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991.
Ren Y  Zhang Z  Ren Y  Li W  Wang M  Xu G 《Talanta》1997,44(10):1823-1831
The classification of normal and cancer groups with four multivariate methods according to metal contents in serum and hair samples has been discussed in the present paper. Results show that the four multivariate methods, stepwise discrimination analysis, principal components analysis, hierarchical cluster analysis, and stepwise cluster analysis can distinguish the two groups correctly. The independent samples of both normal and cancer groups were tested and can be distinguished correctly by the four methods. Therefore, these methods can be used as an aid for diagnosis of lung cancer according to the metal contents in serum and hair samples.  相似文献   
992.
A methodology based on the coupling of experimental design and a modified simplex method is proposed for the optimization of a new flow injection-kinetic system for the spectrophotometric determination of Os (IV) with m-acetylchlorophosphonazo, which has for the first time been used as chromogenic reagent in the quantitative analysis of this element. An orthogonal array design is utilized to design the experimental protocol, in which six variables are varied simultaneously, and obtain the initial simplex using 25 experiments. A modified simplex method is applied to continuously optimize the data of the orthogonal array design; the search for optimum conditions of 6 variables using the modified simplex method required only 25 experiments. The efficiency and simplicity of the coupling of the experimental design and the modified simplex method are attractive for the development of new analytical methods. The method has been applied to the determination of Os (IV) in a refined ore as well as in a secondary alloy and provided satisfactory results.  相似文献   
993.
A composite film of ethylenediamine tetraacetic acid (EDTA)‐ZrO2 organic‐inorganic hybrid was prepared based on the chelation between Zr(IV) and EDTA. The direct electrochemical behavior of cytochrome c (cyt. c) at the hybrid film modified glassy carbon electrodes was investigated. The immobilized EDTA can promote the redox of heme in horse heart cyt. c which gives rise to a pair of reversible redox peaks with a formal potential of 40 mV (vs. SCE). The peak current increased linearly with the increase of cyt. c concentration in the range of 1.6 × 10?6—8.0 × 10?5 mol·L?1 with the correlation coefficient of 0.996. Further investigation shows that metal ions can impede the electron transfer of cyt. c. The impediment capability of metal ions depends on their coordination capability with EDTA and their valence number.  相似文献   
994.
Chen SZ  Xu F  Zhang H  Zhang ZQ 《Talanta》1993,40(10):1551-1555
The electroanalytical chemical properties of buspirone are reported in this paper. A sensitive single sweep voltammetric procedure for trace buspirone determination was developed. The detection limit is 5.0 x 10(-9)M. The method has been applied to the determination of buspirone in blood serum by simple dilution in a buffer.  相似文献   
995.
The nanotitanium dioxide (TiO2) photocatalytic and porous ceramic filtering technique is one of the advanced methods to effectively treat organic wastewater. The TiO2 sol doped with Fe^3+ ions was prepared by sol-gel processing. The influences of the process conditions of coating nanophotocatalytic material- Fe^3+-TiO2 film on the surface of porous ceramic filter by dipping-lift method on the performance of porous ceramic filter were studied. The porous ceramic filters have two functions at the same time, filtration and photocatalytic degradation. The results of this study showed that the pH and viscosity of the sol, amount of Fe^3+ ions doped as well as the coating times greatly affect the quality of coating film, the performance parameters and the photocatalytic activity of the porous ceramic filter. When the pH of the sol is 3-4, the viscosity is about 6 mPa.S, the amount of doped Fe^3+ ions is about 2.0 g/L, the porous ceramic filter has been shown to have the best filtering performance and photocatalytic activity. In this condition, the porosity of porous ceramic is about 42.5%, the pore diameter is 8-10μm. The degradation of methyl-orange is 74.76% under lighting for 120 rain.  相似文献   
996.
[Chemical reaction: See text] A series of BINOL-derived ligands have been prepared and incorporated into ruthenium(II) complexes containing a diamine ligand. The complexes have proven to be excellent catalysts for the asymmetric hydrogenation of ketones, giving reduction products with enantiomeric excesses of up to 99%.  相似文献   
997.
Carbon-supported catalysts were phosphonated using 2-aminoethylphosphonic acid, and the resulting catalysts with largely enhanced proton conductivity performed substantially better than the untreated counterparts in proton-exchange membrane fuel cells.  相似文献   
998.
This paper reports the design of an on-line semi-preparative LC-SPE-NMR system and its use in the structural analysis of mixture components at the 0.02-1% level. The combination provides at least a five fold mass sensitivity increase over that obtained from typical analytical LC-SPE systems and a >30-fold total NMR sensitivity enhancement over analysis by LC-NMR. This is accomplished by using a novel on-line device to store, dilute (1-100-fold) and deliver (at an optimized flow-rate) the isolated component of interest to an SPE trap unit. The SPE unit consists of two cartridges connected in parallel to increase the overall SPE capacity and also to decrease the flow-rate through each trap for enhanced trapping efficiency. As the coupling of semi-preparative LC with NMR (through SPE) is well matched in terms of optimal mass loading for both techniques, only one LC-SPE cycle is required to enrich a 50 microg ml(-1) component (1% in a 5 mg ml(-1) mixture) for the acquisition of heteronuclear (1)H-(13)C NMR data using a conventional NMR flow probe. Furthermore, analytes at the 0.02% level (approximately 1 microg ml(-1)) can be studied using 2D (1)H NMR techniques if peak cuts from replicate sample injections (> or =3) are accumulated into the storage/dilution unit and the resulting solution processed by just one SPE trap and elute cycle.  相似文献   
999.
2-Phenylpyridine activated by chromium tricarbonyl reacts with bis(TMS) ketene acetals to give pyridine-substituted bicyclic γ-lactones. On the other hand, its reaction with the same acetals leads, upon activation with methylchloroformate, to dihydropyridines which can be oxidized to highly substituted, lactone-containing piperidines.  相似文献   
1000.
采用傅立叶变换红外光谱分析了2A12-T6铝合金表面自组装双-(!-三乙氧基硅丙基)四硫化物硅烷偶联剂(SCA)薄膜结构特征,并采用电化学极化曲线评价了薄膜的耐蚀性能.结果表明,铝材表面自然晾干,SCA薄膜分子之间主要通过氢键连接,腐蚀电流密度减小1个数量级以上.120℃的加热处理促进铝板表面通过SiOSi链接而形成SCA网状薄膜结构,并通过在界面上形成SiOAl界面相结构而与铝板表面牢固连接,腐蚀电流密度降低2个数量级以上.SCA乙醇溶液浸泡处理10min比浸泡2s~1min的铝板表面SCA薄膜内氢键缔合羟基要多.  相似文献   
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