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1.
用正交实验和单因素实验考察了索氏提取不同有机溶剂萃取法、不同条件乙醇回流提取法和超声提取法对银杏花粉总黄酮含量的影响,结果表明:正丁醇萃取法总黄酮含量明显高于乙酸乙酯萃取法;回流提取,以12倍量75%乙醇回流提取1.5 h,2次为最佳条件;超声提取用60%乙醇3、0 min为宜.  相似文献   

2.
苦丁茶中熊果酸的提取工艺   总被引:10,自引:0,他引:10  
在苦丁茶中提取熊果酸的过程中,采用正交实验研究了乙醇体积分数、液固比、提取时间、提取温度、提取次数等对熊果酸浸出率的影响.正交实验的方差分析结果表明:对于熊果酸的浸出率,提取时间的影响最大,乙醇浓度和固液比的影响次之;最佳回流提取工艺条件为:在85℃水浴中,以90%(体积分数)乙醇水溶液为提取液,液固比为14 : 1,提取2次,每次提取2.5 h时,熊果酸的浸出率可达到1.44%.  相似文献   

3.
甘草中甘草酸的多级逆流提取技术研究   总被引:1,自引:0,他引:1  
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.  相似文献   

4.
搅拌回流法和微波法从花生壳中提取黄酮   总被引:2,自引:0,他引:2  
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.  相似文献   

5.
研究枸骨叶中熊果酸的最佳提取工艺条件.在单因素试验的基础上,采用正交试验设计法,选择乙醇浓度(A)、固液比(B)、提取时间(C)为因素,每因素各取三水平,按 L9(34)正交表进行实验.结果表明:影响提取效果各因素为乙醇浓度>提取时间>固液比.其最优提取工艺条件为用8.5倍量φ=95%乙醇,于80℃加热回流提取2次,第一次2 h,第二次1.5 h.  相似文献   

6.
绞股蓝皂苷提取工艺的研究   总被引:1,自引:0,他引:1  
采用正交设计试验研究了浸提条件(乙醇浓度、提取温度、提取时间、料液比),得到最佳的冷凝回流法提取条件是以30倍量浓度为80%乙醇在90℃水浴中回流提取3次,每次1h,最高得率为0.1646%,超声提取法的最佳提取条件是以20倍量的80%乙醇超声提取1次,每次30min,最高得率为0.4344%。  相似文献   

7.
金花葵中总黄酮的分离提取及含量测定   总被引:2,自引:0,他引:2  
利用索氏提取法分离提取金花葵中的总黄酮,考察了乙醇浓度、料液比、提取时间及提取温度等因素的影响,通过正交实验进行优化,结果表明,影响金花葵总黄酮提取率的各因素的主次顺序是:乙醇浓度料液比提取温度提取时间,同时确定了最佳实验工业参数:乙醇浓度为60%,固液比为1∶35,提取时间3.0 h,提取温度80℃.在此最优试验条件下,金花葵总黄酮提取率可达到4.55%.最后,采用芦丁标准曲线测定了金花葵中总黄酮的含量为2.72%.  相似文献   

8.
青海豌豆多糖提取工艺的研究   总被引:1,自引:0,他引:1  
以青海豌豆为原料,采用正交试验法对豆渣中水溶性豌豆多糖的提取工艺进行研究.结果表明,豌豆多糖提取的最佳条件为提取温度80℃,固液比1∶10,提取时间4.5h×3.在最佳提取工艺条件下,豌豆多糖的提取率为48.67%.  相似文献   

9.
采用热回流提取法,经过粉碎、热回流提取、浓缩、酸沉、过滤等实验过程从甘草中提取粗提甘草酸。以甘草酸的提取率为指标,通过正交实验设计考察乙醇浓度、NaHCO_3添加量、液料比、提取时间和提取温度对甘草酸提取率的影响。结果表明,甘草酸的最佳提取条件为:乙醇浓度60%、NaHCO_3添加量0. 4%、液料比15∶1、提取时间2. 5 h、提取温度60℃。在最佳条件下甘草酸的平均提取率为33. 27%。  相似文献   

10.
小蓬草总黄酮提取条件及含量测定   总被引:4,自引:0,他引:4  
采用聚酰胺吸附-硝酸铝显色法,以芦丁为标样,在510nm处测总黄酮含量,通过正交实验,在不同乙醇体积分数(50%、65%、80%),不同固液比(1∶20、1∶35、1∶50),不同提取时间(1h、2h、3h)和不同提取温度(40℃、60℃、80℃)条件下,得出小蓬草叶总黄酮提取最佳条件为:在80℃条件下乙醇体积分数65%,固液比1∶50,提取3h.并用该最佳提取条件分别提取小蓬草根、茎、叶中的黄酮类化合物,测其含量分别为0.773%、0.380%、1.185%.  相似文献   

11.
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   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
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   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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   

16.
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   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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