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71.
反相高效液相色谱法测定3种中成药中的葛根素 总被引:7,自引:0,他引:7
建立了测定小儿清感灵片、步长新脑心通胶囊和感冒清热颗粒 3种中成药中葛根素含量的反相高效液相色谱方法。采用APEXODS色谱柱 ,以醋酸铵缓冲液 (10 0mmol/L ,pH 5 0 ) 甲醇 (体积比为 75∶2 5 )的混合溶液为流动相 ,检测波长为 2 5 0nm ,流速为 0 8mL/min。葛根素在 2mg/L~ 2 0mg/L时其色谱峰面积与质量浓度的线性关系良好 (r =0 9999) ;上述 3种中成药中的葛根素含量分别为 3 48mg/g ,1 0 8mg/ g及 1 5 2mg/ g(蔗糖型 ) ;其加样回收率分别为 99 0 % ,93 4%和 97 5 %。该法简便、快速、专属性强 ,可以作为多种中药制剂中葛根素含量的测定方法。 相似文献
72.
以过硫酸铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,淀粉与丙烯酸/醋酸乙烯酯混合单体通过接枝共聚,制备了吸水及耐盐性能均较好的淀粉接枝丙烯酸/醋酸乙烯酯高吸水性树脂(CGAV)。最佳工艺条件为:淀粉10.0 g,m(混合单体)∶m(淀粉)=4∶1,w(引发剂)=0.3%,w(交联剂)=0.05%,于45℃反应2h~3 h。在最佳工艺条件下制得的CGAV吸去离子水率760 g.g-1,吸0.9%NaC l水溶液率68 g.g-1。 相似文献
73.
水稻腊质基因分子特性的研究 总被引:4,自引:0,他引:4
水稻腊质基因(Wx)负责胚乳与花粉粒中直链淀粉的合成。我们通过对限制图和DNA顺序有重叠的两个基因组克隆的分析,测定出了水稻Wx基因全长为5499bp的DNA顺序。比较水稻、玉米(Klsgen等)和大麦(Rohde等)中Wx基因的DNA顺序,弄清水稻Wx基因中存在13个内含子和14个外显子,通过微机对外显子顺序的翻译,得出了水稻Wx蛋白包括转运肽在内的609个氨基酸的排列顺序,并计算出它的分子量约为72kD。经比较,水稻Wx成熟蛋白的氨基酸顺序与玉米、大麦的没有明显地差异。但是,水稻Wx基因5′-上游区、3′-下游区和内含子区域的DNA顺序,以及Wx前体蛋白的转运肽区域的氨基酸顺序与玉米和大麦Wx基因的相应区域相比,它们之间的同源性却很低。 相似文献
74.
Yong Zhong DU Fu Qiang HU Hong YUAN Shinzo OMI 《中国化学快报》2006,17(4):553-556
Stable poly(styrene-co-sodium styrene sulfonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120 ℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization. 相似文献
75.
Shu Jun WANG Wen Yuan GAO Jing Lin YU Pei Gen XIAO 《中国化学快报》2006,17(9):1255-1258
Dioscoreae (Chinese name Shanyao), the rhizome of various species of genus Dioscorea opposita Thunb.(Dioscoreaceae), has been used as an important invigorant in traditional Chinese medicine (TCM) for many years1. Starch, the most abundant carbohydrate in … 相似文献
76.
CRYSTALLIZATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE FILLED WITH SiO2 NANOPARTICLES 总被引:3,自引:0,他引:3
Bao-qing Shentu Ji-peng Li Zhi-xue Weng 《高分子科学》2007,(3):227-233
Oleic acid (OA)-modified SiO2 (OA-m-SiO2) nanoparticles were prepared using surface modification method. Infrared spectroscopy (IR) was used to investigate the structure of the OA-m-SiO2 nanoparticles, and the result showed that OA attached onto the surface of SiO2 nanoparticles through esterification. Effect of OA concentration on the dispersion stability of OA-m-SiO2 in heptane was also studied, and the result indicated that OA-m-SiO2 nanoparticles were dispersed in heptane more stably than the unmodified ones. OA-m-SiO2 nanoparticles can also be dispersed in polypropylene (PP) matrix in nano-scale. The effect of OA-m-SiO2 on crystallization of PP was studied by means of DSC. It was found that the introduction of OA-m-SiO2 resulted in significant increase in the crystallization temperature, crystallization degree and crystallization rate of PP, and OA-m-SiO2 could effectively induce the formation of β-crystal PP. Effect of OA-m-SiO2 content on mechanical properties of PP/OA-m-SiO2 nanocomposites was also studied. The results show that OA-m-SiO2 can significantly improve the mechanical properties of PP. 相似文献
77.
The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu^+ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis. 相似文献
78.
Ce4+-Ce3+循环体系引发淀粉与丙烯酰胺接枝共聚合反应动力学研究 总被引:16,自引:1,他引:16
The cyclic initiating system of Ce4+ - Ce3+ - Ce4+, in which the product of reduced ion Ce3+ forming from Ce4+ after initation being oxidized again to the original oxidizing ion Ce4+ is examined. The characters of process of the graft copolymerisation using the cyclic initiating system is compared with the ones using ceric and persulphate individually. When using the cyclic systerm as initator, it was more effective to graft polymerise acylamide onto starch and a rather high proportion of graft copolymer was made as opposed to using persulphate individually. 相似文献
79.
以乙酰丙酮镍、油酸、油胺为原料,十八烯为溶剂,聚乙烯吡咯烷酮为表面活性剂,采用溶剂热法,在不同反应条件制备了纳米级氧化镍材料.通过X射线衍射(X-ray diffraction,XRD)、透射电子显微镜(Transmission electron microscope,TEM)、紫外-可见光吸收光谱(Ultraviolet-visible spectroscopy,UV-Vis)光谱分析以及塔菲尔(Tafel)测试考察了反应物比例、保温时间、表面活性剂(PVP)、油胺的量对产物微结构、粒径、形貌、光学以及电化学活性性能的影响.实验结果表明:在反应物n[Ni(acac)2]∶n(OA)=1∶2、添加剂PVP质量分数为1.66%、油胺物质的量为30 mmol、200℃下保温8 h时,可获得粒径约为30~40 nm纯相氧化镍,具有最佳电化学活性,交换电流密度为J0=1.23×10-2 mA·cm-2. 相似文献
80.