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941.
The possibility of humic acids acting as micellar phase in micellar electrokinetic chromatography was evaluated. We investigated the separation of naphthalene in capillary electrophoresis using various samples of humic acids as micellar phase under different pH conditions, concentrations of humic acid, and temperature. The humic acid samples studied were from different origins including peat, vermicompost and a commercial sample acquired from Aldrich. Methanol was used as a marker for the electroosmotic flow. The results indicate that the formation of micelle depends on the number and nature of the hydrophobic association sites in an aqueous humic acid solution and on the origin and concentration of the humic acid at a defined pH. At lower pH values, the possibility of the humic acid molecule forming pseudomicelles increases due to a combination of neutralized and dissociated charged sites. 相似文献
942.
Bitao Su Ke Wang Jie Bai Hongmei Mu Yongchun Tong Shixiong Min Shixiong She Ziqiang Lei 《Frontiers of Chemistry in China》2007,2(4):364-368
Fe3+-doped TiO2 composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized
by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance
spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic
activity of Fe3+/TiO2 nanoparticles under visible light irradiation. The influence of doping amount of Fe3+ (ω: 0.00%–3.00%) on photocatalytic activities of TiO2 was investigated. Results show that the size of Fe3+/TiO2 particles decreases with the increase of the amount of Fe3+ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe3+ can control the conversion of TiO2 from anatase to rutile. The doping amount of Fe3+ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The
appropriate doping of Fe3+ can markedly increase the catalytic activity of TiO2 under visible light irradiation.
__________
Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)] 相似文献
943.
Radoslav D. Mii Radmila P. Marinkovi-Neduin Zoltán Schay István Nagy Jelena S. Kiurski Ern E. Kiss 《Reaction Kinetics and Catalysis Letters》2007,91(1):85-92
Investigations of a commercial NiMo/Al2O3 hydrodesulfurization (HDS) catalyst are directed towards optimization of the activation procedure of HDS catalyst concerning
active phase formation and thermal stability. Structural and textural data obtained with XRD, IR-FTIR, XPS and LTNA reveal
that the optimal temperature for the formation of active species on the catalyst surface and an appropriate pore structure
is 300°C. 相似文献
944.
Fluorimetry has been used to characterize ionomers synthesized by copolymerization ofmethyl mehacrylate, methacrylic acid and europium methacrylate (EMA). Under excita-tion of UV light at 375 nm no seif-quenching was found in fluorescence of EMA containingionomers at 615nm within the concentration range of 1.6×10~(-2) to 11.49×10~(-2) mol%.This means that the distance between two Eu~(3+) ions is larger than 5nm. In the sameconcentration range seif-quenching took place in europium octanoate (EOA) containingpoly(methyl methacrylate) in which EOA was doped as an additive. 相似文献
945.
铕掺杂BaPbO3的EXAFS研究 总被引:3,自引:0,他引:3
采用扩展X射线吸收精细结构方法,研究了铕掺杂BaPbO3多晶粉末中Eu,Pb两种原子的近邻结构。Eu的掺杂,导致八面体中金属Pg,Eu的配位数降低。 相似文献
946.
Conditions for the formation of rare earth element (Y, La–Lu) 3-methylglutarates were studied and their quantitative composition
and solubilities in water at 293 K were determined (10–2 mol dm–3). The IR spectra of the prepared complexes with general formula Ln2(C6H8O4)3
nH2O (n=3–8) were recorded and their thermal decomposition in the air were investigated. During heating the hydrated 3-methylglutarates
are dehydrated in one step and next anhydrous complexes decompose to oxides Ln2O3 with intermediate formation Ln2O2CO3 (Y, La, Nd–Gd) or directly to the oxides, Ln2O3, CeO2, Pr6O11 and Tb4O7 (Ce, Pr, Tb–Lu).
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
947.
The crystal structure of new compound Ba3BPO7 was determined by ab initio method from high-resolution conventional X-ray powder diffraction data. The Rietveld refinement converged to Rp=5.92%, Rwp=8.87%, Rexp=5.00% with the following details: Hexagonal, space group P63mc, a=5.4898 (1) Å, c=14.7551(1) Å, Z=2. The basic unit of the structure is the [BaO10]-[BO3]-[PO4] polar polyhedra-chain composed of Ba1-B-P-O cluster. These chains, running along c-axis, stack in a HCP mode to build the whole structure with triangular prism channels. The channels are parallel to c-axis too, in which Ba2 and Ba3 are located. 相似文献
948.
949.
K. Grob 《Journal of separation science》1978,1(5):263-267
During one year continuous use of on-column injection, the typical advantages described in our first report have fully been confirmed. In addition the analysis of large sample volumes has proved promising. Only minor modifications have been applied to the on-column injector device. Broad evidence has been gathered showing that full separation efficiency of the capillary columns after on-column injection is attained only when cold trapping or the solvent effect, as band shortening mechanisms, are working- While, under the conditions of on-column injection, cold trapping is less efficient than with other injection techniques, the opposite holds true for the solvent effect. Compared with splitless injection, the danger of excessive solvent condensation on the column is increased. A working rule is presented for establishing the optimal chromatographic conditions for handling large sample volumes while ensuring full separation efficiency yet avoiding harm to the column. 相似文献
950.
The interaction of aryldiazonium ions with some Schiff-base complexes of cobalt and ruthenium have been studied. With cobalt, one-electron oxidation of [Co(II)Salen] occurred; with [Co(I)Salen] the corresponding Co(III)-aryl complexes were isolated. In the case of ruthenium oxidation also occurs, [Ru(Salen)(CO)py] gave the corresponding monocation. The results, especially for ruthenium, are in contrast to the stabilisation of both nitrosyl and aryldiazonium adducts in analogous porphyrin complexes. 相似文献