精确Cosserat弹性杆动力学的分析力学方法

以脱氧核糖核酸和工程中的细长结构为背景, 大变形大范围运动的弹性杆动力学受到关注. 将分析力学方法运用到精确Cosserat弹性杆动力学, 旨在为前者拓展新的应用领域, 为后者提供新的研究方法. 基于平面截面假定, 在弯扭基础上再计及拉压和剪切变形形成精确Cosserat弹性杆模型. 用刚体运动的概念描述弹性杆的变形, 导出弹性杆变形和运动的几何关系; 在定义截面虚位移及其变分法则的基础上, 建立用矢量表达的d’Alembert-Lagrange原理, 在线性本构关系下化作分析力学形式, 并导出Lagrange方程和Nielsen方程, 定义正则变量后化作Hamilton正则方程; 对于只在端部受力的弹性杆静力学, 导出了将守恒量预先嵌入的Lagrange方程, 并讨论了其首次积分. 从弹性杆的d’Alembert-Lagrange原理导出积分变分原理, 在线性本构关系下化作Hamilton原理. 形成的分析力学方法使弹性杆的全部动力学方程具有统一的形式, 为弹性杆动力学的对称性和守恒量的研究及其数值计算铺平道路. 关键词： 精确Cosserat弹性杆 分析动力学方法 变分原理 Lagrange方程     

高氧空位浓度对金红石TiO2导电性能影响的第一性原理研究

采用基于密度泛函理论的平面波超软赝势方法研究了 纯的和不同高氧空位浓度金红石型TiO_2-x (x=0, 0.083, 0.125, 0.167, 0.25)超胞的能带结构分布、态密度分布.同时, 采用局域密度近似+U方法调准了带隙.结果表明, 高氧空位浓度越高, 金红石型TiO₂的最小带隙越变窄、电子有效质量越减小, 自由电子浓度越高, 电子迁移率越低、电导率越低.计算结果与实验结果的变化趋势相符合. 关键词： 高氧空位 2')" href="#">金红石型TiO₂ 电导率 第一性原理     

Synthesis of 6,8-dichloroquinolones utilizing new method and evaluation of their antibacterial activities

Several 6,8-dichloroquinolone analogues were synthesized from the key intermediate compound of 2,3,4,5-tetrachlorobenzene carbonyl chloride,which was obtained from the starting material of tetrachlorophthalic anhydride.Their in vitro antibacterial activities were evaluated.As a result of this study,compounds 21c and 21d were twofold more potent than ciprofloxacin (CPFX) and norfloxacin (NFLX) against Staphylococcus aureus-9,and with the same potent as CPFX and NFLX while against Escherichia coli-2,but were less potent than references in against Pseudomonas aeruginosa-17.     

Two new aristolane sesquiterpenes from Laurencia similis

Two new aristolane sesquiterpenes, namely, aristolan-10-ol-9-one and aristolan-8-en-1-one, were isolated from the red alga Laurencia similis. Their structures were established on the basis of various NMR spectroscopic analyses, including 2D NMR techniques (1H-1H COSY, HMQC, HMBC, and NOESY) and HR-FAB-MS.     

Synthesis and NHE1 inhibitory activity of ligustrazine derivatives

A series of novel derivatives of ligustrazine linked with substituted benzoyl guanidine were synthesized. These compounds have not been reported in literature, and their chemical structures were confirmed by IR, 1H NMR and MS. The results of NHE1 inhibitory activity test showed that compounds I2, I3, I4, I6, and I7 possess more potent NHE1 inhibitory activity than cariporide.     

一种城市路灯合理排布的优化设计方法

文章借助于物理模型和数学计算分析，给出了一种优化的城市路灯排列的设计方法．利用该方法优化出的路灯排列方式（如三角型排列），与现在普遍采用的对称排列方式相比，可以在满足人们交通安全和正常工作生活的条件下，达到节省电力能源的效果；或者是在能源耗费相同的条件下，能提供更高、更均匀的照明度．     

ADSORPTION OF DYES ON ACTIVATED CARBON FIBERS

1.INTRODUCTIONDyewastewaterisakindofseriouspollutionsource.InthetraditionaltreatmentmethodsfordyewastewatergenerallytherearefourapproachesincludingelectricchargeneutraliZationofgelparticles,complexation(chelatation),redoxreaction,andbiochemicalcoagulationII~31.Recently,dyewastewaterhasbecomemoreconcentrated,moredifficulttodegradedbiochemically,andmorepoisonous,whichbringsaboutagreatchallengeforwatertreatment.AlthoughtheCOD(chemicaloxygendemand)mayfitthequalitystandardofwastewaterdischar…     

A study on the preparation and characteristics of zeolite membrane PLOT column by in-situ synthesis

Summary The preparation of a zeolite membrane PLOT column by in-situ synthesis is described. The advantages of this new column are discussed. Some analytical applications to alkanes, arenes, esters, alkyl halides and ethers on the zeolite membrane PLOT column compared with those on a coated zeolite PLOT column are reported.     

Synthesis of 2-hydroxy-3-substituted naphthoquinones using the Heck reaction

An efficient Heck coupling of 2-hydroxy-3-iodo-naphthoquinone with a series of electron-deficient alkenes in aqueous solution has been accomplished. The method is characterized by simple conditions and facile work-up to isolate the products in good to excellent yields. The products contain the motif present in several naphthoquinone pigments but with enhanced polarity.     

碱金属原子双光子共振的能级与光谱

双光子共振增强了碱金属原子的非线性极化率，可以观测到多种非线性光学过程产生的非线性光谱，本文分析了有关的能级分布和光谱特点。