双频超声强化对三七总皂苷提取的影响

采用双频超声（40kHz／25kHz）技术对三七总皂苷提取进行强化，选择乙醇质量分数、料液比、超声作用时间及提取温度因素进行正交试验，得出影响总三七总皂苷提取率的大小次序先后为：乙醇质量分数〉超声作用时间〉料液比〉提取温度，优选出双频超声提取最佳工艺条件：质量分数为80％的乙醇，超声作用时间为30min，料液比为1：20，提取温度为40℃．在这个最佳条件下试验，三七总皂苷提取率为82．41％．采用碘化钾溶液中碘的释放量来研究超声空化事件。结果表明：在相同的超声电功率下，双频超声释放碘的量远大于单频25kHz超声和单频40kHz超声释放的碘。     

异枝麒麟菜活性硫酸粗多糖的提取工艺优化

采用能有效保护抗病毒活性基团的直接水提法提取异枝麒麟菜活性硫酸多糖，通过正交试验研究了影响多糖得率的工艺参数：KCl质量分数、温度、时间、料液比；通过均匀试验研究了其中影响最大的因素的最佳水平．结果表明，温度和KCl质量分数为多糖得率的最大影响因素，其最佳水平分别为125℃和0．93％．结合实际情况，最佳提取工艺条件可为：浸提温度95～100℃、浸提时间6h、料液质量比1：90、KCl质量分数0．93％．     

正交法优化茶籽饼粕中茶皂素的提取工艺

采用正交实验法,从提取时间、温度、乙醇浓度、液料比4个因素出发对从茶籽饼粕中提取茶皂素的工艺进行了研究．以茶皂素得率和含量为指标,得出茶皂素的最佳提取条件为：浸提时间为5h,浸提温度为70℃,乙醇浓度为80％．料液比为9：1．     

微波法提取苦瓜叶中总黄酮

介绍了以苦瓜叶为原料用微波法提取总黄酮，通过正交试验对该方法进行了最佳条件的探讨．实验结果表明：以50％乙醇水溶液作提取溶剂，固液比1：35，微波照射2．5min，浸提时间45min，提取温度80℃，苦瓜叶中总黄酮提取率最高．     

月见草花黄色素提取工艺研究

对月见草花黄色素的提取条件进行了系统的研究，比较了无水乙醇、95％乙醇、乙醚、丙酮、乙酸乙酯、石油醚提取月见草花黄色素的效果.结果显示：以95％乙醇为最佳溶剂，95％乙醇提取液的λmax为394 nm.单因素试验和正交试验表明，温度对提取月见草花黄色素的影响较大，而浸提时间和料液比影响较小.提取的最佳工艺条件是：以体积分数95％的乙醇为浸提剂，按每0.2 g月见草花粉末加浸提剂30 mL的比例投料，在温度60 ℃下，浸提时间为4 h.月     

金银木叶中黄酮类化合物的定性分析

研究了浸提温度、时间、乙醇浓度、料液比等因素对金银木叶中黄酮类化合物提取效果的影响,确定了最佳单因素水平。正交实验确定了以乙醇为浸提剂的最佳提取工艺条件为:体积分数为0.60的乙醇,料液比1∶30,70℃,浸提4h。金银木叶中富含黄酮类化合物,颜色反应试验和紫外光谱分析初步表明,其主要成分为黄酮类和黄酮醇类。     

桂花色素提取工艺的优化研究

以桂花为原料,进行色素提取工艺的优化研究。对浸提剂、乙醇浓度、料液比、萃取时间及萃取温度这5个因素进行单因素和正交试验。结果表明,乙醇为最佳浸提剂,最大吸收波峰为330nm。桂花色素的最佳提取工艺条件为：85％的乙醇、料液比1：15、萃取时间80min、萃取温度80℃;在此工艺条件下,测得桂花色素的吸光度值为1．424。     

刺五加中刺五加皂甙提取条件的优化

刺五加为五加科植物，其所含刺五加皂甙有极强的药理作用。根据刺五加皂甙的理化性质，采用分光光度法在不同提取剂、不同料液比、不同温度、不同时间下对刺五加提取液中皂甙含量进行测定，最后确定刺五加皂甙提取的最佳条件为：以75％乙醇为提取剂，料液比为1：6，温度为80℃，提取6h。     

苦瓜总皂苷提取条件优化及不同部位的含量分析

文章采用乙醇提取苦瓜冻干粉中的总皂苷,选定乙醇质量分数、时间、料液比和温度作为单因素考察,将苦瓜总皂苷提取率作为考察指标。通过三因素三水平的正交实验,确定苦瓜总皂苷的最佳提取条件。实验结果表明,提取工艺条件为乙醇质量分数60%,料液比1∶7,提取时间3h,此时皂苷粗制品的得率为2.37%。在此基础上,对苦瓜果肉和苦瓜瓤分别进行分析,结果表明苦瓜果实的不同部分含有的总皂苷得率差异显著(P0.05)。     

超声波提取黄芪中总黄酮工艺研究

研究比较了超声波法、微波法、乙醇提取法等工艺提取黄芪总黄酮的效果,得出超声波法提取黄芪总黄酮的工艺最佳．以提取温度、提取时间、料液比、乙醇体积分数为考察因素,黄芪总黄酮提取率为考察指标,采用止交试验法优化黄良总黄酮提取工艺．结果表明,最佳工艺条件为：超声波提取温度为65C、提取时间30min、料液比为1：15（g／mL）、乙醇体积分数为65％,总黄酮的提取率为0．418％,是微波提取法的1．31倍,乙醇提取的1．69倍．     

An Index mechanism for multi-scale view in spatial databases

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.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。