl) phosphine/-cyclodextrin inclusion complex werecarried out using semi-empirical calculations. Inclusion process pathways are describedand the most probable structures of the 1:1 complex are sought through a global potentialenergy scan. The calculations suggest that the most stable structure is obtained whenthe aromatic ring bearing the tert-butyl group is includedinto the hydrophobic cavity of the -cyclodextrin from theside of the primary hydroxyl groups.     

Ab initio prediction of helical segments in polypeptides

An ab initio method has been developed to predict helix formation for polypeptides. The approach relies on the systematic analysis of overlapping oligopeptides to determine the helical propensity for individual residues. Detailed atomistic level modeling, including entropic contributions, and solvation/ionization energies calculated through the solution of the Poisson-Boltzmann equation, is utilized. The calculation of probabilities for helix formation is based on the generation of ensembles of low energy conformers. The approach, which is easily amenable to parallelization, is shown to perform very well for several benchmark polypeptide systems, including the bovine pancreatic trypsin inhibitor, the immunoglobulin binding domain of protein G, the chymotrypsin inhibitor 2, the R69 N-terminal domain of phage 434 repressor, and the wheat germ agglutinin.     

Using copositivity for global optimality criteria in concave quadratic programming problems

In this note we specify a necessary and sufficient condition for global optimality in concave quadratic minimization problems. Using this condition, it follows that, from the perspective of worst-case complexity of concave quadratic problems, the difference between local and global optimality conditions is not as large as in general. As an essential ingredient, we here use the-subdifferential calculus via an approach of Hiriart-Urruty and Lemarechal (1990).     

Investigation on the electronically excited state properties of multiwalled carbon nanotube (MDDA) in solution

Since their discovery by Iijima in 1991, carbon nanotubes have inspired considerable research inter-ests worldwide because of their unique structure to-gether with electric, magnetic, thermal conductivity and mechanical properties[1]. Apart from the hexag…     

C302铜基甲醇合成催化剂颗粒设计I．颗粒结构对催化剂宏观活性的影响

以国产C30 2铜基甲醇合成催化剂原粉为母体 ,通过成型模具和成型条件的改变 ,制备了一系列具有不同形状、尺寸和孔结构的催化剂颗粒 ,用宏观活性测试和孔结构表征的方法 ,考察了颗粒结构对催化剂宏观活性的影响。结果表明 ,对于内扩散阻止作用比较明显的工业甲醇合成过程 ,适宜的颗粒结构设计对提高催化剂的利用率具有重要意义 ;当C30 2催化剂颗粒具有 5 5nm～ 7 5nm的平均孔半径、0 4 7左右的孔隙率时 ,其结构比较适宜 ,在此基础上 ,通过改进反应沉淀工艺、提高颗粒的比表面积 ,可以较大幅度的提高催化剂的宏观活性 ;对工业常用的圆柱状C30 2催化剂颗粒 (Φ 5× 5mm) ,采用约 4 0kN·cm- 2 的成型压片强度相对比较适宜。     

球壳轴对称弯曲问题共轭二阶挠度微分方程

提出球壳轴对称弯曲问题共轭二阶挠度微分方程并给出了初等函数解. 球壳微分方程是薄壳理论三大壳之一旋转壳的典型方程. 共轭二阶挠度微分方程是球 壳中微分方程形式最简单的, 是人们最喜爱的挠度微分方程. 挠度微分方程满足边 界条件非常简单, 使球壳的计算得到很大的简化.     

约束全局最优化的水平值估计算法

本文针对约束全局最优化问题,定义并研究了约束水平集上的方差函数,利用牛顿切线法求解方差方程的最大根构造出一种全局优化的水平值估计算法,并基于数论中一致分布佳点集求数值积分的方法建立了它的实现算法,验证了实现算法满足不精确牛顿算法的收敛性条件,从而证明了实现算法的收敛性.初步的数值实验说明了算法的有效性.     

高阶的非线性常微分不等式全局解存在的必要条件

讨论了一类高阶的非线性常微分不等式,得到了该问题的全局解存在的必要条件以及解的存在时间的先验估计,推广了文献[1]的结果.