Solenites murrayana L.et H.在甘肃窑街煤田的发现及其地质意义

在甘肃窑街中侏罗统窑街组发现了银杏类植物化石的重要代表穆雷似管状叶Solenites murrayana L．et H．，其外形显示出不分叉的细线形叶片，宽度小于1mm．根据室内实验对其表皮构造进行了研究，主要特征是：上表皮稍厚，细胞较大，多呈矩形，纵向延伸，具毛基；下表皮较薄，细胞相对小于上表皮细胞，不规则多边形；气孔器双生型，气孔定向排列，但不相连成带状；副卫细胞角质化程度较强，毛基较发育．Solenites murrayana的气孔参数可与现存最近对应种Ginkgo biloba的气孔参数进行对比，并可用来推论中侏罗世的古大气CO2浓度．     

吉林省接骨木属叶表皮微形态研究

接骨木属植物具有较高的食用、药用及经济价值,分布较分散.为探知接骨木属分种之间的亲缘关系,利用扫描电镜对吉林省接骨木属叶表皮微形态进行定性描述及主成分分析和聚类分析.结果表明:1)叶表皮具毛或无毛;上表皮细胞壁分为凸起和凹陷两种类型;气孔器有椭圆形和狭长椭圆形两种类型;叶表皮气孔大小、密度和表皮毛长短及密度等均存在差异.2)主成分分析选出4个主成分,方差累计贡献率达到81.665%.3)聚类分析结果表明:吉林省接骨木属植物分为两大类群.第Ⅰ类为有毛类,包括毛接骨木和宽叶接骨木,表现为叶表皮两面均具毛;气孔器为狭长椭圆形;气孔周边条纹小于1μm;上表皮细胞壁凸起,细胞呈不规则形,垂周壁式样为波状.第Ⅱ类为无毛类,包括接骨木、钩齿接骨木、东北接骨木和朝鲜接骨木,表现为叶表皮两面均无毛;气孔周边条纹大于1μm;上表皮细胞为多边形,垂周壁式样为平直-弓形.利用叶表皮微形态特征,编制吉林省接骨木属分种叶表皮分类检索表,说明叶表皮微形态特征可以作为吉林省接骨木属种下分类的重要特征.     

喜树叶表皮结构

通过光学显微镜和扫描电子显微镜，观察了喜树成熟叶的表皮细胞、气孔器、表皮毛形态，以及上、下表皮细胞外壁上的角质膜和蜡质纹饰．结果表明，上、下表皮层的形态结构差异较大．仅下表皮有气孔分布，气孔类型属不规则类型，常可观察到两个气孔着生在一起．上、下表皮均分布有非腺性单细胞毛     

不同分布地天女木兰叶表皮微形态研究

天女木兰是集芳香、药用、食用和观赏于一体的珍稀濒危植物,呈"间断式"分布。为探知天女木兰种下分类及其亲缘关系,利用扫描电镜对7个分布地天女木兰叶表皮微形态特征指标进行定性描述及主成分分析和聚类分析。结果表明:1表皮细胞分为浅波状和深波状两种类型;气孔器为椭圆形,分为凸起和凹陷两种;叶表结晶体有圆球形和长柱形;表皮毛密,分为单细胞毛、单列双细胞毛和单列多细胞毛3种类型;叶表皮气孔大小、密度和表皮毛长短及密度等均存在差异。2主成分分析选出3个主成分,方差累计贡献率达到87.394%。3聚类分析结果表明,7个分布地天女木兰种群分为两类。第Ⅰ类包括吉林石湖和河北祖山的天女木兰,表现为叶下表皮细胞呈浅波状,气孔密度小,气孔凸起,气孔长轴小于10μm,叶表结晶体呈圆球形;第Ⅱ类包括浙江清凉峰、安徽黄山、贵州雷公山、贵州麻江和广西猫儿山的天女木兰,表现为叶下表皮细胞多呈深波状,气孔密度大,气孔多凹陷,气孔长轴大于10μm,叶表结晶体呈长柱形。这表明各天女木兰间的亲缘关系远近与地理分布相关,叶表皮微形态特征可作为种下分类和探讨天女木兰种群间亲缘关系的重要特征。     

蕨麻试管苗与土培苗叶表特征比较

用透明胶法对蕨麻试管苗与土培苗叶表特征进行了观察比较。结果表明:土培苗与试管苗的表皮毛,均属单细胞、直的不分支的毛;表皮细胞形状:表面观,上表皮细胞均呈多边形,垂周壁平直、弓形,下表皮细胞不规则,垂周壁深波状;从气孔形态来看,试管苗气孔呈近圆形,土培苗气孔呈椭圆形,且试管苗气孔大小和开度都明显大于土培苗。同一叶片其下表皮气孔密度大于上表皮,试管苗与土培苗两者叶片下表皮气孔密度差异不显著。     

冬青属植物的叶表皮特征及其分类学意义

利用光学显微镜对102种冬青属植物的叶表皮特征进行了观察.结果表明:不同种冬青属植物的叶表皮特征既具有一定的相似性(如气孔器下生),据大小可分为正常气孔器和大气孔器,气孔器类型以双环列型为主,其次为环列型、三环列型和辐射型,下表皮具有退化大气孔器、簇状木质化细胞和瘿状结构;也具有一定的差异性,如叶表皮细胞的大小、形状、垂周壁形态和表面纹饰以及表皮毛的有无和长度.冬青属叶表皮特征的共同点表明冬青属是一自然类群,而其不同点说明叶表皮的某些特征可以作为种间分类的依据.因此,冬青属的叶表皮特征具有分类学意义,能为该属现生植物的系统分类、化石植物鉴定和系统演化研究提供可靠的证据.     

肾蕨叶表皮结构和气孔器发育的研究

在光学和电子显微镜下对肾蕨(Nephrolepis auriculata (L.)Trimen)叶表皮结构和气孔器发育进行了观察.肾蕨成熟叶表皮细胞呈不规则形,含有叶绿体.气孔器仅存在于下表皮,每个气孔器有2个保卫细胞,但副卫细胞3～6个不等.仅有2个副卫细胞和保卫细胞同源.保卫细胞和副卫细胞都含有叶绿体.气孔器的发育过程可分为3个主要时期:1)保卫细胞母细胞形成期;2)气孔器幼期;3)气孔器成熟期.在扫描电镜下观察,覆盖在表皮基本细胞和气孔器细胞外壁的角质膜呈波纹状.     

福建柃属植物(山茶科)叶表皮特征的比较研究

观察研究福建山茶科柃属18种1变型植物的叶表皮特征,统计并测量了气孔类型、气孔大小、气孔密度等有关特征.结果表明:该属植物的气孔为圆形或椭圆形,仅分布在下表皮,且多为无规则型,也有不等细胞型;叶表皮细胞形状有不规则形、不规则多边形;垂周壁较平直、浅波状、波状或深波状.在光镜下柃属植物在气孔大小、密度方面有明显不同,在表皮细胞形态、垂周壁样式和表皮毛等特征上差异较大,可作为种间区别的重要依据.     

蚕豆上、下表皮气孔运动光/暗响应机制

比较了光/暗对蚕豆上、下表皮气孔运动的调节作用.结果显示:光/暗调控的蚕豆上、下表皮气孔运动均涉及保卫细胞H2O2、NO、Ca2+、促分裂原活化蛋白激酶激酶(MAPKK)、钙依赖蛋白激酶(CDPK)和酪氨酸蛋白磷酸酶(PTP)的变化,下表皮气孔对光/暗更敏感,而且暗中下表皮保卫细胞H2O2、NO、Ca2+、CDPK和PTP水平高于上表皮保卫细胞.另外,胞内Ca2+库Ca2+释放对暗诱导下表皮保卫细胞Ca2+增加的效应显著大于对暗诱导上表皮保卫细胞Ca2+增加的效应.     

地榆叶的表观结构植纹鉴定研究

通过研究地榆成熟叶片表皮结构,为地榆的鉴定提供了可靠依据。根据相关性的分析发现气孔仅在下表皮且随机分布,保卫细胞半月形,上表皮的表皮细胞长度、宽度、周长和面积的数值均较下表皮大,上表皮细胞长宽比为1.76±0.62,下表皮细胞长宽比为1.92±0.48。相关性分析表明:保卫细胞宽度与保卫细胞面积呈显著负相关(r=-0.724,P0.05),保卫细胞宽度与表皮细胞周长呈显著负相关(r=-0.723,P0.05),保卫细胞面积与表皮细胞周长呈极显著正相关(r=0.999,P0.01)。根据以上结果可得出:叶表皮细胞形状、气孔指数、气孔大小、相关性等特征可以作为地榆分类鉴定的依据的结论。     

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.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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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.     

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     

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。