基于串联两阶段网络DEA模型的供应链规模收益分析

数据包络分析(DEA)是评价供应链系统(Supply chain system)间相对有效性的一种重要的工具,但是传统的DEA不考虑供应链的内部结构,对系统效率评价偏高;而本文所研究两阶段串联供应链系统,考虑把部分中间产品作为最终产品输出,增加额外中间投入的情形.基于所提出的供应链系统结构,本文建立相应的串联结构下的网络DEA模型,并针对所建立模型进行相关理论的研究,给出了串联结构下的生产可能集和规模收益情况判定方法.最后,进行数值实验,以验证我们提出的结论.     

Low Cost, High Efficiency, Gain Flattened L Band EDFA Using FBGs as C Band Seed Generators

A low cost, coolerless 980nm diode pumped, gain flattened L band EDFA with fast transient control, high pump efficiency and gain clamping effect was realized by using FBGs as C band seed generators.     

Crystal Structures of Two Potential Tumor Imaging Agents and Therapeutic Agents Copper（Ⅱ） Ternary Complexes with Salicylidene-tyrosinato Schiff Base and Nitrogen-donor Chelating Lewis Base

The crystal structures of two potential tumor imaging agents and therapeutic agents -copper(Ⅱ) complexes with salicylidene-tyrosinato Schiff base and nitrogen-donor chelating Lewis base, [Cu(sal-tyr)(bipy)] 1 and [Cu(sal-tyr)(phen)]2CH3OH 2 are presented. Our work is helpful to get deep understanding of novel 64Cu tumor imaging agents and therapeutic agents.     

Synthesis,characterization, and micellization of an epoxy‐based amphiphilic diblock copolymer of ϵ‐caprolactone and glycidyl methacrylate by enzymatic ring‐opening polymerization and atom transfer radical polymerization

Amphiphilic diblock copolymer polycaprolactone‐block‐poly(glycidyl methacrylate) (PCL‐b‐PGMA) was synthesized via enzymatic ring‐opening polymerization (eROP) and atom transfer radical polymerization (ATRP). Methanol first initiated eROP of ?‐caprolactone (?‐CL) in the presence of biocatalyst Novozyme‐435 under anhydrous conditions. The resulting monohydroxyl‐terminated polycaprolactone (PCL–OH) was subsequently converted to a bromine‐ended macroinitiator (PCL–Br) for ATRP by esterification with α‐bromopropionyl bromide. PCL‐b‐PGMA diblock copolymers were synthesized in a subsequent ATRP of glycidyl methacrylate (GMA). A kinetic analysis of ATRP indicated a living/controlled radical process. The macromolecular structures were characterized for PCL–OH, PCL–Br, and the block copolymers by means of nuclear magnetic resonance, gel permeation chromatography, and infrared spectroscopy. Differential scanning calorimetry and wide‐angle X‐ray diffraction analyses indicated that the copolymer composition (?‐CL/GMA) had a great influence on the thermal properties. The well‐defined, amphiphilic diblock copolymer PCL‐b‐PGMA self‐assembled into nanoscale micelles in aqueous solutions, as investigated by dynamic light scattering and transmission electron microscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5037–5049, 2007     

原子构成万物是宇宙结构的美 ——原子随笔之二

人类很早就在寻找宇宙万物的组成.古希腊最早的唯物论派从物质世界的内部寻找宇宙万物的本源,认为宇宙万物都由"种子"组成.德谟克利特在这种"种子"思想基础上,提出了宇宙万物是由原子组成的猜想.     

神奇的原子——原子随笔之三

人类虽然在2000多年前就预言了原子的存在，然而可以断言，世界上还没有一个人——无论这个人智商有多高，无论这个人的想象力有多强，能够预言原子的种种神奇．因为在原子的世界里不仅不同于我们熟悉的任何东西，也不同于所能想象的任何事情．物理学家费曼曾说：“它显得又古怪，又神秘．”     

圆外区域求解Helmholtz方程

1引言许多科学和工程计算问题都可以归结为无界区域上的偏微分方程边值问题．而求解椭圆方程边值问题的常用技术是有限元方法,可是对于无界区域,在用有限元方法求解时,往往遇到困难．最简单的办法显然是直接略去区域的无界部分求解,但这样做或者导致过低的计算精度,或者要付出很高的计算代价．边界归化,即将求解偏微分方程边值问题转化为边界积分方程,是求解某些无界区域问题的强有力的手段．自70年代以来,有限元和     

一种新型有机电致微腔结构的双模发射

采用结构Glass／DBR／ITO／NPB／NPB：Alq／Alq／Al制作了有机微腔电致发光器件。将空穴传输材料与发光材料以一定比例混合作为发光层，为了便于对比，在不改变有机层的膜厚的情况下同时制作了传统的异质结微腔器件，发现两种器件的发光光谱有很大不同，器件的复合效率与传统的异质结器件相比也得到了很大提高，这是因为将两种有机材料混合能消除界面势垒，提高器件的复合效率，从而提高了器件的发光性能，实现了微腔双模发射，且两个模式的半峰全宽分别为8nm和12nm。通过进一步优化器件结构可以实现微腔白光发射。