This paper presents a Lagrangian cell-centered conservative gas dynamics scheme. The piecewise constant pressures of cells arising from the current time sub-cell densities and the current time isentropic speed of soun...
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This paper presents a Lagrangian cell-centered conservative gas dynamics scheme. The piecewise constant pressures of cells arising from the current time sub-cell densities and the current time isentropic speed of sound are introduced. Multipling the initial cell density by the initial sub-cell volumes obtains the sub-cell Lagrangian masses, and dividing the masses by the current time sub-cell volumes gets the current time sub- cell densities. By the current time piecewise constant pressures of cells, a scheme that conserves the momentum and total energy is constructed. The vertex velocities and the numerical fluxes through the cell interfaces are computed in a consistent manner due to an original solver located at the nodes. The numerical tests are presented, which are representative for compressible flows and demonstrate the robustness and accuracy of the Lagrangian cell-centered conservative scheme.
The hybridization between the localized 4f level(f) with conduction(c) electrons in γ-Ce upon cooling has been previously revealed in single crystalline thin films experimentally and theoretically, whereas its influe...
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The hybridization between the localized 4f level(f) with conduction(c) electrons in γ-Ce upon cooling has been previously revealed in single crystalline thin films experimentally and theoretically, whereas its influence on the γ → α phase transition was not explicitly verified, due to the fact that the phase transition happened in the bulk-layer, leaving the surface in the γ phase. Here in our work, we circumvent this issue by investigating the effect of alloying addition of La on Ce, by means of crystal structure, electronic transport and angle resolved photoemission spectroscopy measurements, together with a phenomenological periodic Anderson model and a modified Anderson impurity model. Our current researches indicate that the weakening of f–c hybridization is the major factor in the suppression of γ → α phase transition by La doping. The consistency of our results with the effects of other rare earth and actinide alloying additions on the γ → α phase transition of Ce is also discussed. Our work demonstrates the importance of the interaction between f and c electrons in understanding the unconventional phase transition in Ce, which is intuitive for further researches on other rare earth and actinide metals and alloys with similar phase transition behaviors.
A quasi-relativistic distorted-wave approximation is developed to investigate the direct electron-impact ionization processes, in which the configuration interactions are considered in the initial and final states of ...
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A quasi-relativistic distorted-wave approximation is developed to investigate the direct electron-impact ionization processes, in which the configuration interactions are considered in the initial and final states of target. As an example, the direct detailed-level electron-impact ionization cross sections for the ground and low excited states of Ar^6＋ （3s^2, 3p^2, 3s3d） are calculated in the energy range from 1.02 to 15Ith （ Ith the ionization threshold）. Comparison with the available data demonstrates that our results are reasonable. The effects of configuration interactions are discussed, and the validity of transformation principles by statistical weights between configuration-averaged and detailed-level electron-impact ionization cross sections is analysed.
Absorption of acoustic wave propagation in a large variety of lossy media is characterized by an empirical power law function of frequency, α0｜ω＋^Ⅳ. It has long been noted that the exponent y ranges from 0 to 2 f...
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Absorption of acoustic wave propagation in a large variety of lossy media is characterized by an empirical power law function of frequency, α0｜ω＋^Ⅳ. It has long been noted that the exponent y ranges from 0 to 2 for diverse media. Recently, the present author J. Acoust. Soc. Am. 115 （2004） 1424] developed a fractional Laplacian wave equation to accurately model the power law diss^aation, which can be further reduced to the fractional Laplacian diffusion equation. The latter is known underlying the Lévy stable distribution theory. Consequently, the parameters y is found to be the Lévy stability index, which is known to be bounded within 0 〈 y ≤2. This finding first provides a theoretical explanation of empirical observations y ∈ [0, 2]. Statistically, the frequencydependent absorption can thus be understood a Lévy stable process, where the parameter y describes the fractal nature of attenuative media.
The Casimir effect of the deformed cavity field at finite temperature is investigated by generalizing the thermo field dynamics formalism into q-deformed *** has been shown that the impact of q-deformation on the Casi...
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The Casimir effect of the deformed cavity field at finite temperature is investigated by generalizing the thermo field dynamics formalism into q-deformed *** has been shown that the impact of q-deformation on the Casimir force only manifests in the finite temperature case and the expression for the ideal pure vacuum remains unchanged,which just coincides with the suggestions of Man’ko et al.[***.A 176(1993)173]about the nature of q-oscillators as the nonlinear vibrations of electromagnetic field.
The influence of parameters such as the strength and frequency of a periodic driving force on the tunneling dynamics is investigated in a symmetric triple-well potential. It is shown that for some special values of th...
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The influence of parameters such as the strength and frequency of a periodic driving force on the tunneling dynamics is investigated in a symmetric triple-well potential. It is shown that for some special values of the parameters, tunneling could be enhanced considerably or suppressed completely. Quantum fluctuation during the tunneling is discussed as well and the numerical results are presented and analysed by virtue of Floquet formalism.
There exists an Ehresmann connection on the fibred constrained sub-manifold defined by Pfaffian differential constraints. It is proved that curvature of the connection is closely related to the d-delta commutation rel...
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There exists an Ehresmann connection on the fibred constrained sub-manifold defined by Pfaffian differential constraints. It is proved that curvature of the connection is closely related to the d-delta commutation relation in the classical nonholonomic mechanics. It is also proved that conditions of complete integrability for Pfaffian systems in Frobenius sense are equivalent to the three requirements upon the conditional variations in the classical calculus of variations: (1) the variations belong to the constrained manifold, (2) variational operators commute with differential operators, (3) variations satisfy the Chetaev's conditions. Thus this theory verifies the conjecture or experience of researchers of mechanics on the integrability conditions in terms of variation calculus.
Based on ab initio calculations,we utilize the mean-field potential approach with the quantum modification in conjunction with stress–strain relation to investigate the elastic anisotropies and sound velocities of hc...
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Based on ab initio calculations,we utilize the mean-field potential approach with the quantum modification in conjunction with stress–strain relation to investigate the elastic anisotropies and sound velocities of hcp and bcc Be under high-temperature(0–6000 K)and high-pressure(0–500 GPa)*** propose a general definition of anisotropy for elastic moduli and sound *** suggest that the elastic anisotropy of Be is more significantly influenced by pressure than by *** pressure-induced increase of c/a ratio makes the anisotropy of hcp Be significantly ***,the hcp Be still exhibits smaller anisotropy than bcc Be in terms of elastic moduli and sound *** suggest that measuring the anisotropy in shear sound velocity may be an approach to distinguishing the hcp–bcc phase transition under extreme conditions.
The boundary value problem for quasi-linear parabolic system is solved by the finite difference method with intrinsic parallelism The existence and uniqueness and convergence theorems of the discrete vector solu tions...
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The boundary value problem for quasi-linear parabolic system is solved by the finite difference method with intrinsic parallelism The existence and uniqueness and convergence theorems of the discrete vector solu tions of the nonlinear difference system with intrinsic parallelism are proved The limiting vector function is just the unique generalized solution of the original problem for the parabolic system
We calculated the vibrational free energies of the selected ordered compounds in the Ag-Cu system by using two kinds of methods: (1) calculating the phonon dispersion and density of states and the consequently vibrati...
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We calculated the vibrational free energies of the selected ordered compounds in the Ag-Cu system by using two kinds of methods: (1) calculating the phonon dispersion and density of states and the consequently vibrational free energies by using the method of ab initio inverted interatomic potentials and dynamic matrix;(2) the vibrational free energies determined by a Debye-Griineisen approximation. The Ag-Cu phase diagram is calculated by the cluster variation method. The results show that the solubility at Ag-rich end of the calculated phase diagram considering vibrational modes by using the first method is in better agreement with the experimental.
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