土地利用结构综合数值表征——以中国西部地区为例   总被引：25，自引：3，他引：25  

王秀红  何书金  罗明 《地理科学进展》2002,21(1):17-24

应用多元统计分析中的因子分析 ,以中国西部地区各县市级行政单元为例 ,阐述了土地利用结构类型之间的关系 ,主要因子在表征土地利用集约性上的物理意义 ,以及土地利用结构的综合数值表征方法。利用 GIS的空间分析技术 ,展示了因子分析综合得分值极为丰富的结构性信息 ,并分析了这些信息在宏观分类、分区中的作用。最后 ,结合土地利用率与土地利用结构的信息熵 ,探讨了综合数值方法在分析土地利用问题以及防治土地退化方面的应用。  相似文献   

Comparative Study on Methods for Computing Soil Heat Storage and Energy Balance in Arid and Semi-Arid Areas   总被引：1，自引：0，他引：1       下载免费PDF全文

LI Yuan  LIU Shuhu  WANG Shu  MIAO Yucong  CHEN Bicheng 《Acta Meteorologica Sinica》2014,28(2):308-322

Observations collected in the Badan Jaran desert hinterland and edge during 19-23 August 2009 and in the Jinta Oasis during 12-16 June 2005 are used to assess three methods for calculating the heat storage of the5-20-cm soil layer.The methods evaluated include the harmonic method,the conduction-convection method,and the temperature integral method.Soil heat storage calculated using the harmonic method provides the closest match with measured values.The conduction-convection method underestimates nighttime soil heat storage.The temperature integral method best captures fluctuations in soil heat storage on sub-diurnal timescales,but overestimates the amplitude and peak values of the diurnal cycle.The relative performance of each method varies with the underlying land surface.The land surface energy balance is evaluated using observations of soil heat flux at 5-cm depth and estimates of ground heat flux adjusted to account for soil heat storage.The energy balance closure rate increases and energy balance is improved when the ground heat flux is adjusted to account for soil heat storage.The results achieved using the harmonic and temperature integral methods are superior to those achieved using the conduction-convection method.  相似文献   

Seasonal Changes in Phytoplankton Biomass and Dominant Species in the Changjiang River Estuary and Adjacent Seas：General Trends Based on Field Survey Data 1959-2009     

YANG Shu  ;HAN Xiurong  ;ZHANG Chuansong  ;SUN Baiye  ;WANG Xiulin  ;SHI Xiaoyong 《青岛海洋大学学报(英文版)》2014,(6):926-934

The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 ktg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level （including the nutrient supply from the terrestrial runoffs） was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that dia- toms were the main phytoplankton in this area, and Skeletonerna costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends： 1） Skeletonema （mainly S. costatum） was dominant throughout the year; and 2） seasonal succession trends were Coscinodiscus （spring） →Chaetoceros （summer and autumn） → Coscinodiscus （winter）. The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas： average annual phytoplankton biomass and dinoflagellate proportion both presented inc  相似文献   

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������  ��� 《大地测量与地球动力学》2014,34(6):126-130

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基于GIS的赣州市房地产信息系统的设计与开发     

曾洁  贺书 《测绘与空间地理信息》2014,(3):107-110,113

主要研究的是赣州市房地产管理信息系统的设计和开发,利用.net开发平台和现代GIS技术,从体系结构、系统分析设计、数据库设计和与其他系统之间的数据交换等方面进行考虑,建立一个安全完善、灵活扩展的应用系统。进一步提升了赣州市房产管理的信息化和规范化水平,同时为"数字赣州"打下了坚实的数据基础。  相似文献   

基于B／S模式的测绘实验室管理系统     

王新志  沈圆圆  李亚云  李妹  张晓颖 《测绘工程》2013,(5):65-68

随着Internet技术的快速发展,越来越多的管理系统倾向于建立基于网络的管理系统。为了充分利用现有的发展成果,彻底改变测绘实验室传统的人工管理方式,更好地发挥测绘实验室在人才培养方面的基础保障作用,采用VisualStudio2008（CJHJ）作为开发工具,运用ASP．NET发布动态网页,SQLServer作为后台数据库服务器设计开发了测绘实验室管理系统,实现测绘实验室的网络化、数字化管理,提高管理效率,具有很好的推广应用价值。  相似文献   

Adsorption of Complex Pollutants from Aqueous Solutions by Nanocomposite Materials     

Yeoung‐Sheng Wang  Shu‐Huei Hsieh  Chang‐Hung Lee  Jao‐Jia Horng 《洁净——土壤、空气、水》2013,41(8):828-828

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Soil NO3− storage from oasis development in deserts: Implications for the prevention and control of groundwater pollution     

Shi Qi  Wei Liu  Heping Shu  Fei Liu  Jinzhu Ma 《水文研究》2020,34(20):3941-3954

The sources and storage of soil NO₃⁻ in the western Tengger Desert, Northwest China, were explored using water chemistry analysis and stable isotope techniques. In line with the expansion and development of oases, part of the desert has been transformed into cultivated land and artificial forest land. The mean soil NO₃⁻ contents found in areas of cultivated land and artificial forest were 123.06 mg kg⁻¹ and 1.26 mg kg⁻¹, far higher and slightly lower than the background desert soil values, respectively. The δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ values in cultivated soils ranged from 1.00 to 11.81 ‰, and from −1.85 to 8.99 ‰, respectively, and the mean mNO₃⁻/Cl⁻ value in cultivated soils was 2.3. These figures would appear to demonstrate that the rapid increase in the nitrate content in soils is principally due to the use of nitrogen fertilizer. Such increases in soil NO₃⁻ storage is likely to promote the leaching of nitrogen into the groundwater where coarsely textured soils exist, the pollution of water sources used for irrigation water, and extreme precipitation events. The δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ values in groundwater ranged from 3.72 to 6.54 ‰, and from −0.19 to 12.06 ‰, respectively, mainly reflecting the nitrification of soil nitrogen. These values appeared similar to those measured in the soil water in adjacent areas of cultivated land and vegetated desert, indicating that the groundwater has been affected by both natural and artificial NO₃⁻. Artificial afforestation of desert regions would therefore seem to be a useful way of reducing the threat posed by anthropogenic sources to the circulation of NO₃⁻-N within arid regions, as well as promoting wind sheltering and sand fixation. This study explored the NO₃⁻ storage and groundwater quality responses to oasis development in arid areas in an attempt to provide effective information for local agricultural organizations and agricultural nitrogen management models.  相似文献   

双路后备电源管理系统的设计与实现     

孙宏志  束杨  刘一萌  李秀丽  蕾晨  马千里 《地震地磁观测与研究》2010,31(Z1)

介绍一种基于GSM(全球移动通信系统)网络SMS(短信业务)的双路后备电源管理系统的原理及设计实现.它由一个无线GSM模块(WAVECOM公司的Q2403模块)和一个单片机(AT89S52)为核心的监控单元组成,监控单元利用AT指令通过串口和GSM模块进行通信.该系统借助GSM模块Q2403,使用户能够通过短信便捷地对双路后备电源进行参数设置和控制.  相似文献   

Eclogite-melt/peridotite reaction: Experimental constrains on the destruction mechanism of the North China Craton   总被引：2，自引：0，他引：2  

WANG Chao    JIN ZhenMin  GAO Shan  ZHANG JunFeng & ZHENG Shu State Key Laboratory of Geological Processes  Mineral Resources  China University of Geosciences  Wuhan  China  State Key Laboratory of Inorganic Synthesis  Preparative Chemistry  College of Chemistry  Jilin University  Changchun 《中国科学:地球科学(英文版)》2010,(6)

To study the mechanism of melt-peridotite reaction pertinent to the destruction of the North China Craton (NCC) lithosphere, a series of experiments were performed at a pressure of 2.0 GPa and temperatures from 1250 to 1400°C using Bixiling eclogite and Damaping peridotite as starting materials. The experimental results show that the reaction between eclogite melt and peridotite causes dissolution of olivine and orthopyroxene and precipitation of clinopyroxene in the melt. The experimental run products, cha...  相似文献