山核桃外果皮黄酮提取条件的研究

采用兮光光度法,以芦丁为对照品,乙醇回流萃取山核桃外果支中总黄酮．在革取过程中,通过单因素试验分析了乙醇浓度、苹取温度、萃取时间及料液比等4个主要因素对萃取率的影响．通过正交试验,得到最佳萃取工艺条件为：乙醇浓度为70％,萃取温度60℃,萃取时间为6h,料液比1：20．试验方法简便,结果可靠．     

正交设计法优选银线莲黄酮类化合物提取工艺研究

本实验采用正交设计法对银线莲黄酮类化合物提取工艺参数进行优化.以黄酮提取率为指标,以乙醇浓度、提取时间、料液比、提取温度、萃取液比为考察因素,采用正交试验优选最佳提取工艺.结果表明最佳提取工艺应为在80℃条件下提取,乙醇浓度90％,提取时间为2.0h,料液比1：20,萃取液用量为提取液的0.75倍,最后黄酮得率为1.697％.     

竹叶总黄酮提取工艺研究

探讨用醇提法提取竹叶中黄酮类成分的最佳工艺,为竹叶的开发利用提供理论依据。以竹叶为试材,以乙醇为溶剂,采用分光光度法对竹叶中的黄酮类化合物的含量进行测试。通过单因素实验研究乙醇浓度、料液比、提取温度、提取时间对总黄酮提取率的影响,再采用正交试验法优化提取总黄酮的最佳工艺条件。单因素实验和正交试验表明：影响黄酮提取率的因素主次顺序是：料液比〉乙醇浓度〉提取温度〉提取时间。最佳实验条件为料液比1：20,60%的乙醇,60℃提取4h,竹叶中黄酮的含量为7.88mg.g-1。     

正交法优化仙人掌中黄酮类物质提取条件的研究

采用正交法研究了乙醇溶剂提取仙人掌中黄酮类物质的工艺条件.利用单因素试验,确定影响黄酮提取效果的4个因素:乙醇浓度、提取温度、提取时间和料液比的较优水平,用正交设计试验优化提取工艺条件.结果表明,最佳提取条件为乙醇浓度(V/V)90%、料液比20/1、温度55℃、时间1 h.     

米糠总黄酮提取工艺的研究

米糠黄酮拥有多重生物活性,具有广阔的市场前景。研究了米糠黄酮提取工艺。试验采用溶剂加热回流法提取米糠中黄酮类化合物,采用单因素试验确定各因素对提取工艺的影响,正交试验确定最佳提取工艺。结果表明:对米糠中总黄酮的提取效果最大的因素是提取温度,其次是乙醇浓度,再是提取时间,影响最小的是料液比。总黄酮的提取工艺最佳参数为提取温度80℃,提取时间为3.5 h,提取溶剂为70%的乙醇,料液比为1∶40,米糠中总黄酮的提取率为1.515%。     

响应面法优化冻绿果实黄酮提取工艺

利用乙醇超声辅助提取技术,分别考察了液料比、乙醇浓度、提取温度和提取时间等因素对冻绿果实中黄酮提取量的影响,在此基础上,用响应面分析法优化了冻绿果实黄酮的最佳提取工艺参数为:液料比35(mL:g)、乙醇体积百分数65%、提取温度38℃、提取时间18 min。在此条件下,冻绿果实的黄酮提取量可达62.36 mg/g干重,与理论预测值基本吻合,说明该优化方案合理可行。     

正交优化橘皮黄酮的提取工艺研究

以橘皮为原料,探讨橘皮黄酮提取的最佳工艺条件。考察乙醇浓度、料液比、提取时间和提取温度等因素对橘皮黄酮得率的影响,在单因素试验的基础上,进行L9(34)正交试验。结果表明,最佳提取工艺条件为:乙醇浓度为65%,料液比为1:15,提取时间为40 min,提取温度为65℃,在此条件下,橘皮黄酮得率为8.94%。     

响应面法优化杨梅原花青素提取工艺

为优化杨梅原花青素的提取工艺参数,通过单因素实验,采用响应面法研究乙醇浓度、料液比、提取时间和温度等对杨梅原花青素提取的影响,以原花青素提取率为评价指标,通过Box-Behnken组合,建立杨梅提取的二次回归方程,得到最优提取条件.结果表明,杨梅原花青素提取得率的影响的顺序为:乙醇浓度温度时间料液比;杨梅原花青素的最佳提取工艺条件为:乙醇浓度为92%,提取温度75℃,提取时间57 min,液料比选取25:1(m L/g).该条件下,杨梅原花青素提取率的为30.03 mg/g.     

响应面法优化仙草黄酮提取工艺研究

采用响应面优化法对仙草中黄酮的提取工艺进行研究.将乙醇浓度、提取时间及液料比作为影响因子,在单因素试验的基础上,采用响应面Box-Behnken中心组合法,进行试验设计,将仙草中黄酮的提取率作为响应指标值,进行优化试验.试验结果说明各个因素对仙草中黄酮的提取率影响强弱次序为:乙醇体积分数液料比提取时间;仙草黄酮的最佳提取条件:乙醇体积分数60%,提取时间5 h,液料比30∶1(m L/g),该条件下得到的黄酮提取率最大,实际测定值为14.37%,与预测值(14.79%)没有显著性差异.表明响应面优化法分析的结果可信,所得的最佳提取条件为仙草中黄酮的综合利用奠定了基础.     

超声法提取橙皮黄酮的工艺研究

本文对橙皮中黄酮类化合物的超声提取工艺进行了研究。采取L9(34)正交试验,探讨了乙醇浓度、料液比、超声时间和提取温度对橙皮黄酮提取效果的影响。结果表明提取温度对提取效果的影响最为显著,最佳提取工艺条件为:乙醇浓度70%,提取温度70℃,超声时间30min,料液比1:30。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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