By performing density functional theory plus U calculations, we systematically study the structural, electronic, and magnetic properties of U02 under uniaxial tensile strain. The results show that the ideal tensile st...
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By performing density functional theory plus U calculations, we systematically study the structural, electronic, and magnetic properties of U02 under uniaxial tensile strain. The results show that the ideal tensile strengths along the [100], [110], and [111] directions are 93.6, 2Z7, and 16.4 GPa at strains of 0.44, 0.24, and 0.16, respectively. After electronic-structure investigation for tensile stain along the [001] direction, we find that the strong mixed ionic/covalent character of U-O bond is weakened by the tensile strain and there will occur an insulator to metal transition at strain over 0.30.
The reconstruction with minimized dispersion and controllable dissipation(MDCD) optimizes dispersion and dissipation separately and shows desirable properties of both dispersion and dissipation.A low dispersion finite...
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The reconstruction with minimized dispersion and controllable dissipation(MDCD) optimizes dispersion and dissipation separately and shows desirable properties of both dispersion and dissipation.A low dispersion finite volume scheme based on MDCD reconstruction is proposed which is capable of handling flow discontinuities and resolving a broad range of length *** the proposed scheme is formally second order accurate,the optimized dispersion and dissipation make it very accurate and robust so that the rich flow features encountered in practical engineering applications can be handled properly.A number of test cases are computed to verify the performances of the proposed scheme.
The 2D generalized stochastic Ginzburg-Landau equation with additive noise is considered. The compactness of the random dynamical system is established with a priori estimate method, showing that the random dynamical ...
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The 2D generalized stochastic Ginzburg-Landau equation with additive noise is considered. The compactness of the random dynamical system is established with a priori estimate method, showing that the random dynamical system possesses a random attractor in H^1 0.
This paper generalizes the single-shell Kidder＇s self-similar solution to the double-shell one with a discontinuity in density across the interface. An isentropic implosion model is constructed to study the Rayleigh-...
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This paper generalizes the single-shell Kidder＇s self-similar solution to the double-shell one with a discontinuity in density across the interface. An isentropic implosion model is constructed to study the Rayleigh-Taylor instability for the implosion compression. A Godunov-type method in the Lagrangian coordinates is used to compute the one-dimensional Euler equation with the initial and boundary conditions for the double-shell Kidder＇s self-similar solution in spherical geometry. Numerical results are obtained to validate the double-shell implosion model. By programming and using the linear perturbation codes, a linear stability analysis on the Rayleigh-Taylor instability for the double-shell isentropic implosion model is performed. It is found that, when the initial perturbation is concentrated much closer to the interface of the two shells, or when the spherical wave number becomes much smaller, the modal radius of the interface grows much faster, i.e., more unstable. In addition, from the spatial point of view for the compressibility effect on the perturbation evolution, the compressibility of the outer shell has a destabilization effect on the Rayleigh-Taylor instability, while the compressibility of the inner shell has a stabilization effect.
We perform a first-principles computational tensile test on PuO_(2)based on density-functional theory within a local density approximation(LDA)+U formalism to investigate its structural,mechanical,magnetic and intrins...
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We perform a first-principles computational tensile test on PuO_(2)based on density-functional theory within a local density approximation(LDA)+U formalism to investigate its structural,mechanical,magnetic and intrinsic bonding properties in four representative directions:[001],[100],[110]and[111].The stress-strain relations show that the ideal tensile strengths in the four directions are 81.2,80.5,28.3 and 16.8 GPa at strains of 0.36,0.36,0.22 and 0.18,***[001]and[100]directions are prominently stronger than the other two directions since more Pu-0 bonds participate in the pulling *** charge and density of state analysis along the[001]direction,we find that the strong mixed ioni%ovalent character of the Pu-0 bond is weakened by tensile strain and PuO_(2)will exhibit an insulator-to-metal transition after tensile stresses exceeding about 79 GPa.
Cryptosporidiosis is a zoonotic disease that affects humans and animals globally, posing a significant public health and veterinary concern. It is mainly transmitted through the faecal-oral route. To capture the inher...
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Cryptosporidiosis is a zoonotic disease that affects humans and animals globally, posing a significant public health and veterinary concern. It is mainly transmitted through the faecal-oral route. To capture the inherent variability in the dynamics of cryptosporidiosis, a continuous-time Markov chain (CTMC) stochastic model is developed and analysed, based on an analogous deterministic model. The aim is to investigate the probability of disease persistence in cattle, immunocompetent humans, and immunocompromised humans. The stochastic threshold in the CTMC stochastic model is computed using the multitype branching process. The probability of disease extinction, as determined through the multitype branching process, demonstrates a good match with the probability approximated through numerical simulations. Cryptosporidiosis is more likely to extinct if it emerges from infected immunocompetent human compartments than from infected immunocompromised human compartments. However, a major disease outbreak is probable if the disease originates from either infected cattle compartments or Cryptosporidium oocysts in the environment compartment. The finite time to cryptosporidiosis extinction is shorter when the disease is introduced by an infected human or cattle compared to exposed individuals. This suggests that the incubation period prolongs the extinction time. The results of the sensitivity analysis show that a 90% reduction in human shedding rates of Cryptosporidium oocysts into the environment carries the highest probability of disease extinction, provided that the disease originates from an infected human. Therefore, reducing the shedding rates of Cryptosporidium oocysts into the environment by infectious humans is critical for the control and prevention of cryptosporidiosis in susceptible populations. This underscores the importance of measures such as proper sanitation practices, environmental decontamination, and effective cattle farm management to eliminate Cryptos
In this paper, we establish the existence of the global weak solutions for the non-homogeneous incompressible magnetohydrodynamic equations with Navier boundary condi-tions for the velocity field and the magnetic fiel...
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In this paper, we establish the existence of the global weak solutions for the non-homogeneous incompressible magnetohydrodynamic equations with Navier boundary condi-tions for the velocity field and the magnetic field in a bounded domain Ω R^3. Furthermore,we prove that as the viscosity and resistivity coefficients go to zero simultaneously, these weaksolutions converge to the strong one of the ideal nonhomogeneous incompressible magneto-hydrodynamic equations in energy space.
The reproducing kernel particle method （RKPM） has been efficiently applied to problems with large deformations, high gradients and high modal density. In this paper, it is extended to solve a nonlocal problem modele...
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The reproducing kernel particle method （RKPM） has been efficiently applied to problems with large deformations, high gradients and high modal density. In this paper, it is extended to solve a nonlocal problem modeled by a fractional advectiondiffusion equation （FADE）, which exhibits a boundary layer with low regularity. We formulate this method on a moving least-square approach. Via the enrichment of fractional-order power functions to the traditional integer-order basis for RKPM, leading terms of the solution to the FADE can be exactly reproduced, which guarantees a good approximation to the boundary layer. Numerical tests are performed to verify the proposed approach.
We investigate the uniform regularity and zero kinematic viscosity-magnetic diffusion limit for the incompressible viscous magnetohydrodynamic equations with the Navier boundary conditions on the velocity and perfectl...
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We investigate the uniform regularity and zero kinematic viscosity-magnetic diffusion limit for the incompressible viscous magnetohydrodynamic equations with the Navier boundary conditions on the velocity and perfectly conducting conditions on the magnetic field in a smooth bounded domain Ω⊂R^(3).It is shown that there exists a unique strong solution to the incompressible viscous magnetohydrodynamic equations in a finite time interval which is independent of the viscosity coefficient and the magnetic diffusivity *** solution is uniformly bounded in a conormal Sobolev space and W^(1,∞)(Ω)which allows us to take the zero kinematic viscosity-magnetic diffusion ***,we also get the rates of convergence in L^(∞)(0,T;L^(2)),L^(∞)(0,T;W^(1,p))(2≤p<∞),and L^(∞)((0,T)×Ω)for some T>0.
A fully discrete finite difference scheme for dissipative Zakharov equations is analyzed. On the basis of a series of the time-uniform priori estimates of the difference solutions, the stability of the difference sche...
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A fully discrete finite difference scheme for dissipative Zakharov equations is analyzed. On the basis of a series of the time-uniform priori estimates of the difference solutions, the stability of the difference scheme and the error bounds of optimal order of the difference solutions are obtained in L^2 × H^1 × H^2 over a finite time interval （0, T]. Finally, the existence of a global attractor is proved for a discrete dynamical system associated with the fully discrete finite difference scheme.
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