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水体系层状液晶已有较长的研究历史,非水层状液晶则是近年来才得发展.本文以层状液晶的相行为和~2H NMR测量,研究以极性有机物甘油代替水为溶剂后,对十二烷基硫酸钠/正癸醇/溶剂体系层状液晶稳定性的影响。1 实验试剂C_(12)H_(25)SO_4Na(SDS),正癸醇(C_(10)H_(21)OH,简为C_(10)OH),甘油(简为Gly)均同文献,水为二次蒸馏水.氚代物SDS_(-d25)和C_(10)OH_(-d21)均出自Cambridge Isotopes. 层状液晶单相区域的确定和~2H NMR测量见文献[92]. 相似文献
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非水层状液晶的稳定性与相行为 总被引:3,自引:1,他引:3
水体系层状液晶已研究较久,非水层状液晶则是近十年来才得到发展。本文以层状液晶的相行为和~2H NMR测量,研究并比较了非水层状液晶十二烷基硫酸钠/正癸醇溶剂以甘油或甲酰胺为溶剂时体系的结构与稳定性。 表面活性剂十二烷基硫酸钠(BDH,简写SDS)经无水乙醇重结晶两次提纯。用铂环法测 相似文献
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Zhen-zhong Yang De-lu Zhao Polymer Physics Laboratory Institute of Chemistry Chinese Academy of Sciences Beijing China 《高分子科学》2000,(1):33-38
The phase inversion emulsification technique (PIET) is an effective physical method for preparing waterbornedispersions of polymer resins. Some results concerning the preparation of bisphenol A epoxy resin waterborne dispersions byPIET in our laboratory were summarized. Electrical properties, rheological behavior and morphological evolution duringphase inversion progress were systematically characterized. The effects of the emulsifier concentration and emulsificationtemperature on phase inversion progress and the structural features of the waterborne particles were studied as well. Thedeformation and break up of water drops in a shear field were analyzed in terms of micro-rheology, while the interaction andcoalescence dynamics of water drops were discussed in terms of DLVO theory and Smoluchowski effective collision theory,respectively. Based on the experimental results and theoretical analysis, a physical model of phase inversion progress wassuggested, by which the effects of the parameters on phase inversion progress and the structural features of the waterborneparticles were interpreted and predicted. 相似文献
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Wei-xiaTu Bao-linHe Han-fanLiu Xue-lanLuo XunLiang 《高分子科学》2005,(2):211-217
Catalytic properties of polymer-stabilized colloidal metal nanoparticles synthesized by microwave irradiation were studied in the selective hydrogenation of unsaturated aldehydes, o-chloronitrobenzene and the hydrogenation of alkenes. The results show that nanosized metal particles synthesized by microwave irradiation have similar catalytic performance in selective hydrogenation of unsaturated aldehydes, better selectivity to o-chloroaniline in hydrogenation of o-chloronitrobenzene and higher catalytic activities in hydrogenation of alkenes, compared with metal clusters prepared by conventional heating. The same apparent activation energy (Ea = 29 kJ mol^-1) for hydrogenation of 1-heptene catalyzed with platinum nanoparticles prepared by both heating modes implied that the reaction followed the same mechanism. 相似文献
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Wei-xia Tu~ 《高分子科学》2008,(1):23-29
Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the int... 相似文献
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有机金属化学汽相沉积(MO-CVD)技术是一种新型薄膜材料制备技术,它优于目前通常采用的一般CVD和物理方法[1]。主要优点:采用金属有机化合物为物质源,选择的范围比较大,其中含有易断裂的M-C键,易发生气相热分解氧化反应,成膜温度比较低,反应副产物仅有易挥发的碳氢化合物,使成膜环境无污染,易获得优质膜。因该技术是化学成膜,排除了物理方法中固有的不易控制化学计量的问题,易获得优质膜层。 相似文献
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Yi-jun Huang Guo-rong Qi Guan-xi Chen Department of Polymer Science Engineering Zhejiang University Hangzhou China 《高分子科学》2002,(5):453-459
Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complexas the catalyst was carried out. The structure of random copolymers was confirmed by ~(13)C-NMR and IR spectra. ~1H-NMRanalysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecularweight copolymers with various EO content were obtained and their values of molecular weigh distribution (MWD) fell inthe range of 1.21-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO + PO toinitiator moles used. The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition. 相似文献
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由于金属、半导体纳米微粒在光物理、光化学、光催化等方面具有突出的性能,因此如何将金属、半导体纳米微粒通过某些方式构建成某些薄膜材料,对实现纳米微粒在分子器件和光电器件方面的应用具有重要的意义.本文以制备方法为主线,介绍了几种构建金属、半导体纳米微粒薄膜的基本方法,对其中一些重要的问题进行了比较详细的讨论. 相似文献
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在盐酸和硫酸介质中,研究了汞阴极电解还原和液态Zn-Hg齐还原制备U(Ⅲ)的实验方法,比较了不同介质、酸度、铀浓度和电解时间对U(Ⅲ)还原率的影响,获得了用电解法定量还原制备U(Ⅲ)的最佳条件。经对U(Ⅲ)在空气和氮气中稳定性的测定,得出U(Ⅲ)在空气中的氧化速率呈一级反应。 相似文献
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研究螯合萃取和协同萃取机理的两相滳定法 总被引:1,自引:0,他引:1
本文用严格而简洁的方法导出用两相滴定法研究螯合萃取和协同萃取机理的理论公式。用两相滴定法研究了1-苯基-3-甲基-4-苯甲酰基吡唑啉酮-5(HPZL)的苯溶液对锌离子的萃取机理以及HPZL和TBP(磷酸三丁酯)的苯溶液对锌离子的协同萃取机理,证明这个方法得到的结果是可靠的。对两相滴定法的优缺点和适用范围进行了讨论。 相似文献
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Abstract— Enzymes can provide well defined functional targets for determining the availability and reaction characteristics of light sensitive probes. Trypsin and chymotrypsin are inhibited by flash photolysis with a photoprobe, 4-fluoro-3-nitrophenylazide (FNPA). Inhibition is competitive in the dark, and non-competitive (irreversible) following photolysis of the FNPA enzyme solution. Photoinactivation is dependent upon the concentration of FNPA, the flash rate, and the time of photolysis. The enzymes can be protected from photolytic inactivation with FNPA if photolysis is carried out in the presence of 2,4-dinitrophenol or 4-fluoro-3-nitroaniline which compete with FNPA for binding sites. The photo-probe is effective over a wide pH range (i.e. pH 2–11), and provides a sensitive tool for probing conformational and charge adjustments which increase or decrease the affinity of the binding site. Chymotrypsinogen was also sensitive to photolysis, indicating that FNPA binding sites are present in the zymogen structure. 相似文献
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