This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the i...This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the industrial sector and public sector. The industrial sector provides goods in perfectly competitive markets. The public sector, which is financed by the regional government’s tax incomes, supplies regional public goods. The public goods affect both firms and households. We show how to find equilibrium values of the dynamic system and simulate model. Then, we carry out comparative statics analysis with regard to parameter changes in tax rates, congestion and amenity. Our comparative statics analysis provides some important insights. For instance, a main difference between the effects of increasing the two regions’ tax rates on the output is that as the technologically advanced region’s (the other region’s) tax rate on the industrial sector is increased, the national industrial output, national capital employed by the economy, and the national wealth are increased (reduced). In the region which increases the tax rate, the wage rate, consumption and wealth per capita, output per labor force, the population, and land rent are increased, and the corresponding variables in the other region are reduced.展开更多
Reform and opening up has made China’s economy develop faster than ever. But it has not succeeded in changing the regional disparity in China. In this article, we establish a model factor input called the "lock-...Reform and opening up has made China’s economy develop faster than ever. But it has not succeeded in changing the regional disparity in China. In this article, we establish a model factor input called the "lock-in effect" and analyze the channel of the lock-in effect and how it influences the regional economy. On the analyses of thirty provinces’ panel data in China from 1990 to 2005, we find that the lock-in effect of factor inputs further exacerbates the developmental imbalance among regions.展开更多
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. Accor...Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.展开更多
Xinjiang is a good place, with pastureland to the north and south of the Tianshan MountainThe Gobi Desert has been changed into fertile fields, irrigated by melting snows.
Stability assessment is one of the most important issues in mining ground control. Mine development and/or production instability can cause production delay, loss of reserves, as well as injury to miners. Within the s...Stability assessment is one of the most important issues in mining ground control. Mine development and/or production instability can cause production delay, loss of reserves, as well as injury to miners. Within the scope of this study, a series of open stope’s instability under the influence of overlaying mined-out regions were carried out with different mining scenarios at Modi Taung gold mine which is operated by National Prosperity Gold Production Group Limited (NPGPGL) in Myanmar. NPGPGL has been developing stopes up to 150 m from the surface at Shwesin vein system, and the mining activities are going to continue to deeper levels to fulfill the ore mineral supply. Creating a new stope opening under overlaying mined-out regions is not easy considering the instability of mined-out regions can affect the stope. The instability of new stope opening is not only due to its own induced stress but also the strong influence by the mined-out regions situated on upper part of the stope. Therefore, the understandings of ground behaviors and failure mechanisms of new stope opening due to the influence of overlaying mined-out regions are paramount to be studied. This paper describes in detail the strength factor and failure zones under the overlaying mined-out regions with different mine conditions by using numerical simulations, 3D finite difference software (FLAC 3D).展开更多
Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal ...Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869.展开更多
The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will ...The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will greatly deepen the coupling of the electricity-gas integrated energy system,improve the flexibility and safety of the operation of the power system,and bring a deal of benefits to the power system.On this background,an optimal dispatch model of RIES combined cold,heat,gas and electricity with SOP is proposed.Firstly,RIES architecture with SOP and P2G is designed and its mathematical model also is built.Secondly,on the basis of considering the optimal scheduling of combined cold,heat,gas and electricity,the optimal scheduling model for RIES was established.After that,the original model is transformed into a mixed-integer second-order cone programming model by using linearization and second-order cone relaxation techniques,and the CPLEX solver is invoked to solve the optimization problem.Finally,the modified IEEE 33-bus systemis used to analyze the benefits of SOP,P2G technology and lithium bromide absorption chillers in reducing systemnetwork loss and cost,as well as improving the system’s ability to absorb wind and solar and operating safety.展开更多
It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is adva...It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.展开更多
The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component an...The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.展开更多
The article Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018,written by Jawaria GUL,Sher MUHAMMAD,LIU Shi-yin,Siddique ULLAH,Shakeel AHMAD...The article Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018,written by Jawaria GUL,Sher MUHAMMAD,LIU Shi-yin,Siddique ULLAH,Shakeel AHMAD,Huma HAYAT and Adnan Ahmad TAHIR,was originally published Online First without Open Access.After publication in volume 17,issue 3,page 572-587,the author decided to opt for Open Choice and to make the article an Open Access publication.Therefore,the copyright of the article has been changed to C The Author(s)2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/),which permits use,duplication,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license,and indicate if changes were made.The original version of this article has been revised due to a retrospective Open Access order.展开更多
The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC)is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center(GAC) in the g,r,i bands. Half of its s...The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC)is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center(GAC) in the g,r,i bands. Half of its survey field is located on the Galactic Anti-center disk,which makes XSTPSGAC highly suitable to search for new open clusters in the GAC region. In this paper,we report new open cluster candidates discovered in this survey,as well as properties of these open cluster candidates,such as age,distance and reddening,derived by isochrone fitting in the color-magnitude diagram(CMD).These open cluster candidates are stellar density peaks detected in the star density maps by applying the method from Koposov et al. Each candidate is inspected in terms of its true color image composed from three XSTPS-GAC band images. Then its CMD is checked,in order to identify whether the central region stars have a clear isochrone-like trend differing from background stars. The parameters derived from isochrone fitting for these candidates are mainly based on three band photometry of XSTPS-GAC.Moreover,when these new candidates are able to be seen clearly in 2 MASS data,their parameters are also derived based on the 2 MASS(J-H,J) CMD. There are a total of 320 known open clusters rediscovered and 24 new open cluster candidates discovered in this work. Furthermore,the parameters of these new candidates,as well as another 11 previously known open clusters,are properly determined for the first time.展开更多
Salmonella is one of the major pathogenic bacteria present in contaminated water. 16-23S rRNA spacer region has been reported to be polymorphic at serovar level in Salmonella. Salmonella isolates obtained from Ganges ...Salmonella is one of the major pathogenic bacteria present in contaminated water. 16-23S rRNA spacer region has been reported to be polymorphic at serovar level in Salmonella. Salmonella isolates obtained from Ganges river water were studied for 16-23S rRNA spacer region polymorphism. Thirty three isolates belonging to eight serovars (S. Typhimurium, S. Abuja, S. Pantypridd, S. Lagos, S. Chinkual, S. Zwickau, S. Goldenberg and S. Oritamerin) were studied for the polymorphism. Out of 33 isolates, 15 different profiles were observed no serovar specific profile. Our findings indicate that 16-23S rRNA spacer region is not specific at serovar level, but can be used for differentiation of different Salmonella isolates.展开更多
Since the 18 th National Congress of the Communist Party of China,the central government has implemented several regional development plans,including the Belt and Road Initiative and the Yangtze River Economic Belt,ai...Since the 18 th National Congress of the Communist Party of China,the central government has implemented several regional development plans,including the Belt and Road Initiative and the Yangtze River Economic Belt,aiming to reshape the economic geography of China.This paper is based on the Belt and Road Initiative and the Yangtze River Economic Belt and outlines the pattern of opening up.To analyze the impact of the pattern of opening up on the regional integration of China's economic geography,this paper has developed a new economic geography model comprised of four regions and two countries.From this,it draws some conclusions.First,the change of pattern of opening up will lead to shifting centripetal and centrifugal forces from the international market.The greater the scale of neighboring markets,the stronger the agglomeration force will be; the more product varieties made in neighboring countries,the more potent its dispersion force.Second,developing an inland international trade corridor will decentralize industry distribution and reduce the impact of external market integration on home countries.Third,the inland international trade corridor could alter the effect of domestic market integration on the economic geography.When domestic integration occurs prior to international integration,further integration of a domestic market leads to greater industrial distribution along a bell-shaped curve,which describes economic activities from dispersion to agglomeration to decentralization.Therefore,developing an integrated market system of major countries and opening a corridor between China and Europe is not only the key to reshaping China's economic geography but also the path to solving the problems of the Heihe-Tengchong Line.展开更多
This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (〈 100 pc) from the Gaia-DR1 catalog,...This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (〈 100 pc) from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions (the Hyades and Coma Berenices (Coma Ber) open clusters), and obtain 57 reliable cluster members. Based on these cluster members, the distances to the Hyades and Coma Ber clusters are determined to be 46.0±0.2 and 83.5±0.3 pc, respectively. Our results demonstrate that the KNND method can be used to detect open clusters based on a large volume of astrometry data.展开更多
文摘This paper develops a two-regional growth model with amenity, capital accumulation and regional public goods with public goods and fiscal policies. The economy consists of two regions and each region consists of the industrial sector and public sector. The industrial sector provides goods in perfectly competitive markets. The public sector, which is financed by the regional government’s tax incomes, supplies regional public goods. The public goods affect both firms and households. We show how to find equilibrium values of the dynamic system and simulate model. Then, we carry out comparative statics analysis with regard to parameter changes in tax rates, congestion and amenity. Our comparative statics analysis provides some important insights. For instance, a main difference between the effects of increasing the two regions’ tax rates on the output is that as the technologically advanced region’s (the other region’s) tax rate on the industrial sector is increased, the national industrial output, national capital employed by the economy, and the national wealth are increased (reduced). In the region which increases the tax rate, the wage rate, consumption and wealth per capita, output per labor force, the population, and land rent are increased, and the corresponding variables in the other region are reduced.
文摘Reform and opening up has made China’s economy develop faster than ever. But it has not succeeded in changing the regional disparity in China. In this article, we establish a model factor input called the "lock-in effect" and analyze the channel of the lock-in effect and how it influences the regional economy. On the analyses of thirty provinces’ panel data in China from 1990 to 2005, we find that the lock-in effect of factor inputs further exacerbates the developmental imbalance among regions.
文摘Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are:sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.
文摘Xinjiang is a good place, with pastureland to the north and south of the Tianshan MountainThe Gobi Desert has been changed into fertile fields, irrigated by melting snows.
文摘Stability assessment is one of the most important issues in mining ground control. Mine development and/or production instability can cause production delay, loss of reserves, as well as injury to miners. Within the scope of this study, a series of open stope’s instability under the influence of overlaying mined-out regions were carried out with different mining scenarios at Modi Taung gold mine which is operated by National Prosperity Gold Production Group Limited (NPGPGL) in Myanmar. NPGPGL has been developing stopes up to 150 m from the surface at Shwesin vein system, and the mining activities are going to continue to deeper levels to fulfill the ore mineral supply. Creating a new stope opening under overlaying mined-out regions is not easy considering the instability of mined-out regions can affect the stope. The instability of new stope opening is not only due to its own induced stress but also the strong influence by the mined-out regions situated on upper part of the stope. Therefore, the understandings of ground behaviors and failure mechanisms of new stope opening due to the influence of overlaying mined-out regions are paramount to be studied. This paper describes in detail the strength factor and failure zones under the overlaying mined-out regions with different mine conditions by using numerical simulations, 3D finite difference software (FLAC 3D).
基金the National Natural Science Foundation of China(NSFC)through grants 12003022,12373035,12233009 and 12173047support from the Youth Innovation Promotion Association of the CAS(grant No.2022055)。
文摘Open clusters are the basic building blocks that serve as a laboratory for the study of young stellar populations in the Milky Way.Variable stars in open clusters provide a unique way to accurately probe the internal structure,temporal and dynamical evolutionary stages of individual stars and the host cluster.The most powerful tool for such studies is time-domain photometric observations.This paper follows the route of our previous work,concentrating on a photometric search for variable stars in NGC 884.The target cluster is the companion of NGC869,forming the well-known double cluster system that is gravitationally bound.From the observation run in 2016 November,a total of 9247 B-band CCD images and 8218Ⅴ-band CCD images were obtained.We detected a total of 15 stars with variability in visual brightness,including five Be stars,three eclipsing binaries,and seven of unknown types.Two new variable stars were discovered in this work.We also compared the variable star content of NGC 884 with its companion NGC 869.
基金Project Supported by National Natural Science Foundation of China(51777193).
文摘The Regional Integrated Energy System(RIES)has brought new modes of development,utilization,conversion,storage of energy.The introduction of Soft Open Point(SOP)and the application of Power to Gas(P2G)technology will greatly deepen the coupling of the electricity-gas integrated energy system,improve the flexibility and safety of the operation of the power system,and bring a deal of benefits to the power system.On this background,an optimal dispatch model of RIES combined cold,heat,gas and electricity with SOP is proposed.Firstly,RIES architecture with SOP and P2G is designed and its mathematical model also is built.Secondly,on the basis of considering the optimal scheduling of combined cold,heat,gas and electricity,the optimal scheduling model for RIES was established.After that,the original model is transformed into a mixed-integer second-order cone programming model by using linearization and second-order cone relaxation techniques,and the CPLEX solver is invoked to solve the optimization problem.Finally,the modified IEEE 33-bus systemis used to analyze the benefits of SOP,P2G technology and lithium bromide absorption chillers in reducing systemnetwork loss and cost,as well as improving the system’s ability to absorb wind and solar and operating safety.
文摘It has been found that there are marked errors in the value of valid opening size of heat-bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs are flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening teat and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heatbonded nonwoven fabrics.
文摘The study profiles and explains the significant changes that have taken place in China's spatial development patterns since the inception of its economic reform and opening two decades ago. Principal component analysis is used to delineate spatial patterns. The analyses show that prior to the reform China's spatial development pattern was characterized by the dominance of the three municipalities and the Northeast, as well as by both the coast-interior and the north-south disparities. Northern provinces were generally more industrialized and economically powerful than the southern ones. After two decades of reform, regional development has become multi-centered with South China, the Yangtze Delta and the Beijing-Tianjin area being the three most important regions of the country. The coastal provinces as a whole rose to prominence on China's economic map while the Northeast has diminished its clout. The coast-interior gap not only remains but may have widened. The north-south disparity also still exists but there has been a role reversal with the south now in the lead position. Virtually all inland provinces now find themselves at or near the low end of the development spectrum. We argue that the major reason for the recent shifts in Chinese space economy is the spatially differentiated economic growth resulted from the reform and open door policy and from the new, uneven development strategy adopted by the Chinese government. The paper discusses four specific factors that have reshaped China's spatial development patterns.
文摘The article Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018,written by Jawaria GUL,Sher MUHAMMAD,LIU Shi-yin,Siddique ULLAH,Shakeel AHMAD,Huma HAYAT and Adnan Ahmad TAHIR,was originally published Online First without Open Access.After publication in volume 17,issue 3,page 572-587,the author decided to opt for Open Choice and to make the article an Open Access publication.Therefore,the copyright of the article has been changed to C The Author(s)2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/),which permits use,duplication,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license,and indicate if changes were made.The original version of this article has been revised due to a retrospective Open Access order.
基金supported by the National Natural Science Foundation of China (NSFC,Grant Nos.11473001,11233004,11078006,11633009 and 11273067)the Minor Planet Foundation of Purple Mountain Observatory+2 种基金supported by the National Key Basic Research Program of China (2014CB845700)the China Postdoctoral Science Foundation (Grant No.2017M610695)supported by Special Funding for Advanced Users,budgeted and administrated by the Center for Astronomical Mega-Science,Chinese Academy of Sciences
文摘The Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC)is a photometric sky survey that covers nearly 6000 deg^2 towards the Galactic Anti-center(GAC) in the g,r,i bands. Half of its survey field is located on the Galactic Anti-center disk,which makes XSTPSGAC highly suitable to search for new open clusters in the GAC region. In this paper,we report new open cluster candidates discovered in this survey,as well as properties of these open cluster candidates,such as age,distance and reddening,derived by isochrone fitting in the color-magnitude diagram(CMD).These open cluster candidates are stellar density peaks detected in the star density maps by applying the method from Koposov et al. Each candidate is inspected in terms of its true color image composed from three XSTPS-GAC band images. Then its CMD is checked,in order to identify whether the central region stars have a clear isochrone-like trend differing from background stars. The parameters derived from isochrone fitting for these candidates are mainly based on three band photometry of XSTPS-GAC.Moreover,when these new candidates are able to be seen clearly in 2 MASS data,their parameters are also derived based on the 2 MASS(J-H,J) CMD. There are a total of 320 known open clusters rediscovered and 24 new open cluster candidates discovered in this work. Furthermore,the parameters of these new candidates,as well as another 11 previously known open clusters,are properly determined for the first time.
文摘Salmonella is one of the major pathogenic bacteria present in contaminated water. 16-23S rRNA spacer region has been reported to be polymorphic at serovar level in Salmonella. Salmonella isolates obtained from Ganges river water were studied for 16-23S rRNA spacer region polymorphism. Thirty three isolates belonging to eight serovars (S. Typhimurium, S. Abuja, S. Pantypridd, S. Lagos, S. Chinkual, S. Zwickau, S. Goldenberg and S. Oritamerin) were studied for the polymorphism. Out of 33 isolates, 15 different profiles were observed no serovar specific profile. Our findings indicate that 16-23S rRNA spacer region is not specific at serovar level, but can be used for differentiation of different Salmonella isolates.
基金a staged research result of "Studies on New Strategic Regions Contributing to China’s Economic Growth in the Future"(14ZDA024)a major program of the National Social Science Fund of China+3 种基金"Studies on Regional Integration and Welfare Compensation on the Basis of Dynamic CGE and DCI Models"(71173101)a program funded by the National Natural Science Foundation of China"Studies on Path and Mechanism to Improve Economic Performance and Quality in Jiangsu Province from the Perspective of the Supply Side"(BRA2017358)a Jiangsu "333" High-level Cultivation Program
文摘Since the 18 th National Congress of the Communist Party of China,the central government has implemented several regional development plans,including the Belt and Road Initiative and the Yangtze River Economic Belt,aiming to reshape the economic geography of China.This paper is based on the Belt and Road Initiative and the Yangtze River Economic Belt and outlines the pattern of opening up.To analyze the impact of the pattern of opening up on the regional integration of China's economic geography,this paper has developed a new economic geography model comprised of four regions and two countries.From this,it draws some conclusions.First,the change of pattern of opening up will lead to shifting centripetal and centrifugal forces from the international market.The greater the scale of neighboring markets,the stronger the agglomeration force will be; the more product varieties made in neighboring countries,the more potent its dispersion force.Second,developing an inland international trade corridor will decentralize industry distribution and reduce the impact of external market integration on home countries.Third,the inland international trade corridor could alter the effect of domestic market integration on the economic geography.When domestic integration occurs prior to international integration,further integration of a domestic market leads to greater industrial distribution along a bell-shaped curve,which describes economic activities from dispersion to agglomeration to decentralization.Therefore,developing an integrated market system of major countries and opening a corridor between China and Europe is not only the key to reshaping China's economic geography but also the path to solving the problems of the Heihe-Tengchong Line.
基金supported by the National Natural Science Foundation of China(NSFC,Grant No.11403004)
文摘This paper presents a preliminary test of the k-th nearest neighbor distance (KNND) method for detecting nearby open clusters based on Gaia-DR1. We select 38 386 nearby stars (〈 100 pc) from the Gaia-DR1 catalog, and then use the KNND method to detect overdense regions in three-dimensional space. We find two overdense regions (the Hyades and Coma Berenices (Coma Ber) open clusters), and obtain 57 reliable cluster members. Based on these cluster members, the distances to the Hyades and Coma Ber clusters are determined to be 46.0±0.2 and 83.5±0.3 pc, respectively. Our results demonstrate that the KNND method can be used to detect open clusters based on a large volume of astrometry data.