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141.
In this paper, we propose a fast primal-dual algorithm for solving bilaterally constrained total variation minimization problems which subsume the bilaterally constrained total variation image deblurring model and the two-phase piecewise constant Mumford-Shah image segmentation model. The presence of the bilateral constraints makes the optimality conditions of the primal-dual problem semi-smooth which can be solved by a semi-smooth Newton’s method superlinearly. But the linear system to solve at each iteration is very large and difficult to precondition. Using a primal-dual active-set strategy, we reduce the linear system to a much smaller and better structured one so that it can be solved efficiently by conjugate gradient with an approximate inverse preconditioner. Locally superlinear convergence results are derived for the proposed algorithm. Numerical experiments are also provided for both deblurring and segmentation problems. In particular, for the deblurring problem, we show that the addition of the bilateral constraints to the total variation model improves the quality of the solutions. 相似文献
142.
Tran Duc Thiep Truong Thi An Phan Viet Cuong Nguyen The Vinh Bui Minh Hue A. G. Belov O. D. Maslov G. V. Mishinsky V. I. Zhemenik 《Physics of Particles and Nuclei Letters》2017,14(1):102-111
We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements. 相似文献
143.
An approach for obtaining approximations of the Rayleigh wave velocity created by the principle of least squares is introduced. In view of this approach, Malischewsky's approximation of the Rayleigh wave velocity for Poisson ratios v in the set of [-1, 0.5] proposed quite recently is explained. It is shown that Malischewsky's approximation obtained by trial and error is (almost) identical with the one established by this approach. 相似文献
144.
Maike Andresen Dr. Isabelle Kleiner Prof. Dr. Martin Schwell Prof. Dr. Wolfgang Stahl Dr. Ha Vinh Lam Nguyen 《Chemphyschem》2019,20(16):2063-2073
Using two molecular jet Fourier transform spectrometers, the microwave spectrum of hexan-2-one, also called methyl n-butyl ketone, was recorded in the frequency range from 2 to 40 GHz. Three conformers were assigned and fine splittings caused by the internal rotations of the two terminal methyl groups were analyzed. For the acetyl methyl group CH3 COC3H6CH3, the torsional barrier is 186.9198(50) cm−1, 233.5913(97) cm−1, and 182.2481(25) cm−1 for the three observed conformers, respectively. The value of this parameter could be linked to the structure of the individual conformer, which enabled us to create a rule for predicting the barrier height of the acetyl methyl torsion in ketones. The very small splittings arising from the internal rotation of the butyl methyl group CH3COC3H6 CH3 could be resolved as well, yielding the respective torsional barriers of 979.99(88) cm−1, 1016.30(77) cm−1, and 961.9(32) cm−1. 相似文献
145.
Magnetization, specific heat, and electrical resistivity measurements have been performed on the superconductor Mo(3)Sb(7). Two kinds of transitions are observed at 2.3 and 50 K, respectively. The former is superconducting transition, while the latter is attributed to spin-gap formation. From the analysis of the experimental data, excitation gap, intra- and interdimer interactions are estimated as Delta/k(b) approximately 120 K, J(0)/k(B) approximately 150 K, and J(1)/k(B) approximately 55 K. The electronic structure calculations using the LSDA approximation show nesting property in the Fermi surface, favoring the superconductivity. 相似文献
146.
N. P. Vinh Tuong 《Rheologica Acta》1973,12(4):559-562
Sans résuméDocteur ès-science, maître de conférence, Laboratoire de Rhéologie I.S.M.C.M., 3, Rue Fernand Hainaut, F-93 Saint-Ouen (France).Avec 3 figures 相似文献
147.
The nucleon-alpha potential is calculated using a microscopic model with antisymmetrisation effects included from Brink and Boeker, Soper and Serber nucleon-nucleon interactions. The energy dependence of the potentials is also derived. 相似文献
148.
149.
Vinh Quang Nguyen 《Optics Communications》1985,55(5):335-336
A simple proof is presented of a theorem, which makes clear the general property of the effect of a resonance field on an arbitrarily degenerate two-level system. 相似文献
150.
The neutron spectrum and asymmetry have been calculated for 40Ca with different wave functions for the bound proton and the emitted neutron. The asymmetry is shown to be very sensitive to the behaviour of the wave functions near the nuclear surface while the spectrum is mostly sensitive to the strength of the real part of the neutron optical potential. 相似文献