[Objective] The aim was to learn the soil nutrient status of the main rapeseed planting areas in Linxiang County,Yunnan Province,and propose full production potential of soil and fertilizer recommendations,thereby pro...[Objective] The aim was to learn the soil nutrient status of the main rapeseed planting areas in Linxiang County,Yunnan Province,and propose full production potential of soil and fertilizer recommendations,thereby promoting local rapeseed production and income.[Method] The soil samples collected in field and tested in laboratory,with amount of fertilizer needed by rapeseed investigation were combined to calculate the formulated fertilization.[Result] Most of the soil organic matter and nutrient content of NPK were at the middle or higher level in the main rapeseed planting areas in Linxiang County.However,more than half of the soils were acidic or strongly acidic,and the soil p H maintained below 5.5.The shortage soil boron was more serious,the average content and nearly 60% of the sample of soil available boron were less than 0.5 mg/kg.[Conclusion] The formulated fertilization recommendations were identified as follows.To achieve the goal of 3 750 kg/hm^2240,150 and 75 kg/ha,if the application amount of manure was 15 000 kg/h,the total fertilizer N,P2O5,K2 O amount applied were separately 300,195 and 195 kg/hm^2.The chemical fertilizer N,P2O5,K2 O amount applied should be respectively 240,150 and 75 kg/hm^2,if the application amount of manure was 15 000 kg/hm^2.The nitrogen species of urea(containing N 46%),causing weakest effect on soil acidification,was selected and applied about with 525 kg/hm^2.The alkaline calcium magnesium phosphate(P2O520%),alternating superphosphate,was applied with about 750 kg/hm^2.Sulfuric acid potassium(K2O 50%) was applied with about 150 kg/hm^2.About 7.5kg/hm^2 borax was applied into soil as basal fertilizer,while spraying 7.5 kg/hm^2 fluid boron at the Bolting stag.展开更多
[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated ...[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated area in the oasis, was studied and nine influential factors were chosen through grey relation analysis. [Result] According to grey relation analysis, top five factors influencing water produc- tivity of maize during 1995-2009 were as follows: applied quantity of chemical fertil- izers〉labour input〉seeds〉mulch amount〉pesticide amount, which indicated that controllable factors, instead of uncontrollable ones, dominate in influence of water productivity of maize in oasis in arid areas. [Conclusion] With water resource limited, investment of controllable factors in high-efficient agricultural production should be the major strategy to improve water productivity of maize in oasis of arid areas.展开更多
Soil degradation, including rocky desertification,of the karst regions in China is severe. Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded. Understa...Soil degradation, including rocky desertification,of the karst regions in China is severe. Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded. Understanding the balance between soil formation and soil erosion is critical for long-term soil sustainability, yet little is known about the initial soil forming processes on karst terrain. Herein we examine the initial weathering processes of several types of carbonate bedrock containing varying amounts of non-carbonate minerals in the SPECTRA Critical Zone Observatory, Guizhou Province, Southwest China. We compared the weathering mechanisms of the bedrock to the mass transfer of mineral nutrients in a soil profile developed on these rocks and found that soil formation and nutrient contents are strongly dependent upon the weathering of interbedded layers of more silicate-rich bedrock(marls). Atmospheric inputs from dust were also detected.展开更多
Focusing on sustainability of water resources and ecology in the complex karst critical zone, we illustrated functions of the hydro-geochemical analysis on hydrology from the aspects of connection and interaction amon...Focusing on sustainability of water resources and ecology in the complex karst critical zone, we illustrated functions of the hydro-geochemical analysis on hydrology from the aspects of connection and interaction among hydrology–vegetation–soils/rock fractures along the karst subsurface profile. We reviewed isotopic and geochemical interpretations on tracing water sources for plant uptake, quantifying watershed outlet flow composition and residence times, and evaluating long-term evolution among climate–landscape–hydrology in the karst critical zone. In this paper, the application of the hydro-geochemical analysis on the above aspects in the karst areas of southwest China was summarized.展开更多
The near-surface environment of the Tibetan Plateau is a fragile critical zone. Our understanding of the transport and transformation of persistent organic pollutants(POPs) in the ecosystem has significantly improved ...The near-surface environment of the Tibetan Plateau is a fragile critical zone. Our understanding of the transport and transformation of persistent organic pollutants(POPs) in the ecosystem has significantly improved with research conducted in recent decades. In the current study,POP concentrations in soils logarithmically decreased and fractionated with increasing distance from the source area,patterns attributed to air–soil exchange. Transport from soils resulted in the enrichment of POP concentrations in plants and sediments. The enantiomeric fraction indicated that transformation of POPs in soils was significantly correlated with altitude. At the same time, the chiral signature of POPs in soils was maintained from soils to sediments, while the chiral transformation from soils to plants was found to be complex.展开更多
The concept of the imperfection sensitive region is given. The advanced stochastic imperfection method is used to research the imperfection sensitive region of single-layer latticed domes. Taking a K6 single-layer lat...The concept of the imperfection sensitive region is given. The advanced stochastic imperfection method is used to research the imperfection sensitive region of single-layer latticed domes. Taking a K6 single-layer latticed dome with a diameter of 50 m as an example, its imperfection sensitive region is made up of the first 12 kinds of joints. The influence of the imperfections of support joints on the stability of the K6 single-layer latticed dome is negligible. Influences of the joint imperfections of the main rib and the secondary rib on the structural stability are similar. The initial deviations of these joints all greatly lower the critical load of the dome. Results show that the method can analyze the structural imperfection sensitive region quantitatively and accurately.展开更多
The purpose of this study was focused on the imaging features of the chest trauma and its relation to clinical characteristics. All the injured patients were from the Yushu Earthquake areas on days April 14 - 23,2010....The purpose of this study was focused on the imaging features of the chest trauma and its relation to clinical characteristics. All the injured patients were from the Yushu Earthquake areas on days April 14 - 23,2010. After an initial treatment,the injurers were rapidly transported from Yushu at an altitude of 4 000 m via air to Xining at 2 260 m within 6~8 h,and promptly admitted to Qinghai Provincial People’s Hospital. A total of 130 wounded injurers who had high suspicion of chest injuries all had examinations of Chest X-ray and computed tomography(CT)images. Of them 63 injurers presented at least one of the features of the chest trauma in imaging with a positive rate of 48.5 %. Of these,37 cases (28.5 %) were multi-system with multiple injuries ,33 cases (25.4 %) were chest trauma with multi-injury types,which included thoracic fractures in 54 cases (85.7 %),pleural injury in 56 cases (88.9 %),lung injury in 54 cases (85.7 %),lungs complications in 37 cases (58.7 %),and extrapulmonary complications of 35 cases (55.6 %). The radiological data were analyzed retrospectively. The features of chest trauma in Yushu Earthquake,the complications of chest injuries,and the relation between imaging findings and clinical manifestations,as well as the differences of chest trauma between Yushu Earthquake and Wenchuan Earthquake were discussed in detail.展开更多
One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwa...One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwater table. The central impediment to quantifying this component of the subsurface is the difficulty associated with direct observations. Here, we report solute chemistry as a function of depth collected over a full year across the shale-derived vadose zone of the Eel River Critical Zone Observatory using a set of novel sub-horizontal wellbores,referred to as the vadose zone monitoring system. The results of this first geochemical glimpse into the deep vadose zone indicate a dynamic temporal and depth-resolved structure. Major cation concentrations reflect seasonal changes in precipitation and water saturation, and normalized ratios span the full range of values reported for the world's largest rivers.展开更多
Abstract: The Wenchuan earthquake generated strong surface disturbances and triggered a large number of loose deposits, resulting in the disaster- prone environment with special watershed hydrological characteristics...Abstract: The Wenchuan earthquake generated strong surface disturbances and triggered a large number of loose deposits, resulting in the disaster- prone environment with special watershed hydrological characteristics. This paper was to propose a debris flow formation process and explore the permeability characteristics and critical hydrodynamic conditions of the loose deposits triggered by the earthquake. The Guo Juanyan gully (31005'27" N to 31005'46" N, 103036'58" E to 103037'09" E) in Du Jiangyan City, located in the meizoseismal areas of the Wenchuan earthquake, was chosen as the study area and the disaster-prone environment was analyzed. The formation process of the debris flow was first proposed using a stability analysis, and then, the permeability characteristics of loose deposits were determined via in situ permeability experiments. Finally, the critical 1 h rainfall was simulated through a distributed hydrological model and verified by field observations. The formation process of debris flow could be divided into three stages based on the relationship between the hydrodynamic force and loose deposit resistance. The critical 1 h rainfall amounts under three antecedent moisture conditions (I-dry, Ⅱ-normal and Ⅲ-wet) were 52 mm/h, 43 mm/h and 34 mm/h, respectively. This study proposed a debris flow formation process in the meizoseismal areas of the Wenchuan earthquake based on the stability analysis and defined the rainfall threshold for debris flow early warning at the local level, which is significant for debris flow mitigation and risk management.展开更多
The carbon pool stored in soil carbonate is comparable to the soil organic carbon.Therefore,secondary calcite precipitation in supersaturated catchment could be an important,yet poorly constrained,carbon sink within t...The carbon pool stored in soil carbonate is comparable to the soil organic carbon.Therefore,secondary calcite precipitation in supersaturated catchment could be an important,yet poorly constrained,carbon sink within the modern global carbon cycle.The chemical analysis of some dissolved species transported by rivers,such as elevated Sr/Ca and Mg/Ca ratios but also heavy stable Ca isotopic compositions,witness the formation of secondary calcite in rivers draining arid regions.However,in areas affected by active tectonics and rapid physical erosion,co-variations in the fluvial Sr/Ca and Mg/Ca ratios could also be related to incongruent carbonate weathering processes.Here,we present a model to assess the roles played by incongruent carbonate dissolution and secondary calcite precipitation in modern weathering processes.We tested and applied the model to rivers draining the Himalayan–Tibetan region.The results suggest that regional aridity in the drainage basin promotes carbon sequestration as secondary carbonate but that for a given runoff,incongruent dissolution of carbonate possibly related to rapid physical erosion amplifies such sequestration.The isotopic compositions(^(13)C/^(12)C and^(18)O/^(16)O)of detrital carbonate transported by the main rivers in South and South-East Tibet imply that around 1%of the suspended material transported by those rivers corresponds to secondary carbonate and can represent between 5%and 15%of the alkalinity flux.Most of these alkalinity transported as particulate material is,nevertheless related to the weathering of carbonate lithologies and is also subjected to dissolution prior its final storage in sedimentary basins.However,on glacial-interglacial timescale this will amplify the significant role of mountain weathering on climatic variations.展开更多
According to the rock burst features occurred in the coal mass of roadway rib in one mine,the mechanics model of coal mass and roof structure system along the edge of goaf was founded to analyze the stress of roof roc...According to the rock burst features occurred in the coal mass of roadway rib in one mine,the mechanics model of coal mass and roof structure system along the edge of goaf was founded to analyze the stress of roof rock layer,so the subside curve of roof rock layer was deduced.Furthermore,the stability of coal and rock system were analyzed,the critical load and critical resistance zone were used to judge the danger degree of rock burst occurrence.The influence of coal mass strength,brittleness degree,coal seam thickness,roof thickness,suspending length,equivalent shear module on the critical load, critical resistance zone was confirmed.So the rock burst occurrence conditions of coal mass in roadway rib mainly depend on mining depth,coal seam thickness and hard roof and floor,which are decided by the above studies,and successfully applied in prediction and prevention of rock burst in this mine.展开更多
OBJECTIVE The objective of this study was to explore the effect of CDA-2, a selective inhibitor of abnormal methylation enzymes in cancer cells, on the therapeutic efficacy of cytotoxic chemotherapy. METHODS Advanced ...OBJECTIVE The objective of this study was to explore the effect of CDA-2, a selective inhibitor of abnormal methylation enzymes in cancer cells, on the therapeutic efficacy of cytotoxic chemotherapy. METHODS Advanced cancer patients, all of whom had previously undergone chemotherapy, were randomly divided into 2 groups, one receiving chemotherapy only as the control group, and the other receiving CDA-2 in addition to chemotherapy as the combination group. The therapeutic efficacies and the toxic maniestations of the 2 groups were compared based on the WHO criteria. RESULTS Of 454 cancer patients enrolled in phase Ⅲ clinical trials of CDA-2, 80, 188, and 186 were breast cancer, NSCLC, and primary hepatoma patients, respectively. Among them 378 patients completed treatments according to the protocols. The results showed that the overall effective rate of the combination group was 2.6 fold that of the control group, 4.8 fold in the case of breast cancer, 2.3 fold in the case of primary hepatoma, and 2.2 fold in the case of NSCLC. Surprisingly, the combination therapy appeared to work better for stage Ⅳ than stage Ⅲ patients. CDA-2 did not contribute additional toxicity. On the contrary, it reduced toxic manifestations of chemotherapy, particularly regarding white blood cells, nausea and vomiting. CONCLUSION Modulation of abnormal methylation enzymes by CDA-2 is definitely helpful to supplement chemotherapy. It significantly increased the therapeutic efficacy and reduced the toxic manifestation of cytotoxic chemotherapy on breast cancer and NSCLC.展开更多
This thesis tries to explore the problems of the rural English teachers' professional development and aims to give some hints on teachers' professional development and future teacher training. This thesis makes a su...This thesis tries to explore the problems of the rural English teachers' professional development and aims to give some hints on teachers' professional development and future teacher training. This thesis makes a survey to 20 rural English teachers from 10 primary schools in the surrounding areas of Linyi City. The survey mainly focuses on the following four aspects: basic situation of the teachers, knowledge of English language and teaching skills, teachers' motivation, and self-analysis of their development. With an analysis of the results of the investigation, the author wants to evoke teachers' and researchers' awareness for improving English language teachers' professional development in rural primary schools展开更多
In this paper, the electron temperature gradient (ETG) instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full ...In this paper, the electron temperature gradient (ETG) instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full electron kinetics is considered and the behaviours of the modes and the transport in the parameter regimes close to the instability threshold are emphasized. The fitting formulas of the critical gradient, for negative magnetic shear, are given.展开更多
We compute the mass and temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient a2 〈 0 in anti-de Sitter space and perform the stability analysis of topological black holes. When k = -1...We compute the mass and temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient a2 〈 0 in anti-de Sitter space and perform the stability analysis of topological black holes. When k = -1, the third order Lovelock black holes are thermodynamically stable for the whole range r+. When k = 1, we found that the black hole has an intermediate unstable phase for D = 7. In eight dimensional spacetimes, however, a new phase of thermodynamically unstable small black holes appears if the coefficient a is under a critical value. For D ≥ 9, black holes have similar the distributions of thermodynamically stable regions to the case where the coefficient & is under a critical value for D = 8. It is worth to mention that all the thermodynamic and conserved quantities of the black holes with fiat horizon do not depend on the Loveloek coefficients and are the same as those of black holes in general gravity.展开更多
基金The National Key Technology R&D Program(2012BAD40B02)~~
文摘[Objective] The aim was to learn the soil nutrient status of the main rapeseed planting areas in Linxiang County,Yunnan Province,and propose full production potential of soil and fertilizer recommendations,thereby promoting local rapeseed production and income.[Method] The soil samples collected in field and tested in laboratory,with amount of fertilizer needed by rapeseed investigation were combined to calculate the formulated fertilization.[Result] Most of the soil organic matter and nutrient content of NPK were at the middle or higher level in the main rapeseed planting areas in Linxiang County.However,more than half of the soils were acidic or strongly acidic,and the soil p H maintained below 5.5.The shortage soil boron was more serious,the average content and nearly 60% of the sample of soil available boron were less than 0.5 mg/kg.[Conclusion] The formulated fertilization recommendations were identified as follows.To achieve the goal of 3 750 kg/hm^2240,150 and 75 kg/ha,if the application amount of manure was 15 000 kg/h,the total fertilizer N,P2O5,K2 O amount applied were separately 300,195 and 195 kg/hm^2.The chemical fertilizer N,P2O5,K2 O amount applied should be respectively 240,150 and 75 kg/hm^2,if the application amount of manure was 15 000 kg/hm^2.The nitrogen species of urea(containing N 46%),causing weakest effect on soil acidification,was selected and applied about with 525 kg/hm^2.The alkaline calcium magnesium phosphate(P2O520%),alternating superphosphate,was applied with about 750 kg/hm^2.Sulfuric acid potassium(K2O 50%) was applied with about 150 kg/hm^2.About 7.5kg/hm^2 borax was applied into soil as basal fertilizer,while spraying 7.5 kg/hm^2 fluid boron at the Bolting stag.
基金Supported by National Natural Science Foundation of China(41161082)Gansu Natural Science Foundation(1107RJZA167)~~
文摘[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated area in the oasis, was studied and nine influential factors were chosen through grey relation analysis. [Result] According to grey relation analysis, top five factors influencing water produc- tivity of maize during 1995-2009 were as follows: applied quantity of chemical fertil- izers〉labour input〉seeds〉mulch amount〉pesticide amount, which indicated that controllable factors, instead of uncontrollable ones, dominate in influence of water productivity of maize in oasis in arid areas. [Conclusion] With water resource limited, investment of controllable factors in high-efficient agricultural production should be the major strategy to improve water productivity of maize in oasis of arid areas.
基金supported by the National Environmental Research Council of the UK(Grant Nos.NE/N007530/1 and NE/N007603/1)the National Science Foundation of China(Grant No.41571130042)
文摘Soil degradation, including rocky desertification,of the karst regions in China is severe. Karst landscapes are especially sensitive to soil degradation as carbonate rocks are nutrient-poor and easily eroded. Understanding the balance between soil formation and soil erosion is critical for long-term soil sustainability, yet little is known about the initial soil forming processes on karst terrain. Herein we examine the initial weathering processes of several types of carbonate bedrock containing varying amounts of non-carbonate minerals in the SPECTRA Critical Zone Observatory, Guizhou Province, Southwest China. We compared the weathering mechanisms of the bedrock to the mass transfer of mineral nutrients in a soil profile developed on these rocks and found that soil formation and nutrient contents are strongly dependent upon the weathering of interbedded layers of more silicate-rich bedrock(marls). Atmospheric inputs from dust were also detected.
基金supported by the National Natural Scientific Foundation of China(No.41571130071)
文摘Focusing on sustainability of water resources and ecology in the complex karst critical zone, we illustrated functions of the hydro-geochemical analysis on hydrology from the aspects of connection and interaction among hydrology–vegetation–soils/rock fractures along the karst subsurface profile. We reviewed isotopic and geochemical interpretations on tracing water sources for plant uptake, quantifying watershed outlet flow composition and residence times, and evaluating long-term evolution among climate–landscape–hydrology in the karst critical zone. In this paper, the application of the hydro-geochemical analysis on the above aspects in the karst areas of southwest China was summarized.
基金financially supported by the Fundamental Research Funds for the Central Universities(2652014003,2652016073)State Key Laboratory of Biogeology and Environmental Geology(GBL2135,GBL21405)
文摘The near-surface environment of the Tibetan Plateau is a fragile critical zone. Our understanding of the transport and transformation of persistent organic pollutants(POPs) in the ecosystem has significantly improved with research conducted in recent decades. In the current study,POP concentrations in soils logarithmically decreased and fractionated with increasing distance from the source area,patterns attributed to air–soil exchange. Transport from soils resulted in the enrichment of POP concentrations in plants and sediments. The enantiomeric fraction indicated that transformation of POPs in soils was significantly correlated with altitude. At the same time, the chiral signature of POPs in soils was maintained from soils to sediments, while the chiral transformation from soils to plants was found to be complex.
文摘The concept of the imperfection sensitive region is given. The advanced stochastic imperfection method is used to research the imperfection sensitive region of single-layer latticed domes. Taking a K6 single-layer latticed dome with a diameter of 50 m as an example, its imperfection sensitive region is made up of the first 12 kinds of joints. The influence of the imperfections of support joints on the stability of the K6 single-layer latticed dome is negligible. Influences of the joint imperfections of the main rib and the secondary rib on the structural stability are similar. The initial deviations of these joints all greatly lower the critical load of the dome. Results show that the method can analyze the structural imperfection sensitive region quantitatively and accurately.
基金Project of Qinghai Development of Science and Technology (No.2011-N-150)
文摘The purpose of this study was focused on the imaging features of the chest trauma and its relation to clinical characteristics. All the injured patients were from the Yushu Earthquake areas on days April 14 - 23,2010. After an initial treatment,the injurers were rapidly transported from Yushu at an altitude of 4 000 m via air to Xining at 2 260 m within 6~8 h,and promptly admitted to Qinghai Provincial People’s Hospital. A total of 130 wounded injurers who had high suspicion of chest injuries all had examinations of Chest X-ray and computed tomography(CT)images. Of them 63 injurers presented at least one of the features of the chest trauma in imaging with a positive rate of 48.5 %. Of these,37 cases (28.5 %) were multi-system with multiple injuries ,33 cases (25.4 %) were chest trauma with multi-injury types,which included thoracic fractures in 54 cases (85.7 %),pleural injury in 56 cases (88.9 %),lung injury in 54 cases (85.7 %),lungs complications in 37 cases (58.7 %),and extrapulmonary complications of 35 cases (55.6 %). The radiological data were analyzed retrospectively. The features of chest trauma in Yushu Earthquake,the complications of chest injuries,and the relation between imaging findings and clinical manifestations,as well as the differences of chest trauma between Yushu Earthquake and Wenchuan Earthquake were discussed in detail.
基金supported by the US National Science Foundation,Project EAR-1331904 for the Eel River Critical Zone Observatory
文摘One of the greatest challenges in critical zone studies is to document the moisture dynamics, water flux,and solute chemistry of the unsaturated, fractured and weathered bedrock that lies between the soil and groundwater table. The central impediment to quantifying this component of the subsurface is the difficulty associated with direct observations. Here, we report solute chemistry as a function of depth collected over a full year across the shale-derived vadose zone of the Eel River Critical Zone Observatory using a set of novel sub-horizontal wellbores,referred to as the vadose zone monitoring system. The results of this first geochemical glimpse into the deep vadose zone indicate a dynamic temporal and depth-resolved structure. Major cation concentrations reflect seasonal changes in precipitation and water saturation, and normalized ratios span the full range of values reported for the world's largest rivers.
基金Financial support was provided by the international cooperation project of the Ministry of Science and Technology (Grant No.2013DFA21720)the Key Laboratory of Mountain Hazards and Earth Surface Processes independent project fundingthe National Natural Science Foundation (Grant No. 41372331)
文摘Abstract: The Wenchuan earthquake generated strong surface disturbances and triggered a large number of loose deposits, resulting in the disaster- prone environment with special watershed hydrological characteristics. This paper was to propose a debris flow formation process and explore the permeability characteristics and critical hydrodynamic conditions of the loose deposits triggered by the earthquake. The Guo Juanyan gully (31005'27" N to 31005'46" N, 103036'58" E to 103037'09" E) in Du Jiangyan City, located in the meizoseismal areas of the Wenchuan earthquake, was chosen as the study area and the disaster-prone environment was analyzed. The formation process of the debris flow was first proposed using a stability analysis, and then, the permeability characteristics of loose deposits were determined via in situ permeability experiments. Finally, the critical 1 h rainfall was simulated through a distributed hydrological model and verified by field observations. The formation process of debris flow could be divided into three stages based on the relationship between the hydrodynamic force and loose deposit resistance. The critical 1 h rainfall amounts under three antecedent moisture conditions (I-dry, Ⅱ-normal and Ⅲ-wet) were 52 mm/h, 43 mm/h and 34 mm/h, respectively. This study proposed a debris flow formation process in the meizoseismal areas of the Wenchuan earthquake based on the stability analysis and defined the rainfall threshold for debris flow early warning at the local level, which is significant for debris flow mitigation and risk management.
文摘The carbon pool stored in soil carbonate is comparable to the soil organic carbon.Therefore,secondary calcite precipitation in supersaturated catchment could be an important,yet poorly constrained,carbon sink within the modern global carbon cycle.The chemical analysis of some dissolved species transported by rivers,such as elevated Sr/Ca and Mg/Ca ratios but also heavy stable Ca isotopic compositions,witness the formation of secondary calcite in rivers draining arid regions.However,in areas affected by active tectonics and rapid physical erosion,co-variations in the fluvial Sr/Ca and Mg/Ca ratios could also be related to incongruent carbonate weathering processes.Here,we present a model to assess the roles played by incongruent carbonate dissolution and secondary calcite precipitation in modern weathering processes.We tested and applied the model to rivers draining the Himalayan–Tibetan region.The results suggest that regional aridity in the drainage basin promotes carbon sequestration as secondary carbonate but that for a given runoff,incongruent dissolution of carbonate possibly related to rapid physical erosion amplifies such sequestration.The isotopic compositions(^(13)C/^(12)C and^(18)O/^(16)O)of detrital carbonate transported by the main rivers in South and South-East Tibet imply that around 1%of the suspended material transported by those rivers corresponds to secondary carbonate and can represent between 5%and 15%of the alkalinity flux.Most of these alkalinity transported as particulate material is,nevertheless related to the weathering of carbonate lithologies and is also subjected to dissolution prior its final storage in sedimentary basins.However,on glacial-interglacial timescale this will amplify the significant role of mountain weathering on climatic variations.
基金the Natural Science Fund of Liaoning Province(20042176)
文摘According to the rock burst features occurred in the coal mass of roadway rib in one mine,the mechanics model of coal mass and roof structure system along the edge of goaf was founded to analyze the stress of roof rock layer,so the subside curve of roof rock layer was deduced.Furthermore,the stability of coal and rock system were analyzed,the critical load and critical resistance zone were used to judge the danger degree of rock burst occurrence.The influence of coal mass strength,brittleness degree,coal seam thickness,roof thickness,suspending length,equivalent shear module on the critical load, critical resistance zone was confirmed.So the rock burst occurrence conditions of coal mass in roadway rib mainly depend on mining depth,coal seam thickness and hard roof and floor,which are decided by the above studies,and successfully applied in prediction and prevention of rock burst in this mine.
文摘OBJECTIVE The objective of this study was to explore the effect of CDA-2, a selective inhibitor of abnormal methylation enzymes in cancer cells, on the therapeutic efficacy of cytotoxic chemotherapy. METHODS Advanced cancer patients, all of whom had previously undergone chemotherapy, were randomly divided into 2 groups, one receiving chemotherapy only as the control group, and the other receiving CDA-2 in addition to chemotherapy as the combination group. The therapeutic efficacies and the toxic maniestations of the 2 groups were compared based on the WHO criteria. RESULTS Of 454 cancer patients enrolled in phase Ⅲ clinical trials of CDA-2, 80, 188, and 186 were breast cancer, NSCLC, and primary hepatoma patients, respectively. Among them 378 patients completed treatments according to the protocols. The results showed that the overall effective rate of the combination group was 2.6 fold that of the control group, 4.8 fold in the case of breast cancer, 2.3 fold in the case of primary hepatoma, and 2.2 fold in the case of NSCLC. Surprisingly, the combination therapy appeared to work better for stage Ⅳ than stage Ⅲ patients. CDA-2 did not contribute additional toxicity. On the contrary, it reduced toxic manifestations of chemotherapy, particularly regarding white blood cells, nausea and vomiting. CONCLUSION Modulation of abnormal methylation enzymes by CDA-2 is definitely helpful to supplement chemotherapy. It significantly increased the therapeutic efficacy and reduced the toxic manifestation of cytotoxic chemotherapy on breast cancer and NSCLC.
文摘This thesis tries to explore the problems of the rural English teachers' professional development and aims to give some hints on teachers' professional development and future teacher training. This thesis makes a survey to 20 rural English teachers from 10 primary schools in the surrounding areas of Linyi City. The survey mainly focuses on the following four aspects: basic situation of the teachers, knowledge of English language and teaching skills, teachers' motivation, and self-analysis of their development. With an analysis of the results of the investigation, the author wants to evoke teachers' and researchers' awareness for improving English language teachers' professional development in rural primary schools
基金Supported by the National Natural Science Foundation of China(10135020)
文摘In this paper, the electron temperature gradient (ETG) instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full electron kinetics is considered and the behaviours of the modes and the transport in the parameter regimes close to the instability threshold are emphasized. The fitting formulas of the critical gradient, for negative magnetic shear, are given.
文摘We compute the mass and temperature of third order Lovelock black holes with negative Gauss-Bonnet coefficient a2 〈 0 in anti-de Sitter space and perform the stability analysis of topological black holes. When k = -1, the third order Lovelock black holes are thermodynamically stable for the whole range r+. When k = 1, we found that the black hole has an intermediate unstable phase for D = 7. In eight dimensional spacetimes, however, a new phase of thermodynamically unstable small black holes appears if the coefficient a is under a critical value. For D ≥ 9, black holes have similar the distributions of thermodynamically stable regions to the case where the coefficient & is under a critical value for D = 8. It is worth to mention that all the thermodynamic and conserved quantities of the black holes with fiat horizon do not depend on the Loveloek coefficients and are the same as those of black holes in general gravity.