The adsorption of Na~+ on γ-alumina surface at four coverages of Na_2CO_3 (5%, 10%, 15%, and 20% wt/wt) was characterized by solid-state ~(23)Na and ~(27)Al NMR spectroscopy. The experimental results suggest that two distinct adsorbed species are present on alumina surface: surface species and surface salts. At lower coverages of Na_2CO_3 (5% and 10%), a surface species is predominant, in which the Na~+ cations are associated with the oxygen atoms of γ-alumina. With increasing the loading level to 15%, a second adsorbed species begins to appear which is attributed to the surface salt, Na_2CO_3, deposited on the solid surface. Further adsorption of Na_2CO_3 leads to an increase in the amount of surface salt while the amount of surface species remains unchanged. ~1H-~(27)Al CP/MAS experiments give the evidence that some Na~+ cations in the form of surface species are coordinated with the Br~(‥)onsted acid sites of γ-alumina. This may be the main driving force that improves appreciably the catalytic efficiency of Na_2CO_3/γ-Al_2O_3 catalyst.

Layered double hydroxides (LDHs) pillared with heteropolyoxo-metalate have been synthesized via both restructuring of hydrotalcite-like compounds and direct anion exchange under microwave field. LDHs and their derivatives are both found to be efficiency for alkylation of iso-butane and butene with a higher butene conversion and selectivity towards C_8~o.

The time-of-flight mass spectra of carbon nanotube plasma produced by laser was first investigated in this paper. We found the hemi-spherical tips of carbon nanotube were easily fragmentated and aggregated into fullerenes between Coo arid C_(174) in high laser fluence.

The substituent effect of the 1-1 elimination reaction of hydrogen fluoride from ethyl fluoride have been studied by ab initio method at the HF/3-21G level. The reactants are CH_3CH_2F, CH_3CHF_2, CH_2FCH_2F, CH_3CH_2CH_2F, CH_3CHFCH_3, CH_3CHFCN, CH_2CNCH_2F, CH_2NH_2CH_2F, CH_3CHFNH_2 and their reaction barriers are 369.5, 433.5, 306.9, 365.6, 357.3, 354.1, 383.2, 370.3, 250.3 kJ·mo1~(-1) respectively. It can be concluded that the 1-1 elimination reaction of CH3_CHFNH_2 is the easiest to proceed. This conclusion can be rationalized by its characteristic transition state geometry.

The NiO dispersion phase on three different supports have been studied by EXAFS in combination with XRD quantitative phase analysis. The result of XRD shows the threshold of NiO/γ-Al_2O_3 system is larger than that of NiO/TiO_2 system and the threshold of NiO/SiO_2 system is the least. From the FT functions of EXAFS for samples we can find that in NiO/γ-Al_2O_3 system a part of Ni changes its coordination polyhedra into tetrahedra, the Ni-Ni coordination peaks reduce markedly with the decrease of NiO content in samples. The result of EXAFS fitting and phase isolation shows Ni-Ni coordination number increases with the increase of NiO content in samples of NiO/γ-Al_2O_3 system and reaches a maximum value of 4.0 and remains constant when NiO content reaches the threshold obtained by XRD. It shows the structure of NiO dispersion phase is in better agreement with the NiO monolayer dispersion model than any other models.
In FT functions of EXAFS for samples at thresholds of two systems the Ni-Ni coordination peaks of NiO/TiO_2 system is much lower than those of NiO/γ-Al_2O_3 system. But they are similar when their NiO contents both close to the threshold of NiO/TiO_2 system. It shows that though the dispersion capacity of NiO in NiO/TiO_2 system is less than that in NiO/γ-Al_2O_3 system its dispersion performance is better.
In NiO/SiO_2 system the coordination peaks are similar to those of pure NiO and the Ni-Ni coordination number approaches 12 of the pure NiO. It shows it is difficult for NiO to disperse on the surface of SiO_2. In fact, for the NiO/SiO_2 system the threshold obtained by XRD is beyond the experiment accuracy so there is no threshold for this system.
Therefore above facts indicate that dispersion threshold and reducing of metal-metal coordination number of the dispersion phase is a quite characteristic feature of monolayer dispersion state.

Energy-transfer reaction from metastable CO(a~3П) molecule to CN radical has been studied in a room-temperature flow reactor. The CN (B-X, △v=0, ±1, ±2) violet emission bands were obtained. The △v=0 sequence of CN(B) were analyzed by computer simulation. The vibrational temperature is 3400 K. By using the reference reaction CO(a)+NO, the formation rate constant of CN(B) has been measured, k_(CN)(B)=1.1×10~(-11) cm~3·molecule~(-1)·s~(-1).

The thermal decomposition of 2-nitropropene has been studied by using the quantum chemical method LCAO-MO-AM1. The result obtained indicates that 2-nitropropene may be decomposed via a stepwise process. In the first step, a four-membered ring intermediate (to see the reaction (1) at p.1) can be formed. As for the second step, there are two possible reaction pathways. One of them is to cleavage N—O bond firstly, while another one is to break C—O bond at first. From the energetic point of view, the former one is more favorable. The concerned five-membered ring transition state has not been obtained by geometric optimization.

The EHCO-ASED method has been used to investigate the reaction mechanism and the effect of side group (R) on it for the following thermal polymerization of diacetylenes in solid phase: MDA→PBT→PDA (R=Li, CH_3, F). The calculated results reveal that the energy gaps approximate to zero at the Reaction Coordinate 0.86 for all R, meanwhile, the symmetries of frontier orbitals change, so that the thermal polymerization es smoothly. It is also found that all side groups affect the reaction mechanism and the activation energy of the polymerization very little but give a significant influence on the thermal stability of the products (PDA). All the correspoding reaction systems have been dealt with by using the EHMO-ASED method and taking different number of repeated units (n), and the variations of average unit energy (E_t) of PBT and PDA with the increasing n have been discussed.

FT-IR emission spectroscopy has been used to study the surface structure of V_2O_5/TiO_2 catalyst with V_2O_5 loadings of 0.4%, 2% and 10% wt. prepared by impregnation of TiO_2 in NH_4VO_3 solution. The IR emission spectra were recorded insitu durinbg the course of a calcination of the impregnated catalyst from 100 ℃ to 500 ℃. The ammonium vanadate supported on TiO_2 was found to be decomposition more easily than pure NH_4VO_3 most possibly owing to the chemical interaction between vanadate and TiO_2. For 10%. wt. V_2O_5/TiO_2 catalyst the IR peaks due to V_2O_5 phase appeared as the catalyst was calcined at 200—400 ℃. When the catalyst was calcined at 500 ℃ the peaks of V_2O_5 phase were evidently reduced indicating that the part of V_2O_5 phase decreased and a broad peak ranging from 1050 cm~(-1) to 900 cm~(-1) became prominednt especially after a calcination at 500 ℃. The broad peak was tentatively assigned to the highly dispersed VO_x species which might be the two-dimensional vanadium oxide. This study also demonstrated that FT-IR emission spectroscopy is a very sensitive technique for investigating the surface structure of metal oxide catalyst.

As the starting point of the thermodynamic theories of irreversible processes, local equihbrium assumption is usually believed to be applicable to most physicochemical processes under usual conditions. Based on the Boltzmann equation and the stochastic theory of fluctuations, such apphcabihty of local equilibrium assumption to reaction-diffusion processes is studied. It is found that for reaction-diffusion processes involving nonlinear chemical kinetics the results obtained from the stochastic theory are inconsistent to the local equilibrium assumption.

Tantalum sulfide cluster ions (Ta_nS_m~+, n≤9, m≤30) were produced by direct laser ablation of a mixture of tantalum and sulfur powders and studied by a tandem timeof-flight mass spectrometer. It was found that the most stable tantalum sulfide cluster ions were Ta_mS_(2n+7)~+, (n=1-9). The main dissociation channel of the UV-photolysis (248 nm) of tantalum sulfide cluster ions is sequent S_2 loss. For cluster ions with n≥3, besides the S_2 loss channel, the photolysis yields Ta_3S_4~+, or Ta_4S_6~+, as nucleus was suggested for large tantalum sulfide cluster ions.

Alcohols extremely affect the formation of uniform colloidal particles in the hydrolysis of ferric ions for Fe(NO_3)_3-HNO_3 system. The affecting ability of the alcohols decreases by the order: 2-propanol, ethanol, t-butylalcohol, 1-propanol and n-butanol. The uniform colloidal particles could prepare in the aging solutions containing lower concentration of Fe(NO_3)_3 and higher concentration of HNO_3 in the presence of alcohols comparing with that in the absence of alcohols. The shapes and sizes of the particles formed depend not only on the concentrations of Fe(NO_3)_3 and HNO_3, but also the content of alcohols. In general, lower saturation of precipitating species favours the formation of spherical particles, and high saturation for the elliptic ones.

The surface and micelle property of C_7F_(15)COONa/C_3F_7CH_2OH aqueous solution are investigated by surface tension, conductance, electromotive force methods. The results show that when adding C_3F_7CH_2OH into C_7F_(15)COONa solution the surface activity of C_7F_(15)COONa and the counterion binding degree of micelle can be enhanced.

In this work, the tunneling breakdown of n-InP electrode using large signal current density step has been investigated. The influence of current density on the tunneling breakdown is not obvious, but the light intensities affect the breakdown severely. Some parameters are calculated during breakown and explained.

The title 1:1 adduct, has been prepared and a large single crystal with dimensions of 5 mm×50 mm×20 mm was obtained by slow-cooling method. It produces the green radiation at 532 nm under the irradiation of Nd~3+: YAG laser beam at 1064nm. The crystal structure of this potential non-linear optical material was determined by X-ray diffraction method. The crystal is orthorbombic, space group Pca2_1, with a=2.2701(5) nm, b=0.5852(2) nm, c=0.7815(2) nm, Z=4; final R is 0.054 for 702 observed reflections. The intermolecular hydrogen bonds are formed between the amino and carboxyl groups of glycines, which connect the glycine molecules to form two-dimensional network parallel to the (100) plane, while the intermolecular hydrogen bonds between the carboxyl group of glycine and the carboxyl group of m-nitrobenzoic acid let the latter link to above mentioned two-dimensional network.

The effect of temperature on the viscosity for aluminum stearate/benzene gels either with or without benzoic acid has been investigated. The experimental results show that the McAllister's equation can be used to describe the relation between the viscosity and temperature for these gels. The viscosity of these gels increase with elevation of the temperature and the activation Gibbs functions of the viscous flow are negative, this behavior is contrary to that of the most liquids.

We have studied the relaxation of Na(110) and Na_2O(111) surfaces with LEED, and found that the best agreement between theory and experiment in such a structure, the surface layer distance d=0.291±0.01 nm (contracted 0.34%±0.01 nm) [for Na(110)]; and the three atomic surface layer distances d_1=0.117±0.01 nm (expanded 4.63%±0.01 nm), d_2=0.161±0.01 nm(expanded 0.063%±0.01 nm) and d_3=0.086±0.01 nm (expanded 0.75%±0.01 nm) [for Na_2O(111)].

Quantified resonance theory (QRT) involving the use of weighting has been applied to ionization potential, electron affinity, energy of the lowest π→π~* transiton, charge density and bond order in excited state for odd π hydrocarbon radicals, anions and cations, the QRT results are in remarkable agreement with HMO, the heteroatom effects on these properties obtained by QRT are in full accord with PMO. Moreover QRT gives a simple rule for estimating whether odd nonalternant hydrocarbons containing a 5-or 7-membered ring have NBMO or not.

The enthalpy changes for the binding of two alkaloids with the bioactivity to inhibit monoamine oxidase, harmaline(HL) and harmine(HM) to calf thymus DNA have been determined calorimetrically in a 0.01 mol·L~(-1) piperazine-N、N -bis(2-ethanesulfonic acid) buffer(pH=7.0) at 298.15 K by a MS-80 standard Calvet microcalorimeter. The results are △H_(298)(HL)=-10.7 kJ·mol~(-1), △H_(298)(HM)=-29.6 kJ·mol~(-1) respectively. According to the binding energy and thermokinetic curves from the experiments, the mechanism of intercalationm binding of two alkaloids to DNA has been discussed.

This paper, Using potentiometric method, first reports the oscillating behavior of five amino acids (L-methionine, L-cystine, L-tryptophan, L-serine, L-tyrosine) in a new oscillating system of amino acid-BrO_3~--Mn~(2+)-H_2SO_4-acetone. The effect of many factors on oscillation have been investigated. According to Arrhenius equation, the apparent activation energy of the oscillatary induction period and oscillation period of five oscillating systems are obtained within temperature range of 20～37 ℃.

Using the results of quantum chemistry, thermodynamic and kinetic calculations for this experimentally well studied reaction has been carried out. The adaptability of the computational results of diffrent quantum chemistry schemes (considering electronic correlation or not, and basis size) has been analyzed for the chemical reactivities (thermodynamic functions and kinetic parameters). The calculated results are in od agreement with the experimental ones using the larger basis set and considering electronic correlation, but are bad on the contrary. In addition, a set of exact thermodynamic functions and kinetic parameters has been given.