System theory,pressure-state-response and drivingpressure-state-impact-response model have been applied to establishing China's dynamic tracking evaluation system of natural resources security in this article.Base...System theory,pressure-state-response and drivingpressure-state-impact-response model have been applied to establishing China's dynamic tracking evaluation system of natural resources security in this article.Based on analytic hierarchy process and Delphi methods,the natural resources security situation has been evaluated systematically from 1991 to 2007.The result showed that the overall level of China's natural resources security presented a downtrend from 1991 to 2007.The basic reasons are the pressure indicators such as population,GDP,natural resources trade increased gradually,resulting in tension and fragility of natural resources security.展开更多
Japan's economic security strategy has a long history.However,Japan has significantly accelerated its economic security strategy in recent years,especially since the Kishida government came into power.At present,J...Japan's economic security strategy has a long history.However,Japan has significantly accelerated its economic security strategy in recent years,especially since the Kishida government came into power.At present,Japan is gradually forming a comprehensive economic security strategy that has clear strategic objectives,sound institutional settings,enhanced economic control,and closer external cooperation.The Japanese government is accelerating its economic and security strategy because of the changing international environment and Japan's own strategic considerations.Japan hopes to achievemany strategic goals such as improved economy and security through its economic and security strategy,but its strategic effect needs to be verified due to the constraints of many factors.展开更多
Financial Power and Its Strategic Significance A financial crisis hit Asia in 1997. It was both a predatory monetary war a-gainst developing nations launched by the hedge funds and a scramble for fi-nancial supremacy ...Financial Power and Its Strategic Significance A financial crisis hit Asia in 1997. It was both a predatory monetary war a-gainst developing nations launched by the hedge funds and a scramble for fi-nancial supremacy among the monopoly capital in America, Western Eu-rope and Japan. Indeed, the term "Asian financial crisis" is a misnomer. It can nolonger faithfully reflect the scope and essence of the financial storm. Over the pasttwo years, financial turmoil has visited upon Russia and Brazil and has shaken theentire capitalist economic system. In this crash, while Asian nations have展开更多
With the development of economy and the progress of society,people’s living standards are gradually improving,and the requirements for housing are also gradually improving.The development of the real estate industry ...With the development of economy and the progress of society,people’s living standards are gradually improving,and the requirements for housing are also gradually improving.The development of the real estate industry provides conditions for people’s modern life,and its development meets the needs of China’s socialist development.In such a social background,the future planning of the real estate industry is gradually clear,promoting the steady rise of the real estate economy,which is an important development prospect of the current real estate industry.In this paper,through the analysis of real estate economic security and government control,aiming at the existing problems,put forward some effective measures to promote the advantages of real estate development and the combination of government macro-control to stabilize the healthy development of the real estate industry.展开更多
Many heated debates have taken place recently upon the economic security brought about by foreign acquisitions.This should be a good sign,as different views are being aired in contrast to the one uniform voice and has...Many heated debates have taken place recently upon the economic security brought about by foreign acquisitions.This should be a good sign,as different views are being aired in contrast to the one uniform voice and hasty generalization has been replaced by ever-intensifying debate,which is indeed historical progress.展开更多
The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summar...The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summarized, and their relationship was differentiated and analyzed. Based on these, the elements of the conception of agricultural water resources security were hashed and the conception was defined. Agricultural water resources security is the provision of water resource that ensures protection of agriculture against threat, hazards, destruction, and loss. Moreover, the connotation and extension of agricultural water resources security were ascertained. In detail, the connotation of the definition has natural attributes, socioeconomic attributes, and cultural attributes. The extensions of agricultural water resources security include both broad and narrow ones, as well as, food security, agroenvironmental security, agroeconomic security, rural society security, etc. The definition will serve as the frame of reference for developing the researches, limiting the frame of the theory, and founding a appraising system for agricultural water resources security.展开更多
Based on the current cloud computing resources security distribution model’s problem that the optimization effect is not high and the convergence is not good, this paper puts forward a cloud computing resources secur...Based on the current cloud computing resources security distribution model’s problem that the optimization effect is not high and the convergence is not good, this paper puts forward a cloud computing resources security distribution model based on improved artificial firefly algorithm. First of all, according to characteristics of the artificial fireflies swarm algorithm and the complex method, it incorporates the ideas of complex method into the artificial firefly algorithm, uses the complex method to guide the search of artificial fireflies in population, and then introduces local search operator in the firefly mobile mechanism, in order to improve the searching efficiency and convergence precision of algorithm. Simulation results show that, the cloud computing resources security distribution model based on improved artificial firefly algorithm proposed in this paper has good convergence effect and optimum efficiency.展开更多
International trade serves as a crucial pathway for enhancing global food security and equality amid severe food crises worldwide.Under globalization,economic development has profoundly influenced food trade,while dis...International trade serves as a crucial pathway for enhancing global food security and equality amid severe food crises worldwide.Under globalization,economic development has profoundly influenced food trade,while disparities in food purchasing power among different economic development groups have led to uneven food security outcomes.However,the varying contributions of international trade to food security across these groups remain to be quantitatively elucidated.This study categorized countries into four economic development groups—high,high-medium,medium-low,and low—and examined changes in their food security scores from 2010 to 2019.The cross-group contributions of international trade to food security across these groups were compared.The results revealed that the food security score of the high economic development group was 9.22 times higher than that of the low economic development group.From 2010 to 2019,the high economic development group exhibited a significant upward trend in food security scores,whereas the low economic development group showed a significant decline.Moreover,international trade contributed significantly to both cross-group and within-group food security in the high economic development group,while its contribution to the low economic development group remained negligible.These findings demonstrated that international trade has further widened the food security gap between the high and low economic development groups,and its limited contribution to the low economic development group has failed to reverse the declining trend in their food security scores.This study quantified the divergent impacts of international trade on food security across economic development groups,providing valuable insights for optimizing global food trade policies—particularly in addressing the food security challenges faced by low econominc development group.展开更多
Sea lines of communication(SLOCs)security has long been a strategic concern for major powers.Following the establishment of the People’s Republic of China,the country’s focus was on the traditional security aspects ...Sea lines of communication(SLOCs)security has long been a strategic concern for major powers.Following the establishment of the People’s Republic of China,the country’s focus was on the traditional security aspects of its SLOCs.Since the reform and opening-up era-and especially after the end of the Cold War-China has shifted its emphasis toward economic security.China’s SLOCs security bears on multiple dimensions of a holistic approach to national security,encompassing economic security,the safety of its citizens.展开更多
Social security is a product left by economic development. It also has good social security and can effectively promote the development of social security economy. In western countries, social security is when the eco...Social security is a product left by economic development. It also has good social security and can effectively promote the development of social security economy. In western countries, social security is when the economy develops to a certain stage. In order to better meet the needs of human resources development, to provide the masses with a living guarantee, to effectively motivate the masses to work actively, and to achieve stable economic development.展开更多
Super rice is an essendal part of China＇s rice production. Through survey on actual situation of 1568 households of rice growers in Heilongjiang, Hunan and Zhejiang provinces, this paper focused on influence of super...Super rice is an essendal part of China＇s rice production. Through survey on actual situation of 1568 households of rice growers in Heilongjiang, Hunan and Zhejiang provinces, this paper focused on influence of super rice development on increase of China＇s grain yield, influence on increase of rice growers＇ economic in- come, difference in production cost and profit between the North and the South, as well as profit percentage of super rice in production, processing, and sales. It obtained following results： rice price determines rice growers＇ income; expansion of super rice extension area plays a great role in increase of China＇s grain yield; by 2015 and 2020, keeping the yield of other crops not changed, merely the extension of super rice can increase grain for 5 million tons and 11 million tons separately; super rice significantly increases rice growers＇ economic income; for production cost of super rice, the South is higher than the North, and the profit ratio of cost is up to 35.54% on average; with respect of profit in production, processing, and sales, the ratio is 1：2：1.5; with the yield of other crops unchanged, every increase of 1% in area percentage of super rice to rice will additionally produce 1 million tons of grain for China, which is equivalent to saving the yield of 133 300 hm2 farmland and can additional feed 3.5 million people. In view of importance of super rice production, at the same time of strengthening research on super rice variety, it is required to accelerate expanding production area of super rice in suitable areas. Since the development of super rice can support China＇s ration demand of increasing population, China should make effort to realize ＂one yuan for one mu＂ financial subsidy for super rice of main grain production provinces and counties. Besides, China should establish special financial plan for extension of super rice.展开更多
Original ecotourism resources mainly refer to natural and human original ecotourism resources, and it＇s of fragility, rarity and irreversibility. As a valuable historic heritage and hnportant tourism resources, it pl...Original ecotourism resources mainly refer to natural and human original ecotourism resources, and it＇s of fragility, rarity and irreversibility. As a valuable historic heritage and hnportant tourism resources, it plays a significant role in developing tourism and economy in such areas as the underdeveloped areas, the mountain areas and mimority areas. The tourism resources in the western mountain areas of Guangxi owe ,superiorities and characteristics ＇o their original ecology, Yet, western Guangxi is an ethnic region with fragile karst eco-environment, so it is specialto exploit the tourism resources. The paper defines original eeotourism and analyses the specialties and advantages of the original ecotourism resources as well as thefrailty of the ecotourism resources of the region. The ways of thinking are put forward for safe preservation and sustainable development of the original ecotourism resources, i.e. carrying out measures for the multi-grade protection of heritage resources, setting up a ethnic eco-museum/ ethnic culture eco-park and a gene pool of ethnic cultures, etc.展开更多
Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance o...Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.展开更多
The accelerating global energy transition,driven by climate imperatives and technological advancements,demands fundamen-tal transformations in power systems.Smart grids,characterized by cyber-physical integration,dist...The accelerating global energy transition,driven by climate imperatives and technological advancements,demands fundamen-tal transformations in power systems.Smart grids,characterized by cyber-physical integration,distributed renewable resources,and data-driven intelligence,have emerged as the backbone of this evolution.This convergence,however,introduces unprecedented complexities in resilience,security,stability,and market operation.This special issue presents five pivotal studies addressing these interconnected challenges,offering novel methodologies and insights to advance the efficiency,resilience,and sustainability of modern power systems.展开更多
After the analysis of food security of Shandong Province since 1990s, based on the change of grain output and per unit grain yield, it was considered that food production of Shandong Province was generally stable; thr...After the analysis of food security of Shandong Province since 1990s, based on the change of grain output and per unit grain yield, it was considered that food production of Shandong Province was generally stable; through comparing the proportion of per capita possession of grains and per unit grain yield of Shandong Province in the whole country, it revealed that they were higher than the national average level. On this basis, the relationship between land-water resources and food security had been analyzed, and it summarized that Shandong water resources were insufficient, agricultural water was not enough and water had been seriously polluted; and that cultivated area was large and the overall quality was high. Meanwhile, it had analyzed the spatial pattern of land-water resources and the loss of water and soil. Finally, suggestions for the sustainable use of land-water resources in Shandong Province based on food security had been proposed. It should enhance the construction of basic agricultural facilities and implement united dispatching of multiple water resources; strengthen the supervision of cultivated land resources and comprehensively develop reserve resources of cultivated lands; and intensify the treatment of land-water resources and prevention of the loss of water and soil in key areas.展开更多
The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD h...The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.展开更多
Clarifying the relationship between social security and economic development is helpful to realize the sustainable social security system and the stable function of sustainable economic development.In this paper,the e...Clarifying the relationship between social security and economic development is helpful to realize the sustainable social security system and the stable function of sustainable economic development.In this paper,the entropy method,coupling coordination degree,standard deviation ellipse model,and spatial autocorrelation were used to study the spatial-temporal characteristics of coupling coordination of social security and economic development in China from 2002 to 2018.The results indicate that the relationship between social security and economic development in China has been gradually strengthened in the process of mutual adaptation and common development.The benign interaction between the two was unstable,though the coupling coordination degree gradually transitioned to the primary coupling coordination type.Besides,from a spatial perspective,first,the coupling coordination degree of social security and economic development in China contracted in the east-west and north-south directions,and the coupling coordination clustered in the central region in this period;second,the coupling coordination degree generally presented a positive spatial autocorrelation,and regions with similar coupling coordination degrees were in a state of agglomeration;finally,the hot spots clumped together to form a continuous area in the eastern coastal area while the cold spots expanded toward the northwest and northeast.Furthermore,the random distribution areas exhibited a trend of contraction.展开更多
Developing low-carbon and efficient power systems is critical for energy security in the global warming context.We address this issue by focusing on the productivity impact of a decarbonization policy in China’s ther...Developing low-carbon and efficient power systems is critical for energy security in the global warming context.We address this issue by focusing on the productivity impact of a decarbonization policy in China’s thermal power sector—namely,the“Constructing Large Units and Restricting Small Ones”(CLRS)initiative.Utilizing a resource misallocation model,we construct a new theoretical framework to distinguish between technical and allocative efficiency and analyze productivity using plant-level data.The results indicate that the CLRS policy has significantly improved the allocative and technical efficiency of China’s coal-fired power sector,thereby ensuring power security.The closure of outdated and highly distorted small coal-fired units,which have been replaced by technologically advanced large units,primarily drives the enhanced efficiency.The policy’s effects are most pronounced in large-scale power plants and those with high coal combustion efficiency.Furthermore,a comparison of power plants’productivity distribution before and after policy implementation reveals that the CLRS policy not only enhances capital productivity in the coal-fired power sector but also increases rational labor allocation.Our findings have important policy implications for developing countries vis-à-vis building efficient and stable power systems amid climate change.展开更多
基金supported by the National Natural Science Foundation of China(Grant nos.70873119 and 40871253)Chinese Academy of Sciences Knowledge Innovation Program(Grant no.066U0401SZ)
文摘System theory,pressure-state-response and drivingpressure-state-impact-response model have been applied to establishing China's dynamic tracking evaluation system of natural resources security in this article.Based on analytic hierarchy process and Delphi methods,the natural resources security situation has been evaluated systematically from 1991 to 2007.The result showed that the overall level of China's natural resources security presented a downtrend from 1991 to 2007.The basic reasons are the pressure indicators such as population,GDP,natural resources trade increased gradually,resulting in tension and fragility of natural resources security.
基金a phased achievement of the “Important Countries and Regions” Major Research Project of the National Social Science Foundation of China (Grant No. 20VGQ004)
文摘Japan's economic security strategy has a long history.However,Japan has significantly accelerated its economic security strategy in recent years,especially since the Kishida government came into power.At present,Japan is gradually forming a comprehensive economic security strategy that has clear strategic objectives,sound institutional settings,enhanced economic control,and closer external cooperation.The Japanese government is accelerating its economic and security strategy because of the changing international environment and Japan's own strategic considerations.Japan hopes to achievemany strategic goals such as improved economy and security through its economic and security strategy,but its strategic effect needs to be verified due to the constraints of many factors.
文摘Financial Power and Its Strategic Significance A financial crisis hit Asia in 1997. It was both a predatory monetary war a-gainst developing nations launched by the hedge funds and a scramble for fi-nancial supremacy among the monopoly capital in America, Western Eu-rope and Japan. Indeed, the term "Asian financial crisis" is a misnomer. It can nolonger faithfully reflect the scope and essence of the financial storm. Over the pasttwo years, financial turmoil has visited upon Russia and Brazil and has shaken theentire capitalist economic system. In this crash, while Asian nations have
文摘With the development of economy and the progress of society,people’s living standards are gradually improving,and the requirements for housing are also gradually improving.The development of the real estate industry provides conditions for people’s modern life,and its development meets the needs of China’s socialist development.In such a social background,the future planning of the real estate industry is gradually clear,promoting the steady rise of the real estate economy,which is an important development prospect of the current real estate industry.In this paper,through the analysis of real estate economic security and government control,aiming at the existing problems,put forward some effective measures to promote the advantages of real estate development and the combination of government macro-control to stabilize the healthy development of the real estate industry.
文摘Many heated debates have taken place recently upon the economic security brought about by foreign acquisitions.This should be a good sign,as different views are being aired in contrast to the one uniform voice and hasty generalization has been replaced by ever-intensifying debate,which is indeed historical progress.
文摘The objective of this study is to define agricultural water resources security and its connotation and extension. The definitions of water security, water resources security, and water environment security were summarized, and their relationship was differentiated and analyzed. Based on these, the elements of the conception of agricultural water resources security were hashed and the conception was defined. Agricultural water resources security is the provision of water resource that ensures protection of agriculture against threat, hazards, destruction, and loss. Moreover, the connotation and extension of agricultural water resources security were ascertained. In detail, the connotation of the definition has natural attributes, socioeconomic attributes, and cultural attributes. The extensions of agricultural water resources security include both broad and narrow ones, as well as, food security, agroenvironmental security, agroeconomic security, rural society security, etc. The definition will serve as the frame of reference for developing the researches, limiting the frame of the theory, and founding a appraising system for agricultural water resources security.
文摘Based on the current cloud computing resources security distribution model’s problem that the optimization effect is not high and the convergence is not good, this paper puts forward a cloud computing resources security distribution model based on improved artificial firefly algorithm. First of all, according to characteristics of the artificial fireflies swarm algorithm and the complex method, it incorporates the ideas of complex method into the artificial firefly algorithm, uses the complex method to guide the search of artificial fireflies in population, and then introduces local search operator in the firefly mobile mechanism, in order to improve the searching efficiency and convergence precision of algorithm. Simulation results show that, the cloud computing resources security distribution model based on improved artificial firefly algorithm proposed in this paper has good convergence effect and optimum efficiency.
基金supported by National Natural Science Foundation of China(Grants No.42361144888 and 42401308)National Key Research and Development Program of China(Grant No.2024YFF1309200).
文摘International trade serves as a crucial pathway for enhancing global food security and equality amid severe food crises worldwide.Under globalization,economic development has profoundly influenced food trade,while disparities in food purchasing power among different economic development groups have led to uneven food security outcomes.However,the varying contributions of international trade to food security across these groups remain to be quantitatively elucidated.This study categorized countries into four economic development groups—high,high-medium,medium-low,and low—and examined changes in their food security scores from 2010 to 2019.The cross-group contributions of international trade to food security across these groups were compared.The results revealed that the food security score of the high economic development group was 9.22 times higher than that of the low economic development group.From 2010 to 2019,the high economic development group exhibited a significant upward trend in food security scores,whereas the low economic development group showed a significant decline.Moreover,international trade contributed significantly to both cross-group and within-group food security in the high economic development group,while its contribution to the low economic development group remained negligible.These findings demonstrated that international trade has further widened the food security gap between the high and low economic development groups,and its limited contribution to the low economic development group has failed to reverse the declining trend in their food security scores.This study quantified the divergent impacts of international trade on food security across economic development groups,providing valuable insights for optimizing global food trade policies—particularly in addressing the food security challenges faced by low econominc development group.
文摘Sea lines of communication(SLOCs)security has long been a strategic concern for major powers.Following the establishment of the People’s Republic of China,the country’s focus was on the traditional security aspects of its SLOCs.Since the reform and opening-up era-and especially after the end of the Cold War-China has shifted its emphasis toward economic security.China’s SLOCs security bears on multiple dimensions of a holistic approach to national security,encompassing economic security,the safety of its citizens.
文摘Social security is a product left by economic development. It also has good social security and can effectively promote the development of social security economy. In western countries, social security is when the economy develops to a certain stage. In order to better meet the needs of human resources development, to provide the masses with a living guarantee, to effectively motivate the masses to work actively, and to achieve stable economic development.
基金Supported by Super Rice Program for Agricultural Scientific&Technological Innovation Project of Chinese Academy of Agricultural SciencesSpecial Project of Public Welfare Industry of Ministry of Agriculture(201203029)Special Project for Construction of Modern Agricultural Industrial Technology System(CARS-01-09B)~~
文摘Super rice is an essendal part of China＇s rice production. Through survey on actual situation of 1568 households of rice growers in Heilongjiang, Hunan and Zhejiang provinces, this paper focused on influence of super rice development on increase of China＇s grain yield, influence on increase of rice growers＇ economic in- come, difference in production cost and profit between the North and the South, as well as profit percentage of super rice in production, processing, and sales. It obtained following results： rice price determines rice growers＇ income; expansion of super rice extension area plays a great role in increase of China＇s grain yield; by 2015 and 2020, keeping the yield of other crops not changed, merely the extension of super rice can increase grain for 5 million tons and 11 million tons separately; super rice significantly increases rice growers＇ economic income; for production cost of super rice, the South is higher than the North, and the profit ratio of cost is up to 35.54% on average; with respect of profit in production, processing, and sales, the ratio is 1：2：1.5; with the yield of other crops unchanged, every increase of 1% in area percentage of super rice to rice will additionally produce 1 million tons of grain for China, which is equivalent to saving the yield of 133 300 hm2 farmland and can additional feed 3.5 million people. In view of importance of super rice production, at the same time of strengthening research on super rice variety, it is required to accelerate expanding production area of super rice in suitable areas. Since the development of super rice can support China＇s ration demand of increasing population, China should make effort to realize ＂one yuan for one mu＂ financial subsidy for super rice of main grain production provinces and counties. Besides, China should establish special financial plan for extension of super rice.
文摘Original ecotourism resources mainly refer to natural and human original ecotourism resources, and it＇s of fragility, rarity and irreversibility. As a valuable historic heritage and hnportant tourism resources, it plays a significant role in developing tourism and economy in such areas as the underdeveloped areas, the mountain areas and mimority areas. The tourism resources in the western mountain areas of Guangxi owe ,superiorities and characteristics ＇o their original ecology, Yet, western Guangxi is an ethnic region with fragile karst eco-environment, so it is specialto exploit the tourism resources. The paper defines original eeotourism and analyses the specialties and advantages of the original ecotourism resources as well as thefrailty of the ecotourism resources of the region. The ways of thinking are put forward for safe preservation and sustainable development of the original ecotourism resources, i.e. carrying out measures for the multi-grade protection of heritage resources, setting up a ethnic eco-museum/ ethnic culture eco-park and a gene pool of ethnic cultures, etc.
基金This work was supported by the Knowledge Innovation Program from the Cold and Add Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences （CACX2003102）the Chinese Academy of Sciences （KZCX 1 - 10-03-01）the National Natural Science Foundation of China （40401012）.
文摘Based on the data for meteorology, hydrology, soil, planting, vegetation, and socio-economic development of the irrigation region in the middle reaches of the Heihe River basin, Northwest China, the model of balance of water supply and demand in the region was established, and the security of water resource was assessed, from which the results that the effects of unified management of water resources in the Heihe River basin between Gansu Province and Inner Mongolia on regional hydrology are significant with a decrease in water supply diverted from Heihe River and an increase in groundwater extracted. In addition, it was found that the groundwater level has been steadily decreasing due to over pumping and decrease in recharges. In present year （2003）, the volume of potential groundwater in the irrigation districts is far small because of the groundwater overdraft; even in the particular regions, there is no availability of groundwater resources for use. By 2003, water supply is not sufficient to meet the water demand in the different irrigation districts, the sustainable development and utilization of water resources are not secured, and the water supply crisis occurs in Pingchuan irrigation district. Achieving water security for the sustainable development of society, agriculture, economy, industry, and livelihoods while maintaining or improving the abilities of the management and planning of water resources, determining of the reasonable percentage between water supply and groundwater utilization and water saving in agricultural irrigation are taken into account. If this does not occur, it is feared that the present performance of water development and planning may further aggravate the problem of scarcities of water resources and further damage the fragile ecological system.
文摘The accelerating global energy transition,driven by climate imperatives and technological advancements,demands fundamen-tal transformations in power systems.Smart grids,characterized by cyber-physical integration,distributed renewable resources,and data-driven intelligence,have emerged as the backbone of this evolution.This convergence,however,introduces unprecedented complexities in resilience,security,stability,and market operation.This special issue presents five pivotal studies addressing these interconnected challenges,offering novel methodologies and insights to advance the efficiency,resilience,and sustainability of modern power systems.
文摘After the analysis of food security of Shandong Province since 1990s, based on the change of grain output and per unit grain yield, it was considered that food production of Shandong Province was generally stable; through comparing the proportion of per capita possession of grains and per unit grain yield of Shandong Province in the whole country, it revealed that they were higher than the national average level. On this basis, the relationship between land-water resources and food security had been analyzed, and it summarized that Shandong water resources were insufficient, agricultural water was not enough and water had been seriously polluted; and that cultivated area was large and the overall quality was high. Meanwhile, it had analyzed the spatial pattern of land-water resources and the loss of water and soil. Finally, suggestions for the sustainable use of land-water resources in Shandong Province based on food security had been proposed. It should enhance the construction of basic agricultural facilities and implement united dispatching of multiple water resources; strengthen the supervision of cultivated land resources and comprehensively develop reserve resources of cultivated lands; and intensify the treatment of land-water resources and prevention of the loss of water and soil in key areas.
基金Supported by the National Basic Research Program of China under Grant No 2013CB338002the National Natural Science Foundation of China under Grant Nos 11304397 and 61505261
文摘The quantum key distribution （QKD） allows two parties to share a secret key by typically making use of a one-way quantum channel. Howevery the two-way QKD has its own unique advantages, which means the two-way QKD has become a focus recently. To improve the practieM performance of the two-way QKD, we present a security analysis of a two-way QKD protocol based on the decoy method with heralded single-photon sources （HSPSs）. We make use of two approaches to calculate the yield and the quantum bit error rate of single-photon and two-photon pulses. Then we present the secret key generation rate based on the GLLP formula. The numerical simulation shows that the protocol with HSPSs has an advantage in the secure distance compared with weak coherent state sources. In addition, we present the final secret key by considering the statistical fluctuation of the yield generation rate of the LM05 protocol with finite resources and the error rate.
基金This research was funded by the General Program of Natural Science Foundation of Hunan Province,China(2020JJ4503)the Hunan Provincial Innovation Foundation for Postgraduate,China(CX20190878)the Key Program of the Department of Education of Hunan Province,China(19A405).
文摘Clarifying the relationship between social security and economic development is helpful to realize the sustainable social security system and the stable function of sustainable economic development.In this paper,the entropy method,coupling coordination degree,standard deviation ellipse model,and spatial autocorrelation were used to study the spatial-temporal characteristics of coupling coordination of social security and economic development in China from 2002 to 2018.The results indicate that the relationship between social security and economic development in China has been gradually strengthened in the process of mutual adaptation and common development.The benign interaction between the two was unstable,though the coupling coordination degree gradually transitioned to the primary coupling coordination type.Besides,from a spatial perspective,first,the coupling coordination degree of social security and economic development in China contracted in the east-west and north-south directions,and the coupling coordination clustered in the central region in this period;second,the coupling coordination degree generally presented a positive spatial autocorrelation,and regions with similar coupling coordination degrees were in a state of agglomeration;finally,the hot spots clumped together to form a continuous area in the eastern coastal area while the cold spots expanded toward the northwest and northeast.Furthermore,the random distribution areas exhibited a trend of contraction.
基金supported by the Chengdu Philosophy and Social Science Planning Project[Grant No.2022C05]National Natural Science Foundation of China[Grant No.71904158].
文摘Developing low-carbon and efficient power systems is critical for energy security in the global warming context.We address this issue by focusing on the productivity impact of a decarbonization policy in China’s thermal power sector—namely,the“Constructing Large Units and Restricting Small Ones”(CLRS)initiative.Utilizing a resource misallocation model,we construct a new theoretical framework to distinguish between technical and allocative efficiency and analyze productivity using plant-level data.The results indicate that the CLRS policy has significantly improved the allocative and technical efficiency of China’s coal-fired power sector,thereby ensuring power security.The closure of outdated and highly distorted small coal-fired units,which have been replaced by technologically advanced large units,primarily drives the enhanced efficiency.The policy’s effects are most pronounced in large-scale power plants and those with high coal combustion efficiency.Furthermore,a comparison of power plants’productivity distribution before and after policy implementation reveals that the CLRS policy not only enhances capital productivity in the coal-fired power sector but also increases rational labor allocation.Our findings have important policy implications for developing countries vis-à-vis building efficient and stable power systems amid climate change.
