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“河西-山北回族走廊”刍议
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作者 沙彦奋 《青海民族研究》 CSSCI 北大核心 2013年第4期75-78,共4页
"民族走廊"已成为我国民族学等学科研究的一个重要理论,并形成了大量研究成果,对我国少数民族历史与文化研究带来了较大影响。基于民族走廊理论背景,提出"河西-山北回族走廊"的概念。从"河西-山北回族走廊&qu... "民族走廊"已成为我国民族学等学科研究的一个重要理论,并形成了大量研究成果,对我国少数民族历史与文化研究带来了较大影响。基于民族走廊理论背景,提出"河西-山北回族走廊"的概念。从"河西-山北回族走廊"内回族分布环境的多样性、回族"流动"历史的悠久性、回族"流动"的特殊性、回族文化的多样性等方面去认知"河西-山北回族走廊",认为其具有从整体上去理解西北回族"一体多元"和多民族"多元一体"的文化空间等学理价值和现实意义。 展开更多
关键词 “河西-山北回族走廊” 文化空间 文化整合
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青海乌兰茶卡棺板画研究 被引量:8
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作者 辛峰 马冬 《青海民族大学学报(社会科学版)》 2017年第3期1-9,共9页
在青海省海西州鸟兰县茶卡乡,海西州民族博物馆于2008年3月采集到了一批共4件北朝时期的彩棺残件,其上所绘各类吐谷浑人物棺板画从图像内容与结构观之,与河西魏晋墓葬画像砖之图像贴切度颇高,当是出于同一或近似之图像粉本。以历史时期... 在青海省海西州鸟兰县茶卡乡,海西州民族博物馆于2008年3月采集到了一批共4件北朝时期的彩棺残件,其上所绘各类吐谷浑人物棺板画从图像内容与结构观之,与河西魏晋墓葬画像砖之图像贴切度颇高,当是出于同一或近似之图像粉本。以历史时期先后、以及地理空间关系来看,前者应是受到了后者影响。鸟兰茶卡棺板画人物服饰具有鲜明的民族、时代与地域特征,其中的"缠头"与"羃(?)"应该是两种古代首服形制目前已知最早的考古图像,意义甚大。 展开更多
关键词 乌兰茶卡棺板画 “河西”因素 中古服饰
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Study on Spatial and Temporal Distribution Characteristics of Wind Energy Resource and Preservation in Central and West Hexi Corridor 被引量:3
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作者 郭良才 李红英 +2 位作者 于海跃 丑伟 相吉 《Agricultural Science & Technology》 CAS 2011年第3期451-455,共5页
[Objective] The aim was to explore the spatial and temporal distribution characteristics of wind energy resource and preservation in central and west area of Hexi Corridor. [Method] By dint of the wind speed data from... [Objective] The aim was to explore the spatial and temporal distribution characteristics of wind energy resource and preservation in central and west area of Hexi Corridor. [Method] By dint of the wind speed data from 1955 to 2007 in ten meteorological observation station in central and west area of Hexi Corridor,and special wind tower fine data from January to December in 2007,the distribution and reserves of the region's wind energy resources were studied. [Result] The results showed that environmental wind speed was relatively stable in central and west Hexi Corridor. There were no distinct changes in climate characteristics distribution. There were regional differences in the distribution of wind energy,and there was a large numerical area of wind energy in Gazhou County and Yumen City; Wind energy in the region generally was higher. The wind energy density was above 100 w/m2 in the 10 m layer,around 140 w/m2 in most places,and was more than 200 w/m2 in the large number area. The wind grew in vertical direction along with the linear growth of height. Each 10 m high wind increased to 15 w/m2 averagely,50m layer wind energy was greater than the general 240 w/m2 and there were obvious changes on daily and annual with wind energy in central and west area of Hexi Corridor. The duration from March to May was a wind energy-intensive stage,10m height from the ground in the wind around 10:00 in low-value. After growing from 11:00,it met the day largest number at 18:00,and then reduced gradually. Effective wind speed hours in the region in general were more than 6 200 h,and the value in the large areas was close to 7 600 h. [Conclusion] The study laid basis for the development and application of wind energy in central and west area of Hexi Corridor. 展开更多
关键词 Hexi Corridor Wind energy density RESERVES Effective speed
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法藏敦煌P.3861号文献的梵汉对音研究 被引量:3
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作者 孙伯君 《语言研究》 CSSCI 北大核心 2008年第4期17-24,共8页
法藏敦煌P-3861号文献中的梵汉对音资料所呈现的语音规律与《千字文》、《开蒙要训》等敦煌遗存资料大体一致,反映了八、九世纪吐蕃占领敦煌时期河西方音的特点,如清浊界限不甚分明,鼻音声母m、n、η有向mb、nd、ηg演化的迹象,舌上、... 法藏敦煌P-3861号文献中的梵汉对音资料所呈现的语音规律与《千字文》、《开蒙要训》等敦煌遗存资料大体一致,反映了八、九世纪吐蕃占领敦煌时期河西方音的特点,如清浊界限不甚分明,鼻音声母m、n、η有向mb、nd、ηg演化的迹象,舌上、齿头、正齿三组字混用,宕、梗、通摄-η尾消变,宕摄元音高化,-m、-n尾也有消变的痕迹,等等。与12世纪的西夏梵汉对音资料相比照,可以知道西夏与敦煌河西方音有明显的承续关系。 展开更多
关键词 敦煌文献 梵汉对音 河西方音
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Effect of Different Land Use Patterns on Physical Properties of Soil Water in Yellow River Wetland in Shaanxi Province 被引量:2
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作者 刘云鹏 张社奇 +1 位作者 谷洁 解迎革 《Agricultural Science & Technology》 CAS 2010年第9期148-152,共5页
[Objective] This study was to reveal the effect of different land use patterns on physical characteristics of soil water in the Yellow River wetland in Shaanxi Province.[Method]Taking Yellow River wetland in Shaanxi P... [Objective] This study was to reveal the effect of different land use patterns on physical characteristics of soil water in the Yellow River wetland in Shaanxi Province.[Method]Taking Yellow River wetland in Shaanxi Province as experimental plot,we compared the physical properties of the soil water under different land use patterns and studied the physical properties and the change law of soil water during the wetland degeneration process.[Result]Under different land use patterns,soil bulk density rose with the increase of soil depth.During the degeneration process of from river wetland to reclaimed wetland(paddy field),finally to abandoned land owing to salinization,the mean soil bulk density reduced correspondingly from 1.474 to 1.522 g/cm3,finally to 1.593 g/cm3 when abandoned.Accompanying wetland degeneration,soil became compact increasingly,and the indicators of soil porosity(total porosity,capillary porosity,non-capillary porosity)were also reduced with the change of land use patterns,in which,capillary porosity and total porosity reached the extremely significant level with the change of land use patterns,and non-capillary porosity reached significant level.The changes of soil porosity condition accelerated the deterioration of wetland.Under different land use patterns,the maximum soil moisture capacity,capillary moisture capacity and minimum moisture capacity all showed a similar change law.Compared with wetland,the maximum soil moisture capacity of reclaimed land(paddy field)and salinized land respectively decreased by 5.7% and 22.3%,capillary moisture capacity by 0.2% and 19.4%,minimum moisture capacity by 2.7% and 15.9%.Of the three land use patterns,wetland displayed both higher water holding capacity and water drainage capacity over reclaimed land(paddy field)and salinized land.By comparison with wetland,the reclaimed land(paddy field)and salinized land respectively decreased by 12.4% and 15.2% in total water holding capacity,and by 2.7% and 15.9% in total water drainage capacity.[Conclusion]To conserve the water resource in Yellow River wetland,regulate the hydrological cycle and enhance drought and water logging resistances,it should be noted that reasonable countermeasures be taken to exploit the state-owned forest land and paddy field around the wetland and the related resources. 展开更多
关键词 Yellow River wetland in Shaanxi Land use pattern Soil bulk density Water holding capacity Water drainage capacity
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子夏教衍西河地域考论 被引量:6
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作者 袁传璋 《安徽师范大学学报(社会科学版)》 2006年第6期674-681,共8页
论述了子夏对孔子的学术承传及其在中华学术史上的地位;辨析了郑玄、郦道元、司马贞、张守节诸家关于西河地域指认的谬误;考证了子夏系卫国人氏,其从孔子游当在夫子第四次访卫时起。子夏退教及归老的西河,在卫国故商墟王畿之内,而非如... 论述了子夏对孔子的学术承传及其在中华学术史上的地位;辨析了郑玄、郦道元、司马贞、张守节诸家关于西河地域指认的谬误;考证了子夏系卫国人氏,其从孔子游当在夫子第四次访卫时起。子夏退教及归老的西河,在卫国故商墟王畿之内,而非如郑玄所说的在河西“龙门至华阴之地”。 展开更多
关键词 子夏 六艺 章句义理 卫国 西河
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The Impact of Arid Climate Change on Agriculture of Dry Valley in Southwest China and Its Adaptive Countermeasures 被引量:7
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作者 鲍文 《Agricultural Science & Technology》 CAS 2011年第5期737-740,共4页
The eco-environmental vulnerability and underdevelopment of the agriculture in Southwest China would strengthen its disadvantage conditions further on the condition of arid climate change.It is necessary to deal with ... The eco-environmental vulnerability and underdevelopment of the agriculture in Southwest China would strengthen its disadvantage conditions further on the condition of arid climate change.It is necessary to deal with the relations between resource utilization and eco-environment finely and ascertain the adaptive principles on the dry valley agriculture to the arid climate change in order to change the extensive utilization of the special agricultural resources.The paper gave some adaptive countermeasures that develop modern rangeland husbandry,strengthening the special agriculture and agricultural industrialization,emphasis on the ecological agriculture development,constructing the extension system of water-saving modern agriculture,encouraging the service industry related to "agriculture,peasants and the countryside",constructing water utilization facilities,and exploiting the renewable energies. 展开更多
关键词 ARID Climate change Southwest China Dry valley AGRICULTURE Adaptive countermeasures.
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THE BALANCE BETWEEN SUPPLY AND DEMAND OF WATER RESOURCES AND THE WATER-SAVING POTENTIAL FOR AGRICULTURE IN THE HEXI CORRIDOR 被引量:9
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作者 GAOQian-zhao DUHu-lin 《Chinese Geographical Science》 SCIE CSCD 2002年第1期23-29,共7页
The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consump... The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consumption in development and utilization is 43. 33x 10~8m^3. Water supply and demand reach a balance on the recent level of production, but loss ofevaporation and evapotranspiration is as much as 25. 69 x 1010~8m^3. So net use efficiency of waterresources is 59% Based on analyzing balance between water and land considering ecologicalenvironment at present, there exists the serious water shortage in the Shiyang River system whereirrigation lands have overloaded. There is a comparative balance between supply and demand of waterresource in the Heihe River system; and the Sule River system has some surplus water to extendirrigation land. Use of agriculture water accounts for 83. 3% and ecological forest and grass for 6.9% . The Hexi Corridor still has a great potential for water saving in agriculture production.Water-saving efficiency of irrigation is about 10% by using such traditional technologies as furrowand border-dike irrigation and small check irrigation, and water-saving with plastic film cover andtechniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigatedwater. Incremental irrigation area for water-saving potential in the Hexi Corridor has beenestimated as 56% - 197% to original irrigation area. So the second water sources can be developedfrom water saving agriculture in the Hexi Corridor under Development of the Western Part of China inlarge scale. This potential can be realized step by step through developing the water-savingmeasures, improving the ecological condition of oasis agriculture, and optimizing allocation ofwater resources in three river systems. 展开更多
关键词 water resources balance between supply and demand water-saving potential ofagriculture hexi corridor
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Ice-wedge Pseudomorphs Showing Climatic Change Since the Late Pleistocene in the Source Area of the Yellow River, Northeast Tibet 被引量:3
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作者 CHENG Jie ZHANG Xujiao +4 位作者 TIAN Mingzhong YU Wenyang YU Jiangkuan TANG Dexiang YUE Jianwei 《Journal of Mountain Science》 SCIE CSCD 2005年第3期193-201,共9页
The source area of the Yellow River is located in the northeastern Tibetan Plateau, and is a high-elevation region with the annual mean temperature of -3.9℃. The ice-wedge pseudomorphs discovered in this region are r... The source area of the Yellow River is located in the northeastern Tibetan Plateau, and is a high-elevation region with the annual mean temperature of -3.9℃. The ice-wedge pseudomorphs discovered in this region are recognized as two types. One was found in sandy gravel beds of the second terrace of the Yellow River. This ice-wedge pseudomorph is characterized by higher ratio of breadth/depth, and are 1-1.4 m wide and about 1 m deep. The bottom border of the ice-wedge pseudomorph is round arc in section. Another discovered in the pedestal of the second terrace has lower ratio of width/depth, and is o.3-1.0 m wide and 1-2 m deep. Its bottom border is sharp. Based on the TL dating, the former was formed at the middleHolocene (5.69±0.43 ka BP and 5.43±0.41 ka BP), that is, the Megathermal, and the latter was formed at the late Last Glacial Maximum (13.49±1.43 ka BP). Additionally, the thawing-freezing folders discovered in the late Late Pleistocene proluvium are 39.83±3.84 ka BP in age. The study on the ice-wedge pseudomorphs showed that the air temperature was lowered by up to 6-7℃ in the source area of the Yellow River when the ice-wedge pseudomorphs and thawing-freezing folds developed. 展开更多
关键词 Ice-wedge pseudomorph PALEOCLIMATE Last Glacial Age MEGATHERMAL the source area of the Yellow River Tibetan Plateau
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HISTORICAL DESERTIFICATION PROCESS IN HEXI CORRIDOR,CHINA 被引量:3
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作者 WANG Nai-ang ZHANG Chun-hui LI Gang CHENG Hong-yi 《Chinese Geographical Science》 SCIE CSCD 2005年第3期245-253,共9页
Over the last 2000 years, approximately 38 ancient cities were abandoned through desertification in Hexi Corridor, Northwest China. Among them, 21.05% were abandoned during the Northern and Southern Dynasties, 21.05% ... Over the last 2000 years, approximately 38 ancient cities were abandoned through desertification in Hexi Corridor, Northwest China. Among them, 21.05% were abandoned during the Northern and Southern Dynasties, 21.05% during the end of the Tang Dynasty and the Five Dynasties, and 57.9% during the Ming and Qing dynasties. At the same time, main lakes were shrinking rapidly from the 5th Century to the 6th Century and the end of the Qing Dynasty. The climate in these periods was relatively arid and cold with frequent dusts. The phase of these changes indicated that there were three periods of desertification enlargement in the northern China. They were Northern and Southern Dynasties, the end of Tang Dynasty and Five Dynasties, the Ming and Qing dynasties. The macro-process of desertification in the study area was controlled mainly by the climatic changes. But from the facts that the population density in the middle of Qing Dynasty had exceeded the critical index of population pressure in arid area and the usage rate of water resources had exceeded 40% in Hexi Corridor, this paper also suggests that human activities have played an important role in desertification processes of the study area mainly during the recent 300 years. 展开更多
关键词 historical desertification climate change human activities Hexi Corridor
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Assessment of Heavy Metal Pollution in Estuarine Surface Sediments of Tangxi River in Chaohu Lake Basin 被引量:19
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作者 LI Ruzhong SHU Kun +1 位作者 LUO Yueying SHI Yong 《Chinese Geographical Science》 SCIE CSCD 2010年第1期9-17,共9页
A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor (EF) and geoaccumulation index (Igeo) as well as multivariate sta... A total of 30 surface sediments samples from the estuary wetland of the Tangxi River, Chaohu Lake Basin were obtained and tested. Enrichment factor (EF) and geoaccumulation index (Igeo) as well as multivariate statistical analysis methods including Factor Analysis (FA) and Hierarchical Cluster Analysis (HCA) were applied for the assessment of heavy metal pollution in surface sediments. The results of EF values show that the pollution of copper (Cu) and cadmium (Cd) occurs in the estuarine sediments, and that zinc (Zn), lead (Pb) and chrome (Cr) may originate from crustal materials or natural weathering process. The mean EF values of the five heavy metals are in the decreasing order: Cu〉Cd)Zn〉Pb〉Cr. Based on the lgeo of target heavy metals, the surface sediments collected from the study area can be approximately categorized as unpolluted with Zn, Pb and Cr, and moderately polluted with Cu and Cd. The degree of heavy metal pollution decreases in the order of Cu〉Cd〉Zn〉Pb〉Cr. Three groups of pollution factors are presented from FA: Zn-TOC, Cu-Cd and Cr-Pb, which respectively accounte for 27.22%, 25.20% and 21.05% of variance. By means of HCA, a total number of seven groups are distinguished from 30 sampling sites. Results indicate that Cu and Cd are the prior controlled pollutants in the estuarine sediments of the Tangxi River. 展开更多
关键词 heavy metal pollution SEDIMENT ESTUARY multivariate analysis Chaohu Lake Basin
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Variations of Laohugou Glacier No.12 in the western Qilian Mountains, China, from 1957 to 2015 被引量:14
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作者 LIU Yu-shuo QIN Xiang +4 位作者 CHEN Ji-zu LI Zhen-lin WANG Jing DU Wen-tao GUO Wan-qin 《Journal of Mountain Science》 SCIE CSCD 2018年第1期25-32,共8页
Glaciers were solid reservoirs and important water resources in western China,but they were retreating significantly in context of global warming.Laohugou Glacier No.12 was the largest valley glacier in Qilian Mountai... Glaciers were solid reservoirs and important water resources in western China,but they were retreating significantly in context of global warming.Laohugou Glacier No.12 was the largest valley glacier in Qilian Mountains.In this study,realtime kinematic(RTK)data,topographic map and World View-2 satellite imagery were used to measure changes in terminus,extent and volume of Laohugou Glacier No.12.Results showed that Laohugou Glacier No.12 was shrinking significantly since 1957.From1960 to 2015,the terminus reduction of Laohugou Glacier No.12 was 402.96 m(3.99%)in total,and glacier length decreased to 9.7 km from 10.1 km.Reduction of glacier area and volume were the most obvious.From 1957 to 2015,glacier area and volume decreased by 1.54 km^2(7.03%)and 0.1816 km^3,respectively.Reduction trend of terminus and area was slowing in 1950-1980s,even stable for a period in the mid-1980s,and then accelerated.Ice core analysis result and nearly meteorological station data shown an increasing trend of temperature in 1957-2015,it was a main reason of continuous retreating of Laohugou Glacier No.12. 展开更多
关键词 Glacier changes Laohugou Glacier No.12 Qilian Mountains Real-time kinematic Remote sensing image
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Livelihood Strategy Change and Land Use Change——Case of Danzam Village in Upper Dadu River Watershed,Tibetan Plateau of China 被引量:3
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作者 YAN Jianzhong ZHANG Yili +1 位作者 ZHANG Liping WU Yingying 《Chinese Geographical Science》 SCIE CSCD 2009年第3期231-240,共10页
Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population increase, has received more attention. However, case studies on how institution reforms af... Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population increase, has received more attention. However, case studies on how institution reforms affect farmers' livelihood strategies and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer, pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms, livelihood strategy of smallholders and land use change in rural China. 展开更多
关键词 livelihood strategy land use change agricultural involution upper Dadu River watershed Tibetan Plateau China
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SAFETY ANALYSIS OF WATER RESOURCES AND ECO-ENVIRONMENT IN SHIYANG RIVER BASIN 被引量:2
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作者 ZHANG Ji-shi ZHANG Yong-qiu +3 位作者 PU Rui-feng CHEN Ren-sheng CHENG Zhong-shan WANG Ming-quan 《Chinese Geographical Science》 SCIE CSCD 2005年第3期238-244,共7页
The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the... The research on the present situation of soil and water development and utilization in Shiyang River Basin shows that water resources and eco-environment situation in this area are near the edge of collapse. Since the water crises occurred in the 1970s, problems caused by continuous decrease of water resources have been becoming serious year by year and eco-environment crisis occurred as a consequence. Up to now, 10 380ha of irrigated lands have been abandoned due to sand coverage and water shortage in the basin. Ground water was over exploded in Wuwei and Minqin because of water shortage. Ground water table in many places dropped under 5m (which is the ecology water table level), thus about 3000ha ofElaeagnus angustifolia forest come to dead and another 5800ha become feeble, and wind-drift sand near the oasis become alive. According to the current situation, if water utilization scope was not enlarged, a water transfer volume of 600×10^6m^3/a from other areas will be suitable to keep water resources and eco-environment safety in the basin, and also 70×10^6m^3/a will be left as spare water. Under this condition the water resources and eco-environment of the basin can reach the critical safety line of 2.032×10^6m^3/a; or if 180×10^6m^3 of water can be transferred from other areas, the water resources can reach the safety warning line of 1.732×10^9m^3/a. 展开更多
关键词 water resources water resources safety Shiyang River Basin
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Effect of Using Magnetic Brackish Water on Irrigated Bell Pepper Crop (Capsicum annuum L.) Characteristics in Lower Jordan Valley/West Bank 被引量:5
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作者 Amer Marei Dia Rdaydeh +1 位作者 Dia Karajeh Nawaf Abu-Khalaf 《Journal of Agricultural Science and Technology(A)》 2014年第10期830-838,共9页
Increasing salinity of the groundwater is one of major challenges faced by agricultural sector in West Bank/Palestine. This study was carried out in the Lower Jordan Valley (LJV) under greenhouse field condition, wh... Increasing salinity of the groundwater is one of major challenges faced by agricultural sector in West Bank/Palestine. This study was carried out in the Lower Jordan Valley (LJV) under greenhouse field condition, where an area of 0.12 ha was irrigated with 3.5 dS/m magnetic treated water during the growing season 2012/2013. The results of this pilot project show that there are significant increases in the yield of red and yellow bell pepper of about 20% and 18% on fresh weight basis, respectively. Water use efficiency increased by 15% and an increase in shelf time of 7 d were also recorded. The chlorophyll content raised significantly in the leaves of treated plants compared to the controlled one by 2.5 mg/g. Bell pepper irrigated with magnetic water produces 37% more four champers than that of the controlled one. On the other hand, there were no clear significant effects on the height of the plant, number of fruits, distance between nods, size of fruits, number and thickness of walls and sugar contents. Applying visible/near infrared (VIS/N|R) spectroscopy test shows that it is possible to distinguish between treated and controlled bell pepper fruits. Multivariate data analysis (MVDA) method was used to test the classification of chemical elements in the fruit and it was found that treated and controlled fruit samples are divided into two groups according to their water treatment. An increase in all nutrient concentrations was found in fruits irrigated with magnetic treated water compared with the controlled one. Further testing is needed especially by involving other variables such as decreasing the volume of irrigated water and fertilizers. 展开更多
关键词 Magnetic water brackish groundwater bell pepper yield-quality shelf time Palestine.
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Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor, NW China Since the Last Interglacial 被引量:1
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作者 YANGTaibao YUYongtao +3 位作者 LIJijun ANCongrong LIUJinfeng ZHANGJunyan 《Journal of Mountain Science》 SCIE CSCD 2004年第2期128-142,共15页
Paleomagnetic determinations on lithological profiles of two paralleled[( )-275(long )]drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that ... Paleomagnetic determinations on lithological profiles of two paralleled[( )-275(long )]drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event ([(28.4)( )]kyr~[(25.8)( )]kyr), Laschamp Event ([(43.3)( )]kyr^40.5 kyr), Gaotai Event (82.8 kyr~[(72.4)25( )]kyr) and the Blake Event (127.4 kyr^113.3 kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1-H6)[(. )-250( )]Here,[( )-250( )]we tentatively[( )-250( )]propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earths magnetic field shifted between a temporal normal and a negative period, the earths magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earths incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions. 展开更多
关键词 PALEOMAGNETISM geomagnetic excursion the Late Pleistocene arid Northwestern China
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Spatio-temporal variability of periphytic protozoa related to environment in the Niyang River,Tibet,China 被引量:1
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作者 刘海平 叶少文 +6 位作者 杨学峰 郭传波 张惠娟 范丽卿 张良松 Sovan Lek 李钟杰 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第3期489-500,共12页
The Niyang River, a main tributary of the Yarlung Zangbo River, is an important and typical plateau fiver ecosystem in Tibet, China. At present, few studies have focused on its aquatic living resources and fiver ecolo... The Niyang River, a main tributary of the Yarlung Zangbo River, is an important and typical plateau fiver ecosystem in Tibet, China. At present, few studies have focused on its aquatic living resources and fiver ecology. In this study, the composition, abundance, and diversity of periphytic protozoa were investigated across four seasons from 2008 to 2009 to better understand their spatio-temporal patterns and relationship to the environment. Our investigation shows that periphytic protozoa in the Niyang River contained 15 genera, belonged to Tubulinea, Alveolata, Discosea and Rhizaria, Alveolata possessed most genera, up to nine, with highest share in abundance, exceeding 50%, Difflugia and Glaucoma were dominant genera. Moreover, four diversity indices of periphytic protozoa, including species richness, total abundance, Shannon-Wiener diversity index and Pielou's evenness index, displayed a significant descending trend as the seasons continued, in the order of winter, spring, summer and autumn; with a significant difference existing between winter and summer (or autumn) for Shannon-Wiener diversity index and species richness (P〈0.05). Four of these diversity indices also presented a V-shaped pattern between the upper middle course of the Niyang River and the confluence of the Niyang River and Yarlung Zangbo River, with the lowest value occurred in the middle course of the Niyang River. However, no significant variation was found through the Niyang River (P〉0.05). In addition, canonical correlation analysis (CCA) shows that the densities of Difflugia, Glaucomais, Enchelydium, Cyphoderia, and Enchelys correlate with water temperature, alkalinity, hardness, pH, and dissolved oxygen, respectively. Lastly, the relationship between periphytic protozoa diversity and the environmental factors of the Niyang River can be predicted using classification and regression trees (CART) annalysis, which suggests that the total abundance and Shannon-Wiener diversity index would be higher when the elevation is above 3 308 m. On the other hand, the Shannon-Wiener diversity index and Pielou's evenness index would be lower when pH and ammoniacal nitrogen have lower or higher values. Finally yet importantly, close attention should be paid to periphytic protozoa and its environment to ensure sustainable development of the Niyang River ecosystem. 展开更多
关键词 Tibetan Plateau Niyang River periphytic protozoa ENVIRONMENT spatio-temporal dynamic
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Characteristics and Driving Forces of Spatial Expansion of Oasis Cities and Towns in Hexi Corridor, Gansu Province, China 被引量:3
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作者 LIU Hailong SHI Peiji +5 位作者 TONG Huali ZHU Guofeng LIU Haimeng ZHANG Xuebin WEI Wei WANG Xinmin 《Chinese Geographical Science》 SCIE CSCD 2015年第2期250-262,共13页
This paper presents an integrated study of urban spatial expansion in the Hexi Corridor, Gansu Province, China based on TM, ETM remote sensing data in 1987, 1990, 1995, 2000, 2006 and 2011. The study explores the char... This paper presents an integrated study of urban spatial expansion in the Hexi Corridor, Gansu Province, China based on TM, ETM remote sensing data in 1987, 1990, 1995, 2000, 2006 and 2011. The study explores the characteristics of urban spatial expansion and dynamic mechanism by using expansion speed index, expansion intensity index, compact index, fractal dimension, and extended flexibility index. We built the index system of influencing factors of urban spatial expansion by using the grey incidence model. The results showed that urban spatial expansion rate in the Hexi Corridor has been on the upward trend since 1987. Expansion intensity showed an obvious upward trend, however, the upward trend varied in different urban areas. In addition, the urban structure was loose relatively, but the urban compactness was more obvious. The urban spatial form tended to be simple, and the urban land use tended to become more intensive. Urban spatial expansion experienced several stages: padding internally, external expansion and padding internally. The main driving factors of urban spatial expansion are not the urban water resources and the oasis scale, but one or several factors such as economy, traffic, population, resource and national policy. 展开更多
关键词 spatial expansion driving forces oasis cities and towns Hexi Corridor China
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Partitioning of grain-size components of estuarine sediments and implications for sediment transport in southwestern Laizhou Bay, China 被引量:13
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作者 陈广泉 易亮 +4 位作者 陈沈良 黄海军 刘艳霞 徐勇航 曹建荣 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2013年第4期895-906,共12页
Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sedime... Sediment transport in estuarine systems has been of increasing interest for scientists during the past few decades. However, the mechanisms for sediment redistribution remain unclear. We characterized in detail sediment transport in the Xiaoqing River estuary using the mathematical Weibull function to partition grain-size components of surface sediments in the southwestern Laizhou Bay, Northeast China. Four partitioned components: finer than 4,4.6-12.5, 23.4-63.3, and 67.1-132.6 μm were interpreted in terms of hydrodynamic conditions. During sediment transport, silt grains were suspended and moved seaward from three depositional centers, whereas fine-grained sands moved generally landward. Overall, sediments are transported clockwise in a generally NNE direction near shore and then turn eastward offshore. The mathematical partitioning method showed a great potential for future estuarine environmental studies. 展开更多
关键词 sediment transport estuarine environment sediment grain size mathematical partitioning Laizhou Bay (China)
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On sustainable development of agriculture in oasis: a case study of Hexi Corridor, Gansu, China 被引量:1
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作者 Wang Limin 《Ecological Economy》 2007年第2期179-189,共11页
Hexi Corridor is one of the most potential areas in the China’s Western Development in 21st century. However, the problems - the sustainable development of oasis agriculture, the ecosystem of the oasis edge, the land... Hexi Corridor is one of the most potential areas in the China’s Western Development in 21st century. However, the problems - the sustainable development of oasis agriculture, the ecosystem of the oasis edge, the landscape structure, the population density in oasis, water resources and land resources in oasis are deteriorating and have restricted the sustainable development of society and economy in this area. This paper summarizes the problems at present, and puts forward the concept of protecting and constructing the oasis environment and sustainable development for the sustainable development of the oasis agriculture in the Hexi Corridor. 展开更多
关键词 Hexi Corridor OASIS Sustainable agriculture Development PROBLEM
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