[Objective] The aim was to study the effects of water supply and consumption on water saving and drought resistance. [Method] Controlling field experiment was conducted to explore water balance between supply and dema...[Objective] The aim was to study the effects of water supply and consumption on water saving and drought resistance. [Method] Controlling field experiment was conducted to explore water balance between supply and demand in paddy fields in hilly regions in Sichuan Province. [Result] Rainfall in hilly areas was 3 611.10 m3/hm2; water for irrigation was 6 299.25 m3/hm2; evapotranspiration of rice was 6 424.95 m3/hm2; deep leakage was 2 459.55 m3/hm2; overflowing amount was 1 026.00 m3/hm2. In addition, water consumption totaled 8 884.50 m3/hm2 during rice production; water use was 0.99 kg/m3 and use efficiency of irrigated water was 1.40 kg/m3. [Conclusion] Water supply and consumption should be further organized to save water and fight against drought in hilly areas in Sichuan Province.展开更多
The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consump...The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consumption in development and utilization is 43. 33x 10~8m^3. Water supply and demand reach a balance on the recent level of production, but loss ofevaporation and evapotranspiration is as much as 25. 69 x 1010~8m^3. So net use efficiency of waterresources is 59% Based on analyzing balance between water and land considering ecologicalenvironment at present, there exists the serious water shortage in the Shiyang River system whereirrigation lands have overloaded. There is a comparative balance between supply and demand of waterresource in the Heihe River system; and the Sule River system has some surplus water to extendirrigation land. Use of agriculture water accounts for 83. 3% and ecological forest and grass for 6.9% . The Hexi Corridor still has a great potential for water saving in agriculture production.Water-saving efficiency of irrigation is about 10% by using such traditional technologies as furrowand border-dike irrigation and small check irrigation, and water-saving with plastic film cover andtechniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigatedwater. Incremental irrigation area for water-saving potential in the Hexi Corridor has beenestimated as 56% - 197% to original irrigation area. So the second water sources can be developedfrom water saving agriculture in the Hexi Corridor under Development of the Western Part of China inlarge scale. This potential can be realized step by step through developing the water-savingmeasures, improving the ecological condition of oasis agriculture, and optimizing allocation ofwater resources in three river systems.展开更多
This paper intends to complete the primary logistics planning of oil products under the imbalance of supply and demand. An integrated mathematical programming model is developed to simultaneously find the balance betw...This paper intends to complete the primary logistics planning of oil products under the imbalance of supply and demand. An integrated mathematical programming model is developed to simultaneously find the balance between supply and demand, and optimize the logistics scheme. The model takes minimum logistics cost and resource adjustment cost as the objective function, and takes supply and demand capacity, transportation capacity, mass balance, and resource adjustment rules as constraints.Three adjustment rules are considered in the model, including resource adjustment within oil suppliers,within oil consumers, and between oil consumers. The model is tested on a large-scale primary logistics of a state-owned petroleum enterprise, involving 37 affiliated refineries, 31 procurement departments,286 market depots and dedicated consumers. After the unified optimization, the supply and demand imbalance is eased by 97% and the total cost is saved by 7%, which proves the effectiveness and applicability of the proposed model.展开更多
Promoting agricultural production and ensuring the supply of agricultural products has always been the main task of agricultural development in China,but the agricultural production in China has not yet been combined ...Promoting agricultural production and ensuring the supply of agricultural products has always been the main task of agricultural development in China,but the agricultural production in China has not yet been combined with the Chinese residents' dietary needs to formulate reasonable development goals,with a certain blindness in production. According to the dietary standards in The Dietary Guidelines for Chinese Residents developed by the Chinese Nutrition Society,we calculate the demand of various types of agricultural products in China under the conditions of balanced diet. In comparison with the output of various types of agricultural products in China at present,we find that the output of most of agricultural products in China has exceeded the reasonable demand of the Chinese residents under the conditions of balanced diet. Therefore,adjusting the agricultural production structure in China and advocating balanced diet has become an important way to solve the problem of balance between supply and demand of agricultural products.展开更多
As the population ages and family miniaturization trend intensified, pension agency demand for service personnel increased significantly, while the supply of human resources is inadequate. This article is based on the...As the population ages and family miniaturization trend intensified, pension agency demand for service personnel increased significantly, while the supply of human resources is inadequate. This article is based on the present situation of the imbalance between supply and demand of human resources, analysis of causes of the contradiction between them. Then put forward some suggestions on this basis, such as increase government financial input, build a professional medical personnel training system, develop volunteers and improve employees' rights protection mechanism.展开更多
Based on the analysis of China’s grain production and demand quality grade, this paper uses the non-equidistance GM (1,1) model and the inference algorithm to predict the structural balance of the supply and demand g...Based on the analysis of China’s grain production and demand quality grade, this paper uses the non-equidistance GM (1,1) model and the inference algorithm to predict the structural balance of the supply and demand grades of China’s four major grain crops. The results show that the supply and demand for wheat, corn and rice can maintain a quantitative balance. While, it’s difficult to achieve a quality grade balance in wheat and rice and keep a supply and demand balance in terms of quantity and quality of soybean. Simultaneously, the supply of premium grade corn is greater than the demand. The analysis and prediction results can reflect the existing structural balance matter of grain supply and demand at different quality grades in China, and provide theoretical basis for governments to formulate relevant policies.展开更多
The paper had analyzed the technology, maintenance and recognition of vertical greening in urban space, and proposed a solution for balance water supply for balconies and streetlights, that is, magnetic auxiliary shal...The paper had analyzed the technology, maintenance and recognition of vertical greening in urban space, and proposed a solution for balance water supply for balconies and streetlights, that is, magnetic auxiliary shallow water level controller, the patent of which had been applied. Magnetic auxiliary shallow water level controller had met water supply of some special parts of urban vertical greening and was sure to accelerate urban vertical greening.展开更多
Objective: To evaluate the effects of various degrees of hyperventilation on balance of cerebral oxygensupply and consumption during intravenous general anesthesia with jugular venous oxygen saturation monitoringMetbo...Objective: To evaluate the effects of various degrees of hyperventilation on balance of cerebral oxygensupply and consumption during intravenous general anesthesia with jugular venous oxygen saturation monitoringMetbods: Sixty-six patients with supratentorial tumor undergoing intravenous general anesthesia for brain surgerywere randomly divided into three groups. In group Ⅰ, Ⅱ and Ⅲ, end-tidal pressure of Co2(PETCO2) were maintained at 3. 5, 4. 0 and 4. 5 kPa respectively. Radial arterial blood samples and jugular bulb blood samples weretaken synchronously at 60 min after hyperventilation to measure jugular venous oxygen saturation (SjvO2), cerebral extraction of oxygen (CEO2) and cerebral arteriovenous oxygen content difference (AVDO2) were calculatedResults: In group Ⅰ after hyperventilation, SjvO, and jugular venous oxygen content (CjvO2) were decreasedmarkedly while CEO2 was increased significantly, which was different significantly compared with the baseline andcorresponding value in group Ⅱ and Ⅲ (P<0. 05). After hyperventilation in group, and, SjvO2 CjvO2, CEO2and AVDO, remained unchanged. Conclusion: This study shows that sustained excessive hyperventilation (PETCO23.5 kPa) may account for the less favorable cerebral oxygen supply and consumption balance and maintained PETCO, at 4. 0~4. 5 kPa was optimal hyperventilation for brain surgery anesthesia.展开更多
This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)f...This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.展开更多
In operations research, the transportation problem (TP) is among the earliest and most effective applications of the linear programming problem. Unbalanced transportation problems reflect the reality of supply chain a...In operations research, the transportation problem (TP) is among the earliest and most effective applications of the linear programming problem. Unbalanced transportation problems reflect the reality of supply chain and logistics situations where the available supply of goods may not precisely match the demand at different locations. To deal with an unbalanced transportation problem (UTP), it is essential first to convert it into a balanced transportation problem (BTP) to find an initial basic feasible solution (IBFS) and hence the optimal solution. The present paper is concerned with introducing a new approach to convert an unbalanced transportation problem into a balanced one and as a consequence to obtain optimum total transportation cost. Numerical examples are provided to demonstrate the suggested method.展开更多
Compared with what they are under close economy, balance of payments and money supply under open economy have their own features in composition, structure, characteristics and targets. A mathematic model of compositio...Compared with what they are under close economy, balance of payments and money supply under open economy have their own features in composition, structure, characteristics and targets. A mathematic model of composition and structure of GNP is fabricated in this paper, and then the paper analyzes the impacts upon money supply and exchange rate that open economy has. Finally, the relationship among the independence of monetary policies, the stability of foreign exchange rate and the free circulation is discussed.展开更多
A supply chain resilience model is established based on the biological cellular resilience theory to analyze the impact of the supplier relationship on supply chain resilience. A scenario where the market demand is ch...A supply chain resilience model is established based on the biological cellular resilience theory to analyze the impact of the supplier relationship on supply chain resilience. A scenario where the market demand is changed suddenly by some undesired events is considered. The results reveal that enhancing collaboration with a more resilient supplier can significantly improve supply chain resilience and reduce supply chain losses. It is also found that enhancing the supplier relationship can significantly benefit supply chain resilience if the collaborative intensity is relatively low, and it has less effect if supply chain members have already collaborated closely. Thus, enhancing the supplier relationship to a limited intensity is a relatively effective and economic method to strengthen supply chain resilience.展开更多
A single product closed-loop supply chain that satisfies an uncertain market demand with original and remanufactured products is considered.The yield of the recovery process is random and depends on the acquisition pr...A single product closed-loop supply chain that satisfies an uncertain market demand with original and remanufactured products is considered.The yield of the recovery process is random and depends on the acquisition price offered for the end-of-life products.In such a stochastic setting,a firm needs to make production and procurement decisions so that the total expected profit is maximized.Both centralized and decentralized models are established depending on the party collecting the returns.The optimal acquisition price and production quantities of original and remanufactured products are determined for the firm.The contracts to coordinate the decentralized systems are chosen and the optimal contract parameters are determined.A computational experiment is given to show the effects of recovery parameters on the system performance.Results show that the recovery parameters have a high impact on the profitability of the manufacturer in the centralized model and on that of the collection agency in the decentralized model.展开更多
Using the data of wheat varieties with year-sown area of 6 666.7 hm^2 or more from 1982 to 2006 in China, the evolution of wheat varieties was studied from both supply and demand. Results showed that although various ...Using the data of wheat varieties with year-sown area of 6 666.7 hm^2 or more from 1982 to 2006 in China, the evolution of wheat varieties was studied from both supply and demand. Results showed that although various characters of wheat varieties grown by peasants in production were improved obviously in China, the demand for variety yield was still the main demand by peasants; there was no significant difference between the supply and demand of crude protein content by peasants; the demand for disease resistance has been lower than the supply recently; the demand for full growth stage at every stage was less than the supply; and while there was a larger demand for plant height by peasants.展开更多
[Objective] The purpose of this study is to estimate water supply and demand, which can provide a basis for how to allocate rationally water resources in Hotan Oasis. [Method] The water supply and demand in Hotan Oasi...[Objective] The purpose of this study is to estimate water supply and demand, which can provide a basis for how to allocate rationally water resources in Hotan Oasis. [Method] The water supply and demand in Hotan Oasis in the next15 years were calculated according to water-soil balance. [Result] When the runoff of Hotan River is at a probability of 50%(P=50 for short), the total water resource is 50.57×10^8m^3, and there is only 33.13×10^8m^3available for social and economics,but there would be a need of 33.44×10^8and 36.06×10^8m^3, and the water shortage would be 1.31 ×10^8and 2.93 ×10^8m^3in 2020 and 2030 respectively. When P =75,the total water resource is 44.30×10^8m^3, there is only 29.39×10^8m^3water available for social and economics. However, there would be a need of 31.43 ×10^8and33.11×10^8m^3, and the water shortage would be 2.04×10^8and 3.72×10^8m^3in 2020 and 2030, respectively. [Conclusion] The problem of water shortage would be serious over the next 15 years, and the fragile ecosystem would be destroyed dramatically with the large-scale land reclamation against natural laws. Hence, the effective policies and measures should be taken timely to prohibit reclamation and to cope with ongoing water shortage, based on the water supply and demand estimation under the background of climate change.展开更多
Along with the coming of the low-carbon era, people have paid more and more attention to the natural environment and eco-tourism will embrace a huge development. From the perspectives of the market relationship of sup...Along with the coming of the low-carbon era, people have paid more and more attention to the natural environment and eco-tourism will embrace a huge development. From the perspectives of the market relationship of supply-demand in economics and of field competition in physics, this paper has discussed upon the present status of the spatial structure of eco-tourism, and analyzed the relationship between supply-demand and field, in order to clarify the direction for the balance between supply and demand in the field and to guide eco-tourism to the way of sustainable development.展开更多
Bulk mineral resources of iron ores, copper ores, bauxite, lead ores, zinc ores and potassium salt play a pivotal role on the world's and China's economic development. This study analyzed and predicted their resourc...Bulk mineral resources of iron ores, copper ores, bauxite, lead ores, zinc ores and potassium salt play a pivotal role on the world's and China's economic development. This study analyzed and predicted their resources base and potential, development and utilization and their world's and China's supply and demand situation in the future 20 years. The supply and demand of these six bulk mineral products are generally balanced, with a slight surplus, which will guarantee the stability of the international mineral commodity market supply. The six mineral resources (especially iron ores and copper ores) are abundant and have a great potential, and their development and utilization scale will gradually increase. Till the end of 2014, the reserve- production ratio of iron, copper, bauxite, lead, zinc ores and potassium salt was 95 years, 42 years, 100 years, 17 years, 37 years and 170 years, respectively. Except lead ores, the other five types all have reserve-production ratio exceeding 20 years, indicative of a high resources guarantee degree. If the utilization of recycled metals is counted in, the supply of the world's six mineral products will exceed the demand in the future twenty years. In 2015-2035, the supply of iron ores, refined copper, primary aluminum, refined lead, zinc and potassium salt will exceed their demand by 0.4-0.7 billion tons (Gt), 5.0-6.0 million tons (Mt), 1.1-8.9 Mt, 1.0-2.0 Mt, 1.2-2.0 Mt and 4.8-5.6 Mt, respectively. It is predicted that there is no problem with the supply side of bulk mineral products such as iron ores, but local or structural shortage may occur because of geopolitics, monopoly control, resources nationalism and trade friction. Affected by China's compressed industrialized development model, the demand of iron ores (crude steel), potassium salt, refined lead, refined copper, bauxite (primary aluminum) and zinc will gradually reach their peak in advance. The demand peak of iron ores (crude steel) will reach around 2015, 2016 for potassium salt, 2020 for refined lead, 2021 for bauxite (primary aluminum), 2022 for refined copper and 2023 for zinc. China's demand for iron ores (crude steel), bauxite (primary aluminum) and zinc in the future 20 years will decline among the world's demand, while that for refined copper, refined lead and potassium salt will slightly increase. The demand for bulk mineral products still remains high. In 2015-2035, China's accumulative demand for iron ores (crude steel) will be 20.313 Gt (13.429 Gt), 0.304 Gt for refined copper, 2.466 Gt (0.616 Gt) of bauxite (primary aluminum), 0.102 Gt of refined lead, 0.138 Gt of zinc and 0.157 Gt of potassium salt, and they account for the world's YOY (YOY) accumulative demand of 35.17%, 51.09%, 48.47%, 46.62%, 43.95% and 21.84%, respectively. This proportion is 49.40%, 102.52%, 87.44%, 105.65%, 93.62% and 106.49% of that in 2014, respectively. From the supply side of China's bulk mineral resources, it is forecasted that the accumulative supply of primary (mine) mineral products in 2015-2035 is 4.046 Gt of iron ores, 0.591 Gt of copper, 1.129 Gt of bauxite, 63.661 Mt of (mine) lead, 0.109 Gt of (mine) zinc and 0.128 Gt of potassium salt, which accounts for 8.82%, 13.92%, 26.67%, 47.09%, 33.04% and 15.56% of the world's predicted YOY production, respectively. With the rapid increase in the smelting capacity of iron and steel and alumina, the rate of capacity utilization for crude steel, refined copper, alumina, primary aluminum and refined lead in 2014 was 72.13%, 83.63%, 74.45%, 70.76% and 72.22%, respectively. During 2000-2014, the rate of capacity utilization for China's crude steel and refined copper showed a generally fluctuating decrease, which leads to an insufficient supply of primary mineral products. It is forecasted that the supply insufficiency of iron ores in 2015-2035 is 17.44 Gt, 0.245 Gt of copper in copper concentrates, 1.337 Gt of bauxite, 38.44 Mt of lead in lead concentrates and 29.19 Mt of zinc in zinc concentrates. China has gradually raised the utilization of recycled metals, which has mitigated the insufficient supply of primary metal products to some extent. It is forecasted that in 2015-2035 the accumulative utilization amount of steel scrap (iron ores) is 3.27 Gt (5.08 Gt), 70.312 Mt of recycled copper, 0.2 Gt of recycled aluminum, 48 Mt of recycled lead and 7.7 Mt of recycled zinc. The analysis on the supply and demand situation of China's bulk mineral resources in 2015-2035 suggests that the supply-demand contradiction for these six types of mineral products will decrease, indicative of a generally declining external dependency. If the use of recycled metal amount is counted in, the external dependency of China's iron, copper, bauxite, lead, zinc and potassium salt will be 79%, 65%, 26%, 8%, 16% and 18% in 2014, respectively. It is predicted that this external dependency will decrease to 62%, 64%, 20%, -0.93%, 16% and 14% in 2020, respectively, showing an overall decreasing trend. We propose the following suggestions correspondingly. (1) The demand peak of China's crude steel and potassium salt will reach during 2015-2023 in succession. Mining transformation should be planned and deployed in advance to deal with the arrival of this demand peak. (2) The supply-demand contradiction of China's bulk mineral resources will mitigate in the future 20 years, and the external dependency will decrease accordingly. It is suggested to adjust the mineral resources management policies according to different minerals and regions, and regulate the exploration and development activities. (3) China should further establish and improve the forced mechanism of resolving the smelting overcapacity of steel, refined copper, primary aluminum, lead and zinc to really achieve the goal of "reducing excess production capacity". (4) In accordance with the national strategic deployment of "One Belt One Road", China should encourage the excess capacity of steel, copper, alumina and primary aluminum enterprises to transfer to those countries or areas with abundant resources, high energy matching degree and relatively excellent infrastructure. Based on the national conditions, mining condition and geopolitics of the resources countries, we will gradually build steel, copper, aluminum and lead-zinc smelting bases, and potash processing and production bases, which will promote the excess capacity to transfer to the overseas orderly. (5) It is proposed to strengthen the planning and management of renewable resources recycling and to construct industrial base of renewable metal recycling. (6) China should promote the comprehensive development and utilization of paragenetic and associated mineral species to further improve the comprehensive utilization of bulk mineral resources.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
Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too i...Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too ideal to obtain the network equilibrium state in practical market competition.In order to achieve equilibrium,we introduce revenue sharing contract into a supply chain network equilibrium model with random demand in this paper.Then,we investigate the influence on this network equilibrium state from demand disruptions caused by unexpected emergencies.When demand disruptions happen,the supply chain network equilibrium state will be broken and change to a new one,so the decision makers need to adjust the contract parameters to achieve the new coordinated state through bargaining.Finally,a numerical example with a sudden demand increase as a result of emergent event is provided for illustrative purposes.展开更多
文摘[Objective] The aim was to study the effects of water supply and consumption on water saving and drought resistance. [Method] Controlling field experiment was conducted to explore water balance between supply and demand in paddy fields in hilly regions in Sichuan Province. [Result] Rainfall in hilly areas was 3 611.10 m3/hm2; water for irrigation was 6 299.25 m3/hm2; evapotranspiration of rice was 6 424.95 m3/hm2; deep leakage was 2 459.55 m3/hm2; overflowing amount was 1 026.00 m3/hm2. In addition, water consumption totaled 8 884.50 m3/hm2 during rice production; water use was 0.99 kg/m3 and use efficiency of irrigated water was 1.40 kg/m3. [Conclusion] Water supply and consumption should be further organized to save water and fight against drought in hilly areas in Sichuan Province.
文摘The Hexi Corridor is an important base of agriculture development inNorthwest China. According to recent statistics, there are 65. 94 x 10~8m^3 of water resourcesavailable in the Hexi Corridor. At present, net consumption in development and utilization is 43. 33x 10~8m^3. Water supply and demand reach a balance on the recent level of production, but loss ofevaporation and evapotranspiration is as much as 25. 69 x 1010~8m^3. So net use efficiency of waterresources is 59% Based on analyzing balance between water and land considering ecologicalenvironment at present, there exists the serious water shortage in the Shiyang River system whereirrigation lands have overloaded. There is a comparative balance between supply and demand of waterresource in the Heihe River system; and the Sule River system has some surplus water to extendirrigation land. Use of agriculture water accounts for 83. 3% and ecological forest and grass for 6.9% . The Hexi Corridor still has a great potential for water saving in agriculture production.Water-saving efficiency of irrigation is about 10% by using such traditional technologies as furrowand border-dike irrigation and small check irrigation, and water-saving with plastic film cover andtechniques of advanced sprinkler and drip/micro irrigation etc. can save more than 60% of irrigatedwater. Incremental irrigation area for water-saving potential in the Hexi Corridor has beenestimated as 56% - 197% to original irrigation area. So the second water sources can be developedfrom water saving agriculture in the Hexi Corridor under Development of the Western Part of China inlarge scale. This potential can be realized step by step through developing the water-savingmeasures, improving the ecological condition of oasis agriculture, and optimizing allocation ofwater resources in three river systems.
基金partially supported by the National Natural Science Foundation of China (51874325)the Science Foundation of China University of PetroleumBeijing (2462021BJRC009)。
文摘This paper intends to complete the primary logistics planning of oil products under the imbalance of supply and demand. An integrated mathematical programming model is developed to simultaneously find the balance between supply and demand, and optimize the logistics scheme. The model takes minimum logistics cost and resource adjustment cost as the objective function, and takes supply and demand capacity, transportation capacity, mass balance, and resource adjustment rules as constraints.Three adjustment rules are considered in the model, including resource adjustment within oil suppliers,within oil consumers, and between oil consumers. The model is tested on a large-scale primary logistics of a state-owned petroleum enterprise, involving 37 affiliated refineries, 31 procurement departments,286 market depots and dedicated consumers. After the unified optimization, the supply and demand imbalance is eased by 97% and the total cost is saved by 7%, which proves the effectiveness and applicability of the proposed model.
基金Supported by the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Public-interest Research Institutes (202-23)
文摘Promoting agricultural production and ensuring the supply of agricultural products has always been the main task of agricultural development in China,but the agricultural production in China has not yet been combined with the Chinese residents' dietary needs to formulate reasonable development goals,with a certain blindness in production. According to the dietary standards in The Dietary Guidelines for Chinese Residents developed by the Chinese Nutrition Society,we calculate the demand of various types of agricultural products in China under the conditions of balanced diet. In comparison with the output of various types of agricultural products in China at present,we find that the output of most of agricultural products in China has exceeded the reasonable demand of the Chinese residents under the conditions of balanced diet. Therefore,adjusting the agricultural production structure in China and advocating balanced diet has become an important way to solve the problem of balance between supply and demand of agricultural products.
文摘As the population ages and family miniaturization trend intensified, pension agency demand for service personnel increased significantly, while the supply of human resources is inadequate. This article is based on the present situation of the imbalance between supply and demand of human resources, analysis of causes of the contradiction between them. Then put forward some suggestions on this basis, such as increase government financial input, build a professional medical personnel training system, develop volunteers and improve employees' rights protection mechanism.
文摘Based on the analysis of China’s grain production and demand quality grade, this paper uses the non-equidistance GM (1,1) model and the inference algorithm to predict the structural balance of the supply and demand grades of China’s four major grain crops. The results show that the supply and demand for wheat, corn and rice can maintain a quantitative balance. While, it’s difficult to achieve a quality grade balance in wheat and rice and keep a supply and demand balance in terms of quantity and quality of soybean. Simultaneously, the supply of premium grade corn is greater than the demand. The analysis and prediction results can reflect the existing structural balance matter of grain supply and demand at different quality grades in China, and provide theoretical basis for governments to formulate relevant policies.
文摘The paper had analyzed the technology, maintenance and recognition of vertical greening in urban space, and proposed a solution for balance water supply for balconies and streetlights, that is, magnetic auxiliary shallow water level controller, the patent of which had been applied. Magnetic auxiliary shallow water level controller had met water supply of some special parts of urban vertical greening and was sure to accelerate urban vertical greening.
文摘Objective: To evaluate the effects of various degrees of hyperventilation on balance of cerebral oxygensupply and consumption during intravenous general anesthesia with jugular venous oxygen saturation monitoringMetbods: Sixty-six patients with supratentorial tumor undergoing intravenous general anesthesia for brain surgerywere randomly divided into three groups. In group Ⅰ, Ⅱ and Ⅲ, end-tidal pressure of Co2(PETCO2) were maintained at 3. 5, 4. 0 and 4. 5 kPa respectively. Radial arterial blood samples and jugular bulb blood samples weretaken synchronously at 60 min after hyperventilation to measure jugular venous oxygen saturation (SjvO2), cerebral extraction of oxygen (CEO2) and cerebral arteriovenous oxygen content difference (AVDO2) were calculatedResults: In group Ⅰ after hyperventilation, SjvO, and jugular venous oxygen content (CjvO2) were decreasedmarkedly while CEO2 was increased significantly, which was different significantly compared with the baseline andcorresponding value in group Ⅱ and Ⅲ (P<0. 05). After hyperventilation in group, and, SjvO2 CjvO2, CEO2and AVDO, remained unchanged. Conclusion: This study shows that sustained excessive hyperventilation (PETCO23.5 kPa) may account for the less favorable cerebral oxygen supply and consumption balance and maintained PETCO, at 4. 0~4. 5 kPa was optimal hyperventilation for brain surgery anesthesia.
文摘This paper introduces an innovative approach to the synchronized demand-capacity balance with special focus on sector capacity uncertainty within a centrally controlled collaborative air traffic flow management(ATFM)framework.Further with previous study,the uncertainty in capacity is considered as a non-negligible issue regarding multiple reasons,like the impact of weather,the strike of air traffic controllers(ATCOs),the military use of airspace and the spatiotemporal distribution of nonscheduled flights,etc.These recessive factors affect the outcome of traffic flow optimization.In this research,the focus is placed on the impact of sector capacity uncertainty on demand and capacity balancing(DCB)optimization and ATFM,and multiple options,such as delay assignment and rerouting,are intended for regulating the traffic flow.A scenario optimization method for sector capacity in the presence of uncertainties is used to find the approximately optimal solution.The results show that the proposed approach can achieve better demand and capacity balancing and determine perfect integer solutions to ATFM problems,solving large-scale instances(24 h on seven capacity scenarios,with 6255 flights and 8949 trajectories)in 5-15 min.To the best of our knowledge,our experiment is the first to tackle large-scale instances of stochastic ATFM problems within the collaborative ATFM framework.
文摘In operations research, the transportation problem (TP) is among the earliest and most effective applications of the linear programming problem. Unbalanced transportation problems reflect the reality of supply chain and logistics situations where the available supply of goods may not precisely match the demand at different locations. To deal with an unbalanced transportation problem (UTP), it is essential first to convert it into a balanced transportation problem (BTP) to find an initial basic feasible solution (IBFS) and hence the optimal solution. The present paper is concerned with introducing a new approach to convert an unbalanced transportation problem into a balanced one and as a consequence to obtain optimum total transportation cost. Numerical examples are provided to demonstrate the suggested method.
文摘Compared with what they are under close economy, balance of payments and money supply under open economy have their own features in composition, structure, characteristics and targets. A mathematic model of composition and structure of GNP is fabricated in this paper, and then the paper analyzes the impacts upon money supply and exchange rate that open economy has. Finally, the relationship among the independence of monetary policies, the stability of foreign exchange rate and the free circulation is discussed.
基金The National Natural Science Foundation of China(No.71171050,71390333)the National Key Technology R&D Program of China during the 12th Five-Year Plan Period(No.2013BAD19B05)+1 种基金the Scientific Innovation Research of College Graduates in Jiangsu Province(No.CXZZ12_0107)the Scientific Research Foundation of Graduate School of Southeast University(No.YBJJ1237)
文摘A supply chain resilience model is established based on the biological cellular resilience theory to analyze the impact of the supplier relationship on supply chain resilience. A scenario where the market demand is changed suddenly by some undesired events is considered. The results reveal that enhancing collaboration with a more resilient supplier can significantly improve supply chain resilience and reduce supply chain losses. It is also found that enhancing the supplier relationship can significantly benefit supply chain resilience if the collaborative intensity is relatively low, and it has less effect if supply chain members have already collaborated closely. Thus, enhancing the supplier relationship to a limited intensity is a relatively effective and economic method to strengthen supply chain resilience.
基金The National Natural Science Foundation of China(No.70772059)
文摘A single product closed-loop supply chain that satisfies an uncertain market demand with original and remanufactured products is considered.The yield of the recovery process is random and depends on the acquisition price offered for the end-of-life products.In such a stochastic setting,a firm needs to make production and procurement decisions so that the total expected profit is maximized.Both centralized and decentralized models are established depending on the party collecting the returns.The optimal acquisition price and production quantities of original and remanufactured products are determined for the firm.The contracts to coordinate the decentralized systems are chosen and the optimal contract parameters are determined.A computational experiment is given to show the effects of recovery parameters on the system performance.Results show that the recovery parameters have a high impact on the profitability of the manufacturer in the centralized model and on that of the collection agency in the decentralized model.
文摘Using the data of wheat varieties with year-sown area of 6 666.7 hm^2 or more from 1982 to 2006 in China, the evolution of wheat varieties was studied from both supply and demand. Results showed that although various characters of wheat varieties grown by peasants in production were improved obviously in China, the demand for variety yield was still the main demand by peasants; there was no significant difference between the supply and demand of crude protein content by peasants; the demand for disease resistance has been lower than the supply recently; the demand for full growth stage at every stage was less than the supply; and while there was a larger demand for plant height by peasants.
基金Supported by the National Basic Research Program of China(973 Program,2010CB955905)the Fund of Chengde Municipal Finance Bureau(CZ2013004)~~
文摘[Objective] The purpose of this study is to estimate water supply and demand, which can provide a basis for how to allocate rationally water resources in Hotan Oasis. [Method] The water supply and demand in Hotan Oasis in the next15 years were calculated according to water-soil balance. [Result] When the runoff of Hotan River is at a probability of 50%(P=50 for short), the total water resource is 50.57×10^8m^3, and there is only 33.13×10^8m^3available for social and economics,but there would be a need of 33.44×10^8and 36.06×10^8m^3, and the water shortage would be 1.31 ×10^8and 2.93 ×10^8m^3in 2020 and 2030 respectively. When P =75,the total water resource is 44.30×10^8m^3, there is only 29.39×10^8m^3water available for social and economics. However, there would be a need of 31.43 ×10^8and33.11×10^8m^3, and the water shortage would be 2.04×10^8and 3.72×10^8m^3in 2020 and 2030, respectively. [Conclusion] The problem of water shortage would be serious over the next 15 years, and the fragile ecosystem would be destroyed dramatically with the large-scale land reclamation against natural laws. Hence, the effective policies and measures should be taken timely to prohibit reclamation and to cope with ongoing water shortage, based on the water supply and demand estimation under the background of climate change.
文摘Along with the coming of the low-carbon era, people have paid more and more attention to the natural environment and eco-tourism will embrace a huge development. From the perspectives of the market relationship of supply-demand in economics and of field competition in physics, this paper has discussed upon the present status of the spatial structure of eco-tourism, and analyzed the relationship between supply-demand and field, in order to clarify the direction for the balance between supply and demand in the field and to guide eco-tourism to the way of sustainable development.
基金supported by the China geological survey subproject of Dynamic Track and Evaluation of the Guarantee Degree of the Main Mineral Resources in China(No.121201103000150112,N1618-8)
文摘Bulk mineral resources of iron ores, copper ores, bauxite, lead ores, zinc ores and potassium salt play a pivotal role on the world's and China's economic development. This study analyzed and predicted their resources base and potential, development and utilization and their world's and China's supply and demand situation in the future 20 years. The supply and demand of these six bulk mineral products are generally balanced, with a slight surplus, which will guarantee the stability of the international mineral commodity market supply. The six mineral resources (especially iron ores and copper ores) are abundant and have a great potential, and their development and utilization scale will gradually increase. Till the end of 2014, the reserve- production ratio of iron, copper, bauxite, lead, zinc ores and potassium salt was 95 years, 42 years, 100 years, 17 years, 37 years and 170 years, respectively. Except lead ores, the other five types all have reserve-production ratio exceeding 20 years, indicative of a high resources guarantee degree. If the utilization of recycled metals is counted in, the supply of the world's six mineral products will exceed the demand in the future twenty years. In 2015-2035, the supply of iron ores, refined copper, primary aluminum, refined lead, zinc and potassium salt will exceed their demand by 0.4-0.7 billion tons (Gt), 5.0-6.0 million tons (Mt), 1.1-8.9 Mt, 1.0-2.0 Mt, 1.2-2.0 Mt and 4.8-5.6 Mt, respectively. It is predicted that there is no problem with the supply side of bulk mineral products such as iron ores, but local or structural shortage may occur because of geopolitics, monopoly control, resources nationalism and trade friction. Affected by China's compressed industrialized development model, the demand of iron ores (crude steel), potassium salt, refined lead, refined copper, bauxite (primary aluminum) and zinc will gradually reach their peak in advance. The demand peak of iron ores (crude steel) will reach around 2015, 2016 for potassium salt, 2020 for refined lead, 2021 for bauxite (primary aluminum), 2022 for refined copper and 2023 for zinc. China's demand for iron ores (crude steel), bauxite (primary aluminum) and zinc in the future 20 years will decline among the world's demand, while that for refined copper, refined lead and potassium salt will slightly increase. The demand for bulk mineral products still remains high. In 2015-2035, China's accumulative demand for iron ores (crude steel) will be 20.313 Gt (13.429 Gt), 0.304 Gt for refined copper, 2.466 Gt (0.616 Gt) of bauxite (primary aluminum), 0.102 Gt of refined lead, 0.138 Gt of zinc and 0.157 Gt of potassium salt, and they account for the world's YOY (YOY) accumulative demand of 35.17%, 51.09%, 48.47%, 46.62%, 43.95% and 21.84%, respectively. This proportion is 49.40%, 102.52%, 87.44%, 105.65%, 93.62% and 106.49% of that in 2014, respectively. From the supply side of China's bulk mineral resources, it is forecasted that the accumulative supply of primary (mine) mineral products in 2015-2035 is 4.046 Gt of iron ores, 0.591 Gt of copper, 1.129 Gt of bauxite, 63.661 Mt of (mine) lead, 0.109 Gt of (mine) zinc and 0.128 Gt of potassium salt, which accounts for 8.82%, 13.92%, 26.67%, 47.09%, 33.04% and 15.56% of the world's predicted YOY production, respectively. With the rapid increase in the smelting capacity of iron and steel and alumina, the rate of capacity utilization for crude steel, refined copper, alumina, primary aluminum and refined lead in 2014 was 72.13%, 83.63%, 74.45%, 70.76% and 72.22%, respectively. During 2000-2014, the rate of capacity utilization for China's crude steel and refined copper showed a generally fluctuating decrease, which leads to an insufficient supply of primary mineral products. It is forecasted that the supply insufficiency of iron ores in 2015-2035 is 17.44 Gt, 0.245 Gt of copper in copper concentrates, 1.337 Gt of bauxite, 38.44 Mt of lead in lead concentrates and 29.19 Mt of zinc in zinc concentrates. China has gradually raised the utilization of recycled metals, which has mitigated the insufficient supply of primary metal products to some extent. It is forecasted that in 2015-2035 the accumulative utilization amount of steel scrap (iron ores) is 3.27 Gt (5.08 Gt), 70.312 Mt of recycled copper, 0.2 Gt of recycled aluminum, 48 Mt of recycled lead and 7.7 Mt of recycled zinc. The analysis on the supply and demand situation of China's bulk mineral resources in 2015-2035 suggests that the supply-demand contradiction for these six types of mineral products will decrease, indicative of a generally declining external dependency. If the use of recycled metal amount is counted in, the external dependency of China's iron, copper, bauxite, lead, zinc and potassium salt will be 79%, 65%, 26%, 8%, 16% and 18% in 2014, respectively. It is predicted that this external dependency will decrease to 62%, 64%, 20%, -0.93%, 16% and 14% in 2020, respectively, showing an overall decreasing trend. We propose the following suggestions correspondingly. (1) The demand peak of China's crude steel and potassium salt will reach during 2015-2023 in succession. Mining transformation should be planned and deployed in advance to deal with the arrival of this demand peak. (2) The supply-demand contradiction of China's bulk mineral resources will mitigate in the future 20 years, and the external dependency will decrease accordingly. It is suggested to adjust the mineral resources management policies according to different minerals and regions, and regulate the exploration and development activities. (3) China should further establish and improve the forced mechanism of resolving the smelting overcapacity of steel, refined copper, primary aluminum, lead and zinc to really achieve the goal of "reducing excess production capacity". (4) In accordance with the national strategic deployment of "One Belt One Road", China should encourage the excess capacity of steel, copper, alumina and primary aluminum enterprises to transfer to those countries or areas with abundant resources, high energy matching degree and relatively excellent infrastructure. Based on the national conditions, mining condition and geopolitics of the resources countries, we will gradually build steel, copper, aluminum and lead-zinc smelting bases, and potash processing and production bases, which will promote the excess capacity to transfer to the overseas orderly. (5) It is proposed to strengthen the planning and management of renewable resources recycling and to construct industrial base of renewable metal recycling. (6) China should promote the comprehensive development and utilization of paragenetic and associated mineral species to further improve the comprehensive utilization of bulk mineral resources.
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.
基金supported by the National Key Technology R&D Program of China (No. 2006BAH02A06)"333 Engineering"Project of Jiangsu Province
文摘Contract is a common and effective mechanism for supply chain coordination,which has been studied extensively in recent years.For a supply chain network model,contracts can be used to coordinate it because it is too ideal to obtain the network equilibrium state in practical market competition.In order to achieve equilibrium,we introduce revenue sharing contract into a supply chain network equilibrium model with random demand in this paper.Then,we investigate the influence on this network equilibrium state from demand disruptions caused by unexpected emergencies.When demand disruptions happen,the supply chain network equilibrium state will be broken and change to a new one,so the decision makers need to adjust the contract parameters to achieve the new coordinated state through bargaining.Finally,a numerical example with a sudden demand increase as a result of emergent event is provided for illustrative purposes.