立方非线性Schr?dinger方程的动力学行为分析

本文采用辛算法，研究了立方非线性Schr?dinger方程在不同的空间离散下的动力学行为，并讨论了其在不同的非线性参数下的动力学性质。 我们指出，系统的守恒量在长时间的演化下保持不变，但对于强非线性，不同的空间离散精度，将导致不同的动力学行为。     

Mei Symmetry and Lie Symmetry of Relativistic Hamiltonian System

The Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are studied. The definition and criterion of the Mei symmetry and the Lie symmetry of the relativistic Hamiltonian system are given. The relationship between them is found. The conserved quantities which the Mei symmetry and the Lie symmetry lead to are obtained.An example is given to illustrate the application of the result.     

植物种群数量研究的Lewis－Leslie区间矩阵模型

利用区间动力系统原理，建立了研究植物种群数量变化趋势的Ｌｅｗｉｓ－Ｌｅｓｌｉｅ区间矩阵模型，并且获得判断种群消长的充分或必要条件．研究新疆莫索湾沙区白梭梭种群的实践标明，该类模型对某些植物种群是有一定应用范围的．特别需要指出，模型的最大特点在于元素的相对不确定性．只要知道其取值范围即可     

Hydration in drug design. 3. Conserved water molecules at the ligand-binding sites of homologous proteins

Summary Water molecules are known to play an important rôle in mediating protein-ligand interactions. If water molecules are conserved at the ligand-binding sites of homologous proteins, such a finding may suggest the structural importance of water molecules in ligand binding. Structurally conserved water molecules change the conventional definition of binding sites by changing the shape and complementarity of these sites. Such conserved water molecules can be important for site-directed ligand/drug design. Therefore, five different sets of homologous protein/protein-ligand complexes have been examined to identify the conserved water molecules at the ligand-binding sites. Our analysis reveals that there are as many as 16 conserved water molecules at the FAD binding site of glutathione reductase between the crystal structures obtained from human and E. coli. In the remaining four sets of high-resolution crystal structures, 2–4 water molecules have been found to be conserved at the ligand-binding sites. The majority of these conserved water molecules are either bound in deep grooves at the protein-ligand interface or completely buried in cavities between the protein and the ligand. All these water molecules, conserved between the protein/protein-ligand complexes from different species, have identical or similar apolar and polar interactions in a given set. The site residues interacting with the conserved water molecules at the ligand-binding sites have been found to be highly conserved among proteins from different species; they are more conserved compared to the other site residues interacting with the ligand. These water molecules, in general, make multiple polar contacts with protein-site residues.     

模糊综合评价中的若干问题

本文对当前广泛应用的模糊综合评价方法，讨论了评价因素间的补偿作用及评定级别关于权变化的稳定性问题，建立了补偿量及保级区间的定义，并证明了它们的若干性质及计算方法。从而丰富了评价信息，为全面认识参评样品的质量状态，提供了重要的辅助信息。     

Optimal ordering and pricing policy with supplier quantity discounts and price-dependent stochastic demand

We study a joint ordering and pricing problem for a retailer whose supplier provides all-unit quantity discount for the product. Both generalized disjunctive programming model and mixed integer nonlinear programming model are presented to formulate the problem. Some properties of the problem are analysed, based on which a solution algorithm is developed. Two numerical examples are presented to illustrate the problem, which are solved by our solution algorithm. Managerial analysis indicates that supplier quantity discount has much influence on the ordering and pricing policy of the retailer and more profit can be obtained when the supplier provides quantity discount.     

The inventory model for trade credit in economic ordering policies of deteriorating items in a supply chain system

In 1994, professors Jaggi and Aggarwal presented the economic ordering policies of deteriorating items in the presence of trade credit using a discounted cash-flows (DCF) approach. This paper discusses the same problem as that of Jaggi and Aggarwal and indicates that some approximations to the optimal cycle times proposed by Jaggi and Aggarwal are inappropriate sometimes. A theorem is derived out to find the optimal cycle time. With that theorem, a simple algorithm is developed to locate the optimal cycle time.     

教学质量评估的定量比较评价模型

依据华南农业大学 2 0 0 2学年第一学期课堂教学质量评估卡的调查数据 ,利用层次分析法建立了学生评价教师教学质量的定量评价模型 P =WR,并应用该模型对担任数学类课程的 1 3位教师的课堂教学质量作了定量比较分析 .分析结果表明 ,近几年来的扩招 ,对教师的教学提出了新的要求 ,在教学内容、教学手段、教学方法等方面 ,应做出相应的调整 ,才能收到好的教学效果 .     

Finsler metrics of scalar flag curvature with special non-Riemannian curvature properties

In this paper, we study Finsler metrics of scalar flag curvature. We find that a non-Riemannian quantity is closely related to the flag curvature. We show that the flag curvature is weakly isotropic if and only if this non-Riemannian quantity takes a special form. This will lead to a better understanding on Finsler metrics of scalar flag curvature.      

相空间中非Chetaev型非完整系统的Lie对称性与守恒量

研究相空间中非Ｃｈｅｔａｅｖ型非完整系统的Ｌｉｅ对称性与守恒量。首先利用微分方程在无限小变换下的不变性建立Ｌｉｅ对称所满足的确定方程的限制方程，给出了结构方程和守恒量；其次研究系统的Ｌｉｅ对称逆问题；最后举例说明结构的应用。