Determination of the rheological behavior of epoxy–amine thermosets by dynamic mechanical analysis: Isothermal methods versus nonisothermal methods

The reticulation process of an epoxy resin using an amine as a cure agent was studied at different temperatures and concentrations of the cure agent with dynamic mechanical thermal analysis. The study was performed under both isothermal and nonisothermal conditions, and a temperature–time–transformation diagram was obtained. The measurements from the two modes gave similar results, although the nonisothermal mode required fewer experiments. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1965–1977, 2003     

关于可对称化矩阵的Weyl-Лидский型定理

建立了可对称化矩阵情形下的型定理和与近似不变子空间相关的特征值扰动分析.拓广了W Kahan的相应结果.     

集值函数的广义共轭函数和次微分

该文通过推广实函数的凸共轭函数及其次微分的概念,建立了一类关于集值函数的广义共轭函数及其次微分理论——集值函数的(H,Ω)共轭函数及(H,Ω)次微分理论。这一理论可以用来建立非线性规划问题的一类对偶性原理。     

四个麦芽品质性状的杂种优势和相关分析

本文对四个主要麦芽品质性状—a一淀粉酶活力、麦芽汁粘度、麦芽汁色度和搪化力进行了杂种优势和相关分析.(1)相对优势结果表明，在84个组合次中，呈正向优势的46个，占54.76男，负向优势34个，占40.48男，无显性4个，占4.75男;(2)四个品质性状的中亲优势平均值分别为一6.117、一9.965 40.452和一。.545s a-淀粉酶活力和糖化力的超高亲优势分别为一14.578和一8.201,麦芽汁粘度和色度的超低亲优势分别为5.442和70.455.四个性状杂种优势的变异系数均很大.(3)麦芽汁色度的F，对MP的回归系数(B)和相关系数(r)均达显著水平，分别为。..43和0.50，麦芽汁粘度的相关系数达显著水平，为一。.45,其余均未达显著水平，(4)除麦芽汁色度性状外，另三个性状的中亲优势、超亲优势和特殊配合力的相关均达显著或极显著水平.(5)四个麦芽品质性状间的相关结果表明，仅有a-淀粉酶活力和麦芽汁粘度间呈极显著负相关(r=一0.56').最后，文章根据实验结果，就啤酒大麦麦芽品质改良的遗传育种及其杂种优势应用进行了初步讨论.     

暂态电路的试验设计

在电工电子技术暂态电路的试验设计中，因电路本身响应时间短，用常规仪器很难对其响应的过程进行直接测量。本文结合暂态电路的工作原理及常规仪器的特点，给出三种简单、实用的试验电路设计方法。     

A density functional theory computational study of the role of ligand on the stability of CuI and CuII species associated with ATRP and SET‐LRP

Atom transfer radical polymerization (ATRP) and single electron‐transfer living radical polymerization (SET‐LRP) both utilize copper complexes of various oxidation states with N‐ligands to perform their respective activation and deactivation steps. Herein, we utilize DFT (B3YLP) methods to determine the preferred ligand‐binding geometries for Cu/N‐ligand complexes related to ATRP and SET‐LRP. We find that those ligands capable of achieving tetrahedral complexes with Cu^I and trigonal bipyramidal with axial halide complexes with [Cu^IIX]⁺ have higher energies of stabilization. We were able to correlate calculated preferential stabilization of [Cu^IIX]⁺ with those ligands that perform best in SET‐LRP. A crude calculation of energy of disproportionation revealed that the same preferential binding of [Cu^IIX]⁺ results in increased propensity for disproportionation. Finally, by examining the relative energies of the basic steps of ATRP and SET‐LRP, we were able to rationalize the transition from the ATRP mechanism to the SET‐LRP mechanism as we transition from typical nonpolar ATRP solvents to polar SET‐LRP solvents. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4950–4964, 2007     

奇异矩阵的Krylov方法的误差分析比较

Krylov方法是求解线性方程组Ax=b,A∈CN×N,b∈CN的一种迭代方法,当A非奇异时,已有很好研究.而当A奇异或接近奇异阵时,在一定的假定条件下,Krylov方法的解与范教最小的最小二乘解A+b之间的差是可以估计出来的.     

提高抽送黄河水用泵寿命的重要途径

从保证抽送黄河水用泵（以下简称抽黄泵）的寿命和工作可靠性出发，提出了抽黄泵性能参数选择的原则：限制抽黄泵的单级扬程Ｈ；限制抽黄泵单级扬程Ｈ与转速ｎ的乘积Ｈｎ值。并给出抽黄泵性能参数的Ｈ·ｎ－Ｑ关系曲线和泵的比转速ｎ＿ｓ与单级扬程Ｈ的关系曲线。     

因子分析-导数光谱法测定苯酚和间苯二酚混合物

本文测定了苯酚和间苯二酚混合体系的一阶导数光谱数据,用目标因子分析对这些导数数据进行处理,以探索因子分析在导数光谱中应用的可能性。在不加任何分离的情况下,成功地确定了苯酚和间苯二酚混合体系中的物种数、物种种类及含量。     

Applying Petri-Net-Based Reduction Approach for Verifying the Correctness of Workflow Models

0 IntroductionTobadaseyd’s o nintfhoer mflaotiwonof s ywsotrekmss t hhraovueg hbe tehne doervgealnoipzead-tion rather than based ontasks .Duetothistrend,work-flowand business process technology has been applied tovarious applications such as ERP, groupwares , E-mar-ketplaces , E-business etc . When business processes areapplied to these applications ,business processes are de-fined by process designers and business process instancesare executed by workflowengines or workflow manage-ment sys…