The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only a...The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only as a good age indicator for the geomorphic surfaces but also coats themselves can be directly used as dating materials in the ESR method. Through measuring the thickness of carbonate coats on stones in soils on the alluvial terraces in the mouth of the Heishanxia gorge of the Yellow River and ESR dating of layers separated from the carbonate coats, the average of accumulation rates of the thickness of carbonate coats on stones since 1.57 Ma was calculated to be 0.10 mm/ka in the studied area, and a regression equation between carbonate coat thickness and age was also generated. From these research results, ages of T2-T11 terraces of the Yellow River in the studied area were systematically determined, and their values are in turn 18 ka, 94 ka, 139 ka, 215 ka, 305 ka, 410 ka, 495 ka, 742 ka,展开更多
The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the wo...The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.展开更多
Because of the construction o f the Three Gorge Project (TGP), the local turbulent flow, compared to the original, h as been changed greatly. In order to analyze the variation of hydrodynamic feat ure in detail, a 3-D...Because of the construction o f the Three Gorge Project (TGP), the local turbulent flow, compared to the original, h as been changed greatly. In order to analyze the variation of hydrodynamic feat ure in detail, a 3-D mathematical model was established to simulate the turbule nt flow in the corresponding area. The results of computation indicate that grea t changes of flow took placed in the area close to the cofferdam, but the area i s not large. The results are in agreement with that of the obtained.展开更多
The transformation of dilapidated houses in rural areas is not only a livelihood project related to the broad masses of rural people,but also a major project to win the battle against poverty. Luquan Yi and Miao Auton...The transformation of dilapidated houses in rural areas is not only a livelihood project related to the broad masses of rural people,but also a major project to win the battle against poverty. Luquan Yi and Miao Autonomous County,Yunnan Province,located in the high mountain and gorge area along Jinsha River,is one of the key counties of poverty alleviation and development with a wide range of poverty and a deep degree of poverty. The incidence of poverty is 22. 21%. Housing security is the focus,difficulty and emphasis of poverty alleviation in this county,the number of dilapidated houses is large,the type is complex,the transformation is difficult,and the implementation cost is high.Since the beginning of 2017,Luquan County has faced difficulties,explored in depth,pioneered and innovated,and completed the renovation of 54 801 dilapidated houses in an all-round way. It created a road full of characteristics and effectiveness of rural dilapidated housing transformation,and explored a set of effective scientific identification and accurate transformation models for rural dilapidated housing worthy of reference and promotion. Successful renovation of dilapidated houses,combined with industrial poverty alleviation,education poverty alleviation,health poverty alleviation and other accurate poverty alleviation measures,have made Luquan County win a decisive victory in the fight against poverty. By the end of December 2018,the incidence of poverty in the county had dropped to 0. 54%,and 115 poor villages( including 83 extremely poor villages) had successfully shaken off poverty. This paper analyzes and summarizes the concrete methods,main effects,characteristics and bright spots,successful experience,and reference significance of the scientific identification and precise transformation mode of rural dilapidated houses in this county,so as to provide a necessary reference for the transformation of rural dilapidated houses in Yunnan Province and even poor counties in similar provinces( cities and districts).展开更多
A series of gorges on the lower reaches of the Yarlung Zangbo River is like an enormous crevice splitting the southeastern Qinghai-Xizang (Tibet)Plateau to create a passage through which warm, wet air flow from the In...A series of gorges on the lower reaches of the Yarlung Zangbo River is like an enormous crevice splitting the southeastern Qinghai-Xizang (Tibet)Plateau to create a passage through which warm, wet air flow from the Indian Ocean reaches the inner part of the plateau. This moisture passage was mainly strengthened after the Pleistocene epoch in the Quaternary period and has played a major role in affecting the beginning date of the rainy season and the amount of the plateau’s rainfall. It has also served as a corridor for the living things on the southern and the northern sides of the Himalayas to mingle with each other. The region along this passage is abundant in evidences of species of differentiation, variation and biological division. Also the passage has provided a favorable environment for human beings and affected natural phenomena there.展开更多
The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China,...The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20—40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 878, 725 and 117 times of inside cycling coefficients of N, P and K, respectively. 3392, 1026 and 1588 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 1431, 132 and 1048 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 549%, 130%, and 834% of N, P and K withdraw from leaves to branches, 499%, 199% and 730% of N, P and K withdraw from branches to trunks per year, respectively.展开更多
The energies of three forest ecosystems in the Three Gorge Reservoir area were analyzed. The results showed that the existing energies were 151 2438, 139 2014 and 175 1659 (×10 10 J/hm 2), the annual ne...The energies of three forest ecosystems in the Three Gorge Reservoir area were analyzed. The results showed that the existing energies were 151 2438, 139 2014 and 175 1659 (×10 10 J/hm 2), the annual net fixed energies were 38 8924, 31 2214 and 46 8231 (×10 10 J/hm 2), and the utilization efficiency of light energies were 1 16, 0 99 and 1 40 for the Quercus acutissima forest(Q.A.), the Pinus massoniana forest (P.M.), and the Queresus acutissima and Pinus massoniana mixed forest (Q.P.), respectively. In the Three Gorge Reservoir Area, the energy efficiency of Quercus acutissima and Pinus massoniana mixed forest is the best.展开更多
Based on field landscape investigations, thermoluminescence （TL）, magnetostratigraphy and Ioess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 M...Based on field landscape investigations, thermoluminescence （TL）, magnetostratigraphy and Ioess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift （from Sanmen Gorge to Mengjin） and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression （from Mengjin to Kouma）. All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period. Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles. However, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.展开更多
The northern and northeastern parts of the Iraqi exhibit different types of gorges. Some of them are few kilometers in length and few hundred meters in height. The most significant gorge is the Gulley Ali Bed gorge in...The northern and northeastern parts of the Iraqi exhibit different types of gorges. Some of them are few kilometers in length and few hundred meters in height. The most significant gorge is the Gulley Ali Bed gorge in Rawandooz area;its length is about 12.1 Km, with maximum and minimum widths of 100 to 155 m, respectively. The water in the gorge flows in two opposite directions, from the north and south through two streams;they meet in the middle of the gorge, and then change the streams direction towards west;for few kilometers before it merges in the Greater Zab River. The gorge runs within very hard thickly bedded to massive carbonate rocks, which belong to Sarmord, Qamchuqa and Bekhme formations (Cretaceous in age). To the right of the southern entrance;stands Korak anticline, whereas to the left occurs Peris anticline. To the right of the northern entrance;stands Handreen anticline, whereas to the left is Bradost anticline;represented by Balikian Mountain. The gorge is developed by continuous lateral and vertical growth of the four mentioned anticlines, with continuous incision of both streams, Rawandooz from the north and Khlaifan from the south. Both shifted their courses, continuously as indicated from the presence of many wind gaps in the aforementioned anticlines.展开更多
Based on contour tillage of wide ridge and furrow covering and agro-forestry, this paper sets up a compound ridge culture mode in hillside orchards and introduces a long-term observation to the mode＇s effects on ecol...Based on contour tillage of wide ridge and furrow covering and agro-forestry, this paper sets up a compound ridge culture mode in hillside orchards and introduces a long-term observation to the mode＇s effects on ecological benefits of water and soil conservation. A five-year study shows that compound ridge culture in hillside orchards is effective in water and soil conservation, especially in reducing soil erosion. Compared with the traditional management modes of orchards, compound ridge culture has reduced runoff amount by 41.96%-57.96%, soil erosion amount by 55.47%-67.75%. Compound ridge culture also brings an obvious reduction of soil nutrient loss and of non-point source pollution, which is of great importance for keeping and increasing the productivity of hillside orchards in the Three Gorge Reservoir Area.展开更多
基金This work was supportedby the National Natural Science Foundation of China (Grant No. 49732095)Joint Foundation of Earthquake Science (Grant Nos. 197021 and 9507422)and the State Major Basic Research Development Plan (Grant No. 95130102).
文摘The calcium carbonate coats on stones developed in soil on the geomorphic surfaces of coarse clastic sediments in arid-semiarid regions contain evident information of age. The thickness of coats can be used not only as a good age indicator for the geomorphic surfaces but also coats themselves can be directly used as dating materials in the ESR method. Through measuring the thickness of carbonate coats on stones in soils on the alluvial terraces in the mouth of the Heishanxia gorge of the Yellow River and ESR dating of layers separated from the carbonate coats, the average of accumulation rates of the thickness of carbonate coats on stones since 1.57 Ma was calculated to be 0.10 mm/ka in the studied area, and a regression equation between carbonate coat thickness and age was also generated. From these research results, ages of T2-T11 terraces of the Yellow River in the studied area were systematically determined, and their values are in turn 18 ka, 94 ka, 139 ka, 215 ka, 305 ka, 410 ka, 495 ka, 742 ka,
文摘The proposed hydroelectric project on the Yangtze Gorges will be one of the largest power stations in the world.The problem of induced seismicity to the project has attracted much attention throughout China and the world.A research program has been carried out by the State Seismological Bureau of China.Based on the size of the reservoir and the lithology,geological structure,permeability,stress state,and previous seismicity in the region,the potential risk of reservoir-induced seismicity has been estimated.The results suggest that,after impoundment in the reservoir area,the possibility of induced seismicity cannot be completely ruled out.The areas with potential risk may be in some gorges composed of karstified carbonate and plutonic granite around the dam site.However,the magnitude is expected to be limited owing to the small dimension of the induced seismogenic faults.
文摘Because of the construction o f the Three Gorge Project (TGP), the local turbulent flow, compared to the original, h as been changed greatly. In order to analyze the variation of hydrodynamic feat ure in detail, a 3-D mathematical model was established to simulate the turbule nt flow in the corresponding area. The results of computation indicate that grea t changes of flow took placed in the area close to the cofferdam, but the area i s not large. The results are in agreement with that of the obtained.
基金Supported by Project Commissioned by the Office of Rural Work Leading Group of Kunming Municipal Committee of the Communist Party of ChinaConstruction Project of Party Branch Secretary of"Double Leader"Teachers in Colleges and Universities of the Ministry of Education of China
文摘The transformation of dilapidated houses in rural areas is not only a livelihood project related to the broad masses of rural people,but also a major project to win the battle against poverty. Luquan Yi and Miao Autonomous County,Yunnan Province,located in the high mountain and gorge area along Jinsha River,is one of the key counties of poverty alleviation and development with a wide range of poverty and a deep degree of poverty. The incidence of poverty is 22. 21%. Housing security is the focus,difficulty and emphasis of poverty alleviation in this county,the number of dilapidated houses is large,the type is complex,the transformation is difficult,and the implementation cost is high.Since the beginning of 2017,Luquan County has faced difficulties,explored in depth,pioneered and innovated,and completed the renovation of 54 801 dilapidated houses in an all-round way. It created a road full of characteristics and effectiveness of rural dilapidated housing transformation,and explored a set of effective scientific identification and accurate transformation models for rural dilapidated housing worthy of reference and promotion. Successful renovation of dilapidated houses,combined with industrial poverty alleviation,education poverty alleviation,health poverty alleviation and other accurate poverty alleviation measures,have made Luquan County win a decisive victory in the fight against poverty. By the end of December 2018,the incidence of poverty in the county had dropped to 0. 54%,and 115 poor villages( including 83 extremely poor villages) had successfully shaken off poverty. This paper analyzes and summarizes the concrete methods,main effects,characteristics and bright spots,successful experience,and reference significance of the scientific identification and precise transformation mode of rural dilapidated houses in this county,so as to provide a necessary reference for the transformation of rural dilapidated houses in Yunnan Province and even poor counties in similar provinces( cities and districts).
文摘A series of gorges on the lower reaches of the Yarlung Zangbo River is like an enormous crevice splitting the southeastern Qinghai-Xizang (Tibet)Plateau to create a passage through which warm, wet air flow from the Indian Ocean reaches the inner part of the plateau. This moisture passage was mainly strengthened after the Pleistocene epoch in the Quaternary period and has played a major role in affecting the beginning date of the rainy season and the amount of the plateau’s rainfall. It has also served as a corridor for the living things on the southern and the northern sides of the Himalayas to mingle with each other. The region along this passage is abundant in evidences of species of differentiation, variation and biological division. Also the passage has provided a favorable environment for human beings and affected natural phenomena there.
文摘The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20—40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 878, 725 and 117 times of inside cycling coefficients of N, P and K, respectively. 3392, 1026 and 1588 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 1431, 132 and 1048 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 549%, 130%, and 834% of N, P and K withdraw from leaves to branches, 499%, 199% and 730% of N, P and K withdraw from branches to trunks per year, respectively.
文摘The energies of three forest ecosystems in the Three Gorge Reservoir area were analyzed. The results showed that the existing energies were 151 2438, 139 2014 and 175 1659 (×10 10 J/hm 2), the annual net fixed energies were 38 8924, 31 2214 and 46 8231 (×10 10 J/hm 2), and the utilization efficiency of light energies were 1 16, 0 99 and 1 40 for the Quercus acutissima forest(Q.A.), the Pinus massoniana forest (P.M.), and the Queresus acutissima and Pinus massoniana mixed forest (Q.P.), respectively. In the Three Gorge Reservoir Area, the energy efficiency of Quercus acutissima and Pinus massoniana mixed forest is the best.
基金Science and Technology Planning Project of Yunnan Province,No.2007D199MNational Natural Science Foundation of China,No.40462002No.40161002
文摘Based on field landscape investigations, thermoluminescence （TL）, magnetostratigraphy and Ioess-paleosol sequence, we found that there are at least four Yellow River terraces, whose ages are 0.86 Ma, 0.62 Ma, 0.13 Ma and 0.05 Ma, in Yuxi Fault-Uplift （from Sanmen Gorge to Mengjin） and at least three Yellow River terraces, whose ages are 1.24 Ma, 0.25 Ma and 0.05 Ma, in Huabei Fault Depression （from Mengjin to Kouma）. All the terraces have a similar structure that several meters of paleosols directly develop on the top of fluvial silt. It shows that the Yellow River incised and consequently abandoned floodplain converted to terrace during the interglacial period. Therefore, there may be a link between the formation of terraces and glacial-interglacial climatic cycles. However, the differences in the Yellow River terrace sequences and ages between Yuxi Fault-Uplift and Huabei Fault Depression indicate that the surface uplift should play an important role in the formation of these terraces.
文摘The northern and northeastern parts of the Iraqi exhibit different types of gorges. Some of them are few kilometers in length and few hundred meters in height. The most significant gorge is the Gulley Ali Bed gorge in Rawandooz area;its length is about 12.1 Km, with maximum and minimum widths of 100 to 155 m, respectively. The water in the gorge flows in two opposite directions, from the north and south through two streams;they meet in the middle of the gorge, and then change the streams direction towards west;for few kilometers before it merges in the Greater Zab River. The gorge runs within very hard thickly bedded to massive carbonate rocks, which belong to Sarmord, Qamchuqa and Bekhme formations (Cretaceous in age). To the right of the southern entrance;stands Korak anticline, whereas to the left occurs Peris anticline. To the right of the northern entrance;stands Handreen anticline, whereas to the left is Bradost anticline;represented by Balikian Mountain. The gorge is developed by continuous lateral and vertical growth of the four mentioned anticlines, with continuous incision of both streams, Rawandooz from the north and Khlaifan from the south. Both shifted their courses, continuously as indicated from the presence of many wind gaps in the aforementioned anticlines.
基金the Western Action Project of Chinese Acad-emy of Sciences(KZCX2-XB2-07)the Item of State Council Three Gorge Project Construction Committee Executive Office(SX2001-021).
文摘Based on contour tillage of wide ridge and furrow covering and agro-forestry, this paper sets up a compound ridge culture mode in hillside orchards and introduces a long-term observation to the mode＇s effects on ecological benefits of water and soil conservation. A five-year study shows that compound ridge culture in hillside orchards is effective in water and soil conservation, especially in reducing soil erosion. Compared with the traditional management modes of orchards, compound ridge culture has reduced runoff amount by 41.96%-57.96%, soil erosion amount by 55.47%-67.75%. Compound ridge culture also brings an obvious reduction of soil nutrient loss and of non-point source pollution, which is of great importance for keeping and increasing the productivity of hillside orchards in the Three Gorge Reservoir Area.
