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WANG Yangyang XIAO Yu XU Jie XIE Gaodi QIN Keyu LIU Jingya NIU Yingnan GAN Shuang HUANG Mengdong 《资源与生态学报(英文版)》2022,13(5):763-774
Inner Mongolia is the important ecological barrier zone in northern China, which plays an important role in the prevention and control of wind in the regional ecosystem. Based on the Revised Wind Erosion Equation (RWEQ) model and the cost-recovery method, this study simulated the wind erosion prevention service (WEPS) in Inner Mongolia in 2010 and 2015, investigated the spatial pattern of material and monetary value of WEPS, and analyzed the differences among various cities and various ecosystems. The results indicated that the total WEPS of Inner Mongolia was estimated to be 73.87×108 t in 2015, which was 4.61×108 t less than in 2010, while the monetary value of WEPS was calculated to be 738.66×108 yuan in 2015, which was 46.16×108 yuan less than in 2010. Among all the leagues and cities, Xilin Gol League supported the highest WEPS, reaching 18.65×108 t in 2015, while Wuhai provided the lowest. The WEPS of Hulunbeier increased the most, by 4.37×108 t from 2010 to 2015. The WEPS in the grassland ecosystem was the highest among the different ecosystems, accounting for more than 55% of the total WEPS in Inner Mongolia, but it was reduced by 1.05×108 t during the same period. The WEPS in the forest ecosystem increased the most, reaching 0.19×108 t. This study found that the implementation of projects such as returning farmland to forests and grasses and sand control effectively increased the WEPS by increasing the forest area. However, unsuitable land use increased the desertification of ecosystems which resulted in a reduction of WEPS in Inner Mongolia. 相似文献
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核方法广泛应用于模式识别等领域,但其存在着特征抽取效率和样本集的大小成反比的瓶颈问题.因此提出一种基于数值逼近的方法确定虚拟样本矢量,以此代替训练样本,提高KPCA(Kernel Principle Component Analysis)特征抽取效率.在确定虚拟样本矢量时,只需将样本矢量的初值设定为随机变量,算法实现简单、高效.在基准数据集上的实验结果显示该算法优于同类算法. 相似文献
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Farmland function evolution in the Huang-Huai-Hai Plain: Processes,patterns and mechanisms 总被引：6，自引：2，他引：4
Using counties as the basic analysis unit, this study established an evaluation index system for farmland function (FF) from economic, social, and ecological perspectives. The method combining entropy weighting and multiple correlation coefficient weighting was adopted to determine the weights, and the FF indices were calculated for each county. Subsequently, the spatio-temporal characteristics of farmland function evolution (FFE) were analyzed and the coupled relationships between the sub-functions were explored based on a coupling coordination model. At the same time, the dynamic mechanism of FFE was quantitatively analyzed using a spatial econometric regression analysis method. The following major conclusions were drawn: (1) The farmland economic function generally exhibited a declining trend during 1990–2010, and it is essential to point out that it was stronger in underdeveloped and agriculture-dominated counties, while it continuously weakened in developed areas. Farmland social function decreased in 60.29% of the counties, whereas some counties, which were mostly located in north of Zhengzhou and west of Dezhou and Cangzhou, Yantai, and Weihai, clearly increased. A dramatic decline in farmland ecological function occurred around Beijing, Tianjin, and Jinan. Areas located in the northern part of Henan Province and the central part of Shandong Province saw an increase in ecological function. (2) There was a significant spatial difference in the coupling degree and coordination degree of the sub-functions, and the decoupling phenomenon highlighted this. The changes in social function and ecological function lagged behind economic function in developed areas, but these were highly coupled in some underdeveloped areas. (3) FFE in the Huang-Huai-Hai Plain (HHHP) is resulted from the comprehensive effects of regional basic conditions and external driving factors. Furthermore, the transitions of population and industry under urbanization and industrialization played a decisive role in the evolution intensity and direction of farmland sub-systems, including the economy, society, and the ecology. According to the results mentioned above, promoting the transformation from traditional agriculture to modern agriculture should be regarded as an important engine driving sustainable development in the HHHP. Taking different regional characteristics of FFE into account, differentiated and diversified farmland use and management plans should be implemented from more developed urban areas to underdeveloped traditional agricultural areas. 相似文献
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Yingnan Wang Hieu T. Tran Giang D. Nguyen Pathegama G. Ranjith Ha H. Bui 《国际地质力学数值与分析法杂志》2020,44(10):1417-1445
This paper focuses on the modelling of mixed-mode fracture using the conventional smoothed particle hydrodynamics (SPH) method and a mixed-mode cohesive fracture law embedded in the particles. The combination of conventional SPH and a mixed-mode cohesive model allows capturing fracture and separation under various loading conditions efficiently. The key advantage of this framework is its capability to represent complex fracture geometries by a set of cracked SPH particles, each of which can possess its own mixed-mode cohesive fracture with arbitrary orientations. Therefore, this can naturally capture complex fracture patterns without any predefined fracture topologies. Because a characteristic length scale related to the size of the fracture process zone is incorporated in the constitutive formulation, the proposed approach is independent from the spatial discretisation of the computational domain (or mesh independent). Furthermore, the anisotropic fracture responses of materials can be naturally captured thanks to the orientation of the fracture process zone embedded at the particle level. The performance of the proposed approach demonstrates its potentials in modelling mixed-mode fracture of rocks and similar quasi-brittle materials. 相似文献
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农业绿色转型已经成为乡村振兴与农业农村深化改革的必然选择,亟待探索农区农业生产转型与其环境效应的空间分异规律与地域类型,从而推进农业的高质量发展。本文基于类型学视角采用判别法将黄淮海平原农区的农业生产类型划分为城市近郊现代集约型、城市近郊传统经营型、城市远郊现代集约型和城市远郊传统经营型。从拉力、支撑力及引导力的视角,构建以“发展主体适应-要素变化-环境响应”为主线的分析框架,解读了农业生产系统转型及其环境效应的动力机制和特征。黄淮海平原农业生产系统转型负向环境效应的形成机制为在增产增收的目标导向及区域自然条件约束下,资本、技术及劳动力的非理性投入对农业生态系统的扰动。将农业生产系统转型与环境效应的耦合类型划分为城郊现代集约高强度污染型、城郊现代集约中度污染型、城市远郊现代集约高强度污染型和城市远郊现代集约中度污染型。基于以上分析,从普适性与异质性视角提出了相应的政策启示与优化调控策略,以期实现平原农区农业生产系统的可持续健康转型。 相似文献
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正Objective Typical Early Cretaceous non-marine bivalve fossils from Eastern Asia are represented by the Arguniella-Sphaerium assemblage, and they were important members of the Jehol Biota. Historically, the genus Arguniella in western Liaoning had been mistakenly identified as the Jurassic Ferganoconcha, re-identified as Arguniella with 相似文献
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电子商务影响下的“淘宝村”乡村重构多维度分析——以湖北省十堰市郧西县下营村为例 总被引：2，自引：2，他引：0
以湖北省十堰市郧西县下营村为例,利用半结构式访谈、问卷调查并结合遥感影像解译与GIS可视化表达等方法对电子商务驱动下乡村经济、社会及空间重构进行刻画。研究表明：① 下营村由传统的农业主导转变为一、二、三产业融合发展的多元结构,并显露出生态化转向。② 社会空间趋向于就业高度非农化、治理主体多元化、公共服务健全化、生活方式现代化及交往空间虚拟化。③ 农业生产空间逐步压缩,非农生产空间逐步扩张,生产-生态复合空间增加,居住空间呈现多功能化、集约化。④ 产业基础、电商平台、物流设施、乡村精英、资源禀赋和政府支持为其转型与发展提供了初始引擎、资源支撑和外部支持。 相似文献
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基于乡村多功能理论的贫困村域演变特征与振兴路径探讨——以海南省什寒村为例 总被引：7，自引：5，他引：2
对于多数农村地区而言,贫困是制约乡村发展的重要因素,为摆脱对农业的过度依赖和单一生产功能,乡村多功能逐步进入人们的视野并日渐受到关注,在很大程度上多功能路径有助于减少贫困发生率,并提高农村社区和家庭面对生存压力的能力。论文立足于乡村振兴的时代背景,在阐释乡村多功能概念内涵的基础上,采用实地调研和半结构式访谈等方法,基于多功能视角剖析贫困村域乡村发展的演变特征及驱动因素,总结提炼其创新发展模式,在此基础上进一步探讨贫困村域乡村振兴的路径选择。结果表明：① 在内外部驱动力的作用下,海南省什寒村实现了从弱势的贫困农村向产品多样化的多功能乡村转变;② 乡村农业生产、就业与社会保障、生态保育及文化传承等多项功能的协调发展,对于提高农村社会经济发展水平、增强乡村弹性具有积极意义;③ 驱动乡村多功能演化的因素包含政策支持、市场需求、自然本底、资金技术、行为主体和文化特质等多个方面;④ 针对贫困村域乡村发展存在的制约因素,提出从宏观层面提供乡村振兴外援力、从中观层面促进乡村振兴交互力、从微观层面激发乡村振兴内生力,通过总体谋划、各个击破以实现乡村振兴。最后从多功能视角,对乡村振兴发展的困境与出路进行了探讨。 相似文献
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Rural vitalization in China: A perspective of land consolidation 总被引：4，自引：2，他引：2
Journal of Geographical Sciences - The core objective of rural vitalization is to systemically establish a coupling pattern of various rural development elements including population, land and... 相似文献
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