响应面分析法对酸提糯米藤多糖工艺的优化

目的:优化糯米藤多糖的回流提取工艺.方法:在单因素实验基础上,采用响应面分析法,以多糖提取率为响应值,通过回归分析各工艺参数与响应值之间的关系,由此预测最佳的提取工艺条件.结果:最佳工艺条件为:回流提取温度88.8℃,酸浓度0.322 mol/L,提取时间55.5 min,液固比22.1:1,其他条件为:浸泡时间30 min、提取次数2次,在最佳工艺条件下多糖提取率可达13.79 g/100 g.结论:响应面分析法优化稀盐酸回流提取多糖的预测准确、方便,所得的最佳提取工艺高效、可行.     

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.     

超声波及微波提取豆粕中总黄酮的工艺优化

对超声波及微波提取异黄酮的工艺进行优化.超声波提取最佳条件:60%乙醇、60℃、功率400W、提取30min,微波法提取最佳条件:微波功率560W,料液比为1:30g/mL,微波处理4min溶剂浸提40min.结果表明,超声波及微波处理能有效缩短提取时间,提高提取率.     

正交试验法优选坚龙胆中龙胆苦苷的提取工艺

目的:优选坚龙胆中龙胆苦苷的提取工艺.方法:以龙胆苦苷的含量为指标,采用高效液相色谱法进行含量测定,采用L9(34)正交设计试验,对提取次数、提取溶剂倍数和提取时间3因素进行考察,以确定最佳提取工艺.结果:提取3次,用10倍量的甲醇,提取时间每次20min为最佳提取工艺.结论:该工艺合理,且稳定可行.     

陈皮、白术挥发油的提取及其包合工艺的研究

确定陈皮、白术挥发油提取及其包合物制备最佳工艺.方法:水蒸气蒸馏提取挥发油和饱和水溶液法制备包合物,并用正交试验法,对挥发油提取与β-环糊精的包合进行3因素3水平考察.结果:最佳提取工艺A2B2C3,即陈皮、白术粉碎成过50目筛的粉末,加10倍水量,提取5h;最佳包合工艺A3B2C1,即用挥发油与β-CD投料比为1∶6,50℃搅拌包合5h,包合率为81.90%.结论:提取和包合工艺简单、易行、成本较低.     

甘草中甘草酸的多级逆流提取技术研究

研究利用多级逆流技术提取甘草酸的新方法.采用正交试验考察提取温度、提取时间、级数和液固比对提取效率的影响,确定多级逆流提取甘草酸的最佳工艺条件;在优选出的最佳工艺条件下,考察了提取溶剂对提取率的影响,并与室温冷浸法、超声波法、索氏提取法和微波提取法做了比较.结果表明:多级逆流提取甘草酸的最佳条件为提取温度70℃,单级提取时间60 min,液比6,提取级数为5.在此最佳条件下,多级逆流提取的提取率高于室温冷浸44.3 h、超声波提取40 min、索氏提取4 h、微波萃取54 min的提取率.多级逆流提取具有快速、高效、节能、节约溶剂的特点,用于中草药有效成分的提取,值得推广应用.     

搅拌回流法和微波法从花生壳中提取黄酮

以乙醇水溶液为提取剂,选择搅拌回流法和微波法利用正交实验从花生壳中提取黄酮,确定最佳实验条件,并且利用回收的乙醇和滤渣再进行提取实验.研究结果表明:搅拌回流法最佳实验条件是70%乙醇、提取温度70℃、提取时间4 h、料液比为1:40;微波法最佳实验条件是料液比为1:5、提取液pH值为5、提取时间为4min.提取液定性实验证明其中含有黄酮;旋转蒸发回收乙醇可以重复4次用于提取花生壳中的黄酮;新鲜乙醇可以重复3次用于提取滤渣中的黄酮.     

茶树花黄酮的提取及对羟自由基的清除效果

通过对茶树花物料粒度、不同提取剂和提取方式的比较,研究茶树花黄酮的最佳提取工艺;并比较不同提取方法获得的茶树花黄酮提取物对羟自由基(·OH)的清除效果.结果表明:乙醇热回流提取的最佳工艺条件为:体积分数95%的乙醇,料液比1∶15,80℃下批次提取90 min;超声波振荡提取最佳工艺为:体积分数95%的乙醇,料液比1∶30,提取温度45℃,批次提取80 min.超声波结合热提法获得的茶树花黄酮提取物对·OH的清除效果最好.     

玉米须蚕茧总皂苷提取工艺条件优化研究

目的 为充分利用玉米须蚕茧资源,研究提取玉米须蚕茧总皂苷的最佳工艺条件.方法 选用提取时间、提取次数、提取温度和加水倍数作为考查因素,采用纯物理的工艺流程从玉米须中提取总皂苷,通过正交试验,筛选玉米须蚕茧总皂苷的提取工艺条件.结果 玉米须蚕茧总皂苷提取最佳条件为乙醇浓度70%,料液比为1:20,60℃回流提取1.5 h.结论 可以通过正交试验优化提取玉米须总皂苷的最佳工艺条件.     

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.     

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