The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatmen...The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatments were designed to analyze the absorption laws of N, P and K, and to discuss the effects of different N fertilizer application amounts on yield and yield composition factors of Chuanxiangyou 9838. The results showed that gross nutrient absorption in Chuanxiangyou 9838 was greatly varied at different developmental stages under rice-rape rotation with no-tillage. The maximum N absorption in Chuanxiangyou 9838 appeared at jointing stage followed by heading stage, thirdly the tillefing stage ; the P absorption in Chuanxiangyou 9838 presented the consecutively slight increase during seedling stage and mature stage ; the K absorption in Chuanxiangyou 9838 was mainly conducted from jointing stage to heading stage, during which K absorption accounts for 73.4% of the total absorption in whole developmental stage. Consequently, N fertilizer should be applied earlier ( before jointing stage), P fertilizer is suitable as base fertilizer and application of K fertilizer should be preferably conducted at early-middle period. When the yield reached 11 t/hm^2, the optimal N application amount in Chuanxiangyou 9838 was about 165 kg/hm^2.展开更多
The mean path length(MPL)of photons is a critical parameter to calculate tissue absorption coefficient as well as blood oxygenation using modified Beer-Lambert law,where in the differential path factor(DPF)is often as...The mean path length(MPL)of photons is a critical parameter to calculate tissue absorption coefficient as well as blood oxygenation using modified Beer-Lambert law,where in the differential path factor(DPF)is often assumed as constant over range of tissue absorption.By utilizing the Monte Carlo(MC)simulation of photon migrations in the leg,this study used four approaches to estimate MPL,and compared them with that determined by the MPL definition.The simulation results indicate that the DPF is remarkably affected by tissue absorption,at approximate 10% variation.A linear model is suggested to calculate MPL for measurements of tissue absorption as well as blood oxygenation using modified Beer-Lambert law.展开更多
AIM: To study the direct correlation between gastric dysrhythrnias and in vivo gastric muscle tone. METHODS: Five healthy dogs were implanted with 4 pairs of electrodes along the greater curvature, with a strain gau...AIM: To study the direct correlation between gastric dysrhythrnias and in vivo gastric muscle tone. METHODS: Five healthy dogs were implanted with 4 pairs of electrodes along the greater curvature, with a strain gauge (SG) being sutured parallel to the distal electrodes (2 cm above the pylorus). Intravenous vasopressin was given to induce gastric dysrhythrnia. The percentage of regular slow waves and SG energy were calculated. RESULTS: (1) the regularity of gastric rnyoelectric activity (GMA) was reduced during and after infusion of vasopressin; (2) SG energy was significantly decreased during the infusion of vasopressin; (3) the decrease in SG energy was well correlated with the reduction in GMA regularity; (4) SG energy was negatively correlated with bradygastria and tachygastria. CONCLUSION: Vasopressin inhibits gastric contractions and impairs gastric slow waves; gastric dysrhythrnias are associated with the reduced antral muscle contractions, and are indicative of antral hypornotility.展开更多
Tax procedures are factors that strongly affect the business environment. A simple and convenient tax procedures system will contribute to a good business environment by easing of tax returns preparation, reducing tax...Tax procedures are factors that strongly affect the business environment. A simple and convenient tax procedures system will contribute to a good business environment by easing of tax returns preparation, reducing tax compliance costs, and preventing corruption. This paper examines the results and impacts of previous tax procedures reform on Vietnam's business environment, identifies challenges of tax procedures reform now and the coming years, and discusses areas where further reforms are needed to sustain tax revenue and reduce compliance costs including: (1) wansparent and comprehensive guidance to all tax laws and other legal tax documents; (2) widening the application of risk management in tax administration; (3) continuing simplification of tax procedures; and (4) development of IT in tax administration.展开更多
Harmonization of tax policy at European level is the result of compromise that must be achieved between member states' sovereignty and obstacles that create differences in legal regime for different categories of tax...Harmonization of tax policy at European level is the result of compromise that must be achieved between member states' sovereignty and obstacles that create differences in legal regime for different categories of taxes. The current level of harmonization achieved by the member states clearly shows that the process of reconciliation of taxes will not be a spontaneous, nor will evolve rapidly. With the occasion of European Union [EU] enlargement in 2004 and 2007, disparities in income levels matter between nationals of member states have put more pressure on the cooperation between member states, but some progress has been made including in this area. The idea of harmonization of taxes in the European plan is not new. Context of pertinent and uniform EU position has occurred since the first treaties concluded between member states. The free movements of goods, persons, services and capital, without any obstruction became absolute values. Creating a European tax, set and charged uniformly to all and by all member states, would be possible only if the criteria of budgetary requirements, criteria of efficiency and equity criteria are taken into consideration. Ruling a uniform level of charging would lead to establishing a single tax, mission almost impossible as long as the legal framework on taxation and civil duties remains under the responsibility of each member of EU. This analysis seems to greatly restrict the area of taxes that may meet all requirements listed. EU is still far from time to harmonize VAT (value added tax) levels perceived, but it is noted that the value added tax, income tax and tax on benefits eventually could meet the characteristics of a uniform European tax, achieving unanimous agreement among member states.展开更多
The tax accounting and financial accounting' s different target, different legal basis, different accounting principles as well as the different time of recognition between incomes and expenses will result in signifi...The tax accounting and financial accounting' s different target, different legal basis, different accounting principles as well as the different time of recognition between incomes and expenses will result in significant differences between accounting income and taxable income. We think that drawing on the experience of the United States and other countries to establish the specialized accounting theory and methods, the implementation of tax accounting and financial accounting separation is an inevitable requirement. Whether the financial accounting and tax accounting should be separated, of which the key lies in the degree of difference and coordinability between accounting income and taxable income. We believe that from our tax system, financial system and the history and current status of the development of accounting systems perspective, it do not exist realistic necessity of the separation between the tax accounting and the financial accounting.展开更多
AIM:To study the pharmacological profile and inhibition of smooth muscle contraction by YFa and its analogs in conjunction with their receptor selectivity. METHODS:The effects of YFa and its analogs (D-Ala2) YFa, Y (D...AIM:To study the pharmacological profile and inhibition of smooth muscle contraction by YFa and its analogs in conjunction with their receptor selectivity. METHODS:The effects of YFa and its analogs (D-Ala2) YFa, Y (D-Ala2) GFMKKKFMRF amide and Des-Phe-YGGFMKKKFMR amide in guinea pig ileum (GPI) and mouse vas deferens (MVD) motility were studied using an isolated tissue organ bath system, and morphine and DynA (1-13) served as controls. Acetylcholine was used for muscle stimulation. The observations were validated by specific antagonist pretreatment experiments using naloxonazine, naltrindole and norbinaltor-phimine norBNI. RESULTS:YFa did not demonstrate significant inhibition of GPI muscle contraction as compared with mor-phine (15% vs 62%, P = 0.0002), but moderate inhibition of MVD muscle contraction, indicating the role of κ opioid receptors in the contraction. A moderate inhibition of GPI muscles by (Des-Phe) YFa revealed the role of anti-opiate receptors in the smooth muscle contraction. (D-Ala-2) YFa showed significant inhibition of smooth muscle contraction, indicating the involvement of mainly δ receptors in MVD contraction. These results were supported by specific antagonist pretreatment assays. CONCLUSION:YFa revealed its side-effect-free analgesic properties with regard to arrest of gastroin-testinal transit. The study provides evidences for the involvement of κ and anti-opioid receptors in smooth muscle contraction.展开更多
The absorption-compression heat pump (ACHP) has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the AC...The absorption-compression heat pump (ACHP) has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the ACHP with NH3/H20 as working fluid were performed. Thermodynamic properties of each point and heat transfer rate of each component in the cycle under basic operation conditions were calculated from the first law analysis. Following the second law of thermodynamics, the entropy generation of each component and the total entropy generation of the system were obtained. The effect~ of the heating temperature, heat source temperature, and compression ratio on the coefficient of performance (COP) and the total entropy generation ( STot ) of the system were examined. The results show that the increase in COP corresponds to a decrease in STot, and vice versa; besides, for certain operating conditions, an optimum compression ratio in the NH~/H20 ACHP exists.展开更多
Welfare and green growth rest heavily on an appropriate supply of safe water, the provision of adequate sewerage, and on energy services. These services are interdependent, as water is an integral part of electric-pow...Welfare and green growth rest heavily on an appropriate supply of safe water, the provision of adequate sewerage, and on energy services. These services are interdependent, as water is an integral part of electric-power generation; it is used directly in hydroelectric generation, and it is used extensively for cooling and emissions scrubbing in thermoelectric generation. Energy is also an integrated part of water services, as satisfying water needs for supply, purification, distribution, and treatment of wastewater requires energy sources. Water and energy utilities are however regulated without a specific focus on the interdependency of the two sectors and the possibilities to ensure sustainable use of the resources and reduction of greenhouse gasses by a better coordination. The article explains the possibilities of sustainable consumption and production of energy in the water utilities. It highlights EU legal framework that makes coordination at national level possible, and it gives examples and concludes--on the obstacles for the water utilities' future as energy-smart utilities that exist at the national level in Denmark.展开更多
In this paper, a classical system of ordinary differential equations is built to describe a kind of n-dimensional quantum systems. The absorption spectrum and the density of the states for the system are defined from ...In this paper, a classical system of ordinary differential equations is built to describe a kind of n-dimensional quantum systems. The absorption spectrum and the density of the states for the system are defined from the points of quantum view and classical view. From the Birkhoffian form of the equations, a Birkhoffian symplectic scheme is derived for solving n-dimensional equations by using the generating function method. Besides the Birkhoffian structure- preserving, the new scheme is proven to preserve the discrete local energy conservation law of the system with zero vector f . Some numerical experiments for a 3-dimensional example show that the new scheme can simulate the general Birkhoffian system better than the implicit midpoint scheme, which is well known to be symplectic scheme for Hamiltonian system.展开更多
The golden period of the development of China's overseas trades is most significant in the Song Dynasty, which established the legal mechanisms of the overseas trades with the perfect systems. These legal regulations...The golden period of the development of China's overseas trades is most significant in the Song Dynasty, which established the legal mechanisms of the overseas trades with the perfect systems. These legal regulations made clear the subjects of the overseas trade to a large extent, stipulated the procedures for the overseas trade, and at the same time, established the related legal liabilities and regulation means and methods of the governments. Although it met the huge demands of the development of the foreign trade, and had brought the economic income for the governments, yet because the governments had adopted the strict control measures, to a certain extent, it also restricted the rapid development of the foreign trade. This paper starts from the analysis of the legal subjects of the overseas trade in the Song Dynasty, and conducted the specific analysis of the trade procedures and other related contents of the legal systems of the overseas trade in the Song Dynasty.展开更多
Many researchers have studied single and double effect absorption cycles based on first and second lows of thermodynamics But so far the relation of different parameters inside these cycles to the second law of thermo...Many researchers have studied single and double effect absorption cycles based on first and second lows of thermodynamics But so far the relation of different parameters inside these cycles to the second law of thermodynamics in boiler and cooling tower has not been investigated. In this paper, a system comprised of a series flow double effect water-Lithium bromide absorption chiller, a boiler and a cooling tower is studied based on the first and second laws of thermodynamics, and also exergy analysis is investigated. For this purpose, mass and energy conservation laws governing the system are written, and coefficient of performance of the system, exergy destruction (loss) of each component and exergy efficiency have been calculated.展开更多
Plant photosynthesis is the fundamental driver of all the biospheric functions. Alpine meadow on the Tibetan Plateau is sensitive to rapid climate change, and thus can be considered an indicator for the response of te...Plant photosynthesis is the fundamental driver of all the biospheric functions. Alpine meadow on the Tibetan Plateau is sensitive to rapid climate change, and thus can be considered an indicator for the response of terrestrial ecosystems to climate change. However, seasonal variations in photosynthetic parameters, including the fraction of photosynthetically active radiation by canopy(FPAR), the light extinction coefficient(k) through canopy, and the leaf area index(LAI) of plant communities, are not known for alpine meadows on the Tibetan Plateau. In this study, we used field measurements of radiation components and canopy structure from 2009 to 2011 at a typical alpine meadow on the northern Tibetan Plateau to calculate these three photosynthetic parameters. We developed a satellite-based(NDVI and EVI) method derived from the Beer-Lambert law to estimate the seasonal dynamics of FPAR, k,and LAI, and we compared these estimates with the Moderate Resolution Imaging Spectroradiometer(MODIS) FPAR(FPAR_MOD) and LAI product(LAI_MOD). The results showed that the average daily FPAR was 0.33, 0.37 and 0.35, respectively, from 2009 to 2011, and that the temporal variations could be explained by all four satellite-based FPAR estimations, including FPAR_MOD, an FPAR estimation derived from the Beer-Lambert law with a constant k(FPAR_LAI), and two FPAR estimations from the nonlinear functions between the ground measurements of FPAR(FAPRg) and NDVI/EVI(FPAR_NDVI and FPAR_EVI). We found that FPAR_MOD seriously undervalued FPARg by over 40%. Tower-based FPAR_LAI also significantly underestimated FPARg by approximately 20% due to the constant k(0.5) throughout the whole growing seasons. This indicated that using FPAR_LAI to validate the FPAR_MOD was not an appropriate method in this alpine meadow because the seasonal variation of k ranged from 0.19 to 2.95 in this alpine meadow. Thus, if the seasonal variation of k was taken into consideration, both FPAR_NDVI and FPAR_EVI provided better descriptions, with negligible overestimates of less than 5% of FAPRg(RMSE=0.05), in FPARg estimations than FPAR_MOD and FPAR_LAI. Combining the satellite-based(NDVI and EVI) estimations of seasonal FPAR and k, LAI_NDVI and LAI_EVI derived from the Beer-Lambert law also provided better LAIg estimations than LAI_MOD(less than 30% of LAIg). Therefore, this study concluded that satellite-based models derived from the Beer-Lambert law were a simple and efficient method for estimating the seasonal dynamics of FPAR, k and LAI in this alpine meadow.展开更多
The authors achieve a general law of precise asymptotics for a new kind of complete moment convergence of i.i.d. random variables, which includes complete con- vergence as a special case. It can describe the relations...The authors achieve a general law of precise asymptotics for a new kind of complete moment convergence of i.i.d. random variables, which includes complete con- vergence as a special case. It can describe the relations among the boundary function, weighted function, convergence rate and limit value in studies of complete convergence. This extends and generalizes the corresponding results of Liu and Lin in 2006.展开更多
The authors study the asymptotic behaviour of solutions of the heat equation and a number of evolution equations using scaling techniques. It is proved that in the framework of bounded data stabilization need not occu...The authors study the asymptotic behaviour of solutions of the heat equation and a number of evolution equations using scaling techniques. It is proved that in the framework of bounded data stabilization need not occur and the general asymptotic behaviour is complex. This behaviour reflects for large times, even on compact sets, the complexity of the initial data at infinity.展开更多
This paper considers optimal feedback control for a general continuous time finite-dimensional deterministic system with finite horizon cost functional. A practically feasible algorithm to calculate the numerical solu...This paper considers optimal feedback control for a general continuous time finite-dimensional deterministic system with finite horizon cost functional. A practically feasible algorithm to calculate the numerical solution of the optimal feedback control by dynamic programming approach is developed. The highlights of this algorithm are: a) It is based on a convergent constructive algorithm for optimal feedback control law which was proposed by the authors before through an approximation for the viscosity solution of the time-space discretization scheme developed by dynamic programming method; b) The computation complexity is significantly reduced since only values of viscosity solution on some local cones around the optimal trajectory are calculated. Two numerical experiments are presented to illustrate the effectiveness and fastness of the algorithm.展开更多
基金Project of Scientific and Technical Supporting Programs (2006AD05B06)Key Technologies Research and Development Program of Sichuan Province during the 10th Five-year Plan During the 11th Five-year Plan(2006YZGG-28)the project from International Plant Nutrition Institute (IPNI)~~
文摘The aim of the study is to investigate the absorption laws of nitrogen, phosphorus, and potassium, and proper nitrogen application in Chuanxiangyou 9838 under no-tillage cultivation. Five nitrogen application treatments were designed to analyze the absorption laws of N, P and K, and to discuss the effects of different N fertilizer application amounts on yield and yield composition factors of Chuanxiangyou 9838. The results showed that gross nutrient absorption in Chuanxiangyou 9838 was greatly varied at different developmental stages under rice-rape rotation with no-tillage. The maximum N absorption in Chuanxiangyou 9838 appeared at jointing stage followed by heading stage, thirdly the tillefing stage ; the P absorption in Chuanxiangyou 9838 presented the consecutively slight increase during seedling stage and mature stage ; the K absorption in Chuanxiangyou 9838 was mainly conducted from jointing stage to heading stage, during which K absorption accounts for 73.4% of the total absorption in whole developmental stage. Consequently, N fertilizer should be applied earlier ( before jointing stage), P fertilizer is suitable as base fertilizer and application of K fertilizer should be preferably conducted at early-middle period. When the yield reached 11 t/hm^2, the optimal N application amount in Chuanxiangyou 9838 was about 165 kg/hm^2.
基金Research Funds from North University of China(No.130087)
文摘The mean path length(MPL)of photons is a critical parameter to calculate tissue absorption coefficient as well as blood oxygenation using modified Beer-Lambert law,where in the differential path factor(DPF)is often assumed as constant over range of tissue absorption.By utilizing the Monte Carlo(MC)simulation of photon migrations in the leg,this study used four approaches to estimate MPL,and compared them with that determined by the MPL definition.The simulation results indicate that the DPF is remarkably affected by tissue absorption,at approximate 10% variation.A linear model is suggested to calculate MPL for measurements of tissue absorption as well as blood oxygenation using modified Beer-Lambert law.
文摘AIM: To study the direct correlation between gastric dysrhythrnias and in vivo gastric muscle tone. METHODS: Five healthy dogs were implanted with 4 pairs of electrodes along the greater curvature, with a strain gauge (SG) being sutured parallel to the distal electrodes (2 cm above the pylorus). Intravenous vasopressin was given to induce gastric dysrhythrnia. The percentage of regular slow waves and SG energy were calculated. RESULTS: (1) the regularity of gastric rnyoelectric activity (GMA) was reduced during and after infusion of vasopressin; (2) SG energy was significantly decreased during the infusion of vasopressin; (3) the decrease in SG energy was well correlated with the reduction in GMA regularity; (4) SG energy was negatively correlated with bradygastria and tachygastria. CONCLUSION: Vasopressin inhibits gastric contractions and impairs gastric slow waves; gastric dysrhythrnias are associated with the reduced antral muscle contractions, and are indicative of antral hypornotility.
文摘Tax procedures are factors that strongly affect the business environment. A simple and convenient tax procedures system will contribute to a good business environment by easing of tax returns preparation, reducing tax compliance costs, and preventing corruption. This paper examines the results and impacts of previous tax procedures reform on Vietnam's business environment, identifies challenges of tax procedures reform now and the coming years, and discusses areas where further reforms are needed to sustain tax revenue and reduce compliance costs including: (1) wansparent and comprehensive guidance to all tax laws and other legal tax documents; (2) widening the application of risk management in tax administration; (3) continuing simplification of tax procedures; and (4) development of IT in tax administration.
文摘Harmonization of tax policy at European level is the result of compromise that must be achieved between member states' sovereignty and obstacles that create differences in legal regime for different categories of taxes. The current level of harmonization achieved by the member states clearly shows that the process of reconciliation of taxes will not be a spontaneous, nor will evolve rapidly. With the occasion of European Union [EU] enlargement in 2004 and 2007, disparities in income levels matter between nationals of member states have put more pressure on the cooperation between member states, but some progress has been made including in this area. The idea of harmonization of taxes in the European plan is not new. Context of pertinent and uniform EU position has occurred since the first treaties concluded between member states. The free movements of goods, persons, services and capital, without any obstruction became absolute values. Creating a European tax, set and charged uniformly to all and by all member states, would be possible only if the criteria of budgetary requirements, criteria of efficiency and equity criteria are taken into consideration. Ruling a uniform level of charging would lead to establishing a single tax, mission almost impossible as long as the legal framework on taxation and civil duties remains under the responsibility of each member of EU. This analysis seems to greatly restrict the area of taxes that may meet all requirements listed. EU is still far from time to harmonize VAT (value added tax) levels perceived, but it is noted that the value added tax, income tax and tax on benefits eventually could meet the characteristics of a uniform European tax, achieving unanimous agreement among member states.
文摘The tax accounting and financial accounting' s different target, different legal basis, different accounting principles as well as the different time of recognition between incomes and expenses will result in significant differences between accounting income and taxable income. We think that drawing on the experience of the United States and other countries to establish the specialized accounting theory and methods, the implementation of tax accounting and financial accounting separation is an inevitable requirement. Whether the financial accounting and tax accounting should be separated, of which the key lies in the degree of difference and coordinability between accounting income and taxable income. We believe that from our tax system, financial system and the history and current status of the development of accounting systems perspective, it do not exist realistic necessity of the separation between the tax accounting and the financial accounting.
基金Supported by Council of Scientific and Industrial Research,Delhi
文摘AIM:To study the pharmacological profile and inhibition of smooth muscle contraction by YFa and its analogs in conjunction with their receptor selectivity. METHODS:The effects of YFa and its analogs (D-Ala2) YFa, Y (D-Ala2) GFMKKKFMRF amide and Des-Phe-YGGFMKKKFMR amide in guinea pig ileum (GPI) and mouse vas deferens (MVD) motility were studied using an isolated tissue organ bath system, and morphine and DynA (1-13) served as controls. Acetylcholine was used for muscle stimulation. The observations were validated by specific antagonist pretreatment experiments using naloxonazine, naltrindole and norbinaltor-phimine norBNI. RESULTS:YFa did not demonstrate significant inhibition of GPI muscle contraction as compared with mor-phine (15% vs 62%, P = 0.0002), but moderate inhibition of MVD muscle contraction, indicating the role of κ opioid receptors in the contraction. A moderate inhibition of GPI muscles by (Des-Phe) YFa revealed the role of anti-opiate receptors in the smooth muscle contraction. (D-Ala-2) YFa showed significant inhibition of smooth muscle contraction, indicating the involvement of mainly δ receptors in MVD contraction. These results were supported by specific antagonist pretreatment assays. CONCLUSION:YFa revealed its side-effect-free analgesic properties with regard to arrest of gastroin-testinal transit. The study provides evidences for the involvement of κ and anti-opioid receptors in smooth muscle contraction.
基金National Key Technologies R&D Program of China(No. 2012BABZ︱2B01)National Natural Science Foundation of China(No. 51106161)Innovation Foundation of President of Guangzhou Institute of Energy Conversion,Chinese Academy of Sciences(No. 0907r7)
文摘The absorption-compression heat pump (ACHP) has been considered as an effective approach to recover and utilize low-grade heat sources. In the present study, the first and second law thermodynamic analyses of the ACHP with NH3/H20 as working fluid were performed. Thermodynamic properties of each point and heat transfer rate of each component in the cycle under basic operation conditions were calculated from the first law analysis. Following the second law of thermodynamics, the entropy generation of each component and the total entropy generation of the system were obtained. The effect~ of the heating temperature, heat source temperature, and compression ratio on the coefficient of performance (COP) and the total entropy generation ( STot ) of the system were examined. The results show that the increase in COP corresponds to a decrease in STot, and vice versa; besides, for certain operating conditions, an optimum compression ratio in the NH~/H20 ACHP exists.
文摘Welfare and green growth rest heavily on an appropriate supply of safe water, the provision of adequate sewerage, and on energy services. These services are interdependent, as water is an integral part of electric-power generation; it is used directly in hydroelectric generation, and it is used extensively for cooling and emissions scrubbing in thermoelectric generation. Energy is also an integrated part of water services, as satisfying water needs for supply, purification, distribution, and treatment of wastewater requires energy sources. Water and energy utilities are however regulated without a specific focus on the interdependency of the two sectors and the possibilities to ensure sustainable use of the resources and reduction of greenhouse gasses by a better coordination. The article explains the possibilities of sustainable consumption and production of energy in the water utilities. It highlights EU legal framework that makes coordination at national level possible, and it gives examples and concludes--on the obstacles for the water utilities' future as energy-smart utilities that exist at the national level in Denmark.
基金Supported by National Nature Science Foundation of China under Grant No. 10701081
文摘In this paper, a classical system of ordinary differential equations is built to describe a kind of n-dimensional quantum systems. The absorption spectrum and the density of the states for the system are defined from the points of quantum view and classical view. From the Birkhoffian form of the equations, a Birkhoffian symplectic scheme is derived for solving n-dimensional equations by using the generating function method. Besides the Birkhoffian structure- preserving, the new scheme is proven to preserve the discrete local energy conservation law of the system with zero vector f . Some numerical experiments for a 3-dimensional example show that the new scheme can simulate the general Birkhoffian system better than the implicit midpoint scheme, which is well known to be symplectic scheme for Hamiltonian system.
文摘The golden period of the development of China's overseas trades is most significant in the Song Dynasty, which established the legal mechanisms of the overseas trades with the perfect systems. These legal regulations made clear the subjects of the overseas trade to a large extent, stipulated the procedures for the overseas trade, and at the same time, established the related legal liabilities and regulation means and methods of the governments. Although it met the huge demands of the development of the foreign trade, and had brought the economic income for the governments, yet because the governments had adopted the strict control measures, to a certain extent, it also restricted the rapid development of the foreign trade. This paper starts from the analysis of the legal subjects of the overseas trade in the Song Dynasty, and conducted the specific analysis of the trade procedures and other related contents of the legal systems of the overseas trade in the Song Dynasty.
文摘Many researchers have studied single and double effect absorption cycles based on first and second lows of thermodynamics But so far the relation of different parameters inside these cycles to the second law of thermodynamics in boiler and cooling tower has not been investigated. In this paper, a system comprised of a series flow double effect water-Lithium bromide absorption chiller, a boiler and a cooling tower is studied based on the first and second laws of thermodynamics, and also exergy analysis is investigated. For this purpose, mass and energy conservation laws governing the system are written, and coefficient of performance of the system, exergy destruction (loss) of each component and exergy efficiency have been calculated.
基金The National Key Research and Development Program of China(2016YFC0502001)The National Natural Science Foundation of China(41807331)The West Light Foundation of the Chinese Academy of Sciences(2018)。
文摘Plant photosynthesis is the fundamental driver of all the biospheric functions. Alpine meadow on the Tibetan Plateau is sensitive to rapid climate change, and thus can be considered an indicator for the response of terrestrial ecosystems to climate change. However, seasonal variations in photosynthetic parameters, including the fraction of photosynthetically active radiation by canopy(FPAR), the light extinction coefficient(k) through canopy, and the leaf area index(LAI) of plant communities, are not known for alpine meadows on the Tibetan Plateau. In this study, we used field measurements of radiation components and canopy structure from 2009 to 2011 at a typical alpine meadow on the northern Tibetan Plateau to calculate these three photosynthetic parameters. We developed a satellite-based(NDVI and EVI) method derived from the Beer-Lambert law to estimate the seasonal dynamics of FPAR, k,and LAI, and we compared these estimates with the Moderate Resolution Imaging Spectroradiometer(MODIS) FPAR(FPAR_MOD) and LAI product(LAI_MOD). The results showed that the average daily FPAR was 0.33, 0.37 and 0.35, respectively, from 2009 to 2011, and that the temporal variations could be explained by all four satellite-based FPAR estimations, including FPAR_MOD, an FPAR estimation derived from the Beer-Lambert law with a constant k(FPAR_LAI), and two FPAR estimations from the nonlinear functions between the ground measurements of FPAR(FAPRg) and NDVI/EVI(FPAR_NDVI and FPAR_EVI). We found that FPAR_MOD seriously undervalued FPARg by over 40%. Tower-based FPAR_LAI also significantly underestimated FPARg by approximately 20% due to the constant k(0.5) throughout the whole growing seasons. This indicated that using FPAR_LAI to validate the FPAR_MOD was not an appropriate method in this alpine meadow because the seasonal variation of k ranged from 0.19 to 2.95 in this alpine meadow. Thus, if the seasonal variation of k was taken into consideration, both FPAR_NDVI and FPAR_EVI provided better descriptions, with negligible overestimates of less than 5% of FAPRg(RMSE=0.05), in FPARg estimations than FPAR_MOD and FPAR_LAI. Combining the satellite-based(NDVI and EVI) estimations of seasonal FPAR and k, LAI_NDVI and LAI_EVI derived from the Beer-Lambert law also provided better LAIg estimations than LAI_MOD(less than 30% of LAIg). Therefore, this study concluded that satellite-based models derived from the Beer-Lambert law were a simple and efficient method for estimating the seasonal dynamics of FPAR, k and LAI in this alpine meadow.
基金supported by the National Natural Science Foundation of China(No.10571073)the 985 Program of Jilin University.
文摘The authors achieve a general law of precise asymptotics for a new kind of complete moment convergence of i.i.d. random variables, which includes complete con- vergence as a special case. It can describe the relations among the boundary function, weighted function, convergence rate and limit value in studies of complete convergence. This extends and generalizes the corresponding results of Liu and Lin in 2006.
文摘The authors study the asymptotic behaviour of solutions of the heat equation and a number of evolution equations using scaling techniques. It is proved that in the framework of bounded data stabilization need not occur and the general asymptotic behaviour is complex. This behaviour reflects for large times, even on compact sets, the complexity of the initial data at infinity.
文摘This paper considers optimal feedback control for a general continuous time finite-dimensional deterministic system with finite horizon cost functional. A practically feasible algorithm to calculate the numerical solution of the optimal feedback control by dynamic programming approach is developed. The highlights of this algorithm are: a) It is based on a convergent constructive algorithm for optimal feedback control law which was proposed by the authors before through an approximation for the viscosity solution of the time-space discretization scheme developed by dynamic programming method; b) The computation complexity is significantly reduced since only values of viscosity solution on some local cones around the optimal trajectory are calculated. Two numerical experiments are presented to illustrate the effectiveness and fastness of the algorithm.