Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-Apr...Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-April)was studied to reveal the variations of the key factors at different explosive-developing stages.This EC had weak low-level baroclinicity,mid-level cyclonic-vorticity advection,and strong low-level water vapor convergence at the initial explosive-developing stage.The low-level baroclinicity and mid-level cyclonic-vorticity advection increased substantially during the maximum-deepening-rate stage.The diagnostic analyses using the Zwack-Okossi equation showed that diabatic heating was the main contributor to the initial rapid intensification of this EC.The cyclonic-vorticity advection and warm-air advection enhanced rapidly in the middle and upper troposphere and contributed to the maximum rapid intensification,whereas the diabatic heating weakened slightly in the mid-low troposphere.The relative contribution of the diabatic heating decreased from the initial explosive-developing stage to the maximum-deepening-rate stage due to the enhancement of other factors(the cyclonic-vorticity advection and warm-air advection).Furthermore,the physical factors contributing to this EC varied with the explosive-developing stage.The non-key factors at the initial explosive-developing stage need attention to forecast the rapid intensification.展开更多
The formulation of agricultural extension policy and the development of rural regional economy present the relationship of mutual existence,mutual influence and mutual promotion.Therefore,it is necessary to study the ...The formulation of agricultural extension policy and the development of rural regional economy present the relationship of mutual existence,mutual influence and mutual promotion.Therefore,it is necessary to study the agricultural extension policy according to the current situation of rural regional development.Agricultural technology extension system is an organization set up at county and township levels to provide farmers with scientific research achievements and practical technical services on planting,animal husbandry,fishery,forestry,agricultural machinery and water conservancy,and it is an important carrier for implementing the strategy of developing agriculture through science and technology.On the basis of expounding the value and significance of rural regional economic development,this paper analyzes the problems existing in China s rural regional development from the aspects of rural infrastructure and public services,rural labor force s cultural and scientific level,rural grass-roots extension system,etc.,and puts forward corresponding measures against the problems.This study has certain theoretical reference value for promoting the all-round development of China s rural economy and realizing the great strategy of rural revitalization in China.展开更多
The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 1...The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 170 Ma, following the Triassic collision between the Sino-Korean and Yangtze cratons. The framework that controls the present spatial distribution of UHP and HP metamorphic rocks in particular displays the typical features of a Cordilleran-type metamorphic core complex, in which at least four regional-scale, shallow-dipping detachment zones are recognized. Each of these detachment zones corresponds to a pressure gap of 0.5 to 2.0 GPa. The detachment zones separate the rocks exposed in the region into several petrotectonic units with different P-T conditions. The geometry and kinematics of both the detachment zones and the petrotectonic units show that the exhumation of UHP and HP metamorphic rocks in the Dabie-Sulu region was achieved, at least in part, by non-coaxial ductile flow in the multi-layered detachment zones, and by coaxial vertical shortening and horizontal stretching in the metamorphic units, under amphibolite- to greenschist-facies conditions, and in an extensional regime. All ductile extensional deformations occurred at depths below 10 to 15 km, i.e. below the brittle/ductile deformation transition.展开更多
Eddy characteristics derived from different data resources are compared: sea surface temperature(SST), sea surface height anomaly(SSHA) and surface drifter trajectories. The comparison suggests that the eddy stat...Eddy characteristics derived from different data resources are compared: sea surface temperature(SST), sea surface height anomaly(SSHA) and surface drifter trajectories. The comparison suggests that the eddy statistical characteristics are different using different variables to delineate eddies, but they show the similar trend. Based on the comparison, abnormal eddies with warm(cold) cores but counter-clockwise(clockwise) rotation are found in the Kuroshio Extension region.展开更多
The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 5...The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 545-kmlong active-source ocean bottom seismometer(OBS)wide-angle reflection/refraction profile in the East China Sea.The P wave velocity model shows that the Moho depth rises significantly,from approximately 30 km in the East China Sea shelf to approximately 16 km in the axis of the Okinawa Trough.The lower crustal high-velocity zone(HVZ)in the southern Okinawa Trough,with V_(p) of 6.8-7.3 km/s,is a remarkable manifestation of the mantle material upwelling and accretion to the lower crust.This confirms that the lower crustal high-velocity mantle accretion is developed in the southern Okinawa Trough.During the process of back-arc extension,the crustal structure of the southern Okinawa Trough is completely invaded and penetrated by the upper mantle material in the axis region.In some areas of the southern central graben,the crust may has broken up and entered the initial stage of seafloor spreading.The discontinuous HVZs in the lower crust in the back-arc region also indicate the migration of spreading centers in the back-arc region since the Cenozoic.The asthenosphere material upwelling in the continent-ocean transition zone is constantly driving the lithosphere eastward for episodic extension,and is causing evident tectonic migration in the Western Pacific back-arc region.展开更多
A large number of new varieties, especially hybrid rice, have been developed and released in China since 1998. The yield potential and grain quality of hybrid rice have also been improved significantly both for three-...A large number of new varieties, especially hybrid rice, have been developed and released in China since 1998. The yield potential and grain quality of hybrid rice have also been improved significantly both for three-line and two-line hybrid rice including indica and japonica types as well. The trends on extension of rice varieties in China since 1986 has been marked by the increasing number of new varieties, decreasing annual planting area per variety, decreasing number of varieties with a large-scale extension area, while both the renewal rate and the proportion of core varieties with cross-provincial extension have remained unchanged. This current major problems and future goals of rice breeding and extension in China were also discussed.展开更多
Based on the resent research about the planting structure of slope farmland in northern Shaanxi,in order to increase the native's income,we use the theory of the extension methods to analyze the planting structure...Based on the resent research about the planting structure of slope farmland in northern Shaanxi,in order to increase the native's income,we use the theory of the extension methods to analyze the planting structure of slope farmland,so that we can get the extensive strategy,and put them into use for planting of slope farmland to make the native's income higher.展开更多
On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN...On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da'an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.展开更多
Background:Visceral leishmaniasis(VL)was one of the most important parasitic diseases in China,caused by Leishmania protozoans and transmitted by sand flies.Recently VL cases have reappeared in China,including the ext...Background:Visceral leishmaniasis(VL)was one of the most important parasitic diseases in China,caused by Leishmania protozoans and transmitted by sand flies.Recently VL cases have reappeared in China,including the extension region of the Loess Plateau.The purpose of this study was to collect fundamental data on the host-vector VL system in the Loess Plateau to assist in the development of prevention and control measures.Methods:Sand flies were collected by light traps from rural areas in Shanxian,Henan,China in 2015,as well as in Wuxiang and Yangquan,Shanxi,China in 2017.The blood sources of sand flies were analyzed by PCR detecting the host-specific mitochondrial cytochrome b(mtDNA cyt b)gene fragments.Leishmania infection in sand flies was detected by amplifying and sequencing ribosomal DNA internal transcribed spacer 1(ITS1).The Leishmania specific antibodies in the sera of local dogs were detected by ELISA kit.Results:Blood sources showed diversity in the extension region of the Loess Plateau,including human,chicken,dog,cattle,pig and goat.Multiple blood sources within a sand fly were observed in samples from Yangquan(17/118,14.4%)and Wuxiang(12/108,11.1%).Leishmania DNA was detected in sand flies collected from Yangquan with minimum infection rate of 1.00%.The ITS1 sequences were conserved with the Leishmania donowni complex.The positive rate of Leishmania specific antibodies in dogs was 5.97%.Conclusions:This study detected the blood sources and Leishmania parasites infection of sand flies by molecular methods in the extension region of Loess Plateau,China.A high epidemic risk of leishmaniasis is currently indicated by the results as the infection of Leishmania in sand flies,the extensive blood sources of sand flies including humans,and positive antibody of Leishmania in local dog sera.Given the recent increase of VL cases,asymptomatic patients,dogs and other potential infected animals should be screened and treated.Furthermore,the density of sand flies needs to be controlled and personal protection should be strengthened.展开更多
Based on the analysis of a large number of core samples, logging results, logging interpretation data and dynamic data in the study area, the characteristics of Chang 6 reservoir in Zhouguan area of Baihe area are stu...Based on the analysis of a large number of core samples, logging results, logging interpretation data and dynamic data in the study area, the characteristics of Chang 6 reservoir in Zhouguan area of Baihe area are studied, and the favorable reservoir areas in the study area are predicted. The results show that the lithology of Chang 6 reservoir is mainly light gray and gray fine-grained to very fine-grained feldspar lithic sandstone. The pore types are mainly residual intergranular pores and feldspar dissolved pores, including debris dissolved pores and microfractures. The porosity and permeability values are low, which belongs to low porosity-low permeability and ultra-low permeability reservoirs. According to the reservoir distribution characteristics and related data, the Chang 6 reservoir in the study area is divided into two types, mainly Class II and Class III reservoirs. The comprehensive evaluation predicts that the spatial distribution of the favorable area of Chang 6 reservoir is not uniform, but the distribution area is large, which has broad exploration and development value, and provides the necessary conditions for the distribution study of the favorable oil-bearing zone in this area and the preparation for the next exploration and development.展开更多
基金jointly funded by the State Key Program of the National Natural Science Foundation of China(No.42130605)the Major Program of the National Natural Science Foundation of China(No.72293604)+5 种基金the Youth Innovative Talents Program of Guangdong Colleges and Universities(No.2022KQNCX026)the Natural Science Foundation of Shandong(No.ZR2022MD038)the Project of Enhancing School with Innovation of Guangdong Ocean University(No.230419106)the State Key Program of the National Natural Science Foundation of China(No.42130605)the National Natural Science Foundation of China(Nos.42275001,42276019,42205014,and 42275017)the Guangdong Ocean University Ph.D.Scientific Research Program(No.R19045).
文摘Explosive cyclones(ECs)occur frequently over the Kuroshio/Kuroshio Extension region.The most rapidly intensified EC over the Kuroshio/Kuroshio Extension region during the 42 years(1979-2020)of cold seasons(October-April)was studied to reveal the variations of the key factors at different explosive-developing stages.This EC had weak low-level baroclinicity,mid-level cyclonic-vorticity advection,and strong low-level water vapor convergence at the initial explosive-developing stage.The low-level baroclinicity and mid-level cyclonic-vorticity advection increased substantially during the maximum-deepening-rate stage.The diagnostic analyses using the Zwack-Okossi equation showed that diabatic heating was the main contributor to the initial rapid intensification of this EC.The cyclonic-vorticity advection and warm-air advection enhanced rapidly in the middle and upper troposphere and contributed to the maximum rapid intensification,whereas the diabatic heating weakened slightly in the mid-low troposphere.The relative contribution of the diabatic heating decreased from the initial explosive-developing stage to the maximum-deepening-rate stage due to the enhancement of other factors(the cyclonic-vorticity advection and warm-air advection).Furthermore,the physical factors contributing to this EC varied with the explosive-developing stage.The non-key factors at the initial explosive-developing stage need attention to forecast the rapid intensification.
文摘The formulation of agricultural extension policy and the development of rural regional economy present the relationship of mutual existence,mutual influence and mutual promotion.Therefore,it is necessary to study the agricultural extension policy according to the current situation of rural regional development.Agricultural technology extension system is an organization set up at county and township levels to provide farmers with scientific research achievements and practical technical services on planting,animal husbandry,fishery,forestry,agricultural machinery and water conservancy,and it is an important carrier for implementing the strategy of developing agriculture through science and technology.On the basis of expounding the value and significance of rural regional economic development,this paper analyzes the problems existing in China s rural regional development from the aspects of rural infrastructure and public services,rural labor force s cultural and scientific level,rural grass-roots extension system,etc.,and puts forward corresponding measures against the problems.This study has certain theoretical reference value for promoting the all-round development of China s rural economy and realizing the great strategy of rural revitalization in China.
基金This study was supported by the Key State Basic Research Development Project grant G1999075506the National Natural Science Foundation of China grants 49794041,49972067 and 49772146the former Ministry of Geology and Mineral Resources Project No.9501102.
文摘The present-day observable tectonic framework of the ultrahigh-pressure (UHP) and high-pressure (HP) metamorphic belts in the Dabie-Sulu region was dominantly formed by an extensional process, mostly between 200 and 170 Ma, following the Triassic collision between the Sino-Korean and Yangtze cratons. The framework that controls the present spatial distribution of UHP and HP metamorphic rocks in particular displays the typical features of a Cordilleran-type metamorphic core complex, in which at least four regional-scale, shallow-dipping detachment zones are recognized. Each of these detachment zones corresponds to a pressure gap of 0.5 to 2.0 GPa. The detachment zones separate the rocks exposed in the region into several petrotectonic units with different P-T conditions. The geometry and kinematics of both the detachment zones and the petrotectonic units show that the exhumation of UHP and HP metamorphic rocks in the Dabie-Sulu region was achieved, at least in part, by non-coaxial ductile flow in the multi-layered detachment zones, and by coaxial vertical shortening and horizontal stretching in the metamorphic units, under amphibolite- to greenschist-facies conditions, and in an extensional regime. All ductile extensional deformations occurred at depths below 10 to 15 km, i.e. below the brittle/ductile deformation transition.
基金The National Natural Science Foundation of China under contract Nos 41476022,41490643 and 41476158the Jiangsu Province Science Foundation for Youths under contract No.BK20150897+3 种基金the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology under contract Nos 2013r121 and 2014r072the National Basic Research Program(973 Program)of China under contract No.2014CB745000the National Program on Global Change and Air-Sea Interaction under contract Nos GASI-03-IPOVAI-05 and GASI-IPOVAI-04the State Key Laboratory of Tropical Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences under contract No.LTO1407
文摘Eddy characteristics derived from different data resources are compared: sea surface temperature(SST), sea surface height anomaly(SSHA) and surface drifter trajectories. The comparison suggests that the eddy statistical characteristics are different using different variables to delineate eddies, but they show the similar trend. Based on the comparison, abnormal eddies with warm(cold) cores but counter-clockwise(clockwise) rotation are found in the Kuroshio Extension region.
基金supported by the National Key Basic Research Program of China(Grant No.2013CB429701)the National Natural Science Foundation of China(Grant Nos.41606083,91958210,41606050 and 41210005)+1 种基金AoShan Technological Innovation Projects of National Laboratory for Marine Science and Technology(Qingdao)(2015ASKJ03)National Marine Geological Special Project(DD20190236,DD20190365,DD20190377)。
文摘The marginal sea and back-arc basins in the Western Pacific Ocean have become the focus of tectonics due to their unique tectonic location.To understand the deep crustal structure in the back-arc region,we present a 545-kmlong active-source ocean bottom seismometer(OBS)wide-angle reflection/refraction profile in the East China Sea.The P wave velocity model shows that the Moho depth rises significantly,from approximately 30 km in the East China Sea shelf to approximately 16 km in the axis of the Okinawa Trough.The lower crustal high-velocity zone(HVZ)in the southern Okinawa Trough,with V_(p) of 6.8-7.3 km/s,is a remarkable manifestation of the mantle material upwelling and accretion to the lower crust.This confirms that the lower crustal high-velocity mantle accretion is developed in the southern Okinawa Trough.During the process of back-arc extension,the crustal structure of the southern Okinawa Trough is completely invaded and penetrated by the upper mantle material in the axis region.In some areas of the southern central graben,the crust may has broken up and entered the initial stage of seafloor spreading.The discontinuous HVZs in the lower crust in the back-arc region also indicate the migration of spreading centers in the back-arc region since the Cenozoic.The asthenosphere material upwelling in the continent-ocean transition zone is constantly driving the lithosphere eastward for episodic extension,and is causing evident tectonic migration in the Western Pacific back-arc region.
文摘A large number of new varieties, especially hybrid rice, have been developed and released in China since 1998. The yield potential and grain quality of hybrid rice have also been improved significantly both for three-line and two-line hybrid rice including indica and japonica types as well. The trends on extension of rice varieties in China since 1986 has been marked by the increasing number of new varieties, decreasing annual planting area per variety, decreasing number of varieties with a large-scale extension area, while both the renewal rate and the proportion of core varieties with cross-provincial extension have remained unchanged. This current major problems and future goals of rice breeding and extension in China were also discussed.
基金Supported by The Special Research Projects of Education Department of Shaanxi Province (09JK556)The Special Fund-susten-tation Project of Key Disciplines of Shaanxi Province~~
文摘Based on the resent research about the planting structure of slope farmland in northern Shaanxi,in order to increase the native's income,we use the theory of the extension methods to analyze the planting structure of slope farmland,so that we can get the extensive strategy,and put them into use for planting of slope farmland to make the native's income higher.
基金Under the auspices of National Natural Science Foundation of China (No. 40572170, 40871088 )
文摘On the basis of the soil environment investigation in Da'an City, Jilin Province, China, 40 soil samples from main land use types were obtained and tested by standard method. Soil organic matter (SOM), total N (TN), total P (TP), total K (TK), available N (AN), available P (AP) and available K (AK) were chosen as the evaluation factors. A regional soil nutrient evaluation model was developed based on the matter-element model. The results show that the soil samples with nutrient grade Ⅱ-Ⅴ respectively account for 10%, 30%, 32.5% and 27.5%, and those with grade Ⅳ and Ⅴ account for 60% in all samples. The relationship between soil nutrients and land types indicates that the nutrients of farmland are relatively good, with 41.7% of soil samples with the nutrient grade Ⅳ and Ⅴ. The nutrients of saline-alkali land and sandy land are the worst, with 100% of soil samples with the nutrient grade IV and V. And the ratios of soil samples grade IV and V in grassland and wasteland are respectively 62.5 % and 54.55%. Generally speaking, the soil nutrients status in Da'an City is poor, 60% of soil samples are in poor and extremely poor conditions, indicating that the soil has been severely eroded. Being a relatively superior evaluation method with more accurate resuits and spatial distribution consistency, matter-element analysis is more suitable for regional soil nutrient evaluation than previous models.
基金This work was supported by National Natural Sciences Foundation of China(No.31970445&81371848)Shanxi Province Science and Technology Department(201803D31205).
文摘Background:Visceral leishmaniasis(VL)was one of the most important parasitic diseases in China,caused by Leishmania protozoans and transmitted by sand flies.Recently VL cases have reappeared in China,including the extension region of the Loess Plateau.The purpose of this study was to collect fundamental data on the host-vector VL system in the Loess Plateau to assist in the development of prevention and control measures.Methods:Sand flies were collected by light traps from rural areas in Shanxian,Henan,China in 2015,as well as in Wuxiang and Yangquan,Shanxi,China in 2017.The blood sources of sand flies were analyzed by PCR detecting the host-specific mitochondrial cytochrome b(mtDNA cyt b)gene fragments.Leishmania infection in sand flies was detected by amplifying and sequencing ribosomal DNA internal transcribed spacer 1(ITS1).The Leishmania specific antibodies in the sera of local dogs were detected by ELISA kit.Results:Blood sources showed diversity in the extension region of the Loess Plateau,including human,chicken,dog,cattle,pig and goat.Multiple blood sources within a sand fly were observed in samples from Yangquan(17/118,14.4%)and Wuxiang(12/108,11.1%).Leishmania DNA was detected in sand flies collected from Yangquan with minimum infection rate of 1.00%.The ITS1 sequences were conserved with the Leishmania donowni complex.The positive rate of Leishmania specific antibodies in dogs was 5.97%.Conclusions:This study detected the blood sources and Leishmania parasites infection of sand flies by molecular methods in the extension region of Loess Plateau,China.A high epidemic risk of leishmaniasis is currently indicated by the results as the infection of Leishmania in sand flies,the extensive blood sources of sand flies including humans,and positive antibody of Leishmania in local dog sera.Given the recent increase of VL cases,asymptomatic patients,dogs and other potential infected animals should be screened and treated.Furthermore,the density of sand flies needs to be controlled and personal protection should be strengthened.
文摘Based on the analysis of a large number of core samples, logging results, logging interpretation data and dynamic data in the study area, the characteristics of Chang 6 reservoir in Zhouguan area of Baihe area are studied, and the favorable reservoir areas in the study area are predicted. The results show that the lithology of Chang 6 reservoir is mainly light gray and gray fine-grained to very fine-grained feldspar lithic sandstone. The pore types are mainly residual intergranular pores and feldspar dissolved pores, including debris dissolved pores and microfractures. The porosity and permeability values are low, which belongs to low porosity-low permeability and ultra-low permeability reservoirs. According to the reservoir distribution characteristics and related data, the Chang 6 reservoir in the study area is divided into two types, mainly Class II and Class III reservoirs. The comprehensive evaluation predicts that the spatial distribution of the favorable area of Chang 6 reservoir is not uniform, but the distribution area is large, which has broad exploration and development value, and provides the necessary conditions for the distribution study of the favorable oil-bearing zone in this area and the preparation for the next exploration and development.