The Yemaomian landslide,the largest near-dam accumulation landslide in the Three Gorges Reservoir area,is situated 17 km upstream of the Three Gorges Dam.Nearly 20 years of monitoring data indicate that the landslide ...The Yemaomian landslide,the largest near-dam accumulation landslide in the Three Gorges Reservoir area,is situated 17 km upstream of the Three Gorges Dam.Nearly 20 years of monitoring data indicate that the landslide has been undergoing slow deformation with a low deformation rate and magnitude.This paper applies a stepwise linear regression method and a mechanical model of hydrodynamics triggering to deeply explore the relationship between geological conditions,external factors,and deformation characteristics.Based on the stage transition characteristics of external triggering factors,the deformation evolution process of the landslide since the reservoir impoundment is divided into three stages:(1)June 2003-September 2006,the landslide was reactivated by the significant rise in reservoir water levels,in a retrogressive mode;(2)October 2006-September 2018,the deformation mode shifted from retrogressive mode to creep deformation as a whole,primarily due to the degradation effect on the landslide mass caused by immersion in reservoir water.(3)October 2018-February 2024,a further significant reduction in the overall deformation rate and the impact of seasonal rainfall on landslide deformation surpassed that of reservoir water level fluctuations.The main component of landslide deformation is convergent creep,and extreme rainfall will be an important triggering factor for the local instability.Identifying the deformation evolution stages and determining the dominant external influencing factors at each stage is crucial for landslide research,and this paper provides an effective research paradigm for this purpose.展开更多
The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy...The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent yields.To analyze the correlation between SST in different larval stages and the corresponding yield of P.trituberculatus,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low SST.The distribution of particles in the megalopa stage(M stage)were located in the region of the lower temperature.In 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time period.In 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast.The correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of P.trituberculatus decreased significantly(R=-0.772,P=0.015)with increasing SST at the M stage.This study preliminarily explains the correlation between SST at the larval stage and the yield of P.trituberculatus and provides essential information for scientific stock enhancement in the future.展开更多
As important mechanisms of regional strategy and policy, prefecture-level regions have played an increasingly significant role in the development of China＇s economy. However, little research has grasped the essence o...As important mechanisms of regional strategy and policy, prefecture-level regions have played an increasingly significant role in the development of China＇s economy. However, little research has grasped the essence of the economic development stage and the spatio-temporal evolution process at the prefecture level; this may lead to biased policies and their ineffective implementations. Based on Chenery＇s economic development theory, this paper identifies China＇s economic development stages at both national and prefectural levels. Both the Global Moran I index and the Getis-Ord Gi＊ index are employed to investigate the spatio-temporal evolution of China＇s economic development from 1990 to 2010. Major conclusions can be drawn as follows. （1） China＇s economic development is generally in the state of agglomeration. It entered the Primary Production Stage in 1990, and the Middle Industrialized Stage in 2010, with a ＇balanced-unbalanced-gradually rebalanced＇ pattern in the process. （2） China＇s rapid economic growth experienced a spatial shift from the coastal areas to the the inland areas. Most advanced cities in mid-western China can be roughly categorized into regional hub cities and resource-dependent cities. （3） Hot spots in China＇s economy moved northward and westward. The interactions between cities and prefectures became weaker in Eastern China, while cities and prefectures in Central and Western China were still at the stage of individual development, with limited effect on the surrounding cities. （4） While the overall growth rate of China＇s economy has gradually slowed down during the past two decades, the growth rate of cities and prefectures in Central and Western China was much faster than those in coastal areas. （5） Areas rich in resources, such as Xinjiang and Inner Mongolia, have become the new hot spots of economic growth in recent years. For these regions, however, more attention needs to be paid to their unbalanced industrial structures and the lagging social development against the backdrop of the rapid economic growth, driven predominantly by the exploitation of resources.展开更多
Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations i...Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations in conventional remote sensing(RS) approaches limited their applications over broad regions. In this study, a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) was developed to estimate regional maize yield, and it was implemented using eight data-model coupling strategies(DMCSs) over the Northeast China Plain(NECP). Simulations under eight DMCSs were validated against the prefecture-level statistics(2010–2012) reported by National Bureau of Statistics of China, and inter-compared. The 3-year averaged result could give more robust estimate than the yearly simulation for maize yield over space. A 3-year averaged validation showed that prefecture-level estimates by PRYM–Maize under DMCS8, which coupled with the development stage(DVS)-based grain-filling algorithm and RS phenology information and leaf area index(LAI), had higher correlation(R, 0.61) and smaller root mean standard error(RMSE, 1.33 t ha^(–1)) with the statistics than did PRYM–Maize under other DMCSs. The result also demonstrated that DVS-based grain-filling algorithm worked better for maize yield than did the harvest index(HI)-based method, and both RS phenology information and LAI worked for improving regional maize yield estimate. These results demonstrate that the developed PRYM–Maize under DMCS8 gives reasonable estimates for maize yield and provides scientific basis facilitating the understanding the spatial variations of maize yield over the NECP.展开更多
Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landfor...Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.展开更多
The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle m...The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline.展开更多
Nanoparticles are widely observed in the natural shear zone and experimental slip faults, which can lubricate the fault and significantly reduce the friction coefficient during seismic slip. But it is still not clear ...Nanoparticles are widely observed in the natural shear zone and experimental slip faults, which can lubricate the fault and significantly reduce the friction coefficient during seismic slip. But it is still not clear how the nanoparticles develop during the process of sliding. Clarifying the development stage of nanoparticles in a fault zone is critical to understanding the formation mechanisms of nanoparticles and the mechanism of fault weakening from a nanoperspective. In this study, four types of nanoparticles were found in the Indosinian Xiaomei shear zone, including spherical nanoparticles, rod-like nanograins and their aggregations. Ultramicroscopic analyses indicate that polished patches are highly smooth and composed of tightly packed spherical nanoparticles and well orientated rod-like nanograins during slip at high velocities. Meanwhile, the dome nanoparticles were formed by the calcite thermal decomposition due to frictional heat during highspeed sliding. The polygonal grooves are possibly related to high temperature(>900℃) grain boundary sliding deformation mechanisms. However, the porous and rough surfaces are accompanied by a series of holes and parallel "scratches" during a subsequent low-velocity stage. To ascertain the chemical composition of these nanoparticles, the energy dispersive spectrometer(EDS) test were conducted. The results suggest that materials rich in Fe, MgO and wollastonite are likely to form the rod-like nanograins, while materials rich in SiO2 are likely to form the spherical nanoparticles.展开更多
Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural prod...Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural products in the world,and its agricultural production change has international influence. In this paper,starting from two angles of EU agricultural development scale and target,development stage of its agricultural production is explored,and development and evolution causes of EU agriculture are analyzed: efficiency and benefit targets cause change of EU agricultural management model; change of agricultural product supply-demand pattern leads the evolution of EU agricultural development idea; the reflection of agricultural development target impels the transformation of EU agricultural development. On this basis,the below conclusions are obtained: agricultural development could evolve according to the changes of economic and social conditions; it is a necessary requirement of promoting internal market stability and international market harmony to actively use agricultural support policies adapting to agricultural development at each stage; it is an important measurement of impelling agricultural modernization process to promote innovation of agricultural management model and development of market integration; it is an inevitable road of realizing sustainable development of agriculture to develop ecological agriculture and emphasize equal development of agriculture and countryside. On this basis,it could provide the reference for agricultural development of China based on EU agricultural development experience.展开更多
This paper constructs the index system of the regional division of the development stage of China's wind power resources,including the index of energy,the index of wind energy endowments and other indices.Based on...This paper constructs the index system of the regional division of the development stage of China's wind power resources,including the index of energy,the index of wind energy endowments and other indices.Based on principal component analysis and layered clustering analysis of these indices,and combined with the conceptual function of the development and utilization stage of the wind power,this paper divides the development and utilization stage of the wind power into four stages taking province as the basic yardstick:optimization growth stage,the rapid growth stage,the slow growth stage and the initial growth stage.In addition,this paper briefly discusses the basic strategy that should be adopted in each development stage of wind power resources.展开更多
China has basically succeeded in its quantitative catch-up with advanced economies and has now entered into a new stage of economic development focused on the greater efficiency of resource allocation. In order to ach...China has basically succeeded in its quantitative catch-up with advanced economies and has now entered into a new stage of economic development focused on the greater efficiency of resource allocation. In order to achieve the objectives of the 13th Five-Year Plan for National Economic and Social Development, efforts must be made to reform the ＂petty-farmer＂ economic mode of production while promoting specialization, modernization, and economies of scale. The restructuring and upgrade of the manufacturing sector should be focused on existing industries and the development of high-end industries while maintaining China＇s comparative advantage in narrowing technology gaps with advanced economies. The goal should be to transform China from a large industrial manufacturer into a competitive one. Technological innovation should be based on demand, supported by projects, carried out by firms through the social division of labor, and work to increase the capacity of la^e enterprises to integrate the results of innovation. Materialized labor consumption and logistical costs must be reduced, and the quality and level of urbanization must be increased. To assist productivity development, urban citizenship should be granted to rural migrant workers. In addition, the urbanization of those who remain in the countryside should be promoted in order for rural populations to enjoy the benefits of industrially robust, technologically modern and ecologically sound civilization.展开更多
The economic and technological development zones (ETDZ) in China began their 11th year in 1995. Since 1984 the State Council has approved 32 ETDZs. In the past few years the ETDZs have gained remarkable achievements i...The economic and technological development zones (ETDZ) in China began their 11th year in 1995. Since 1984 the State Council has approved 32 ETDZs. In the past few years the ETDZs have gained remarkable achievements in improving the investment climate, raising the management and service level and attracting foreign funds. The economic benefits have had a simultaneous develonment in the first 14 ETDZs in展开更多
1. Review of railway work in 1996 The year 1996 was an important year for China’s railways in facing a historic turning point—— committing itself to a programme of structural re-
I Since 1990, as a person in charge of key research projects of the China Tibetology Research Center, I have had opportunities almost every year to conduct field surveys on anthropology in Tibet together with my colle...I Since 1990, as a person in charge of key research projects of the China Tibetology Research Center, I have had opportunities almost every year to conduct field surveys on anthropology in Tibet together with my colleagues. Our investigations focus on the family. The purpose of our surveys is to see social changes in Tibet during the 50 years after the Democratic Reform through the study of the family as a social cell.展开更多
Under the situation of modern social and economic development, China's industrial and commercial management occupies an important position. The reason is that some enterprises of different sizes gradually fade out...Under the situation of modern social and economic development, China's industrial and commercial management occupies an important position. The reason is that some enterprises of different sizes gradually fade out of the market because they do not conform to the industrial and commercial management regulations. The most urgent task is to govern these enterprises that do not conform to the industrial and commercial management regulations. This also puts forward more stringent requirements for the majority of enterprises. They should pay constant attention to their own industrial and commercial management issues to ensure that all enterprises' operations comply with market regulations and relevant laws and regulations, and to provide practical safeguard measures for the normal operation of the market economy.展开更多
As a major developing country,China has attracted significant attention as to whichpathitshouldfol owfortechnologicalprogress.Accordingtotheauthorofthispaper,Chinashouldcontinueto pursue the international division of ...As a major developing country,China has attracted significant attention as to whichpathitshouldfol owfortechnologicalprogress.Accordingtotheauthorofthispaper,Chinashouldcontinueto pursue the international division of labor and competition strategy based on comparative advantages.Meanwhile,China should,through reform and adjustment,build a national innovation system capable ofplaying an e ective role in the future.However,laying too much emphasis on proprietary innovation atthe present stage wil bring about undesirable consequences.The timing for China to embark on a path oftechnologicaldevelopmentthroughproprietaryinnovationissubjecttothechangesbothintradeconditionsandin income distribution e ects arising from proprietary innovation.展开更多
On January 21,the 13th Annual China Textile Roundtable,"Shuyang Cup"·The 6th China Textile News Award Ceremony,and the First Award Ceremony of the Qualified Enterprises for the Review of the Quality Awa...On January 21,the 13th Annual China Textile Roundtable,"Shuyang Cup"·The 6th China Textile News Award Ceremony,and the First Award Ceremony of the Qualified Enterprises for the Review of the Quality Awards of the National Textile Industry were held in Beijing.展开更多
In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the...In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the single well is very low, which results in the deterioration of the effect in the development process of many oilfields and the loss in oilfield development. Therefore, in order to improve the benefit of oilfield development and the effect of water flooding development, this paper makes an in-depth study on the water-stable and oil-efficient development of high-water-cut and later-stage complex fault-block oilfields.展开更多
Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped ste...Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped stemborer Chilo suppressalis in rice fields during 18—27 days after transplantating. The impacts of timing and insecticides on the population development of brown planthopper Nilaparavata lugens was surveyed by direct counting on the plants or by tapping method.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U2340226,12072047,42277186)China Three Gorges Corporation under the contract of No.0799291(SXSN/5115)the Fundamental Research Funds for Central Public Welfare Research Institutes(CKSF20241014/YT,CKSF20241016/YT).
文摘The Yemaomian landslide,the largest near-dam accumulation landslide in the Three Gorges Reservoir area,is situated 17 km upstream of the Three Gorges Dam.Nearly 20 years of monitoring data indicate that the landslide has been undergoing slow deformation with a low deformation rate and magnitude.This paper applies a stepwise linear regression method and a mechanical model of hydrodynamics triggering to deeply explore the relationship between geological conditions,external factors,and deformation characteristics.Based on the stage transition characteristics of external triggering factors,the deformation evolution process of the landslide since the reservoir impoundment is divided into three stages:(1)June 2003-September 2006,the landslide was reactivated by the significant rise in reservoir water levels,in a retrogressive mode;(2)October 2006-September 2018,the deformation mode shifted from retrogressive mode to creep deformation as a whole,primarily due to the degradation effect on the landslide mass caused by immersion in reservoir water.(3)October 2018-February 2024,a further significant reduction in the overall deformation rate and the impact of seasonal rainfall on landslide deformation surpassed that of reservoir water level fluctuations.The main component of landslide deformation is convergent creep,and extreme rainfall will be an important triggering factor for the local instability.Identifying the deformation evolution stages and determining the dominant external influencing factors at each stage is crucial for landslide research,and this paper provides an effective research paradigm for this purpose.
基金Supported by the National Key Research and Development Program of China(No.2019YFD0901304)the Public Welfare Technology Application Research Project of Zhejiang(No.LGN21C190009)the Science and Technology Project of Zhoushan(No.2022C41003)。
文摘The early life stages of marine organisms are pivotal in shaping community dynamics and resource availability.In this study,we focused on Portunus trituberculatus,a crustacean integral to China's fisheries economy,and examined the effect of sea surface temperature(SST)in its critical early life stages on subsequent yields.To analyze the correlation between SST in different larval stages and the corresponding yield of P.trituberculatus,we simulated the transport and distribution of larvae from 2014 to 2022 by employing circulation models and Lagrangian particle tracking experiments(LPTE).In the five years(2014,2015,2016,2019,and 2020),particles were transported in a northwestern direction and moved in the direction of low SST.The distribution of particles in the megalopa stage(M stage)were located in the region of the lower temperature.In 2017,2018,and 2021,the particles were transported in a northeastern direction but they did not move with the gradient of low SST in these years,and the particles in the last M stage were located in the region where the SST was at the peak of the time period.In 2022,the distribution was observed for most of the particles in the southwestern part of Zhejiang coast,a small part of them were transported in the northwestern direction and a small amount of particles was distributed offshore along the northern area of the Zhejiang coast.The correlations between the SST at each stage of larvae with the corresponding year's yield showed that the yield of P.trituberculatus decreased significantly(R=-0.772,P=0.015)with increasing SST at the M stage.This study preliminarily explains the correlation between SST at the larval stage and the yield of P.trituberculatus and provides essential information for scientific stock enhancement in the future.
基金National Natural Science Foundation of China, No.41171107
文摘As important mechanisms of regional strategy and policy, prefecture-level regions have played an increasingly significant role in the development of China＇s economy. However, little research has grasped the essence of the economic development stage and the spatio-temporal evolution process at the prefecture level; this may lead to biased policies and their ineffective implementations. Based on Chenery＇s economic development theory, this paper identifies China＇s economic development stages at both national and prefectural levels. Both the Global Moran I index and the Getis-Ord Gi＊ index are employed to investigate the spatio-temporal evolution of China＇s economic development from 1990 to 2010. Major conclusions can be drawn as follows. （1） China＇s economic development is generally in the state of agglomeration. It entered the Primary Production Stage in 1990, and the Middle Industrialized Stage in 2010, with a ＇balanced-unbalanced-gradually rebalanced＇ pattern in the process. （2） China＇s rapid economic growth experienced a spatial shift from the coastal areas to the the inland areas. Most advanced cities in mid-western China can be roughly categorized into regional hub cities and resource-dependent cities. （3） Hot spots in China＇s economy moved northward and westward. The interactions between cities and prefectures became weaker in Eastern China, while cities and prefectures in Central and Western China were still at the stage of individual development, with limited effect on the surrounding cities. （4） While the overall growth rate of China＇s economy has gradually slowed down during the past two decades, the growth rate of cities and prefectures in Central and Western China was much faster than those in coastal areas. （5） Areas rich in resources, such as Xinjiang and Inner Mongolia, have become the new hot spots of economic growth in recent years. For these regions, however, more attention needs to be paid to their unbalanced industrial structures and the lagging social development against the backdrop of the rapid economic growth, driven predominantly by the exploitation of resources.
基金supported by the National Key Research and Development Program of China(2016YFD0300101,and 2016YFD0300110)the National Natural Science Foundation of China(41871253 and 31671585)+1 种基金the“Taishan Scholar”Project of Shandong Province,Chinathe Key Basic Research Project of Shandong Natural Science Foundation,China(ZR2017ZB0422)。
文摘Spatial dynamics of crop yield provide useful information for improving the production. High sensitivity of crop growth models to uncertainties in input factors and parameters and relatively coarse parameterizations in conventional remote sensing(RS) approaches limited their applications over broad regions. In this study, a process-based and remote sensing driven crop yield model for maize(PRYM–Maize) was developed to estimate regional maize yield, and it was implemented using eight data-model coupling strategies(DMCSs) over the Northeast China Plain(NECP). Simulations under eight DMCSs were validated against the prefecture-level statistics(2010–2012) reported by National Bureau of Statistics of China, and inter-compared. The 3-year averaged result could give more robust estimate than the yearly simulation for maize yield over space. A 3-year averaged validation showed that prefecture-level estimates by PRYM–Maize under DMCS8, which coupled with the development stage(DVS)-based grain-filling algorithm and RS phenology information and leaf area index(LAI), had higher correlation(R, 0.61) and smaller root mean standard error(RMSE, 1.33 t ha^(–1)) with the statistics than did PRYM–Maize under other DMCSs. The result also demonstrated that DVS-based grain-filling algorithm worked better for maize yield than did the harvest index(HI)-based method, and both RS phenology information and LAI worked for improving regional maize yield estimate. These results demonstrate that the developed PRYM–Maize under DMCS8 gives reasonable estimates for maize yield and provides scientific basis facilitating the understanding the spatial variations of maize yield over the NECP.
文摘Threshold is a limit and marginal point when a qualitative change takes place. Since threshold principle was firstly used in landform research by S.A.Schumm in the 1970s, the quantitative research on watershed landform development stage has come true. Davis proposed a three-stage model on landform evolution: young, mature and old stages. Thereafter Strahler quantified this model by hypsometric analysis method. The authors thought that the material movement stage cannot be expressed by hypsometric method in watershed landform at development stage, because of the uncertainty on stage delimitation. To meet this shortcoming, this paper presents an integral erosion value method. A clear delimitation on landform development stage in the Loess Plateau region has been tested by this method. The result shows that gullied loessial hilly area is at the mature stage, and gullied loessial tableland area is at the young stage. It is estimated that from the point of erosion related sediment yield, natural erosion accounts for 70% of the total erosion amount, and artificial accelerating erosion is 30%. Therefore soil and water conservation is very crucial for the Loess Plateau.
基金Supported by the National Natural Science Foundation of China (72088101)。
文摘The continuous growth of recoverable reserves in a waterflooding oilfield has a significant impact on the patterns of production evolution. A new production evolution model is established by improving the Weng Cycle model. With the new model, the statistical correspondence between the production decline stage and the reserve-production imbalance is clarified,and the correlation of water cut with the recovery percent of recoverable reserves is discussed, providing quantitative basis of reservoir engineering for dividing development stages of oilfield and defining mature oilfields. According to the statistics of oilfields in eastern China, the time point corresponding to the reserve-production balance coefficient dropping to less than 1dramatically is well correlated the beginning point of production decline, thus the time when the reserve-production balance coefficient drops dramatically can be taken as the initiation point of production decline stage. The research results show that the water cut and the recovery percent of recoverable reserves have a good statistical match in the high water cut stage, and it is more rational to take both the start point of production decline stage and the water cut of 90%(or the recovery percent of recoverable reserves of 80%) as the critical criteria for defining a mature oilfield. Five production evolution patterns can be summarized as follows: growth–peak plateau–stepped decline, growth–stepped stabilizing–stepped decline, growth–stepped stabilizing–rapid decline, growth–peak plateau–rapid decline, and growth–continuous decline.
基金the National Natural Science Foundation of China(Nos.41776072,41676048,U1701641,91328205)。
文摘Nanoparticles are widely observed in the natural shear zone and experimental slip faults, which can lubricate the fault and significantly reduce the friction coefficient during seismic slip. But it is still not clear how the nanoparticles develop during the process of sliding. Clarifying the development stage of nanoparticles in a fault zone is critical to understanding the formation mechanisms of nanoparticles and the mechanism of fault weakening from a nanoperspective. In this study, four types of nanoparticles were found in the Indosinian Xiaomei shear zone, including spherical nanoparticles, rod-like nanograins and their aggregations. Ultramicroscopic analyses indicate that polished patches are highly smooth and composed of tightly packed spherical nanoparticles and well orientated rod-like nanograins during slip at high velocities. Meanwhile, the dome nanoparticles were formed by the calcite thermal decomposition due to frictional heat during highspeed sliding. The polygonal grooves are possibly related to high temperature(>900℃) grain boundary sliding deformation mechanisms. However, the porous and rough surfaces are accompanied by a series of holes and parallel "scratches" during a subsequent low-velocity stage. To ascertain the chemical composition of these nanoparticles, the energy dispersive spectrometer(EDS) test were conducted. The results suggest that materials rich in Fe, MgO and wollastonite are likely to form the rod-like nanograins, while materials rich in SiO2 are likely to form the spherical nanoparticles.
文摘Agriculture is a basic industry related to national economy and people’s livelihood,and is also the cornerstone of national economic development. European Union(EU) is the second largest exporter of agricultural products in the world,and its agricultural production change has international influence. In this paper,starting from two angles of EU agricultural development scale and target,development stage of its agricultural production is explored,and development and evolution causes of EU agriculture are analyzed: efficiency and benefit targets cause change of EU agricultural management model; change of agricultural product supply-demand pattern leads the evolution of EU agricultural development idea; the reflection of agricultural development target impels the transformation of EU agricultural development. On this basis,the below conclusions are obtained: agricultural development could evolve according to the changes of economic and social conditions; it is a necessary requirement of promoting internal market stability and international market harmony to actively use agricultural support policies adapting to agricultural development at each stage; it is an important measurement of impelling agricultural modernization process to promote innovation of agricultural management model and development of market integration; it is an inevitable road of realizing sustainable development of agriculture to develop ecological agriculture and emphasize equal development of agriculture and countryside. On this basis,it could provide the reference for agricultural development of China based on EU agricultural development experience.
基金National Basic Research and Development Program(973)(Grant no.2007CB210306)
文摘This paper constructs the index system of the regional division of the development stage of China's wind power resources,including the index of energy,the index of wind energy endowments and other indices.Based on principal component analysis and layered clustering analysis of these indices,and combined with the conceptual function of the development and utilization stage of the wind power,this paper divides the development and utilization stage of the wind power into four stages taking province as the basic yardstick:optimization growth stage,the rapid growth stage,the slow growth stage and the initial growth stage.In addition,this paper briefly discusses the basic strategy that should be adopted in each development stage of wind power resources.
文摘China has basically succeeded in its quantitative catch-up with advanced economies and has now entered into a new stage of economic development focused on the greater efficiency of resource allocation. In order to achieve the objectives of the 13th Five-Year Plan for National Economic and Social Development, efforts must be made to reform the ＂petty-farmer＂ economic mode of production while promoting specialization, modernization, and economies of scale. The restructuring and upgrade of the manufacturing sector should be focused on existing industries and the development of high-end industries while maintaining China＇s comparative advantage in narrowing technology gaps with advanced economies. The goal should be to transform China from a large industrial manufacturer into a competitive one. Technological innovation should be based on demand, supported by projects, carried out by firms through the social division of labor, and work to increase the capacity of la^e enterprises to integrate the results of innovation. Materialized labor consumption and logistical costs must be reduced, and the quality and level of urbanization must be increased. To assist productivity development, urban citizenship should be granted to rural migrant workers. In addition, the urbanization of those who remain in the countryside should be promoted in order for rural populations to enjoy the benefits of industrially robust, technologically modern and ecologically sound civilization.
文摘The economic and technological development zones (ETDZ) in China began their 11th year in 1995. Since 1984 the State Council has approved 32 ETDZs. In the past few years the ETDZs have gained remarkable achievements in improving the investment climate, raising the management and service level and attracting foreign funds. The economic benefits have had a simultaneous develonment in the first 14 ETDZs in
文摘1. Review of railway work in 1996 The year 1996 was an important year for China’s railways in facing a historic turning point—— committing itself to a programme of structural re-
文摘I Since 1990, as a person in charge of key research projects of the China Tibetology Research Center, I have had opportunities almost every year to conduct field surveys on anthropology in Tibet together with my colleagues. Our investigations focus on the family. The purpose of our surveys is to see social changes in Tibet during the 50 years after the Democratic Reform through the study of the family as a social cell.
文摘Under the situation of modern social and economic development, China's industrial and commercial management occupies an important position. The reason is that some enterprises of different sizes gradually fade out of the market because they do not conform to the industrial and commercial management regulations. The most urgent task is to govern these enterprises that do not conform to the industrial and commercial management regulations. This also puts forward more stringent requirements for the majority of enterprises. They should pay constant attention to their own industrial and commercial management issues to ensure that all enterprises' operations comply with market regulations and relevant laws and regulations, and to provide practical safeguard measures for the normal operation of the market economy.
文摘As a major developing country,China has attracted significant attention as to whichpathitshouldfol owfortechnologicalprogress.Accordingtotheauthorofthispaper,Chinashouldcontinueto pursue the international division of labor and competition strategy based on comparative advantages.Meanwhile,China should,through reform and adjustment,build a national innovation system capable ofplaying an e ective role in the future.However,laying too much emphasis on proprietary innovation atthe present stage wil bring about undesirable consequences.The timing for China to embark on a path oftechnologicaldevelopmentthroughproprietaryinnovationissubjecttothechangesbothintradeconditionsandin income distribution e ects arising from proprietary innovation.
文摘On January 21,the 13th Annual China Textile Roundtable,"Shuyang Cup"·The 6th China Textile News Award Ceremony,and the First Award Ceremony of the Qualified Enterprises for the Review of the Quality Awards of the National Textile Industry were held in Beijing.
文摘In the process of oilfield development, oilfield dewatering project has always been a big problem for oilfield developers. Because the original oilfield development technology uses a single well, the efficiency of the single well is very low, which results in the deterioration of the effect in the development process of many oilfields and the loss in oilfield development. Therefore, in order to improve the benefit of oilfield development and the effect of water flooding development, this paper makes an in-depth study on the water-stable and oil-efficient development of high-water-cut and later-stage complex fault-block oilfields.
文摘Field experiments were carried out in northern Zhejiang Province. Three insecticides (methamidophos,Shachongshuang and triazophos) were used to control the rice leaffolder Cnaphalocrocis medinalis and rice striped stemborer Chilo suppressalis in rice fields during 18—27 days after transplantating. The impacts of timing and insecticides on the population development of brown planthopper Nilaparavata lugens was surveyed by direct counting on the plants or by tapping method.
