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161.
构造一类求解三种类型偏微分方程的间断Petrov-Galerkin方法.求解的方程分别含有二阶、三阶和四阶偏导数,包括Burgers型方程、KdV型方程和双调和型方程.首先将高阶微分方程转化成为与之等价的一阶微分方程组,再将求解双曲守恒律的间断Petrov-Galerkin方法用于求解微分方程组.该方法具有四阶精度且具有间断Petrov-Galerkin方法的优点.数值实验表明该方法可以达到最优收敛阶而且可以模拟复杂波形相互作用,如孤立子的传播及相互碰撞等. 相似文献
162.
Shouwen Jin Li Liu Daqi Wang Yanlong Feng Jian Zhong Zhou Xiangang Qian Guochun Zhang Xiudong Chu Hongping Zhong Yan Jiang 《Journal of chemical crystallography》2009,39(7):489-493
Abstract Two imidazolyl derived 1,8-naphthyridine compounds (2,7-diimidazolyl-1,8-naphthyridine (a), and 2-benzimidazolyl-5,7-dimethyl-1,8-napthyridine (b)) were synthesized and structurally characterized by X-ray crystallography. The compound a co-crystallizes with one ethanol and two water molecules to give compound 1. Compound 1 crystallizes in the triclinic, space group P-1, with a = 6.943(2) ?, b = 9.009(3) ?, c = 13.760(3) ?, α = 96.793(2)°, β = 97.431(3)°, γ = 107.080(2)°, V = 804.6(4) ?3, Z = 2. Compound 1 forms a 3D interpenetrated network through hydrogen bonds. Compound b co-crystallizes with three and one half water molecules to form 2. Compound 2 crystallizes in the monoclinic, space group C2/c, with a = 24.926(8) ?, b = 10.608(3) ?, c = 16.751(5)?, β = 110.133(4)°, V = 4159(2) ?3, Z = 8. The free water molecules form six-membered rings, these water rings connect the naphthyridine to form one dimensional
chain when viewed from b axis. The naphthyridyl rings in a and b axis are connected through C–H···π, and π–π interactions, due to the weak interactions the compound shows 3D network structure.
Graphical Abstract Due to the weak interactions, the naphthyridine derivatives showed 3D network structure.
相似文献
163.
利用锥上的不动点定理证明了二阶Nuemann特征值问题-u″+Mu=λa(t)f(u(t))m0≤t≤1 u′(0)=u′(1)=0是的正解存在性结果. 相似文献
164.
以飞秒 40 0及 2 66nm激光脉冲结合泵浦 探测飞行时间质谱方法研究了苯S2 态内转换动力学 .40 0nm双光子过程将苯分子激发到S2 电子态 ,布居在S2 电子态的分子由于能级耦合无辐射弛豫到S1电子态 .通过测定C6 H6 +讯号强度随泵浦 探测延迟时间的改变 ,获得苯S2 及S1电子态的衰减寿命分别为 ( 48± 1)fs及 ( 6.5± 0 .2 )ps ,S2 态及S1电子态的消激发机理被认为是相应势能面间的锥形交叉引起的内转换 相似文献
165.
此文首次用ahinitioCID/6—31G法计算了HeH2+(X2Σ+)的平衡键长、离解能和谐性力常数。应用简化的多体项展式法,导出了HeH2+(X2Σ+)的分析势能函数,考察了势能面的主要特征。 相似文献
166.
采用光偏转法研究气体中准分子激光与石墨和铜相互作用产生等离子体羽的特性。用空间和时间分辨的光偏转信号分析了等离子体羽的漂移速度和膨胀速度,并从光偏转信号中测得了物质波前面的激波速度。 相似文献
167.
Energy and electron transfers in photosensitive chitosan 总被引:3,自引:0,他引:3
Novel photosensitive chitosan was synthesized. The modified chitosan contains photoactive anthracene chromophore moieties. Because of the presence of anthracene chromophores, the polymer absorbs light in the UV-vis spectral region. Electronically excited polymeric chromophores could participate in energy and electron transfer processes to the suitable acceptor molecules. The photosensitive chitosan developed herein could could act as an efficient photosensitizer and lead to the application of the environmentally friendly photocatalytic system for an efficient degradation of a wide range of pollutants. 相似文献
168.
X-ray diffraction has been used to study the changes in the surface properties of a montmorillonitic clay through the changes in the basal spacings of montmorillonite (SWy-2) and surfactant-intercalated organoclays. Variation in the d-spacing was found to be a step function of the surfactant concentration. High-resolution thermogravimetric analysis (HRTG) shows that the thermal decomposition of SWy-2-MMTs modified with the surfactant octadecyltrimethylammonium bromide takes place in four steps. A mass-loss step is observed at room temperature and is attributed to dehydration of adsorption water. A second mass-loss step is observed over the temperature range 87.9 to 135.5 degrees C and is also attributed to dehydration of water hydrating metal cations such as Na+. The third mass loss occurs from 178.9 to 384.5 degrees C and is assigned to a loss of surfactant. The fourth mass-loss step is ascribed to the loss of OH units through dehydroxylation over the temperature range 556.0 to 636.4 degrees C. A model is proposed in which, up to 0.4 CEC, a surfactant monolayer is formed between the montmorillonitic clay layers; up to 0.8 CEC, a lateral-bilayer arrangement is formed; and above 1.5 CEC, a pseudotrimolecular layer is formed, with excess surfactant adsorbed on the clay surface. 相似文献
169.
Capillary electrophoretic analysis of cyclodextrins with dynamic fluorescence labeling and detection
The use of 8-anilinonaphthalene-1-sulfonic acid (8,1-ANS) as buffer additive in the capillary electrophoretic separation of cyclodextrins (CDs) was investigated. Better detection sensitivity was obtained for - and γ-CDs than with previously reported capillary electrophoretic methods. Increasing the concentration of 8,1-ANS improved resolution and sensitivities for -, β- and γ-CDs, while decreasing the pH of the background electrolyte can improve sensitivities. Detection limits for -, β- and γ-CDs were determined to be 60, 20 and 7 μM, respectively. The formation constants of CD–8,1-ANS complexes at pH 6 were also measured by capillary electrophoresis. Finally the specificity of amyloglucosidase to CDs was analyzed as a practical application of this method. 相似文献
170.
Hongping Ren 《Journal of organometallic chemistry》2007,692(10):2092-2098
A facile synthesis of o-hydroxyaryl-substituted N-heterocyclic carbene ligands and their complexes with palladium is presented. This kind of salicylaldimine-like NHC ligands expands the class of available NHC ligands for organometallic catalysts. 相似文献