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91.
采用溶胶凝胶法,以蔗糖和正硅酸乙酯(TEOS)为原料,草酸为TEOS水解的催化剂,制备均相碳化硅前驱体,在氩气氛和高温条件下(1 350~1 600 ℃)将碳化硅先驱体进行碳热还原,制备出高比表面积的SiC。考察了水/TEOS物质的量的比、碳/硅物质的量的比及镍盐等因素对碳化硅比表面积的影响。结果表明,当nwater/nTEOS=7.5,nC/nSi=4时,适宜的镍催化剂(nNi/nTEOS=0.005),凝胶形成的时间最短,镍盐的加入可使碳热还原温度降低200 ℃。 相似文献
92.
聚乙烯醇高含水胶固定化脲酶的研究 总被引:2,自引:0,他引:2
冷冻-部分脱水法制成的聚乙烯醇高含水胶固定化脲酶活力收率及对脲素的分解能力明显高于聚丙烯酰胺囱定化脲酶,稳定性相近;用低浓度的戊二醛后处理,提高了固定化酶的稳定性。 相似文献
93.
By use of salt elimination, the transition metal substituted oligosilanes (η5-C5Me4Et)Fe(CO)2SiMe2SiMe2Cl 1, (η5-C5Me4Et)Mo(CO)3SiMe2SiMe2Br 2, (η5-C5Me4Et)Fe(CO)2(SiMe2)6(CO)2Fe(η5-C5Me4Et) 3 and (η5-C5Me4Et)Fe(CO)2(SiMe2)6Br 4 were prepared and characterized. Compound 1 is well crystallized from pentane and its structure has been determined by X-ray diffraction analysis. 相似文献
94.
95.
以铜离子为模板的褐藻酸凝胶对铜离子的选择性富集研究 总被引:2,自引:0,他引:2
以铜离子为模板,制备了褐藻酸凝胶(Cu-alginate),通过吸附实验及过柱渗滤实验,试验了该吸附剂对铜离子的选择性吸附性能,并且采用该吸附剂富集了自来水中微量的Cu^2 ,结合原子吸收法测定了水样中Cu^2 的含量。结果表明:该吸附剂对Cu^2 有较高的选择性吸附性能,显著优于一些化学合成铜离子模板缩聚物及非铜模板褐藻酸凝胶(如Ca-alginate),非重金属离子(如K^ 、Na^ 、Ca^2 )及某些重金属离子(如Ni^2 、Cd^2 )等对Cu^2 的吸附均不产生明显干扰。用该吸附剂富集水中的微量铜离子,回收率可达97.7%。 相似文献
96.
Masahiro Murayama Ryoji Kanno Michihiko IrieShinya Ito Takayuki HataNoriyuki Sonoyama Yoji Kawamoto 《Journal of solid state chemistry》2002,168(1):140-148
The new lithium ionic conductors, thio-LISICON (LIthium SuperIonic CONductor), were found in the ternary Li2S-SiS2-Al2S3 and Li2S-SiS2-P2S5 systems. Their structures of new materials, Li4+xSi1−xAlxS4 and Li4−xSi1−xPxS4 were determined by X-ray Rietveld analysis, and the electric and electrochemical properties were studied by electronic conductivity, ac conductivity and cyclic voltammogram measurements. The structure of the host material, Li4SiS4 is related to the γ-Li3PO4-type structure, and when the Li+ interstitials or Li+ vacancies were created by the partial substitutions of Al3+ or P5+ for Si4+, large increases in conductivity occur. The solid solution member x=0.6 in Li4−xSi1−xPxS4 showed high conductivity of 6.4×10-4 S cm−1 at 27°C with negligible electronic conductivity. The new solid solution, Li4−xSi1−xPxS4, also has high electrochemical stability up to ∼5 V vs Li at room temperature. All-solid-state lithium cells were investigated using the Li3.4Si0.4P0.6S4 electrolyte, LiCoO2 cathode and In anode. 相似文献
97.
Raquel Peña-Alonso Gian Domenico Sorarù 《Journal of Sol-Gel Science and Technology》2007,43(3):313-319
The sol–gel method has been used for the synthesis of borosilicate gels from mixtures of methyltriethoxysilane (MTES) and
dimethyldiethoxysilane (DMDES) and boric acid. The use of boric acid, B(OH)3 allows the hydrolysis and condensation of hybrid silicon alkoxides without further addition of water or catalyst. The use
of difunctional silicon units, –(CH3)2SiO– promote the formation, during the sol–gel process, of linear oligomers which facilitate fiber drawing before gelation.
Gel characterization performed by FT-IR, XRD, TG-DTA and DCS analysis indicates the formation of a mixed network with incorporation
of the boron units via =B-O-Si≡ bridges. The formation of borosiloxane bonds seems favored by the presence of DMDES. SiBOC
glasses were obtained after pyrolysis of the borosilicate gels in argon atmosphere at 1000 °C. TG-DTA study indicates that
the ceramic yield decreases by increasing the amount of DMDES. Gel fibers were successfully prepared from convenient partially-aged
solutions by hand drawing. Pyrolysis of the obtained gel fibers under argon atmosphere at 1000 °C open the possibility to
produce SiBOC homogeneous glass fibers with diameter as low as 10 μm. 相似文献
98.
Allyloxy bisbenzo 16-crown-5 trimethoxysilane was first used as precursor to prepare the sol-gel-derived bisbenzo crown ether/hydroxyl-terminated silicone oil (OH-TSO) SPME coating. The coating procedure involving sol solution composition and conditioning process was presented. Compared with commercial SPME stationary phases, the new coatings showed higher extraction efficiency and therefore could provide higher sensitivity for organphosphorous pesticides (OPs). Limits of detection (LODs) were in the range of 0.003-1.0 ng/g for these OPs in food samples (honey, juice, orange and pakchoi). The optimal extraction conditions of the new coatings to OPs in these samples were investigated by adjusting extraction time, salt addition, extraction temperature, and dilution ratios of samples with distilled water by using SPME coupled with gas chromatography (GC)-flame photometric detection (FPD). The method was applied to determine the concentrations of OPs in real samples. 相似文献
99.
100.
A simple direct enzyme immunoassay for semiquantitative detec tion of antibodies is suggested. It is based on the difference
in diffusion rates in a gel for a synthetic low-mol-wt antigen and of its complexes with antibodies to be detected. Sensitivity
and specificity of the devel oped assay are equal to an ELISA method. The assay has been tested with antibodies against HIV
protein gp41 in rabbit serum. Possible applications and limitations of the method are discussed. 相似文献