湖北绿茶中两种新的没食子酸类衍生物的结构鉴定

用2D NMR技术研究了从绿茶中分离得到的2种新的没食子酸类衍生物,对其¹H和¹³C NMR谱线作了全归属.     

关于几类图的L(3,2,1)-标号问题

图G的L(2，1)-标号是一个从顶点集V(G)到非负整数集的函数f(x)，使得若d(z，y)=1则|f(x)-f(y)|≥2；若d(x，y)=2，则|f(x)-f(y)|≥1。图G的L(2，1)-标号数是λ(G)使得G有的max|f(v)：v∈V(G)|=κ的L(2，1)-标号中的最小数κ。本将L(2，1)-标号问题推广到更一般的情形即L(3，2，1)标号问题，并得到了平面三角剖分图、立体四面体剖分图的λ3(G)的上界。     

Solvent‐dependent structural dynamics of 2(1H)‐pyridinone in light absorbing S4(ππ*) state

The B‐band resonance Raman spectra of 2(1H)‐pyridinone (NHP) in water and acetonitrile were obtained, and their intensity patterns were found to be significantly different. To explore the underlying excited state tautomeric reaction mechanisms of NHP in water and acetonitrile, the vibrational analysis was carried out for NHP, 2(1D)‐pyridinone (NDP), NHP–(H₂O)_n (n = 1, 2) clusters, and NDP–(D₂O)_n (n = 1, 2) clusters on the basis of the FT‐Raman experiments, the B3LYP/6‐311++G(d,p) computations using PCM solvent model, and the normal mode analysis. Good agreements between experimental and theoretically predicted frequencies and intensities in different surrounding environments enabled reliable assignments of Raman bands in both the FT‐Raman and the resonance Raman spectra. The results indicated that most of the B‐band resonance Raman spectra in H₂O was assignable to the fundamental, overtones, and combination bands of about ten vibration modes of ring‐type NHP–(H₂O)₂ cluster, while most of the B‐band resonance Raman spectra in CH₃CN was assigned to the fundamental, overtones, and combination bands of about eight vibration modes of linear‐type NHP–CH₃CN. The solvent effect of the excited state enol‐keto tautomeric reaction mechanisms was explored on the basis of the significant difference in the short‐time structural dynamics of NHP in H₂O and CH₃CN. The inter‐molecular and intra‐molecular ESPT reaction mechanisms were proposed respectively to explain the Franck–Condon region structural dynamics of NHP in H₂O and CH₃CN.Copyright © 2015 John Wiley & Sons, Ltd.     

地震期间应急资源调度方案的优化选取

应急资源的调度是地震救援工作的重点,为解决这个难题,本文构建了以时效性、伤亡性和经济性为三大分量的多目标函数,然后经过无量纲和Delphi加权处理,将其转化为单目标函数,并将其中的决策效用函数看成运筹学中指派问题的效率函数,最后运用匈牙利法计算出最大的目标函数值,从而得出最优的资源调度方案.与其他多目标的应急资源调度方法相比,本文构建的这种算法具有简易、实用的优点,可以说为地震期间应急资源调度方案的优化选取工作提供了一种切实、可行的途径.     

具有老化效应的单机共同工期安排和工件可拒绝排序问题

研究共同工期安排和具有老化效应的单机排序问题。在整个加工过程中,工件的实际加工时间是与其所在位置和工件本身老化率相关的函数,生产商可以通过支付一定的处罚费用而拒绝加工某些工件。鉴于生产过程中出现老化效应,通过采取维修活动来提高生产率。目标是划分接受工件集和拒绝工件集,确定接受工件集中工件的加工次序和维修活动安排的位置,以极小化接受工件的提前、延误、工期与拒绝工件的总处罚费用的加权和。对这一问题,首先将其转化为指派问题并构造了最优多项式时间算法;其次,证明了目标函数满足一定条件下的问题的更一般形式能够在多项式时间内得到最优解;最后,对本文问题的一个特殊情况,设计了具有更低时间复杂度的多项式动态规划算法。     

Normal Coordinate Analysis of 3-Bromo-1,3-Dinitroazetidine

Abstract

The infrared spectrum of 3-bromo-1,3-dinitroazetidine was interpreted with the aid of normal coordinate calculations. A seventy-two parameter modified valence field was used in those calculations, and the observed wave numbers were fit with an average error of 2.5 cm^?1. An assignment of the bands in terms of symmetry coordinates is given. Many of the force constants were transferred to 1-acetyl-3,3-dinitroazetidine to aid in normal coordinate calculations for that compound.     

Fourier Transform 13C NMR Analysis of Some Methaqualone Metabolites

The natural abundance carbon-13 nuclear magnetic resonance spectra of some methaqualone metabolites were recorded using the pulse fourier transform technique. The chemical shift of various carbon resonances have been assigned on the basis of the chemical shift theory, multiplicities observed in SFORD spectrum and comparison with the chemical shifts of the corresponding carbons of methaqualone.     

Vibrational Spectra of 2,2′-Pyridil and 2,2′-Pyridil-18O and Assignment of Infrared and Raman Bands

Abstract

Vibrational spectra of 2,2′-pyridil and 2,2′-pyridil-¹⁸O in the solid state and in solutions have been measured in the Raman (4000–50 cm^?1) and infrared (4000–100 cm^?1). The assignment of the bands observed is performed using the group vibrational concept and isotopic shifts data of the normal modes. The presence of synand anti-phase vibrations of both pyridyl rings is discussed. The results are compared to the corresponding data for some similar molecules.     

How Well Do We Handle the Sample Preparation,FT-ICR Mass Spectrometry Analysis,and Data Treatment of Atmospheric Waters?

FT-ICR MS (Fourier-transform ion cyclotron resonance mass spectrometry) analysis has shown great potential to aid in the understanding of the extremely high molecular diversity of cloud water samples. The main goal of this work was to determine the differences in terms of formula assignment for analytical (i.e., measurement replicates) and experimental replicates of a given cloud water sample. The experimental replicates, obtained by solid phase extraction, were also compared to the results obtained for freeze-dried samples to evaluate whether the presence of salts interferes with the analysis. Two S/N ratios, generally adopted for atmospheric samples, were evaluated, and three different algorithms were used for assignment: DataAnalysis 5.3 (Bruker), Composer (Sierra Analytics), and MFAssignR (Chemical Advanced Resolution Methods Lab). In contrast to other works, we wanted to treat this comparison from the point of view of users, who usually must deal with a simple list of m/z ratios and intensity with limited access to the mass spectrum characteristics. The aim of this study was to establish a methodology for the treatment of atmospheric aqueous samples in light of the comparison of three different software programs, to enhance the possibility of data comparison within samples.     

关于有能力限制的指派问题的一点注记

首先讨论了有能力限制的不平衡指派问题的转化和最优性,并提出了采用最小费用最大流的方法求解该问题.