南沙参多糖分离工艺优化研究

利用乙醇沉淀法设计采用三因素三水平正交实验,对南沙参多糖最佳分离工艺进行了优化研究.正交实验结果表明:乙醇沉淀法中三因素对南沙参多糖分离的影响顺序为:沉淀时间＞乙醇体积分数＞乙醇加入量,最佳分离工艺为:乙醇体积分数80%,沉淀时间8h,乙醇加入量3倍体积.     

刺五加总黄酮提取工艺优化研究

采用均匀设计四因素三水平正交实验方法,对刺五加总黄酮最佳提取工艺进行优化研究,正交实验结果表明:温浸法中四因素对刺五加总黄酮提取的影响顺序为:浸泡时间>乙醇浓度>水浴温度>料液比,刺五加总黄酮的最佳提取工艺:8倍体积80%乙醇浸泡1.5 h水浴温度70℃,这些提取条件的确定为中药刺五加的大规模开发和应用提供了科学资料和依据。     

椪柑皮多糖提取工艺研究

以广西特色水果——椪柑的果皮为原料,用水提取法提取其果皮中的生物有效成分——多糖.单因素试验和正交试验结果表明,该方法最佳提取条件为:料液比1:20,提取温度70℃,提取时间2h,提取次数2次,在此条件下椪柑皮多糖得率为5.35%.极差分析结果表明,影响多糖得率的各因素顺序依次为:料液比>提取温度>提取时间.     

正交试验法优化栀子多糖的提取工艺

为了研究栀子多糖的最佳提取工艺,利用正交实验对栀子多糖的提取工艺进行优化。在单因素实验的基础上选取实验因素与水平,设计四因素三水平正交实验。以栀子多糖提取率为指标,优化最佳提取工艺。试验结果表明:各实验因素影响主次顺序为提取次数料液比提取时间。栀子多糖的最佳提取工艺条件为提取次数3次,料液比1∶30,提取时间3.5h,采用此工艺条件提取多糖提取率为3.12%。     

乙醇回流法提取山豆根总生物碱的工艺研究

以山豆根为原料,利用乙醇回流法提取山豆根总生物碱,通过考察乙醇浓度、料液比、提取时间、提取次数四个单因素和L9(34)正交试验设计,对山豆根总生物碱的提取工艺进行优化。结果表明:影响山豆根总生物碱提取含量的各因素主次顺序为:乙醇浓度(A)>料液比(B)>提取时间(C)>提取次数(D),优选出的最佳提取工艺组合为:A2B2C3D2,即乙醇浓度为40%,料液比为1∶20,提取时间2h,提取2次。在此条件下,山豆根总生物碱的提取含量为16.8537 mg.g-1。     

沙棘叶水溶性多糖的提取工艺

通过采用95%乙醇回流脱脂-热水提取-乙醇沉淀的提取方法,在单因子实验的基础上进行正交实验,确定沙棘叶水溶性多糖的最佳提取工艺条件为温度70℃,时间2h,料液比为1:8.多糖最大得率为24.02%.     

黄柏中总生物碱的提取工艺优化

目的 通过正交法来确定黄柏总生物碱不同溶剂提取的最佳工艺.方法 以黄柏为原料,分别以水、乙醇为提取剂,提取黄柏生物碱.采用单因素试验,按照所给定的条件和生物碱含量测定方法,进行不同的提取时间、提取温度、料液比、乙醇浓度的单因素实验,考察了各因素对生物碱提取率的影响.根据单因素实验得出的显著条件,以盐酸小檗碱含量为考察指标,利用L9(33)正交实验方法优选提取工艺,确定最佳工艺条件.结果 以水为提取剂的最佳工艺条件组合是100 ℃水浴下提取次数为4次,提取时间为2.5 h,料液比1:16.提取的盐酸小檗碱含量是46.55 mg/g.乙醇为提取剂的最佳工艺条件组合是70 ℃水浴下乙醇浓度为70 %,料液比1:12,提取时间为80 min,提取次数为3次.提取的盐酸小檗碱含量是68.49 mg/g.结论 提取工艺设计合理,优选的工艺稳定可行,操作简便,提取剂为乙醇比水的提取时间短,节省能源,总生物碱提取率高32.03%.     

桑叶多糖提取工艺优化研究

设计了三因素三水平正交试验,对桑叶多糖的提取工艺进行了优化研究,确定出桑叶多糖提取的最佳工艺条件为:料液比1∶9,提取时间90min,提取温度90℃,通过实验验证该工艺条件提取桑叶多糖,多糖得率为8.08%,与三因素三水平正交试验所有实验组对照,大于正交试验中9个组合提取率,这些条件的确定为桑叶的大规模开发和应用奠定了基础。     

微波辅助提取虎杖中白藜芦醇的工艺研究

试验以虎杖白藜芦醇的提取率为指标,选择乙醇浓度、微波处理时间、料液浸泡时间以及料液比4个因素分别进行单因素试验,得出各因素对提取率的影响大小依次为:料液比>微波处理时间>乙醇浓度,而浸泡时间在实验范围(1h)内基本无影响.对影响较大的三个因素采用L9(33)正交试验设计确定最佳提取工艺:乙醇浓度为60%,微波提取时间为80s,料液比为1:10(g:mL),在最佳工艺条件下虎杖白藜芦醇提取率最高可达0.423%.     

大别山香蜜果总黄酮的提取工艺研究

研究大别山香蜜果黄酮提取工艺条件。采用单因素试验确定各因素对提取工艺的影响,正交试验确定最佳工艺条件。最佳提取工艺为:料液比为1∶30,提取次数为3次,提取时间为3 h,乙醇浓度为70%。影响大别山香蜜果黄酮提取工艺的主次顺序依次为:提取次数提取时间乙醇浓度料液比。为大别山香蜜果研究和制剂生产提供参考。     

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