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101.
ZHANG ZhaoXiang ZHANG XiaoWei & LI Feng Key Laboratory of Eco-Chemical Engineering Ministry of Education College of Chemistry Molecular Engineering Qingdao University of Science Technology Qingdao China School of Science Qingdao Technological University Qingdao China 《中国科学:化学》2010,(5)
A novel method has been developed by integration of multi-concentration and two-dimensional(2D) capillary electrophoresis(CE) for simultaneous enhancement of detection sensitivity and separation power in complex samples.Capillary zone electrophoresis(CZE) was used as the first dimension separation according to mobilities,from which the effluent fractions were further analyzed by micellar electrokinetic capillary chromatography(MEKC) acting as the second dimension.Cation-selective exhaustive injection(CSEI) ... 相似文献
102.
System calibration, which usually involves complicated and time-consuming procedures, is crucial for any three-dimensional (3D) shape measurement system based on vision. A novel improved method is proposed for accurate calibration of such a measurement system. The system accuracy is improved with considering the nonlinear measurement error created by the difference between the system model and real measurement environment. We use Levenberg-Marquardt optimization algorithm to compensate the error and get a good result. The improved method has a 50% improvement of re-projection accuracy compared with our previous method. The measurement accuracy is maintained well within 1.5% of the overall measurement depth range. 相似文献
103.
Zheng Wang Wei Zhang Feng Tao Kai Ge Meng Long Yi Xi Ying Li Qing Jiang 《中国化学快报》2011,22(8):1001-1004
Two novel copolymers based on squaraine and fluorine units have been synthesized through palladium catalyzed Suzuki coupling reaction and Sonogashira coupling reaction,respectively.The structures and properties of the two copolymers were characterized by FT-IR.NMR,UV-vis absorbance(Abs),gel permeation chromatography(GPC),thermal gravimetric analysis (TGA),differential scanning calorimetry(DSC) and cyclic voltammetry(CV).The solution absorption spectrums of P1 and P2 show two distinct absorption bands,one locates at 300-500 nm and the other at 600-800 nm.The absorption spectrums of P1 and P2 in films are broadened obviously and the spectral responses are extended up to 900 nm.Thermal gravimetric analysis demonstrates that the polymers are stable.Cyclic voltammetry experiment shows that the band gaps of the copolymers are 1.65 eV and 1.67 eV. respectively,suggesting their potential for applications as solar cells materials. 相似文献
104.
A novel approach to the synthesis of 4-phenylethynylphthalic anhydride has been described.The target compound was synthesized by Pd/Cu catalyzed Sonogashira coupling reaction between phenylacetylene and 4-bromophthalic acid which was for the first time employed as start material,followed by dehydration of 4-phenylethynylphthalic acid.Compared with traditional synthetic routes,this method provides several advantages such as readily available raw materials,convenient manipulation and high yield.The product... 相似文献
105.
Jinxia Gua b Zhipeng Baib Weifang Lib Liping Wua Aixia Liuc Haiyan Dongd Yiyang Xiec a Tianjin Institute of Urban Construction Tianjin China b State Environmental Protection Key Laboratory of Urban Ambient Air Particulate Matter Pollution Prevention Control College of Environmental Science Engineering Nankai University Tianjin China c Tianjin Institute of Meteorological Instruments Tianjin China d Tianjin Environmental Monitoring Central Station Tianjin China 《中国颗粒学报》2011,(3)
PM2.5 samples for 24 h were collected during winter in Tianjin,China. The ambient mass concentration and chemical composition of the PM2.5 were determined. Ionic species were analyzed by ion chromatog-raphy,while carbonaceous species were determined with the IMPROVE thermal optical reectance(TOR) method,and inorganic elements were measured by inductively coupled plasma-atomic emission spec-trometer. The daily PM2.5 mass concentrations ranged from 48.2 to 319.2 g/m3 with an arithmetic average of 144.6 g/m3. ... 相似文献
106.
ZHAO YuXin YI ShiHe TIAN LiFeng HE Lin & CHENG ZhongYu College of Aerospace Material Engineering National University of Defense Technology Changsha China 《中国科学G辑(英文版)》2008,51(8):1134-1143
Flow visualization of supersonic mixing layer has been studied based on the high spatiotemporal resolution Nano-based Planar Laser Scattering(NPLS) method in SML-1 wind tunnel. The corresponding images distinctly reproduced the flow structure of laminar,transitional and turbulent region,with which the fractal measurement can be implemented. Two methods of measuring fractal dimension were introduced and compared. The fractal dimension of the transitional region and the fully developing turbulence region of supersonic mixing layer were measured based on the box-counting method. In the transitional region,the fractal dimension will increase with turbulent intensity. In the fully developing turbulent region,the fractal dimension will not vary apparently for different flow structures,which em-bodies the self-similarity of supersonic turbulence. 相似文献
107.
Yazicioglu Y Royston TJ Spohnholtz T Martin B Loth F Bassiouny HS 《The Journal of the Acoustical Society of America》2005,118(2):1193-1209
The vibration of a thin-walled cylindrical, compliant viscoelastic tube with internal turbulent flow due to an axisymmetric constriction is studied theoretically and experimentally. Vibration of the tube is considered with internal fluid coupling only, and with coupling to internal-flowing fluid and external stagnant fluid or external tissue-like viscoelastic material. The theoretical analysis includes the adaptation of a model for turbulence in the internal fluid and its vibratory excitation of and interaction with the tube wall and surrounding viscoelastic medium. Analytical predictions are compared with experimental measurements conducted on a flow model system using laser Doppler vibrometry to measure tube vibration and the vibration of the surrounding viscoelastic medium. Fluid pressure within the tube was measured with miniature hydrophones. Discrepancies between theory and experiment, as well as the coupled nature of the fluid-structure interaction, are described. This study is relevant to and may lead to further insight into the patency and mechanisms of vascular failure, as well as diagnostic techniques utilizing noninvasive acoustic measurements. 相似文献
108.
109.
Gordeev SN Zhukov AA de Groot PA Jansen AG Gagnon R Taillefer L 《Physical review letters》2000,85(21):4594-4597
We report on transport measurements of YBa 2Cu 3O (7-delta) single crystals with different oxygen contents in the geometry B, J ||ab (J perpendicularB). Our data show that the vortices become confined between the Cu-O planes below a well-defined temperature at which the effective size 2xi of the vortex core is approximately equal to the period of the Cu-O layers. This confinement strongly increases the vortex liquid freezing temperature. A new melting line is found separating a vortex liquid and a smectic phase, which shows an oscillatory field dependence reflecting differences between commensurate and incommensurate smectic states. 相似文献
110.
WANG Chun-yan ZHANG Yu-jing College of Animal Science Veterinary Medicine Jilin University Changchun P. R. China 《高等学校化学研究》2011,(2)
The lack of efficient and non-toxic gene delivery, preferably with non-viral DNA vectors, is generally regarded as a major limitation for gene therapy. In this study, a wheat histone H4 gene was cloned from Triticum aestivum, sequenced, modified and expressed in E. coli. The wheat histone H4 gene and reconstructed H4TL gene encoded wheat histone H4 and a recombinant protein of 141 amino acids with an approximate molecular weight of 15500. Gel electrophoresis mobility shift assays demonstrated that the purif... 相似文献