The 1989 and following years were the periods in which many important economic and political tumovers took place in the world. That was the time when Berlin Wall fell down with scattering the Eastern block and many po...The 1989 and following years were the periods in which many important economic and political tumovers took place in the world. That was the time when Berlin Wall fell down with scattering the Eastern block and many politically independent states came into being, at the same time, ongoing about 70 years socialist system also started to change into liberal system. The constituted 27 states in 1991 were tended to liberal economic system instead of socialist economy, and these states were called as transition economies. In this study, the relationship between indebtedness and growth rate of transition countries were analyzed by panel autoregressive distributed lag model （ARDL）. Before panel ARDL application, stationary properties of the variables have been checked with first and second generation unit root test. For the second generation unit root tests, CADF tests have been used. Also cross section dependency has been examined by LM tests.展开更多
Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numeri...Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numerical method for calculating interior ballistics uses Lagrangian coordinates there the conservation of momentum and the energy balance are solved. A statement of the energy balance reflects the second law of thermodynamics. Lagrangian different grid and scheme for numerical calculation were used. Fully explicit scheme was employed. The solving includes two stability conditions： Courant and shock （artificial viscosity）. Numerical results were compared with the experimental research for pressure in the barrel in electro-thermal accelerator.展开更多
We investigate an electron transport bilayer fabricated at 〈110℃ to form all low-temperature processed, thermally stable, efficient perovskite solar cells with negligible hysteresis. The components of the bilayer cr...We investigate an electron transport bilayer fabricated at 〈110℃ to form all low-temperature processed, thermally stable, efficient perovskite solar cells with negligible hysteresis. The components of the bilayer create a symbiosis that results in improved devices compared with either of the components being used in isolation. A sol-gel derived ZnO layer facilitates improved energy level alignment and enhanced charge carrier extraction and a [6,6]-phenyl-C61-butyric acid methyl ester （PCBM） layer to reduce hysteresis and enhance perovskite thermal stability. The creation of a bilayer structure allows materials that are inherently unsuitable to be in contact with the perovskite active layer to be used in efficient devices through simple surface modification strategies.展开更多
In this paper, the theory of Quasi-steady is applied to the calculations of turbochargers matching tothe diesel engines and performance prediction. The engine performance prediction programs writtenin language C have ...In this paper, the theory of Quasi-steady is applied to the calculations of turbochargers matching tothe diesel engines and performance prediction. The engine performance prediction programs writtenin language C have been used for calculations of various turbocharged diesel engines. It has been confirmed by the comparisons with experimental data that the results of the calculation are reasonable,reliable and satisfied for the engineering applications.展开更多
In this paper, we investigate the impact of maturation delay on the positive equilibrium solutions in a stage-structured predator prey system. By analyzing the characteristic equation we derive the conditions for the ...In this paper, we investigate the impact of maturation delay on the positive equilibrium solutions in a stage-structured predator prey system. By analyzing the characteristic equation we derive the conditions for the emergence of Hopf bifurcation. By applying the normal form and the center manifold argument, the direction as well as the sta- bility of periodic solutions bifurcating from Hopf bifurcation is explored. Results show that maturation delay can change the nature of the positive equilibrium solutions, and the loss of equilibrium stability occurs as a consequence of Hopf bifurcation. When Hopf bifurcation takes place, periodic solution arises and is further demonstrated to be asymptotically stable. In addition, the periodic solutions appear only for intermediate maturation delay, that is, there exists a delay window, outside of which the positive equilibrium is locally stable. Furthermore, numerical analysis shows that Hopf bifur- cation is favored by a superior competition for adult predators to juveniles, a smaller mortality on juvenile and/or adult predators, and a higher resource carrying capacity. Interestingly, increasing food carrying capacity can lead to the emergence of irregular chaotic dynamics and regular limit cycles.展开更多
The combined effects of harvesting and time delay on predator-prey systems with Beddington-DeAngelis functional response are studied. The region of stability in model with harvesting of the predator, local stability o...The combined effects of harvesting and time delay on predator-prey systems with Beddington-DeAngelis functional response are studied. The region of stability in model with harvesting of the predator, local stability of equilibria and the existence of Hopf bifurcation are obtained by analyzing the associated characteristic equation due to the two-parameter geometric criteria developed by Ma, Feng and Lu [Discrete Contin. Dyn. Syst. Set B 9 （2008） 397-413]. The global stability of the positive equilibrium is inves- tigated by the comparison theorem. Furthermore, local stability of steady states and the existence of Hopf bifurcation for prey harvesting are also considered. Numerical simulations are given to illustrate our theoretical findings.展开更多
文摘The 1989 and following years were the periods in which many important economic and political tumovers took place in the world. That was the time when Berlin Wall fell down with scattering the Eastern block and many politically independent states came into being, at the same time, ongoing about 70 years socialist system also started to change into liberal system. The constituted 27 states in 1991 were tended to liberal economic system instead of socialist economy, and these states were called as transition economies. In this study, the relationship between indebtedness and growth rate of transition countries were analyzed by panel autoregressive distributed lag model （ARDL）. Before panel ARDL application, stationary properties of the variables have been checked with first and second generation unit root test. For the second generation unit root tests, CADF tests have been used. Also cross section dependency has been examined by LM tests.
文摘Electro-thermal accelerator uses high-voltage arc energy to heat the actuating medium, it being made from low-molecular weight material. Projectile acceleration is achieved by expansion of the actuating medium. Numerical method for calculating interior ballistics uses Lagrangian coordinates there the conservation of momentum and the energy balance are solved. A statement of the energy balance reflects the second law of thermodynamics. Lagrangian different grid and scheme for numerical calculation were used. Fully explicit scheme was employed. The solving includes two stability conditions： Courant and shock （artificial viscosity）. Numerical results were compared with the experimental research for pressure in the barrel in electro-thermal accelerator.
基金the China Scholarship Council for financial support for PhD studiessupport through the EPSRC Centre for Doctoral Training in Plastic Electronics(EP/L016702/1)
文摘We investigate an electron transport bilayer fabricated at 〈110℃ to form all low-temperature processed, thermally stable, efficient perovskite solar cells with negligible hysteresis. The components of the bilayer create a symbiosis that results in improved devices compared with either of the components being used in isolation. A sol-gel derived ZnO layer facilitates improved energy level alignment and enhanced charge carrier extraction and a [6,6]-phenyl-C61-butyric acid methyl ester （PCBM） layer to reduce hysteresis and enhance perovskite thermal stability. The creation of a bilayer structure allows materials that are inherently unsuitable to be in contact with the perovskite active layer to be used in efficient devices through simple surface modification strategies.
文摘In this paper, the theory of Quasi-steady is applied to the calculations of turbochargers matching tothe diesel engines and performance prediction. The engine performance prediction programs writtenin language C have been used for calculations of various turbocharged diesel engines. It has been confirmed by the comparisons with experimental data that the results of the calculation are reasonable,reliable and satisfied for the engineering applications.
文摘In this paper, we investigate the impact of maturation delay on the positive equilibrium solutions in a stage-structured predator prey system. By analyzing the characteristic equation we derive the conditions for the emergence of Hopf bifurcation. By applying the normal form and the center manifold argument, the direction as well as the sta- bility of periodic solutions bifurcating from Hopf bifurcation is explored. Results show that maturation delay can change the nature of the positive equilibrium solutions, and the loss of equilibrium stability occurs as a consequence of Hopf bifurcation. When Hopf bifurcation takes place, periodic solution arises and is further demonstrated to be asymptotically stable. In addition, the periodic solutions appear only for intermediate maturation delay, that is, there exists a delay window, outside of which the positive equilibrium is locally stable. Furthermore, numerical analysis shows that Hopf bifur- cation is favored by a superior competition for adult predators to juveniles, a smaller mortality on juvenile and/or adult predators, and a higher resource carrying capacity. Interestingly, increasing food carrying capacity can lead to the emergence of irregular chaotic dynamics and regular limit cycles.
文摘The combined effects of harvesting and time delay on predator-prey systems with Beddington-DeAngelis functional response are studied. The region of stability in model with harvesting of the predator, local stability of equilibria and the existence of Hopf bifurcation are obtained by analyzing the associated characteristic equation due to the two-parameter geometric criteria developed by Ma, Feng and Lu [Discrete Contin. Dyn. Syst. Set B 9 （2008） 397-413]. The global stability of the positive equilibrium is inves- tigated by the comparison theorem. Furthermore, local stability of steady states and the existence of Hopf bifurcation for prey harvesting are also considered. Numerical simulations are given to illustrate our theoretical findings.
