我国东部亚热带地区植被地理及大农业发展的方针

我国东部亚热带可分为过渡性亚热带和典型亚热带两部分.在偏北的过渡性亚热带内自然植被以含有常绿灌木层的落叶阔叶林为主,也有一些落叶阔叶一常绿阔叶混交林;冬麦和夏稻为一年两作制,常见梨、桃果园,而常绿果树如柑桔只见于局部小环境.在南部的典型亚热带内常绿栎林生长在酸性红黄壤上,而石灰岩土上则为落叶阔叶一常绿阔叶混交林.经常有双季稻和柑桔、茶、油茶、油桐的载培.亚热带的最南部主要为由茶科、樟科、金缕梅科、壳斗科等常绿阔叶树种所组成的杂木林,许多优良品质的柑桔类最适宜栽培.此外,要重视亚热带地区内许多湖泊的保护、开发和合理利用.     

福建建瓯万木林常绿阔叶林的基本特征

本文对福建省建瓯万木林自然保护区常绿阔叶林的植物区系成分、群落外貌和结构做了初步分析。 调查植物计58科100属140种。植物种类以樟科、壳斗科、未兰科、山茶科、杜英科和山矾科为主。对种子植物属的地理成分统计表明,热带分布的地理成分占总属数的73％,温带分布的则占24.4％。而种的地理成分则以中国亚热带特有分布为主,占总种数的61.5％。 常绿阔叶林中高位芽植物占86.4％,以常绿成分为主。叶性则以中小型叶、革质、全缘单叶为主。群落结构较完整,可分林木、下木和草层等,藤本植物较发达,一些树木有小型板状根发育,为中亚热带较典型的常绿阔叶林。     

浙江省常绿阔叶林的基本特征(一)

文章根据对浙江省五个地点的常绿阔叶林的调查,对其种类成份、外貌和结构的特征,作了汇总分析。在本文中,首先讨论了常绿阔叶林所在的环境条件,说明我国常绿阔叶林是在东亚亚热带季风气候条件下孕育的一种特殊的植被类型。根据五个地点21个样地的统计,组成浙江常绿阔叶林的维管束植物共约428种,分属于105科,225属。在双子叶植物中壳斗科、樟科、山茶科的种类最多,它们均是构成林木层的基本成份。群落的优势种集中在少数的属中。如壳斗科的 Castanopsis,Lithocarpus,Cyclob-alanopsis,Quercus,山茶科的 Camellia,Eurya,以及樟科的 Machilus,Cinnamomum,Lindera,Litsea 和杜鹃花科的 Rhododendron 以及蔷薇科的 Photinia 和 Prunus 等。同时还分析了常绿阔叶林区系的地理成份,分析表明它们与热带区系有着密切联系,尤其是与热带东南亚植物区系存在着较悠久的共同历史。温带、东亚分布类型的属的较高比例是我国东部亚热带常绿阔叶林的特征之一。中国亚热带特有种类的大量存在进一步表明了常绿阔叶林是我国亚热带地区的一种特有类型。     

浙江省常绿阔叶林的基本特征(一)

文章根据对浙江省五个地点的常绿阔叶林的调查,对其种类成份、外貌和结构的特征,作了汇总分析。在本文中,首先讨论了常绿阔叶林所在的环境条件,说明我国常绿阔叶林是在东亚亚热带季风气候条件下孕育的一种特殊的植被类型。根据五个地点21个样地的统计,组成浙江常绿阔叶林的维管束植物共约428种,分属于105科,225属。在双子叶植物中壳斗科、樟科、山茶科的种类最多,它们均是构成林木层的基本成份。群落的优势种集中在少数的属中。如壳斗科的Castanopsis,Lithocarpus,Cyclobalanopsis,Quercus,山茶科的Camellia,Eurya,以及樟科的Machilus,Cinnamomum,Lindera,Litsea和杜鹃花科的Rhododendron以及蔷薇科的Photinia和Prunus等。同时还分析了常绿阔叶林区系的地理成份,分析表明它们与热带区系有着密切联系,尤其是与热带东南亚植物区系存在着较悠久的共同历史。温带、东亚分布类型的属的较高比例是我国东部亚热带常绿阔叶林的特征之一。中国亚热带特有种类的大量存在进一步表明了常绿阔叶林是我国亚热带地区的一种特有类型。     

福建梅花山国家级自然保护区常绿阔叶林的群落学特征

福建梅花山国家级自然保护区的常绿阔叶林是典型的中亚热带常绿阔叶林之一.9 600 m2样地的调查与分析表明:群落内共有维管束植物258种,其中种子植物228种,隶属于87科156属,植物的科属组成丰富.群落内区系地理成分复杂,热带与泛热带植物区系成分比例明显大于温带与泛温带区系成分,具热带亚热带性质.群落中,中小型革质、全缘、单叶、常绿、木本、高位芽植物是决定其外貌主要因素.群落成层现象明显,可分为2个乔木亚层、1~2个灌木亚层和草本层,层间植物较为丰富.通过不同区域常绿阔叶林的比较,无论区系组成与成分还是群落外貌和结构均体现了中亚热带南缘常绿阔叶林的特征.     

浙江天童及周边地区常绿阔叶林退化群落的植物区系分析

浙江天童及周边地区的常绿阔叶林退化群落包括五个类型：常绿阔叶林退化前期群落、落叶阔叶林群落、针阔混交林群落、针叶林群落以及灌丛群落.通过对退化植被各群落类型的区系分析，得出了天童地区常绿阔叶林退化群落的区系组成特征，具体如下：（1）天童及周边地区退化植被的植物区系包括72科138属204种，其物种多样性低于常绿阔叶林的成熟群落；（2）本植物区系地理成分与常绿阔叶林成熟群落一致，表现了明显的亚热带植物区系性质，是热带向温带的过渡；（3）人类的干扰导致了各退化群落中国特有成分的下降；（4）各退化群落类型与常绿阔叶林成熟群落保持了较高水平的科、属和种的相似性.综上所述，天童及周边地区退化植被保持了亚热带常绿阔叶林的植物区系特征，从植物区系学的角度来看，具有恢复为地带性常绿阔叶林成熟群落的潜力.     

天目山第三纪孑遗植物缺萼枫香的群落特征及其生态学意义

通过选择代表性地段,设置第三纪孑遗植物缺萼枫香群落样方,开展群落学调查,分析群落的物种组成、外貌及结构特征等.研究结果表明,群落中生长维管束植物177种,分属65科128属,科属组成较为复杂.在该地区,物种的区系地理成分丰富多样,以温带成分占优势,并含有较多古老属种.群落外貌由中、小型草质单叶的高位芽植物占优势,其中落叶成分所占比例相对较高.群落垂直结构分化明显,可以分为乔木层、亚乔木层、灌木层和草本层,树冠分布较为连续.天目山缺萼枫香群落是以落叶成分为主的、由中小型草质单叶的高位芽植物决定的常绿落叶阔叶混交林,具有古老性和残遗性.缺萼枫香林集中分布在中亚热带南部和中亚热带北部,种类组成表现较强的替代规律,随纬度升高落叶成分比例增加,常绿树种由适生冷凉气候的种类替代,常伴生有丰富的第三纪孑遗植物.应进一步研究缺萼枫香林群落的演替规律和演变历史,探讨枫香属植物的起源和进化以及冰期对第三纪森林的影响.     

浙江省常绿阔叶林的基本特征(二)

浙江省常绿阔叶林的基本特征,除在本文(一)中所述外,还包括以下诸方面:三、浙江省常绿阔叶林的外貌特征常绿阔叶林首先就是从其终年常绿和具有浑圆的树冠而区别与其它类型。群落外貌主要是由群落的生活型组成、叶的性质以及周期性所决定的。(一)生活型群落的生活型组成是决定群落外貌的主要因素,它反映了群落的特殊生境以及群落内部可能产生的竞争。对前述五个地区所有样地的全部植物种类,按 Raunkiaer 生活型分类标准进行统计(图1)的结果表明,其中以高位芽植物占明显的优势(64.1%,如加上藤本植物的12.6%,可达76.7%),其次为地     

圩墩遗址古木研究

通过对圩墩遗址出土古木１５个树种的鉴定，确定五，六千年前圩墩存在过落叶－常绿阔叶混交林带。该林带是温带针，阔叶混交林带与亚热带常绿阔叶林带之间的过渡区，属温暖，湿润的亚热带植被类型。落叶阔叶树有壳斗科的麻栋和槲栎类，金缕梅科的枫香，漆树科的黄连木及豆的黄檀等树种。常绿阔叶树有茶科的荷木，豆科的红豆树及木犀科的蜡树等树种。     

南京植被性质初探

南京地处亚热带向暖温带的过渡区,长期以来,在自然区划和植被区划中都被确认为属于北亚热带常绿阔叶与落叶阔叶混交林地带。这个地带的确定,与秦岭——淮河线被确定为亚热带常绿阔叶林带和暖温带落叶阔叶林带的分界线有密切的关系。在中国植被区划中南京位于常绿阔叶林带的北部边缘,是常绿阔叶林向落叶阔叶林的过渡地区,植被类型属常绿阔叶与落叶阔叶混交林类型。究竟在南京有没有常绿阔叶与落叶阔叶混交林群落存在?南京     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

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.     

A computer generator for randomly layered structures

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

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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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

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。     

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.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

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