我们在[5]中考察了形如(?)(t)=f(x(?))的泛函微分方程,其中 f 是互助映射(依 Smith[9]).本文在对 f 的更一般的假定下继续上述研究,新的假定使得方程(?)(t)=f(x(?))生成所谓 K 型单调半流,它以 Smith[8]所考察的 K 型单调系统作为其特款...我们在[5]中考察了形如(?)(t)=f(x(?))的泛函微分方程,其中 f 是互助映射(依 Smith[9]).本文在对 f 的更一般的假定下继续上述研究,新的假定使得方程(?)(t)=f(x(?))生成所谓 K 型单调半流,它以 Smith[8]所考察的 K 型单调系统作为其特款,本文的主要结果(定理4)给出了方程的解具有某种全局渐近稳定性的充分条件.展开更多
We consider a one-dimensional continuous model of nutron star, described by a compressible thermoviscoelastic system with a non-monotone equation of state, due to the effective Skyrme nuclear interaction between parti...We consider a one-dimensional continuous model of nutron star, described by a compressible thermoviscoelastic system with a non-monotone equation of state, due to the effective Skyrme nuclear interaction between particles. We will prove that, despite a possible destabilizing influence of the pressure, which is non-monotone and not always positive, the presence of viscosity and a sufficient thermal dissipation describe the global existence of solutions in H^4 with a mixed free boundary problem for our model.展开更多
In this paper, we prove the existence in H＋^2, an incomplete metric subspace of H^2×H^2×H^2, of global solutions to the system for a one-dimensional non-monotone fluid in bounded domainΩ=（0,1）. The resul...In this paper, we prove the existence in H＋^2, an incomplete metric subspace of H^2×H^2×H^2, of global solutions to the system for a one-dimensional non-monotone fluid in bounded domainΩ=（0,1）. The results in this paper have improved those previously related results.展开更多
This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possi...This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possible because of additional shoot through state introduced in zero state of the conventional inverter pulse width modulation and provides desired output AC voltage. Small distributed generation （DG） system with alternate energy sources requires power conditioning units with low cost, high efficiency and tolerance to wide range of input voltage variation and has to perform various functions such as dc-ac conversion, system control and achieve power quality norms. To meet some of these requirements a two-loop control strategy for ac side control with grid current feedback with PI control and inner filter capacitor current feedback with proportional control and on dc side PID control for Z-source capacitor voltage regulation are employed, which gives good transient response also suppress load and source disturbances effectively. Theoretical analysis of proposed scheme is established and then simulation results are presented to validate proposed control strategy.展开更多
We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyze...We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyzed the relationship between the characteristic of FACs at the PSBL in magnetotail and the Kp index. The main results indicated the followings： 1） In the different geomagnetic activity levels, the relative occurrence of FACs in PSBL increased monotonically with geomagnetic activity. 2） The density of FACs in PSBL increased monotonically with Kp index. In the storm main phase, the density of FACs increased dramatically, the maximum FACs approximately equaled 19.05 nA m-2 while Kp equaled 5.3） The variation of FACs density in PSBL was consistent with the variation of the Kp index. However, when AE〈800 nT, FACs density in PSBL increased with increasing AE, and when AE〉800 nT, it decreased with increasing AE. Therefore, our results suggested that the FACs density in PSBL had a closer correlation with Kp index.展开更多
Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generat...Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generation Here, we demonstrate by molecular dynamics simulations that an excited vibrating carbon nanotube （CNT） cantilever can act as an efficient and simple nanopump. Water molecules inside the vibrating cantilever are driven by centrifugal forces and can undergo a continuous flow from the fixed to free ends of the CNT. Further extensive simulations show that the pumping function holds good not only for a single-file water chain in a narrow （6,6） CNT, but also for bulk-like water columns inside wider CNTs, and that the water flux increases monotonically with increasing diameter of the nanotube.展开更多
Let （M,g（t）） be a compact Riemannian manifold and the metric g（t） evolve by the Ricci flow. We derive the evolution equation for the eigenvalues of geometric operator --△φ＋ cR under the Ricci flow and the nor...Let （M,g（t）） be a compact Riemannian manifold and the metric g（t） evolve by the Ricci flow. We derive the evolution equation for the eigenvalues of geometric operator --△φ＋ cR under the Ricci flow and the normalized Ricci flow, where A, is the Witten-Laplacian operator, φ∈C∞（M）, and R is the scalar curvature with respect to the metric g（t）. As an application, we prove that the eigenvalues of the geometric operator are nondecreasing along the Ricci flow coupled to a heat equation for manifold M with some Ricci curvature 1 condition when c 〉1/4.展开更多
The authors give some constructive factorization theorems for pluriharmonic maps from a Kaehler manifold into the unitary group U(N) and obtain some optimal upper bounds of minimal uniton numbers.
In this paper, we introduce the notion of Hermitian pluriharmonic maps from Hermitian manifold into Kiihler manifold. Assuming the domain manifolds possess some special exhaustion functions and the vecotor field V = J...In this paper, we introduce the notion of Hermitian pluriharmonic maps from Hermitian manifold into Kiihler manifold. Assuming the domain manifolds possess some special exhaustion functions and the vecotor field V = JMδJM satisfies some decay conditions, we use stress-energy tensors to establish some monotonicity formulas of partial energies of Hermitian pluriharmonic maps. These monotonicity inequalities enable us to derive some holomorphicity for these Hermitian pluriharmonic maps.展开更多
Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine ...Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.展开更多
文摘我们在[5]中考察了形如(?)(t)=f(x(?))的泛函微分方程,其中 f 是互助映射(依 Smith[9]).本文在对 f 的更一般的假定下继续上述研究,新的假定使得方程(?)(t)=f(x(?))生成所谓 K 型单调半流,它以 Smith[8]所考察的 K 型单调系统作为其特款,本文的主要结果(定理4)给出了方程的解具有某种全局渐近稳定性的充分条件.
文摘We consider a one-dimensional continuous model of nutron star, described by a compressible thermoviscoelastic system with a non-monotone equation of state, due to the effective Skyrme nuclear interaction between particles. We will prove that, despite a possible destabilizing influence of the pressure, which is non-monotone and not always positive, the presence of viscosity and a sufficient thermal dissipation describe the global existence of solutions in H^4 with a mixed free boundary problem for our model.
文摘In this paper, we prove the existence in H＋^2, an incomplete metric subspace of H^2×H^2×H^2, of global solutions to the system for a one-dimensional non-monotone fluid in bounded domainΩ=（0,1）. The results in this paper have improved those previously related results.
文摘This paper presents a single-phase Z-source inverter as a power conditioning system for a single phase utility connected system. Z-source inverter is a single-stage topology that has buck-boost feature, which is possible because of additional shoot through state introduced in zero state of the conventional inverter pulse width modulation and provides desired output AC voltage. Small distributed generation （DG） system with alternate energy sources requires power conditioning units with low cost, high efficiency and tolerance to wide range of input voltage variation and has to perform various functions such as dc-ac conversion, system control and achieve power quality norms. To meet some of these requirements a two-loop control strategy for ac side control with grid current feedback with PI control and inner filter capacitor current feedback with proportional control and on dc side PID control for Z-source capacitor voltage regulation are employed, which gives good transient response also suppress load and source disturbances effectively. Theoretical analysis of proposed scheme is established and then simulation results are presented to validate proposed control strategy.
基金supported by the National Natural Science Foundation of China (Grant Nos. 40804031, 41074114, 40921063)the Specialized Research Fund for State Key Laboratories
文摘We have studied 172 field-aligned currents （FACs） cases observed by the ClusterlI satellites when they crossed the plasma sheet boundary layer （PSBL） in the magnetotail from July to October 2001. We mainly analyzed the relationship between the characteristic of FACs at the PSBL in magnetotail and the Kp index. The main results indicated the followings： 1） In the different geomagnetic activity levels, the relative occurrence of FACs in PSBL increased monotonically with geomagnetic activity. 2） The density of FACs in PSBL increased monotonically with Kp index. In the storm main phase, the density of FACs increased dramatically, the maximum FACs approximately equaled 19.05 nA m-2 while Kp equaled 5.3） The variation of FACs density in PSBL was consistent with the variation of the Kp index. However, when AE〈800 nT, FACs density in PSBL increased with increasing AE, and when AE〉800 nT, it decreased with increasing AE. Therefore, our results suggested that the FACs density in PSBL had a closer correlation with Kp index.
基金This work was supported by the 973 Program （No. 2007CB936204）, National and Jiangsu Province National Science Foundation （NSF） （Nos. 10732040, 10802037, 30970557, and BK2008042） of China, and Nanjing University of Aeronautics and Astronautics Funds （No. BCXJ08-02）. The authors thank Drs. Yitao Dai, Chun Tang, and Zhuhua Zhang for helpful discussions.
文摘Nanopumps conducting fluids directionally through nanopores and nanochannels have attracted considerable interest for their potential applications in nanofiltration, water purification, and hydroelectric power generation Here, we demonstrate by molecular dynamics simulations that an excited vibrating carbon nanotube （CNT） cantilever can act as an efficient and simple nanopump. Water molecules inside the vibrating cantilever are driven by centrifugal forces and can undergo a continuous flow from the fixed to free ends of the CNT. Further extensive simulations show that the pumping function holds good not only for a single-file water chain in a narrow （6,6） CNT, but also for bulk-like water columns inside wider CNTs, and that the water flux increases monotonically with increasing diameter of the nanotube.
基金supported by National Natural Science Foundation of China(Grant Nos.11401514,11371310,11101352 and 11471145)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(Grant Nos.13KJB110029 and 14KJB110027)+2 种基金Foundation of Yangzhou University(Grant Nos.2013CXJ001 and 2013CXJ006)Fund of Jiangsu University of Technology(Grant No.KYY13005)Qing Lan Project
文摘Let （M,g（t）） be a compact Riemannian manifold and the metric g（t） evolve by the Ricci flow. We derive the evolution equation for the eigenvalues of geometric operator --△φ＋ cR under the Ricci flow and the normalized Ricci flow, where A, is the Witten-Laplacian operator, φ∈C∞（M）, and R is the scalar curvature with respect to the metric g（t）. As an application, we prove that the eigenvalues of the geometric operator are nondecreasing along the Ricci flow coupled to a heat equation for manifold M with some Ricci curvature 1 condition when c 〉1/4.
文摘The authors give some constructive factorization theorems for pluriharmonic maps from a Kaehler manifold into the unitary group U(N) and obtain some optimal upper bounds of minimal uniton numbers.
基金supported by National Natural Science Foundation of China(Grant Nos.11271071,11201400,10971029 and 11026062)Project of Henan Provincial Department of Education(Grant No.2011A110015)Talent Youth Teacher Fund of Xinyang Normal University
文摘In this paper, we introduce the notion of Hermitian pluriharmonic maps from Hermitian manifold into Kiihler manifold. Assuming the domain manifolds possess some special exhaustion functions and the vecotor field V = JMδJM satisfies some decay conditions, we use stress-energy tensors to establish some monotonicity formulas of partial energies of Hermitian pluriharmonic maps. These monotonicity inequalities enable us to derive some holomorphicity for these Hermitian pluriharmonic maps.
文摘Purpose： In Iran, the most common cause of injuries and the second leading cause of deaths are traffic accidents, and those problems impose a substantial financial burden on the society. This study aims to determine traffic accident mortality trends and their epidemiologic characteristics in the Kermanshah province, west of lran. Methods： In a cross sectional study, road traffic fatality data from 2004 to 2013 were analyzed to determine the epidemiological pattern of traffic accident mortality. Trend assessment was performed to ascertain the decreasing or increasing status. Chi-square and one-way analysis of variance （ANOVA） tests, as well as Poisson regression were used to determine the significance of the data in time. Data were analyzed using Excel and statistical package of SPSS version 19. Results： Out of 5110 people that died in traffic accidents, 4024 （78.7%） were males. The state of accidents indicated that 404 （43.8%） female pedestrians died as a result of car crashes, and 1330 （41.4%） males died because of car collisions. 1554 （31.9%） deaths happened to pedestrians and 1556 （32.1%） to vehicle drivers, and the rest belonged to vehicle passengers. Head trauma was the cause of death for as much as 3400 （69.9%） cases. Fatal crashes in which pedestrians were involved mostly occurred between the hours 13：00 to 15：00, while the time for vehicle drivers was between 16：00 to 18：00. 2882 people （59.1%） died before reaching to health care facilities. Traffic crash mortality trend for pedestrians follows a linear pattern with a gentle downward slope, but the trend shows various swings when it comes to vehicle drivers. Conclusion： The number of traffic crash deaths from 2004 to 2013 indicates a decreasing trend in two groups of road users： vehicle drivers and car occupants. This can be due to some interventions such as modification of traffic rules and enhancement of police control which has been implemented in recent years. Moreover, more attention should be paid to promote the optimal health care services to save the lives of the injured from traffic accidents.
