One approach to calculating the solvent reorganization energy of intramolecular electron transfer

On the basis of the electromagnetic field theory and the spherical cavity approximation.the expressions of Gibbs free energies under equilibrum and non-equilibrium solvation conditions are obtained by solving the electrostatic potential equations with boundary conditions.The surface charges produces by the orientational polarization of equilibrium solvation are taken fixed in the case of non-equilib-rium situation ,for the slow-response of the orientational polarization to electron transfer of the solvent molecules.A new expression of solvent reorganization energy has been obtained and this method is applied to the electron transfer systems.NO^ /NO,NO2^ ,NO2,and NO2^ /NO,The solvent reorganization energies have been evaluated.     

Explicit solvent model for spectral shift of acrolein and simulation with molecular dynamics

By introducing the concept of spring energy of permanent dipole and taking the conforma-tions of solvent molecules into account,the formulas of electrostatic solvation energy in equilibrium and nonequilibrium are derived from the explicit solvent scheme,with the spatial distribution of the discrete permanent charges and induced dipoles of the sol-vent molecules involved. The energy change of sol-ute due to the variation of wave function from the case of vacuum to that in solution is estimated by treating the solvent effect as external field in the it-eration cycles of the self-consistent field. The ex-pression for spectral shift is deduced and applied to the processes of light absorption and emission in solution. According to the new formulations,the av-eraged solvent electrostatic potential/molecular dy-namics program is modified and adopted to investi-gate the equilibrium solvation energy of water mole-cule and spectral shift of acrolein.     

Synthesis of urchin-like Sn–ZnO–C composite and its enhanced electrochemical performance for lithium-ion batteries

Urchin-like Sn–ZnO–C composite have been successfully prepared by thermal annealing of ZnSn(OH)6precursor in acetylene/argon gas(1/9;v/v).The phase of the urchin-like Sn–ZnO–C has been characterized by X-ray diffraction(XRD)and Raman spectrum.The images of scanning electron microscopy(SEM)and transmission electron microscope(TEM)demonstrate that the Sn–ZnO–C composite with an average of 3 lm in diameter is composed of many core–shell nanowires and carbon nanotubes emanated from the center.The thermal annealing temperature and time have crucial effects on the formation of urchin-like structure and carbon content of the Sn–ZnO–C composites.As an anode for lithium-ion batteries,the urchin-like Sn–ZnO–C composite delivers a discharge capacity of 1,034.5 mAh/g in initial cycle and 571.9 mAh/g reversible discharge capacity after 25 cycles at a current density of 50 mA/g.The superior energy storage properties highlight the urchin-like Sn–ZnO–C composite as a potential alternative anode material in lithium-ion batteries.     

Exhaust gas energy recovery system of pneumatic driving automotive engine

Almost the same quantity to net output work of energy has been carried out and wasted by exhaust gas in typical automotive engine. Recovering the energy from exhaust gas and converting to mechanical energy will dramatically increase the heat efficiency and decrease the fuel consumption. With the increasing demand of fuel conservation, exhaust gas energy recovery technologies have been a hot topic. At present, many researches have been focused on heating or cooling the cab, mechanical energy using, and thermo-electronic converting. Unfortunately, the complicated transmission of mechanical energy using and the depressed efficiency of thermo-electronic converting restrict their widely applying. In this paper, a kind of pneumatic driving automotive engine exhaust gas energy recovery system, in which highly compressed air acts as energy storing and converting carrier, has been established. Pneumatic driving motor can produce moderate speed and high torque output, which is compatible for engine using. The feasibility has been certificated by GT-Power simulation and laboratory testes. The technologies about increasing recovery efficiency have been discussed in detail. The results demonstrated that the in parallel exhaust gas energy recovery system, which is similar to the compound turbo-charger structure can recovery 8 to 10 percent of rated power output. At last, a comprehensive system, which includes Rankine cycle based power wheel cycle unit etc, has been introduced.     

Polythiophene: Synthesis in aqueous medium and controllable morphology

Various morphologies of polythiophene have been designed and successfully prepared by chemical oxidative polymerization in the presence of phase transfer catalyst （PTC） cetyltrimethylammonium bromide （CTAB） in aqueous medium. The morphologies of polythiophene could be controlled in ribbons, fibers and spherical particles by changing the concentrations of reductant, oxidant and phase transfer catalyst. The structure, thermal stability and the conductivity have been characterized, and a mechanism for the transformation of the morphology of polythiophene has been proposed.     

Progress in dynamic study on the triplet excited states and radical ions of DNA and its components

Progress in dynamic study on the triplet excited states and radical ions of DNA and its components is reviewed. It has been found that acetone is the only effective sensitizer for the study of the triplet excited states of DNA components. The transient absorption spectrum of guanyl radical cation resulting from the interaction of triplet acetone and DNA was observed directly, and the original evidence for selective damage of DNA by excited photosensitizer was obtained for -the first time, which offered a new pathway for obtaining the main transient species of selective damage of DNA by photonucleases and illustrating initial oxidation mechanism of DNA via electron transfer.     

Solvent effects on photophysical properties of copper and zinc porphyrins

The photophysics of Zn（tetraphenylporphyrin,TPP）, Zn（tetra-2,4,6-trimethylphenyl porphyrin, TMP）, Zn （tetra-（o-dichlorophenyl） porphyrin, TPPCI8）, Cu（tetraphenylporphyrin,TPP）, Cu（tetra-2,4,6-trimethyl- phenyl porphyrin,TMP）, and Cu（tetra-（o-dichlorophenyl） porphyrin, TPPCIE, TPPCI8） in several solvents have been investigated on steady state and time-resolved spectroscopy. The Cu（TPPCI8 ） is normal and shows no evidence of CT transition in the visible or near UV regions in nonpolar solvent. However, Cu（TPPCI8）shows a blue shift in the absorption spectrum and intramolecular CT bands at absorption spectra in polar solvent, which shows a fluorescence maximum emission at 650 nm and 8.4 ns lifetime. The reason can be attributed to two points. Firstly, the increase of solvent polarity can enlarge outer reorganisational energy, which is favorable to reduce the activation free energy of charger-transfer transition based on Marcus theory of electron transfer. Moreover, the internal heavy-atom effect on Cu（TPPCIE） is encouraging to stabilize the 2T1 state also, which increases the possibility of population to CT band from 2T1 state. This result is in accord with an earlier estimate of a 10 ns lifetime and CT absorption at 640 nm bands for the CT state of Cu （11） octethylporphyrins. Other possible reasons arousing unusual fluorescence like H-bonding, axial ligands, molecular aggregation are excluded.     

Catalytic self-assembly preparation and characterization of carbon nitride nano-tubes by a solvothermal method

A solvothermal reaction of anhydrous CaNaCl3 and sodium using cyclohexane as solvent and NiCI2 as catalyst precursor has been carried out to prepare carbon nitride nanotubes successfully at 230℃ and 1.8 MPa. The carbon nitride nanotubes were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron diffraction (ED), electron energy loss spectrum (EELS) and Raman spectrum.SEM and TEM results indicated that the tubes have a length of 20-30 μm, a uniform outer diameter of about 50-60 nm,an inner diameter of 30-40 nm and are highly ordered assembled as bundles. The EELS measurement indicated that the ratio of N/C was about 1.00. The ED and XRD analyses revealed that the tube may have a new CN crystalline structure. The growth mechanism of nanotubes was discussed.     

Self-assembling Characteristics of Amphiphilic Star Block Copolymers with a Polyelectrolyte Shell

1 Results Amphiphilic block copolymers are capable of forming supramolecular assemblies resembling those observed in nature,such as spherical micelles,worm micelles,and vesicles.Changing the solvent composition,ionic strength or pH of the polymer solution may induce the self-assembly of block copolymers or trigger the transition between the geometries of noncovalent assemblies.In the current work,we have synthesised starlike amphiphilic block copolymers having hydrophobic poly(methyl methacrylate),PMMA,core,and hydrophilic poly(acrylic acid),PAA,shell.The self-assembling characteristics of these polymers have been investigated in aqueous solutions by light scattering and direct visualisation by cryo-transmission electron microscopy (cryoTEM)[1]. Computer simulations along with the theoretical predictions made for the star-like system based on mean-field theory have been used to support the experimental observations[2]. The association of the starlike macromolecules resembles that of charged biopolymers,such as actin,since a balance between attractive and repulsive forces is required for the formation of cylindrical assemblies and can be manipulated by changing the pH or the ionic strength of the solvent[3].     

Numerical study on solid–liquid phase change in paraffin as phase change material for battery thermal management用于电池热管理的石蜡相变材料固液相变的数值模拟

With the large latent heat and low cost, the paraffin has been widely used in battery thermal management(BTM) system to improve the efficiency and cycling life of power battery. The numerical model of paraffin melting in a cavity has been established, and the effects on the solid–liquid phase change process have been investigated for the purpose of enhancing the heat transfer performance of paraffin-based BTM system. The results showed that the location of the heating wall had great effects on the melting process. The paraffin in the cavity melted most quickly when the heating wall located at the bottom. Furthermore, the effects of thermal conductivity and the velocity of the slip wall have been considered. The gradient of liquid fraction increased with the increase in thermal conductivity, and the melting process could be accelerated or delayed by the slip wall with different velocity.     

Single-sphere model for solvent reorganization energy and its application to electron transfer

Electron transfer (ET) is an elementary process in redox reactions, and it has been intensively studied for decades. The ET complexes in which the 7,7,8,8-tetra- cyanoquinodimethane (TCNQ) acts as the electron acceptor, whereas Cu, Ag, etc. as the electro…     

电极上电子转移反应中的重组能的计算

本文为精确计算电极上电子转移反应中的重组能提供了一种新的理论方法。文中三个精确的势能函数可以用实验光谱数据和溶剂化物的热力学数据进行解释。重组能可以根据给出的模型和三个势能函数进行计算,计算出来的活化能和重组能的理论数据同实验结果是一致的。     

金属—苯重组能的计算

基于捕获力场潜能的模型的Ｂａｔｅｓ提出的绝热不变性理论,采用改进了平均偶极矩理论（ＩＡＤＯ理论）,我们计算了过渡金属离子－苯配合物之间的力常数及一系列内氛重组能,讨论了理论计算结果与实验结果之间差别的原因。结果表明该工作有效地改进了前人的工作,取得了与实验光谱标度数据一致的规律性,并与光发射实验结果吻合较好,它避免了因缺乏溶液中可信的振动光谱数据在内氛重组能计算上的困难,通过易得的离子和配体的物理     

外磁场中介观金属环的量子电流和能谱及其量子涨落

针对处于外磁场中的介观金属环系统,假设在电荷空间中具有变换的对称性,通过求解本征值方程给出系统的量子电流、能谱关系;利用最小平移算符的性质等,计算介观金属环中电流和能量的量子涨落.研究介观金属环中量子电流、量子能谱的性质,分析影响量子涨落的因素.结果表明,量子电流、量子能谱不仅与外磁场、介观金属环电参数有关,而且还明显地依赖于电荷的量子化性质.     

M- H/M~ - H 体系重组能的从头算法

基于一种新的从头算法计算了Ｍ－ Ｈ／Ｍ＋ － Ｈ 体系电子转移反应的重组能,对每个反应物进行几何优化． 结果表明：用从头算法计算的双原子分子的键长和振动频率与实验光谱数据吻合较好． 利用精确的重组能Ｇｅｏｒｇｅ＿Ｇｒｉｆｆｉｔｈ＿Ｍａｒｃｕｓ（ＧＧＭ）模型计算得到的重组能数值与实验光谱数据中得到的值相比较,结果显示,在气相状态的电子转移反应中,直接计算重组能的值要比传统的ＧＧＭ 方法准确     

非正则函数组Riemann-Hilbert边值问题

讨论了一般情况下,非正则型函数组Riemann-Hilbert边值问题的求解。对原问题通过引入与正则型问题相同的变换,将问题化成为分别求解相对独立的一个Riemann边值问题和一个Hilbert边值问题;通过引入对角矩阵的方法,将非正则型问题化为正则型,求得一般解;对如何应用Hermite插值多项式的特点、将一般解简化为更为适用的形式作了说明。     

The effect of hydrogen-bond in alcoholic solvent on the solvation ultrafast dynamics of oxazine 750 dye

The ultrafast dynamics of oxazine 750 dye was studied in methanol, ethanol, 1-propanol, 1-butanol solvents using the femtosecond time-resolved stimulated emission pumping fluorescence depletion （FS TR SEP FD） technique. The faster decays on the hundreds of femtosecond time scale and the slower decays on the order of picosecond were found. The intramolecular vibrational redistribution （IVR） and the solute-solvent intermolecular photoinduced electron transfer （ET） should account for the faster decay, while the slower decay is attributable to the diffusive solvent relaxation. The results show that the intermolecular hydrogen-bonding network will hinder the rearrangement of the alcoholic molecules in the solvaUon process and the time constants of the slower diffusive solvent relaxation decays are found to increase with the hydrogen-bonding energy in alcoholic solvents.