A Novel Composite Electrode of Photocatalyst—TiO2／C Loading on the Surface of the Air （Oxygen） Electrode

The methods for preparing the H2O2 generating air (oxygen) electrode and the composite electrode of photocatalyst-TiO2/C loading on the surface of the air (oxygen) electrode were introduced.In the case of the composite electrode,the current efficiency of electro-generated H2O2 is higher than 80%(J≤15mA/cm^2).The degradation of aniline was used as an example to measure the influence of the composite electrode and compared with the system in which the air (oxygen) electrode and the photocatalyst-TiO2 were sqparated.The results confirmed that the composite electrode played an active role on accelerating the degradation rate of aniline.According to the measurement of the polarization curves of composite electrode and TiO2 photo anode,and of the adsorbing amount of aniline on the surface of the composite electrode,the principle of descending the recombination reta of photo-generated electron and hole and of enhancing the oxidation rate of organic molecule was described.The mechanism about the degradation of aniline was also discussed.     

Studies on Kinetic Properties of Active Oxygen on the Surfaces of V_2O_5/SiO_2, V_2O_5-MoO_3/SiO_2 and V_2O5-P_2O5/SiO_2 Catalysts

Applying the TPD-MS with a high sensitivity of determination, the TPD spectrum of surface oxygen of V2O5/SiO2, V2O5-MoO3/SiO2 and V2O6-P2O5/SiO2 catalysts was obtained. The surface oxygen of these catalysts can be divided into three groups according to the desorption temperature. O2- desorbs mainly from 373K. to 423K, O- from 673K to 873K and O2- at above 873K. The activation energy and frequency factor of all the three kinds of oxygen species were calculated. Based on these results, the mechanism of oxygen desorption and the influence of P2O5 and MoO3 on the properties of oxygen supply of V2O5/SiO2 catalst were investigated. MoO3 and a small amount of P2Os increase the number of supplying oxygen and increase the activity of O- species. A large amount of P2O5 increases the number of supplying oxygen and restrains the activity of O- species.     

CATALYTIC ACTIVITY OF Pd-Sn COMPLEX CARBONYLATION OF ACETYLENE

The influence of different concentration of HO, SnCl2, Cl- and n-BuOH on the carbonylation of acetylene has been studied. The results show that the yield of n- butyl propionate increases with the increase of HC1 concentration and the catalytic activity is depressed when Cl" concentration increases. However, the stability of catalytic complex is promoted by Cl-. The key to the carbonylation of acetylene lies in the addition of SnCl2, which promotes the formation of the complex of C2H2, CO with catalyst and plays an important role in the hydrogen removal from n-BuOH. The hydrogen removed from n BuOH is the hydrogen source of this reaction. Meanwhile, the principle of the effect of HCl, Cl- and SnCl2 on reaction has been discussed. The reaction model has also been proposed.     

Functional Mechanism of Resveratrol in Inhabiting Growth of Cells Is174t and Its Mechanism in Subcutaneously Transplanted Tumor of Nude Mice

To explore the functional mechanism of Resveratrol against colon cancer cells ls174t and the growth of colon cancer tissue of tumor-bearing mice, MTT method was used to observe the functions of resveratrol for inhibition against cells ls174t in vitro. Transmission electron microscope was used to observe the cell apoptosis. FCM assay was performed to measure the change of the cell apoptosis rate and of cell cycle. RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA. Western blot method was used to detect the expressions of bcl-2 and bax protein. Ceils ls174t were transplanted subcutaneously to nude mice to observe the effect of resveratrol on the growth of subcutaneously transplanted tumor, RT-PCR method was used to detect the expressions of bcl-2 and bax mRNA in the tumor tissue. Western blot method was used to detect the expressions of bcl-2 and bax protein in the tumor tissue. Resveratrol has an effect of inhibiting proliferation of cells ls174t in vitro（P〈0.01）. It is able to induce the apoptosis of cells ls174t, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol could inhibit the growth of subcutaneously transplanted tumor of nude mice（P〈0.05）, causing the decrease in the expression of bcl-2 and the increase in the expression of bax. Resveratrol can inhibit the growth of cells 174t and the growth of subcutaneously transplanted tumor. The mechanism is possibly related to the induction of the cell apoptosis and the regulation of bcl-2/bax expression.     

微量热法研究亚砷酸钠对鲫鱼肝脏线粒体的影响

Metabolic thermogenic curves of mitochondria isolated from liver tissue of Carassius auratus and the effect of different concentration of NaAsO2 on it were investigated by TAM air isothermal microcalorimeter, ampoule method, at 28.00 ℃. From the thermogenic curves, activity recovery rate constants k, the maximum heat production rate （Pmax） and the total heat produced （Q） were obtained. The values of k and Pmax decline gradually with the increase of the concentration of NaAsO2, and both of the values of Pmax and k are highly correlated to the concentration of NaAsO2. When concentration of NaAsO2 reached 16.0 μg/mL, the maximum heat production rate dropped to 70.8% of the control group, and the corresponding percentage of k was 71.4% of the control group. This experimental result indicates that the addition of NaAsO2 has restrained the metabolic activities of mitochondria in vitro.     

PACKING OF IONS IN SILICATE GLASSES

Any silicate glass can be regarded as the relaxation of SiO_2 glass and the volumeis composed of two parts. One is the topological volume of O~(2-), which is equal to thevolume per oxygen of SiO_2 glass, the other is the topological volumes of cations. Thetopological volume of a monovalent cation equals the volume shared by each sphere indense haphazard packing of equal spheres of the cation's size. The charges of bivalentcations cause a decrease of volume, the decrement being the packing volume of Ca~(2+). Anequation is reached for the calculation of the volume per oxygen of silicate glasses. Alot of calculations show that the equation is accurate, so accurate that the densities canbe calculated. The study reveals some characters of the glass structure and clearly ex-presses the contributions of various cations to the volumes of glasses.     

Fe(OH)2悬浮液在EDTA作用下氧气氧化生成δ-FeOOH的机理研究

At room temperature and in the presence of trace EDTA, the formation of δ-FeOOH was studied by the rapid oxidation of Fe(OH)2 suspension with O2. The structural and morphological changes were characterized by various techniques such as XRD, FTIR and TEM. γ-FeOOH and δ-FeOOH formed simutaneously in the early period of oxidation. But as the rate of mass transfer was in equilibrium, trace γ-FeOOH vanished gradually. Accordingly, pure phase δ-FeOOH was obtained. At the same time, critical amount ratio K of EDTA to Fe^2 was verified. The experiments show that the reactivity, rate of the oxidizing agent and pH of the initial medium were important factors for the formation of pure phase δ-FeOOH. Under the auxiliary effect of EDTA, the reactivity of O2 was nearly improved to that of H2O2. And the process of the oxidation that Fe(OH)2 suspension was oxidized by O2 under that condition was discussed.     

Selective hydrogenation of benzene to cyclohexene over Ce-promoted Ru catalysts

Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.     

The influence of electrochemical treatment on electrode reactions for vanadium redox-flow batteries

Through targeted and reproducible electrochemical treatment of glassy carbon electrodes,investigations have been carried out on the electrochemical behaviour of the oxidation of V~(2+),VO~(2+)and the reductions of VO_2~+,VO~(2+)and V~(3+)in order to pretreat electrodes specifically for use in vanadium redox flow batteries and,if possible,to treat them in situ.For this purpose,a glassy carbon electrode was treated potentiostatically for a period of 30 s at different potentials in the range of 500 mV–2000 mV vs.Hg/Hg_2SO_4in2 M H_2SO_4and then linear sweep voltammograms were performed in the different vanadium-containing solutions.With this method,it could be shown that all reactions are extremely surface sensitive and the reaction speeds changed by several decades.The reaction rates increased significantly in all reactions compared to polished electrodes and had an optimum treatment potential of approx.1600 mV vs.Hg/Hg_2SO_4,although the oxidation reaction of V~(2+)and the reduction reactions of V~(3+)and VO~(2+)had opposite tendencies to oxidation of VO~(2+)and the reduction of VO_2~+in the area of low treatment potentials.In the former,the kinetics increased and in the latter,they decreased.In addition,causes were investigated using confocal microscopy and XPS.No correlation was found to the roughness or size of the stretched surfaces,although these changed significantly as a result of the treatment.XPS measurements gave indications of a dependence on hydroxyl groups for the oxidation of VO~(2+)and the reduction of VO_2~+,while for the reactions of oxygen-free cations and the reduction of VO~(2+)weak indications of a dependence on carboxyl groups were obtained.     

THE STUDY ON PARTIAL OXIDATION OF METHANE TO METHANOL AND FORMALDEHYDE

Several kinds of metal oxides such as Cr_2O_3, MoO_3, V_2O_5 andBi_2O_3 were used as the catalysts for partial oxidation of methane to methanoland formaldehyde. The effects of the preparation and the supports on the char-acteristics of catalysts were studied. It was found the methods of impregnationaffected the characteristics of catalysts greatly. Two kinds of supports (SiO_2,Al_2O_3) have also been compared. In direct conversion of methane to CH_3OH,CH_2O by controlled oxidation, SiO_2 is better than Al_2O_3 as the support of cata-lysts.     

Preparation and Sensitivity of SnO2 Grafted MCM-41 Sensor

Tin dioxide is one of the most widely used semiconductor gas sensor to detect reducing gases1-3. The sensing mechanism of SnO2 is usually based on the change of the resistance of the sensor in different gas environment. In air, the surface-adsorbed oxygen species on the surface of SnO2 act as surface acceptors of electrons, hence diminishing the conductivity of SnO2. However, when reducing gases such as H2, CO, or CH4 are introduced in the air stream, the resistance of the SnO2 sensor is …     

CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE FILLED WITH SiO2 NANOPARTICLES

Oleic acid （OA）-modified SiO2 （OA-m-SiO2） nanoparticles were prepared using surface modification method. Infrared spectroscopy （IR） was used to investigate the structure of the OA-m-SiO2 nanoparticles, and the result showed that OA attached onto the surface of SiO2 nanoparticles through esterification. Effect of OA concentration on the dispersion stability of OA-m-SiO2 in heptane was also studied, and the result indicated that OA-m-SiO2 nanoparticles were dispersed in heptane more stably than the unmodified ones. OA-m-SiO2 nanoparticles can also be dispersed in polypropylene （PP） matrix in nano-scale. The effect of OA-m-SiO2 on crystallization of PP was studied by means of DSC. It was found that the introduction of OA-m-SiO2 resulted in significant increase in the crystallization temperature, crystallization degree and crystallization rate of PP, and OA-m-SiO2 could effectively induce the formation of β-crystal PP. Effect of OA-m-SiO2 content on mechanical properties of PP/OA-m-SiO2 nanocomposites was also studied. The results show that OA-m-SiO2 can significantly improve the mechanical properties of PP.     

Characterization and catalytic performance of CeO2-Co/SiO2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species （-CH2-）. Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity （GHSV）, and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.     

二氧化钛膜参数对离子液体基染料敏化纳米薄膜太阳电池性能的影响

Photo correlation spectroscopy was used to measure the particle size distribution of TiO2 films. Other parameters, such as porosity, BET surface area, average pore size, crystallite size D101, distribution of pore size etc. were also measured. The effects of these parameters on the ionic liquid based dye-sensitized solar cells （DSC） were studied. It was concluded that the particle size distribution of nanocrystalline TiO2 played an important role on the performance of DSC. The narrow particle size distribution of nanocrystalline TiO2 increased the efficiency of DSC, while the wide distribution decreased the efficiency of DSC. From the result above, it was also concluded that the photo correlation spectroscopy was a good method to identify the performance of TiO2 films. Based on electrochemical impedance spectroscopy, we found that the particle size distribution could affect the electronic contact between the TiO2 layers as well. The narrow particle size distribution made the electronic contact between TiO2 layers better than the wide particle size distribution of the TiO2 films, and then better the electronic contact, higher the efficiency of the DSC.     

EFFECTS OF La_2O_3 LOADING MANNER ON THE CHEMISORPTION AND HYDROGENATION OF CO ON La_2O_3-PROMOTED Pd/siO_2

The effects of La_2O_3 as a promoter of Pd/SiO_2 catalyst and its loading manner on thechemisorption and hydrogenation of CO have been investigated using in situ FTIR,TPSR,CO adsorp-tion,activity evaluation of methanation and TEM.The results show that the addition of La_2O_3 to thePd/SiO_2 can promote the dissociation and hydrogenation of CO,but causes a noticeable suppression inchemisorption of CO.This is probably due to partially reduced La_2O_3 moieties which decorate the sur-face of Pd particles.In addition,the effects of La_2O_3 promotion on the adsorptive and reactive propertiesof Pd/SiO_2 depend strongly on the loading manner of La_2O_3.It means that the method of preparationhas a significant effect on the degree of interaction between La_2O_3 and the surface of Pd particles.     

The protection effect of β-CD on DNA damage induced by ultrafine TiO_2

Under the photocatalysis of 365 nm ultraviolet radiation,ultrafine TiO2 caused the oxidative damage of Teasy plasmid DNA. The damage was determined by gel-electrophoresis. Then,a different dose of β-CD was added to the reaction,and the damage was restrained. The rate of damage restraining reached 97% when the mass of β-CD was 4 times as that of TiO2. Through UV scan and IR spectroscopy,it was found that the Ti-O of ultrafine TiO2 was bound with -OH of β-CD cavum and the -OH on the surface of ultrafine TiO2 disappeared,so the formation of ?OH was controlled. The ultrafine TiO2 has been widely used,but it was determined to be carcinogenic by some research. The protection effect of β-CD to DNA in the molecular level takes a new look on the surface modification of nano particles to decrease the toxic effect.     

The protection effect of β-CD on DNA damage induced by ultrafine TiO2

Under the photocatalysis of 365 nm ultraviolet radiation, ultrafine TiO2 caused the oxidative damage of Teasy plasmid DNA. The damage was determined by gel-electrophoresis. Then, a different dose of β-CD was added to the reaction, and the damage was restrained. The rate of damage restraining reached 97% when the mass of β-CD was 4 times as that of TiO2. Through UV scan and IR spectroscopy, it was found that the Ti-O of ultrafine TiO2 was bound with -OH of β-CD cavum and the -OH on the surface of ultrafine TiO2 disappeared, so the formation of · OH was controlled. The ultrafine TiO2 has been widely used, but it was determined to be carcinogenic by some research. The protection effect of β-CD to DNA in the molecular level takes a new look on the surface modification of nano particles to decrease the toxic effect.     

富氧条件下乙炔选择催化还原NOx

Acetylene as a reducing agent of metal exchanged HY catalysts, for selective catalytic reduction of NO in the reaction system of 0.16% NO, 0 （C2H2-SCR） was investigated over a series 08% C2H2, and 9.95% O2 （volume percent） in He. 75% of NO conversion to N2 with hydrocarbon efficiency about 1.5 was achieved over a Ce-HY catalyst around 300 ℃. The NO removal level was comparable with that of selective catalytic reduction of NOx by C3H6 reported in literatures, although only one third of the reducing agent in carbon moles was used in the C2H2-SCR of NO. The protons in zeolite were crucial to the C2H2-SCR of NO, and the performance of HY in the reaction was significantly promoted by cerium incorporation into the zeolite. NO2 was proposed to be the intermediate of NO reduction to N2, and the oxidation of NO to NO2 was rate-determining step of the C2H2-SCR of NO over Ce-HY. The suggestion was well supported by the results of the NO oxidation with O2, and the C2H2 consumption under the conditions in the presence or absence of NO.     

Investigation of Mechanisms About Effects of Promoters P_2O_5,K_2O and A1_2O_3 on Oxidation of o-Xylene to Phthalic Anhydride

We succeeded in designing an effective catalyst, V2O5-P2O5-K2O/Al2O3. SiO2, by which a high yield of PA,105wt% can be gained in middle-sized industrial fluidized bed apparatus without addition of any promoting gas.The mechanisms of effects of P2O5, K2O and Al2O3 on the surface properties of V2O5 were investigated by means of TPD and XRD. And the selectivity of oxidation are explained.Addition of a great deal of P2O5 restrains the activity of donating surface oxygen from V2O5, but increases the number of sites which donate surface oxygen. Addition of K2O promotes donation of surface oxygen from V2O6, and decreases the number of sites of donating oxygen, on the other hand, addition of K|O makes the surface structure of V2O5 catalysts more stable. Coating a small amount of Al2O2 onto support, SiO2, restrains the activity of donating oxygen and increases the number of sites of donating surface oxygen from V2O5.     

Soluble Expression, Purification and Characterization of Single-chain Fv Catalytic Antibody（sFv-2F3）

To find optimal conditions for expressing the soluble form of sFv-2F3 and to study the purification andproperty of its derivative Se-sFv-2F3, the preferred expression conditions were investigated by means of or-thogonal design. These culture conditions included incubation temperature, inducer concentration, inductiontime and cell concentration. The evaluation of expression was accomplished by the analysis of whole celllysates and the yield of soluble sFv-2F3 was calculated according to the analysis of Profinder(FTI-500,Phar-macia). The purification procedure was carried out via a two-step purification procedure consisting of ion-ex-change chromatography, followed by immobilized metal affinity chromatography(IMAC). The antioxidantefficacy of Se-sFv-2F3 was demonstrated by the determination of the content of the main product of lipid per-oxidation, MDA, the viability of cells and the activity of LDH. We obtained the preferred culture conditionsto grow the engineered bacteria and the procedure for preparing soluble sFv-2F3 and confirmed the antioxi-dant efficacy of Se-sFv-2F3.