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101.
将凝胶渗透色谱(GPC)中的示差与紫外检测器联用,测定了无规共聚丁苯橡胶和SBS三元嵌段共聚物中各级分的组成变化.实验方法选择中对比了两种浓度参数的确定方法,发现通过改变注射量来实现浓度变化的方法优于使用系列浓度样品的方法.分别测定标准样品在紫外和示差检测器上信号产生的时间间隔可以确定两个检测器上信号的时间差.根据紫外-示差检测器联用可以看到SBR无规共聚物和三嵌段SBS共聚物样品中每一个级分中随着相对分子质量的变化,苯乙烯含量的变化. 相似文献
102.
A ligand,(N,N′-dibenzylethane-1,2-diamine)(L),and its complex with copper acetate was synthesized and characterized by some spectral analyses.The copper ! ion is six-coordinated and exhibites octahedral coordination geometry,the coordination atoms are four nitrogen atoms from two(L) ligands and two carboxyl oxygen atoms from two acetic acid groups,respectively.After studying the interaction of the complex with calf thymus DNA through UV and fluorescence spectra,we can find that there is a strong binding and a large affinity berween the complex and calf thymus DNA.CCDC: 649416. 相似文献
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104.
The rheological properties of titanium dioxide dispersed in water are measured over a wide range of powder concentrations, temperatures, and pH values. The value of intrinsic viscosity of titanium dioxide measured with an Ubbelohde capillary viscometer is 3.55, which is useful for determining the shape and aggregation property of the particles. The yield stress and steady shear viscosity of titanium dioxide with broad and narrow particle size distributions were measured over a wide range of solid volume fractions on a Brabender rheometer. It is observed that the rheological properties of the suspensions are quite different due to the difference in particle size distributions. Quemada, Casson, and Zhou's models were used to fit the experimental data and useful parameters were obtained. Calculated data are also in good agreement with the experimental data. As expected, the shear viscosity and yield stress decrease with increasing temperature. But when the temperature is around 50 degrees C, yield stress increases with increasing temperature while shear viscosity exhibits a complex behavior. The phenomena are very interesting and special. The Peclet number was used to analyze the shear thickening behavior. Models were also used to describe the shear viscosity under different temperatures and the master plots of the reduced variables eta/eta(infinity) vs t(c)gamma; at different temperatures are superimposed, which means the agreement is fair and the models are suitable to describe the rheological properties of titanium dioxide suspensions. pH effects were investigated on a Rheometrics RFS-II rheometer and it was found that pH can change the surface charge of the particles, which also affects the rheological behavior. The pH at which maximum shear viscosity and yield stress occur is in concordance with the isoelectric point. Copyright 2001 Academic Press. 相似文献
105.
106.
采用热化学气相沉积(TCVD)法裂解酞菁铁(FePc)和乙烯(C2H4)制备出高210 μm的取向碳纳米管阵列(ACNTA). 用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、拉曼光谱和X射线光电子能谱(XPS)对制备的样品进行了表征, 系统研究了反应温度、反应时间、C2H4流量对ACNTA生长的影响. 结果表明, 样品具有高取向性且纯度高. 800 ℃是裂解FePc和C2H4制备ACNTA的最优温度, 催化剂的活性可以保持较长时间(60 min), 通入C2H4促进了ACNTA的快速生长, 最适合流量为50 cm3/min. 相似文献
107.
聚碱性品红修饰电极的制备及应用 总被引:31,自引:0,他引:31
研究了碱性品红在玻碳电极上聚合的最佳实验条件及其聚合机理,发现该修饰电极的多巴胺具有良好的催化作用,能大大提高多巴胺在的玻碳电极上的响应,在pH=7.0的磷酸盐缓冲溶液中,用修饰电极测定巴胺的线性范围为2×10^-7~1×10^-5mol/L,检测限为1×10^-7mol/L,并且具有稳定性好,响应快,选择性等特点。 相似文献
108.
109.
YuYingFENG XiaoTianGU JiaHongZHOU JianChunBAO GangLI TianHongLU 《中国化学快报》2004,15(12):1505-1508
New Ge/SiO2 glasses have been synthesized by heating the GeO2/SiO2 dry gels under H2 gas at 700℃. The resulting fluorescence spectra show that this kind of Ge/SiO2 glasses emit strong photoluminescence at 392 nm (3.12 eV), medium strong photoluminescence at 600 nm (2.05 eV) and weak photoluminescence at 770 nm (1.60 eV) respectively. Possible photoluminescence mechanisms are also discussed based on the results of X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS). 相似文献
110.
GU Jin-ying HU Xiao-jun SHI Xian-fa LI Yan-jun QI Yong-lu JI Liang-nian 《高等学校化学研究》2007,23(2):241-244
Introduction Calixarenes are versatile host molecules for molecular recognition and supram olecular assembly be-cause its functional groups can be readily introduced in-to the phenolic OH or the para position to realize a wide variety of functions[1-5]. 相似文献