检索结果-南通市图书馆

Forestry Studies in China 2009年第2期11卷 85-92页

作者： Hemmavanh CHANHDA wu ci-fang Yoshida AYUMI Department of Land Resource Management Zhejiang University Hangzhou 310029 P. R. China Zhejiang University Tea Research Institute Hangzhou 310029 P. R. China

Forest cover and land use change directly impact biological diversity worldwide, contribute to climate change and affect the ability of biological systems to support human needs by altering ecosystem services. Given the forest land use characteristics and ecosystem types in Luang Namtha Province, Lao PDR, the forest cover and land cover category of Luang Namtha Province were divided into six classes, i.e., current forest （CF）, potential forest （PF）, other wooded areas （OW）, permanent agricultural land （PA）, other non-forest areas （NF） and water （W）. In first instance, earlier geographic information data （GIS data） of forest cover and land use during 1992 and 2002 was obtained from the Ministry of Agriculture and Forestry （MAF）, Lao PDR. Two steps of forest land use change assessment were conducted by the MAF, i.e., plot sampling on satellite image maps （SIMs） to detect the changes of forest cover and land use during 1992 and 2002 for the entire Luang Namtha Province and field verification in order to identify causes of the changes. Secondly, dynamic information of the forest land cover changes during this ten-year period was calculated by means of map algebra in ArcGIS 9.2. Thirdly, based on the theory of ecosystem service functions and the service function values of different global ecosystems, the value of the six forest cover and land use categories in the province was obtained. Finally, ecological environmental effects, produced by the regional land cover changes over the study period, were calculated.

关键词： ecosystem services forest land use Luang Namtha Lao PDR

Quantification of the effects of management factors on maize (Zea mays L.) and cotton(Gossypium hirsutum L.) residues decomposition rate

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Journal of Environmental Sciences 2002年第2期14卷 165-172页

作者： JONES Chilima, HUANG Chang yong, wu ci fang (College of Natural Resources and Environment, Zhejiang University, Hangzhou 310029, China.

Efforts to quantify management effects on decomposition rate of added substrates to the soil is important especially where such information is to be used for prediction in mathematical or simulation models. Using data from a short term (60 days) greenhouse simulation study, a procedure for quantifying effects of management on SOM and substrate decomposition is presented. Using microbial growth rate u (q), microbial efficiency in substrate utilization e (q), specific decomposition rates for added plant residues to two contrasting soils, red earth (Ferrasol) and black earth (Acrisol) were estimated. The treatments included straw addition + buried, (T1); straw addition + mineral N (T2); and straw addition + tillage, (T3). Sampling was done every 15 days. Straw decomposition rate was affected by external mineral N sources (Urea 46% N). Addition of an external N source significantly increased decomposition rates. The study could not, however, fully account for the effect of tillage on residues because of the limited effect of the tillage method due to the artificial barrier to mechanical interference supplied by the mesh bags. It is concluded that using few decomposer parameters, decomposition rates and consequently SOM trends in a soil system can be monitored and quantification of the influence of perturbations on decomposition rate of added substrates possible.

关键词： management factors residue decomposition rate maize cotton red soil black soil

Improved Prediction and Reduction of Sampling Density for Soil Salinity by Different Geostatistical Methods

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Agricultural Sciences in China 2007年第7期6卷 832-841页

作者： LI Yan SHI Zhou wu ci-fang LI Hong-yi LI Feng Institute of Land Science and Property Management College of Southeast Land Management Zhejiang University Hangzhou 310029 P. R. China Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource Sciencea Zhejiang University Hangzhou 310029 P.R. China Department of Environmental Engineering Zhejiang University Hangzhou 310029 P.R. China

The spatial estimation for soil properties was improved and sampling intensities also decreased in terms of incorporated auxiliary data. In this study, kriging and two interpolation methods were proven well to estimate auxiliary variables： cokriging and regression-kriging, and using the salinity data from the first two stages as auxiliary variables, the methods both improved the interpolation of soil salinity in coastal saline land. The prediction accuracy of the three methods was observed under different sampling density of the target variable by comparison with another group of 80 validation sample points, from which the root-mean-square error （RMSE） and correlation coefficient （r） between the predicted and measured values were calculated. The results showed, with the help of auxiliary data, whatever the sample size of the target variable may be, cokriging and regression-kriging performed better than ordinary kriging. Moreover, regression-kriging produced on average more accurate predictions than cokriging. Compared with the kriging results, cokriging improved the estimations by reducing RMSE from 23.3 to 29% and increasing r from 16.6 to 25.5%, regression-kriging improved the estimations by reducing RMSE from 25 to 41.5% and increasing r from 16.8 to 27.2%. Therefore, regression-kriging shows promise for improved prediction for soil salinity and reduction of soil sampling intensity considerably while maintaining high prediction accuracy. Moreover, in regression-kriging, the regression model can have any form, such as generalized linear models, non-linear models or tree-based models, which provide a possibility to include more ancillary variables.

关键词： auxiliary data prediction precision sampling density soil salinity kriging

Optimised Spatial Sampling Scheme for Soil Electriclal Conductivity Based on Variance Quad-Tree (VQT) Method

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Agricultural Sciences in China 2007年第12期6卷 1463-1471页

作者： LI Yan SHI Zhou wu ci-fang LI Feng LI Hong-yi Institute of Land Science and Property Management College of Southeast Land Management Zhejiang University Hangzhou 310029 P.R.China Institute of Agricultural Remote Sensing and Information Technology Application College of Environmental and Resource Sciences Zhejiang University Hangzhou 310029 P.R.China Department of Environmental Engineering Zhe.iiang University Hangzhou 310029 P.R.China

The acquisition of precise soil data representative of the entire survey area, is a critical issue for many treatments such as irrigation or fertilization in precision agriculture. The aim of this study was to investigate the spatial variability of soil bulk electrical conductivity （ECb） in a coastal saline field and design an optimized spatial sampling scheme of ECb based on a sampling design algorithm, the variance quad-tree （VQT） method. Soil ECb data were collected from the field at 20 m interval in a regular grid scheme. The smooth contour map of the whole field was obtained by ordinary kriging interpolation, VQT algorithm was then used to split the smooth contour map into strata of different number desired, the sampling locations can be selected within each stratum in subsequent sampling. The result indicated that the probability of choosing representative sampling sites was increased significantly by using VQT method with the sampling number being greatly reduced compared to grid sampling design while retaining the same prediction accuracy. The advantage of the VQT method is that this scheme samples sparsely in fields where the spatial variability is relatively uniform and more intensive where the variability is large. Thus the sampling efficiency can be improved, hence facilitate an assessment methodology that can be applied in a rapid, practical and cost-effective manner.

关键词： variance quad-tree (VQT) sampling scheme spatial variability kriging interpolation precision agriculture

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土地科学学科建设若干基本问题的反思与探讨

中国土地科学 2014年第2期28卷 22-28页

作者：吴次芳浙江大学公共管理学院浙江杭州310029

研究目的:探讨土地科学学科建设的基本理论问题,促进学科的成熟和完善。研究方法:比较研究法和理论分析法。研究结果:土地科学的学科成熟度依然较低,主要原因一是缺乏内在一致的理论体系和学科范式,对相关学科具有高度依赖性;二是研究... 详细信息

研究目的:探讨土地科学学科建设的基本理论问题,促进学科的成熟和完善。研究方法:比较研究法和理论分析法。研究结果:土地科学的学科成熟度依然较低,主要原因一是缺乏内在一致的理论体系和学科范式,对相关学科具有高度依赖性;二是研究对象的分散和研究深度的丧失;三是过于偏重行业应用而学术性不足。土地科学研究内容的过度宽泛影响学科的成长;水利科学围绕工程范畴推进学科建设和发展的路径及经验,值得学习和借鉴。研究结论:(1)土地利用作为土地科学的"起始范畴",符合学科逻辑起点的4方面规定性;(2)土地学科的名称可确定为:土地科学与工程,其核心内容主要包括土地形成与演化、结构与功能、利用与控制、改造与建设及其相互关系,可以用一个简单的4角锥体模型来表示;(3)土地科学与工程的学科体系可以分为土地科学、土地整治工程、土地测控工程、土地规划与利用4个二级学科;(4)土地科学与工程学科的方法论可以表述为:空间分析+共轭论+追溯学+实证主义;(5)土地科学与工程学科的基本范畴可以围绕土地结构与功能、土地过程与控制、土地承载性与持续性3大板块开展学科的理论框架建构。

关键词：土地管理土地科学土地工程学科内涵学科体系研究方法论

Development of land valuation approach based on hedonic model--A case study of Vientiane capital city Laos

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Chinese Business Review 2010年第4期9卷 27-36,62页

作者： Chanhda Hemmavanh YE Yan-mei wu ci-fang Ayumi Yoshida Department of Land Resource Management Zhejiang University Hangzhou 310029 China Tea Research Institute Zhejiang University Hangzhou 310029 China Lao Government Secretary Board Office Prime Minister Office Vientiane Laos

The aim of this study is to identify the variables affecting land value. Examined land was selected from the village in Vientiane capital city Laos. Data was collected from 100 villages in center of Vientiane capital city by using survey methods. A hedonic price analysis was conducted to determine the marginal return to different land characteristics using an econometric model corrected for correlation. Parcel characteristics such as distance to public park, village income, distance of population, number of the school within 500 meters buffer, distance to the temple, distance to the major market and distance to the business center （CBD）. Arc GIS 9.2 was applied to calculate the distance of the factors, after that SPSS 15.0 was used to calculate the land price characteristic based on hedonic price model. The results showed that the distance to the center of population was the main factor influencing to the land price, and followed by school and village income. Map of the land price before and after hedonic price analysis were produced. The land price valuation approaches based on hedonic price model for Vientiane capital city were developed and land price map were predicted. Hedonic price model and GIS were very useful for this research, and finally the policy of the land valuation based on GIS was developed.

关键词： land price hedonic price model Vientiane Laos

杭州经济技术开发区失地农民生活质量指数评价及影响因素研究

维普期刊数据库评论

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中国土地科学 2009年第4期23卷 70-75页

作者：吴丽吴次芳浙江大学东南土地管理学院浙江杭州310029

研究目的:对杭州经济技术开发区内失地农民的生活质量情况进行评价并分析其影响因素。研究方法:文献资料法、抽样调查法、AHP及统计分析方法。研究结果:(1)开发区内的失地农民具有相对高的生活质量水平;(2)失地农民生活质量水平的高低... 详细信息

研究目的:对杭州经济技术开发区内失地农民的生活质量情况进行评价并分析其影响因素。研究方法:文献资料法、抽样调查法、AHP及统计分析方法。研究结果:(1)开发区内的失地农民具有相对高的生活质量水平;(2)失地农民生活质量水平的高低受到社会经济发展水平、征地年份、失地农民的个体婚姻状况、职业状况、性别、年龄等因素的影响。研究结论:失地农民生活质量问题是土地征收中的重要内容之一,本研究可为土地征收中相关的失地农民安置问题提供政策参考。

关键词：土地管理生活质量指数评价及影响因素失地农民

沿海经济快速发展地区耕地保护策略研究——以浙江省平湖市为例

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浙江大学学报（农业与生命科学版） 2006年第1期32卷 88-91页

作者：方斌吴次芳浙江大学东南土地管理学院浙江杭州310029

从平湖市的经济快速增长与耕地资源短缺一对现实矛盾出发,分析了目前经济快速发展地区耕地保护的难点,并提出了耕地保护的长期发展策略和近期对策.

关键词：经济发展耕地保护长期策略近期对策

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城市化进程中的土地自然资本利用动态分析

自然资源学报 2018年第1期33卷 1-13页

作者：方恺吴次芳董亮浙江大学公共管理学院中国杭州310058 荷兰莱顿大学环境科学研究所日本国立环境研究所

论文聚焦城市化进程中的土地自然资本利用演变,从生产性视角定义了土地足迹和土地承载力的核算方法,在此基础上运用一个区分自然资本流量与存量、可以进行"产品—地类—区域"尺度转换的三维足迹模型,对2000—2014年贵阳市的土地自然资... 详细信息

论文聚焦城市化进程中的土地自然资本利用演变,从生产性视角定义了土地足迹和土地承载力的核算方法,在此基础上运用一个区分自然资本流量与存量、可以进行"产品—地类—区域"尺度转换的三维足迹模型,对2000—2014年贵阳市的土地自然资本利用状况进行了系统分析。结果表明:过去15 a贵阳市的土地自然资本流动性提高了39.4%,存量消耗强度降低了15.7%。耕地自然资本的流量占用规模和存量消耗强度均为最大,农业生产结构逐渐由粮食主导型向蔬果主导型转变;林地取代草地成为自然资本利用第二大地类,其生态盈余是区域自然资本流量增加的主要来源;草地自然资本的存量-流量利用比虽有大幅回落,但仍存在较大的反弹风险;建设地对自然资本流量的占用规模超越草地仅次于林地,并与城市化率在1%的水平上显著正相关;水域的自然资本利用占比最小,且由以存量消耗为主过渡到以流量占用为主。论文从区域和地类两个层面揭示了城乡土地利用变化与自然资本流量占用和存量消耗之间的关系,为提升足迹核算与分析方法的科学性和标准化提供了参考依据。

关键词：自然资本城市化土地足迹三维模型贵阳市

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注入式混合型有源滤波器研究(英文)

电力自动化设备 2007年第12期27卷 21-27页

作者：汤赐罗安李建奇吴芳慈湖南大学电气与信息工程学院湖南长沙410082

提供了一种大容量、低成本的注入式混合型有源滤波器以适用于高压系统同时进行谐波抑制和无功补偿,其中,利用大容量无源滤波器实现谐波抑制和无功补偿;采用有源滤波器改善系统滤波效果并阻尼无源滤波器与系统阻抗之间的串、并联谐振。... 详细信息

提供了一种大容量、低成本的注入式混合型有源滤波器以适用于高压系统同时进行谐波抑制和无功补偿,其中,利用大容量无源滤波器实现谐波抑制和无功补偿;采用有源滤波器改善系统滤波效果并阻尼无源滤波器与系统阻抗之间的串、并联谐振。讨论了采用检测电网电流的控制策略时,注入式混合型有源滤波器的工作原理,其基本思想是通过对有源部分进行适当控制来等效增大电网支路的谐波阻抗。从抑制电网阻抗与无源滤波器之间的串、并联谐振,改善无源滤波器的滤波效果以及提高整个系统的鲁棒性3个方面详尽分析了注入式混合型有源滤波器的稳态补偿特性。相关仿真结果及工程应用效果均证明了该混合型有源滤波器对于同时进行谐波抑制和无功补偿的可行性。

关键词：谐波抑制无功补偿有源滤波器无源滤波器