Hydrous phases play a fundamental role in the deep-water cycle on Earth. Understanding their stability and thermoelastic properties is essential for constraining their abundance using seismic tomography. However, dete...
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Hydrous phases play a fundamental role in the deep-water cycle on Earth. Understanding their stability and thermoelastic properties is essential for constraining their abundance using seismic tomography. However, determining their elastic properties at extreme conditions is notoriously challenging. The challenges stem from the complex behavior of hydrogen bonds under high pressures and temperatures (P,Ts). In this study, we evaluate how advanced molecular dynamics simulation techniques can address these challenges by investigating the adiabatic elasticity and acoustic velocities of δ−AlOOH, a critical and prototypical high-pressure hydrous phase. We compared the performances of three methods to assess their viability and accuracy. The thermoelastic tensor was computed up to 140 GPa and temperatures up to 2700 K using molecular dynamics with a DeePMD machine-learning interatomic potential based on the SCAN meta-GGA functional. The excellent agreement with ambient condition single-crystal ultrasound measurements and the correct description of velocity changes induced by H-bond disorder-symmetrization transition observed at 10 GPa in Brillouin scattering measurements underscores the accuracy and efficacy of our approach.
The authors are concerned with the sharp interface limit for an incompressible Navier-Stokes and Allen-Cahn coupled system in this *** the thickness of the diffuse interfacial zone,which is parameterized by ε,goes to...
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The authors are concerned with the sharp interface limit for an incompressible Navier-Stokes and Allen-Cahn coupled system in this *** the thickness of the diffuse interfacial zone,which is parameterized by ε,goes to zero,they prove that a solution of the incompressible Navier-Stokes and Allen-Cahn coupled system converges to a solution of a sharp interface model in the L^(∞)(L^(2))∩L^(2)(H^(1))sense on a uniform time interval independent of the small parameterε.The proof consists of two parts:One is the construction of a suitable approximate solution and another is the estimate of the error functions in Sobolev *** the careful energy estimates,a spectral estimate of the linearized operator for the incompressible Navier-Stokes and Allen-Cahn coupled system around the approximate solution is essentially used to derive the uniform estimates of the error *** convergence of the velocity is well expected due to the fact that the layer of the velocity across the diffuse interfacial zone is relatively weak.
Let γ(t) = (P1(t), . . ., Pn(t)) where Pi is a real polynomial with zero constant term for each 1 ≤ i ≤ n. We will show the existence of the configuration {x, x + γ(t)} in sets of positive density ǫ in [0, 1]n wit...
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This paper presents a second-order direct arbitrary Lagrangian Eulerian(ALE)method for compressible flow in two-dimensional cylindrical *** algorithm has half-face fluxes and a nodal velocity solver,which can ensure t...
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This paper presents a second-order direct arbitrary Lagrangian Eulerian(ALE)method for compressible flow in two-dimensional cylindrical *** algorithm has half-face fluxes and a nodal velocity solver,which can ensure the compatibility between edge fluxes and the nodal flow *** two-dimensional cylindrical geometry,the control volume scheme and the area-weighted scheme are used respectively,which are distinguished by the discretizations for the source term in the momentum *** two-dimensional second-order extensions of these schemes are constructed by employing the monotone upwind scheme of conservation law(MUSCL)on unstructured *** results are provided to assess the robustness and accuracy of these new schemes.
We report significant differences in high-pressure properties of vanadium at zero temperature and finite temperature when different projector augmented wave(PAW)potentials are used in simulations based on density func...
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We report significant differences in high-pressure properties of vanadium at zero temperature and finite temperature when different projector augmented wave(PAW)potentials are used in simulations based on density functional *** a PAW potential with only five electrons taken as valence electrons is used,the cold pressures in the high-pressure region are seriously underestimated,and an abnormality occurs in the melting curve of vanadium at about 400 *** show that the reason for these discrepancies lies in the differences in the descriptions of the interatomic force,electron dispersion,and anisotropy of electron bonding obtained from differentPAWpotentials at high pressure,which lead to striking differences in the mechanical stability of the *** propose a procedure for selecting PAW potentials suitable for simulations at high temperature and high *** results provide valuable guidance for future simulations of thermodynamic properties under extreme conditions.
Atmospheric thermal blooming (TB) effect is a critical nonlinear phenomenon affecting the transmission of high energy lasers. Adaptive optics (AO) technology partially reduces the impact of TB. However, phase compensa...
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Atmospheric thermal blooming (TB) effect is a critical nonlinear phenomenon affecting the transmission of high energy lasers. Adaptive optics (AO) technology partially reduces the impact of TB. However, phase compensation instability (PCI) is induced by correction errors, significantly constraining the effectiveness of AO. Based on the laser simulation software Easy-Laser, this paper explores the limits of ideal phase compensation, which ignores the correction errors of AO. The results demonstrate that ideal phase compensation improves correction compared to traditional AO. However, PCI still occurs, actually induced by the coupling of beam diffraction and the positive feedback of phase compensation. Based on this new understanding, we exploratorily apply mean filtering to TB correction and achieve satisfactory correction results. This demonstrates that removing high-frequency phase fluctuations is more effective in TB correction.
Stimulated Raman scattering(SRS)is one of the main instabilities affecting success of fusion ***,we study the relationship between Raman growth and Landau damping with various distribution functions combining the anal...
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Stimulated Raman scattering(SRS)is one of the main instabilities affecting success of fusion ***,we study the relationship between Raman growth and Landau damping with various distribution functions combining the analytic formulas and Vlasov *** Landau damping obtained by Vlasov-Poisson simulation and Raman growth rate obtained by Vlasov-Maxwell simulation are anti-correlated,which is consistent with our theoretical analysis *** distribution,flattened distribution,and bi-Maxwellian distribution are studied in detail,which represent three typical stages of *** also demonstrate the effects of plateau width,hot-electron fraction,hot-to-cold electron temperature ratio,and collisional damping on the Landau damping and growth *** gives us a deep understanding of SRS and possible ways to mitigate SRS through manipulating distribution functions to a high Landau damping regime.
We establish the global well-posedness for the multidimensional chemotaxis model with some classes of large initial data,especially the case when the rate of variation of ln v0(v0 is the chemical concentration)contain...
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We establish the global well-posedness for the multidimensional chemotaxis model with some classes of large initial data,especially the case when the rate of variation of ln v0(v0 is the chemical concentration)contains high oscillation and the initial density near the equilibrium is allowed to have large oscillation in ***,we show the optimal time-decay rates of the strong solutions under an additional perturbation assumption,which include specially the situations of d=2,3 and improve the previous time-decay *** method mainly relies on the introduce of the effective velocity and the application of the localization in Fourier spaces.
In this article, we consider the nonlinear Schrödinger equation on the cylinder Rd × T. In the long range case, we show there is no linear scattering state of the nonlinear Schrödinger equation on Rd &#...
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