不同预处理方式对木立芦荟总黄酮含量的影响

不同预处理条件下（将样品浸泡24h和不浸泡）超声波提取木立芦荟叶、茎中总黄酮,并用分光光度法测其含量．结果表明：木立芦荟茎浸泡24h超声提取总黄酮的含量略高于不浸泡直接超声提取的总黄酮含量,但木立芦荟叶不浸泡直接超声提取的总黄酮含量高于浸泡24h超声提取的总黄酮含量,木立芦荟叶里的总黄酮含量都高于茎中的总黄酮含量．     

鱼腥草总黄酮的提取及其方法对比

采用水提法、有机溶剂提取法、索式抽提法、超声波法等4种方法分别提取鱼腥草不同部位（根、茎、叶及全草）的黄酮,结果表明：索式提取法为鱼腥草总黄酮的最佳提取方法,鱼腥草不同部位的总黄酮含量由高到低依次为叶、全草、茎、根.     

蒙药材多叶棘豆中总黄酮的提取及含量测定

本实验采用超声波乙醇浸提法从多叶棘豆中提取总黄酮,并用分光光度法测定其含量．实验结果表明,用80％的乙醇浸泡24h,超声50min,可得到较多含量的黄酮,且测得总黄酮含量为2．506mg／g,回收率为99．696．     

库拉索芦荟和木立芦荟叶的形态结构及有效成分含量的比较

应用植物解剖学和植物化学相结合的方法比较研究了3年生库拉索芦荟(Aloe vera L.)和木立芦荟(Aloe arborescens Mill)的形态结构和芦荟素、芦荟多糖等有效成分的含量.研究结果表明:(1)库拉索芦荟茎极短,叶丛生,成熟叶片长60~80 cm,质量400~550 g;木立芦荟茎高50~70 cm,叶互生,成熟叶片长40~50 cm,质量100~150 g.(2)两种芦荟叶都由表皮、同化组织、贮水组织和维管束组成.库拉索芦荟叶的贮水组织占横切面的90%以上,而木立芦荟叶的贮水组织仅占横切面的70%.(3)库拉索芦荟叶中芦荟素含量为1.46%,芦荟多糖含量为3.56%,宜作为芦荟多糖的原料;木立芦荟叶中芦荟素含量为2.15%,芦荟多糖含量为2.58%,宜作为芦荟素等蒽醌类物质的原料.研究结果为芦荟的引种栽培、采收和产品加工提供了科学依据.     

剑叶金鸡菊植株不同器官总黄酮和总皂甙含量的测定

采用冷浸提取、超声波提取及索氏提取法研究了剑叶金鸡菊(Coreopsis lanceolata)不同器官总黄酮和总皂甙的含量.结果 表明,剑叶金鸡菊花总黄酮和总皂甙含量显著高于根、茎和叶的含量.超声波提取方法操作简便、快速,提取效率高,在粗提中显示明显的优势,利用该方法提取剑叶金鸡菊花总黄酮含量可达24.33 mg/g...     

银杏花粉总黄酮提取工艺优化

用正交实验和单因素实验考察了索氏提取不同有机溶剂萃取法、不同条件乙醇回流提取法和超声提取法对银杏花粉总黄酮含量的影响,结果表明:正丁醇萃取法总黄酮含量明显高于乙酸乙酯萃取法;回流提取,以12倍量75%乙醇回流提取1.5 h,2次为最佳条件;超声提取用60%乙醇3、0 min为宜.     

沙棘果渣中总黄酮提取的研究

研究了从沙棘果渣中提取黄酮的工艺,考察了提取溶剂和果渣脱脂与否对提取效果的影响,在此基础上采用正交实验方法确定了沙棘果渣总黄酮的常规提取最佳条件：石油醚脱脂,质量分数为65%的乙醇溶液作为提取剂,提取温度为80 ℃,提取1 g果渣的每次溶剂用量为8 mL,提取次数为3次(每次为1h),在常规提取的最佳条件下沙棘果渣的总黄酮得率高达0.534 4%。尝试了超声辅助提取,结果表明提取前用超声预处理15 min,可以大大减少溶剂用量和提取时间,而黄酮得率保持不变。     

小鱼仙草总黄酮提取工艺的初步研究

利用聚酰胺-硝酸铝显色法测定不同产地小鱼仙草(茎、叶)总黄酮含量。对不同酒精体积分数、提取倍量、提取温度及提取时间等条件进行了初步分析。结果表明，40倍量、75％乙醇于80℃恒温中提取3h为最佳条件。在此条件下，1号小鱼仙草总黄酮含量为8．67％，2号小鱼仙草总黄酮含量为12．46％，3号小鱼仙草总黄酮含量为3．16％。     

热水浸提法提取库拉索芦荟花多糖的研究

采用热水浸提法提取库拉索芦荟花多糖,对温度、时间、加水量、芦荟花粒度4个工艺条件进行了研究.本实验条件下,芦荟花多糖提取的最佳条件为:温度:100℃;粒度:40-60目;时间:4 h;加水量:100 mL.分两次提取比单次提取多糖收率可提高10%.     

浸泡预处理提取伊朗蒿精油及其对毕赤酵母的抑制作用研究

目的:研究浸泡预处理提取伊朗蒿精油的最佳条件及精油的抑菌效果.方法:采用浸泡预处理,并试用不同的条件对精油进行提取,同时采用滤纸片扩散法来检测精油对于毕赤酵母生长的抑制作用.结果:浸泡预处理提取伊朗蒿精油的最佳工艺是料液比为1∶15;浸泡预处理24h后回流5h,得到的精油量为12.0ml/kg.结论:伊朗蒿精油对于毕赤酵母的生长具有明显的抑制作用.     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<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