白花蛇舌草苷类成分的研究

从茜草科植物白花蛇舌草（Hedyotis diffusa Willd）中通过溶剂提取、硅胶柱层析、Sephadex LH-20柱层析和制备薄层层析等方法分得6个苷类化合物。波谱分析（核磁共振氢谱、碳谱和质谱）确定它们的结构分别为E-6-O-p-methoxy cinnamoyl scandoside methylester（1），Z-6-O-p-methoxycinnamoyl scandoside methyl ester（2），asperuloside（3），asperulosidic acid（4），乙基-β-D-吡喃葡萄糖苷（ethyl β-D-glucopyranoside，5）和胡萝卜苷（daucosterol，6）。化合物5为首次从本植物中分到。     

补骨脂化学成分的研究

从中药补骨脂(Psoraleacorylifolia)种子中通过溶剂提取、硅胶柱层析、SephadexLH-20柱层析和制备薄层层析等方法分得四个化合物。波谱分析(核磁共振氢谱、碳谱和质谱)确定它们的结构分别为补骨脂查耳酮(1,bavachalcone)、补骨脂色烯素(2,bavachromene)、松醇(3,pinitol)和对羟基苯甲醛(4,p-hydroxybenzaldehyde)。化合物3系首次从补骨脂中分得。     

蛇足石杉化学成分的研究

从云南屏边产石杉科植物蛇足石杉(Huperzia serrata(Thunb.)Trev.)中通过溶剂提取、硅胶柱层析、Sephadex LH-20柱层析和制备薄层层析等方法分得11个化合物,包括6个生物碱、3个三萜和2个甾体。波谱分析(核磁共振氢谱、碳谱和质谱)确定它们的结构分别为石杉碱甲(1),石杉碱乙(2),石杉碱庚(3),马尾杉碱乙(4),8β-羟基马尾杉碱乙(5),lycoposerramine D(6),serratenediol(7),21-epi-serratenediol(8),serratenediol-3-acetate(9),β-谷甾醇(10)和胡萝卜甙(11),均为首次从云南产蛇足石杉中分离得到。     

基于拟分布函数的中药色谱指纹图谱的相似性分析

针对中药色谱指纹图谱中色谱峰面积值存在较大变异性的问题,从拟分布函数的角度介绍了一种新的分析方法。采用秩变换将色谱峰面积值转化为相对秩次,然后通过一系列变换将原数据转换成拟分布函数的形式,再利用柯尔莫哥洛夫检验实现不同类别样品的色谱指纹图谱之间的相似性分析。通过对北马兜铃和南马兜铃样品的比较,说明了该方法有较好的灵敏度和稳健性,因而是比较合理的。     

基于HPLC的细辛挥发油中马兜铃酸A的检测分析

采用HPLC对细辛挥发油提取物中马兜铃酸A进行检测分析,并对其含量测定方法进行研究.方法:以十八烷基硅烷键合硅胶为色谱分离填充剂,确定细辛挥发油提取物中马兜铃酸A的检测方法,流动相为乙腈-甲酸(1.0%,35∶65);流速为1.0mL/min;检测波长250nm;柱温35℃.结果:该测定方法系统适用性良好,马兜铃酸A在体积浓度为0.505~2.525μg/mL范围内线性关系良好(r=0.9994),且回收率较高,经分析比较,该细辛挥发油提取物中检测未含有马兜铃酸A.结论:该测定方法灵敏准确,适用于细辛挥发油提取物中马兜铃酸A的测定分析,细辛挥发油提取物的使用较为安全.     

基于拟分布函数的中药色谱指纹图谱的相似性分析

针对中药色谱指纹图谱中色谱峰面积值存在较大变异性的问题,从拟分布函数的角度介绍了一种新的分析方法。采用秩变换将色谱峰面积值转化为相对秩次,然后通过一系列变换将原数据转换成拟分布函数的形式,再利用柯尔莫哥洛夫检验实现不同类别样品的色谱指纹图谱之间的相似性分析。通过对北马兜铃和南马兜铃样品的比较,说明了该方法有较好的灵敏度和稳健性,因而是比较合理的。     

蒙药森登-4有效部位化学成分的研究

采用硅胶柱层析、制备薄层层析、pharmadex LH-20柱层析法分离,通过理化性质和波谱法鉴定化合物结构,从蒙药森登-4的有效部位中分离得到8个单体化合物,分别为:大黄酚(1)、大黄素甲醚(2)、β-谷甾醇(3 )、豆甾醇(4)、大黄素(5)、2,5-二甲氧基苯醌(6)、槲皮素(7) 、栀子苷(8),对蒙药森登-4有效部位的化学成分进行研究,其中化合物1-6为首次从森登-4中分得,并且化合物1、2和5是首次从森登-4中分得蒽醌类成分,为阐释蒙药森登-4药效物质基础奠定了基础.     

马兜铃酸-A衍生物合成及其生物活性研究

从关木通中分离提取马兜铃酸-A,合成了两种新的马兜铃酸-A衍生物:1-O-马兜铃酰基-2,3,4,6-四-O-乙酰基-β-D-吡喃葡萄糖(Ⅱ)和1-O-马兜铃酰基-2,3,4,6-四-O-乙酰基-β-D-吡喃半乳糖(Ⅲ).元素分析、核磁共振、红外光谱表征了它们的结构,并对马兜铃酸-A及其衍生物(马兜铃内酰胺、马兜铃酸葡萄糖基酯、马兜铃次酸)进行了对S180肿瘤细胞作用的研究.     

马兜铃酸电喷雾质谱电离规律及其药材指纹图谱

应用电喷雾离子阱质谱(ESI-MS)研究马兜铃酸Ⅰ和马兜铃酸Ⅱ在ESI正离子检测方式下的一级质谱电离规律和二级质谱的碎裂规律,并对马兜铃属植物关木通和青木香对照药材中马兜铃酸提取物进行了电喷雾质谱分析.根据马兜铃酸类物质各分子离子峰的二级质谱碎裂规律和分子量信息对药材提取物中各组分进行了初步认证,并对其中11种已知主要马兜铃酸以选择离子检测(SIM)模式制定了关木通和青木香对照药材马兜铃酸提取物的指纹图谱.实验结果表明,马兜铃酸类物质具有相似的电喷雾质谱规律:一级质谱中,马兜铃酸类物质易形成二聚体与加合离子;失去-CO2碎片是马兜铃酸类物质二级质谱的共有特性.以选择离子检测(SIM)方式制定的关木通和青木香药材的电喷雾质谱指纹图谱,特征性强,图谱简单易于解释,重现性好.     

竹柏化学成分的研究

竹柏枝叶用氯仿提取,硅胶柱层析、MCI柱层析和Sephadex LH-20柱层析进行化学成分分离纯化,从中分离得到9个化合物.根据现代波谱技术和理化性质对化合物结构进行鉴定,鉴定结构分别为:nagilactone A(1)、4β,10β,15-trihydroxy-aromadendrane-10,15-acetonide(2)、amentoflavone(3)、bilobetin(4)、podocarpusflavone A(5)、quercetin(6)、(-)-catechin(7)、5α,6β-dihydroxysitosterol(8)和prinsepiol(9).其中化合物2、4、8和9为首次从该属中分离得到.     

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。