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991.
毛细管电色谱研究进展 总被引:7,自引:2,他引:7
毛细管电色谱是一种新兴的具有高效,高选择性的微分离技术。本文评述了毛细管电色说的发展状况和相关的技术,并对其发展前景进行了展望,引用文献24篇 。 相似文献
992.
兖州高硫煤的加氢热解脱硫及脱硫动力学 总被引:5,自引:1,他引:5
在加压热天平上,考察了氢气和氮扬气氛下高硫煤的热解脱硫。利用气相色谱在线分析研究了硫化氢氢气的逸出规律。结果表明,加氢热解比氮气下的热解有着更显著的脱友作用,脱硫率可达90%以上。而且加氢热解下65%的脱除硫转化为气相硫化氢,而氮气下热解是有80%的硫转化为液相。 相似文献
993.
Nanoscale organization of the pathogen receptor DC-SIGN mapped by single-molecule high-resolution fluorescence microscopy. 总被引:3,自引:0,他引:3
Bärbel I. de Bakker Dr. Frank de Lange Dr. Alessandra Cambi Dr. Jeroen P. Korterik Erik M. H. P. van Dijk Dr. Niek F. van Hulst Prof. Carl G. Figdor Prof. Maria F. Garcia‐Parajo Prof. 《Chemphyschem》2007,8(10):1473-1480
DC-SIGN, a C-type lectin exclusively expressed on dendritic cells (DCs), plays an important role in pathogen recognition by binding with high affinity to a large variety of microorganisms. Recent experimental evidence points to a direct relation between the function of DC-SIGN as a viral receptor and its spatial arrangement on the plasma membrane. We have investigated the nanoscale organization of fluorescently labeled DC-SIGN on intact isolated DCs by means of near-field scanning optical microscopy (NSOM) combined with single-molecule detection. Fluorescence spots of different intensity and size have been directly visualized by optical means with a spatial resolution of less than 100 nm. Intensity- and size-distribution histograms of the DC-SIGN fluorescent spots confirm that approximately 80 % of the receptors are organized in nanosized domains randomly distributed on the cell membrane. Intensity-size correlation analysis revealed remarkable heterogeneity in the molecular packing density of the domains. Furthermore, we have mapped the intermolecular organization within a dense cluster by means of sequential NSOM imaging combined with discrete single-molecule photobleaching. In this way we have determined the spatial coordinates of 13 different individual dyes, with a localization accuracy of 6 nm. Our experimental observations are all consistent with an arrangement of DC-SIGN designed to maximize its chances of binding to a wide range of microorganisms. Our data also illustrate the potential of NSOM as an ultrasensitive, high-resolution technique to probe nanometer-scale organization of molecules on the cell membrane. 相似文献
994.
995.
Iron speciation related to color of Jurassic sedimentary rocks in Turpan Basin, northwest China 总被引:1,自引:0,他引:1
Guodong Zheng Bihong Fu Yi Duan Qi Wang M. Matsuo B. Takano 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(2):421-427
Mesozoic-Cenozoic reddish and green beds are widely distributed in northwest China. Mössbauer spectroscopy revealed that the composition of iron species varies with color in the middle-upper Jurassic sedimentary rocks from the Turpan Basin. Three main kinds of iron species were identified: (1) ferric iron of hematite (hem-Fe3+), (2) paramagnetic ferric iron (para-Fe3+), and (3) paramagnetic ferrous iron (para-Fe2+). Pyrite iron (pyr-Fe2+) was revealed only in a few samples. In general, there is a direct correlation between rock color, iron species and total iron content, however, in detail, this relationship is more complicated. The reddish rocks contain higher contents of total iron and hem-Fe3+, whereas the gray rocks contain much more para-Fe2+. However, relatively low hematite content cannot give red color to rocks, probably due to suppression by other pigments such as organic matter in black or chlorite in green. The dark or green rocks normally contain either only paramagnetic Fe2+ and paramagnetic Fe3+ species or these two species associated with hematite Fe3+, but the relative content of hematite species is lower. The variations of different iron species control lithological properties such as color and also may reflect the sedimentary conditions. Moreover, iron speciation in these rocks is one of the main factors, which result the color features of rocks in remote sensing imagery.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
996.
Ionic liquids are a new kind of room-temperature molten organic salts. It can be used as solvents in the organic/polymeric syntheses, and some of them are called "green" solvents because of its recyclability1. Ionic liquids possess the superior properties, such as thermal stability up to 200(C, involatility and re-designability(for both cation and anion). The ionic liquid employed in this work is [bmim] [PF6]- ( butylmethylimidazolium hexafluorophosphate ) which is immiscible with water and h… 相似文献
997.
ZnCuCoAlNO3型四元水滑石及其多氧阴离子柱撑物的合成与催化氧化性能 总被引:4,自引:0,他引:4
Anionic clay, ZnCuCoAlNO3 and its polyoxometalate intercalates were synthesized, and were characterized by XRD, IR, 31PMAS NMR, DTA and elemental analysis. The pillared products are found to be effective catalysts for oxidation of cyclohexene with molecular oxygen under mild reaction conditions 相似文献
998.
999.
热活化延迟荧光(TADF)聚合物,不仅具有小分子TADF材料高的激子利用效率特性,而且还具备分子多样性好、可溶液加工、低成本、以及易实现大面积柔性器件等诸多优势,在近几年受到广泛的关注并展现了良好的应用前景。本文从TADF聚合物分子设计原理、器件结构及发光机理出发,依据TADF聚合物的构筑方法不同,概括了其结构设计策略,详述了各种类型TADF聚合物的分子结构和光电性能及其在有机电致发光器件领域应用的研究进展,最后探讨了TADF聚合物存在的问题,并展望了其发展前景。 相似文献
1000.
Hong She Wang Jun E. Zeng 《中国化学快报》2007,18(12):1447-1450
Synthesis of symmetrical diaryl sulfoxides from arenes and thionyl chloride in the presence of a catalytic amount of iodine at room temperature under solvent-free conditions is described.Mild reaction conditions,easy workup,high yield,and easily available catalyst are important features of this method. 相似文献