重庆市长寿区土地利用格局及动态变化分析

利用景观生态学原理,基于RS和GIS技术,对研究区1995年和2001年土地利用格局进行分析,结合景观格局指数和景观动态模型分析了研究区土地利用变化趋势及速率.结果表明:①林地、水田和旱地构成研究区内优势景观,1995-2001年耕地减少,城市用地增加.②山地旱地破碎化程度最高;有林地和丘陵水田破碎度较小,景观较完整;③湖泊和农村居民点斑块分布较散,同类间干扰小.城镇用地斑块距离增大,城镇扩张明显.④2001年景观异质性比1995年较高.⑤水域、城镇用地和耕地变化速率大,整体土地利用变化较小.     

近30年来哀牢山北段土地利用变化研究

利用由1974,1987和2003年3期遥感影像解译的土地利用图,以哀牢山北段为研究区,借助GIS技术,并结合数理统计分析方法,分析了土地利用的动态变化特征.结果表明:1974~2003年,哀牢山北段各土地利用类型发生了显著的变化,有林地、灌木林、荒草地和耕地(主要是水田和旱地)相互之间转化比较激烈.近30年间有林地是该区域的优势地类,但这种优势正在逐渐减弱,3个时期中分别占总面积的71.67%,68.11%,64.76%.1974~1987年,旱地、灌木林、水田表现为增长,旱地增长较快,灌木林、水田增长较慢;荒草地和水体表现为减少.1987~2003年,灌木林、建设用地、荒草地、水田、水体表现为增长,灌木林、建设用地增长较快,荒草地、水田、水体增长较缓慢;旱地逐步萎缩;水浇地在整个研究时段保持较平衡状态.通过景观格局分析发现,总体上景观斑块数量不断增加,平均斑块面积却不断减少,景观破碎程度呈增加的趋势,受到人类的强烈干扰,景观多样性和均匀度持续增加,优势度不断下降,本地区土地利用朝着破碎化、多样化和均匀化的方向发展.     

地形对兰州市中心城区土地利用空间格局的影响

选择兰州市中心城区为研究区域,结合分类决策树自动提取的土地利用信息,利用DEM数据获取地形因子,定量分析兰州市各地形分级单元内的土地利用空间格局特征.结果表明:80%以上的城乡及工矿用地以及90%以上的水域分布在较低、较缓的区域,60%的林地和草地分布在较高、较陡的区域,约50%的未利用地分布在高程2 000 m、坡度15°区域内,可以考虑一定程度的开发利用;高程1 600 m,坡度5°~8°区域内,景观最为破碎,形状最不规则,生态环境最为脆弱;高程1 600~2 000 m、坡度8°~15°区域内,土地利用景观类型最为丰富;高程2 800 m的区域内,同类型土地利用景观不断集中、合并,土地利用景观的整体性最强.     

山西省土地覆被景观格局分析

基于2000年山西省1∶10万土地利用数据,在ArcView和Fragstats软件支持下,对山西省土地覆被景观格局特征进行了分析.结果表明,在区域内6大景观类型中,以耕地(39.16%)、草地(29.25%)和林地(27.90%)为主;区域景观多样性偏低(1.234),破碎度指数偏高(0.92),平均斑块形状指数偏大(2.18),说明人类活动对土地利用/覆被格局产生了深刻影响.就耕地、林地和草地3类植被景观而言,平原旱地为耕地的主导类型,分布较为连续,其它旱地面积较大,但质量较差;林地较为完整,疏林地破碎度指数(1.33)和平均斑块形状指数(2.13)较大;低覆盖度草地(48.8%)在草地中占优势.     

福清市景观空间格局特征分析

以地理信息系统和景观生态学为研究方法，以福清市为研究区域，应用FRAGSTATS软件计算研究区各景观指标，结果表明：林地、耕地是景观的背景基质，建设用地、草地、水域充当斑块功能；林地景观斑块形状最复杂，耕地、建设用地居中，水域、草地较简单；林地、水田、旱地、建设用地斑块分布较为紧凑；研究区各景观类型所占面积比例差异较大，景观多样性水平和均匀程度均较低．     

拉市海流域景观多样性空间特征分析

将GIS和统计分析相结合,以2010年土地利用类型图为基础,选取了斑块面积等8种景观指标,通过计算景观指标分析了拉市海流域景观多样性的空间分布特征.结果表明:林地作为流域内景观基质,由于人为影响其斑块形状较复杂;耕地分布均匀,聚合度连接度都较高;水域分布空间差异性明显,且多以大斑块团聚分布;草地和建筑用地分布零碎但连接度良好;未利用地集中分布于个别村.研究区内景观类型多样性随海拔升高因人类活动影响减弱而降低.     

太原市娄烦县LUCC的景观格局分析

为了促进区域土地利用向合理化、科学化的方向发展,利用1996年和2004年的数字化土地利用图,应用景观格局分析的方法,从景观多样性、优势度和景观空间结构分析了区域LUCC变化情况.结果表明,土地各景观要素破碎度变大,连通性变差;景观类型分散性加强;耕地、林地、草地等明显较少,工矿业和居民用地增加.人类活动对景观要素的干扰程度加大,导致了区域生态环境的不稳定,影响到太原市的工农业稳步发展.     

大宁河流域土地利用变化及其对景观格局的影响

研究区域土地利用变化对景观格局的影响有助于合理调控土地利用方式。以大宁河流域为研究区域,利用Arcgis9.3和Fragstats 3.3分析了大宁河1988—2010年间的土地利用变化及景观格局演变,系统分析了不同坡度、不同高程、不同岩性区的土地利用变化对流域景观格局的影响。结果表明:1)1988—2010年间大宁河土地利用变化较为显著,以旱地面积的增加和灌木林的减少及建设用地的增加为显著特点,集中体现在低高程(小于800m)、低坡度(小于25°)下的泥岩砂岩地区;2)大宁河流域景观多样性指数上升,景观格局较为破碎;3)大宁河流域土地利用变化改变了景观格局,与人类的干扰程度有关。最后,提出在不同坡度、高程及不同岩性区采用不同的土地利用方式,以降低景观格局变化带来的负面效应。     

安徽舒城县土地利用类型斑块分形特征

运用分形理论,对舒城县土地利用类型图斑的周长、斑块边缘密度和斑块形状指数的标度-频度关系进行了定量分析,结果表明:平原区、岗丘区、山区土地利用类型图斑的数目分别为514、222、94,图斑数目逐渐减少,同时景观异质性和景观破碎度逐渐降低.平原区占据优势地位的斑块是耕地,其面积占到平原区斑块总面积80%以上.岗丘区耕地和林地斑块面积百分比分别为31%和61%,占据着优势地位.山区则是林地斑块,其面积百分比为87%.斑块边缘密度普遍较高,土地利用类型斑块边缘趋向复杂化;斑块形状指数大部分小于1.5,斑块形状总体处于比较简单的状态;土地利用类型图斑的周长、斑块边缘密度和斑块形状指数的标度-频度双对数关系显著,相关系数均超过0.9,呈高度负相关,其分形关系客观存在.     

大宁河流域土地利用变化及其对景观格局的影响

研究区域土地利用变化对景观格局的影响有助于合理调控土地利用方式。以大宁河流域为研究区域,利用Arcgis9.3和Fragstats 3.3分析了大宁河1988—2010年间的土地利用变化及景观格局演变,系统分析了不同坡度、不同高程、不同岩性区的土地利用变化对流域景观格局的影响。结果表明:1)1988—2010年间大宁河土地利用变化较为显著,以旱地面积的增加和灌木林的减少及建设用地的增加为显著特点,集中体现在低高程(小于800m)、低坡度(小于25°)下的泥岩砂岩地区;2)大宁河流域景观多样性指数上升,景观格局较为破碎;3)大宁河流域土地利用变化改变了景观格局,与人类的干扰程度有关。最后,提出在不同坡度、高程及不同岩性区采用不同的土地利用方式,以降低景观格局变化带来的负面效应。     

Markedness and its Interpretation in Language Use

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.     

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.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

A computer generator for randomly layered structures

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

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.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the