Prediction of the Photofading of Selected Derivatives of 5-(4-X-Phenylazo)-3-Cyano-1-(H or Ethyl)-6-Hydroxy-4-Methyl-2-Pyridone: Theoretical Studies, Comparison of AM1 and PM3 Methods

We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.

基于3-PRC并联机构的锂电池包装机应用

目的针对现有锂电池包装机在包装过程中效率和精度低,极易造成锂电池堵塞、容易卡且包装密封性差等问题,提出基于3-PRC并联机构的包装机,并引入3D打印技术。方法首先建立3-PRC并联机构的3D数学模型,求解运动学方程;其次利用Matlab仿真法和机构的行程约束条件,由控制变量法求得该机构的位置工作空间投影视图;然后利用串级PID控制法,建立包装机的动力学及控制模型,对控制算法进行仿真验证;最后建立包装机仿真模型,并在此基础上进行实物验证。结果 3-PRC并联机构的位置工作空间具有对称的规则形状,且横截面分布均匀。在包装机定点包装过程中,各方向欧拉角变化均控制在±3°以内,各向移动过程实际偏差在±1 mm内,并能自主完成圆周运动。结论 3-PRC并联机构可以满足锂电池包装机的位置工作空间要求,仿真和实物验证结果证明了包装机运动控制的合理性与有效性,有效解决了包装过程中运动精度差的问题,可以实现锂电池包装机的快速精准运行,为该机构在锂电池包装机的进一步优化设计和深度应用3D打印技术奠定了理论基础。

多硝基芳香化合物撞击感度的量子化学研究

采用了ＰＭ３方法对一系列多硝基芳香类化合物进行了几何构型的全优化和平衡几何构型下的电子结构计算，结果表明，对于引发键为Ｃ－ＮＯ２的炸药分子，Ｍｕｌｉｋｅｎ键级顺序与实测的Ｈ５０顺序一致。Ｔｅｔｒｙｌ中引入ＮＨ２后，分子中的－Ｎ（ＣＨ３）（ＮＯ２）基团被活化。

永磁转子偏转式三自由度电机磁场解析建模与分析

永磁多自由度运动电机与常规电机相比,优点突出,有着广阔的应用前景。该文提出一种新型永磁转子偏转式三自由度电机,介绍其基本结构和工作原理,分别利用解析法和三维有限元法对电机磁场进行建模分析,得出气隙磁通密度三维模型,并对电机内部的空间谐波进行分析,得到了气隙磁密径向分量的分布数据。通过两种方法的分析对比,结果表明,解析法计算的气隙磁密径向分量与有限元法结果吻合,计算值误差在3.5%以内,验证了所建立磁场模型的正确性。

田菁胶分子中糖单元的结构研究

用量子化学的MOPAC程序的PM3方法在全局优化中确定了田菁胶大分子糖单元的几何构型和稳定构象 ,计算了该大分子绕两个旋转轴θ、φ旋转的势能面和羟基氧的电荷分布等数据 ,结果表明大分子基团之间不能绕θ、φ轴进行自由旋转 ,糖单元主链和侧链上的羟基均可进行取代反应 ,仅取代基几率分布存在差异 ,计算结果与实验值相吻合。

车用电机冷却系统热仿真及其优化

随着电动汽车驱动电机功率密度不断增加、电机安装位置的狭小,常造成电机工作时内部温升过高。水冷电机的温升不仅取决于电机内部复杂的传热网络,也与冷却介质的流动特性密切相关,而冷却水路结构对于冷却介质的流动特性起关键性作用。针对高功率密度电动车用驱动电机存在严重的温升问题,研究了一种C型环槽水路结构。依据计算流体动力学(CFD)原理,采用有限体积法,对电机水冷系统及电机三维温度场进行了计算分析,得到了水路内流体的流动特性和电机温度场分布。研究表明:在该种水路结构下,各水路支路间流场分布均匀,水路与机壳的耦合传热性能匹配良好。

1-异丙基环己硅烷类液晶化合物的量子化学研究——取代联苯基乙烷系列

AM 1 and PM 3 SCF MO calculation have been performed to obtain molecular geometries of 7 1 isopropyl silacyclohexane based liquid crystal compounds biphenyl ethane series by energy gradient completed optimization.For all optimized configurations,there is no imaginary frequency in vibrational analysis.The stable configuration,electronic structure,and some molecular properties of title compounds(heat of formation,dipole moment and energy level of frontal molecule orbital,etc) are frist reported.The calculated results are fully discussed with rspect to the organic structure theory.

1-苯基-4 -乙基( 2′-对取代苯基 )环己硅烷类液晶化合物的量子化学研究

运用AM1和PM3两种SCF-MO方法,通过能量梯度全优化计算,给出4种1-苯基-4-乙基(2′-对取代苯基)环已硅烷类液晶化合物的稳定几何构型,电子结构和分子的基本性质(生成热,偶极矩等),联系有机电子结构理论进行了细致的讨论。

CADD法在降血脂药物研究中的应用

目的:利用计算机辅助新药设计(Computer Aided Drug Design,CADD)技术中的受体图像法,对不同类型降血脂药物的化学结构及甘草次酸类的降血脂药效结构进行模型化研究,并初步探讨甘草次酸类的降血脂药理作用机制。方法:利用计算机程序EMO(分子力学程序)和GEOMOS(量子力学)以及Semi-empirical PM3方法,对4种不同类型的32个具有降血脂活性的分子进行分析。通过分子能量的降低和空间结构的优化处理,测定和计算这些分子的有关几何性、电性和能量参数。然后对优化后分子进行类型内重叠和有关参数的类型间对比观察,预测各类分子的共同药效结构和功能基刚。分了重叠的可行性用参数RMS(Root Meam Square)进行判断。结果:分别获得32个降血脂活性分子的4种不同特征的药效基本结构图像,并发现甘草酸类(如18β-甘草次酸)与苯氧乙酸类(fibrates)分子的优化空间构型中,存在类似的特定结构片段,相应原子和原子团的电荷密度分布(netchrges)、3个电荷中心分布及其相间距离具有可观的相似性。说明在甘草酸类的优化空间结构上可能具有与笨氧乙酸类药物类似的药效结构片段存在,甘草次酸及18-脱氢甘草次酸的铵盐降低71％的甘油三酯和51％胆固醇浓度。结论:甘草次酸类可能具有与苯氧乙酸类类似的降血脂作用机理。

The Activity and Theoretical Interpretation of Role of Trimethyl Phosphite Modified HZSM-5 Zeolite

The catalytic activity of trimethyl phosphite modified HZSM-5 zeolite and un-modified HZSM-5zeolite treated with 100% steam at 673,773,873,973 and 1073K, respectively, were investigated using heptanecracking as a probe reaction. The results showed that the heptane conversion of both trimethyl phosphitetreated samples and un-phosphated samples decreased with an increase in treating temperature, but trimethylphosphite modified samples showed higher activity in comparison with the un-modified samples, which weresteam-treated at a higher temperature. The results were firstly elucidated by the model cluster method andcomputational quantum chemistry method. Full optimization and frequency analysis of all cluster model havebeen carried out using the Gaussian 94 software-package with the PM 3 semi-empirical method performed onsmall cluster models. The computational results showed that the dealumination of trimethyl phosphite modi-fied zeolite model cluster was more difficult than that of un-modified zeolite model cluster when they weretreated with steam while investigating the heat of reaction.

Research of Inclusion Complexation of 4,4'-Thiodiphenol Effected by β-Cyclodextrin in Aqueous Solutions and the Effect on Photodegradation

The inclusion behavior of 4, 4＇ -Thiodiphenol （TDP）, a typical bisphenol and endocrine disruptor, reacts with β-cyclodextrin （β-CD） in aqueous solutions has been investigated by means of UV absorption spectrum and quantum-chemical calculation with Gaussian 98 software. The results show that the inclusion behavior of TDP is quite different in acidic solutions （pH 5.9） from that in alkaline solutions （pH 10.0）. This behavior difference is attributed to the different formula structures in aqueous solutions at acidic and alkaline pH values that are demonstrated by quantum- chemical modeling and calculation. TDP forms a 1 ： 1 fl-CD inclusion complex in aqueous solutions. The equiiibrium constant K was calculated to be 553.49 L/mol at pH 5.9 and 1 318.20 L/mol at pH 10.0 respectively for the inclusion complex reaction by using the modified Benesi-Heldbrand equation. After inclusion TDP＇s structure is changed especially at the inclusion part with the bond order becoming larger, which results in inhibitive photodegradation during direct photooxidation and H2O2 assisted photooxidation.

Quantum Chemical Study on the Thermolysis of Dicyanofuroxan

AM1 and PM3 methods using the unrestricted Hartree-Fock (UHF) calculations have been applied to study the thermolysis of dicyanofuroxan. The results obtained show that the reaction proceeds to product through a two-step pathway where the second one is the rate-determining step.

Semiempirical prediction of the hyperpolarizabilities for cyanovinyl-substituted donor-acceptor molecules

We present here a systematically theoretical study on the nonlinearities and their structure-property relationship of cyanovinyl-substituted donor-acceptor molecules by virtue of semiempirical PM3/AM1-FF approach. Good consistency between measured and calculated hyperpolarizabilities is obtained. Results show that conformation has a significant effect on hyperpolarizabilities. The torsion angle change between two conjugated parts of the molecular systems can substantially alter the nonlinearities. The total amount of charge transfer difference from donor to acceptor has been introduced to understand the microscopic nature of the nonlinear optical properties for the title molecules. General guidelines may be sought out in the search of molecules with large values of beta. Some molecules with large molecular hyperpolarizabilities can be predicted by the optimization for the longer pi-electron systems with both acceptor and donor groups.