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1.
2.
Preparation and Characterization of CuCrZrSe4 and CuCrSnSe4 Single Crystals Single crystals of the compounds CuCrZrSe4 and CuCrSnSe4 were grown by chemical transport using mixtures of AlCl3/I2 as transporting agents. Characterization of the crystals was done by X-ray methods. The compounds are normal spinels, the space group is Fd3m. The results of least squares refinement using single crystal X-ray data are reported. 相似文献
3.
The spinels of the system LixMn1?xV2O4 (0 ? x ? 1) have been prepared at 700–750°C from LiV2O4 and MnV2O4. The lattice constants decrease linearly with increasing x. In the region x>0.75, the d-electrons of V should be delocalized as the VV distances are lower than the critical VV separation of 2.94 Å. Experimentally, the samples with x>0.6 show no IR absorption bands and the Seebeck coefficient is near zero. The Seebeck coefficient can be described with a model of intermediate polarons and can be expressed by the equation . 相似文献
4.
The solid-state reaction of the second kind in a sandwich type diffusion couple of and β-Ga2O3 has been investigated between 1249 and 1550°C in air. The quantity z, which corresponds to the saturation concentration of β-Ga2O3 in CoO, was determined as a function of temperature by X-ray methods and the optical microscope; the homogeneity range of the spinel phase was investigated also. The growth of the thickness of the reaction layer follows a parabolic rate law; the activation energy is 71.6 kcal/mole. A comparison of reaction rate constants of the first and second kind in connection with experimental results, achieved with a modified marker technique, leads to confirmation of the Wagner mechanism for the formation of CoGa2O4 spinel as supposed before by Laqua. Reaction rate constants of the second kind, calculated from interdiffusion profiles in CoO-β-Ga2O3 diffusion couples, are in good agreement with experimental values. Presented data are used for estimating interdiffusion coefficients for the CoO-β-Ga2O3 system according to theoretical aspects developed by Pelton, Schmalzried, and Greskovich. 相似文献
5.
O. Reuter R. Langley Dr. Wan Manshol Bin W. Zn 《Radiation Physics and Chemistry》1998,52(1-6):429-432
This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include
- • * the irradiation vulcanisation of natural latex rubber
- • * disinfection of municipal sewage sludge for agricultural use
- • * sterilisation of liquids in the pharmaceutical and cosmetics industries
- • * industrial processing of bulk liquids
The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments.
The design allows irradiation processing to be carried out under an inert or other gaseous environment.
State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers. 相似文献
6.
Gel swelling experiments have been used to study the binding of ionic surfactants to a series of nonionic alkylacrylamide hydrogels of increasing hydrophobicity. The binding of hexadecyl trimethylammonium (C16TA+) to uncharged gels is sensitive to both the hydrophobicity of the gel and the counterion to the surfactant. There is a minimum hydrophobicity threshold below which binding of the surfactant does not occur, and this is influenced by the counterion to the surfactant. The surfactant concentration at the onset of binding, the critical association concentration (cac), decreases with increasing gel hydrophobicity. The maximum swelling of the gel (at intermediate network hydrophobicity) increases in the order of the Hofmeister series of anions, bromide (Br-) < chloride (Cl-) < acetate (Ac-). At higher gel hydrophobicity, differences in swelling are no longer observed on changing the counterion. A minimum hydrophobicity threshold was also found for the binding of the anionic surfactants sodium dodecyl sulfate (SDS) and sodium dodecyl-di(ethylene oxide)-sulfate (SD-(EO)2-S). Differences in the swelling behavior with network hydrophobicity are explained in terms of the degree of saturation of the gel with surfactant at the cmc. 相似文献
7.
Empirical solvent parameters of silica surfaces are determined by means of solvatochromic dyes, e.g., Cu(tmen) (acac)+ ClO
4
–
/B(C6H5)
4
–
, Fe(phen)2(CN)2, and Michlers Ketone dissolved in 1,2-dichloroethane or cyclohexane. The values obtained by UV/VIS-measurements are compared with both the polarity scales of Kamlet and Taft and with Gutmann's donor and acceptor numbers. Kamlet and Taft's -parameter (the hydrogen-bond donation capacity of a solvent) is determined independently by means of salicylideneaniline. The * of silica is determined using 5-N,N-dimethylamino-5-nitro-2,2-bithiophene and the complex of tetracyanoethylene with Michlers Ketone, respectively. Further on the reliabilities of the obtained Kamlet-Taft parameters , , and * are checked by comparism with experimental and calculated values of theE
T(30)-parameter of silica by means of multi-parameter regression analysis. The surface properties of silica are influenced mainly by HBD-properties (75%) and dipolarity/polarizability * (20%), but hardly by the HBA-properties (<5%). UV/VIS-measurements were carried out in a special equipment with glass fiber optics, A drawing of the apparatus is given. 相似文献
8.
9.
A novel procedure for immobilization of liposomes inside fused-silica capillaries is demonstrated. First, the inner wall of the capillaries was coated with a positively charged polymer, composed of derivatized agarose. Subsequently, negatively charged liposomes were immobilized by electrostatic interaction on the polymer coating. The developed liposome coated capillaries were used as a nanoseparation tool for studying interactions between small drug compounds and liposomes. Part of this work was presented at the 15th International Symposium on Microscale Separations and Analysis, HPCE 2002, Stockholm, Sweden, April 2002. 相似文献
10.
Abstract Alkyl and aryl thioglycosides were converted in high yield into the corresponding α-glycosyl fluorides by treatment with dimethyl(methylthio)-sulfonium tetrafluoroborate. Glycosidic linkages and most protective groups are not affected by the reaction conditions. Glycosyl fluorides are proposed to be intermediates in glycosylations promoted by dimethyl(methylthio)-sulfonium tetrafluoroborate. 相似文献