Distance geometry and molecular dynamics are currently employed in determining molecular structures with interatomic distances from NMR NOESY experiment. Because of the flexibility of peptide, distances obtained from NMR are usually not sufficient to confine its structure. Both distance geometry and molecular dynamics will bias in the conformational space at this circumstance. Constraint Monte Carlo simulated annealing was established to solve this problem. Distance constraints were included into the ECEPP/2 force field by introducing a harmonic energy term. Conformational analysis of a pentapeptide with eight interatomic distances from NMR was carried out as a test. By comparison of the 100 conformers obtained from constraint simulated annealing and the 100 conformers from distance geometry calculation, it was found that constraint simulated annealing can cover the outcomes of distance geometry and at the same time give more con-formers fitting to the experimental data. The result shows that constraint Monte-Carlo simulated annealing is more valid in constructing peptide structures from NMR distances than currently employed methods when no sufficient distances from NMR are available.

The state and dynamic behaviour of the Li+ ions in Li1+2.Ti2-x.Mgx P3O12 fast ionic conductor system have been investigated with 7Li solid-state NMR techniques. Two activation energy of Li+ ions motion in the different temperature range and two mangnetic inequlvalent Li nuclei are indentified from NMR results. The mechanism of Li+ ions transport in this system are discussed based on the temperatures dependence of Li NMR line shape and 7Li nucleus spin-lattice relaxation time T1.

The sulfiding procedures of WO3 supported on 7-Al2O3, TiO2-Al2O3 and carbon were examined by TPS (Temperature-programmed-sulfiding) method. Results show that the number of sulfiding peaks of WO3 increases when the loading of WO3 is raised, it can be elucidated that there exist simultaneously various W spieces on the three different carriers when the loading of WO3 becames higher. Comparing the sulfiding temperature of Wos/Tioz-Al:O3 with that of WO3/7-Al2O3, it is found that the presence of TiO2 covered on Al2O3 surface can make WO3 sulfided at lower temperature when WO3 loading is below one monolayer. When carbon is taken as the carrier, the sulfiding temperature of WOs is greatly decreased, and the phenomenon of carbon carrier being gasified is observed when temperature is higher than 7OoK during our experiment. In addition, a structure model of WO3 carried on TiO2-Al2O3 is suggested in this issue.

The title compounds Co4(CO)8(μ-CO)2 (μ4-PSR) [R=-CH3, -C2H5, -C(CH3)3,-(CHa)4CH3] were synthesized by the reaction of Co2(CO)8 with RSPCl2. They were characterized by IR, 1HNMR, elemental analysis. The crystal and molecular structure of Co4(Co)8(μ-CO)2 (μ4-PSC2H5) has been determined by single crystal diffraction method. Crystal data: monoclinic, space group P21 /c, with a=8-445(3), 6=8.562(3), c= 17.125(6)Å, β=104.26 (3)' 9 V=1200.1Å3, Z=2, Dc=1.937gcm-3. Its molecular structure contains an octahedral Co4P2 skeleton which consists of a rectangular four cobalt atoms core and the Co4 core is capped above and below by two quadruply bridging PSR ligands.

12 mixed-metal, four-nuclear clusters Pt2M2 have been calculated and discussed using DV-Xαmethod of quantum chemistry. We studied their bonding regularity and found out that they may be classified as three types: the first kind of clusters formed from Pt and group metal are the most stable one) and Pt atom as far as possible preserves valence electrons of itself, for the second clusters, platinum mixes with group metal, ⅥB metal make major contribution of charges; in the third clusters, in which Pt and Cu, Ag, or Au present quite low electronic valences, the charges of such systems are mainly suppied by the ligand PPh3. We have also found that the triphenyl phosphine ligand is an electronic adjuster for cluster syntheses and the cyclopentadienyl ligand pushes much charges from VIB metal towards the cluster compounds. The 5d energy bands of Pt will rise or fall if ⅥB or IB metal atom interjects into the platinum c1uster. In this case, adsorption ability on the surface of mixed metal will change remarkbly clearly.

 Codeposition process of conductive particles WC with matrix metal Ni from Watts nickel plating bath was studied- The experimental results show that two-step adsorption model proposed by Guglielmi also applies to the codeposition process of conductive particle WC with matrix metal Ni to form Ni -WC composite coating. Strong adsorption step is the rate controlling step. For the Ni-WC codeposition system, it is found that B < A, K=7.0X 103 and the ratio of loose adsorption coverage to strong adsorption coverage of particles at cathode surface is smaller than that of codeposition systems with non-conductive particles.

Enthalpies of solution of NaBr in aqueous mixtures of n-propanol has been measures over various ranges of compositions at 298.15 K, using high-sensitive calorimeter with isothermal shell. On the bases of the results obtained and our former work for the systems NdCl3, BaCl2, NaCl, NaF, and NaI/n-propanol-water, standred enthalpies of solution of afoementioned salts and enthalpies of solvation of sodium halide in aqueous mixtures of n-propanol were calculated. The dependence of enthapies of sulution and solvation of the electrolytes on the nature of ion, composition and structure of the mixed solvents was discussed.

The interaction between polyacrylamide (PAM) and sodium dodecyl sulfonate (R12SO3Na)-Laurate (R11COONa) mixture in various NaOH concentration and mole ratio n(R12S03Na)/n(R11COONa) have been studied by viscosity and ultraviolet-visible spectroscopy. The reduced viscosity measurements show that PAM/R12SO3Na-R11COONa mixed soutions exhibit viscometric behavior of polyelectro1yte-electro -viscous effect. This phenomenon appears even when the concentration of mixed surfactant is smaller than their CMC. The electro-viscous effect of mixed systems increases with the raise of R11COONa amount and the decrease of the concentration of NaOH. These results indicate the complex of PAM-mixed surfactant was taking shape in solution. It was found from ultraviolet visible spectroscopy that hydrogen bond was formed between PAM and R11COOH. The premicelle formation in surfactant solution is posible as concentration of surfactan is smaller than CMC. Therefore, we guess that interaction between PAM and mixed surfactant occurs due to premicelle of mixed surfactans binding to the macro-molecule of PAM by the bydrogen bond of PAM-R11COOH before the formation of the normal micelle.

The LEPS potential energy surfaces for the interaction of H2-Ni(100) and H2Ni(510) systems were obtained using the pairpotential method. The dissociative adsorption properties for H2 on Ni(100) surface were studied, theoretical results are in agreement with the experimental results.
The role of the step in the dissociative adsorption properties for H2 on Ni(510) step surface is that (1) at the terraces under the step, the direct dissociative paths are increased and the translational activation potential barriers axe decreased obviously, (2) at the terraces above the step and near step edge, the precursor dissociative paths are increased. Thus the active regions for the dissociation and association of H2 are situated near the step.

The thermodynandc properties and the kinetic properties of cyclobutyne are comPuted. On the basis of the rate constants which are computed in this work, the ekist lives of cyclobutyne at chrent temperatuxes are first estimated. The computed results give theoretical evidence for ekistance and analysis of cyclobutyne.

The pure buckminsterfullerene sample was ablated by pulsed laser beam on a home-made apparatus. From the recorded time-of-flight mass spectra, it is found that, like the positive ions, the larger negative carbon cluster ions could also be formed from aggregation of buckminsterfullerene. The sizes of the cluster ions with highest signal intensities among each polymerized group of ions axe less than exact times of 60 and are related to the experimental conditions. The sizes of some cluster boons are odd numbers, so they must have non-fullerene structures.

In this paper, thermograms of eight bacteria and growth curves in exponential phase of growth are presented. Growth rate constants and their temperature dependent non-linear equations axe also established. The optimum growth temperature of these bacteria can be easily calculated from such equations. It is very informative for the study of microorganism growth.

TiO2-Al2O3 binary oxides were prepared by gas-phase deposition of TiCl4 on γ-Al2os support. It was found that TiO2 deposition is formed by the reaction of TiCl4 vapour with OH- group on A12O3 surface. The TiO2 loading increases with the number of gas phase deposition operations and the tetrahedral sites of Al2O3 surface was first covered by TiO2. S1ightly decrease of surface area) pore value and average of pore diameter of TiOz-AlzO3 compared with Al2O3 was observed. In Mo/TiO2-Al2O3 catalysts Mo exists mainly in the form of octahedral and polymer Mo7O2' species, while no tetrahedral Mo species has been observed. The model of Mo/TiO2-Al2O3 catalyst could be imagined as a sandwich of MoO2-TiO2-Al2O3. Due to the weaker interaction between Mo species and A1zoa support in this case more Mo6+ ions in Mo/TiO2-Al2O3 sample are reduced to low valence state comparing with that of Mo/Al2O3 at 5o(f C in H2. The experimental results demonstrate that the HDS and HYD activities of Mo/TiO2-Al2O3 catalysts increase with TiO2 content. It means that the full coverage of Al2O3 surface by TiO2 can improve effectively the catalyst activity of molybdenum catalyst in hydrotreating process.

The interaction between water-soluble copolymer P(AM/AMPS) and various anionic surfactants, and the related changes in microscopic and macroscopic viscosity were comparatively studied by fluorescence probe and viscosimeter. The results obtained show that the associated complex is formed via the hydrophobic chain interaction at a certain concentration, along with a drastic increase in microscopic and macroscopic viscosity. The surfactants with weaker hydrophobicity, such as SDS as SLS forms a relatively loose complex and possesses a lower microscopic and macroscopic viscosity. The other surfactants having a longer hydrocarbon chain and stronger hydrophobicity, such as SBS and SK, display a more tightly packed structure and greater microscopic and macroscopic viscosity. However, as furhter surfactant SBS is added, the further intermolecular association results in change of polymer chain conformation from stretch to coiled state and simultaneously decreases in the macroscopic viscosity.

In a beam-beam scattering experiment the excitation functions of the reactions of alkaline earth metals with some polyatomic halides (M+RX- MX+R) have been studied with Laser Induced Fluorescence (LIF) technique. At the variation range of the collision energies, the excitation functions can be taken as
σR(ET)∝ ET(1 + QMAX/ET)n
where ET and QMAX are the collision energy and the reaction exoergic energy, respectively, and n is a parameter which is correlative to the number of the active vibrational modes in radical R during the reaction processes. Tab1e 2 gives the parameters of the excitation functions for these reactions.

The kinetics of oxidation of ethanolamine by potassium diperiodatocupate (Ⅲ) was studied spectrophotometrically in alkaline medium at 293-2-303.2K. The reaction rate showed first order dependance on Cu(Ⅲ) and positive fractional order dependance on ethanolamine. It was found that the pesudo first-order([EA]. >>[Cu(Ⅲ)].) rate constant kobs increases with the increase of [OH-] and decreases with the increase of [IO-4].There is a negative salt effect of addtion of KNO3. The active species and a plausible mechanism involing free redical have been proposed. All the experimental phenomena can be explaimed by the rate equation derived from the mechanism. The rate constant of the rate-determing step together with the activation paraments have also been evaluated.

A method of preparation of ultrafine CaCO3 particles in ordered systems, as in vesicle and microemulsion, consisting of egg yolk phospholipid and water has been introduced. The size of CaCO3 grain was controlled by the content of egg yolk phospholipid and size of liposoms in the systems. It was found by experiment that vaterite is formed inside the doublle layer vesicles but calcite is formed outside of the vesicles. A discussed of the cause of this difference has been given.

The fluorescence quantum yields Фf and lifetimes τ of 1,5-diphenyl-3 naphthyl-2-pyrazoline were measured in methanol/glycerol and cyclohexane/liquid paraffin mixed systems at 288K. Results indicated that the ratio τ/Фf was found to be viscosity independent and equal to the intrinsic radiative lifetime τo calculated from the integrated absorption spectra. In addition, the process of nonradiative decay of the title compound TPP was discussed.

The aim of the present paper is to use non-isothermal differental scanning calorimentry technique to study the crystallization kinetics of a series of Ti-Ni-P electro brush plating amorphous coating plated using the solution in which the acid concentration is pH3, pH5, pH7, pH9 separately. The result shows the phosphorus composition in the coating increases and the crystallization peak of the DSC curve becomes lower as well as wider and the crystallization activation energy E reduses with the the increase of acid concentration in the solution, so E may indicate the stability of the coatings. The crystallization temperatuer Tc and heat of crystallization ΔH do not change regularly when pH changes. According to the kinetics study, the crystallization mechanism of the amorphous coatings may be expressed by Avrami-Erofeev equation(n=1). the kinetics equation is
dα/dT = Ae-E/RT(1- α)