This paper explores the dynamical feature of Hayward-Letelier black holes in AdS spacetime,emphasizing the effects of the Hayward parameter g,mass M,cosmological constant L,and modification parameterαon their geometr...This paper explores the dynamical feature of Hayward-Letelier black holes in AdS spacetime,emphasizing the effects of the Hayward parameter g,mass M,cosmological constant L,and modification parameterαon their geometry,thermodynamics,and observational features.By utilizing an effective potential method,we investigate the paths of particles,innermost stable circular orbit,and behavior of photon spheres,which connects them to the appearance of black hole shadows.Thermodynamic features such as Hawking temperature and entropy are studied for investigating the effect of L and thermal fluctuations on the stability of black holes.These discoveries connect theoretical ideas with observational astrophysics,which enhances our comprehension of ordinary black holes in AdS models.In this study,we analytically compute the greybody factor for a massless scalar field propagating in the vicinity of a black hole under the assumption of weak coupling to gravity.We investigate the behavior of the effective potential concerning the black hole's mass and charge,revealing that it reaches its maximum at lower values of the cloud of strings parameter.Our results indicate that the radial absorption rate of the scalar field exhibits significant fluctuations,which is influenced by the charge of the black hole and clouds of string,with implications for the dynamics of scalar fields in strong gravitational fields.展开更多
Hamiltonian structure of a rigid body in a circular orbit is established in this paper. With the reduction technique, the Hamiltonian structure of a rigid body in a circular orbit is derived from Lie-Poisson structure...Hamiltonian structure of a rigid body in a circular orbit is established in this paper. With the reduction technique, the Hamiltonian structure of a rigid body in a circular orbit is derived from Lie-Poisson structure of semidirect product, and Hamiltonian is derived from Jacobi's integral. The above method can be generalized to establish the Hamiltonian structure of a rigid body with a flexible attachment in a circular or- bit. At last, an example of stability analysis is given.展开更多
The cracking of coatings and the deformation of base frustrate the application of laser cladding technology especially on surface of the ring circular orbit.In order to solve the two problems above,the stress and stra...The cracking of coatings and the deformation of base frustrate the application of laser cladding technology especially on surface of the ring circular orbit.In order to solve the two problems above,the stress and strain fields of the laser cladding process on the ring circular orbit were analyzed through the finite-element method,based on the temperature field.The wedge module of the ring circular ring was the subject investigated. The calculating results show that during the cladding process the crank point tends to generate the transversal crack;the centre point on the coating/base interface tends to generate longitudinal crack;the intersecting edge of the coating and base tends to generate toe crack.Moreover,the cracking tendency of the outer marginal point is obviously greater than that of the inner marginal point.The rather high stress appears at the border position where the constraint exists,and the stress on the point in front of molten pool under the range of laser irradiation is large as well.And the displacement becomes larger as the cladding process proceeds.展开更多
In a recent article, we have corrected the traditional derivation of the Schwarzschild metric, thus obtaining the formulation of the correct Schwarzschild metric, which is different from the traditional Schwarzschild ...In a recent article, we have corrected the traditional derivation of the Schwarzschild metric, thus obtaining the formulation of the correct Schwarzschild metric, which is different from the traditional Schwarzschild metric. In this article, by starting from this correct Schwarzschild metric, we obtain the formulas of the correct gravitational potential and of the correct gravitational force in the case described by this metric. Moreover, we analyse these correct results and their consequences. Finally, we propose some possible crucial experiments between the commonly accepted theory and the same theory corrected according to this article.展开更多
The present paper deals with the study of equilibrium positions of the motion of a system of two artificial satellites connected by a light, flexible, inextensible and non-conducting cable under the influence of solar...The present paper deals with the study of equilibrium positions of the motion of a system of two artificial satellites connected by a light, flexible, inextensible and non-conducting cable under the influence of solar radiation pressure, earth’s oblateness, shadow of the earth and air resistance. Here, we study the case of circular orbit of the centre of mass of the system. We derive differential equations of motion of the system. General solutions of the differential equations are beyond the reach. On the other hand, the general solutions do not serve our purpose. Jacobian integral of the system has also been obtained. Thereafter equilibrium positions of the motion of the system have been obtained.展开更多
We investigate the photon sphere and marginally stable circular orbit of massive particles over the re-cently proposed regular black holes with sub-Planckian curvature and a Minkowskian core.We derive the effective po...We investigate the photon sphere and marginally stable circular orbit of massive particles over the re-cently proposed regular black holes with sub-Planckian curvature and a Minkowskian core.We derive the effective potential for geodesic orbits and determine the radius of circular photon orbits,with an analysis of the stability of these orbits.We extend our analysis to the background of a compact massive object(CMO)without a horizon,whose mass is below the lowest bound for the formation of a black hole.For massive particles,marginally stable cir-cular orbits become double-valued in the CMO phase.Through a comparison with Bardeen and Hayward black holes,we also find that the locations of the photon sphere and marginally stable circular orbit in the CMO phase with a Minkowskian core are evidently different from those in the CMO phase with a dS core,which potentially provides a way to distinguish between these two types of black holes by astronomical observation.Finally,we present the ob-servational constraint on the deviation parameter for such regular black holes using observed data from the black hole M87^(*).展开更多
基金Supported by the Ongoing Research Funding Program,(ORF-2025-650),King Saud University,Riyadh,Saudi Arabia.
文摘This paper explores the dynamical feature of Hayward-Letelier black holes in AdS spacetime,emphasizing the effects of the Hayward parameter g,mass M,cosmological constant L,and modification parameterαon their geometry,thermodynamics,and observational features.By utilizing an effective potential method,we investigate the paths of particles,innermost stable circular orbit,and behavior of photon spheres,which connects them to the appearance of black hole shadows.Thermodynamic features such as Hawking temperature and entropy are studied for investigating the effect of L and thermal fluctuations on the stability of black holes.These discoveries connect theoretical ideas with observational astrophysics,which enhances our comprehension of ordinary black holes in AdS models.In this study,we analytically compute the greybody factor for a massless scalar field propagating in the vicinity of a black hole under the assumption of weak coupling to gravity.We investigate the behavior of the effective potential concerning the black hole's mass and charge,revealing that it reaches its maximum at lower values of the cloud of strings parameter.Our results indicate that the radial absorption rate of the scalar field exhibits significant fluctuations,which is influenced by the charge of the black hole and clouds of string,with implications for the dynamics of scalar fields in strong gravitational fields.
基金The projeet supported by National Natural Science Foundation of China and Aeronautic Science Foundation.
文摘Hamiltonian structure of a rigid body in a circular orbit is established in this paper. With the reduction technique, the Hamiltonian structure of a rigid body in a circular orbit is derived from Lie-Poisson structure of semidirect product, and Hamiltonian is derived from Jacobi's integral. The above method can be generalized to establish the Hamiltonian structure of a rigid body with a flexible attachment in a circular or- bit. At last, an example of stability analysis is given.
文摘The cracking of coatings and the deformation of base frustrate the application of laser cladding technology especially on surface of the ring circular orbit.In order to solve the two problems above,the stress and strain fields of the laser cladding process on the ring circular orbit were analyzed through the finite-element method,based on the temperature field.The wedge module of the ring circular ring was the subject investigated. The calculating results show that during the cladding process the crank point tends to generate the transversal crack;the centre point on the coating/base interface tends to generate longitudinal crack;the intersecting edge of the coating and base tends to generate toe crack.Moreover,the cracking tendency of the outer marginal point is obviously greater than that of the inner marginal point.The rather high stress appears at the border position where the constraint exists,and the stress on the point in front of molten pool under the range of laser irradiation is large as well.And the displacement becomes larger as the cladding process proceeds.
文摘In a recent article, we have corrected the traditional derivation of the Schwarzschild metric, thus obtaining the formulation of the correct Schwarzschild metric, which is different from the traditional Schwarzschild metric. In this article, by starting from this correct Schwarzschild metric, we obtain the formulas of the correct gravitational potential and of the correct gravitational force in the case described by this metric. Moreover, we analyse these correct results and their consequences. Finally, we propose some possible crucial experiments between the commonly accepted theory and the same theory corrected according to this article.
文摘The present paper deals with the study of equilibrium positions of the motion of a system of two artificial satellites connected by a light, flexible, inextensible and non-conducting cable under the influence of solar radiation pressure, earth’s oblateness, shadow of the earth and air resistance. Here, we study the case of circular orbit of the centre of mass of the system. We derive differential equations of motion of the system. General solutions of the differential equations are beyond the reach. On the other hand, the general solutions do not serve our purpose. Jacobian integral of the system has also been obtained. Thereafter equilibrium positions of the motion of the system have been obtained.
基金Supported in part by the Natural Science Foundation of China(11875053,12035016)supported by the Beijing Natural Science Foundation(1222031)+1 种基金the Sichuan Youth Science and Technology Innovation Research Team with(21CXTD0038)Central Government Funds of Guiding Local Scientific and Technological Development for Sichuan Province with(2021ZYD0032)。
文摘We investigate the photon sphere and marginally stable circular orbit of massive particles over the re-cently proposed regular black holes with sub-Planckian curvature and a Minkowskian core.We derive the effective potential for geodesic orbits and determine the radius of circular photon orbits,with an analysis of the stability of these orbits.We extend our analysis to the background of a compact massive object(CMO)without a horizon,whose mass is below the lowest bound for the formation of a black hole.For massive particles,marginally stable cir-cular orbits become double-valued in the CMO phase.Through a comparison with Bardeen and Hayward black holes,we also find that the locations of the photon sphere and marginally stable circular orbit in the CMO phase with a Minkowskian core are evidently different from those in the CMO phase with a dS core,which potentially provides a way to distinguish between these two types of black holes by astronomical observation.Finally,we present the ob-servational constraint on the deviation parameter for such regular black holes using observed data from the black hole M87^(*).
