Preface     

K. Kovári 《Rock Mechanics and Rock Engineering》1996,29(3):111-111

  相似文献   

Transversal ejection-collision orbits in Hill's problem forC≫1     

Joaquín Delgado Fernández 《Celestial Mechanics and Dynamical Astronomy》1988,44(3):299-307

In a recent paper [3], Lacomba and Llibre showed numerically the existence of two transversal ejection-collision orbits in Hill's problem for a valueC=5 of the Jacobian constant. This result can be used to prove the non-existence ofC ¹-extendable regular integrals for Hill's problem. Here we give an analytic proof of the existence of four ejection-collision orbits which are transversal for large enough values ofC.  相似文献   

X-ray,Hα, and radio observations of the two-ribbon flare of 16 May, 1981     

F. Fárník  J. Kaastra  B. Kálmán  M. Karlický  C. Slottje  B. Valniček 《Solar physics》1983,89(2):355-378

The paper is a contribution to the study of two-ribbon flares. A variety of observational material, i.e. Hα pictures, radio spectrum in the frequency band of 150–1000 MHz, radio map at 6 cm, fluxes at other frequencies, magnetograms and X-ray flux in a broad energy interval, enabled us to study the development of the 16 May, 1981 flare. The onset of the flare could be described by the model of Van Tend and Kuperus. A diminishing of the magnetic shear during the activation of the filament was observed. From radio and X-ray data it was found that pulsed acceleration took place in the region under the rising filament, the electrons propagating in a limited region both upwards to greater heights and downwards into the footpoints. Internal oscillations of the filament were observed. A manifestation of the primary process of interplanetary shock-wave generation was found. The 6 cm radio sources could be localized in the footpoints of magnetic loops.  相似文献   

Optimal sequencing for a multipurpose water supply system     

István Bogárdi  Ferenc Szidarovszky  Lucien Duckstein 《Advances in water resources》1978,1(5):275-284

The optimal sequencing of a multipurpose water supply system in the Hajduhátság region of Hungary is determined by dynamic programming. The goal function minimizes the present value of capital costs, operation costs, and economic losses due to water shortages. Future water requirements are considered to be random variables because of natural and forecasting uncertainties. The nonlinear optimization problem at each stage is equivalent to a readily solved game theoretical problem, the solution of which is straightforward. Sensitivity analysis performed with respect to economic losses, water requirements and discount rate, showed that optimal development and sequencing depend largely on the economic losses and the discount rate.  相似文献   

Light curves of the eclipsing systems of RS CVn-type     

María Lina Berríos-Salas  Margarita Guzmán-Vega  José Fernández-Labra  Manlio Maldini-Sánchez 《Astrophysics and Space Science》1989,162(2):205-209

This work presents the light curves for rotating spotted stars generated by a computational code developed by us. This code is based in a model of the system and its analytical solution. The work also present an analysis of the photometric curve variations with the changes in the model's parameters.As a first result we have simulated a temporal evolution of the light curve when the photospheric spot varies its size and position and we reproduced some observational light curves of the II Peg star.Work supported by Dirección de Investigación, Universidad de La Serena, Chile.  相似文献   

Radiative transfer for polarized light: Equivalence between Stokes parameters and coherency matrix formalisms     

J. Sánchez Almeida 《Solar physics》1992,137(1):1-14

Two formal solutions of the radiative transfer equation for polarized light have been proposed. One uses the Stokes parameters to describe the polarization, while the other uses the coherency matrix. It is shown in the present work that they are equivalent. Both can be used to compute response and contribution functions for the Stokes parameters and both require the solution of systems of differential equations with similar numbers of independent variables. New equations to solve the radiative transfer problem using the Stokes parameters formalism are presented. In addition, a computer code which synthesizes the Stokes profiles by means of these equations is described.The National Center for Atmospheric Research is sponsored by the National Science Foundation.  相似文献   

Mean surface brightness as a criterion for or against the expansion of the Universe     

Jaroslav Souček 《Astrophysics and Space Science》1988,141(1):103-131

Using the well-known relation for the mean surface brightness, the author gives the concept of the decision regarding the expansion of the Universe. The most serious obstacle on this way was the low precision of parameter measurements which one could achieve in the past. This paper brings the first step for eventual judgement if the Universe expand or not because the accuracy of measurements has advanced. In this sence, we need some more determinations with present accuracy to give the decisive result because the mean surface brightness must faint by 1.46 mag per square arc sec for red shift of 0.4, and this is sufficient to measure and statistically elaborate it.  相似文献   

The oscillating loop prominence of July 17, 1981     

B. Vršnak 《Solar physics》1984,94(2):289-297

Oscillatory motions of a loop prominence observed on July 17, 1981 are analysed. The oscillations were mainly horizontal, with a period of 8 min. Restoring force was a result of magnetic tension, and assuming a simplified magnetic field configuration the expression for frequencies of oscillations is derived and compared with the observations. Taking the observed period, the strength of the magnetic field permeating the prominence is estimated as 45 G. Finally, the stability of the prominence is discussed.  相似文献   

A generalization of Szebehely's equation for three dimensions     

Bálint Érdi 《Celestial Mechanics and Dynamical Astronomy》1982,28(1-2):209-218

Szebehely's equation for the potential generating a prescribed family of orbits in two dimensions is generalized for three-dimensional orbits. A simultaneous system of first-order linear partial differential equations is derived for the determination of the potential in the three-dimensional case. Solutions of this system are found in several cases including Kepler's problem too.Paper presented at the 1981 Oberwolfach Conference on Mathematical Methods in Celestial Mechanics.This paper is dedicated to Professor Victor Szebehely on the occasion of his 60th birthday.  相似文献   

The Earth-Moon tidal force function     

M. Burša 《Earth, Moon, and Planets》1983,28(1):49-53

The concept “the tidal force function of the Earth-Moon system” is introduced and its exact determination based on the Stokes constants (harmonic coefficients) in the external gravitational potential of both bodies is outlined. The exact determination of the torque due to the Moon exerted on the Earth may be performed in terms of the Stokes constants of both bodies and the mutual position of both ellipsoids of inertia.  相似文献