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1.
研究还阳参的化学成分。采用无水乙醇浸泡提取制得浸膏,再将浸膏加水混悬后依次用石油醚、乙酸乙酯和正丁醇萃取,制得各层提取物。用柱层析、高效液相色谱等分离方法进行分离,得到5种单体化合物,经^1HNMR、^13CNMR确定单体化合物为叶绿素、蒲公英甾醇乙酸酯、葡萄糖、伪蒲公英甾醇乙酸酯、萨谷甾醇葡萄糖苷。  相似文献   

2.
东北苍耳子化学成分研究   总被引:5,自引:0,他引:5  
本文采用无水乙醇浸泡提取制得浸膏,再将浸膏加水混悬后依次用石油醚、乙酸乙酯和正丁醇萃取,制得各种提取物。用柱层析、高效液相色谱等进行分离,得到两种单体化合物,经1HNMR鉴定并与文献对照,确定一种为xanthinosin,另一种为β—谷甾醇。  相似文献   

3.
东北苍耳茎叶化学成分研究   总被引:1,自引:0,他引:1  
本文采用乙醇浸泡提取制得浸膏,再将浸膏加水混悬后依次用石油醚、乙酸乙酯和正丁醇萃取,制得各种提取物。用柱层析、高效液相色谱等进行分离,得到两种单体化合物,经1HNMR鉴定并与文献对照,确定一种为苍耳亭,另一种为β-谷甾醇葡萄糖苷。  相似文献   

4.
研究了嘉祥白菊花中黄酮类化合物的提取分离和结构鉴定.采用超声波提取法进行提取总黄酮,制得黄酮浸膏.样品经大孔树脂柱、硅胶柱分离,然后用TLC进行鉴定合并.最后经过减压蒸馏、冷冻干燥和多次重结晶后制得一种纯品,并通过红外和核磁等手段,对该纯品进行表征.  相似文献   

5.
采用甲醇浸泡提取制得浸膏,再将浸膏加饱和食盐水溶解后依次用正己烷萃取除去油脂,再用二氯甲烷萃取浓缩萃取物。用柱层析、重结晶和高效液相色谱等进行分离,得到两种单体化合物,经1H-NMR,13C-NMR和IR鉴定并与文献对照,确定一种为紫杉吉酚,另一种为紫杉平F。  相似文献   

6.
在超声辅助条件下,提取"对叶大戟"中的化学成分,经减压浓缩后得到浸膏,利用大孔树脂色谱法、凝胶色谱法对萃取物进行梯度洗脱,最后用1 H NMR、13 C NMR、ESI-MS对所得的产物进行结构鉴定.结果表明从"对叶大戟"萃取物中提取出了一种黄酮类化合物:山奈酚-3-O-β-D葡萄糖醛酸苷.  相似文献   

7.
苍耳子提取物的GC/MS分析   总被引:2,自引:0,他引:2  
本文采用乙醇浸泡提取制得浸膏,再将浸膏加水混悬后依次用石油醚、乙酸乙酯和正丁醇萃取,制得各种提取物。其中石油醚层提取物占总量的50%以上,采用GC/MS对石油醚层进行分析,其主要成分为:亚麻酸乙酯,硬脂酸,正十九烷,亚麻酸甲酯,棕榈酸。  相似文献   

8.
日本苦苣菜Sonchus oleraceus L.的化学成分研究   总被引:1,自引:0,他引:1  
将新采摘的日本苦苣菜(Sonchus oleraceus L.)粉碎后用甲醇浸泡,浸出液依次用正已烷、乙酸乙酯和氯仿萃取,制得相应的提取物。乙酸乙酯提取物被进一步采用柱层析及高效液相色谱分离,得到三种化合物。利用红外光谱、^1H—NMR、^13C-NMR方法对得到的化合物进行结构表征,证实其分别为β-谷甾醇、脱镁叶绿酸甲酯(Phaeophorbide—a methyl ester),和10-羟基脱镁叶绿酸甲酯Methyl(10s)-hydroxypheophorbide;其含量分别占乙酸乙酯提取物的0.0234%,0.115%和0.030%。  相似文献   

9.
通过芳醛与丙酮的羟醛缩合,经过还原,Vilsmeier-Haack反应,氧化四步反应制得脱落酸类似物,然后与α-氨基酸酯进行缩合反应,合成了6个未见报道的目标化合物,利用^1H NMR,IR,MS和元素分析表征了化合物结构,^1H NMR证实,目标分子中的2位和4位碳碳双键为反式构型。初步的生物活性测定表明,部分化合物具有一定的程度的植物生长抑制活性,如化合物Ⅶc,Ⅶc和Ⅶf在10mg/L浓度下对黄瓜子叶生根抑制率均为100%。  相似文献   

10.
以2-(4-硝基苯基)乙酸为主要原料,经酰氯化、N-酰化、还原、N-烷基化、氢化还原、甲磺酰化制得抗心率失常新药多非利特,总收率为17.4%。所得化合物的结构由元素分析、^1H—NMR、IR和MS确证。  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.
<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   

19.
20.
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has  相似文献   

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