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71.
Viorel Badescu 《Central European Journal of Physics》2010,8(3):463-479
The existence of life on a free-floating planet is conditioned by the existence of an optically thick atmosphere. This may
ensure the long-term thermal stability of a (liquid) solvent on the surface of that body. Requirements to be fulfilled by
a hypothetic gas constituent of a free-floating planet atmosphere are studied. The four gases analyzed here (nitrogen, carbon
dioxide, methane and ethane) are candidates. They may induce a higher opacity than molecular hydrogen, which has been considered
in previous research. The paper deals with preparation of tables of Rosseland mean opacity values. Selection of the ranges
of temperature and pressure is guided by life existence considerations. The range of temperatures involved (50 to 650 K) is
lower than usually found in the literature. The tables may be useful for studies related to free-floating planets, where the
usage of absorption opacity is a straightforward way to compute the energy flux in the atmosphere. Also, the results are useful
in all cases where radiation is transferred through dense layers of the gases considered in this paper. 相似文献
72.
In this paper we prove the internal feedback stabilization of steady-state solutions of semilinear parabolic equations and introduce a controller synthesis methodology based on finite element approximations of the original PDEs. Numerical tests are given for some one- and two-dimensional nonlinear parabolic equations. 相似文献
73.
In the present work we show that the local generalized monotonicity of a lower semicontinuous set-valued operator on some certain type of dense sets ensures the global generalized monotonicity of that operator. We achieve this goal gradually by showing at first that the lower semicontinuous set-valued functions of one real variable, which are locally generalized monotone on a dense subsets of their domain are globally generalized monotone. Then, these results are extended to the case of set-valued operators on arbitrary Banach spaces. We close this work with a section on the global generalized convexity of a real valued function, which is obtained out of its local counterpart on some dense sets. 相似文献
74.
Viorel Catană 《Integral Equations and Operator Theory》2010,66(1):41-52
We give a formula for the one-parameter strongly continuous semigroups ${e^{-tL^{\lambda}}}We give a formula for the one-parameter strongly continuous semigroups e-tLl{e^{-tL^{\lambda}}} and e-t [(A)\tilde]{e^{-t \tilde{A}}}, t > 0 generated by the generalized Hermite operator Ll, l ? R\{0}{L^{\lambda}, \lambda \in {\bf R}\backslash \{0\}} respectively by the generalized Landau operator ?. These formula are derived by means of pseudo-differential operators of the Weyl type, i.e. Weyl transforms, Fourier-Wigner
transforms and Wigner transforms of some orthonormal basis for L
2(R
2n
) which consist of the eigenfunctions of the generalized Hermite operator and of the generalized Landau operator. Applications
to an L
2 estimate for the solutions of initial value problems for the heat equations governed by L
λ respectively ?, in terms of L
p
norm, 1 ≤ p ≤ ∞ of the initial data are given. 相似文献
75.
Approximations to mild solutions of stochastic semilinear equations with non-Lipschitz coefficients 总被引:3,自引:0,他引:3
In the present paper, using a Picard Type method of approximation, we investigate the global existence of mild solutions for a class of Ito Type stochastic differential equations whose coefficients satisfy conditions more general than the Lipschitz and linear growth ones. 相似文献
76.
The paper studies the motion laws influence over the VIPAS1 industrial robot working. The motion differential equations, that govern the motion robot were established. Using them we can study the direct problem for the robot dynamics. There are the given motion laws for the accelerated and decreasing motion having triangular, trapezoidal and parabolic forms. The graphics of the forces and moments give us the possibility to make some recommandations under energetic aspects, for the optimal solutions about the VIPAS1 industrial robot. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
77.
Viorel Cîrcu Mihaela Ilie Monica Iliş Florea Dumitraşcu Ionela Neagoe Simona Păsculescu 《Polyhedron》2009,28(17):3739-3746
A series of cyclometallated 2-phenylpyridine Pt(II) complexes having N-benzoyl thiourea derivatives as ancillary ligands were prepared and characterised by elemental analysis, IR and UV–Vis spectroscopy, 1H and 13C NMR spectroscopy as well as by X-ray diffraction on single-crystal. All complexes were obtained as a single isomer with N atom of the 2-phenylpyridine ligand and S atom of the N-benzoyl thiourea derivatives coordinated in trans positions to the platinum metal as evidenced by using X-ray crystallography and NMR spectroscopy. All Pt(II) complexes show good luminescence properties at room temperature, both in dichloromethane solution and in solid state. 相似文献
78.
We prove the existence of a solution for the obstacle problem associated with the Kolmogorov operator corresponding to the stopping-time problem for stochastic Navier–Stokes equations in 2-D. 相似文献
79.
Viorel P. Paun 《Central European Journal of Physics》2009,7(2):264-269
The SEM microfractographies of Zircaloy-4 are studied by the time-series method. We first develop a computer application which
associates a time series to each SEM micrograph. Furthermore, we will apply the phase space embedding technique to reconstruct
the attractor and to compute the autocorrelation dimension. Using the fractal analysis technique, the SEM microfractographies
of the fracture surface of the Zircaloy-4 samples have been analyzed.
相似文献
80.