WoS İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8653
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Article General Formulation of the Scattered Matter Waves by a Quantum Shutter(Tubitak Scientific & Technological Research Council Turkey, 2009) Umul, Yusuf Z.The scattering process of matter waves by a quantum shutter is investigated by using the spectrum integral representation. The scattered fields are expressed in terms of the Fresnel function. It is shown that the obtained equation gives the Moshinsky function for a one dimensional problem of the plane wave. Also a general integral representation is derived for two dimensional problems. The scattering of matter waves for some special wave-packets are examined analytically and numerically.Article Citation - WoS: 6Citation - Scopus: 8General Formulation of the Scattered Matter Waves by a Quantum Shutter(2009) Umul, Z. Yusuf; Umul, Yusuf Z.The scattering process of matter waves by a quantum shutter is investigated by using the spectrum integral representation. The scattered fields are expressed in terms of the Fresnel function. It is shown that the obtained equation gives the Moshinsky function for a one dimensional problem of the plane wave. Also a general integral representation is derived for two dimensional problems. The scattering of matter waves for some special wave-packets are examined analytically and numerically.Article Comparison of Diffraction Methods for Lunar Occultations(Elsevier Gmbh, 2020) Umul, Yusuf Z.The only analytical method, which is used for the mathematical analysis of lunar occultations, is the Fresnel diffraction. The Fresnel integral is derived from the diffraction integral of Kirchhoff under some approximations. This paper aims to compare this method with the exact solution of Sommerfeld, which is obtained for a perfect electric conductor half-plane. The geometrical optics and diffracted fields are expressed separately. Numerical simulations are given for the comparison of two different total and diffracted waves.Article Citation - WoS: 7Citation - Scopus: 9Rubinowicz Transform of the Mtpo Surface Integrals(Elsevier Science Bv, 2008) Umul, Yusuf Z.The surface integral of the modified theory of physical optics is reduced to a line integral by using the Rubinowicz transform for the incident scattered fields by an arbitrary aperture in a black surface. The integral theorem of Kirchhoff is applied to the scattering geometry and the diffracted fields are expressed in terms of a line integral along the contour of the diffracting edge. (C) 2008 Elsevier B.V. All rights reserved.Article Citation - WoS: 4Uniform Asymptotic Theory for the Edge Diffraction of Cylindrical Waves(inst Engineering Technology-iet, 2017) Umul, Yusuf ZiyaThe uniform asymptotic theory of diffraction is reintroduced in terms of the Fresnel cylinder function for the diffraction problems of cylindrical waves. The transition function of the above theory, which compensates the discontinuities of the diffracted wave, is constructed according to the new function. The scattering problem of waves by a resistive half-plane is studied by the aid of the improved method. The uniform wave expressions are compared with the ones, obtained by the Fresnel integral at the near and far fields of the edge.Article Citation - WoS: 12Citation - Scopus: 13Three Dimensional Modified Theory of Physical Optics(Elsevier Gmbh, 2016) Umul, Yusuf ZiyaThe three dimensional version of the modified theory of physical optics is introduced with the aid of a Green's function that satisfies the Helmholtz equation in local spherical coordinates. The algorithm which leads to the construction of the scattering integral is given. The method is applied to the three dimensional diffraction problem of plane waves by a perfectly conducting half-plane. The comparison of the resulting field expressions with the literature shows that the modified theory of physical optics leads to the exact solution. (C) 2015 Elsevier GmbH. All rights reserved.Article Citation - WoS: 1Citation - Scopus: 1Interaction of Electromagnetic Waves With a Resistive Half-Plane(Springer France, 2016) Umul, Yusuf Z.The interaction process of electromagnetic waves by a resistive half-plane is investigated. The scattered geometrical optics fields are obtained by subtracting the incident field from the total geometrical optics waves. The physical optics integral of the scattered waves is derived with the aid of the scattered geometrical optics fields. The edge diffracted waves are derived from the physical optics integral by the edge point technique. A correction field is added to the diffracted fields in order to obtain a solution that satisfies the resistive boundary conditions on the surface of the half-screen. The uniform diffracted fields are expressed in terms of the Fresnel function and the resultant field representations are compared with the literature numerically.Article Citation - WoS: 11Citation - Scopus: 9Diffraction of Cylindrical Waves by a Perfectly Conducting Half-Screen: a Modified Theory of Physical Optics Solution(Wiley-blackwell, 2016) Umul, Yusuf Ziya; Ziya Umul, YusufThe scattering problem of waves, radiated by a line source, is investigated by the method of modified theory of physical optics. The solution is obtained for both of the Dirichlet and Neumann boundary conditions. Two dimensional modified theory of physical optics integral is considered, since the problem is symmetric according to one of the spatial coordinates. The scattering integral is directly evaluated and a new function is defined for the scattered fields. The mathematical properties of the function are studied. The total, geometrical optics and diffracted waves are analyzed numerically. (C) 2016 Wiley Periodicals, Inc. View this article online at wileyonlinelibrary.com.Article Citation - WoS: 15Citation - Scopus: 15Diffraction of Waves by a Resistive Half-Plane(Elsevier Science Bv, 2014) Umul, Yusuf Z.The scattered waves by a resistive half-plane are investigated with defining reflection and transmission coefficients for the diffracted waves. The coefficients are determined according to suitable conditions that are derived from the boundary conditions and the limiting cases of the reflection and transmission coefficients of the geometrical optics fields. The resultant field expressions are examined and compared with the literature numerically. (C) 2014 Elsevier By All rights reserved.Article Citation - WoS: 3Citation - Scopus: 4General Formulation of the Edge-Diffracted Paraxial Waves(Elsevier Sci Ltd, 2009) Umul, Yusuf Z.A general formula for edge-diffracted paraxial waves is derived in terms of the Fourier integral transform. It is observed that the scattered paraxial wave can be divided into components of the geometrical optics and diffracted fields in the spectral domain. An edge-diffracted Gaussian beam is examined numerically as an application of the formula. (C) 2008 Elsevier Ltd. All rights reserved.