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24篇 您的检索式:作者名="Jiuchun Yang"
    题名 作者 年代 出处 被引量
1Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China显示文摘As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.YANG Jiuchun ZHANG Shuwen LI Ying BU Kun ZHANG Yubo CHANG Liping ZHANG Yangzhen 2010Chinese Geographical Science2010,20,2:17
2Gully Erosion Regionalization of Black Soil Area in Northeastern China显示文摘Gully erosion is the frequent and main form of soil erosion in the black soil area of the northeastern China, which is one of the most important commodity grain production bases in China. It is encroaching upon the fertile farmland there. Regionalization of gully erosion can reveal the spatial distribution and regularity of the development of gully erosion. Based on the eco-geographical regional background features of the black soil area, this study combined the regionalization with influencing factors of the development of gully erosion. GIS spatial analysis, geostatistical analysis, spatial statistics, reclassification, debris polygon processing and map algebra methods were employed. As a result, the black soil area was divided into 12 subregions. The field survey data on type, length, volume and other characteristics indicators of gully erosion were used to calibrate the results. Then the features of every subregion, such as where the gully erosion is, how serious it is, and why it happens and develops, were expounded. The result is not only an essential prerequisite for gully erosion surveys and monitoring, but also an important basis for gully erosion prevention.YANG Jiuchun ZHANG Shuwen CHANG Liping LI Fei LI Tianqi GAO Yan 2017Chinese Geographical Science2017,27,1:13
3Cropland redistribution to marginal lands undermines environmental sustainability显示文摘Cropland redistribution to marginal land has been reported worldwide;however,the resulting impacts on environmental sustainability have not been investigated sufficiently.Here we investigated the environmental impacts of cropland redistribution in China.As a result of urbanization-induced loss of high-quality croplands in south China(~8.5 t ha^(-1)),croplands expanded to marginal lands in northeast(~4.5 t ha^(-1)) and northwest China(~2.9 t ha^(-1)) during 1990-2015 to pursue food security.However,the reclamation in these low-yield and ecologically vulnerable zones considerably undermined local environmental sustainability,for example increasing wind erosion(+3.47%),irrigation water consumption(+34.42%),fertilizer use(+20.02%) and decreasing natural habitats(-3.11%).Forecasts show that further reclamation in marginal lands per current policies would exacerbate environmental costs by 2050.The future cropland security risk will be remarkably intensified because of the conflict between food production and environmental sustainability.Our research suggests that globally emerging reclamation of marginal lands should be restricted and crop yield boost should be encouraged for both food security and environmental benefits.Wenhui Kuang Jiyuan Liu Hanqin Tian Hao Shi Jinwei Dong Changqing Song Xiaoyong Li Guoming Du Yali Hou Dengsheng Lu Wenfeng Chi Tao Pan Shuwen Zhang Rafiq Hamdi Zherui Yin Huimin Yan Changzhen Yan Shixin Wu Rendong Li Jiuchun Yang Yinyin Dou Wenbin Wu Liqiao Liang Bao Xiang Shiqi Yang 2022National Science Review2022,9,1:13
4Remote Sensing Monitoring of Gullies on a Regional Scale: A Case Study of Kebai Region in Heilongjiang Province, China显示文摘Gully erosion is one of the major causes of land degradation in most areas and attracts increasing attention from researchers. We monitored gullies in the Kebai region in Heilongjiang Province of China by using remote sensing data and found that gully density increased with the increase in slope when the slope was less than 3°. Gully density in sunny slopes or windward slopes was greater than in shady slopes or leeward slopes because of the impacts of freezing and thawing, wind and solar radiation. Specifically, the gully density in northeast slope was the greatest and in southwest was the smallest. Gully density was reduced with increasing slope length and the longer the slope length, the less the gully density changed between 1965 and 2005. Affected by runoff, gullies most easily to occur in concave slopes and the critical elevation for gully erosion was 250–275 m. Moreover, hilly regions had the greatest gully density, followed by tableland regions, whereas the gully density in flatlands was the lowest. However, the gully density of these three types of landforms all increased between 1945 and 2000, and the portion of increase was 57.45%(hill), 52.91%(mesa) and 25.32%(plain), respectively.ZHANG Shuwen LI Fei LI Tianqi YANG Jiuchun BU Kun CHANG Liping WANG Wenjuan YAN Yechao 2015Chinese Geographical Science2015,25,5:10
5A review of historical reconstruction methods of land use/land cover显示文摘理解长期的人环境的相互作用要求过去的陆地使用和陆地封面变化的历史的重建。大多数重建从历史的来源首先基于一致地可得到、相对标准化的信息。基于可得到的数据来源和回顾的研究,在我们考察的这篇论文数字重建和分析的途径和方法他们在下列方面的优点和可能的限制:(1 ) 历史的文件关于过去的陆地使用包含质或半量的信息,它通常也包括档案的文件的陆地封面数据,而是准备是很费时间的。(2 ) 历史的地图和图画为视觉、空间的量的陆地封面提供信息。(3 ) 自然档案为经过植被重建作为一个方法有重要优点并且当历史的记录失踪或缺乏时,特别有它的唯一的可能性,但是它有重建某些陆地封面类型的大限制。(4 ) 历史的重建模型逐渐地从实验模型被开发了到机械学的。方法做不仅重建在历史的时期的陆地使用 / 盖住的数量,但是它也复制空间分发。然而仍然有有高空间的分辨率的很少历史的陆地封面数据集。(5 ) 重建方法能从多重观点基于多重来源的数据和多学科的研究造历史的陆地封面,补充失踪的数据,验证重建结果并且因此改进重建精确性。然而,有挑战,仍然在探索阶段做方法。这个方法能是为历史的陆地封面重建的一个长期的发展目标。研究人员们应该集中于由开发新模型与高空间的分辨率重建历史的陆地封面数据集以便学习结果能有效地在气候、生态的效果的模拟被使用。YANG Yuanyuan ZHANG Shuwen YANG Jiuchun CHANG Liping BU Kun XING Xiaoshi 2014Journal of Geographical Sciences2014,24,4:9
6Assessment of High-standard Farmland Construction Effectiveness in Liaoning Province During 2011–2015显示文摘At present, the large-scale construction of high-standard farmland in China has improved the quality of cropland and crop production and enhanced the eco-environmental security. To obtain a comprehensive understanding of high-standard farmland construction in Liaoning Province of China during the 12 th five-year period(2011–2015), through on-the-spot investigations and remote sensing monitoring, this study assessed the construction effectiveness of ten typical sampling projects in Liaoning Province and then presented practical suggestions. The main conclusions were as follows. 1) The ranges of increase in productivity of the ten sampling projects in Liaoning Province all surpassed the goal of 1500 kg/ha. 2) Among all sampling project areas, the levels of productivity stability of nine sampling projects were higher than that of the surrounding farmland in a severe drought year. However, the productivity stability of the high-standard farmland construction project in Faku County, Yiniupu Town, declined by 1.04% compared with the surrounding farmland. 3) Except for the high-standard farmland construction project in Dengta City, Dengta Irrigation Region, the productivity uniformity of the other nine sampling projects increased by 3.30%–88.10%. 4) Eight of the ten sampling projects belonged to Class 1, and two projects belonged to Class 2, showing that the effectiveness of high-standard farmland construction in Liaoning Province was quite good.There were some suggestions for high-standard farmland construction in the future. All departments should strengthen cooperation and formulate corresponding protection and development strategies suitable for local conditions. Additionally, lasting management mechanisms should also be established. Using remote sensing monitoring to assess the high-standard farmland construction effectiveness during the 12 th five-year period could provide experience and decision-making support for high-standard farmland construction in the future.PU Luoman ZHANG Shuwen YANG Jiuchun YAN Fengqin CHANG Liping 2019Chinese Geographical Science2019,29,4:4
7Spatio-temporal Pattern and Spatial Heterogeneity of Ecotones Based oh Land Use Types of Southeastern Da Hinggan Mountains in China显示文摘Ecotones have received great attention due to its critical function in energy flux, species harbor, global carbon sequestration, and land-atmosphere interaction. This study investigated land use pattern and spatial heterogeneity of the ecotones among agricultural land, forest land, and grassland of the southeastern Da Hinggan Mountains in the northeastern China. The change of these delineated ecotones under different slopes and aridity conditions was analyzed by two landscape indices, edge density(ED) and core area percentage of landscape(CPL), to explore the inter-linkage between spatial structure of ecotones and socioeconomic development and land management. Specifically, the ecotones such as agriculture-forest(AF) ecotone, forest-grassland(FG) ecotone, and agriculture-forestgrassland(AFG) ecotone moved from the arid southeast to the humid northwest. The flat area with small slope is more edge-fragmented than the steep area since the ED decreases as the slope increases. The AF ecotone mostly found in the humid region is moving to more humid areas while the agriculture-grassland(AG) ecotone mostly found in the dry region is moving towards the drier region.YU Lingxue ZHANG Shuwen LIU Tingxiang TANG Junmei BU Kun YANG Jiuchun 2015Chinese Geographical Science2015,25,2:4
8China's Wetland Databases Based on Remote Sensing Technology显示文摘Wetland databases can provide the basic data that necessary for the protection and management of wetlands. A large number of wetland databases have been established in the world as well as in China. In this paper, we review China's wetland databases based on remote sensing(RS) technology after introducing the background theory to the application of RS technology in wetland surveys. A key conclusion is that China's wetland databases are far from sufficient in fulfilling protection and management needs. Our recommendations focus on the use of the hyper-spectral imagery, microwave data, multi-temporal images, and automatic classifications in order to improve the accuracy and efficiency of wetland inventory. Further, attention should also be paid to detect major biophysical features of wetlands and build wetland databases in years after the 1980 s in China. Considering that great gap exists between RS experts and wetland experts, further cooperation between wetland scientists and RS scientists are needed to promote the application of RS in the foundation of wetland databases.YAN Fengqin LIU Xingtu CHEN Jing YU Lingxue YANG Chaobin CHANG Liping YANG Jiuchun ZHANG Shuwen 2017Chinese Geographical Science2017,27,3:4
9The relationships between land use change and demographic dynamics in western Jilin province显示文摘人口统计的变化被认为是最主修陆地使用变化的司机尽管有包含的几交往因素,特别在发展中的国家。在这份报纸,我们作为学习区域在中国选择了西方的吉林省为从 1975 ~ 2010 理解在陆地使用变化和人口动力学的空间时间的模式之间的关系提供案例研究。结果证明农田区域百分比的变化能被使用二次的功能建模很好,农田的最少的区域百分比在人口密度是 0 people/km 的区域是15.4%<啜class=“ a-plus-plus ”>当人口密度是 199.25 people/km 时, 2 ,和农田区域百分比有94.8%的最大的价值<啜class=“ a-plus-plus ”> 2 。草地,水身体和沼泽地的区域百分比指数地减少了,人口密度增加了。在陆地使用度和人口密度之间的关系能被使用逻辑回归建模很好模型。由于经济生长和工艺的进步和空村庄现象的存在,陆地使用度仍然在人口密度是否定生长的区域增加了。另外,陆地使用动力学与人口密度变化指数地增加了。树林的陆地使用亲戚变化,草地,布满建筑物土地和沼泽地与人口密度变化成正比。根据陆地使用结构和陆地使用的模拟结果,度, Daan 和 Zhenlai 有最大的可能性进一步被回收。作为敏感、易碎的区域,在 Tongyu 和 Qianan 上学习环境保护和 ecologic 建设具有意义。LI Fei ZHANG Shuwen BU Kun YANG Jiuchun WANG Qing CHANG Liping 2015Journal of Geographical Sciences2015,25,5:3
10A MODIS Time Series Data Based Algorithm for Mapping Forest Fire Burned Area显示文摘Burned area mapping is an essential step in the forest fire research to investigate the relationship between forest fire and climate change and the effect of forest fire on carbon budgets. This study proposed an algorithm to map forest fire burned area using the Moderate-Resolution Imaging Spectroradiameter (MODIS) time series data in Heilongjiang Province, China. The algorithm is divided into two steps: Firstly, the′core′pixels were extracted to represent the most possible burned pixels based on the comparison of the temporal change of Global Environmental Monitoring Index (GEMI), Burned Area Index (BAI) and MODIS active fire products between pre- and post-fires. Secondly, a 15-km distance was set to extract the entire burned areas near the′core′pixels as more relaxed conditions were used to identify the fire pixels for reducing the omission error as much as possible. The algorithm comprehensively considered the thermal characteristics and the spectral change between pre-and post-fires, which are represented by the MODIS fire products and the spectral index, respectively. Tahe, Mohe and Huma counties of Heilongjiang Province, China were chosen as the study area for burned area mapping and a time series of burned maps were produced from 2000 to 2011. The results show that the algorithmYANG Wei ZHANG Shuwen TANG Junmei BU Kun YANG Jiuchun CHANG Liping 2013Chinese Geographical Science2013,23,3:3
11Integrating geographical data and phenological characteristics derived from MODIS data for improving land cover mapping显示文摘学习为大区域的陆地盖子与地理数据和 phenological 特征的联合印射开发了一个可行方法,拿象学习区域的东北中国(NEC ) 。与降水和温度数据集的每月的一般水准,首先,空间聚类方法被用来把 NEC 划分成四个 ecoclimate 区域。为每个 ecoclimate 区域,地理变量(年度吝啬的 降水和温度,举起,斜坡和方面)与变量从中等决定成像分光辐射函数( MODIS )导出的 phenological 被相结合数据(提高的植被索引( EVI )和陆地表面浇索引( LSWI )),当土地的输入变量盖住分类,它被拿。决定树(DT ) 分类器然后被执行为每个区域生产陆地盖子地图。最后,四张结果的陆地盖子地图是 mosaicked 因为全部 NEC (NEC_MODIS ) ,和陆地使用并且登陆从 Landsat-TM 图象解释的 NEC (NEC_LULC ) 的盖子数据被用来评估 NEC_MODIS, MODIS 们以 areal 和空间同意打盖子产品(MODIS_IGBP ) 。结果证明 phenological 信息源于 EVI, LSWI 时间系列很好在 NEC 区别了陆地盖子班,并且全面精确性被 5.29% 显著地与地理变量的增加改进。与为七个聚集班的 NEC_LULC 相比, NEC_MODIS 的区域错误比 MODIS_IGBP 的小得多、更稳定因为大多数班,和在象素水平的铺满地板的空间比较显示 NEC_MODIS 为 71.26% NEC 同意了 NEC_LULC,而仅仅 62.16% 为 MODIS_IGBP。NEC_MODIS 的好表演证明在学习开发的方法论为及时、详细说明的陆地盖子在适度、北方的区域印射有大潜力。CAI Hongyan ZHANG Shuwen BU Kun YANG Jiuchun CHANG Liping 2011Journal of Geographical Sciences2011,21,4:2
12Modeling and simulation of AC-DC-AC converter for MW-level direct-drive system wind turbine interface grid 显示文摘CHUANWEI YANG HUI LIANG JIUCHUN JIANG 2006IEEE Transactions on Energy Conversion2006,,3:1
13Microstructure characteristics and performance of dissimilar welds between magnesium alloy and aluminum formed by friction stirring显示文摘Jiuchun Yan Zhiwu Xu Zhiyuan Li Lei Li Shiqin Yang 2005Scripta Materialia2005,,5:1
14Interface structure changes during vibration liquid phase bonding of SiC p /A356 composites in air显示文摘Huibin Xu Jiuchun Yan Zhiwu Xu Baoyou Zhang Shiqin Yang 2005Composites Part A2005,,9:1
15Modeling and simulation of AC-DC-AC converter system for MW-level direct-drive wind turbine grid interface显示文摘Chuanwei Yang Hui Liang Jiuchun Jiang 2005IEEE Applied Power Electronics Conference and Exposition2005,1,9:1
16Interface structure and strength of ultrasonic vibration liquid phase bonded joints of Al 2 O 3p /6061Al composites显示文摘Zhiwu Xu Jiuchun Yan Gaohui Wu Xiangli Kong Shiqin Yang 2005Scripta Materialia2005,,7:1
17Modeling and Simulation of AC-DC-AC Converter System for MW-Level Direct-Drive Wind Turbine grid Interface 显示文摘Chuanwei Yang Hui Liang Jiuchun Jiang 2006Power Electronics Specialists Conference2006,1822,:1
18Ultrasonicdissolution of brazing of 55% SiCp/A356 composites显示文摘Zhang Yang Yan Jiuchun Chen Xiaoguang 2009Transactions of Nonferrous Metals Society of China2009,,3:1
19Simulation on Magnetostriction Strain of Polymer-bonded Terfenol-D Composites显示文摘A model of magnetostrictive strain for polymer-bonded Terfenol-D composite is presented, which is composed of asubmodel for the average strain of Terfenol-D composite and a magnetostriction submodel for Terfenol-D particles.Simulated results show that the saturation magnetostriction λs is very closely with experimental results, althoughthere exists some difference between the calculated and the experimental results under low applied magnetic field.The saturation magnetostriction of the composites increases with the particle fraction (v1=72.5~90 vol. Pct) in thesimulated and experimental results, but the simulation result is not ideal when the particle fraction is higher than 85%.Jiuchun YAN Shixiong LU Shiqin YANG Shiyu HE 2003Journal of Materials Science & Technology2003,19,z1:0
20Changes in Climate Factors and Their Impacts on Wind Erosion Climatic Erosivity in Farming-pastoral Zone of Northern China显示文摘Climate change can affect wind erosion power and hence induce changes in wind erosion rates.In this study,the wind erosion climate factor(C-factor),proposed by the Food and Agriculture Organization of the United Nations,was used to assess the impact of changes in climate on wind erosion climatic erosivity.The Mann-Kendall test was employed to detect trends in the C-factor during the period of 1961–2017 in the farming-pastoral zone of northern China.Sensitivity analysis was used to determine the sensitivity of the C-factor to changes in key climate factors.Furthermore,a comparison of the contributions of different climate factors was carried out to understand their impact on changes in the C-factor.The results indicated that most of the surveyed region exhibited decreasing trends in wind speed at a confidence level of 90%,while maximum and minimum temperatures showed increasing trends throughout the study area.As a consequence of decreasing wind speed,the annual C-factor exhibited significant decreasing trends,with a mean slope of–0.58/yr.Seasonal analysis revealed that in most regions,the changes in the C-factor had significant decreasing trends in spring,winter,and autumn,while in more than two-thirds of the study area,no significant change trends in the C-factor were detected in summer at a confidence level of 90%.Sensitivity analysis showed that the C-factor was most sensitive to wind speed,and that the sensitivity coefficients from July to September were much higher than those in other months.Contribution analysis revealed that,for most stations,wind speed(with greater values of sensitivity coefficients)was the dominant factor in the change of C-factor,while for some stations,the minimum temperature made the most contribution to the C-factor’s change due to its dramatic changes during the study period.Although the minimum temperature sensitivity coefficient was the lowest of all the sensitivity coefficients,it is urgent to evaluate the expected impact of minimum temperature due to its possible changes in the future.YUE Shuping YAN Yechao ZHANG Shuwen YANG Jiuchun 2022Chinese Geographical Science2022,32,4:0
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