索氏法提取香樟精油的研究

本文研究了以香樟叶为原料,利用索式提取方法研究香樟精油提取工艺。探讨了溶剂种类、提取温度、提取时间、料液比对香樟叶中精油提取效果的影响,并通过正交试验确定其最佳提取工艺。结果表明:无水乙醇为最佳提取溶剂,最佳提取条件为:料液比8∶1,提取温度70℃,提取时间90 min。在此条件下,香樟叶的出油率达3.661%。     

超声波和微波辅助法提取茵陈总黄酮的条件研究

以70%乙醇为提取溶剂,分别用超声波和微波辅助法提取茵陈黄酮类化合物,以总黄酮提取率为考察指标,通过正交实验设计优选最佳工艺条件.结果表明:超声波辅助提取的最佳条件为提取时间60min、温度60℃、5g原料使用溶剂125mL、超声波功率200W;微波辅助提取的最佳条件为提取时间24 min、5g原料使用溶剂125mL、微波功率350W.最佳提取条件下,超声波辅助提取率(3.29%)略高于微波辅助提取率(3.09%),微波辅助提取法能明显节省提取时间.     

响应面优化超声辅助提取虎眼万年青多糖工艺

采用响应面法优化虎眼万年青多糖的超声提取工艺。在单因素试验的基础上,采用Box-Benhnken试验设计优化超声时间(X1:20~40min)、提取温度(X2:50~70℃)、超声功率(X3:900~1200W)和溶剂原料比(X4:30~50mL·g-1)对虎眼万年青多糖提取得率(Y)的影响。虎眼万年青多糖超声提取的最佳工艺条件为:超声时间30.05min、超声温度59.47℃、超声功率1050.15W、溶剂原料比40.11mL·g-1。在最佳的提取条件下,虎眼万年青粗多糖实验得率为50.2%,与模型预测值接近。应用响应面分析法优化得到的超声辅助提取参数准确、可靠。     

脱脂葡萄籽中原花青素提取工艺研究

采用溶剂回流提取方法,以脱脂葡萄籽为原料,以原花青素提取率为考察指标,研究了提取溶剂种类、溶剂浓度、提取温度、料液比、提取时间、提取次数等因素对葡萄籽中原花青素提取效果的影响;通过正交试验设计,确定脱籽葡萄籽中原花青素的最佳提取工艺条件为:提取溶剂70%乙醇,提取温度50℃,料液比1∶7,提取时间50 m in,提取3次;在此优化条件下脱脂葡萄籽中原花青素的平均提取率为5.00%。     

九连环中生物碱的提取工艺研究

在生物碱的研究现状和提取工艺基础上,以产自陕西省周至县的九连环全草为原料,通过单因素试验和正交试验,得出了其生物碱的最佳提取分离条件:乙醇为提取溶剂,提取时间60min,提取次数2次,料液比1:7,萃取溶剂氯仿,萃取pH10,萃取次数3次。利用该提取工艺参数提取总生物碱,用分光光度法对提取产物进行含量测定,总生物碱的提取率为6.8%。     

从鱼腥草中提取鱼腥草素分离工艺研究

利用溶剂提取法从鱼腥草中提取鱼腥草素．研究了乙醇浓度、固液比、提取时间、提取温度等工艺条件对鱼腥草素提取率的影响,最佳提取工艺条件为:以50%乙醇溶液为溶剂,固液比1:30,温度50℃,时间65min,提取率可达11．0%．     

以乙醇、乙醇/水为溶剂提取白桦树皮中桦木醇的工艺研究

分别以乙醇、乙醇/水、水为提取剂,研究从白桦树皮中提取桦木醇的工艺,确定了用乙醇作提取剂的最佳提取工艺条件:固液比(g∶mL)为0.083,抽提时间6,h;分别用异丙醇和乙醇作溶剂,通过两步重结晶操作,纯化桦木醇,得到桦木醇产品的产率达19.8%,熔点257.7～258.9,℃,纯度98%.     

赶黄草总黄酮类化合物的提取纯化工艺研究

以赶黄草为原料,选择单因素和正交试验筛选了赶黄草回流提取和超声提取总黄酮的最佳工艺条件,并对提取出的总黄酮利用聚酰胺树脂进行纯化,筛选出纯化最佳条件.结果显示最佳回流提取条件为:料液比1:15、提取温度60℃、乙醇体积分数60％、提取时间1 h.超声最佳提取条件分别为料液比1:25,提取温度50℃,乙醇体积分数60％,提取时间50 min.聚酰胺树脂的纯化最优条件为:选择60～80目聚酰胺树脂、溶液pH值为4、装柱比例1:15、拌样比例1:3、洗脱溶剂pH值为8、乙醇体积分数为70％,并且乙醇用量需大于3倍量保留体积.通过实验对比和筛选赶黄草黄酮的提取工艺条件和树脂最佳纯化条件,为赶黄草黄酮未来的提取纯化类实验研究提供实验数据参考.     

从新鲜番茄中提取番茄红素工艺的研究

研究从新鲜番茄中提取番茄红素粗产品,并进一步分离纯化的工艺条件。探索提取溶剂、物料比、提取温度、浸取时间、搅拌条件、冷冻处理对番茄红素提取量的影响,确定以番茄为原料的最佳提取工艺条件,将提取液减压浓缩并结晶纯化番茄红素。     

迎春花黄色素的提取工艺研究

研究了从迎春花中提取天然黄色素的方法．结果表明：该黄色素不溶于水，在无水乙醇、异丙醇、丙酮、氯仿、甲苯、石油醚等有机溶剂中以丙酮为最佳溶剂，丙酮提取液的λmax为415nm．色素提取的较优工艺条件是，1g干花粉加入40ml pH6的丙酮溶液。60℃恒温浸提1h．     

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     

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     

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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