Optical resolution of racemic amino acid derivatives with molecularly imprinted membranes bearing oligopeptide tweezers

Molecularly imprinted polymeric membranes were prepared from various oligopeptide tweezers by the adoption of N‐α‐tert‐butoxycarbonyl‐D ‐tryptophan (Boc‐D ‐Trp) or N‐α‐tert‐butoxycarbonyl‐L ‐tryptophan (Boc‐L ‐Trp) as a print molecule. The chiral recognition ability of the formed molecular recognition sites was dependent on the absolute configuration of the print molecule adopted in the membrane preparation (molecular imprinting) process, whereas the candidate oligopeptide tweezers consisted of the L ‐amino acid residues. In other words, the membranes imprinted by the D ‐isomer recognized the D ‐isomer in preference to the corresponding L ‐isomer, and vice versa. The affinity constant between the target molecule and the chiral recognition site from the oligopeptide tweezers was higher than that from a single‐strand oligopeptide derivative. Those membranes selectively transported the enantiomer, which was preferentially incorporated into the membrane by dialysis. The permselectivities for these membranes exceeded their adsorption selectivities. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 385–396, 2005     

Mode competition in acousto-optically Q-switched planar waveguide lasers

Multi-mode rate equations have been developed to investigate mode competition in high-power acousto-optically Q-switched planar waveguide lasers. The mode competition arises from coupling effects and temporal losses in the transform between guided modes and free-space propagation. Pulse-to-pulse instability and temporal beam distortions are enlarged by mode competition when the laser works in the multi-mode regime. The influence of parasitic oscillation is also discussed. A Nd:YAG planar waveguide laser has been established with a folded hybrid/unstable resonator. A maximum average power of 83 W with a beam propagation factor is obtained. The theoretical simulation agrees well with the experimental observation.     

竞争环境下供应链的BOPS合作策略及其对交通拥堵改善的影响

针对由一个拥有线上直销渠道的制造商以及一个线下零售商组成的供应链,考虑消费者对不同渠道的偏好构建了供应链博弈模型,研究了竞争环境下制造商与零售商的最优BOPS合作策略,并分析了BOPS合作在改善交通拥堵方面的作用。研究表明,BOPS合作在缓解供应链双重边际效应的同时会加剧渠道之间的价格竞争,所以并不总是对供应链有利;仅当消费者线上渠道偏好程度比较低且线下麻烦成本比较大时,制造商和零售商才会都从BOPS合作中受益从而自愿达成合作,其他情形下制造商可根据供应链利润变化设计转移支付契约促成与线下零售商的BOPS合作并实现双赢;此外,一定条件下BOPS合作能够通过调整渠道需求结构,在保证供应链成员利润的同时对交通拥堵改善也带来正向作用。     

Competition between halogen bond and hydrogen bond in complexes of superalkali Li3S and halogenated acetylene XCCH (X = F,Cl, Br,and I)

Complexes of superalkali Li₃S and XCCH (X = F, Cl, Br, and I) have been studied with theoretical calculations at the MP2/aug‐cc‐pVTZ level. Three types of structures are found: (A) the X atom combines with the S atom through a halogen bond; (B) the X atom interacts with the π electron of Li₃S by a π halogen bond; (C) the H atom combines with the S atom through a hydrogen bond. For A and B, a heavier halogen atom makes the interaction stronger, while for C, the change of interaction energy is not obvious, showing a small dependence on the nature of the X atom in HCCX. A is more stable than B and their difference in stability decreases as X varies from Cl to I. For the F and Cl complexes, A is weaker than C, however, the former is stronger than the latter in the Br and I complexes. The above three types of interactions have been analyzed by means of electron localization function, electron density difference, and energy decomposition, and the results show that they have similar nature and features with conventional interactions. © 2014 Wiley Periodicals, Inc.     

以联席会和竞赛为载体构建实验教学改革交流的新平台——浙江省高校化学化工实验教学中心主任联席会暨化学学科(实验)竞赛10周年回顾

介绍成立浙江省高校化学化工实验教学中心联席会(以下简称:联席会)、举办化学学科(实验)竞赛的背景及发展情况。以联席会和竞赛为载体,建立了全省实验教学研究与改革的交流平台,扩大了实验教学示范中心的影响力和辐射面,推动了实验室建设、课程建设以及人才培养等各项工作,取得了丰硕的教学成果。     

Non-linear determinacy of minimum wave speed for a Lotka-Volterra competition model

For a reaction-diffusion system that serves as a 2-species Lotka-Volterra diffusive competition model, suppose that the corresponding reaction system has one stable boundary equilibrium and one unstable boundary equilibrium. Then it is well known that there exists a positive number c^?, called the minimum wave speed, such that, for each c larger than or equal to c^?, the reaction-diffusion system has a positive traveling wave solution of wave speed c connecting these two equilibria if and only if c?c^?. It has been shown that the minimum wave speed for this system is identical to another important quantity - the asymptotical speed of population spread towards the stable equilibrium. Hence to find the minimum wave speed c^? not only is of the interest in mathematics but is of the importance in application. It has been conjectured that the minimum wave speed can be determined by studying the eigenvalues of the unstable equilibrium, called the linear determinacy. In this paper we will show that the conjecture on the linear determinacy is not true in general.     

Inventory competition for newsvendors under the objective of profit satisficing

Inventory competition for newsvendors (NVs) has been studied extensively under the objective of expected profit maximization which is based on risk neutrality. In this paper, we study this classic problem under the objective of profit satisficing which is based on downside-risk aversion. Consistent with prior literature, we consider two possible scenarios. In the first scenario, each NV’s demand depends on the stocking levels of all NVs other than herself. In this scenario, we show that there is a unique Nash equilibrium where all NVs optimally order as if they were independent. In the second scenario, each NV’s demand depends on the stocking levels of all NVs including herself. We prove the existence of Nash equilibrium for both additive and multiplicative forms of demands. As a special case, we also study symmetrical NVs under the proportional allocation model. We show that at equilibrium, if the number of NVs exceeds a threshold, the market becomes highly competitive.     

以力学竞赛促进基础力学教改的创新与实践

以组织与辅导力学竞赛为契机,促进基础力学教学改革. 着眼于提高学生的力学素养与创新 能力,围绕如何创新基础力学教学新模式,从激发学生学习的热情与动力、改革教学实验、 提升力学课程建设等方面介绍了基于大学生力学竞赛培养力学人才与促进高校基础力学教学 改革的基本做法、实践效果与创新成果.     

2008年中国足球超级联赛成绩与技术统计的因子分析

通过查阅资料,收集、并整理了2008年中超联赛15支队伍210场比赛的技术统计.运用因子分析法对比赛成绩与技术统计的关系进行了研究,命名并分析影响比赛成绩的5个因子.旨在揭示统计指标与比赛成绩的特点与规律,为我国足球运动的理论与训练提供科学依据。     

Strong competition model with non-uniform dispersal in a heterogeneous environment

In this study, a strong competition model was considered between two species in a heterogeneous environment. For a system with two different constant diffusion rates for each competitor, the fast diffuser can be selected evolutionally under suitable assumptions if the competing interaction between the species is strong. We also claim that a strongly interacting competition leads to a more evolutionary selection than that with the same population dynamics if a species moves with a certain non-uniform dispersal. Furthermore, species with a certain non-uniform dispersal have a competitive advantage over linear random diffusers. In addition, a species with highly sensitive dispersal response to the environment may survive. These strongly competitive advantages were demonstrated by investigating the stability of semi-trivial solutions of the system with non-uniform dispersal and comparing it to the conditions of the model with constant diffusion.