In this paper, the global existence of classical solution and global attractor for Camassa-Holm type equations with dissipative term are established by using fixed point theorem and a priori estimates.
In this paper, the global existence of classical solution and global attractor for Camassa-Holm type equations with dissipative term are established by using fixed point theorem and a priori estimates.
A double integral formula is derived for the distortion in an autoradiographic image due to electron ''cross-fire'', and a deconvolution procedure for image restoration using a fast Fourier transform a...
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A double integral formula is derived for the distortion in an autoradiographic image due to electron ''cross-fire'', and a deconvolution procedure for image restoration using a fast Fourier transform algorithm is developed. The technique is applied to a simulated autoradiograph of a uniform disc source and is found to give excellent results. Further image enhancement is obtained from the use of a spatially moving average smoothing process.
A theoretical study is made of the dependence of electron temperature, T e , on electron concentration, N e , and on solar activity F 10.7 flux in the daytime (10:00–14:00 L.T.) mid- to low-latitude F -layer. Continu...
A theoretical study is made of the dependence of electron temperature, T e , on electron concentration, N e , and on solar activity F 10.7 flux in the daytime (10:00–14:00 L.T.) mid- to low-latitude F -layer. Continuity, momentum and heat balance equations for the F -layer plasma are solved self-consistently. Different values of the solar activity F 10.7 flux give rise to different input model thermospheres; the solar ionizing flux and season are also varied. The consequent set of T e , N e , and F 10.7 values is analysed and compared to incoherent scatter and satellite observations of these variables. The observed quasi-linear dependence of T e on N e for N e values ≲ 5 × 10 5 cm −3 is simulated in the theoretical results and is due to the non-linear interaction of the several competing processes in the heat balance equation for the electron gas. For greater values of N , the quasi-linearity is less likely to occur: photoelectron heat input and electron-O + Coulomb heat loss tend to become dominant as N e increases.
The cooling of thermal electrons in the ionosphere by excitation of the fine structure energy levels of ground-state atomic oxygen is considered. From the evidence of theoretical studies of the fine structure transiti...
The cooling of thermal electrons in the ionosphere by excitation of the fine structure energy levels of ground-state atomic oxygen is considered. From the evidence of theoretical studies of the fine structure transition strengths and from modelling of plasma temperatures in the ionosphere, it is concluded that the fine structure cooling must be included for calculation of reliable values of electron temperature, particularly under sunspot minimum conditions. Debate continues on the precise value for the cooling rate. The rate depends on whether or not the energy levels are in thermodynamic equilibrium; ionospheric simulations of electron temperature are hampered by uncertainties in the heating rate and in other cooling rates.
Experimental observations and theoretical modelling of the terrestrial mid-latitude trough are reviewed. The mid-latitude trough is considered as an F -layer phenomenon, and its relationships to the lightion trough in...
Experimental observations and theoretical modelling of the terrestrial mid-latitude trough are reviewed. The mid-latitude trough is considered as an F -layer phenomenon, and its relationships to the lightion trough in the topside ionosphere and to the plasmapause are discussed. The observed morphology of the mid-latitude trough is summarised. Recent evidence on plasma temperatures in the trough is examined. The physical processes that may be important in the trough region are listed. Large-scale computational models that include some of those processes are described and the results compared with observations. Deficiencies in the models and possible future developments are mentioned.
The seasonal and solar activity variations of night-time total electron content (TEC) enhancements and their latitudinal and longitudinal dependencies in the northern equatorial anomaly region (11-23-degrees geomagnet...
The seasonal and solar activity variations of night-time total electron content (TEC) enhancements and their latitudinal and longitudinal dependencies in the northern equatorial anomaly region (11-23-degrees geomagnetic latitude) are studied by using data from three eastern longitude stations and one western longitude station. Two kinds of enhancement are observed: a postsunset enhancement which occurs most frequently in autumn and a postmidnight enhancement which occurs most frequently in summer. The enhancements, especially the postmidnight enhancements, are more frequent and stronger at the eastern longitude stations than at the western longitude station. The enhancements are weak and least frequent at 23-degrees geomagnetic latitude;the seasonal dependence of the postsunset enhancements at this latitude is different from that at lower latitudes confirming that the effect of the prereversal enhancement of the equatorial fountain, which produces the postsunset enhancements in TEC in the equatorial anomaly region, rarely reaches this latitude even under very high levels of solar activity.
作者：
Dong, S.Department of Mathematics
Center for Computational and Applied Mathematics Purdue University West Lafayette IN 47907 United States
Results of three-dimensional direct numerical simulations are presented for the Taylor-Couette system with counter-rotating cylinders at a radius ratio 0.89. The flow exhibits a pattern of banded alternating laminar a...
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In this paper we examine the numerical approximation of the limiting invariant measure associated with Feynman–Kac formulae. These are expressed in a discrete time formulation and are associated with a Markov chain a...
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作者：
Yunkai ZhouJames R.ChelikowskyXingyu GaoAihui ZhouDepartment of Mathematics
Southern Methodist UniversityDallasTX 75275USA Center for Computational Materials
Institute for Computational Engineering and Scienceand Departments of Physics and Chemical EngineeringUniversity of TexasAustinTX 78712USA HPCC
Institute of Applied Physics and Computational MathematicsBeijing100094China LSEC
Institute of Computational Mathematics and Scientific/Engineering ComputingAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China
The Teter,Payne,and Allan“preconditioning”function plays a significant role in planewave DFT *** function is often called the TPA *** present a detailed study of this“preconditioning”*** develop a general formula ...
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The Teter,Payne,and Allan“preconditioning”function plays a significant role in planewave DFT *** function is often called the TPA *** present a detailed study of this“preconditioning”*** develop a general formula that can readily generate a class of“preconditioning”*** functions have higher order approximation accuracy and fulfill the two essential“preconditioning”purposes as required in planewave DFT *** general class of functions are expected to have applications in other areas.
We study the multiscale finite element method for solving multiscale elliptic problems with highly oscillating coefficients,which is designed to accurately capture the large scale behaviors of the solution without res...
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We study the multiscale finite element method for solving multiscale elliptic problems with highly oscillating coefficients,which is designed to accurately capture the large scale behaviors of the solution without resolving the small scale *** key idea is to construct the multiscale base functions in the local partial differential equation with proper boundary *** boundary conditions are chosen to extract more accurate boundary information in the local *** consider periodic and non-periodic coefficients with linear and oscillatory boundary conditions for the base *** examples will be provided to demonstrate the effectiveness of the proposed multiscale finite element method.
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