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以非离子表面活性剂四氧乙烯基正十二烷基醚与氯铂酸水溶液构建层状溶致液晶, 通过电沉积技术制备了金属铂纳米线. 分别采用偏光显微镜、小角X射线散射对液晶进行结构分析, 通过透射电镜和能量弥散X射线谱分析观测产物形貌并确定其组成. 结果表明, 相对于饱和甘汞电极, 沉积电势在0.05~0.20 V范围内, 金属铂沿表面活性剂双分子层膜生长, 反应前后液晶相的长程周期性结构无明显变化; 在0.10 V沉积电势下, 随反应时间从960 s延长至3840 s, 去除表面活性剂后沉积产物分别为层状纳米粒子、层状纳米线以及长度达十几微米且致密的纳米线. 讨论了层状液晶对沉积产物的结构导向作用. 相似文献
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有序纳米结构材料是一类具有广泛应用前景的新材料,在分离、催化、传感器等领域的应用潜力巨大。近年来,利用溶致液晶模板合成纳米结构颗粒和薄膜材料的研究取得了一系列重要进展,包括新纳米结构金属和半导体材料的合成、由过渡金属水合物与表面活性剂构建的新液晶体系、溶致液晶与其它模板结合制备具有多级孔结构的新材料、影响液晶体系及纳米结构材料有序性与稳定性的关键因素、以及纳米结构形成机理等方面的内容。本文就上述几个方面的近期研究成果进行了总结与综述,并展望了利用溶致液晶模板合成纳米结构材料需要进一步深入开展的内容,有助于化学、化学工程和材料科学等领域的相关研究工作。 相似文献
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磺酸型双子表面活性剂的溶致液晶结构研究 总被引:2,自引:0,他引:2
合成了一种磺酸型双子表面活性剂6,6 -(丁基-1,4-二基双氧)双(3-壬基苯磺酸)(9BA-4-9BA), 利用偏光显微镜和X射线衍射分析仪研究了其在水溶液和乙酸乙酯溶液中的溶致液晶结构变化. 结果表明, 9BA-4-9BA在两种溶剂及其混合溶剂中均可出现溶致液晶态结构, 并且双子表面活性剂的溶致液晶相态与溶液浓度和溶剂种类密切相关. 随着浓度增加, 9BA-4-9BA水溶液溶致液晶结构由立方相经由片层立方相转变为层状液晶相, 乙酸乙酯溶液中主要以层状液晶相存在. 相似文献
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近年来氧化铝模板电沉积功能纳米材料的技术得到了较快的发展.综述了氧化铝模板电沉积功能纳米材料的最新研究方法,介绍了国内外氧化铝模板电沉积法在制备功能纳米材料上的应用. 相似文献
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以铂微电极法测定了在SDS/n-C5H11OH/H2O溶致液晶中SDS(十二烷基硫酸钠)分子的扩散系数.结果表明,恒定质量比SDS/n-C5H11OH条件下,溶致液晶中SDS分子的扩散系数随体系中水含量的增加而增加;恒定质量比SDS/H2O,溶致液晶中SDS分子的扩散系数随正戊醇含量的增加而增加;恒定质量比H2O/n-C5H11OH ,溶致液晶中SDS分子的扩散系数随SDS含量的增加而降低.六角状液晶中SDS分子的扩散系数比层状液晶中SDS分子的扩散系数低约1个数量级,而比W/O、O/W胶束的扩散系数低3~5个数量级. 相似文献
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聚酯酰胺的合成及表征 总被引:1,自引:0,他引:1
用两种方法合成了聚酯酰胺(PEA)共聚物.一种是两步法,即先合成对苯二甲酸乙醇酰胺(BAET)单体,然后与对苯二甲酸乙二酯(BHET)共缩聚;另一种是一步法.即在酯交换反应中直接添加乙醇胺(EA).两种方法制得的聚酯酰胺(PEA)共聚物测试证明了为产物,并分析了合成中的化学反应. 相似文献
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A non-linear least-squares regression program is described which is suitable for PC-compatible microcomputers. The program is written in GWBASIC, but compiled to run with the Intel 8087 fast numeric processor. Subroutines which simulate functions are compiled separately from the main program. Parameters are optimized by a Gauss-Newton-Marquardt algorithm which can be provided with either analytically or numerically calculated partial derivatives. Multi-component potentiometric titrations are simulated and parameters optimized by using analytical derivatives. Spectrophotometric titrations are also simulated, but absorptivities are optimized by linear regression while stability constants are optimized non-linearly by using numerical derivatives. Provision is made for "global analysis" of parameters. The experimental points can be displayed on screen, along with the "best" fit and the speciation. The program is demonstrated here by the determination of the pK(a) values and stability constants of a hydroxypyridinone ligand and its complexes with Fe(III). 相似文献
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聚酯酰胺的合成及表征 总被引:2,自引:0,他引:2
用两种方法合成了聚酯酰胺(PEA)共聚物.一种是两步法,即先合成对苯二甲酸乙醇酰胺(BAET)单体,然后与对苯二甲酸乙二酯(BHET)共缩聚;另一种是一步法.即在酯交换反应中直接添加乙醇胺(EA).两种方法制得的聚酯酰胺(PEA)共聚物测试证明了为产物,并分析了合成中的化学反应. 相似文献
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Production of acetone-butanol-ethanol from corn mash and molasses in batch fermentation 总被引:2,自引:0,他引:2
The production of solvents from corn mash and molasses in batch fermentation usingClostridium acetobutylicum P 262 was examined. The content of saccharose of beet molasses used in experiments is determined by using the gravimetric
method (52.45% saccharose). The quantities of molasses that are used in the nutrient medium are calculated after doing the
above determination. The samples of fermentation liquid are taken within a certain time, the determination of saccharose is
done by using the same method, and all the saccharose is converted by the microorganism to organic end products. The quantitative
and qualitative determination of acetone-butanol has been made by using gas chromatography. On the other hand, using the three
isolation way, three different cultures are obtained, and with microscopic observations, the cultures obtained are of the
C.acetobutylicum genus. According to the literature values, the concentration of maximum mixed solvent formed during fermentation is about
2%. This is seen in this experiment. There is only a slight difference from this value. This difference is caused by another
organic product that is formed during fermentation. 相似文献
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John J. Mccormack Barbara A. Allen C. Nicholas Hodnett 《Journal of heterocyclic chemistry》1978,15(8):1249-1254
Quinazoline is oxidized by xanthine oxidase initially (and rapidly) to 4-hydroxyquinazoline which subsequently is oxidized more slowly to 2,4-dihydroxyquinazoline. Both oxidative reactions are inhibited strongly by allopurinol. Quinazoline is oxidized by aldehyde oxidase to 4-hydroxyquinazoline but within a short time (3–5 minutes) the reaction ceases; the proposal that cessation of reaction is due to product inhibition is rendered untenable by our observation that 4-hydroxyquinazoline is rapidly oxidized by aldehyde oxidase to 2,4-dihydroxyquinazoline. Preincubation of aldehyde oxidase with quinazoline results in complete inhibition of the ability of the enzyme to oxidize 4-hydroxyquinazoline and the standard substrate N-methylnicotinamide. It appears therefore that quinazoline is able to react with aldehyde oxidase and inactivate it. Quinoxaline and 2-hydroxyquinoxaline are not oxidized by xanthine oxidase but are converted by aldehyde oxidase to 2,3-dihydroxyquinoxaline; all oxidations mediated by aldehyde oxidase are inhibited completely by menadione. 相似文献
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Relaxation processes of surfactant adsorption and surface tension, which are characterized by two specific relaxation times, are theoretically investigated. We are dealing with fluid interfaces and small initial deviations from equilibrium. For surfactant concentrations below the critical micellization concentration (CMC), we consider adsorption under mixed barrier-diffusion control. General analytical expressions are derived, which are convenient for both numerical computations and asymptotic analysis. Series expansions for the short- and long-time limit are derived. The results imply that the short-time asymptotics is controlled by the adsorption barrier, whereas the long-time asymptotics is always dominated by diffusion. Furthermore, for surfactant concentrations above the CMC, adsorption under mixed micellization-diffusion control is considered. Again, a general analytical expression is derived for the relaxation of surfactant adsorption and surface tension, whose long- and short-time asymptotics are deduced. The derived equations show that at the short times the relaxation is completely controlled by the diffusion, whereas the long-time asymptotics is affected by both demicellization and diffusion. The micellar effect is manifested as an exponential (rather than square-root) decay of the perturbation. The derived expressions are applied to process available experimental data for the nonionic surfactant Triton X-100 and to determine the respective demicellization rate constant. 相似文献
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Rapid determination of lead and cadmium in biological fluids by electrothermal atomic absorption spectrometry using Zeeman correction 总被引:2,自引:0,他引:2
Procedures for the electrothermal atomic absorption spectrometric determination of lead and cadmium in urine, serum and blood are developed. For serum and blood, the samples are diluted by incorporating 0.015% (w/v) Triton X-100 and 0.1% (w/v) ammonium dihydrogenphosphate to the solutions, which are then introduced directly into the furnace. A solution containing 15% (w/v) hydrogen peroxide and 0.65% (w/v) nitric acid is also introduced into the atomizer by means of a separate injection. Zeeman-based correction is recommended. Both conventional and fast-heating programs are discussed. Calibration is carried out using the standard additions method. The reliability of the procedures is checked by analyzing three certified reference materials and by recovery studies. 相似文献
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Formation and Processing of UV Photoproducts: Effects of DNA Sequence and Chromatin Environment 总被引:11,自引:0,他引:11
Gerd P. Pfeifer 《Photochemistry and photobiology》1997,65(2):270-283