砷铋钼三元杂多酸-羧甲基纤维素钠的极谱行为研究及微量砷的测定与应用

本文研究了砷铋钼杂多酸的极谱行为。该杂多酸络合物先在低酸度下迅速形成钼蓝,然后在0.4mol/LH_2SO_4中此杂多酸电活性络合物在滴汞电极上于—0.47(vs.SCE)产生灵敏的络合物吸附还原波。当存在CMC时灵敏度进一步提高,用二次微分极谱测试,波形良好,峰锐且呈对称。As 0.01～2.5μg/ml浓度与波高呈线性,检出限为0.blμg/ml,它比二元杂多酸极谱性能优越。方法应用于岩石及辉锑矿中微量砷的测定,结果令人满意。     

生物可降解磷酸酯-碳酸酯共聚物的合成及性能研究

通过光气，二氯磷酸酯和双酚Ａ反应，合成六种磷酸酯 碳酸酯共聚物，用ＩＲ、１Ｈ ＮＭＲ及元素分析表征了共聚物，测量了Ｍｎ和热学性质．初步研究了在ｐＨ７４磷酸盐缓冲溶液中，核糖核酸酶或碱性磷酸酶存在下的体外降解性能及其对抗肿瘤药物５ Ｆｕ的释放性能．     

Dielectric constants of acetonitrile, γ-butyrolactone,propylene carbonate,and 1,2-dimethoxyethane as a function of pressure and temperature

The dielectric constants of 1,2-dimethoxyethane, acetonitrile, -butyrolactone, and propylene carbonate were determined from capacitance measurements extrapolated to infinite frequency; ln are reported as a function of pressure up to 80 MPa at 15, 25, 35, 45°C and as a function of temperature in the range 10 to 50°C at 0.10133 MPa. The variation of ln with temperature or pressure can be expressed by a second order polynomial expression. The isothermal compressibilities of the solvents were determined at 25°C from sound velocities, densities, and heat capacities. A simple correlation can be established between ln /P and for most aprotic solvent.     

Immobilization of Acidithiobacillus ferrooxidans with complex of PVA and sodium alginate

A new Acidithiobacillus ferrooxidans cell immobilization technique utilizing the complex of PVA solution and sodium alginate solution crosslinked by Ca(NO₃)₂ as entrapment medium is reported. The mixture of A. ferrooxidans suspension and the entrapment complex were extruded into a solution of Ca(NO₃)₂ (1-5%) to form beads, then the beads were frozen at −20 °C for 1-2 days and thawed at room temperature. The forming mechanism, characteristic of this immobilized beads and the factors affecting activity of immobilized cells were also discussed. A maximum oxidation rate of 4.6 g Fe²⁺/(L h) was achieved in batch cultures by these immobilized cells. Precipitation formed during culture process was analyzed. The forming mechanism of this precipitation and how this precipitation affects the whole system were also discussed. In addition, the immobilization technique is operated simply, and the gel beads have high stability even under non-sterile conditions. So its application on an industrial scale would be more practicable.     

乳状液膜法制备超细碳酸钙

探讨了不同流动载体的煤油、司本 - 80与碳酸钠水溶液制成的乳状液的稳定性 .考察了外相氢氧化钙水溶液中Ca2 + 浓度、膜相磷酸三丁酯的量及乳水比等因素对Ca2 + 迁移率的影响 .经TEM测定 ,破乳后的沉淀颗粒粒径不超过 10 0nm .     

Studies on sulfinatodehalogenation: The addition of polyfluoroalkyl iodides to olefins promoted by sodium bisulfite and sodium sulfite

The reaction of polyfluoroalkyl iodides with alkenes or 4-pentenoic acid promoted by sodium bisulfite or sodium sulfite in DMF aqueous solution was realized. The reaction of alkenes gave corresponding adducts, while γ-lactones were obtained in the case of 4-pentenoic acid in good yields.     

A green route for microwave synthesis of sodium tungsten bronzes NaxWO3 (0<x<1)

A green route has been developed for microwave synthesis of sodium tungsten bronzes Na_xWO₃ (0<x<1) from Na₂WO₄, WO₃ and tungsten powder. The hybrid microwave synthesis was carried out in argon atmosphere using CuO powder as the heating medium. Tungsten powder is used as the reducing agent instead of the alkali metal iodides previously used for the microwave synthesis of oxide bronzes. The prepared samples were characterized by powder X-ray diffraction, energy-dispersive X-ray analysis and scanning electron microscopy, and their phase constitutions, crystal structures and morphologies are in consistence with that in the literature. This synthesis method is simple, green and atom economic, and promising for preparation of other oxide bronzes and related compounds.     

Excess molar volume of dimethyl carbonate +p-xylene + n-decane at 288.15 and 298.15 k

Densities for dimethyl carbonate + p-xylene + n-decane ternary system, at 288.15 and 298.15 K and at atmospheric pressure, were measured. The corresponding excess molar volumes were calculated from the experimental data and were fitted by means of Cibulka equation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Zur Kenntnis von Na4Br(NH2)3: Ein Amidbromid im System NaNH2/NaBr

Na₄Br(NH₂)₃: An Amide Bromide in the System NaNH₂/NaBr The pseudobinary system NaNH₂/NaBr was investigated by X-ray methods. The crystal structure of Na₄Br(NH₂)₃ was solved by single crystal data: Pnnm, Z = 4, a = 6.579(2) Å, b = 12.755(4) Å, c = 8.776(2) Å Z(F_o) with (F_o)² ≥ 3σ = (F_o)² = 503, Z(parameter) = 39, R/R_w = 0.082/0.106. It is a new type of structure, built up by a three-dimensional network of [Na₄(NH₂)₃⁺] containing the bromide ions.     

Capillary electrochromatography with 1.5 μm ODS-modified non-porous silica spheres

Summary The particle realization of electrochromatography on capillaries packed with 1.5 μm ODS-modified non-porous silica spheres is demonstrated. In order to realize stable separation conditions it is crucial to add sodium dodecylsulphate (SDS) to the mobile phase and to pressurize both buffer vials at 10 bar. The presence of SDS stabilizes the current and makes the electro-osmotic flow in the packing more uniform so that no air bubbles are generated at high field strengths. The capillary columns are extremely efficient and on a 24 cm long column about 120,000 plates can be generated (a reduced plate height of about 1.3). The columns are very stable and no loss in efficiency was found after using a column continuously for two months.