نتایج جستجو برای: WKB

تعداد نتایج: 1344  

A. Shidfar, Ali Zakeri,

This paper considers a linear one dimensional inverse heat conduction problem with non constant thermal diffusivity and two unknown terms in a heated bar with unit length. By using the WKB method, the heat flux at the end of boundary and initial temperature will be approximated, numerically. By choosing a suitable parameter in WKB method the ill-posedness of solution will be improved. Finally, ...

2004
K. Hagino

Using a method of local transmission matrix, we generalize the well-known WKB formula for a barrier penetrability to multi-channel systems. We compare the WKB penetrability with a solution of the coupled-channels equations, and show that the WKB formula works well at energies well below the lowest adiabatic barrier. We also discuss the eigen-channel approach to a multichannel tunneling, which m...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه علوم پایه دامغان 1389

در این پایان نامه به مدل سازی ریاضی و بررسی عمل تصویربرداری از پدیده تشدید مغناطیسی (mri)در رگ های خونی پرداخته شده است. ابتدا در فصل اول عملکرد دستگاه هایی که توسط آنها mri انجام می شود، بررسی شده اند. در فصل دوم مقدمات مربوط به بررسی ریاضی mri ارائه شده است. در فصل سوم به مدل سازی ریاضی پدیده تشدید مغناطیسی در رگ های خونی پرداخته شده است. ملاحظه می شود که در نهایت مدل ریاضی نتیجه شده به صورت ...

2008
Gro Hovhannisyan

We establish WKB estimates for 2 × 2 linear dynamic systems with a small parameter ε on a time scale unifying continuous and discrete WKB method. We introduce an adiabatic invariant for 2 × 2 dynamic system on a time scale, which is a generalization of adiabatic invariant of Lorentz’s pendulum. As an application we prove that the change of adiabatic invariant is vanishing as ε approaches zero. ...

1999
Marko Robnik Valery G. Romanovski

We investigate some properties of the WKB series for arbitrary analytic potentials and then specifically for potentials x (N even), where more explicit formulae for the WKB terms are derived. Our main new results are: (i) We find the explicit functional form for the general WKB terms σ k, where one has only to solve a general recursion relation for the rational coefficients. (ii) We give a syst...

2008
Chang Soo Park Soo-Young Lee

We investigate the effect of anharmonicity on the WKB approximation in a double well potential. By incorporating the anharmonic perturbation into the WKB energy splitting formula we show that the WKB approximation can be greatly improved in the region over which the tunneling is appreciable. We also observe that the usual WKB results can be obtained from our formalism as a limiting case in whic...

Journal: :J. Sci. Comput. 2009
Wei Wang Chi-Wang Shu

In this paper, we develop a multiscale local discontinuous Galerkin (LDG) method to simulate the one-dimensional stationary Schrödinger-Poisson problem. The stationary Schrödinger equation is discretized by the WKB local discontinuous Galerkin (WKB-LDG) method, and the Poisson potential equation is discretized by the minimal dissipation LDG (MD-LDG) method. The WKB-LDG method we propose provide...

Journal: :Archive for Rational Mechanics and Analysis 2016

Journal: :Journal of Functional Analysis 1999

1996
Marko Robnik Luca Salasnich

We calculate the WKB series for the angular momentum and the non–relativistic 3-dim Kepler problem. This is the first semiclassical treatment of the angular momentum for terms beyond the leading WKB approximation. We explain why the torus quantization (the leading WKB term) of the full problem is exact, even if the individual torus quantization of the angular momentum and of the radial Kepler p...

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