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Ground-state phase diagrams of ultrathin epitaxial alloy films are studied within the framework of a discrete lattice-model Hamiltonian incorporating competing elastic and chemical interactions. For bulk-immiscible alloy systems an infinite number of commensurate, long-period stripe-superstructure ground states are obtained as a function of chemical potential. The average periodicity of these stripe superstructures is found to be a nonmonotonic function of alloy composition, in contrast to the predictions of continuum theories for two-dimensional systems with competing interactions. 相似文献
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Malte Krack Sebastian TatzkoLars Panning-von Scheidt Jörg Wallaschek 《Journal of sound and vibration》2014
A novel probabilistic approach for the design of mechanical structures with friction interfaces is proposed. The objective function is defined as the probability that a specified performance measure of the forced vibration response is achieved subject to parameter uncertainties. The practicability of the approach regarding the extensive amount of required design evaluations is strictly related to the computational efficiency of the nonlinear dynamic analysis. Therefore, it is proposed to employ a recently developed parametric reduced order model (ROM) based on nonlinear modes of vibration, which can facilitate a decrease of the computational burden by several orders of magnitude. 相似文献
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M. Krack 《Theoretical chemistry accounts》2005,114(1-3):145-152
Pseudopotential parameter sets for the elements from H to Kr using the relativistic, norm-conserving, separable, dual-space
Gaussian-type pseudopotentials of Goedecker, Teter, and Hutter (GTH) are presented as optimized for the gradient-corrected
exchange-correlation functionals of Becke, Lee, Yang, and Parr (BLYP), Becke and Perdew (BP), and Perdew, Burke, and Ernzerhof
(PBE). The accuracy and reliability of the GTH pseudopotentials is shown by calculations for a series of small molecules.
Contribution to Karl Jug Honorary Issue 相似文献
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The salt-water interface is one of the most important and common on earth, playing a prominent role in disciplines such as atmospheric science and biology. Despite the apparent simplicity of such interfaces, arguably the most fundamental question of what the nature and structure of the liquid water/salt interface is under ambient conditions remains unclear. Here we address this issue with an ab initio molecular dynamics simulation of a nanoscale liquid water film on NaCl. A pronounced layering is observed in the film, with the density exhibiting a damped oscillatory behavior in the direction of the surface normal. In addition, water molecules in the contact layer are preferentially adsorbed at specific adsorption sites, involved in about 20% fewer hydrogen bonds with each other, and carry considerably reduced dipole moments compared to bulk liquid water. 相似文献
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A method for nonlinear modal analysis and synthesis: Application to harmonically forced and self-excited mechanical systems 总被引:2,自引:0,他引:2
The recently developed generalized Fourier–Galerkin method is complemented by a numerical continuation with respect to the kinetic energy, which extends the framework to the investigation of modal interactions resulting in folds of the nonlinear modes. In order to enhance the practicability regarding the investigation of complex large-scale systems, it is proposed to provide analytical gradients and exploit sparsity of the nonlinear part of the governing algebraic equations. 相似文献
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Buch V Mohamed F Krack M Sadlej J Devlin JP Parrinello M 《The Journal of chemical physics》2004,121(24):12135-12138
Acid solvation states are investigated in the recently discovered mixed ether:acid crystalline solids. The solids are simulated using on-the-fly molecular dynamics as implemented in the density functional code QUICKSTEP employing Gaussian basis sets. The solids are shown to display a remarkably broad range of acid solvation states, depending on the ether:acid ratio, including proton sharing in the 1:1 case, proton transfer to the ether in 1:2, and perturbed molecular acid in 1:6. The observed variation of the infrared spectra with the composition is accounted for qualitatively with the help of the calculations. 相似文献
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The parametrization of semiempirical molecular orbital methods is reviewed. The parametrization procedures are classified in three categories. The newly proposed category of consistency of parameters in a row of elements is applied in SINDO 1 to the Si atom. The calculations on test molecules and silicon clusters demonstrate that significant improvements in accuracy can be obtained in this way. © 1992 John Wiley & Sons, Inc. 相似文献