邻、间、对-氯苯甲酸钠的NMR(1H,13C)和振动光谱

研究了邻、间、对 -氯苯甲酸钠并记录了这些化合物的 NMR和振动光谱。用能量合适的分子做了单点计算 ,确立了氯和钠对分子中电荷分布的影响 ,并对邻、间、对氯苯甲酸钠分别与苯甲酸钠以及邻、间、对氯苯甲酸做了比较。从各种不同的方法中得出的结论是相同的 ,且表明氯和钠影响了苯甲酸的芳香体系 ,氯和钠的影响特征取决于氯在环上的位置 ,并在碳原子上计算的形式电荷和它的化学位移之间提出相关性。     

Theoretical Study of the Photochemical Reaction Mechanism of Bicyclo [4.1.0 ] heptane

IntroductionPhotochemical reactions, which involve a three-membered ring, have been of great interest to experi-mental photochemists[1—10]. A main reason for thisphenomenon is that the cyclopropane ring exhibits somereaction characteristics of double bon…     

2-(2′-羟基苯基)间氮杂硫茚激发态质子转移反应的理论研究

人们早就认识到质子转移互变异构反应的存在。近年来,发现的激发态分子内质子转移反应更引入注目,因为它有重大的应用前景,如     

硝酸甲酯分子间相互作用的DFT和ab initio比较

用密度泛函理论(DFT)和从头算(ab initio)方法,分别在B3LYP/6 31G和HF/6 31G水平上求得硝酸甲酯三种二聚体的全优化几何构型和电子结构,并用6 311G和6 311＋＋G基组进行总能量计算.对HF/6 31G计算结果进行MP4SDTQ电子相关校正.在各基组下均进行基组叠加误差(BSSE)和零点能(ZPE)校正求得结合能.对6 31G优化构型作振动分析并基于统计热力学求得200～600 K温度下单体和二聚体的热力学性质.详细比较两种方法的相应计算结果,发现DFT求得的分子间距离较短,分子内键长较长,所得结合能均小于相应ab initio计算值.     

RATE OF INTRA-MOLECULAR CONTACT FORMATION IN SHORT TWO-DIMENSIONAL COMPACT POLYMERS CHAINS

It is important to know the rate of intra-molecular contact formation in proteins in order to understand how proteins fold clearly. Here we investigate the rate of intra-molecular contact formation in short two-dimensional compact polymer chains by calculating the probability distribution p(r) of end-to-end distance r using the enumeration calculation method and HP model on two-dimensional square lattice. The probability distribution of end-to-end distance p(r) of short two-dimensional compact polymers chains may consist of two parts, i.e. p(r) = p1(r) p2(r), where p1(r) and p2(r) are different for small r. The rate of contact formation decreases monotonically with the number of bonds N, and the rate approximately conforms to the scaling relation of k(N) ∝ N-α. Here the value of α increases with the contact radius a and it also depends on the percentage of H (hydrophobic) residues in the sequences of compact chains and the energy parameters of εHH, εHP and εPP . Some comparisons of theoretical predictions with experimental results are also made. This investigation may help us to understand the protein folding.     

聚合物异核交叉弛豫及二维NOE谱

The heteronuclear cross-relaxation rates in polymers were determined by selective and conventional ~(13)C spin-lattice relaxation experiments, the proton-carbon distances were calculated by the theoretical formula, and two-dimensional NOE spectra of the polymers were also measured. The results showed that (1) the measured proton-carbon distances coincide with the distances from molecular models, (2) there is the observable dipolar cross-relaxation effect between the quaternary carbons and their neighboring protons, and (3) the optimum mixing times depend on the relaxation properties of the proton and carbon.     

Interlayer Energy Transfer from Naphthalene to Anthracene Chromophores Organized in Langmuir—Blodgett Films

Interlayer energy transfer between 2,3-naphthol-10-hexadecylaza-15-crown-5(NC16) and N-[1-(9-methoxyanthryl)] decylaza-15-crown-5(A10C) within multilayer Langmuir-Blodgett films has been studied by steady-state fluorescence spectra. The donor and acceptor could be separated precisely by inserting stearic acid (SA) spacers. The efficiency of the energy transfer increases with the decrease in the donor-acceptor distance by a quadratic manner, suggesting the donor excitations are delocalized in the layer.     

HCN(HNC)与NH3, H2O和HF分子间相互作用的理论研究

在MP2/aug-cc-pVTZ水平上, 对HCN(HNC)与NH3, H2O和HF分子间可能存在的氢键型复合物进行了全自由度能量梯度优化, 通过在相同水平上的频率验证分析发现了稳定的分子间相互作用形式是HCN(HNC)作为质子供体或作为质子受体形成的复合物. 基组重叠误差对总相互作用能的影响均小于3.34 kJ/mol. 通过自然键轨道(NBO)分析, 研究了单体和复合物中的原子电荷和电荷转移对分子间相互作用的影响. 对称性匹配微扰理论(SAPT, Symmetry Adapted Perturbation Theory)能量分解结果表明, 在分子间相互作用中, 静电作用与诱导作用占主导地位, 而诱导作用与复合物的电荷转移之间具有良好的正相关性.     

加工误差对气体静压径向轴承的影响

建立了一种考虑影响气膜厚度误差、圆度和圆柱度误差的气膜厚度分布综合表达式,考虑加工误差对气体静压径向轴承的影响,进行了气体润滑有限元分析.分析表明:圆度和圆柱度误差对轴承的承载能力影响不大;气膜厚度误差为平均气膜厚度的5%时,承载能力变化约为10%.     

论孙诒让的《墨子间诂》在墨学复活与勃兴中的作用

孙诒让的《墨子间诂》被王焕镳誉之为“墨学研究中的旷代之作”，又被罗检秋称为“墨学发展史上的一个重要里程碑”。它继承吸取了20世纪以前墨学研究的成果，基本恢复了《墨子》文本的真实面目，为墨学思想的研究和现代价值的挖掘铺平了道路，扫清了障碍，促进五四时期墨学科学价值的被发现和平民学说、逻辑价值的确立，以至引来20世纪30至60年代墨学研究的全面丰收，最终促成墨学的伟大复兴。