High silica mordenites with Si/Al ratios in the range of 6-15 were prepared by acid leaching, steaming plus acid leaching and isomorphous substitution with (NH_4)_2SiF_6 methods. The relative crystallinity, hydroxyl nest mole fraction, unit cell parameters, infrared asymmetric stretch frequency, thermal and hydrothermal stability, surface acidity and catalytic activities of the mordenites were investigated with various techniques. It has been found that the properties of the mordenites depend strongly on the preparation methods. Samples prepared with various dealumination procedures show significant difference in many aspects. These differences were described in detail and explained in relation to structural changes of the zeolites.

A series of La_(2-x)Sr_xNiO_4(0.0≤x≤1.0) oxides with the tetragonal K_2NiF_4 structure were prepared. The cell parameters were measured by powder X-ray diffraction (XRD) technique; the reducibility was determined by temperature programmed reduction(TPR). Results show that the changing orders of the highest reducing peak temperature with composition(x) contrast to that of cell parameter a, but agree with that of c. The reducing mechanism for La_(1.7)Sr_(0.3)NiO_4 was investigated by TPR and XRD technique. We found that the first two reducing peaks in TPR profile correspond mainly to the reducing process from Ni~(3+) ion to Ni~(2+). This point was also identified by the calculation of axial ratio indirectly; therefore the highest reducing peak is the structural destroying peak.

The α-Fe_2O_3/NaY zeolite samples were prepared by impregnating NaY zeolite with ammonium ferrioxalate solution and calcining at high temperature. The maximum dispersion amount of α-Fe_2O_3 on NaY zeolite measured with XRD quantitative phase analysis is 0.060 gα-Fe_2O_3/gNaY, which is only 5.5% of the monolayer capacity of α-Fe_2O_3 on NaY according to a close-packed monolayer model. For the first time positron lifetime spectroscopy has been used to detect the dispersion amount of oxide on zeolite. The maximum dispersion amount of α-Fe_2O_3 obtained is fully consistent with that obtained from XRD phase analysis. TPR spectra of the samples show that the reduction of α-Fe_2O_3 on the zeolite consists of two steps, α-Fe_2O_3 is first reduced to Fe_2O_3 at low temperature and then to the metal at higher temperature. Both reduction reactions are ingibited by the strong interaction of the dispersed α-Fe_2O_3 phase with the zeolite.

本文研究了氧、温度和4-甲基-4-苯基-2-戊酮(Mpp)对乙醇辐解的影响。Mpp在实验使用的浓度范围内对乙醛的G值没有影响, G(2,3-丁二醇)值随Mpp浓度增加而下降, 最后达0.9恒值。使用Mpp求得原初过程形成的G_(H_2)=1.9, 动力学处理求得G_H=2.4, k_(12)/k_(11)=(11.9±1.8)×10~3。
实验证明Mpp清除了体系中的H原子, 抑制了CH_3CHOH自由基的形成, 从而抑制了2,3-丁二醇的生成, 但不影响乙醛的产额。这一研究否定了传统文献所述的在γ辐解乙醇时相当量的羟乙基自由基歧化反应生成乙醛。
本文还对乙醇γ辐解机理进行了讨论, 并求得了乙醇辐解的物料平衡。

MINDO/3 MO method has been used to study the mechanism of thermolysis of nitroguanidine. The geometric structures of the transition states are optimized by Powell's method, and confirmed by vibrational frequency analysis. The reaction pathways of the thermolysis have been traced by intrinsic reaction coordinate (IRC) proposed by Fukui. Our results show that there are two pathways for this thermal decomposition reaction (pathway Ⅰ giving rise to products. N_2O, H_2O and H_2NCN; pathway Ⅱ giving rise to products: N_2O, NH_3 and HNCO). They coexist and compete each other.

The self-association of isomeric butanols in carbon tetrachloride, n-heptane, benzene and 1,2-dichloroethane has been studied by infrared sprectrometry in the range of 3800-3000 cm~(-1). It has been found that the area ratios of polymer band to monomer band are related to the characteristics of the solutes and solvents, and the plots of the ratios against mass percent of the alcohol show good linear relation in the measured concentration range. The IR data have also been treated by use of 1-n (cyclic) association models. According to the results obtained, branched chain causes a decrease in some extent of the self-association. In addition, the specific interaction between isomeric butanols and benzene or 1,2-dichloroethane leads to much less self-association of butanols. In diluted solutions, butanol molecules mainly exist in the form of monomer-dimer in benzene and 1,2-dichloroethane, and of monomer-trimer in carbon tetrachloride. In heptane, however, the monomer-tetramer for n-butanol and the monomer-trimer for the other butanols may be the best models accounting for the IR data.

Differential scanning calorimetry was used to investigate the thermal denaturation of the proteinase K (EC 3.4.21.14) in the temperature range from 310 to 450 K. The influence of hydration and pH upon the thermal denaturation was studied in the range of total water content from 0.048 to 4.39 g H_2O/g dry enzyme and in the pH range from 3.29 to 8.49, respectively. The dependence of the denaturational temperature T_d, the specific enthalpy of denaturation ΔH_d and the maximum of excess apparent specific heat C_ex~(max) upon the degree of hydration h and the pH of the buffer is presented respectively. The relationship between the denaturational temperature T_d and the water content is of the Flory-Garrett's type. Besides this, the thermodynamic characteristics of the thermal denaturation of proteinase K are different from those reported of globular proteins, double-stranded coiled-coils and triple-stranded coiled-coils. The influence of primary hydration water upon the thermodynamic parameters of the thermal denaturation is the greatest. The external variable, the pH of the buffer used to dissolve the enzyme influences its thermostability to some extent.

Excess volumes have been measured by means of a continuous dilution dilatometer or a vibrational tube densimeter for both tetrachloromethane and trichloromethane+N,N-dimethylformamide (DMF), +N,N-dimethylacetamide (DMA), +N-methylpyrrolidone(NMP), +γ-butyroIactone(γ-BL) , +dimethysulfoxide(DMSO), at 298.15 K V~E values are negative over the entire range of composition for all systems except (trichloromethane + dimethylsulfoxide) which exhibits a sigmoid curve with negative values in the trichloromethane rich region. |V_(min)~E| values of the two series decrease in the order NMP>γ-BL>DMF≈DMA?DMSO. The results are interpreted in terms of forming charge-transfer complexes between tetrachloromethane and Lewis bases, and forming hydrogen-bonding associations between trichloromethane and Lewis bases respectively.

In previous reports the ternary system Na_2SO_4-CuSO_4-H_2O was investigated by osmotic coefficient and solubility work. This paper reports the determenations of the mean activity coefficients of Na_2SO_4 in the ternary system at 25 ℃ and ionic strength 1.0 and 2.0 by emf method using a Na sensitive glass electrode vs. Hg-Hg_2SO_4 electrodes.
The Hg-Hg_2SO_4 electrodes were prepared in our laboratory and performance tests for the electrode pair were carried out. Linear near-Nernst response and good reproducibility and stability were observed.
Pitzer's recent equations were used to derived...

The electronic structure and chemical bonding of the five coordinate iron clusters [Fe(XCHCHS)_2]_2~n-[X=O, (Ⅰ); X=S, (Ⅱ); n=2, 3, 4] and their monomers have been studied. The calculated data of the quadrupole splitting and chemical isomer shift are in good agreement with those of experiments.The multiplet of the iron in the oxidized ground state of cluster(Ⅰ) is 6, while that of (Ⅱ) is 4, in accordance with the experimental results. The calculation result shows that the oxidation-reduction process in fact takes place on iron, but the electrons gained or lost transfer to the ligand atoms through charge relaxation. The formation of these clusters can be considered as dimerization of two fragments through interaction of their orbitals in the frontier region. An explanation about the configuration difference between (I) and (II) is proposed.

FT-IR transmission spectra of the 3—11 monolayer Langmu ir-Blodgett(LB) films of stearic acid, have been observed compared with FT-IR ATR spectra. As an easily feasible technique, transmission method can offer supplementery information to the ATR one. The intensity ratios between the vibrational bands obtained by the two methods give the orientation aspect of molecular fregments of complecated LB films.

On the basis of the data of single crystal structure analysis, the thermal motion analysis for the crystal molecules of N-phenylphthalimide (Ⅰ) and 2-phenylquinoxaline (Ⅱ) was carried out. It is shown that in solid state the molecule of compound I behaves dynamicaly as a rigid molecule and an intramolecular vibration of the substitued pheny group with <ω~2>=53(25) deg·~2 around C(8)—C(9) should be included in the molecular thermal motion of compound Ⅱ .

The stability constants of binary complex compounds of nickel (Ⅱ) with Lproline, L-valine, α-aminoisobutyric acid and oxalate were determined at 25.0±0.1 ℃, Ⅰ=0.1 mol·dm~(-3) (KNO_3) by pH method. The heats of formation of these binary systems and the heat of protonation of oxalate were determined by calorimetry under the same conditions. The fact that the heat effect of protonation of oxalate was found to be endothermic can be interpreted on account of the existence of seven membered ring of oxalate formed in aqueous solution through hydrogen bonds with water molecule.

The resonance Raman spectra of phenothiazine radical cation, phenothiazine dication and phenoxazine dication have been recorded, which have been formed by chemical oxidation of their parent compounds with Br_2 or Pb(Ac)_4. The bands of CNC and CSC skeletal deformations show the most enhancement and large positive shifts from the corresponding parent after one or two electrons are subtracted from phenothiazine. The number of bands in ring C=C stretching frequency range are increased obviously in the spectrum of phenothiazine dication. The spectral data reveal that the degree of fold along the S—N axis vanishes and a greater aromatic resonance structure comes into being with the loss of two electrons in phenothiazine. The spectrum of phenoxazine dication is more similar to that of its parent, which shows that the loss of electrons in phenoxazine leads to less structureal change compared with phenothiazine.

In order to investigate the influences of specific salt effect of added electrolyte on the classic buffer experiments for distinguishing general and specific acid or base catalysis, the rate constants of the hydrolysis of benzaldehyde di-ter-butyl acetal, triethyl orthobenzoate and N-p-methoxybenzyli-denepyrrolidinium ion in acetate buffers were measured under various conditions. It is found that, for a given reaction, the presence or absence of specific effect of an added salt depends mainly on the ionic stregth and solvent of the buffer solution. In buffers of low ionic strength, e.g. 0.1 mol·L~(-1), using water or mixed solvents containing a small fraction of organic constituent, specific salt effect can be eliminated or considerably reduced and the classic diagnostic buffer experiments can be satisfactory.

A twin, differential, high-temperature calorimeter for the measuremens of enthalpies of formation and transformation in solid alloys has been developed. This apparatus works at temperature up to 1500 K. Its sensitivity and reliability are proved by measuring the heats of transformation of α-to γ-phase in iron. The experimental results are in considerable agreement with those in the published literature.
The calorimeter was used to determine the heats of formation of eight alloy compositions, comprising of σ-and γ-phase, of Fe-Ni-V system. These data have not been measured before. The results show that the enthalpies of Fe-Ni-V solid alloys are negative and tend to decrease generally while the composition of alloy varies from Fe-V side to Ni-V side.

The DNMR Spectra of the intramolecular processes occurring in Mg-, Ca-, Sr-and Ba-1,2-propylenediamine-tetraacetic acids(1,2-PDTA) are reported in this paper. The relative activation parameters have been obtained by performing computer line shape analysis. The experimental results show that the rates of the lone pair inversion of the two nitrogen atoms in these complexes are different, but their activation energies are similar. The nitrogen inversion process of these complexes belongs to twist mechanism through a trigonal prismatic intermediate.

This paper describes the DSC study of 4-trifluorocoumarin derivatives, C_(481), C_(485), C_(500) and C_(480), providing their DSC thermograms and thermodynamic parameters during the phase transitions of these compounds. Singlemelting peaks were observed on DSC thermogram respectively.Experimental results show the existence of certain correlations between the melting point, heat of fusion and molecular structure for this series of compounds.

The surface area and crystal hibit of an AgBr dispersion were determined by a in situ method. In this method, the difference of the absorption spectra of an cationic cyanine dye Ⅰ in adsorption and solution state was used for the measurement of AgBr surface area. It was 17.1 m~2/g AgBr. And the crystal habit was determined hased upon the absorption spectra of an other two cyanine dyes (Ⅱ and Ⅲ) in adsorption state. It showed a cubic crystal.

It was found by means of the small angle X-ray scattering (SAXS),that layer distance of the liquid-crystal system consisting of egg yolk phospholipid (PC) and 5% water changes with the addition of benzene,methylbenzene or chlorobenzene. From this experiment it can be seen that layer distance in 5% H_2O-PC system changes alternatively as the benzene content is increased. It is considered that Water-PC and Benzene-PC bimolecular double layers are formed. As chlorobenzene content is increased, the system is disordered easily. This phenomenon can be explained by the ability of the polar groups and hydro-carbon chain tail of the egg yolk phospholipid being attracted by molecules of chlorobenzene.

This paper describs the structural character of liquid-crystal of 5%H_2O-egg yolk phospholipid (PC) containing in avarious salt's solution, the layer distance was determined by means of SAXS method. Experimental results show that the layer distance of liquid crystal phase is increased in the 5%H_2O-PC system as the amount of solution of NaCl or KCl is increased. But on the addition of Na_2CO_3 or K_2CO_3 solution into the 5%H_2O-PC system the layer distance of liquid-crystal phase is held constant. It is considered that Na_2CO_3 or K_2CO_3, might be hydrolyzed producing OH~- ions, so that the latter could stablize the interfacial potential between water and egg yolk phospholipid. Absence of this behavior for solution of NaCl or KCl might be due to NaCl and KCl are salts which formed by strong acids and strong bases.

Solubilities of nitrogen in binary mixtures of n-octane and n-heptane have been measured at temperatures from 20 to 70 ℃ and pressures up to 130 atm using a precision gas-liquid solubility apparatus. Experimental results can be expressed by the following equation
Inx_(N_2)=A+BP_(N_2)+CP_(N_2)~2+DInP
From the results obtained, the partial molar volume of dissolved nitrogen and the Henry's Law constants have also been calculated.

Pulse-reacting experiments of gaseous CO with catalyst surface oxygen and gaseous O_2 with reduced catalyst surface were designed in order to measure the activation energy of oxygen offering and the activation energy of oxygen reproducing on the catalyst surface. By the separate measurement of these two kinds of activation energy, the difference in behavior of Pt/HM and Pd/HM catalysts was explained.
The activation energy of oxygen offering on Pt/HM is lower than that on Pd/HM, but the oxygen reproducing activation energy on Pt/HM is higher than that on Pd/HM.

The homogenous gas phase pyrolysis of ethyl acetamide is studied by MINDO/3 molecular orbital method.The results show that the major process proceeds via a six membered ring transition state (TS), but the four membered ring TS is also feasible, which is not accessible in the gas phase pyrolysis of esters. A detail analysis of Intrinsic Reaction Coordinate(IRC) is used to elucidate the reaction mechanism. The results also reveal that the change of activation energy in the polar solvent is not evident, in other words, the catalysis by carboxylic acid is not marked for the gas phase pyrolysis of ethyl acetamide.

We have reported the structure of β-cyanoethyf-a-ferrocenylfluorobenzyl ether. Present study is concerned with the crystal and molecular structures of serious β-cyanoethyl-α-ferrocenylhalogenbenzyl ethers (C_5H_5FeC_5H_4CH (OCH_2CH_2CN)C_6H_4X) (X = F, Cl, Br, I). All crystals were solved with direct method and fourier synthesis. The differences of the structures caused by the different halogen atoms are discussed.
The results have shown there are two types of molecular configuration. A for X=F and B for X=Cl, Br, I.

In the present investigation the theory and method to describe the MO's bonding ability with the Hellmann-Feynman electrostatic force are presented, the MO's bonding effects on a certain chemical bond are described according to the two viewpoints ——energy gradient and electrostatic force. The Mo's bonding properties can be reflected by two aspects of the H-F force vector, size and direction. The same MO has different chemical bonding abilities to different chemical bonds, MO's H-F force of ethylene and cyclopropane are calculated with the ab initio calculation program ABHF, the bonding properties are analysed. The relation between the H-F force and the MO's irreducible representation is presented, a method to decide the molecular geometric configuration variation of excited states by the frontier MO's H-F force is suggested.

OAP can be electropolymerized into an uniform film of active POAP in acid solution. The films formed in different acid solutions have compact or open structures. The main structure of the POAP film is (A), The POAP film can be complexed with Ni~(2+) to form POAP-Ni~(2+) film in which the main structure is (B).

The potential windows of the system water/pure solvent (W/P) and water/solvent mixtures(W/S) have been investigated by cyclic voltammetry with solvents whose dielectric constants lie between 5.67 and 34.82. In the presence of LiCl in the aqueous phase and tetrabutytammoniumtetraphenylborate(TBATPB) in the organic phase, the systems water/allyl iso-thiocyanate (W/AIT) and water/nitrobenzene (W/NB) show a same wide potential window. Thermodynamic parameters of ion transfer across W/AIT interface were determined. In systems of W/P and W/S the influence solvent effect on the standard Gibbs energies of transfer of ion Δ_o~wG_(tr,i)~p was discussed.

Ni(Ⅱ) ion is complexed by poly-8-hydroxyquinoline, poly-0-aminophenol, poly-0-diaminobenzene and polyaniline as ligands. The voltammograms for the polymer-Ni (Ⅱ) film electrode show well defined reduction and oxidation peaks. They have similar electrochemical properties. Poly-8-hydroxyquinoline film, poly-0-aminophenol film and poly-0-diaminobenzene film can be used to exchange Ni (Ⅱ) with H~+ ion and to separate Ni(Ⅱ), Co (Ⅱ) and Fe(Ⅱ) ions.

By electrochemical polymerization of pyrrole in phosphate buffer, glucose oxidase (GOD) was entrapped in polypyrrole matrix (PPy) to construct the enzyme electrode. Effects of electropolymerization conditions, such as pH values and electrode potentials, on the enzyme immobilization were studied. Behavior of GOD/PPy membranes was characterized by IR and a.c. impedance spectra. The immobilization of GOD will be accomplished only if pH>5.5. It is likely that GOD enters into PPy in its entity with negative charge. Spectra of a.c. impedance show that the enzyme electrode has the features similar to porous electrodes. It was edmonstrated that the simultaneous immobilization of GOD and mediator Fe(CN)_6~(3-) is feasible. The electrcchemically immobilized GOD maintains its biocatalytic activeties, and apparently the enzymatic reaction follows Michaelis-Menten kinetics.

A equation between the thermodynamic properties and the retention values of capillary gas chromatography was proposed. The thermodynamic properties of nitromethylaniline isomers on cros3linking SE-30, SE-54 and noncrosslinking SE-54 fused silica capillary columns have been calculated and the results were interpreted qualitatively.

In this paper, the total energies and band structures of polydiacetylenes(acetylenic structure and butatrienic structure) are calculated by use of LCAO-SCF ab initio crystal orbital (CO) method. The energetic stability and the band structures of the different structures of polydiacetylenes are discussed and analyzed. The influence of side groups on the energies and band structures of polydiacetylenes is also discussed.

In this work, expressions for the steady state voltammetric curve of a microdisk electrode are derived by using "uniform concentration" approach. For reversible electrode reactions, the derived expression is exact, while for irreversible and quasireversible reactions, the expressions are approximate.In the case of irreversible reaction, the maximum relative error of the current calculated from the given expression is about 4%. The approximate expression has the form similar to those for conventional planar electrodes. The relation between the upper limit of measurable rate constant and the radius of microdisk electrode is also discussed.

The oscillatary behavior of diacetone alcohol(DA)-KIO_3-H_2O_2-H_2SO_4-Ce~(3+) system has been studied.The system may oscillate in the concentration ranges of H_2SO_4 0.11—0.24, KIO_3 0.019—0.048; Ce~(3+) 5.95×10~(-4)—3.57×10~(-3), DA 0.4—3.22 and H_2O_2 0.40—1.99 mol·dm~(-3) respectively.
Using Hg_2SO_4 electrode as the reference electrode, the potential of I~- and the redox potential show oscillatary wave behavior in XWT balance recorder.
According to our expreimental results, We may said seen that ...

The structure of the product from the [2+2] photocycloaddition of acetylacetone to methyl 1-naphthoate was determined by X-ray crystallography. Crystal data. C_(17)H_(18)O_4, triclinic, P_1~-, a=0.7401(1), b=0.7656(1), c=1.3882(1) nm, α=84.75(1), β=86.49(1), γ=65.08(1)°, V=0.7102 nm, Z=2, D_c=1.339 g·cm~(-3), μ(MoK_a)=1.0 cm~(-1), F(000)=304. The structure was solved by direct methods and refined to final R=0.049 for 2442 MoKa reflections. The particular bridged structure of the product molecule indicates a [2+2+2] intramolecular cycloaddition in succession to the primary [2+2] photocycloaddition. Molecular mechanics calculations confirmed further that the molecular structure of the ultimate product takes a configuration of comparatively favourable steric energy even though the bridged structure itself is rather strained.

The structure of the product from photodimerization in non-polar solvent of acetylacetone, C_(10)H_(16)O_4, Mr=200.2, was determined from three-dimensional X-ray data. It crystallizes in the monoclinic, space group P2_1/c, a=1.6766(2), b=0.7736(2), c=1.1024(l) nm, β=130.44(2)°, V=1.0882 nm, Z=4, D_o=1.23, D_c=1.222 g·cm~(-3), μ(MoK_a) =0.877 cm~(-1), F(000) =432. The structure was solved by direct methods and refined to R=0.040 for 1861 observed MoK_a reflections. The ultimate product is a furanoid derivative which has a minimum steric energy according to the molecular mechanics calculations. Possible reaction pathway of the photocycloaddition was also discussed.

The concept of fractal was applied to interpret the surface of porous solids and the processes proceeded on them. The fractal dimensions were determined from the saturation coverage with different adsorbates.The number of molecules reaching mon olayer coverage scale down with increasing σ as
N～σ~(-D/2)
where σ is the cross section of the probe molecule.
As the porous materials (such as porous silica gel, alumina) were mixed with a few of other active components (Zn(Ac)_2, CuCl_2), it is found that the fractal ...

In this paper we used the flowing-afterglow technique to study the energy transfer processes in the reaction of metastable atoms Ar, Ne, and He with CCl_4 and CBr_4, The emission spectra of excited fragments CCl (A—X), Cl_2~* and Br_2~* were obtained. The reaction mechanism were discussed.

The excited fragments CH(A), CH(B), CH(C) etc. were produced by the bombardment of He(2~3S) with CH_nX_(4-n)(X=Cl, Br, I). Based on the CH(A-X) emission spectra, the rotational populations can be interpretated in terms of Boltzmann distribution. The effective rotational temperature for CH(A,v'=0) produced from various methyl halides are nearly the some. Experiments under various pressure and calculation of collisional dynamics showed that the distributions are approximate to the nascent distributions.

The structure defect of electrodeposited tin was investigated by means of positron annihilation lifetime spectroscopy. It was observed that when annealing temperatures were less than 120 ℃, the vacancies aggregated into a cluster; in the region of 120 —160 ℃, the structure defects changed considerably, some vacancy cluster enlarged and some shrunk due to thermal migration of the atoms; the recrystallization of deposits took place in temperature of 180 ℃, in this case the positrons were premarily annihilated in the expanded crystal boundary.