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Restoration of Folk Document Covers from the Qing Dynasty to the Republic of China
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作者 Jiao Yao Fujiang Geng +1 位作者 Huanhuan Wang Yunpei Lu 《Paper And Biomaterials》 CAS 2023年第3期66-74,共9页
The covers of booklets and books in folk documents primarily serve to protect the pages.Owing to long-term storage limitations,a considerable number of book covers have suffered varying degrees of damage.Following the... The covers of booklets and books in folk documents primarily serve to protect the pages.Owing to long-term storage limitations,a considerable number of book covers have suffered varying degrees of damage.Following the principles of restoration,a comparative analysis and restoration of folk document covers were conducted,selecting four different types of carriers from the Taihang Mountain Documents,ranging from the Qing dynasty to the Republican Era.These carriers included hemp,mulberry bark,and machinemade paper,and cotton blue cloth.Each cover type was matched with an appropriate restoration paper,and different methods were employed during the restoration process.Through restoration,the previously damaged document covers can continue to fulfill their role in protecting the books,thereby extending the lifespan of these four folk documents. 展开更多
关键词 RESTORATION folk documents covers
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Adding Value to Crop Production Systems by Integrating Forage Cover Crop Grazing
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作者 Robert B. Mitchell Daren D. Redfearn +9 位作者 Kenneth P. Vogel Terry J. Klopfenstein Galen Erickson P. Stephen Baenziger Bruce E. Anderson Mary E. Drewnoski Jay Parsons Steven D. Masterson Marty R. Schmer Virginia L. Jin 《American Journal of Plant Sciences》 CAS 2024年第3期180-192,共13页
In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance... In addition to their value as cereal grains, wheat (Triticum aestivum L.) and triticale (× Triticosecale Wittmack) are important cool-season annual forages and cover crops. Yearling steer (Bos taurus) performance was compared in the spring following autumn establishment as for age cover crops after soybean [Glycine max (L.) Merr.] grain harvest. Replicated pastures (0.4 ha) were no-till seeded in three consecutive years into soybean stubble in autumn, fertilized, and grazed the following spring near Ithaca, NE, USA. Each pasture (n = 3) was continuously stocked in spring with four yearling steers (380 ± 38 kg) for 17, 32, and 28 d in 2005, 2006, and 2007, respectively. In 2005, average daily gain (ADG) for steers grazing triticale exceeded the ADG for wheat by 0.31 kghd<sup>-1</sup>d<sup>-1</sup>. In 2006, wheat ADG exceeded that for triticale by 0.12 kghd<sup>-1</sup>d<sup>-1</sup>. In 2007, steers grazing wheat lost weight, while steers grazing triticale gained 0.20 kghd<sup>-1</sup>d<sup>-1</sup>. Based on the 3-year average animal gains valued at $1.32 kg<sup>-1</sup>, mean net return ($ ha<sup>-1</sup> yr<sup>-1</sup>) was $62.15 for triticale and $22.55 for wheat. Since these grazed cover crops provide ecosystem services in addition to forage, grazing could be viewed as a mechanism for recovering costs and adds additional value to the system. Based on this 3-year grazing trial, triticale was superior to wheat and likely will provide the most stable beef yearling performance across years with variable weather for the western Cornbelt USA. 展开更多
关键词 cover crops SOYBEAN TRITICALE WHEAT
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Modelling Land Use/Land Cover Change of River Rwizi Catchment, South-Western Uganda Using GIS and Markov Chain Model
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作者 Lauben Muhangane Morgan Andama 《Journal of Water Resource and Protection》 CAS 2024年第2期181-206,共26页
Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 19... Analysis of catchment Land use/Land cover (LULC) change is a vital tool in ensuring sustainable catchment management. The study analyzed land use/land cover changes in the Rwizi catchment, south western Uganda from 1989-2019 and projected the trend by 2040. Landsat images, field observations, key informant interviews and focus group discussions were used to collect data. Changes in cropland, forestland, built up area, grazing land, wetland and open water bodies were analyzed in ArcGIS version 10.2.2 and ERDAS IMAGINE 14 software and a Markov chain model. All the LULC classes increased in area except grazing land. Forest land and builtup area between 2009-2019 increased by 370.03% and 229.53% respectively. Projections revealed an increase in forest land and builtup area by 2030 and only built up area by 2040. LULCC in the catchment results from population pressure, reduced soil fertility and high value of agricultural products. 展开更多
关键词 Land cover River Catchment Geographic Information System Markov Model Sustainable Land Management
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Changes in Spring Snow Cover over the Eastern and Western Tibetan Plateau and Their Associated Mechanism
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作者 Fangchi LIU Xiaojing JIA Wei DONG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第5期959-973,共15页
The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–2020.The current work investigate... The spring snow cover(SC)over the western Tibetan Plateau(TP)(TPSC)(W_TPSC)and eastern TPSC(E_TPSC)have displayed remarkable decreasing and increasing trends,respectively,during 1985–2020.The current work investigates the possible mechanisms accounting for these distinct TPSC changes.Our results indicate that the decrease in W_TPSC is primarily attributed to rising temperatures,while the increase in E_TPSC is closely linked to enhanced precipitation.Local circulation analysis shows that the essential system responsible for the TPSC changes is a significant anticyclonic system centered over the northwestern TP.The anomalous descending motion and adiabatic heating linked to this anticyclone leads to warmer temperatures and consequent snowmelt over the western TP.Conversely,anomalous easterly winds along the southern flank of this anticyclone serve to transport additional moisture from the North Pacific,leading to an increase in snowfall over the eastern TP.Further analysis reveals that the anomalous anticyclone is associated with an atmospheric wave pattern that originates from upstream regions.Springtime warming of the subtropical North Atlantic(NA)sea surface temperature(SST)induces an atmospheric pattern resembling a wave train that travels eastward across the Eurasian continent before reaching the TP.Furthermore,the decline in winter sea ice(SIC)over the Barents Sea exerts a persistent warming influence on the atmosphere,inducing an anomalous atmospheric circulation that propagates southeastward and strengthens the northwest TP anticyclone in spring.Additionally,an enhancement of subtropical stationary waves has resulted in significant increases in easterly moisture fluxes over the coastal areas of East Asia,which further promotes more snowfall over eastern TP. 展开更多
关键词 snow cover Tibetan Plateau long-term changes SPRING
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Glacier area change (1993-2019) and its relationship to debris cover, proglacial lakes, and morphological parameters in the Chandra-Bhaga Basin, Western Himalaya, India
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作者 VATSAL Sarvagya AZAM Mohd Farooq +5 位作者 BHARDWAJ Anshuman MANDAL Arindan BAHUGUNA Ishmohan RAMANATHAN Alagappan RAJU N.Janardhana TOMAR Sangita Singh 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1287-1306,共20页
Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years... Glacier inventories serve as critical baseline data for understanding the impacts of climate change on glaciers.The present study maps the outlines of glaciers in the Chandra-Bhaga Basin(western Himalaya)for the years 1993,2000,2010,and 2019 using Landsat Thematic Mapper(TM),Enhanced Thematic Mapper(ETM),and Operational Land Imager(OLI)datasets.A total of 251 glaciers,each having an area above 0.5 km^(2),were identified,which include 216 clean-ice and 35 debris-covered glaciers.Area changes are estimated for three periods:1993-2000,2000-2010,and 2010-2019.The total glacierized area was 996±62 km^(2) in 1993,which decreased to 973±70 km^(2) in 2019.The mean rate of glacier area loss was higher in the recent decade(2010-2019),at 0.036 km^(2),compared to previous decades(0.029 km^(2) in 2000-2010 and 0.025 km^(2) in 1993-2000).Supraglacial debris cover changes are also mapped over the period of 1993 and 2019.It is found that the supraglacial debris cover increased by 14.12±2.54 km^(2)(15.2%)during 1993-2019.Extensive field surveys on Chhota Shigri,Panchi II,Patsio,Hamtah,Mulkila,and Yoche Lungpa glaciers were carried out to validate the glacier outlines and supraglacial debris cover estimated using satellite datasets.Controls of various morphological parameters on retreat were also analyzed.It is observed that small,clean ice,south oriented glaciers,and glaciers with proglacial lakes are losing area at faster rates than other glaciers in the basin. 展开更多
关键词 GLACIER Area change Debris cover MORPHOLOGY Proglacial lake
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Land use and cover change and influencing factor analysis in the Shiyang River Basin,China
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作者 ZHAO Yaxuan CAO Bo +4 位作者 SHA Linwei CHENG Jinquan ZHAO Xuanru GUAN Weijin PAN Baotian 《Journal of Arid Land》 SCIE CSCD 2024年第2期246-265,共20页
Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and ... Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas. 展开更多
关键词 land use and cover classification land use and cover change(LUCC) climate change random forest accuracy assessment three-dimensional sampling method Shiyang River Basin
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Assessment of vegetation cover changes and the contributing factors in the Al-Ahsa Oasis using Normalized Difference Vegetation Index(NDVI)
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作者 Walid CHOUARI 《Regional Sustainability》 2024年第1期42-53,共12页
The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influ... The abandonment of date palm grove of the former Al-Ahsa Oasis in the eastern region of Saudi Arabia has resulted in the conversion of delicate agricultural area into urban area.The current state of the oasis is influenced by both expansion and degradation factors.Therefore,it is important to study the spatiotemporal variation of vegetation cover for the sustainable management of oasis resources.This study used Landsat satellite images in 1987,2002,and 2021 to monitor the spatiotemporal variation of vegetation cover in the Al-Ahsa Oasis,applied multi-temporal Normalized Difference Vegetation Index(NDVI)data spanning from 1987 to 2021 to assess environmental and spatiotemporal variations that have occurred in the Al-Ahsa Oasis,and investigated the factors influencing these variation.This study reveals that there is a significant improvement in the ecological environment of the oasis during 1987–2021,with increase of NDVI values being higher than 0.10.In 2021,the highest NDVI value is generally above 0.70,while the lowest value remains largely unchanged.However,there is a remarkable increase in NDVI values between 0.20 and 0.30.The area of low NDVI values(0.00–0.20)has remained almost stable,but the region with high NDVI values(above 0.70)expands during 1987–2021.Furthermore,this study finds that in 1987–2002,the increase of vegetation cover is most notable in the northern region of the study area,whereas from 2002 to 2021,the increase of vegetation cover is mainly concentrated in the northern and southern regions of the study area.From 1987 to 2021,NDVI values exhibit the most pronounced variation,with a significant increase in the“green”zone(characterized by NDVI values exceeding 0.40),indicating a substantial enhancement in the ecological environment of the oasis.The NDVI classification is validated through 50 ground validation points in the study area,demonstrating a mean accuracy of 92.00%in the detection of vegetation cover.In general,both the user’s and producer’s accuracies of NDVI classification are extremely high in 1987,2002,and 2021.Finally,this study suggests that environmental authorities should strengthen their overall forestry project arrangements to combat sand encroachment and enhance the ecological environment of the Al-Ahsa Oasis. 展开更多
关键词 Normalized Difference Vegetation Index(NDVI) Vegetation cover Ecological environment Land use and land cover(LULC) Urban expansion Al-Ahsa Oasis
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Land Use Land Cover Analysis for Godavari Basin in Maharashtra Using Geographical Information System and Remote Sensing
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作者 Pallavi Saraf Dattatray G. Regulwar 《Journal of Geographic Information System》 2024年第1期21-31,共11页
The dynamic transformation of land use and land cover has emerged as a crucial aspect in the effective management of natural resources and the continual monitoring of environmental shifts. This study focused on the la... The dynamic transformation of land use and land cover has emerged as a crucial aspect in the effective management of natural resources and the continual monitoring of environmental shifts. This study focused on the land use and land cover (LULC) changes within the catchment area of the Godavari River, assessing the repercussions of land and water resource exploitation. Utilizing LANDSAT satellite images from 2009, 2014, and 2019, this research employed supervised classification through the Quantum Geographic Information System (QGIS) software’s SCP plugin. Maximum likelihood classification algorithm was used for the assessment of supervised land use classification. Seven distinct LULC classes—forest, irrigated cropland, agricultural land (fallow), barren land, shrub land, water, and urban land—are delineated for classification purposes. The study revealed substantial changes in the Godavari basin’s land use patterns over the ten-year period from 2009 to 2019. Spatial and temporal dynamics of land use/cover changes (2009-2019) were quantified using three Satellite/Landsat images, a supervised classification algorithm and the post classification change detection technique in GIS. The total study area of the Godavari basin in Maharashtra encompasses 5138175.48 hectares. Notably, the built-up area increased from 0.14% in 2009 to 1.94% in 2019. The proportion of irrigated cropland, which was 62.32% in 2009, declined to 41.52% in 2019. Shrub land witnessed a noteworthy increase from 0.05% to 2.05% over the last decade. The key findings underscored significant declines in barren land, agricultural land, and irrigated cropland, juxtaposed with an expansion in forest land, shrub land, and urban land. The classification methodology achieved an overall accuracy of 80%, with a Kappa Statistic of 71.9% for the satellite images. The overall classification accuracy along with the Kappa value for 2009, 2014 and 2019 supervised land use land cover classification was good enough to detect the changing scenarios of Godavari River basin under study. These findings provide valuable insights for discerning land utilization across various categories, facilitating the adoption of appropriate strategies for sustainable land use in the region. 展开更多
关键词 GIS Remote Sensing Land Use Land cover Change Change Detection Supervised Classification
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Changes in snow cover extent in the Central Taurus Mountains from 1981 to 2021 in relation to temperature, precipitation, and atmospheric teleconnections
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作者 Ecmel ERLAT Fulya AYDIN-KANDEMİR 《Journal of Mountain Science》 SCIE CSCD 2024年第1期49-67,共19页
The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central ... The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. In this study, we analyzed the monthly Snow Cover Extent(SCE) from November to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(November to April) over the last 41 years showed decreases in SCE primarily at lower elevations. The downward trend in SCE was found to be more pronounced and statistically significant for only November and March. SCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in November and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of SCE has become evident since the 2000s, and the lowest negative anomalies in SCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. SCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between SCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the North Atlantic Oscillation(NAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in SCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter SCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, NAO and MO, especially below 2000 m elevation. 展开更多
关键词 Snow cover extent Atmospheric teleconnection Central Taurus Mountains Air temperature and precipitation Geographic Information Systems Türkiye
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Research on the Control Cover against Solenopsis invicta and Rapid Extinguishment of Its Epidemic
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作者 Hongyi WANG Jun HONG +1 位作者 Haoyuan ZHU Xueying HAN 《Plant Diseases and Pests》 2024年第2期1-3,8,共4页
Based on the biological characteristics of Solenopsis invicta and the structural characteristics of its ant nest,a fast and efficient closed treatment device was developed.Compared with the simple chemical treatment c... Based on the biological characteristics of Solenopsis invicta and the structural characteristics of its ant nest,a fast and efficient closed treatment device was developed.Compared with the simple chemical treatment commonly used at present,the developed treatment device(the ant nest control cover)is a fast and efficient method to exterminate S.invicta in 7 d,featured by short course,quick results and good effect. 展开更多
关键词 Alien invasive species Solenopsis invicta Control cover Epidemic extinguishment technology
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Trends of Land Use and Land Cover Change in the Savannah Ecological of the Protected Area Reserve Partielle de Dosso, Niger
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作者 Amadou Issoufou Abdourhimou Moussa Boubacar +2 位作者 Habou Rabiou Soumana Idrissa Mahamane Ali 《Natural Resources》 2024年第3期61-68,共8页
Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case stu... Information on the dynamics of savannah is important to a country's plan to overcome the problems of uncontrolled development and environmental hazards. Taking the reserve partielle de Dosso, Niger as the case study area, this paper analyzed the long-term land use land cover change from 2002 to 2022. Satellite images were processed by using Google Earth Engine (GEE). Therefore, four major land cover classes were identified based on spectral characteristics of Land sat, namely, built-up, vegetation, cropland, bare land and water. The result revealed that barren and built-up areas increased at the expense of vegetation and water. From the four major land use land cover the large area is covered by vegetation which comprises about 192963.5 hectares followed by cropland and water consisting of 32506.43 and 1596.4 hectares respectively. The built-up area gained substantial area (most) during the study period. The reduction in some of the land cover/uses underlines the dangerous trend of the pressure poised by population growth and the changing functionality. Land cover change is influenced by a variety of societal factors operating on several spatial and temporal levels. The area estimates and spatial distributions of the LULC classes produced from the current study will assist local authorities, managers, and other stakeholders in decision-making and planning regarding forest land cover and uses. 展开更多
关键词 Land Use/cover Change Detection CLASSIFICATION Dosso
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Migration and Spatiotemporal Land Cover Change: A Case of Bosomtwe Lake Basin, Ghana
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作者 Richard Kwabena Adams Lingling Zhang Zongzhi Wang 《Advances in Remote Sensing》 2024年第1期18-40,共23页
Internal migration is highly valued due to its increasingly acknowledged potential for social and economic development. However, despite its significant contribution to the development of towns and cities, it has led ... Internal migration is highly valued due to its increasingly acknowledged potential for social and economic development. However, despite its significant contribution to the development of towns and cities, it has led to the deterioration of many ecosystems globally. Lake Bosomtwe, a natural Lake in Ghana and one of the six major meteoritic lakes in the world is affected by land cover changes caused by the rising effects of migration, population expansion, and urbanization, owing to the development of tourist facilities on the lakeshore. This study investigated land cover change trajectories using a post-classification comparison approach and identified the factors influencing alteration in the Lake Bosomtwe Basin. Using Landsat imagery, an integrated approach of remote sensing, geographical information systems (GIS), and statistical analysis was successfully employed to analyze the land cover change of the basin. The findings show that over the 17 years, the basin’s forest cover decreased significantly by 16.02%, indicating that population expansion significantly affects changes in land cover. Ultimately, this study will raise the awareness of stakeholders, decision-makers, policy-makers, government, and non-governmental agencies to evaluate land use development patterns, optimize land use structures, and provide a reference for the formulation of sustainable development policies to promote the sustainable development of the ecological environment. 展开更多
关键词 Land cover Change Supervised Classification MIGRATION Landsat Imagery Environmental Sustainability
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Spatiotemporal characteristics and driving mechanisms of land use/land cover(LULC)changes in the Jinghe River Basin,China
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作者 WANG Yinping JIANG Rengui +4 位作者 YANG Mingxiang XIE Jiancang ZHAO Yong LI Fawen LU Xixi 《Journal of Arid Land》 SCIE CSCD 2024年第1期91-109,共19页
Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and... Understanding the trajectories and driving mechanisms behind land use/land cover(LULC)changes is essential for effective watershed planning and management.This study quantified the net change,exchange,total change,and transfer rate of LULC in the Jinghe River Basin(JRB),China using LULC data from 2000 to 2020.Through trajectory analysis,knowledge maps,chord diagrams,and standard deviation ellipse method,we examined the spatiotemporal characteristics of LULC changes.We further established an index system encompassing natural factors(digital elevation model(DEM),slope,aspect,and curvature),socio-economic factors(gross domestic product(GDP)and population),and accessibility factors(distance from railways,distance from highways,distance from water,and distance from residents)to investigate the driving mechanisms of LULC changes using factor detector and interaction detector in the geographical detector(Geodetector).The key findings indicate that from 2000 to 2020,the JRB experienced significant LULC changes,particularly for farmland,forest,and grassland.During the study period,LULC change trajectories were categorized into stable,early-stage,late-stage,repeated,and continuous change types.Besides the stable change type,the late-stage change type predominated the LULC change trajectories,comprising 83.31% of the total change area.The period 2010-2020 witnessed more active LULC changes compared to the period 2000-2010.The LULC changes exhibited a discrete spatial expansion trend during 2000-2020,predominantly extending from southeast to northwest of the JRB.Influential driving factors on LULC changes included slope,GDP,and distance from highways.The interaction detection results imply either bilinear or nonlinear enhancement for any two driving factors impacting the LULC changes from 2000 to 2020.This comprehensive understanding of the spatiotemporal characteristics and driving mechanisms of LULC changes offers valuable insights for the planning and sustainable management of LULC in the JRB. 展开更多
关键词 land use/land cover(LULC)changes driving mechanisms trajectory analysis geographical detector(Geodetector) Grain for Green Project Jinghe River Basin
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AN EXPERIMENTAL STUDY OF INFILTRATION AND EROSION UNDER SLOPE GRADIENTS AND VEGETAL COVERS 被引量:5
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作者 Jin Changxing Cai Qiangguo(Institute of Geography, CAS, Beijing 100101, China)Wang Zhongke(Soil Conservation Experimental Station, Zhangjiakou, Hebei Province 075000, China) 《Journal of Geographical Sciences》 SCIE CSCD 1995年第4期62-73,共12页
The effect of slope gradient and vegetal cover on soil infiltration and erosion were studied with field simulator. Results showed that infiltration decreases with slope gradients (especially for gradient less than 10&... The effect of slope gradient and vegetal cover on soil infiltration and erosion were studied with field simulator. Results showed that infiltration decreases with slope gradients (especially for gradient less than 10°) and increases with vegetal covers, while soil erosion increases with slope gradients and decreases with vegetal covers. Fittlng the data by Philip's infiltration equation it was found that in the equation, gravitational conductivity decreases with gradient and increases with vegetation, while diffusion decreases with vegetal cover and does not vary with slope gradient In the erosion process, the formation of a layer of thin water is crucial in dctermining the rainsplash and sheetwash. The increasing of erosion with slope gradient contributes mainly to the increase of velocity. 展开更多
关键词 INFILTRATION EROSION slope gradient vegetal cover
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Experimental study and simulations of infiltration in evapotranspiration landfill covers 被引量:1
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作者 Wen-xian ZHANG Zhan-yu ZHANG Kang WANG 《Water Science and Engineering》 EI CAS 2009年第3期96-109,共14页
Various cover systems have been designed for landfill sites in order to minimize infiltration (percolation) into the underlying waste. This study evaluated the soil water balance performance of evapotranspiration co... Various cover systems have been designed for landfill sites in order to minimize infiltration (percolation) into the underlying waste. This study evaluated the soil water balance performance of evapotranspiration covers (ET covers) and simulated percolation in the systems using the active region model (ARM). Experiments were conducted to measure water flow processes and water balance components in a bare soil cover and different ET covers. Results showed that vegetation played a critical role in controlling the water balance of the ET covers. In soil profiles of 60-cm depth with and without vegetation cover, the maximum soil water storage capacities were 97.2 mm and 62.8 mm, respectively. The percolation amount in the bare soil was 2.1 times that in the vegetation-covered soil. The ARM simulated percolation more accurately than the continuum model because it considered preferential flow. Numerical simulation results also indicated that using the ET cover system was an effective way of removing water through evanotransoiration, thus reducing nercolation. 展开更多
关键词 active region model evapotranspiration cover percolation control water balance
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Use of Evapotranspiration (ET) Landfill Covers to Reduce Methane Emissions from Municipal Solid Waste Landfills 被引量:1
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作者 Tarek Abichou Tarek Kormi +3 位作者 Cheng Wang Haykel Melaouhia Terry Johnson Stephen Dwyer 《Journal of Water Resource and Protection》 2015年第13期1087-1097,共11页
Solid waste landfills need to have final covers to 1) reduce the infiltration of rainfall into the waste mass and 2) reduce surface greenhouse gas emissions. Most regulations require that such final covers include hyd... Solid waste landfills need to have final covers to 1) reduce the infiltration of rainfall into the waste mass and 2) reduce surface greenhouse gas emissions. Most regulations require that such final covers include hydraulic barriers, such as compacted clays with or without geomembrane. Significant research has been undertaken to allow the use of evapotranspiration-based covers (often termed: Evapotranspiration (ET) Cover, Water Balance Covers, or Phyto Covers) as an alternative to the barrier concept covers. ET covers are designed so that they have the capacity to store water by the soil and also have plants or vegetation to remove the stored water. In ET covers, plant roots can enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil. Therefore, biological methane oxidation (a natural process in landfill soils) can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This paper summarizes a study to investigate the capacity of an ET cover to reduce surface greenhouse gas emissions when implemented on a solid waste landfill. This study consisted of using a numerical model to estimate methane emission and oxidation through an ET cover under average climatic conditions in Bennignton, Nebraska, USA. Different simulations were performed using different methane loading flux (5 to 200 gm-2·d-1) as the bottom boundary. For all simulations, surface emissions were the lowest during the growing season and during warmer days of the year. Percent oxidation is the highest during the growing season and during warmer days. The lowest modeled surface emissions were always obtained during the growing season. Finally, correlations between percent oxidation and methane loading into simulated ET covers were proposed to estimate methane emissions and methane oxidation in ET covers. 展开更多
关键词 EVAPOTRANSPIRATION covers METHANE Oxidation LANDFILLS GREENHOUSE Gas Emissions
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Oyster Cementation as Protective Covers for Exposed Marine Concrete 被引量:1
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作者 吕建福 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第S1期217-220,共4页
Cored concrete specimens from seawall exposed to marine environment for 22 years were evaluated by carbonation depth test,rapid chloride permeability test,absorption of water test and microstructure examination.The re... Cored concrete specimens from seawall exposed to marine environment for 22 years were evaluated by carbonation depth test,rapid chloride permeability test,absorption of water test and microstructure examination.The results show that concrete exposed to marine environment has smaller carbonation depth and carbonation depth of concrete exposed to tidal zone is less than that in splash zone.There are similar water absorption rate and chloride permeability for concrete exposed to splash zone compared with concrete exposed to splash zone removed 3mm surface layer.However,concrete exposed to tidal zone with bio-films has lower chloride permeability and water absorption rate than those of concrete exposed to tidal zone removed 3mm surface layer.In addition,Results of FE-SEM and EDAX indicate that concrete exposed to splash zone has loose structure,exposed finer aggregate and concrete exposed to tidal zone covers by dense structure of oyster cementation and shell.Microstructures analysis further verified that concrete covered with oysters and their cementation has beneficial effects to durability of concrete. 展开更多
关键词 oyster cementation concrete exposed to marine environment protective cover concrete durability
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On L-injective Covers 被引量:1
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作者 周德旭 《Northeastern Mathematical Journal》 CSCD 2004年第2期207-216,共10页
We use the class of L-injective modules to define L-injective covers, and provide the characterizations of L-injective covers by the properties of kernels of homomorphisms. We prove that the right L-noetherian right L... We use the class of L-injective modules to define L-injective covers, and provide the characterizations of L-injective covers by the properties of kernels of homomorphisms. We prove that the right L-noetherian right L-hereditary ring is just such that every right R-module has an L-injective cover which is monic. We also use kernels of homomorphisms to investigate L-simple L-injective covers and give some constructions of L-simple L-injective covers. 展开更多
关键词 RING L-injective cover L-simple L-injective cover
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Farm-Scale Applicability of Three Covers (Peat, Polystyrene Balls and Synthetic Sheet Roof) to Reduce Ammonia Emissions from Pig Slurry Storage 被引量:1
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作者 Laurence Loyon Fabrice Guiziou +1 位作者 Sylvie Picard Patricia Saint-Cast 《Agricultural Sciences》 2016年第6期396-406,共11页
Covering the slurry pit has been shown to be one of the best ways to reduce ammonia emissions (NH<sub>3</sub>) during manure management. Yet, few studies have been conducted at farm scale. We studied the f... Covering the slurry pit has been shown to be one of the best ways to reduce ammonia emissions (NH<sub>3</sub>) during manure management. Yet, few studies have been conducted at farm scale. We studied the feasibility of three cover materials (peat, polystyrene balls and synthetic sheet roof) to reduce ammonia (NH<sub>3</sub>) emissions during on-farm storage of pig slurry. The impact on greenhouse gas emissions, methane (CH<sub>4</sub>), nitrous oxide (N<sub>2</sub>O) and carbon dioxide (CO<sub>2</sub>) of covering the slurry pit was also evaluated. Simultaneous field experiments were carried out using two similar pits at a farm with peat and polystyrene ball covers, which allowed direct comparison of the feasibility of the two covers to reduce gas emissions (measured using the dynamic chamber technique). Emissions from the third option (using a synthetic sheet roof) were estimated by measuring the concentrations in the headspace under the cover and the air leakage from the cover with a tracer gas (CO<sub>2</sub>). Results showed that the polystyrene balls cover reduced emissions of NH<sub>3</sub> during storage by up to 80% whatever the season, but increased potential greenhouse gas emissions by 20% in summer. No consistent reduction was achieved with the peat cover even though some individual results seemed to indicate up to 25% reduction in ammonia emissions;moreover, there was a 30% increase in CH<sub>4</sub> and CO<sub>2</sub> emissions during the storage period. The use of a synthetic sheet roof enabled up to 90% reduction in NH<sub>3</sub>, CH<sub>4</sub> and CO<sub>2</sub> emissions whatever the season. 展开更多
关键词 Ammonia SLURRY covers Farm-Scale Measurement Pig
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Improvement of Service Life of Small Furnace Covers on 150 t Refining Ladles
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作者 ZHANG Liang 《China's Refractories》 CAS 2020年第1期40-43,共4页
The factors restricting the life of the refining furnace cover were introduced,including the airflow erosion of the refining dust removal system,the melting loss caused by the arc radiation of the electrode,the chemic... The factors restricting the life of the refining furnace cover were introduced,including the airflow erosion of the refining dust removal system,the melting loss caused by the arc radiation of the electrode,the chemical erosion and penetration of slag and gas,and the condition of refining slag.The improvement measures are adjusting the material of the small furnace cover from corundum to chrome corundum,using a large shaking table to vibrate,optimizing the size design of the small furnace cover,and appropriately thickening the weak areas in the triangular area.The average service life of the refining furnace cover has been increased from one week to two months,reaching 4 maintenance cycles,which meets the needs of the refining production. 展开更多
关键词 REFINING LADLE FURNACE cover service LIFE measures
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