一类变质性物品在考虑信用期时的补货策略

随着人们物质生活的不断丰富,库存控制系统所处的环境变得既复杂又多变,光靠规模化的经营已经不能满足顾客的需要,经典的EOQ模型的订购批量解也与实际的最优值之间具有很大的差距.由次,本文修改了EOQ模型中的一些假设,在考虑信用期的情况下,研究了需求率为常数、物品存贮寿命为两参数维布尔分布的单一变质性物品在有限计划期内的补货策略,证明了最优补货策略的存在性及惟一性,同时给出了求解最优补货策略的算例,得到了应用更为广泛的结论.     

基于有机化学专业课程培养本科生成就动机的形成——以“对映异构”教学设计为例

Taking the enantiotopic chapter of organic chemistry as an example, this paper explores the teaching reform to form the ability and habit of lifelong learning by improving students' dominant position in learning and to guide undergraduates to cultivate the right achievement motivation. It also tries to provide useful references for the teaching of specialized courses in colleges and universities.     

一种可用于生产效率评价的灰靶评估算法

本文在分析和比较了DEA和灰靶评估两种方法之后，给出一种可用于生产效率评价的灰靶评估算法。该算法由于运用了DEA方法中的“生产效率”概念，弥补了灰靶评估算法不能对不同的被评价单元进行效率评价的不足，从而拓宽了灰靶评估算法的应用背景。文章最后给出实例分析。     

Saccharomyces cerevisiae oxidosqualene‐lanosterol cyclase: A chemistry–biology interdisciplinary study of the protein's structure–function–reaction mechanism relationships

The oxidosqualene cyclases (EC 5.4.99‐) constitute a family of enzymes that catalyze diverse cyclization/rearrangement reactions of (3S)‐2,3‐oxidosqualene into a distinct array of sterols and triterpenes. The relationship between the cyclization mechanism and the enzymatic structure is extremely complex and compelling. This review covers the historical achievements of biomimetic studies and current progress in structural biology, molecular genetics, and bioinformatics studies to elucidate the mechanistic and structure–function relationships of the Saccharomyces cerevisiae oxidosqualene‐lanosterol cyclase‐catalyzed cyclization/rearrangement reaction. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 302–325; 2008: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20157     

《数学实验》课程建设的认识与实践

我们认为 :数学实验 ,就是对数学进行折腾 .我们提出一些饶有趣味而又有深刻背景的问题 ,让学生尝试自己去解决 ,借助于计算机 ,自己动手去折腾 ,在折腾过程中学习 ,观察现象和结果 ,猜测和验证规律 ,尝试和体验数学的探索、发现和应用     

热致相分离法制备食道组织工程用支架的研究

合适的支架是进行组织工程研究必需的条件之一．运用自制的具有较好弹性的无规聚合物聚（L-乳酸-co-己内酯，PLLC），并采用热致相分离法（TIPS）制备了具有不对称孔径的食道组织工程用三维支架．经过对不同成孔条件（包括粗化温度、粗化时间以及聚合物溶液浓度等）的比较和研究，使此支架上表面具有孔径〈10μm，而本体具有50～100μm，甚至〉100gm的不对称多孔支架．并模拟正常食道粘膜层构造，将提取自猪食道的原代上皮细胞和成纤维细胞分别种植于此支架的二面，经HE常规染色，发现在体外培养时间（14d）内，在支架上表面已形成一连续层的上皮细胞层，某些部位甚至多于一层，这与正常食道的上皮细胞层相似．对于成纤维细胞而言，在与上皮细胞层同一视野内所见成纤维细胞较少，因为如果细胞生长在支架内部就很难用常规方法观察得到．但从这些结果可以看到用PLLC制备的多孔支架对细胞没有毒性，且具有一定的支持细胞生长的作用．     

A numerical technique for laminar swirling flow at the interface between porous and homogenous fluid domains

There have been a few recent numerical implementations of the stress‐jump condition at the interface of conjugate flows, which couple the governing equations for flows in the porous and homogenous fluid domains. These previous demonstration cases were for two‐dimensional, planar flows with simple geometries, for example, flow over a porous layer or flow through a porous plug. The present study implements the interfacial stress‐jump condition for a non‐planar flow with three velocity components, which is more realistic in terms of practical flow applications. The steady, laminar, Newtonian flow in a stirred micro‐bioreactor with a porous scaffold inside was investigated. It is shown how to implement the interfacial jump condition on the radial, axial, and swirling velocity components. To avoid a full three‐dimensional simulation, the flow is assumed to be independent of the azimuthal direction, which makes it an axisymmetric flow with a swirling velocity. The present interface treatment is suitable for non‐flat surfaces, which is achieved by applying the finite volume method based on body‐fitted and multi‐block grids. The numerical simulations show that a vortex breakdown bubble, attached to the free surface, occurs above a certain Reynolds number. The presence of the porous scaffold delays the onset of vortex breakdown and confines it to a region above the scaffold. Copyright © 2008 John Wiley & Sons, Ltd.     

Mixed-ligand complexes with trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene terminal and different aromatic polycarboxyl linkers: Synergistic modulation of metallosupramolecular architectures via coordinative and secondary interactions

A series of Co^II, Ni^II, and Cu^II complexes with trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene (bpe) and various polycarboxyl co-ligands have been prepared under general condition and characterized by IR, elemental analysis, and TG-DTA techniques. Single-crystal X-ray diffraction indicates that these complexes display multifarious binuclear, 1-D, and 2-D coordination motifs in virtue of the bridging polycarboxyl building blocks, in which the bpe ligand uniformly adopts the unidentate coordination by using its 4-pyridyl group. Remarkably, higher-dimensional extended networks are further formed with the aid of additional secondary interactions based on bpe (such as H-bonding and π–π stacking). These results demonstrate that bpe is a reliable bifunctional tecton to construct diverse supramolecular architectures via synergistic effect of multiple intermolecular interactions.