茶多酚的加速溶剂萃取与分析

以毛尖茶叶为原料,用加速溶剂萃取法提取茶多酚粗品用单因素试验研究和正交试验考察乙醇体积分数、温度和循环次数对萃取率的影响。用二极管阵列高效液相色谱(DAD-HPLC)对照测定加速溶剂萃取的茶多酚粗品、微波辅助提取的茶多酚粗品和商品茶多酚。结果表明:茶多酚粗品的制备最佳条件为萃取温度160℃、乙醇体积分数60%、循环萃取2次。高温加速溶剂萃取法对茶多酚的粗提率较高,但其中儿茶素的总量却显著下降降低提取温度,则茶多酚中的主要功能成分儿茶素的含量显著高于微波辅助提取法。     

硅胶柱层析法提纯茶多酚的研究

采用硅胶柱层析法分离精制茶多酚.以粗茶多酚为原料,采用硅胶为吸附剂,乙酸乙酯为洗脱剂,得到的茶多酚儿茶素总含量可达到90%以上,其中酯型儿茶素含量超过75%,EGCG最高接近60%,咖啡因含量可降低至不能检出.该方法操作简便,分离效果好,使用成本低.     

离子抑制色谱法测定甘草酸

本文研究了离子抑制色谱测定甘草及甘草酸（ＧｌｙｅｙｒｒｈｉｉｃａｃｉｄＧＡ）粗品中ＧＡ含量的方法，选择色谱分离条件，讨论流动相组成对分离的影响，实验表明：该方法简便、快速。准确，可用于ＧＡ的快速测定。     

贮藏时间对武夷岩茶金锁匙生化成分及感官品质的影响

以轻火、中火武夷岩茶金锁匙为实验材料,研究不同贮藏时间对其生化成分及感官品质的影响,为武夷岩茶的科学品饮、储藏、运输、营养保持等提供理论参考。结果表明:贮藏过程中轻火、中火金锁匙茶多酚、儿茶素、咖啡碱、水浸出物含量(生化成分与干物质质量比)均呈下降趋势,水分含量呈上升趋势,氨基酸含量呈先增加后减少的趋势。贮藏12个月轻火、中火金锁匙茶多酚、儿茶素、酯型儿茶素、非酯型儿茶素、咖啡碱含量分别降低21.03%、19.48%;21.87%、17.24%;30.58%、26.76%;10.25%、6.45%;17.60%、13.36%。轻火金锁匙贮藏6个月氨基酸含量最高,达2.32%;中火金锁匙贮藏8个月氨基酸含量最高,达2.25%。贮藏前期,轻火、中火金锁匙火气逐渐退去,感官品质得到提升;贮藏后期,其滋味变得更加甘醇,但香气鲜锐度略有下降,因此感官品质得分先增加后略有降低。轻火金锁匙贮藏6个月感官品质得分最高,中火金锁匙贮藏8个月感官品质得分最高。研究结果表明,合理贮藏有利于提高武夷岩茶的感官品质。     

薄层色谱法鉴别东方草莓药材中儿茶素

参照《中国药典(一部)》(2010版)对薄层色谱鉴别法的规定,以东方草莓药材中的一特征性成分(+)-儿茶素为对照品,分别采用薄层色谱法对7个产地的10批东方草莓药材进行检测,建立了东方草莓药材的薄层色谱鉴别方法.该方法操作简便、准确、可靠.     

西南鬼灯檠的化学成分研究

目的：对西南鬼灯檠化学成分进行初步研究。方法：采用溶剂法提取西南鬼灯檠的化学成分,常规硅胶柱层析、凝胶过滤层析和薄层色谱分离纯化,根据化合物的物理、化学性质和波谱解析鉴定了4个化合物。结果：4个化合物分别被鉴定为儿茶素（catechin,Ⅰ）、儿茶素-3—O-没食子酸酯（epicatechin-3—O-gallate,Ⅱ）、岩白菜素（bergenin,Ⅲ）和齐墩果酸（oleanoli cacid,Ⅳ）。结论：这4个化合物均是首次从西南鬼灯檠中分离得到。     

茶多酚及茶多酚锗的组成、结构和抑制肺癌细胞生长速率的研究

采用有机合成法合成茶多酚-锗化合物.运用反相液相色谱技术初步分离茶多酚和茶多酚锗的酚类组成.选用基质辅助激光解吸电离化飞行时间(MALDI-TOF)质谱技术分析茶多酚及茶多酚-锗的组成和结构.结果表明,茶多酚主要由儿茶素及酚类化合物组成,其中(-)表没食子儿茶素没食子酸酯(EGCG)、(-)表没食子儿茶素没食子棓酸甲酯(EGC-MG)和表三羟基黄烷-3-醇没食子酸酯(EZG)易与Ge4 反应且形成含锗的酚类化合物.茶多酚及茶多酚-锗化合物均有抑制肺癌细胞生长的能力,其抑制速率随着酚类化合物浓度增加而提高,但茶多酚锗抑制速率高于茶多酚近1倍.     

双长链酯胺的合成工艺条件对产物组成的影响

在三乙醇胺脂肪酸酯型双长链酯基季铵盐的合成中，单／双／三长链的比例对其性能具有重要的影响．采用高效液相色谱，对三乙醇胺双硬脂酸酯的酯化工艺条件(反应温度、反应时间、反应物配比、催化剂及其用量等)与酯化产物中单、双、三酯含量之间的关系进行了研究．发现较高的反应温度可使单酯含量降低，双酯、三酯含量升高；合适的催化剂和反应时间有利于双酯含量的提高．在较高的反应温度(170℃)下，综合选择合适的反应物的物质的量比、反应时问和催化剂，可获得双酯含量迭61％的产物．     

黔产茶叶中儿茶素类成分的HPLC分析研究

建立一种同时测定黔产茶叶中四种儿茶素(表没食子儿茶素没食子酸酯、表儿茶素、没食子儿茶素没食子酸酯和表没食子儿茶素)含量的高效液相色谱分析方法.采用Agilent 1100高效液相色谱仪、Welch色谱柱ultimate XB-C18(4.6 mm×250 mm,5μm),以甲醇-0.1%磷酸为流动相进行梯度洗脱,在流速1 m Lmin-1、柱温35℃、检测波长278 nm的条件下测定了该四种儿茶素的含量,回收率均在98.4%~102.00%之间,各组分回归方程的相关系数均在0.99996以上.该方法选择性好,灵敏度高,重复性好,检测快速准确,适合用于茶叶中儿茶素含量的测定.     

茶多酚对自由基抑制效应

采用循环伏安法测定自制茶多酚及标准儿茶素的氧化峰电位．结果表明,前者高于后者,即后者还原能力较强．经加温强化处理的各种食用油,分别加入同量、不同量的上述两种试样;不同来源的食用油加同量的标准儿茶素,用ＥＳＲ方法测试它们随温度、时间条件的改变引起自由基强度变化的规律．结果说明：茶多酚、儿茶素均有很强的自由基抑制效应,儿茶素更强（和还原能力较强相一致）．该研究对于从茶叶中提取茶多酚并用于食品工业,具有一定的理论意义和应用的参考价值．     

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.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of