Impacts of land use change on landscape patterns in mountain human settlement: The case study of Hantai District(Shaanxi,China)

Mountain area is an important geographical unit of land,and its ecology is sensitive and fragile.Over the past few decades,human activities have caused dramatic changes in land use in mountainous areas,which caused changes in landscape patterns and impacts on the ecological environment.It is unknown how the mechanism of land use affects the landscape pattern at different scales.The Hantai District,a typical human settlement in the mountain area in Shaanxi,China,was chosen as the study area.Based on the remote sensing images,the mathematical models and landscape indexes were adopted to evaluate the impact of land use change from 1998 to 2017 on the landscape pattern at different scales,and its main driving forces were analyzed.The results showed that the urbanized land expanded largest from 15.39%to 24.30%,and cultivated land experienced the largest decline from 43.54%to 35.35%.Changes in land use have made the patch morphology of most land types developed from a natural random to a sawtooth shape,and its spatial pattern evolved from a ruleset to a fragmented expansion.This reflects the continuous strengthening of human intervention in the process of regional development.Under the jurisdiction of Hantai District,the biggest change in landscape pattern is in Hanzhong City and Qili Town.The improved economy and increasing population and urbanization rate were the main factors that cause these changes.This research could provide necessary information for understanding the evolution mechanism of land resources in mountainous human settlements for mountainous areas with significant geomorphic differentiation.     

房地产宏观政策期待加大执行力

4月27日,中国社会科学院城市发展与环境研究中心和社会科学文献出版社联合主办的2007年中国房地产高峰论坛暨《 房地产蓝皮书》2007年版出版发布会在北京举行.来自中国社会科学院、国土资源部、建设部、国家统计局、中国房地产协会等部门的专家、学者和官员出席了会议.     

边城廿八都

浙西南的江山市廿八都镇,地处浙闽赣三省交界。四面群山拱卫,仙霞古道穿镇而过,自古有“东南锁钥,入闽咽喉”之称。小镇类似文学家沈从文笔下的边城,当时“也有商人落脚的客店,坐镇不动的理发馆。此外,饭店、杂货铺、油行、盐栈、花衣庄,莫不各有一种地位,装点这条小河街。”而唐宋古道驿站遗址和明清古桥民居至今尚存。     

"一户一宅"的思考

《土地管理法》第六十二条规定,农村村民一户只能拥有一处宅基地。这对于节约集约用地,强化农村宅基地管理具有十分重要的指导意义。长期以来,农村旧的宅基地管理模式造成农村村民住房严重超标,一户多宅以及空心村的现象普遍存在,农村宅基地极度浪费。“一户一宅”制从当前全国农村的实际出发,对农村宅基地使用作出了科学合理的界定。但是,在执行“一户一宅”过程中,也出现一些新情况新问题,在市场经济条件下,这些新情况新问题必须在立法和实践中加以解决,并不断完善现有的制度,以达到科学合理地利用农村土地。     

Influence of the roots of mixed-planting species on the shear strength of saline loess soil

In order to improve our knowledge of the mechanical effect of the roots of mixed-plantings on soil reinforcement and slope protection,the influence of roots of a mixed-planting with four herb species(Medicago sativa L.,Elymus nutans Griseb.,Puccinellia distanx(L.),and Poa pratensis L.)and one shrub species(Caragana korshinskii Kom.)were investigated on the shear strength characteristics of saline loess soil.The root distribution characteristics were assessed via a survey when the plants grew for one year.The effects of the root biomass density,the root mass ratio(RMR)of the fine roots to the coarse roots,the moisture content,and the salt content on the shear strength index of the rooted soil were analyzed via a triaxial compression test,and the mechanism of these effects was discussed.The results indicate that the biomass density decreased linearly with increasing depth.The RMR initially decreased with depth and then increased,exhibiting in a quadratic relationship.The cohesion of the rooted soil increased linearly as the biomass density increased.The cohesion of the rooted soil initially increased with increasing RMR and salt content,and then it decreased.The turning point of the cohesion occurred when the RMR was 0.6 and the salt content was 1.18%.The internal friction angle of the rooted soil initially increased with biomass density and then decreased,and the turning point of the internal friction angle occurred when the biomass density was 0.015 g/cm3.The relationships between the internal friction angle of the rooted soil and the RMR and salt content were exponential incremental and linear subtractive relationship,respectively.Both the cohesion and the internal friction angle of the rooted soil linearly decreased with increasing moisture content.     

Combined Bearing Capacity of Spudcans on a Double Layer Deposit of Strong-Over-Weak Clays

An extreme sea storm process can lead to a jack-up rig under the combined loading condition of vertical load(V), horizontal load(H), and moment(M) to have stability problems. This paper presents the analysis of combined bearing capacities of a circular spudcan on layered clays with a strong layer overlying a comparatively weaker layer. Numerical models combined with displacement-based load tests, swipe tests, and constant ratio displacement probe tests are adopted to calculate the uniaxial bearing capacities, failure envelopes in combined V-H, V-M planes, and failure envelopes in a combined V-H-M load space, respectively. A parametric study on the effects of vertical load level V, the layer strength ratio s_u,t/s_u,b, and the hard layer thickness t_1 on the bearing capacities is then performed. Results show that the vertical load level is a key factor that influences the values of H and M and the size of the H-M failure envelope. The existence of the underlying weak clay decreases the bearing capacities in all directions, and the vertical capacity Vult is affected more than the horizontal(H_ult) and moment(M_ult) capacities based on a single uniform deposit. The influence of the underlying weak clay on H-M failure envelope is mainly shown where H and M are coupled in the same direction. In contrast, little difference is observed when H and M are coupled in opposite directions.     

Characteristics and dynamics of the Ganqiuchi rock avalanche triggered by a paleo-earthquake in the Northern Qinling Mountains

Analyzing large prehistoric rock avalanches provides significant data for evaluating the disaster posed by these relatively infrequent but destructive geological events. This paper attempts to study the characteristics and dynamics of the Ganqiuchi granitic rock avalanche, in the middle of the northern margin of Qinling Mountains, 30 km to the south of Xi’an, Shaanxi Province, China. In plane view, this rock avalanche is characterized by source area, accumulation area and dammed lake area. Based on previous studies, historical records and regional geological data, the major trigger of the Ganqiuchi rock avalanche is considered to be a strong paleo-earthquake with tremendous energy. The in situ deposit block size distributions of the intact rock mass and the debris deposits are presented and analyzed by using a simple model for estimating the number of fragmentation cycles that the blocks underwent. The results show that the primary controlling factor of the fragmentation process is the pre-existing fractures, and there is a relationship between the potential energy and the fragmentation energy: the latter is approximately 20% of the former. Based on the dynamic discrete element technique, the study proposes a four-stage model for the dynamic course of the Ganqiuchi rock avalanche:(1) failing;(2) highspeed sliding;(3) collision with obstacles;(4) decelerated sliding, which has implication for hazard assessment of the potential rock avalanches in China and other countries with similar geological setting.     

Oxidation Modification of Polyacrylonitrile-Based Carbon Fiber and Its Electro-Chemical Performance as Marine Electrode for Electric Field Test

A novel sensor for ocean electric field testing has been fabricated by polyacrylonitrile-based on carbon fibers with electro-chemical oxidation.The surface profile characteristics of the carbon fibers were characterized by scanning electron microscope,Fourier transform infrared spectra and contact angle.Cyclic voltammetry and Tafel curves have been used to study its electro-chemical performances.Two identical electrodes in sea water as the electric field sensor will swiftly respond to applied electric field which causes positive and negative ions to move in opposite direction,resulting in a electric potential difference(ΔE).Test result indicates that the offset potential is typically below 1 m V with a drift of 60-170μVd^-1.Typical self noise level is 1.07 nV√Hz^1/2@1 Hz.The electric field response indicates that the modified electrode pair shows better response to AC sine signal of amplitude and frequency(5 mV and 1 mHz)respectively than its blank.The electric field response model of the modified electrodes is creatively presented according to its electric double layer capacitance and Faraday pseudo-capacitance.Many advantages of the carbon fiber electric field electrode will make it have potential application prospect.     

Effect of Carbonation and Drying-Wetting Cycles on Chloride Diffusion Behavior of Coral Aggregate Seawater Concrete

Based on seawater immersion,drying-wetting cycles,carbonation and drying-wetting cycles for coral aggregate sea-water concrete(CASC)with different strength grades,the effect of carbonation and drying-wetting cycles on chloride diffusion be-havior of CASC is studied.The results show that the free surface chloride concentration(Cs),free chloride diffusion coefficient(Df)and time-dependent index(m)of CASC in the drying-wetting cycles is obviously higher than that in seawater immersion.The Df and m of CASC of carbonation and drying-wetting cycles is higher than that in the drying-wetting cycles.Carbonation increases the Df and m of CASC,which is against CASC to resist chloride corrosion.The corrosion possibility of CASC structures in different ex-posed areas is as follows:splash zone(carbonation and drying-wetting cycles)>tidal zone(drying-wetting cycles)>underwater zone(seawater immersion).Besides,the chloride diffusion rate of C65-CASC is 17.8%-63.4%higher than that of C65-ordinary aggre-gate concrete(OAC)in seawater immersion(underwater zone).Therefore,anti-corrosion measures should be adopted to improve the service life of CASC structure in the oceanic environment.     

湘西自治州贯彻执行《土地管理法》调查报告

为推进湘西自治州贯彻执行《中华人民共和国土地管理法》(以下简称《土地管理法》)工作的健康发展,州政协委员视察组一行13人,对《土地管理法》颁布实施以来全州8     

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

介绍GPS定位中的几个概念

文章概略介绍了利用卫星进行定位的原理 ;由卫星信号传播、信号接收和SA政策等引起的理论误差 ;给出了多种快速、高精度定位的工作模式和观测点选择的原则 ;列出了将WGS - 84坐标转换为我国坐标的公式及解算参数的具体方法 ,供读者在GPS工作中参考。     

Influence of livestock soil eutrophication on floral composition in the Pyrenees mountains

Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were （i） to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and （ii） to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients （nitrate,ammonium,phosphorus,potassium,calcium and magnesium）,total nitrogen,organic carbon and pH were measured.
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien     

浙江长兴顾渚山优质紫笋茶与地质背景相关性分析

长兴水口顾渚山风景区的紫笋茶,是闻名国内外的优质名茶。本文在实地调查的基础上,分析了紫笋茶优异的品质与地质环境背景条件的相关性。特定的地质背景条件,首先造就了一个避风向阳、雨量充沛的小气候环境;特定的泥盆系与花岗岩类浸入岩的地层背景所形成的土壤,为茶树生长提供了大量的营养物质,特别是有益的微量元素对提高茶叶品质起到了重要作用;同时这一特定的背景条件下,形成了对茶树生长有利的酸性土壤。特定的水文地质背景条件．又提供了充足的水份,还补充了茶树生长所必需的营养物质。通过对环境背景条件的分析,最终提出了长兴县茶叶发展的方向。     

Sea ice thickness measurement in spring season in Bothnian Bay using an electromagnetic induction instrument

As an important component of the cryosphere,sea ice is very sensitive to the climate change.The study of the sea ice physics needs accurate sea ice thickness.This paper presents an electromagnetic-induction(EM) technique which can be used to measure the sea ice thickness distribution efficiently,and the successful application in Bothnian Bay.Based on the electromagnetic field theory and the electrical properties of sea ice and seawater,EM technique can detect the distance between the instrument and the ice/water interface accurately,than the sea ice thickness is obtained.Contrastive analysis of the apparent conductivity data obtained by EM and the value of drill-hole at same positions allows a construction of a transformable formula of the apparent conductivity to sea ice thickness.The verification of the sea ice thickness calculated by this formula indicates that EM technique is able to get reliable sea ice thickness with average relative error of only 12%.The statistic of all ice thickness profiles shows that the level ice distribution in Bothnian Bay was 0.4-0.6 m.     

韩山蓝晶石矿床成因研究

通过对韩山蓝晶石的性质、分布、物质来源等因素的分析,结合晶体主长理论,推测其是经过区域变质作用形成第一世代蓝晶石,侧分泌作用形成第二世代蓝晶石。     

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网络聊天监控系统的研究和实现

Internet给人们提供了越来越方便的信息交流方式。由于Internet的虚拟化，人们对网络空间法律意识的淡薄，以及Internet提供的服务功能的安全和监管问题，也日渐突出。分析了Internet提供的网络聊天服务功能的现状和存在的问题，在此基础上，提出了一套较为完善的网络聊天监控与安全管理的解决方案，并实现了对用户进行网络聊天内容的监控管理应用。     

试论企业实行加速折旧

当前许多生产企业的生产设备已非常陈旧 ,然而这些企业却不愿更新 ,原因之一就是因为在大多数企业只被允许采用直线法等一般的折旧方法对固定资产进行计提折旧 ,使得企业在固定资产方面的投资收回较慢 ,大大限制了企业在固定资产方面投资的积极性。针对这一现状 ,文章从“实行加速折旧不会减少国家财政收入”入手 ,论述了实行加速折旧的可行性 ,从 3个方面论述了实行加速折旧的必要性。认为扩大加速折旧企业的范围已切实可行。     

State and Development： Changes in Livelihood Strategies in Garhwal with Special Reference to Ecotourism in the Gangotri Region

The object of the paper is to provide an insight into the changes in livelihood strategies of the people in the Garhwal Himalayas over time. From sustaining an economy based on transit trade and subsistence agriculture, there has been a shift towards tourism in recent times. This shift has been due to the tradition of pilgrimage to the higher reaches and also due to promotion by the state by developing infrastructure and providing incentives. The paper is divided into four parts. In the first part, the policies of the colonial state and the events leading to the destruction of forests and the impoverishment of the self-sustaining semi-pastoral economy in the Garhwal Himalayas are outlined. It is argued that the destruction of forests and subsequently, the economy of the Himalayas were directly responsible for the large-scale migration to the plains. This also led to further exploitation of forests by the people who were unfamiliar with any other form of livelihood. The paper also discusses the policies of the newly independent Indian state and sees them as an extension of the British policy of large-scale exploitation of Himalayan forests for the purpose of development and economic growth. In the third section, the growth of ecotourism as a direct outcome of the orocess of deforestation and as resulting from the need of society to conserve and yet to earn a livelihood is discussed. The case study of the Gangotrir egion examines the dilemma faced by the people of Garhwal in sustaining their livelihood, income or the development in the area. In addition, tourism has fostered monopolies of groups external to the region thereby contributing neither to the income or the development in the area. In addition, there is an added threat to the environment-deforestation, and erosion-a direct outcome of increased and unplanned tourism. Such problems demand state intervention and management of t.ourism. The conclusion to the paper asserts that in order that the requirements of the society to progress and to sustain itself in its natural habitat are not compromised, it is essential to increase the process of democratization by strengthening local structures and by vesting the community with the autonomy to determine its future. The paper therefore argues that ecotourism in the Himalayas undertaken without local involvement is not desirable. The constant need for local monitoring of external agencies or even of the State‘s participation and the need for re-evaluation of environmental standards are cumbersome details that add to the costs of promoting low-impact tourism. To be viable, ecotourism should be community based and the needs of the community, their ideas of conservation should be given prime importance and local community must be encouraged to review the standards governing conservation. Local structures should thus receive patronage and promotion, so that ecotourism becomes a dynamic facet of economic development.