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《青海大学学报》2017,(4)
为了进一步优化紫花苜蓿中黄酮类物质提取工艺,选用青大1号紫花苜蓿盛花期青干草粉作为试验材料。实验采用超声辅助提取的方法提取紫花苜蓿中黄酮类物质,首先设计单因素实验考察料液比、超声温度、超声时间、酶解时间4个单因素对苜蓿提取率的影响,结果表明4个单因素处理分别对紫花苜蓿黄酮类物质提取率存在显著影响(P0.05)。以单因素试验结果为依据开展4因素(料液比、超声温度、超声时间、酶解时间)三水平正交试验。结果表明:影响黄酮类物质提取率的因素从大到小依次为料液比、超声时间、酶解时间、超声温度。综合分析获得最优提取条件为料液比1∶30,超声时间30 min,超声温度50℃,酶解时间1 h。超声辅助方法可以提高紫花苜蓿黄酮类物质提取率。 相似文献
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以金银花为试验原料,通过单因素试验和响应面法优化了酶法提取金银花多糖工艺,考察了酶用量、提取温度、液料比、提取时间对提取率的影响.结果表明,当酶用量为0.3%、提取温度为55℃、液料比为40 mL/g、提取时间为40 min时,金银花多糖提取率可达6.67%,且试验的重现性好,对于金银花等植物多糖的提取研究具有一定的参考价值. 相似文献
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超声波辅助酶法优选花生芽中白藜芦醇提取工艺 总被引:1,自引:0,他引:1
以花生芽为原料,采用纤维素酶-超声波复合处理从花生芽中提取白藜芦醇,结合单因素试验研究了酶的酶解温度、酶添加量、p H值、酶解时间和超声波对样品的处理温度、处理时间、乙醇浓度(体积分数)、料液比等8个因素对花生芽中白藜芦醇提取量的影响,并且通过正交试验确定最佳提取工艺。结果表明:花生芽中白藜芦醇最优提取工艺为花生芽粉为1.000g,酶解温度为60℃,酶添加量为0.2g,p H值为4.8,酶解时间为2.0h,超声波处理温度为60℃,乙醇浓度为70%,料液比为1∶40,超声波处理时间为50min,在此条件下花生芽中白藜芦醇的最大提取量为7.39mg/g,比传统的乙醇回流法提高了大约4.6倍。 相似文献
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采用酶法提取荷叶中的荷叶碱 总被引:2,自引:0,他引:2
钟世安 乔蓉 李维 袁周率 邓潇君 ZHONG Shi-an QIAO Rong LI Wei YUAN Zhou-lü DENG Xiao-jun 《中南大学学报(自然科学版)》2007,38(6):1135-1139
以晒干粉碎的荷叶为原料,采用纤维素酶预处理,稀盐酸浸提,超声波辅助提取,氯仿萃取方法提取荷叶碱。考察纤维素酶用量、酶解温度、酶解时间、酶解酸度、液料比、稀盐酸浸提时间、浸提液中盐酸浓度对荷叶碱提取率的影响,经紫外分光光度计检测所得荷叶碱浓度,确定最佳实验条件。研究结果表明,最佳提取工艺条件是:酶的用量为2.667×10-6mol/(s.g),酶解温度为50℃,酶解时间为2h,酶解酸度pH=5.0,液料比为30:1,浸提时间为16h,盐酸浓度为0.5%,荷叶碱的提取率达到1.105%。 相似文献
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采用了酶解辅助水法提取土茯苓总黄酮.以芦丁为标准品,用铝离子显色、紫外-可见分光光度法测定总黄酮含量.以总黄酮提取率为考察指标,通过单因素实验探讨酶用量、固液比、提取温度、提取次数对总黄酮提取率的影响,优化提取条件.结果表明最佳提取工艺条件为:酶用量2.0%、固液比例1:8、提取温度100℃、提取3次.最佳条件下,粗提物干粉得率为14.0%,干粉总黄酮含量为4.1%,总黄酮提取率为0.57%. 相似文献
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以干柚皮为原料,研究了纤维素酶辅助提取柚皮中果胶的工艺.分别讨论了纤维素酶用量、时间、温度和料液比等因素对果胶提取率的影响,并通过单因素及L9(34)正交试验,确定了当pH=2.0时从柚皮中提取果胶的最佳工艺条件为:纤维素酶用量0.15%,料液比1∶40,提取时间3 h,提取温度45℃,在此条件下果胶提取率达到6.02%. 相似文献
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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. 相似文献
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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. 相似文献
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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。 相似文献
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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. 相似文献
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Miao Maosheng 《华南师范大学学报(自然科学版)》2014,(6)
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- 相似文献
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Yang Weitao 《华南师范大学学报(自然科学版)》2014,46(6):137-138
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- 相似文献
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Bernard Kirtman 《华南师范大学学报(自然科学版)》2014,(6)
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 相似文献
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《上海师范大学学报(自然科学版)》2014,(5):550
<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 相似文献
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《吉林大学学报(理学版)》2014,(5):1105
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has 相似文献