Results 1 to 10 of about 45,671 (275)

A Method for Mounting Space Telescope Optical Systems Based on the Sensitivity Matrix of Intrinsic Coefficients [PDF]

Sensors
Aperture space telescopes are widely used in space debris size information detection and celestial body detection work. For the problem of limited space inside the optical system of large aperture telescopes, a space telescope mounting method based on ...
Han Hou, Hongchang Ding, Keyan Dong, Guohua Cao, Boyuan Wang   +4 more
doaj   +2 more sources

Non-classical periodic boundary value problems with impulsive conditions

Journal of New Results in Science, 2023
This study investigates some spectral properties of a new type of periodic Sturm-Liouville problem. The problem under consideration differs from the classical ones in that the differential equation is given on two disjoint segments that have a common end,
Sevda Nur Öztürk, Oktay Mukhtarov, Kadriye Aydemir   +2 more
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Method for determining eigen numbers in heat conduction problems for a cylinder

Известия высших учебных заведений: Проблемы энергетики, 2023
RELEVANCE. Due to the difficulties of finding eigenvalues and proper functions for bodies with axial (cylinder) and central (ball) symmetries defined in classical methods from the edge Sturm-Liouville problems, including Bessel equations whose exact ...
E. V. Kotova, R. M. Klebleev, V. A. Kudinov   +2 more
doaj   +1 more source

Variational characterizations for eigenfunctions of analytic self-adjoint operator functions [PDF]

Opuscula Mathematica, 2013
In this paper we consider Rellich's diagonalization theorem for analytic self-adjoint operator functions and investigate variational principles for their eigenfunctions and interlacing statements.
Georgios Katsouleas, John Maroulas
doaj   +1 more source

Solvability of Mixed Problems for a Fourth-Order Equation with Involution and Fractional Derivative

Fractal and Fractional, 2023
In the present work, two-dimensional mixed problems with the Caputo fractional order differential operator are studied using the Fourier method of separation of variables.
Mokhtar Kirane, Abdissalam A. Sarsenbi
doaj   +1 more source

Semi-classical calculations of energy levels and wave functions of hamiltonian systems with one and several degrees of freedom based on the method of classical and quantum normal forms

Физико-химические аспекты изучения кластеров, наноструктур и наноматериалов, 2023
The paper presents two schemes for the sequential construction of the classical normal form and its quantum analogue for some classes of classical Hamiltonian systems.
I.N. Belyaeva, N.I. Korsunov, N.A. Chekanov, A.N. Chekanov   +3 more
doaj   +1 more source

Multiple solutions of a Sturm-Liouville boundary value problem of nonlinear differential inclusion with nonlocal integral conditions

AIMS Mathematics, 2022
The existence of solutions for a Sturm-Liouville boundary value problem of a nonlinear differential inclusion with nonlocal integral condition is studied. The maximal and minimal solutions will be studied.
Ahmed M.A. El-Sayed , Eman M.A. Hamdallah , Hameda M. A. Alama   +2 more
doaj   +1 more source

Higher-spin initial data in twistor space with complex stargenvalues

Journal of High Energy Physics, 2020
This paper is a supplement to and extension of arXiv:1903.01399. In the internal twistor space of the 4D Vasiliev’s higher-spin gravity, we study the star-product eigenfunctions of number operators with generic complex eigenvalues.
Yihao Yin
doaj   +1 more source

A method of generating a random optical field using the Karhunen-Loeve expansion to simulate atmospheric turbulence [PDF]

Компьютерная оптика, 2020
It is proposed to use the random field generation in the numerical simulation of the propagation of radiation through a random medium using method based on the Karhunen–Loeve expansion with various types of correlation operators to describe turbulence ...
Svetlana Khonina, Sergey Volotovsky, Mikhail Kirilenko   +2 more
doaj   +1 more source

Analysis and methodology of determining the norm of eigenfunctions as a limit transition in the scalar product in the spectral Stourm-Louvile problem for a photonic one-dimensional crystal

Вісник Харківського національногоуніверситету імені В.Н. Каразіна. Серія: Радіофізика та електроніка, 2023
Relevance The last of the decades (approximately from the 90s of the 20th century) to rapid grow of photonics. That's why, firstly, relevance this work is related to relevance diffraction problems for the structures of optics ranges (photonic crystal ...
О.V. Kazanko, О.E. Penkina
doaj   +1 more source