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Variational Calculation for Large Bipolarons in Arbitrary Dimensions

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Chinese Physics Letters 1994年第6期11卷 361-364页

作者： CHEN Qinghu WAN Shaolong wang kelin Center for Fundamental Physics University of Science and Technology of ChinaHefei 230026

The calculation model of the large bipolaron binding energy proposed by Verbist et *** extended to arbitrary dimensions including fractal *** is found that the fractal dimension D=1.25 corresponds to the lowest critical coupling constantα_(c)=1.9,D=1.73 corresponds to the highest critical ratio of dielectric constantsη_(c)=0.163,and when D≤1.145 bipolarons can not exist for any coupling constants and ratios of dielectric constants.

关键词： constants constants fractal

Fingerprinting sediment sources in a typical karst catchment of southwest China

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International Soil and Water Conservation Research 2020年第3期8卷 277-285页

作者： Zhenwei Li Xianli Xu Yaohua Zhang kelin wang Huanjiang Observation and Research Station for Karst Ecosystem Key Laboratory for Agro-Ecological Processes in Subtropical RegionInstitute of Subtropical AgricultureChinese Academy of SciencesChangsha410125China University of Chinese Academy of Sciences Beijing100049China

Due to the complex hydrogeological conditions in karst regions,it is difficult to measure sediment source contributions at a catchment scale *** objective of this study was to quantify the relative contributions of sediment sources and their temporal variability in a karst catchment in southwest *** depressions can trap eroded sediment similar to a dam or reservoir and,thus,are representative and typical test beds for identifying sediment sources in karst *** sediment cores were taken from a karst depression,58 soil samples from three potential sediment sources were collected,and 18 soil properties were *** relative contributions of cropland,forestland,and fissure or crack soils were calculated using a multivariate mixing *** fingerprinting results demonstrated that the cropland was the main sediment source in karst ***,according to the mean sediment contributions of the three deposited sediment cores,the sediment contribution from cropland topsoil was 69.3%,varying from 46.9%to 92.3%,and forestland soil and crack soil accounted for 8.6%and 22.1%of the sediment yield,and varying from 2.8%to 16.5%and 4.8%-36.6%,*** result indicated that great attention should be paid when using only a single core to quantify sediment *** to the deposited sediment was generally disturbed as cropland in the karst depression,the area that has not been disturbed in recent decades in depression was more appropriate to trace sediment sources in karst *** the best of our knowledge,this study was the first to quantify the contributions of sediment sources in the karst catchment of southwest *** study provides valuable information and a preliminary reference for applying a composite fingerprinting technique to quantify sediment sources in karst catchments.

关键词： Soil erosion Sedimentation Sediment tracing Earth's critical zone Ecohydrology

Bottom Simulating Reflector and Gas Seepage in Okinawa Trough:Evidence of Gas Hydrate in an Active Back-Arc Basin

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Journal of China University of Geosciences 2008年第2期19卷 152-161页

作者：栾锡武 kelin wang Roy Hyndman Eleanor Willoughby Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences （IOCAS） Qingdao 266071 China Pacific Geoscience Centre （PGC） Geological Survey of Canada Sidney V8L4B2 Canada

To look for gas hydrate, 22 multi-channel and 3 single-channel seismic lines on the East China Sea （ECS） shelf slope and at the bottom of the Okinawa Trough were examined. It was found that there was indeed bottom simulating reflector （BSR） occurrence, but it is very rare. Besides several BSRs, a gas seepage was also found. As shown by the data, both the BSR and gas seepage are all related with local geological structures, such as mud diapir, anticline, and fault-controlled graben-like structure. However, similar structural ＂anomalies＂ are quite common in the tectonically very active Okinawa Trough region, but very few of them have developed BSR or gas seepage. The article points out that the main reason is probably the low concentration of organic carbon of the sediment in this area. It was speculated that the rare occurrence of gas hydrates in this region is governed by structure-controlled fluid flow. Numerous faults and fractures form a network of high-permeability channels in the sediment and highly fractured igneous basement to allow fluid circulation and ventilation. Fluid flow in this tectonic environment is driven primarily by thermal buoyancy and takes place on a wide range of spatial scales. The fluid flow may play two roles to facilitate hydrate formation： to help gather enough methane into a small area and to modulate the thermal regime.

关键词： gas hydrate BSR gas seepage back-arc basin formation mechanism.

Human disturbance exacerbated erosion and deposition in the karst peak-cluster depressions during the Ming and Qing dynasties

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Science China Earth Sciences 2024年第11期67卷 3550-3561页

作者： Shuai YUAN Yuemin YUE Xinbao ZHANG Lu wang Lu ZHAI kelin wang Key Laboratory for Agro-Ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of SciencesHuanjiang 547100China University of Chinese Academy of Sciences Beijing 100049China Institute of Mountain Hazards and Environment Ministry of Water ResourcesChinese Academy of SciencesChengdu 610041China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550002China

Under the background of large-scale ecological restoration, China's southwestern karst region has become a hotspot of global vegetation cover “greening” in the past 20 years. However, because of geological constraints, it is difficult to restore the forest landscapes in some areas. It is urgent to understand the impacts of human disturbances during the historical period on the difficult-to-forestation rocky-desertification areas of the karst region in order to guide future afforestation. In this study, we quantified the changes of specific sediment yield in typical karst depressions over the past 500 years by using ^(137)Cs,^(210)Pb, and ^(14)C dating methods in karst depressions, and identified the main human disturbances related to historical erosion and sedimentation by combining with historical data. The results showed that the erosion and sedimentation of the three depressions in 1921–1963 were significantly higher than that in 1963–2021, and the sedimentation rate(0.64–1.33 cm a^(-1)) and the specific sediment yield(2.51–13.11 t ha^(-1)a^(-1)) during Ming and Qing dynasties(1504–1812) were higher than the sedimentation rate(0.26–0.95 cm a^(-1)) and specific sediment yield(0.95–6.99 t ha^(-1)a^(-1)) in the recent century(1921–2021). Reconstruction data and literature from the Ming and Qing dynasties show an empirical link between changes in population, arable land, food, forest area,and deforestation events during the same period. It was found that the population and arable land in Guangxi increased more than three-fold and the forest area decreased significantly in the 17th century after the migration of the Yao ethnic group and the introduction of maize to the region, which may be the main reason for intensifying the erosion of depressions. This study is of great significance to understanding the evolution history of rocky desertification in this region and to answer the potential of afforestation.

关键词： Karst region ^(14)C dating Peak-cluster depressions Ethnic minirity migration Specific sediment yield

Responses of Spatial-temporal Variation of Karst Ecosystem Service Values to Landscape Pattern in Northwest of Guangxi,China

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Chinese Geographical Science 2011年第4期21卷 446-453页

作者： ZHANG Mingyang wang kelin LIU Huiyu ZHANG Chunhua Key Laboratory for Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of SciencesHunan 410125China Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of SciencesHuanjiang 547100China College of Geography Science Nanjing Normal UniversityNanjing 210046China

The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest Guangxi Zhuang Autonomous Region,China,were examined us-ing remote sensing and geographic information system techniques in this *** total ecosystem service values de-clined significantly from 1985 to 1990,and then increased slowly from 1990 to 2005,almost equaled to the 1985 *** ecosystem service values tended to decline from the west to the east and from mountainous regions to peak-cluster depression areas in 1985,1990,2000 and 2005 *** the period from 1985 to 2005,the ecosystem ser-vice values have increased in the middle and eastern parts of the study *** pattern indices,such as total area,largest patch index,contagion,aggregative index,effective mesh and proportion of like adjacencies,are significantly correlated with ecosystem service *** suggests that ecosystem service values tend to increase with the growth of patch area and patch ***,there are negative correlations between ecosystem service values and landscape pattern indices,such as division index and patch *** indicates that ecosystem service values decrease with patch fragmentation and patch size *** ecosystem conditions in the typical Karst area have been improved because of the control measures of rocky *** is important to protect key landscape types,such as woodland,shrub and grassland,and to increase patch size and connectivity to avoid further ***,it is necessary to reduce disturbances to ensure the growth of ecosystem service values and to facilitate the sustainable development in this region.

关键词： landscape pattern ecosystem service values (ESVs) landscape indices Karst Guangxi

A Soliton Solution for MHD Equation of Unmagnetized Collisionless Plasma

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Chinese Physics Letters 1993年第9期10卷 527-530页

作者： wang kelin DING Weixing YU Changxuan Fuiidanientiil Physics Center.University of Science and Teclinology of China Hefei 230026 Department of Modern Physics University of Science and Technology of ChinaHefei 230026

A new theoretical method has been developed to deni with ion acoustic soliton in collisionless plasma,with cold ions(T_(e)>>T_(i)).The analytical soliton solution cfin be found from the magnetic hydrodynfimics equatio... 详细信息

关键词： equation soliton Soliton

Methods for cleaning turbid nematode suspensions collected from different land-use types and soil types

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Soil Ecology Letters 2022年第4期4卷 429-434页

作者： Jie Zhao kelin wang Key Laboratory of Agro-ecological Processes in Subtropical Region Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of SciencesHuanjiang 547100China

Soil nematodes are useful ecological indicators and can be extracted from soil by a variety of *** the extracted nematode samples(suspensions)can be quite turbid(i.e.,they contain soil particles and organic particles in addition to nematodes),quantitative and taxonomic analyses of the nematodes by microscopy can be *** this study,the following three methods for cleaning turbid suspensions obtained from Baermann funnels were assessed:repeated centrifugation at 692.5´g for 1 min,repeated settling at low-temperature(4°C)for 24 h,and a combination of low-temperature settling and *** were extracted with Baermann funnels from soil samples collected from four land-use types(since land-use type can affect the turbidity of nematode suspensions),and the resulting suspensions were cleaned by the three methods before nematode abundance was *** a control,samples(i.e.,suspensions)were simply diluted with water,and nematodes were counted in the entire *** results showed that,within each land-use type,nematode abundance did not significantly differ between the control and the three cleaning *** across all land-use types,however,the nematode recovery rate was slightly higher with repeated centrifugation than with the other two cleaning ***,the proposed methods are sound for cleaning turbid nematode suspensions,and repeated centrifugation is the most efficient method.

关键词： Soil nematodes Purification method Centrifugation Low-temperature settlement Luvisols Acrisols

Towards Achieving Carbon Neutrality: The Role of Vegetation Restoration in Karst Regions of Southwest China

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Journal of Earth Science 2024年第3期35卷 1044-1048页

作者： Yuemin Yue Lu wang Xinbao Zhang kelin wang Guangxi Key Laboratory of Karst Ecological Processes and Services Institute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125China Huanjiang Observation and Research Station for Karst Ecosystem Chinese Academy of SciencesHuanjiang 547100China Chengdu Institute of Mountain Disasters and Environment Chinese Academy of Sciences&Ministry of Water ResourcesChengdu 610041China

Karst regions of Southwest China become a hotspot for global greening through large-scale vegetation restoration in recent two ***,the unique,fragile geological setting of carbonate rocks affects the sustainability of vegetation ***,we summarize and evaluate the impacts of the rock and soil compositions of karst landscapes on the types and quality of vegetation *** introduce the concept of“soil mass”and establish its relationship with aboveground vegetation biomass across varying degrees of rocky *** mineral nutrients and soil mass constrain the potential of vegetation carbon sequestration in karst *** enhance the sustainability of vegetation restoration and carbon sequestration under karst geological constraints,we suggest to push ecological intensification of tree plantations and optimize the zoning and classification of rocky desertification treatment,and these restoration initiatives will foster vegetation restoration to serve as a pivotal pathway towards carbon neutrality.

关键词： soil karst Restoration

Features of the polaron ground state in one-dimensional Holstein model

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Science China(Physics,Mechanics & Astronomy) 2009年第9期52卷 1302-1306页

作者： REN XueZao LIAO Xu LI Lei wang kelin School of Science Southwest University of Science and TechnologyMianyang 621010China Department of Modern Physics University of Science and Technology of ChinaHefei 230026China

Applying the method of coherent state orthogonal expansion, we expand the trial wave functions of ground state to the third order. We find that the ground state energy of the system decreases with the increase of expansion orders. Especially, at the zeroth order approximation, the probability distribution of the electron at different sites exhibits a soliton peak. However, the probability distribution of the electron at each site becomes identical, when we expand the trial wave functions of ground state to the higher orders.

关键词： coherent-state orthogonal expansion polaron simulated annealing method