响应面法优化超声波辅助提取狭叶荨麻黄酮和木脂素工艺

通过响应面法优化超声波提取狭叶荨麻中黄酮和木脂素的工艺,以黄酮和木脂素得率为指标,在考察乙醇浓度、提取时间、提取温度、提取次数和料液比的基础上,利用响应面法进行3因素3水平的试验.结果表明:最优条件是乙醇质量分数为87.62%、提取温度为54.15℃、料液质量体积比为1∶45.64(mg∶mL)、提取时间50min、提取3次;在该条件下,黄酮提取率10.875mg.g-1,木脂素提取率1.100mg.g-1;证实响应面法在同时提取2种以上中药有效成分时可以得到较为理想的结果.     

响应面法优化洋金花中东莨菪碱的提取

运用响应面法进行实验设计,对洋金花中东莨菪碱在超声提取过程中的各因素进行考察优化.采用HPLC法测定东莨菪碱的质量浓度,以盐酸浓度、提取时间、液料比为考察因素,东莨菪碱提取率为响应值,用Box-Behnken响应面法设计提取工艺实验,建立预测方程,优化提取工艺.结合实际可操作性,确定最佳提取条件为:盐酸浓度3 mol·L~(-1),提取时间43 min,液料比25 mL·g~(-1).实验结果显示,实际值与预测值的偏差为2.76%,相关性良好,说明对洋金花中东莨菪碱的提取进行响应面法优化合理可行.     

正交试验优化玉米皮中阿拉伯木聚糖提取条件

本文在考察温度、时间、碱液浓度和料液比四个单因素对阿拉伯木聚糖得率影响的基础上，采用正交试验对阿拉伯木聚糖的碱提工艺条件进行了优化。结果表明，在提取温度80℃、时间4h、NaOH浓度0．3mol／L、料液比1：30的条件下，阿拉伯木聚糖的得率达到最大值2457％。     

超声波法提取玉米芯木聚糖的研究

考察了用超声波法提取玉米芯木聚糖时各因素对提取率的影响。并通过正交实验确定了提取过程的最优条件：时间30min,原料质量分数3.23%,功率280W,温度60℃。在此条件下,用7%（质量分数）的NaOH提取,木聚糖的提取率可达29.34%。玉米芯经过水煮后,木聚糖提取率为33.01%。与常规提取法相比,超声波法具有耗时少的优点。     

柚叶多酚的提取工艺优化

本文以柚叶为原料,研究从柚叶中提取多酚的工艺,利用单因素和响应面试验对提取工艺中影响柚叶多酚提取率的工艺参数(乙醇浓度、浸提时间、液料比、提取温度)进行了分析与优化.结果表明,柚叶多酚的最佳工艺条件为:乙醇浓度60%、浸提时间100 min、液料比20 m L·g-1、提取温度70℃,柚叶多酚提取率为22.76 mg·g-1,与模型预测值(22.88 mg·g-1)相比,其相对误差为0.52%,验证了该模型的有效性和实用性.     

响应面法优化纤维素酶提取三叶青多糖的工艺研究

为了优化三叶青多糖的酶法提取工艺,选用纤维素酶提取三叶青多糖。通过单因素试验法和响应面分析法,考察酶加量、酶解温度、酶解时间、水料比这4个因素对三叶青多糖提取率的影响。得到的最佳提取条件为:酶加量0.274%,酶解温度60.5℃,酶解时间62.4 min,水料比25.8∶1(体积∶质量,mL/g),此条件下三叶青多糖的实际提取率为10.47%,与理论最佳提取率10.43%相比,相对误差为0.38%。此结果表明,运用响应面法优化得到的工艺条件准确可靠,能够真实地反映各因素对三叶青多糖提取率的影响,该提取工艺稳定合理、客观可行。     

响应面法优化白兰叶总黄酮的提取工艺研究

为优化白兰叶总黄酮的提取工艺,在单因素实验的基础上,以白兰花叶总黄酮提取率为响应值,进行响应面优化。结果表明白兰叶总黄酮提取的最佳工艺条件为:提取温度73℃,提取时间130 min,乙醇浓度60%,液料比17 m L/g,在此条件下,测得白兰叶总黄酮的提取率为9.21%,与理论预测值相对误差为1.39%,验证了回归模型的有效性,说明回归模型拟合度好,准确率高,可靠性强,可用于白兰叶总黄酮提取工艺的优化。     

响应面优化龙胆草中龙胆苦苷提取工艺的研究

目的:利用响应面优化龙胆草中龙胆苦苷的提取工艺.方法以龙胆草为原料,考察了乙醇浓度、提取时间、料液比及提取温度对龙胆草中龙胆苦苷提取率的影响,在单因素试验的基础上利用Design Expert数据处理软件进行响应面实验设计,确定龙胆草中龙胆苦苷的最佳提取工艺.结果及结论:在乙醇浓度为70%,提取时间为3h,提取温度71.5℃,料液比1:10时提取率最佳,龙胆苦苷提取率可达5.56%.     

响应面法优化多刺绿绒蒿中总黄酮的提取工艺

利用响应面法优化多刺绿绒蒿中总黄酮的提取工艺.在单因素试验的基础上,选择乙醇浓度、液料比和提取时间为自变量,以总黄酮提取率为响应值,进行Box-Behnken中心组合实验设计,采用响应面法(RSM)分析这些因素对总黄酮提取率的影响.响应面优化设计得出的最佳工艺为乙醇浓度64%,液料比30:1,提取时间66min,总黄酮提取率达1.521%.     

甘草中甘草酸的提取工艺研究

采用氨性醇提取法,经粉碎、抽提、过滤等工艺过程从甘草中提取甘草酸,并利用响应面试验设计考察提取温度、提取时间、氨水浓度、乙醇浓度4因素对甘草酸提取率的影响。结果表明,甘草酸的最佳提取条件是:提取温度为40.28℃,提取时间为5.84 h,氨水浓度为0.41%,乙醇浓度为16.78%。最优条件下粗甘草酸的提取率达到66.40%。     

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