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1.
H. William Bosch Sre
o D. kapin Egon Matijevi 《Colloids and surfaces. A, Physicochemical and engineering aspects》2004,250(1-3):43-50
Controlled precipitation of the diagnostic imaging agent ethyl 3,5-di(acetylamino)-2,4,6-triiodobenzoate has been used to produce fine particles of various sizes, morphologies, and degrees of crystallinity, which depended on experimental conditions. In addition, two distinct polymorphic forms of the drug have been fully characterized by single crystal X-ray diffraction studies, and evidence for a third polymorph was also observed. Some of the so prepared dry particles were coated with a thin layer of silica. 相似文献
2.
In this paper, we report the conducting and electrochemical properties of a homogeneous V2O5-SiO2 xerogel composite obtained from the simultaneous polymerization in both inorganic components (Si-O and V-O based polymers) forming an interpenetrating polymer network, where a mutual “solubility” due to cross-links and entanglements was observed. The presence of V2O5 inside the silica matrix has a strong effect on electrical conductivity; measurements showed room temperature conductivity almost 1000 times higher than what is found in the literature. In addition, the electrochemical behavior is quite similar to that found in V2O5 xerogel. Moreover, the effects of thermal treatment on the conducting and electrochemical properties were investigated. It was found that both properties were improved with no significant effect on V2O5 xerogel layered structure. 相似文献
3.
Suzanne J. Dilly Steven J. Carlisle Andrew J. Clark Andrew R. Shepherd Stephen C. Smith Paul C. Taylor Andrew Marsh 《Journal of polymer science. Part A, Polymer chemistry》2006,44(7):2248-2259
A practical and divergent synthesis of supported [1,3,5]‐triazine dendritic molecules on Wang resin, PEGA resin, SynPhase? Lanterns, and silica gel is described. The alkylamine linkers used allow derivatization with functionality for both synthetic (e.g., supported reagent and scavenger activity) and chemical biology applications. The use of supported intermediates allows differentiation of symmetric linkers without the need for protecting group chemistry. The synthetic route uses inexpensive, readily available starting materials in a straightforward and scaleable strategy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2248–2259, 2006 相似文献
4.
对国产GYQG球形硅胶施加高压水热处理并进行扩孔,制备了用于高效液相色谱法的大孔硅胶填料,考察了扩孔压力,扩孔温度和扩孔时间对平均孔径和比表面积的影响。并将产品日本SIL-3003×10^-8m硅胶进行了物理性质和孔分布的对比实验,结果表明GYQG硅胶扩孔后平均孔径为20~30nm接近日本SIL-3003×10^-8m硅前平平均孔径25nm。display structure 相似文献
5.
The phase analysis of cryolite (Na3AlF6) and sodium metasilicate (Na2SiO3) was performed by thermal analysis. The eutectic system with a region of two immiscible substances at a concentration of Na2SiO3 between 42.8 and 46.3 mol‐% was identified and the eutectic temperature determined to (886±2) °C. Based on the results of mass‐loss measurements, it was assumed that the introduced Na2SiO3 reacts with Na3AlF6 due to the formation of some nonvolatile stable compounds. The stable reaction products were identified by X‐ray diffraction analysis and IR spectroscopy of the spontaneously cooled samples, which established the formation of NaF and stable amorphous aluminosilicate compounds. 相似文献
6.
R. Leboda 《Chromatographia》1980,13(9):549-554
Summary The surface properties of complex adsorbents prepared through the pyrolysis of benzyl and n-heptyl alcohols and their mixtures
on the surface of silica gel were investigated. The reactions were carried out in an autoclave at 500°C. A series of adsorbents
having different porous structure, chemical nature of the adsorption centers and their topography were obtained. The best
resolution of different mixtures was obtained by the carbon-silica adsorbent prepared through the pyrolysis of n-heptanol. 相似文献
7.
(1)测定了醋酸十二烷基铵(DAA)在CAB-O-SIL上的吸附,其等温线属双平台或LS型[1-3,5];(2)NaCl的存在使DAA的吸附增加.但不影响其低浓度下第一平台的吸附量;HCl的存在则在全浓度范围内抑制了DAA的吸附,(3)测定了CAB-O-SIL颗粒在上述各溶液中的悬浮液的稳定性;(4)根据表面形成小胶团的吸附理论(即二步模型产)[2,3,5,],并借助电导跟踪溶液中发生的变化,满意地解释了吸附和聚沉的实验结果. 相似文献
8.
Two protocols for functionalization of glass supports with hexaethylene glycol (HEG)-linked oligonucleotides were developed.
The first method (standard amidite protocol) made use of the 2-cyanoethyl-phosphoramidite derivative of 4,4′-dimethoxytrityl-protected
HEG. This was first coupled to the support by standard solid-phase phosphoramidite chemistry followed by extension with a
thymidylic acid icosanucleotide. Stepwise addition of the linker phosphoramidite graduated at 1% (relative to the total sites
available) perstep at 50°C resulted in an optimal yield of immobilized oligonucleotides at a density of 2.24 × 1010 strands/mm2. This observed loading maximum lies well below the theoretical maximum loading owing to nonspecific adsorption of HEG on
the glass and subsequent blocking of reactive sites. Surface loadings as high as 3.73 × 1010/mm2 and of excellent sequence quality were achieved with a reverse amidite protocol. The support was first modified into a 2-cyanoethyl-N,N-diisopropylphosphoramidite analog followed by coupling with 4,4′-dimethoxytrityl-protected HEG. This protocol is conveniently
available when using a conventional DNA synthesizer. The reverse amidite protocol allowed for control of the surface loading
at values suitable for subsequent analytical applications that make use of immobilized oligonucleotides as probes for selective
hybridization of sample nucleic acids of unknown sequence and concentration. 相似文献
9.
Silica xerogels with different structures and morphology, synthesized using a sol-gel procedure, were used as a carrier of vanadium catalysts (VOCl3/AlEt2Cl) for ethylene polymerization. Two techniques of catalyst synthesis were applied: slurry impregnation and gas-phase adsorption and the relevant polymerization methods were then employed. The effect of the carrier structure and morphology on the vanadium loading in the catalysts, the catalyst’s activity and kinetic stability were investigated. 相似文献
10.
Summary Electrophoretic mobility measurements in the pH 2‐10 range are described for several commercial HPLC silica microparticles
and a laboratory-produced product. The content of metal impurities for the silicas was also determined by AAS. An acidic/hydrothermal
treatment was used to generate a more homogenous surface for some of the silicas. The zero points of charge (zpc) for both
a native and a treated silica plus several commercial HPLC silicas were compared. The electrophoretic mobility method may
be useful in predicting the utility of certain types of silica supports for chromatographic separations. 相似文献