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951.
Preparation and Characterization of TiO2-pillared Layered HNb3O8 总被引:1,自引:0,他引:1
IntroductionThelayeredcompoundssuchassmectiteclays,me-tallicphosphatesandtransitionmetaloxidespillaredwithinorganicoxideshavebeenattractingmoreandmoreattentionfrombothacademicandindustrialfieldsduetotheirpotentialapplicationsinadsorption,separa-tion,conductionandparticularlycatalysis.1-7NiobatessuchasKNb3O8andK4Nb6O17,andthecorrespondingprotonicoxides,HNb3O8andH4Nb6O17,aremembersofthefamilyoflayeredtransitionmetaloxidesbasedonoctahedralframeworkstructure,inwhichK+orH+liesbetweenlayersbuil… 相似文献
952.
流动注射pH梯度技术—卡尔曼滤波分光光度法同时测定锶和钡 总被引:1,自引:0,他引:1
本文报道以偶氮氯膦Ⅲ为显色剂,利用流动注射pH梯度技术测定多个不同pH下的吸光度,借助卡尔曼滤波算法进行数据处理,对不同比例的钡锶(Ba:Sr=1:8~8:1)标准混合样品进行了测定,取得了满意的结果。 相似文献
953.
Introduction The development of chiral substances, especially inthe pharmaceutical field, places increasing demands onanalytical methods for the separation of these kinds ofisomers and the chiral purity control of drugs in phar-macokinetic studies. As the enantiomers of epinephrineand salbutamol have different pharmacological andtoxicological characteristics, separation and quantitationof the single enantiomers are required. Analytical methods used so far for the enantiomerseparation inclu… 相似文献
954.
Analysis of Glutamic Acid in Cerebrospinal Fluid by Capillary Electrophoresis with High Frequency Conductivity Detection 总被引:1,自引:0,他引:1
Hai Yun ZHAI Jun Mei WANG Xiao Li YAO Xue Cai TAN Pei Xiang CAI Zuan Guang CHEN* College of Chemistry Chemical Engineering Sun Yat-sen University Guangzhou Department of Chemistry Medical College Sun Yat-sen University Guangzhou The First Affiliated Hospital Sun Yat-sen University Guangzhou 《中国化学快报》2005,16(2):225-228
Glutamic acid(Glu)is the most important amino acid in the nerve center system1.It isessential to detect Glu in cerebrospinal fluids(CSF),because the level of Glu in CSF hasimplicated several diseases such as metabolic diseases or central nervous systemdisorders2.The measurement of Glu in CSF had been performed by high performanceliquid chromatography(HPLC)and capillary electrophoresis(CE)with inducedfluorescence detection3-7.Since Glu shows no fluorescence,different reagents had beenus… 相似文献
955.
Novel pentaerythritol-based carbosilane dendrimers centered at carbon have been synthesised. Starting from tetraallyl ether based upon pentaerythritol as the core molecule, a succession of alternate Pt-catalyzed hydrosilylation of allyl groups with HSiC13 and allylations of SiC1 groups thus introduced with CH2=CHCH2MgBr in THF provided a divergent synthesis of three generations of carbosilane dendrimers in which the Si atoms are linked by CH2CH2CH2 groups. The reaction conditions for hydrosilylation must be well controlled. After purification by chromatography on silica gel pure products for each generation were obtained. The IR, ^1H and ^13C NMR spectra and elemental analysis data are consistent with the proposed structures. The molecular weights of the resulting carbosilne dendrimers have been determined by vapor pressure osmometry. 相似文献
956.
Jian Bin LUO Qiang WANG Hong TAN Jie Hua LI Yin Ping ZHONG College of Polymer Science Engineering Sichuan University Chengdu College of Chemistry & Environment Protection Engineering Southwest University for Nationalities Chengdu Key Laboratory of Bio-resources Eco-environment 《中国化学快报》2006,(11)
In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts (QAS), lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart. 相似文献
957.
PENG Jingdong LIU Shaopu LIU Zhongfang & SHI Yan College of Chemistry Chemical Engineering Southwest China Normal University Chongqing China 《中国科学B辑(英文版)》2006,(5)
In a pH 3.6―5.0 HAc-NaAc buffer solution, when sodium tanshinon ⅡA silate (STSⅡA) reacts with La(Ⅲ) to form a chelate, the resonance Rayleigh scattering (RRS) intensity can be en-hanced greatly and a new RRS spectrum will appear. The maximum RRS peak is located at 306 nm and the RRS intensity is proportional to the concentration of STSⅡA in a certain range. The method is very sensitive and the detection limit for STSⅡA (3σ/K) is 82.12 ng·mL?1. The optimum reaction condi-tions and the effect of coexisting substances have been investigated. A new, simple and fast method for the determination of STSⅡA based on RRS method is developed. It can be applied to the deter-mination of STSⅡA in the synthesis samples and Nuoxinkang injection. Combined with infrared ab-sorption and NMR spectra, the structure of the chelate and the reasons of RRS enhancement are also discussed. 相似文献
958.
SOLIMAN Ahmed Youssef ATTIA Ibrahim Abd El-Mogoud SALEM Moneer Abdu Ibrahim SOLIMAN El-SayedAhmed GABER Adel Mohy El-Deen 《中国化学》1996,14(5):437-446
Science Department, Faculty of Teachers, P.O.Box 2313, Al Hasa, 31982, Saudi Arabia Faculty of Engineering, Ain Shames University, EgyptChemistry Department, Faculty of Science, Ain Shames University, Egypt 相似文献
959.
Feifei Sun Yunfeng Geng Shunhe ZhongCollege of Chemical Engineering Technology State Key Laboratory of Cl Chemistry Technology Tianjin University Tianjin China 《天然气化学杂志》2002,(Z2)
Heteropolyacid, the most popular catalyst for the direct oxidation of isobutane, exhibits high catalytic activity, poor thermal stability and a short lifetime. Therefore, the catalyst requires further research to improve its performance. Catalysts composed of mixed oxides (V2O5, P2O5, or MoO3) supported on silica were prepared by the sol-gel method to catalyze the reaction. Results of XRD, IR, and BET corroborated that the mixed oxides were dispersed homogeneously on the surface of support. The activity of lattice oxygen in the catalysts was studied by TPR, and the chemisorption property of isobutane on the surface of the catalysts was investigated by the TPD method. H2-TPR of the catalysts revealed that the lattice oxygen of the vanadium-based catalysts is more active than that of the molybdenum-based catalysts. The redox property of V or Mo species is slightly affected by other compositions of the series catalysts. The TPD curves illustrate that there are two kinds of adsorptive species of isobutane on 相似文献
960.
The luminescence properties of aluminate sodalite Ca8[Al12024](WO4)2 (CAW) undoped and doped with Th^3 are reported and discussed. At room temperature the emission of tetrahedral WO4^2- in CAW showed an abnormally small Stokes shift (9060 cm^-1), which is related to the crystal structure of CAW. A strong absorption band in the excitation spectrum of the Th^3 -activated CAW is ascribed to the absorption of the charge transfer state Th^4 -W^5 , into which the excitation resulted in the efficient emission from the ^5D4 level of Tb^3 , but not from the ^5D3 level. 相似文献