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1.
超临界CO2萃取两头尖皂甙研究   总被引:2,自引:0,他引:2  
应用超临界CO2萃取两头尖皂甙,采用正交设计优化条件,以齐墩果酸为对照品,用香草醛—高氯酸显色法测定皂甙含量,来研究两头尖皂甙的超临界CO2提取方法.实验得出超临界萃取的最佳条件为:萃取压力30MPa,萃取温度50℃,萃取时间1.5h,夹带剂95%乙醇用量为20%.结果证明超临界CO2萃取两头尖皂甙方法是可行的,为提高皂甙提取率,预处理工艺有待进一步实验研究.  相似文献   

2.
苦瓜皂甙的提取过程研究   总被引:20,自引:0,他引:20  
研究了苦瓜皂甙的提取工艺和测定方法.以苦瓜皂甙中主要成分Mordicoside A为对照,采用分光光度法对苦瓜中皂甙成分进行定量分析;以提取温度、浸泡时间、乙醇的质量分数和料液比为考察因素,采用单因素试验及正交试验对苦瓜中皂甙进行了提取务件优化的试验.试验结果表明:浸提温度60℃,浸提时间6h,乙醇质量分数为70%及料液比1:5为最佳提取条件.苦瓜皂甙粗品的提取率为苦瓜干粉的0.052%,其中皂甙的质量分数为43.333%.  相似文献   

3.
薯蓣皂甙元是合成甾体激素药物和甾体避孕药物的重要原料,是黄姜中的主要活性物质。采用正交实验的方法,探讨了经过二次酸水解法从黄姜中提取薯蓣皂甙元的工艺条件,结果表明该方法提取的薯蓣皂甙元产率达到了2.41%,比直接水解法(2.20%)提高了9.55%。另外,采用熔点、元素分析法、红外、核磁等一系列的手段对产品进行表征,结果表明该法是可行的,提取的薯蓣皂甙元的质量纯度达到了工业的要求。  相似文献   

4.
以取代苯胺为起始原料,与水舍氯醛及盐酸羟胺反应生成取代的异亚硝基乙酰苯胺(2a-2e),在浓硫酸作用下环合,经水解后以65.9%-80.3%的总收率得到5位取代的靛红(3a-3d),以39.5%的总收率得到7位取代靛红(3e)。化合物2a-2e的合成作为Sandmeyer法合成取代靛红的关键步骤,对其制备工艺进行优化并确定了最佳反应条件:反应温度为85℃,反应时间为1.5~2.5h。  相似文献   

5.
以丙烯酰胺和二丙酮醇为原料,以浓硫酸为催化剂,合成了N-(1,1-二甲基-3-氧代丁基)-2-丙烯酰胺。采用红外光谱、核磁共振、熔点测定等方法对产物进行了表征。得到最佳反应条件为n(丙烯酰胺):n(二丙酮醇):n(浓硫酸)=2:4:1,反应温度为60℃,反应时间为6h。得到产物的产率为20.0%,熔点为51~53℃。  相似文献   

6.
目的:建立蒙药查干汤中苦参碱的含量测定方法.方法:采用了薄层扫描法,以苯-丙酮-醋酸乙酯-浓氮试液(2:3:4:0.2)为展开剂,稀碘化铋钾试液为显色剂;λS=520nm,λR=650nm,双波长反射法锯齿扫描.结果:苦参碱溶液在2.14~6.42μg范围内具有良好的线性关系,r=0.998;平均回收率为97.62%.CV(%)=1.73(n=5).结论:建立的方法分离效果好,结果稳定、可靠、准确,具有良好的重复性,可作为该制剂中苦参碱的含量测定方法.  相似文献   

7.
二溴代烷制备的探讨   总被引:2,自引:0,他引:2  
以二溴代烷制备为例,探讨了浓硫酸在二溴代烷制备过程的催化作用及研究脂肪族二元醇与环氧化合物转化为二溴代烷的难易.结果表明:浓硫酸的用量对环氧化合物以及脂肪二元醇合成二溴代烷的收率有很大的影响.  相似文献   

8.
利用混合溶剂法,直接用对羟基苯甲醛与吡咯反应合成了meso-5.10,15,20-四(对羟基苯基)卟啉,探讨了混合溶剂的配比、反应温度、反应时间等条件对反应的影响,其最佳工艺条件为:混合溶剂配比(V/V)丙酸:乙酸:硝基苯=2:2:1;在130~140℃,反应时间60min;产率达到39.68%.利用室温固相合成法合成了标题卟啉化合物与Fe2^ ,Fe^3 ,Co^2 ,Ni^2 ,Mn^2 ,Cu^2 等金属离子形成的配合物,产率为87.02%~89.64%.利用元素分析,UV-Vis.IR,^1HNMR,对卟啉化合物及其配合物进行了表征,利用TG—DTA研究了它们的热稳定性.利用ESR研究了它们的顺磁性.  相似文献   

9.
目的:测定匝迪-5中胡椒碱的含量.方法:采用HPLC法.结果:进样在0.24~1.2μg有良好的线性关系,r=0.9998。平均回收率为98.1%,CV=1.92%(n=5).结论:该方法分离效果好,简便、快速,结果准确,使用于测定匝迪-5中胡椒碱的含量.  相似文献   

10.
目的:观察物理治疗联合灯盏细辛及七叶皂甙治疗神经根型颈椎病患者的疗效。方法:将82例神经根型颈椎病患者随机分为观察组和对照组,每组41例。观察组:物理治疗后静脉滴注灯盏细辛和七叶皂甙注射液;对照组:静脉滴注灯盏细辛和七叶皂甙注射液。对2组结果进行比较分析。结果:观察组治愈率36.6%,显效率56.1%。对照组治愈率26.8%,显效率43.9%,两组疗效比较,差异有统计学意义(P〈0.05),观察组疗效明显优于对照组。结论:物理方法联合灯盏细辛及七叶皂甙治疗可明显改善神经根型颈椎病患者的临床症状,提高疗效。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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