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981.
D. Dangoisse J. Wascat J. M. Colmont 《International Journal of Infrared and Millimeter Waves》1981,2(6):1177-1191
A large number of emissions is obtained in the submillimeter and near millimeter range with the (H2CO)3 laser optically pumped by a CO2 laser. A study of the microwave absorption spectrum of the molecule carried out simultaneously with the submm analysis allows us to assign six of the laser lines in thev
5 excited state of the molecule and to determine the rotational constants and vibrational energy ofv
5. 相似文献
982.
S. Redner 《Journal of statistical physics》1981,25(1):15-23
We study the ground state properties of a one-dimensional Ising chain with a nearest-neighbor ferromagnetic interactionJ
1, and akth neighboranti-ferromagnetic interactionJ
k
. WhenJ
k/J1=–1/k, there exists a highly degenerate ground state with a residual entropy per spin. For the finite chain with free boundary conditions, we calculate the degeneracy of this state exactly, and find that it is proportional to the (N+k–1)th term in a generalized Fibonacci sequence defined by,F
N
(k)
=F
N–1
(k)
+F
N–k
(k)
. In addition, we show that this one-dimensional model is closely related to the following problems: (a) a fully frustrated two-dimensional Ising system with a periodic arrangement of nearest-neighbor ferro- and antiferromagnetic bonds, (b) close-packing of dimers on a ladder, a 2× strip of the square lattice, and (c) directed self-avoiding walks on finite lattice strips.Work partially supported by grants from AFOSR and ARO. 相似文献
983.
The properties of fluctuations in space in or outside thermal equilibrium are obtained by solving hierarchies of equations derived either from the Liouville or the Master equation. In particular we study the one-, two-, etc., time correlation functions that describe the spatial and temporal behavior of the fluctuations in space. Explicit solutions are obtained for a dilute gas. The Langevin approach is briefly discussed. Our results are compared with those obtained in the extensive literature, which is reviewed in some detail. 相似文献
984.
The extensivity property of entropy is clarified in the light of a critical examination of the entropy formula based on quantum
statistics and the relevant thermodynamic requirement. The modern form of the Gibbs paradox, related to the discontinuous
jump in entropy due to identity or non-identity of particles, is critically investigated. Qualitative framework of a new resolution
of this paradox, which analyses the general effect of distinction mark on the Hamiltonian of a system of identical particles,
is outlined. 相似文献
985.
N. G. van Kampen 《Journal of statistical physics》1981,25(3):431-442
In the presence of internal noise the variables describing a system are intrinsically stochastic. If they constitute a Markov process the expansion enables one to extract a deterministic macroscopic equation and to compute the fluctuations in successive approximations. In the lowest or linear noise approximation the fluctuations can be represented by a Langevin equation, provided it is handled appropriately. Higher orders cannot be described by any white noise Langevin equation. The question whether the equation has to be interpreted according to Itô or Stratonovich concerns these higher orders, for which the equation is not valid anyway. 相似文献
986.
The critical behavior of the layer magnetizations and local susceptibilities of theD-vector lattice models with Kac-type ferromagnetic interactions for a semi-infinite system is studied. These local quantities behave less singularly than the bulk ones, showing that this is not peculiar to the two-dimensional Ising model. Moreover, the limiting form (at the critical point) of the magnetization profile can be obtained, which, when properly scaled, satisfies the minimum condition in the Landau theory for a semi-infinite continuous system. Landau-type critical behavior is thus recovered. 相似文献
987.
U. G. Abdullaev 《Applied Mathematics Letters》1994,7(6):85-89
We consider the nonlinear parabolic equation ut = (k(u)ux)x + b(u)x, where u = u(x, t, x ε R1, t > 0; k(u) ≥ 0, b(u) ≥ 0 are continuous functions as u ≥ 0, b (0) = 0; k, b > 0 as u > 0. At t = 0 nonnegative, continuous and bounded initial value is prescribed. The boundary condition u(0, t) = Ψ(t) is supposed to be unbounded as t → +∞. In this paper, sufficient conditions for space localization of unbounded boundary perturbations are found. For instance, we show that nonlinear equation ut = (unux)x + (uβ)x, n ≥ 0, β >; n + 1, exhibits the phenomenon of “inner boundedness,” for arbitrary unbounded boundary perturbations. 相似文献
988.
Homotopy continuation methods can be applied to compute all finite solutions to a given polynomial system. Computations will be performed more efficiently if the symmetric structure of the system can be exploited. This paper presents the construction of a symmetric homotopy. Using this homotopy, only the paths according to the generating solutions have to be traced during continuation. 相似文献
989.
990.
P. M. Kort 《Journal of Optimization Theory and Applications》1994,83(3):489-509
The purpose of this paper is to determine the effects of different pollution standards on the firm's resource allocation decisions. To do so, a dynamic model of the firm is developed in which it is assumed that production causes pollution as an inevitable byproduct. Concerning its investment policy, we suppose that the firm can choose between investing in productive capital goods and investing in abatement efforts.It is shown that, in some cases, future abatement expenses have a negative impact on the present level of productive investment, even if the pollution standard is not binding at the moment. This implies a really dynamic optimal investment policy for the firm, which cannot be obtained within a comparative static analysis.This research has been made possible by a fellowship of the Royal Netherlands Academy of Arts and Sciences. Comments by Frank van der Duyn Schouten and Piet Verheyen (Tilburg University) and by Raymond Gradus (Dutch Ministry of Finance, The Hague) are gratefully acknowledged. 相似文献