共查询到19条相似文献,搜索用时 93 毫秒
1.
硅溶胶结合浇注料的流变性能研究 总被引:1,自引:0,他引:1
对高纯硅溶胶电熔莫来石细粉泥浆的流变性能研究表明:这种泥浆是存在触变结构的高浓度胶溶悬浮体系,在受较低剪切力作用时产生的是粘滞流动,总的表现符合Bingham流变方程。研究还表明:少量超细粉的加入不改变泥浆的流变模型,但能有效地改善其流变性能,不同的超细粉影响力不同,且这种改善作用有一最佳加入量(活性SiO2超细粉影响力大于活性Al2O3微粉,其最佳加入量分别为2%和10%),超过这一加入量将导致流变常数上升,使其流变性恶化。 相似文献
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溶胶—凝胶法制备SiO2膜的研究 总被引:11,自引:0,他引:11
研究了正硅酸乙酯和硅溶胶水解聚合过程中溶胶聚合物分子的生长过程。用TEOS和硅溶胶作原料。用溶胶-凝胶法制备了有载体和无体体的SiO2膜,由不同原料引起的聚合物分子的不同生长模式将引起无载体SiO2膜孔径的较大差异,用TEOS制得的无载体SiO2膜无1.7nm以上的孔,而用硅溶胶制得的SiO2膜平均孔径为7.5nm且孔径分布狭窄。用TEOS作原料可在载体α-Al2O3上制得无大孔缺陷厚约0.8μm 相似文献
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研究了正硅酸乙酯(TEOS)和硅溶胶水解聚合过程中溶胶聚合物分子的生长过程。用TEOS和硅溶胶作原料,用溶胶-凝胶法制备了有载体和无载体的SiO_2膜。由不同原料引起的聚合物分子的不同生长模式将引起无载体SiO_2膜孔径的较大差异。用TEOS制得的无载体SiO_2膜无1.7nm以上的孔,而用硅溶胶制得的SiO_2膜平均孔径为7.5nm,且孔径分布狭窄。用TEOS作原料可在载体α-Al_2O_3上制得无大孔缺陷厚约0.8μm的SiO_2膜,膜的纯氮气渗透表现出Knudsen扩散特征。制膜时涂膜-干燥循环不少于三次才可避免产生大孔缺陷。 相似文献
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CALIXE[4]ARENE AS A TEMPLATE FOR CONTROLLING REGIOCHEMISTRY OF PHOTODIMERIZATION OF 9-SUBSTITUTED AN
《感光科学与光化学》1995,(2)
CALIXE[4]ARENEASATEMPLATEFORCONTROLLINGREGIOCHEMISTRYOFPHOTODIMERIZATIONOF9-SUBSTITUTEDANTHRACENELIYI;TONGZHEN-HE(CHEN-HOTUNG... 相似文献
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模糊综合评判模型在高新技术企业评价中的应用 总被引:1,自引:0,他引:1
模糊综合评判模型在高新技术企业评价中的应用徐杰,刘光富APPLICATIONOFMODELWITHFUZZYSYNTHETICALJUDGEINVALUATIONOFHIGH-NEWENTERPRISES高新技术企业做为经济生活中一支新生力量,在各级... 相似文献
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通过聚丙烯树脂中工稳定性及聚丙烯薄片烘箱老化试验,比较了烷基亚磷酸酯WESTON619与芳基亚磷酸酯IRGATOS168对PP热氧稳定性作用的影响,结果表明:在与酚类抗氧剂1010并用时,WESTON619对PP的长期热氧稳定性有明显的协同效应,而IRGATOS168则可有效地抑制PP的热氧降解。 相似文献
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乙二醇生产废水水质分析研究 总被引:2,自引:0,他引:2
通过乙二醇废水进行了定量分析了研究,确定了废水中主要污染组分及其含量,分析了废水中COD、BOD与TOC及MEG、DEG间的相互关系,提出了一新的废水中乙二醇、二乙二醇的分析方法。 相似文献
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Y-TYPE ZEOLITES AS MICRO-REACTORS FOR PHOTOCHEMICAL PREPARATION OF LARGE-RING COMPOUNDS 总被引:1,自引:0,他引:1
《感光科学与光化学》1996,(1)
Y-TYPEZEOLITESASMICRO-REACTORSFORPHOTOCHEMICALPREPARATIONOFLARGE-RINGCOMPOUNDS¥TONGZhenhe;(TUNGChenho);WULizhu(InstituteofPho... 相似文献
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以Ba(OH)2.8H2O,Al(NO3)3.9H2O,TEOS为原料,采用溶胶-凝胶法制备BaO-Al2O3-SiO2三元系粉末,研究了不同因素对生成稳定溶胶和胶化时间的影响,用TG-DTA,XRD研究了溶胶-凝胶的热处理过程,用TEM观察了粉体的粒径。 相似文献
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Solid state thermo-mechanical properties, as well as low and large strain mechanical behaviour, of epoxy composites filled with sub-micron pyrogenic silica are discussed in this paper. The reinforcement mechanisms involved are investigated. Two distinct series of pyrogenic silica were used: hydrophilic silica with various specific surface areas and silica grafted with various organo-modifications. Furthermore, two series of networks, having either a high or low crosslink density, and resulting thus either in glassy or rubbery materials at room temperature, were considered. Dynamic mechanical analysis, uniaxial tensile tests and fracture mechanic tests were performed.All our results showed that pyrogenic silica leads to an improvement of network mechanical properties both in the glassy and rubbery states. The simultaneous increase of stiffness and toughness was observed, demonstrating the great potential of pyrogenic silica for the reinforcement of thermosetting systems. This exceptional behaviour has been interpreted in terms of the interactions and morphology developed. 相似文献
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Effects of densified silica fume on microstructure and compressive strength of blended cement pastes 总被引:2,自引:0,他引:2
Ji Yajun 《Cement and Concrete Research》2003,33(10):1543-1548
Some experimental investigations on the microstructure and compressive strength development of silica fume blended cement pastes are presented in this paper. The silica fume replacement varies from 0% to 20% by weight and the water/binder ratio (w/b) is 0.4. The pore structure by mercury intrusion porosimetry (MIP), the micromorphology by scanning electron microscopy (SEM) and the compressive strength at 3, 7, 14, 28, 56 and 90 days have been studied. The test results indicate that the improvements on both microstructure and mechanical properties of hardened cement pastes by silica fume replacement are not effective due to the agglomeration of silica fume particles. The unreacted silica fume remained in cement pastes, the threshold diameter was not reduced and the increase in compressive strength was insignificant up to 28 days. It is suggested that the proper measures should be taken to disperse silica fume agglomeration to make it more effective on improving the properties of materials. 相似文献
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The fouling potential of the negatively charged silica sol in electrodialysis (ED) by adsorption on the surface of an anion
exchange membrane was investigated. Since the fouling potential is related to the physical and electrochemical properties
of the silica sol and anion exchange membranes, it is important to characterize the properties of silica sol and membranes.
The surface charge of silica sol was investigated by the electrophoretic mobility and its isoelectric point was determined
as pH 3. The commercial anion exchange membranes were characterized in terms of exchange capacity, water content, the zeta
potential and the electrochemical properties of the membranes using impedance spectroscopy to predict the effects on the electrodialysis
performances. Among the characterized properties, exchange capacity and some electrochemical properties of the anion exchange
membranes were rather improved after ED experiments. In the electrodialysis of solution containing silica sol, deposition
of the silica sol did not decrease the desalting performance of the anion exchange membranes because of loosely packed cake
layer on the membrane surface. 相似文献
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Leny Mathew 《Polymer-Plastics Technology and Engineering》2013,52(1):75-81
Nano silica was synthesized by acid hydrolysis of sodium silicate using diluted hydrochloric acid. This synthetic nanosilica was used in place of hydrated silica in a HRH (hexamethylenetetramine, resorcinol and silica) bonding system for acrylonitrile butadiene rubber–nylon-6 short fiber composite. Nanosilica was also used as a reinforcing filler in acrylonitrile butadiene rubber–nylon-6 short fiber hybrid composite. Cure characteristic and mechanical properties of the hybrid composites were evaluated. Minimum torque, maximum torque, and cure time of the hybrid composites increased with silica loading. Cure rate increased with fiber loading and decreased with silica content. Scorch time also decreased with fiber loading and silica content. Volume fraction of rubber in a solvent-swollen sample increased with nanosilica. The efficiency of the HRH dry bonding system was improved in the presence of nanosilica. Nanosilica in the rubber composites also improved the tensile strength, modulus, and tear strength better than the conventional silica composites. Abrasion loss, hardness, resilience, and compression set properties were also better for the nano silica composites. The composites showed anisotropy in mechanical properties. 相似文献
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The silica aerogel with high specific surface area and large pore volume was successfully synthesized using oil shale ash (OSA) via ambient pressure drying. The oil shale ash was burned and leached by sulfuric acid solution, and then was extracted using sodium hydroxide solution to produce a sodium silicate solution. The solution was neutralized with sulfuric acid solution to form a silica gel. After washing with water, the solvent exchange with n-hexane, and the surface modification with hexamethyldisilazane (HMDZ), the aged gel was dried by fluidization technique and also using a furnace to yield silica aerogels. The physical and textural properties of the resultant silica aerogels were investigated and discussed. The results have been compared with silica aerogel powders dried in a furnace. From the results, it is clear that the properties of silica powders obtained in fluidized bed are superior to that of powders dried in the furnace. Using fluidization technique, it could produce silica aerogel powders with low tapping density of 0.0775 g/cm3, high specific surface area (789 m2/g) and cumulative pore volume of 2.77 cm3/g. 相似文献