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Wyszukujesz frazę "Green's function" wg kryterium: Temat


Tytuł:
Extremal plurisubharmonic functions
Autorzy:
Cegrell, Urban
Thorbiörnson, Johan
Powiązania:
https://bibliotekanauki.pl/articles/1311246.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
extremal plurisubharmonic function
pluricomplex Green function
Opis:
We study different notions of extremal plurisubharmonic functions.
Źródło:
Annales Polonici Mathematici; 1996, 63, 1; 63-69
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On definitions of the pluricomplex Green function
Autorzy:
Edigarian, Armen
Powiązania:
https://bibliotekanauki.pl/articles/1294575.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
pluricomplex Green function
Blaschke product
Riesz representation
Opis:
We give several definitions of the pluricomplex Green function and show their equivalence.
Źródło:
Annales Polonici Mathematici; 1997, 67, 3; 233-246
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximation polynomiale et extension holomorphe avec croissance sur une variété algébrique
Autorzy:
Zeriahi, A.
Powiązania:
https://bibliotekanauki.pl/articles/1311243.pdf
Data publikacji:
1996
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Green function
L² estimation
approximation
growth
extension
Opis:
We first give a general growth version of the theorem of Bernstein-Walsh-Siciak concerning the rate of convergence of the best polynomial approximation of holomorphic functions on a polynomially convex compact subset of an affine algebraic manifold. This can be considered as a quantitative version of the well known approximation theorem of Oka-Weil. Then we give two applications of this theorem. The first one is a generalization to several variables of Winiarski's theorem relating the growth of an entire function to the rate of convergence of its best polynomial approximation; the second application concerns the extension with growth of an entire function from an algebraic submanifold to the whole space.
Źródło:
Annales Polonici Mathematici; 1996, 63, 1; 35-50
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Pressure Radiated by a Circular Membrane Into the Quarter-Space
Autorzy:
Rdzanek, W. P.
Szemela, K.
Pieczonka, D.
Powiązania:
https://bibliotekanauki.pl/articles/177368.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic pressure
Fraunhoffer's zone
Green function
circular membrane
Opis:
The Neumann boundary value problem for the Helmholtz equation within the quarter-space has been considered in this paper. The Green function has been used to find the acoustic pressure amplitude as the approximation valid within the Fraunhoffer’s zone for some time-harmonic steady state processes. The low fluid loading has been assumed and the acoustic attenuation has been neglected. It has also been assumed that the vibration velocity of the acoustic particles is small as compared with the sound velocity in the gaseous medium.
Źródło:
Archives of Acoustics; 2011, 36, 1; 121-139
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On symmetry of the pluricomplex Green function for ellipsoids
Autorzy:
Zwonek, Włodzimierz
Powiązania:
https://bibliotekanauki.pl/articles/1294653.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
pluricomplex Green function
Lempert function
complex ellipsoid
$k̃_D$-geodesic
Opis:
We show that in the class of complex ellipsoids the symmetry of the pluricomplex Green function is equivalent to convexity of the ellipsoid.
Źródło:
Annales Polonici Mathematici; 1997, 67, 2; 121-129
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free and forced vibrations of Timoshenko beams described by single difference equation
Drgania własne i wymuszone belki Timoshenki opisane jednym równaniem różniczkowym
Autorzy:
Majkut, L.
Powiązania:
https://bibliotekanauki.pl/articles/280257.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
Timoshenko beam
Green function
boundary conditions
forced vibrations
Opis:
In the paper, a new approach to description of the Timoshenko beam free and forced vibrations by a single equation is proposed. The solution to such an equation is a function of vibration amplitudes. The boundary conditions corresponding to such a description of the beam vibration are also given. It was proved that the form of solution to the differential equation depends on the vibration frequency. The change of the solution form occurs when the frequency crosses a specific value omega = pierwiastek z GkA / (pI). The correctness of proposed description was checked through the analysis of free vibration frequencies and amplitudes of forced vibrations with different boundary conditions as well as comparison with the results of finite element analysis.
W pracy zaproponowano, nowe podejście do opisu drgań własnych i wymuszonych belki Timoshenki przez jedno równanie różniczkowe. Rozwiązaniem takiego równania jest funkcja amplitud drgań. Podano również równania opisujące warunki brzegowe odpowiednie do takiego opisu drgań. Udowodniono, że forma rozwiązania równania różniczkowego zależy od analizowanej częstości drgań. Zmiana formy rozwiązania zmienia się, gdy częstość osiąga określoną w pracy wartość omega = pierwiastek z GkA / (pI). Poprawność zaproponowanego opisu sprawdzono przez analizę częstości drgań własnych i amplitudy drgań wymuszonych belek z różnymi warunkami brzegowymi i porównaniem z wynikami otrzymanymi z analizy MES belki.
Źródło:
Journal of Theoretical and Applied Mechanics; 2009, 47, 1; 193-210
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundary element modelling of wave diffraction by interaction with wave-offshore structure and dredged region
Autorzy:
Kim, S. D.
Lee, H. J.
Powiązania:
https://bibliotekanauki.pl/articles/259525.pdf
Data publikacji:
2010
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Submarine pit
Green function
boundary integral approach
breakwater
Opis:
The purpose of this study is to estimate the wave height at the front face of breakwater (Refracted breakwater and Straight breakwater), when dredging like the submarine pit is performed in the distant offshore from outer breakwater. The wave field of the problem is considered to be two dimensional planes and the configuration of the pit region is designated by a single horizontal long-rectangular system. The numerical approach uses the Green function based on the boundary integral approach. The results of the present numerical works are illustrated by applying the normal and inclined incidence. It is shown that in the case of normal incidence, the ratio of wave height reduction at the front face of both types of breakwaters is approximately more than 20% due to the effect of the submarine pit on the sea bed. Furthermore, regardless of the type of breakwater and the difference in incident wave angles, the ratio of wave height was shown to be reduced.
Źródło:
Polish Maritime Research; 2010, 2; 67-71
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quasi-Green’s function approach to fundamental frequency analysis of elastically supported thin circular and annular plates with elastic constraints
Autorzy:
Żur, K. K.
Powiązania:
https://bibliotekanauki.pl/articles/280490.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
quasi-Green's function
ring supports
movable edges
elastic constraints
Opis:
Free vibration analysis of homogeneous and isotropic thin circular and annular plates with discrete elements such as elastic ring supports is considered. The general form of quasi- -Green’s function for thin circular and annular plates is obtained. The nonlinear characteristic equations are defined for thin circular and annular plates with different boundary conditions and different combinations of the core and support radius. The continuity conditions at the ring supports are omitted based on the properties of Green’s function. The fundamental frequency of axisymmetric vibration has been calculated using the Newton-Raphson method and calculation software. The obtained results are compared with selected results presented in literature. The exact frequencies of vibration presented in a non-dimensional form can serve as benchmark values for researchers to validate their numerical methods when applied for uniform thin circular and annular plate problems.
Źródło:
Journal of Theoretical and Applied Mechanics; 2017, 55, 1; 87-101
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat conduction problem in a two-layered hollow cylinder by using the Greens function method
Autorzy:
Kukla, S.
Siedlecka, U.
Powiązania:
https://bibliotekanauki.pl/articles/122646.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
heat conduction problem
two-layered cylinder
Green's function method
Opis:
In this paper, a solution of the heat conduction problem in a two-layered hollow cylinder by using the Green’s function method is presented. The considerations concern the heat conduction in the radial direction while taking into account time-dependent boundary conditions. The continuity condition of the temperature at the dividing surface of the layers is written in the form of a Volterra integral equation.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 2; 45-50
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Equality cases for condenser capacity inequalities under symmetrization
Autorzy:
Betsakos, Dimitrios
Pouliasis, Stamatis
Powiązania:
https://bibliotekanauki.pl/articles/747114.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej. Wydawnictwo Uniwersytetu Marii Curie-Skłodowskiej
Tematy:
Steiner symmetrization
Schwarz symmetrization
polarization
condenser
capacity
Green function
Opis:
It is well known that certain transformations decrease the capacity of a condenser. We prove equality statements for the condenser capacity inequalities under symmetrization and polarization without connectivity restrictions on the condenser and without regularity assumptions on the boundary of the condenser.
Źródło:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica; 2012, 66, 2
0365-1029
2083-7402
Pojawia się w:
Annales Universitatis Mariae Curie-Skłodowska, sectio A – Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phonon-Induced Thermodynamic Properties of Ultra-narrow Wires
Autorzy:
Ilić, D.
Šetrajčić, J.
Jaćimovski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1029824.pdf
Data publikacji:
2018-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
Phonons
ultra-narrow wire
the Green function
thermodynamics
specific heat
Opis:
In this paper, we investigated the influence of size effect on thermodynamic properties of ultra-narrow wires with a simple cubic lattice, by means of two-time dependent Green functions method, adjusted to confined crystalline structures. Poles of Green functions, which defining phonon spectra, are found by solving the secular equation. For different boundary parameters, this problem is presented graphically. The temperature behavior of ultra-narrow wire thermal capacitance is compared to that of bulk structures. It turned out that in low-temperature region thermal capacitance of the ultra-narrow wire is notably lower than in the corresponding bulk sample. How this fact reflects the thermal, conducting and superconducting properties of materials, is discussed in the conclusion.
Źródło:
Acta Physica Polonica A; 2018, 133, 1; 57-62
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of an lp –perturbation on Hardy-Sobolev inequality with singularity a curve
Autorzy:
Ijaodoro, Idowu Esther
Thiam, El Hadji Abdoulaye
Powiązania:
https://bibliotekanauki.pl/articles/2050964.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Hardy-Sobolev inequality
positive minimizers
parametrized curve
mass
Green function
Opis:
We consider a bounded domain $\Omega~\text{of}~\mathbb{R}^{N}, N \geq 3, h \text{and} b$ continuous functions on $\Omega$. Let $Gamma$ be a closed curve contained in $\Omega$. We study existence of positive solutions $u \in H_{0}^{1}(\Omega)$ to the perturbed Hardy-Sobolev equation: $$-\Delta{}u + hu + bu^{1+\delta} = \rho_{\Gamma}^{-\sigma} u^{2_{\sigma}^{\star}-1}~\text{in}~\Omega,$$ where $2_{\sigma}^{\star} := \frac{2(N-\sigma)}{N-2}$ is the critical Hardy-Sobolev exponent $\sigma \in [0,2), 0 < \delta < \frac{4}{N-2}$ and $\rho_{\Gamma}$ is the distance function to $\Gamma$. We show that the existence of minimizers does not depend on the local geometry of $\Gamma$ nor on the potential $h$. For $N = 3$, the existence of ground-state solution may depends on the trace of the regular part of the Green function of $-\Delta + h$ and or on $b$. This is due to the perturbative term of order $1 + \delta$.
Źródło:
Opuscula Mathematica; 2021, 41, 2; 187-204
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jensen measures, hyperconvexity and boundary behaviour of the pluricomplex Green function
Autorzy:
Carlehed, Magnus
Cegrell, Urban
Wikström, Frank
Powiązania:
https://bibliotekanauki.pl/articles/1294170.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
hyperconvexity
Jensen measures
Reinhardt domains
Hartogs' triangle
pluricomplex Green function
Opis:
We characterise hyperconvexity in terms of Jensen measures with barycentre at a boundary point. We also give an explicit formula for the pluricomplex Green function in the Hartogs triangle. Finally, we study the behaviour of the pluricomplex Green function g(z,w) as the pole w tends to a boundary point.
Źródło:
Annales Polonici Mathematici; 1999, 71, 1; 87-103
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nieuporządkowany metamagnetyk z ferro- i antyferromagnetycznymi oddziaływaniami wymiany Część I. Procedura uśredniania funkcji Greena
A dilute metamagnet with ferro- and antiferromagnetic exchange interactions Part I. The Green function averaging procedure
Autorzy:
Pikuła, R.
Kirkiewicz, J.
Bieg, B.
Powiązania:
https://bibliotekanauki.pl/articles/906829.pdf
Data publikacji:
2006
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
nieuporządkowany metamagnetyk
fluktuacje strukturalne
funkcja Greena
dilute metamagnet
structural fluctuations
Green function
Opis:
W oparciu o technikę rozwinięć kumulantowych przedstawiono matematyczny opis dwupodsieciowego, nieuporządkowanego metamagnetyka z ferro- i anty-ferromagnetycznymi oddziaływaniami wymiany. Otrzymana postać uśrednionej funkcji Greena jest podstawą do analizy wpływu fluktuacji strukturalnych na statystyczne własności układu.
Using the Cumulant Expansion Technique there has been presented the mathematical description of two-sublattice dilute metamagnet with ferro- and antiferromagne-tic exchange interactions. The derived form of the averaged Green function is the base for the analysis of the influence of structural fluctuations on the statistical properties of the system.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2006, 8 (80); 59-75
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wieners type regularity criteria on the complex plane
Autorzy:
Siciak, Józef
Powiązania:
https://bibliotekanauki.pl/articles/1294812.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
subharmonic functions
logarithmic potential theory
Green function
regular points
Hölder Continuity Property
Opis:
We present a number of Wiener's type necessary and sufficient conditions (in terms of divergence of integrals or series involving a condenser capacity) for a compact set E ⊂ ℂ to be regular with respect to the Dirichlet problem. The same capacity is used to give a simple proof of the following known theorem [2, 6]: If E is a compact subset of ℂ such that $d(t^{-1}E ∩ {|z-a| ≤ 1}) ≥ const > 0$ for 0 < t ≤ 1 and a ∈ E, where d(F) is the logarithmic capacity of F, then the Green function of ℂ \ E with pole at infinity is Hölder continuous.
Źródło:
Annales Polonici Mathematici; 1997, 66, 1; 203-221
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of Darboux transformation to multidimensinal inhomogeneous problems
Autorzy:
Kwiatkowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1938593.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska
Tematy:
Darboux transform
Green function
interwine relation
ladder operator
inhomogeneous partial differential equation
Opis:
General properties of ladder operators applied to inhomogeneous problems are studied in the context of their usefulness for solving practical problems with stress put on the possibility of embedding the interwine relation onto a wider class of operators. From those general remarks an algorithm using the Darboux transform for construction of the Green function for linear partial differential equations is formed and a sample implementation thereof is shown along with some examples of solutions.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2016, 20, 2; 187-195
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherent potential approximation technique in a simple example of resistivity calculations for binary alloys
Autorzy:
Wołoszyn, M.
Maksymowicz, A. Z.
Powiązania:
https://bibliotekanauki.pl/articles/1931584.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
Coherent Potential Approximation
Green function technique
binary alloy
density of states
resistivity
Opis:
Technique of the Coherent Potential Approximation applied for calculations of the density of states in binary alloys Ax B(1-x) is presented. Results of the calculations are also used to find the residual resistivity of the system versus concentration x.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 4; 669-680
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nieuporządkowany metamagnetyk z ferro- i antyferromagnetycznymi oddziaływaniami wymiany. Część II. Analiza fluktuacji strukturalnych
A dilute metamagnet with ferro- and antiferromagnetic exchange interactions. Part II. The structural fluctuations analysis
Autorzy:
Pikuła, R.
Kirkiewicz, J.
Bieg, B.
Powiązania:
https://bibliotekanauki.pl/articles/906827.pdf
Data publikacji:
2006
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
nieuporządkowany metamagnetyk
fluktuacje strukturalne
funkcja Greena
dilute metamagnet
structural fluctuations
Green function
Opis:
Dokonano analizy wpływu fluktuacji strukturalnych na własności nieuporządkowanego metamagnetyka. Stwierdzono, że przybliżenie wysokich i niskich koncentracji atomów magnetycznych prowadzi do bardzo zbliżonych rezultatów, a największy wpływ na wielkości fizyczne pochodzi od najniższych kwadratowych fluktuacji.
There has been analysed the influence of the structural fluctuations on the properties of a dilute metamagnet. The high- and low-concentration approximations have been found to give very close results and the most important influence on the physical quantities originates from the lowest - square fluctuations.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2006, 8 (80); 77-91
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free vibration to a system of cantilever nanobeams
Autorzy:
Ciekot, A.
Kukla, S.
Powiązania:
https://bibliotekanauki.pl/articles/122838.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
cantilever nanobeams
free vibration
Green's function method
drgania swobodne
metoda funkcji Greena
Opis:
This paper presents a solution to the free vibration problem of a system of two cantilever nanobeams. The nanobeams of the system are axially loaded and coupled by discrete translational springs. The solution of the problem by using the Green’s function method has been obtained. A numerical example shows the effect of the small scale on free vibration frequencies of the nanobeam system considered.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 3; 29-36
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free longitudinal vibration of a double-nanorod system
Autorzy:
Ciekot, A.
Kukla, S.
Powiązania:
https://bibliotekanauki.pl/articles/122520.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
double-nanorod system
longitudinal vibration
Green's function method
drgania podłużne
metoda funkcji Greena
Opis:
In this paper a solution to the problem of the free longitudinal vibration of a double-nanorod-system (DNRS) is presented. The nanorods of the system are coupled by many translational springs. The clamped-clamped and clamped-free boundary conditions are employed. The problem of vibration is solved by using the Green’s function method. The natural frequencies were numerically calculated.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 2; 15-22
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the existence of positive continuous solutions for some polyharmonic elliptic systems on the half space
Autorzy:
Zine El Abidine, Z.
Powiązania:
https://bibliotekanauki.pl/articles/255368.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
polyharmonic elliptic system
Green function
Kato class
positive continuous solution
Schauder fixed point theorem
Opis:
We study the existence of positive continuous solutions of the nonlinear polyharmonic system (-Δ)mu + λqg(v) = 0, (-Δ)mv + μpf(u) = 0 in the half space [formula] where m ≥1 and n>2m.The nonlinear term is required to satisfy some conditions related to the Kato class [formula]. Our arguments are based on potential theory tools associated to (-Δ)m and properties of functions belonging to [formula].
Źródło:
Opuscula Mathematica; 2012, 32, 1; 91-113
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of ship motions via a three-dimensional time-domain method following a quad-tree adaptive mesh technique
Autorzy:
Zhang, Teng
Ren, Junsheng
Liu, Lu
Powiązania:
https://bibliotekanauki.pl/articles/259860.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
Froude-Krylov forces
adaptive mesh technique
analytical
transient free surface Green function
precise integration method
Opis:
A three-dimensional (3D) time-domain method is developed to predict ship motions in waves. To evaluate the Froude- Krylov (F-K) forces and hydrostatic forces under the instantaneous incident wave profile, an adaptive mesh technique based on a quad-tree subdivision is adopted to generate instantaneous wet meshes for ship. For quadrilateral panels under both mean free surface and instantaneous incident wave profiles, Froude-Krylov forces and hydrostatic forces are computed by analytical exact pressure integration expressions, allowing for considerably coarse meshes without loss of accuracy. And for quadrilateral panels interacting with the wave profile, F-K and hydrostatic forces are evaluated following a quad-tree subdivision. The transient free surface Green function (TFSGF) is essential to evaluate radiation and diffraction forces based on linear theory. To reduce the numerical error due to unclear partition, a precise integration method is applied to solve the TFSGF in the partition computation time domain. Computations are carried out for a Wigley hull form and S175 container ship, and the results show good agreement with both experimental results and published results.
Źródło:
Polish Maritime Research; 2020, 1; 29-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Existence of positive continuous weak solutions for some semilinear elliptic eigenvalue problems
Autorzy:
Zeddini, Noureddine
Sari, Rehab Saeed
Powiązania:
https://bibliotekanauki.pl/articles/2216186.pdf
Data publikacji:
2022
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Green function
Kato class
nonlinear elliptic systems
positive solution
maximum principle
Schauder fixed point theorem
Opis:
Let D be a bounded $C^(1,1)$ -domain in $R^d$, d ≥ 2. The aim of this article is twofold. The first goal is to give a new characterization of the Kato class of functions $K(D)$ that was defined by $N$. Zeddini for $d = 2$ and by $H$. Mâagli and M. Zribi for $d ≥ 3$ and adapted to study some nonlinear elliptic problems in $D$. The second goal is to prove the existence of positive continuous weak solutions, having the global behavior of the associated homogeneous problem, for sufficiently small values of the nonnegative constants $λ$ and $μ$ to the following system $Δu = λf(x, u, v)$, $Δv = μg(x, u, v)$ in D, $u = ϕ_1$ and $v = ϕ_2$ on $∂D$, where $ϕ_1$ and $ϕ_2$ are nontrivial nonnegative continuous functions on $∂D$. The functions $f$ and g are nonnegative and belong to a class of functions containing in particular all functions of the type $f(x, u, v) = p(x)u^(α) h_1 (v)$ and $g(x, u, v) = q(x)h_2 (u)v^β$ with $α ≥ 1$, $β ≥ 1$, $h_1$, $h_2$ are continuous on $[0,∞)$ and $p$, $q$ are nonnegative functions in $K(D)$.
Źródło:
Opuscula Mathematica; 2022, 42, 3; 489-519
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Greens functions and existence of solutions of nonlinear fractional implicit difference equations with Dirichlet boundary conditions
Autorzy:
Cabada, Alberto
Dimitrov, Nikolay D.
Jonnalagadda, Jagan Mohan
Powiązania:
https://bibliotekanauki.pl/articles/29519501.pdf
Data publikacji:
2024
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
fractional difference
Dirichlet conditions
Green’s function
existence of solutions
Opis:
This article is devoted to deduce the expression of the Green’s function related to a general constant coefficients fractional difference equation coupled to Dirichlet conditions. In this case, due to the points where some of the fractional operators are applied, we are in presence of an implicit fractional difference equation. So, due to such a property, it is more complicated to calculate and manage the expression of the Green’s function than in the explicit case studied in a previous work of the authors. Contrary to the explicit case, where it is shown that the Green’s function is constructed as finite sums, the Green’s function constructed here is an infinite series. This fact makes necessary to impose more restrictive assumptions on the parameters that appear in the equation. The expression of the Green’s function will be deduced from the Laplace transform on the time scales of the integers. We point out that, despite the implicit character of the considered equation, we can have an explicit expression of the solution by means of the expression of the Green’s function. These two facts are not incompatible. Even more, this method allows us to have an explicit expression of the solution of an implicit problem. Finally, we prove two existence results for nonlinear problems, via suitable fixed point theorems.
Źródło:
Opuscula Mathematica; 2024, 44, 2; 167-195
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some constructions of linear extensions of dynamical systems
Pewne konstrukcje liniowych rozszerzeń układów dynamicznych
Autorzy:
Pączko, D.
Powiązania:
https://bibliotekanauki.pl/articles/87312.pdf
Data publikacji:
2011
Wydawca:
Politechnika Śląska. Wydawnictwo Politechniki Śląskiej
Tematy:
układ dynamiczny
rozszerzenie liniowe
równanie różniczkowe
funkcja Greena
dynamical system
linear extension
differential equation
Green function
Opis:
The paper presents a method to transform two weakly regular systems to one regular system. Additionally, it is proved that there is no linear change of variables reducing the extension of a dynamical system to a conjugate system where the number of normal variables is three.
Wartykule przedstawiono metodę doprowadzenia dwóch układów słabo regularnych do jednego układu regularnego. Dodatkowo pokazano, że niemożliwe jest doprowadzenie liniowego rozszerzenia układu dynamicznego do układu sprzężonego, w przypadku gdy liczba zmiennych normalnych wynosi trzy.
Źródło:
Zeszyty Naukowe. Matematyka Stosowana / Politechnika Śląska; 2011, 1; 37-49
2084-073X
Pojawia się w:
Zeszyty Naukowe. Matematyka Stosowana / Politechnika Śląska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sign-changing Lyapunov functions in regularity of linear extensions of dynamical systems on a torus
Autorzy:
Tkocz-Piszczek, E.
Powiązania:
https://bibliotekanauki.pl/articles/255119.pdf
Data publikacji:
2008
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
invariant torus
Green's function of a problem of invariant toruses
regularity of linear extensions of dynamical systems
Opis:
In this paper we consider some sign-changing Lyapunov function in research on regularity of sets of linear extensions of dynamical systems on a torus.
Źródło:
Opuscula Mathematica; 2008, 28, 1; 93-101
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bernstein and van der Corput-Schaake type inequalities on semialgebraic curves
Autorzy:
Baran, M.
Pleśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/1219584.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Bernstein and van der Corput-Schaake type inequalities
semialgebraic curves
algebraic manifolds
pluricomplex Green function
Lipschitz functions
Opis:
We show that in the class of compact, piecewise $C^1$ curves K in $ℝ^n$, the semialgebraic curves are exactly those which admit a Bernstein (or a van der Corput-Schaake) type inequality for the derivatives of (the traces of) polynomials on K.
Źródło:
Studia Mathematica; 1997, 125, 1; 83-96
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the blowing up solutions of the 4-d general q-Kuramoto-Sivashinsky equation with exponentially “dominated” nonlinearity and singular weight
Autorzy:
Baraket, Sami
Mahdaoui, Safia
Ouni, Taieb
Powiązania:
https://bibliotekanauki.pl/articles/29519212.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
singular limits
Green’s function
nonlinearity
gradient
nonlinear domain decomposition method
Opis:
Let Ω be a bounded domain in $ \mathbb{R}^4 $ with smooth boundary and let $ x^1, x^2, . . . , x^m $ be m-points in Ω. We are concerned with the problem $ \Delta^2 u - H(x, u, D^k u)=\rho^4 \prod_{i=1}^n | x - p_i |^{4 \alpha_i } f(x)g(u), $ where the principal term is the bi-Laplacian operator, $ H(x, u, D^k u)$ is a functional which grows with respect to $ Du $ at most like $ |Du|^q, 1 ≤ q ≤ 4, f : Ω → [0,+∞[ $ is a smooth function satisfying f(pi) > 0 for any i = 1, . . . , n, $ α_i $ are positives numbers and $ g : \mathbb{R} → [0,+∞[ $ satisfy $ |g(u)| ≤ ce^u $. In this paper, we give sufficient conditions for existence of a family of positive weak solutions $ (u_ρ)_{ρ>0} $ in Ω under Navier boundary conditions u = Δu = 0 on ∂Ω. The solutions we constructed are singular as the parameters ρ tends to 0, when the set of concentration $ S = {x^1, . . . , x^m} ⊂ Ω $ and the set $ Λ := {p_1, . . . , p_n} ⊂ Ω $ are not necessarily disjoint. The proof is mainly based on nonlinear domain decomposition method.
Źródło:
Opuscula Mathematica; 2023, 43, 1; 5-18
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Region of existence of multiple solutions for a class of robin type four-point bvps
Autorzy:
Verma, Amit K.
Urus, Nazia
Agarwal, Ravi P.
Powiązania:
https://bibliotekanauki.pl/articles/2052065.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Green’s function
monotone iterative technique
maximum principle
multi-point problem
Opis:
This article aims to prove the existence of a solution and compute the region of existence for a class of four-point nonlinear boundary value problems (NLBVPs) defined as \[ \begin{array}{lr} -u^{\prime\prime}(x) = \psi(x,u,u^{\prime}), & x \in (0,1) \\ u^{\prime}(0) = \lambda_{1}u(\xi), & u^{\prime}(1) = \lambda_{2}u(\eta) \end{array} \] where $I = [0, 1], 0 < \xi \leq \eta < 1 \text{ and } \lambda_{1} ,\lambda_{2} > 0$. The nonlinear source term $\psi \in C(I \times \mathbb{R}^{2}, \mathbb{R})$ is one sided Lipschitz in $u$ with Lipschitz constant $L_{1}$ and Lipschitz in $u^{\prime}$, such that $\vert \psi(x, u, u^{\prime}) - \psi(x, u, v^{\prime})\vert$. We develop monotone iterative technique (MI-technique) in both well ordered and reverse ordered cases. We prove maximum, anti-maximum principle under certain assumptions and use it to show the monotonic behaviour of the sequences of upper-lower solutions. The sufficient conditions are derived for the existence of solution and verified for two examples. The above NLBVPs is linearised using Newton’s quasilinearization method which involves a parameter k equivalent to $\text{max}_{u} \frac{\delta\psi}{\delta_{u}}$. We compute the range of $k$ for which iterative sequences are convergent.
Źródło:
Opuscula Mathematica; 2021, 41, 4; 571-600
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact and approximate controllability conditions for the micro-swimmers deflection governed by electric field on a plane: The Green’s function approach
Autorzy:
Khurshudyan, A. Zh.
Powiązania:
https://bibliotekanauki.pl/articles/229564.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
run
tumble
micro-swimmers
Green’s function of nonlinear equation
discontinuous
Opis:
We study the exact and approximate controllabilities of the Langevin equation describing the Brownian motion of particles with a white noise. The Langevin equation is shown to describe also the bacterial run-and-tumble motion. Applying the Green’s function approach to the Green’s function representation of the Langevin equation, we obtain necessary and sufficient conditions for exact controllability in the form of a finite-dimensional problem of moments. For the approximate controllability, we obtain only sufficient conditions. The sets of resolving controls are characterized in both cases. The theoretical derivations are supported by a numerical analysis.
Źródło:
Archives of Control Sciences; 2018, 28, 3; 335-347
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of compact subsets of algebraic varieties in terms of Bernstein type inequalities
Autorzy:
Baran, M.
Pleśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/1206009.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
pluricomplex Green function
Siciak extremal function
traces of polynomials on semialgebraic sets
Zariski dimension
Bernstein and van der Corput-Schaake type inequalities
Opis:
We show that in the class of compact sets K in $ℝ^n$ with an analytic parametrization of order m, the sets with Zariski dimension m are exactly those which admit a Bernstein (or a van der Corput-Schaake) type inequality for tangential derivatives of (the traces of) polynomials on K.
Źródło:
Studia Mathematica; 2000, 141, 3; 221-234
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Polynomial inequalities on algebraic sets
Autorzy:
Baran, M.
Pleśniak, W.
Powiązania:
https://bibliotekanauki.pl/articles/1206008.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Bernstein-Walsh and tangential Markov type inequalities on algebraic sets
pluricomplex Green function
traces of polynomials on algebraic sets
Siciak's extremal function
Opis:
We give an estimate of Siciak's extremal function for compact subsets of algebraic varieties in $ℂ^n$ (resp. $ℝ^n$). As an application we obtain Bernstein-Walsh and tangential Markov type inequalities for (the traces of) polynomials on algebraic sets.
Źródło:
Studia Mathematica; 2000, 141, 3; 209-219
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surface Green’s function of a soft elastomer with the gravity effect
Autorzy:
Liang, Xiaodong
Liu, Junxiu
Xu, Peibao
Li, Kai
Powiązania:
https://bibliotekanauki.pl/articles/280502.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
surface Green’s function
gravity
distributed pressure
soft materials
neo-Hookean model
Opis:
Gravity can play a tremendous effect on deformation of rubberlike materials and biological soft tissues. In this paper, considering the gravity effect, we proposed a surface Green’s function of a soft elastomer based on the neo-Hookean model. The proposed surface Green’s function is applied to analyze the elastic deformation of a soft elastomer subjected to uniform pressure. The surface normal displacement of the soft elastomer is calculated and the results show that gravity has a large impact on the surface deformation of the elastomer. Generally, the surface normal displacement decreases with the increasing gravitational force.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 1; 35-44
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Greens function for Euler-Bernoulli beams by means of the Fredholm Alternative Theorem
Autorzy:
Hozhabrossadati, S. M.
Sani, A. A.
Mofid, M.
Powiązania:
https://bibliotekanauki.pl/articles/973616.pdf
Data publikacji:
2013
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
Fredholm Alternative Theorem
modified Green’s function
resonance
Euler-Bernoulli beam
rezonans
Opis:
This paper presents the Green's function for a uniform thin beam which is assumed to obey the Euler-Bernoulli theory at resonant condition. The beam under study has a simple support at one end and a sliding support at the other. First, the differential equation governing the free vibration of the beam is obtained in the frequency domain using the Fourier transform. Then, we try to find the corresponding Green's function of the problem. But a contradiction occurs due to the special properties of resonance. In order to overcome this hurdle, the Fredholm Alternative Theorem is utilized. Remarkably, it is shown that this theorem, by adding a particular term to the Green's function, can remedy this problem and the modified Green's function is consequently established. Moreover, the deformation function of the beam is found in an integral equation form. Some diagrams and tables conclude this study.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2013, 12, 3; 55-67
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Approximate controllability of second order infinite dimensional systems
Autorzy:
Klamka, Jerzy
Khurshudyan, Asatur Zh.
Powiązania:
https://bibliotekanauki.pl/articles/1409079.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
infinite dimensional systems
approximate controllability
Green’s function approach
flexible Kirchhoff–Love plate
Opis:
In the paper approximate controllability of second order infinite dimensional system with damping is considered. Applying linear operators in Hilbert spaces general mathematical model of second order dynamical systems with damping is presented. Next, using functional analysis methods and concepts, specially spectral methods and theory of unbounded linear operators, necessary and sufficient conditions for approximate controllability are formulated and proved. General result may be used in approximate controllability verification of second order dynamical system using known conditions for approximate controllability of first order system. As illustrative example using Green function approach approximate controllability of distributed dynamical system is also discussed.
Źródło:
Archives of Control Sciences; 2021, 31, 1; 165-184
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Matrix Greens function of double-diffusivity problem and its applications to problems with inner point source
Autorzy:
Chaplya, Yevhen
Chernukha, Olha
Bilushchak, Yurii
Powiązania:
https://bibliotekanauki.pl/articles/1954454.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
Green’s function
double-diffusivity
initial-boundary value problem
point mass source
random coordinate
Opis:
The matrix Green’s function of the initial-boundary value problem of admixture double-diffusivity is defined. The initial-boundary value problem with a point source is formulated for the matrix elements for determination of the matrix Green’s function. Formulae for matrix elements are obtained and the behavior of Green’s functions is investigated. It is shown that the surface generated by the Green’s function has a typical sharp peak in the vicinity of the point of action of the point mass source, and in the vicinity of the top boundary of the layer ,the values of the second element of the Green’s function are times higher than the values of the first one the state of which is corresponding to the quick migration way. On this basis the solutions of the initial-boundary value problems under the action of the internal point source of mass are found. The cases of the deterministic source as well as stochastic ones under uniformand triangular distributions of the coordinate of the mass source location are considered.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2019, 23, 1; 75-99
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Time Domain Model of GPR Antenna Radiation Pattern
Autorzy:
Edemsky, F.
Popov, A.
Zapunidi, S.
Powiązania:
https://bibliotekanauki.pl/articles/226318.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
subsurface sensing
ground penetrating radar
electromagnetic pulse radiation
ground-air interface
time-domain Green function
spatio-temporal radiation pattern
inverse problem
deconvolution
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 3; 407-411
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Covariant differential operators and Greens functions
Autorzy:
Engliš, Miroslav
Peetre, Jaak
Powiązania:
https://bibliotekanauki.pl/articles/1294789.pdf
Data publikacji:
1997
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
covariant differential operator
Laplace operator
Green's function
Hayman-Korenblum fomula
Bojarski's theorem
Bol's lemma
covariant Cauchy-Riemann operator
dilogarithm
trilogarithm
general nonsense
Opis:
The basic idea of this paper is to use the covariance of a partial differential operator under a suitable group action to determine suitable associated Green's functions. For instance, we offer a new proof of a formula for Green's function of the mth power $Δ^m$ of the ordinary Laplace's operator Δ in the unit disk found in a recent paper (Hayman-Korenblum, J. Anal. Math. 60 (1993), 113-133). We also study Green's functions associated with mth powers of the Poincaré invariant Laplace operator . It turns out that they can be expressed in terms of certain special functions of which the dilogarithm (m = 2) and the trilogarithm (m = 3) are the simplest instances. Finally, we establish a relationship between $Δ^m$ and : the former is up to conjugation a polynomial of the latter.
Źródło:
Annales Polonici Mathematici; 1997, 66, 1; 77-103
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical solution of the dual phase lag equation describing the laser heating of thin metal film
Autorzy:
Ciesielski, M.
Powiązania:
https://bibliotekanauki.pl/articles/122626.pdf
Data publikacji:
2017
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
dual phase lag equation
laser heating process
analytical solution
Green's function method
transfer ciepła
laserowy proces ogrzewania
równanie z dwoma czasami opóźnień
metoda funkcji Greena
Opis:
Heat transfer processes occurring in the micro-domains can be described using the dual-phase lag equation (DPLE). This equation can be applied as a model of heating of the thin metal film subjected to the femtosecond laser pulse. In the paper, the 1D dual phase lag equation containing the additional internal heat source resulting from the laser pulse irradiation and supplemented by the appropriate boundary and initial conditions is considered. Appearing in this equation two lag times τq the phase lag of the heat flux) and τT (the phase lag of the temperature gradient) are taken into account. An analytical solution of this equation under the assumption that τT > τq is presented. The separation of the variables technique and the Green’s function method are used in order to find this solution. In the final part of the paper, the example of computations is presented.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2017, 16, 1; 33-40
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic Power Radiated by a System of Two Vibrating Circular Membranes Located at the Boundary of Three-Wall Corner Spatial Region
Autorzy:
Szemela, K.
Rdzanek, W. P.
Rdzanek, W. J.
Powiązania:
https://bibliotekanauki.pl/articles/176658.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
three-wall corner region
Green function
Neumann boundary value problem
modal analysis
asymmetric vibrations
vibration of an excited circular membrane
acoustic power
mutual interaction of sound sources
Opis:
Two vibrating circular membranes radiate acoustic waves into the region bounded by three infinite baffles arranged perpendicularly to one another. The Neumann boundary value problem has been inves- tigated in the case when both sources are embedded in the same baffle. The analyzed processes are time harmonic. The membranes vibrate asymmetrically. External excitations of different surface distributions and different phases have been applied to the sound sources’ surfaces. The influence of the radiated acoustic waves on the membranes’ vibrations has been included. The acoustic power of the sound sources system has been calculated by using a complete eigenfunctions system.
Źródło:
Archives of Acoustics; 2012, 37, 4; 463-473
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fizyczne podstawy metody interferometrii sejsmicznej
Physical derivation of the seismic interferometry method
Autorzy:
Czarny, R.
Powiązania:
https://bibliotekanauki.pl/articles/394167.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
interferometria sejsmiczna
funkcja Greena
korelacja wzajemna
akustyka odwróconego czasu
seismic interferometry
Green’s function
cross-correlation
time-reversed acoustics
Opis:
Interferometria sejsmiczna jest dynamicznie rozwijającą się metodą, której pierwsze zastosowania sięgają początków obecnego stulecia. Aktualnie znajduje coraz szersze zastosowanie w zagadnieniach m.in. obrazowania głębokich struktur ziemi oraz utworów przypowierzchniowych, monitorowania procesów wulkanicznych oraz analizowania wpływu silnych trzęsień ziemi na obiekty budowlane. Metoda ta pozwala na odtworzenie odpowiedzi impulsowej tzw. funkcji Greena ośrodka pomiędzy parą odbiorników na podstawie zarejestrowanych w tym samym czasie sejsmicznych pól falowych na tych odbiornikach. W wyniku odpowiednich operacji matematycznych metoda ta zamienia zarejestrowane na odbiornikach koherentne fale sejsmiczne o nieznanym czasie oraz miejscu ich wzbudzenia na układ tzw. wirtualnych źródeł emitujących sejsmiczne pole falowe z dowolnego odbiornika. W artykule przedstawiono fizyczne uzasadnienie wyników eksperymentu akustyki odwróconego czasu (ang. time-reversed acoustics) według Derode i in. (2003), które jest zarazem wytłumaczeniem metody interferometrii sejsmicznej. Eksperyment laboratoryjny w pierwszym etapie polegał na rejestracji akustycznego pola falowego wyemitowanego na brzegu naczynia wypełnionego cieczą i stalowymi prętami. Następnie rejestracje zostały odwrócone w czasie i wysłane powtórnie do wewnątrz naczynia i odebrany po przeciwnej stronie. Zarejestrowany na końcu sygnał okazał się zbliżony do sygnału wyemitowanego, pomimo przejścia przez ośrodek wielokrotnie rozpraszający. Doświadczenie to uzasadniono wykorzystując technikę korelacji wzajemnej (ang. cross-correlation), zasadę superpozycji pola falowego oraz zasadę wzajemności Rayleigha.
Seismic interferometry is a geophysical method which has been developing very rapidly over the last decade. It has been applied to image deep structures of the Earth as well as near-surface, monitor volcanic processes, geothermal reservoirs within exploitation, rock mass deformation induced by mining, landslides, ground water storage, ice sheet or the impact of strong earthquakes to buildings. The vast majority of these applications use ambient seismic noise as a seismic source. This method involves reconstructing thte impulse response, the socalled Green’s function, between pair of receivers based on the wave field registered by them. Using seismic interferometry with various data processing flows the registered coherent seismic waves by the receivers can be changed to virtual sources which are placed in the receiver locations. In the article, the physical derivation of the time-reversed acoustics experiment which was introduced by Derode et. al. (2003) is presented. This derivation also explains the seismic interferometry method. The laboratory experiment contained two phases. First, an acoustics signal was emitted into the medium with hundreds of scatterers (cube with liquid and rods) and registered on the opposite side of the medium. Then, registrations were reversed and emitted back. Finally, the wave field refocused exactly in the point of initial excitation. Derode et. al. explain these results using the cross-correlation technique, superposition and Rayleigh’s reciprocity principles.
Źródło:
Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN; 2017, 101; 195-202
2080-0819
Pojawia się w:
Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum simulations of band-to-band tunnelling in a type-II broken-gap superlattice diode
Autorzy:
Makowiec, Marcin
Kolek, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/2204215.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
type-II superlattice
broken-gap superlattice diode
band-to-band tunnelling
quantum transport
nonequilibrium Green’s function
twoband Hamiltonian
Opis:
In recent years, type-II superlattice-based devices have completed the offer of the electronic industry in many areas of applications. Photodetection is one of them, especially in the midinfrared wavelength range. It is due to the unique feature of a superlattice material, which is a tuneable bandgap. It is also believed that the dark current of superlattice-based photodetectors is strongly suppressed due to the suppression of the band-to-band tunnelling current in a superlattice material. This argument relies, however, on a semi-classical approach that treats superlattice as a bulk material with effective parameters extracted from the k·p analysis. In the paper, a superlattice device is analysed on a quantum level: the nonequilibrium Green’s function method is applied to the two-band Hamiltonian of the InAs/GaSb superlattice p-i-n diode. The analysis concentrates on the band-to-band tunnelling with the aim to validate the correctness of a semi-classical description of the phenomenon. The results of calculations reveal that in a superlattice diode, the inter-band tunnelling occurs only for certain values of energy and in-plane momentum, for which electronic and hole sub-bands cross. The transitions occurring for vanishing in-plane momentum produce resonances in the current-voltage characteristics - the feature which was reported in a few experimental observations. This scenario is quite different from that occurring in bulk materials, where there is a range of energy-momentum pairs for which the band-to-band tunnelling takes place, and so current-voltage characteristics are free from any resonances. However, simulations show that, while not justified for a detailed analysis, the semi-classical description can be applied to superlattice-based devices for an ‘order of magnitude’ estimation of the band-to-band tunnelling current.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144558
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heating control of a finite rod with a mobile source
Autorzy:
Jilavyan, Samvel H.
Grigoryan, Edmon R.
Khurshudyan, Asatur Zh.
Powiązania:
https://bibliotekanauki.pl/articles/1409386.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
null-controllability
mobile control
nonlinear constraints
triangular wave
rectangular wave
Green’s function approach
heuristic control
lack of exact controllability
Opis:
The Green’s function approach is applied for studying the exact and approximate null-controllability of a finite rod in finite time by means of a source moving along the rod with controllable trajectory. The intensity of the source remains constant. Applying the recently developed Green’s function approach, the analysis of the exact null-controllability is reduced to an infinite system of nonlinear constraints with respect to the control function. A sufficient condition for the approximate null-controllability of the rod is obtained. Since the exact solution of the system of constraints is a long-standing open problem, some heuristic solutions are used instead. The efficiency of these solutions is shown on particular cases of approximate controllability.
Źródło:
Archives of Control Sciences; 2021, 31, 2; 417-430
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distributed controllability of one-dimensional heat equation in unbounded domains: The Greens function approach
Autorzy:
Khurshudyan, Asatur Zh.
Powiązania:
https://bibliotekanauki.pl/articles/229527.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lack of controllability
exact controllability
approximate controllability
nullcontrollability
Green’s function
heuristic method
infinite system of algebraic equations
regularity
fully regularity
Opis:
We derive exact and approximate controllability conditions for the linear one-dimensional heat equation in an infinite and a semi-infinite domains. The control is carried out by means of the time-dependent intensity of a point heat source localized at an internal (finite) point of the domain. By the Green’s function approach and the method of heuristic determination of resolving controls, exact controllability analysis is reduced to an infinite system of linear algebraic equations, the regularity of which is sufficient for the existence of exactly resolvable controls. In the case of a semi-infinite domain, as the source approaches the boundary, a lack of L2-null-controllability occurs, which is observed earlier by Micu and Zuazua. On the other hand, in the case of infinite domain, sufficient conditions for the regularity of the reduced infinite system of equations are derived in terms of control time, initial and terminal temperatures. A sufficient condition on the control time, heat source concentration point and initial and terminal temperatures is derived for the existence of approximately resolving controls. In the particular case of a semi-infinite domain when the heat source approaches the boundary, a sufficient condition on the control time and initial temperature providing approximate controllability with required precision is derived.
Źródło:
Archives of Control Sciences; 2019, 29, 1; 57-71
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of heating curves of a rectangular busbar in different conditions of heat abstraction during the short-circuit heating
Autorzy:
Zaręba, M.
Powiązania:
https://bibliotekanauki.pl/articles/201224.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analytical methods
field theory
transient heat flow
short-circuit in leads
Green’s function
metody analityczne
teoria pola
nieustalony przepływ ciepła
funkcja Greena
Opis:
The paper compares heating curves for a rectangular busbar in the conditions of convective and adiabatic heat transfer during short-circuit heating. Different coefficients of heat transfer from the external surface of the busbar and different busbar cross-sections have been assumed. This has allowed determining the error value occurring when the adiabatic rather than convective boundary condition is presumed at short circuit. The analysis takes into account a change of resistivity in the temperature function. The respective boundary-initial problems have been solved with analytical methods using Green’s function. The calculated results show that no considerable errors occur for long-lasting short circuits with an adiabatic rather than convective boundary condition.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 79-85
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Problem on extremal decomposition of the complex plane
O problemie ekstremalnej dekompozycji płaszczyzny zespolonej
Autorzy:
Denega, Iryna
Powiązania:
https://bibliotekanauki.pl/articles/699882.pdf
Data publikacji:
2018
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
inner radius of domain, non-overlapping domains, radial system of points, separating transformation, quadratic differential, Green’s function
promień wewnętrzny obszaru, ekstremalna dekompozycja płaszczyzny zespolonej
Opis:
https://doi.org/10.26485/0459-6854/2018/68.3/6 Rozpatrujemy funkcjonał określony na układzie niezachodzących na siebie obszarów. Wynik dotyczy problemu Dubinina-poszukiwania maksimum iloczynu promieni wpisanych kół w niezachodzące na siebie obszary zawierające punkty okręgu jednostkowego i potęgę promienia wpisanego kola w obszar zawierający początek układu współrzędnych. Problem został sformułowany w 1994r. w pracy Dubinina, a następnie powtórzony w monografii tegoż autora z roku 2014. Problem nie jest rozwiązany w ogólnym przypadku. W obecnej pracy problem w postaci dotyczącej bardziej ogólnego układu punktów jest uzyskany dla pewnych konkretnych wartości n oraz y.
https://doi.org/10.26485/0459-6854/2018/68.3/6  The paper is devoted to one extremal problem in geometric function theory of complex variables associated with estimates of functionals defined on the systems of non-overlapping domains. We consider Dubinin’s problem of the maximum of product of inner radii of n non-overlapping domains containing points of the unit circle and the power of the inner radius of a domain containing the origin. The problem was formulated in 1994 in the work of Dubinin and then repeated in his monograph in 2014. Currently it is not solved in general. In this paper we generalized it to the case of the more general system of points and obtained a solution of this problem for some concrete values of n and y.
Źródło:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2018, 68, 3
1895-7838
2450-9329
Pojawia się w:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rapid NEGF-based calculation of ballistic current in ultra-short DG MOSFETs for circuit simulation
Autorzy:
Hosenfeld, F.
Horst, F..
Graef, M.
Farokhnejad, A.
Kloes, A.
Iniguez, B.
Lime, F.
Powiązania:
https://bibliotekanauki.pl/articles/397995.pdf
Data publikacji:
2016
Wydawca:
Politechnika Łódzka. Wydział Mikroelektroniki i Informatyki
Tematy:
ultra-short Double-Gate MOSFET
nonequilibrium Green's function
NEGF
ballistic transport
source-to-drain tunneling
ultra-thin body
UTB
compact model
multi-scale simulation
nierównowagowe funkcje Greena
transport balistyczny
tunelowanie źródło-dren
model kompaktowy
symulacja wieloskalowa
Opis:
Shrinking gate length in conventional MOSFETs leads to increasing short channel effects like source-to-drain (SD) tunneling. Compact modeling designers are challenged to model these quantum mechanical effects. The complexity lies in the set-up between time efficiency, physical model relation and analytical equations. Multi-scale simulation bridges the gap between compact models, its fast and efficient calculation of the device terminal voltages, and numerical device models which consider the effects of nanoscale devices. These numerical models iterate between Poisson- and Schroedinger equation which significantly slows down the simulation performance. The physicsbased consideration of quantum effects like the SD tunneling makes the non-equilibrium Green’s function (NEGF) to a stateof-the-art method for the simulation of devices in the sub 10 nm region. This work introduces a semi-analytical NEGF model for ultra-short DG MOSFETs. Applying the closed-form potential solution of a classical compact model, the model turns the NEGF from an iterative numerical solution into a straightforward calculation. The applied mathematical approximations speed up the calculation time of the 1D NEGF. The model results for the ballistic channel current in DG-MOSFETs are compared with numerical NanoMOS TCAD [1] simulation data. Shown is the accurate potential calculation as well as the good agreement of the current characteristic for temperatures down to 75 K for channel lengths from 6 nm to 20 nm and channel thickness from 1.5 nm to 3 nm.
Źródło:
International Journal of Microelectronics and Computer Science; 2016, 7, 2; 65-72
2080-8755
2353-9607
Pojawia się w:
International Journal of Microelectronics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Boundary behavior of subharmonic functions in nontangential accessible domains
Autorzy:
Zhao, Shiying
Powiązania:
https://bibliotekanauki.pl/articles/1291433.pdf
Data publikacji:
1994
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
subharmonic function
Green potential
boundary limit
NTA domain
Opis:
The following results concerning boundary behavior of subharmonic functions in the unit ball of $ℝ^n$ are generalized to nontangential accessible domains in the sense of Jerison and Kenig [7]: (i) The classical theorem of Littlewood on the radial limits. (ii) Ziomek's theorem on the $L^p$-nontangential limits. (iii) The localized version of the above two results and nontangential limits of Green potentials under a certain nontangential condition.
Źródło:
Studia Mathematica; 1994, 108, 1; 25-48
0039-3223
Pojawia się w:
Studia Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The problem of external decomposition of a complex plane with three poles
Problem ekstremalnego rozkładu płaszczyzny zespolonej z dowolnymi biegunami
Autorzy:
Bakhtin, Aleksandr
Vyhivska, Liudmyla
Powiązania:
https://bibliotekanauki.pl/articles/1837649.pdf
Data publikacji:
2021-08-12
Wydawca:
Łódzkie Towarzystwo Naukowe
Tematy:
inner radius of domain
non-overlapping domains
radial system of points
separating transformation
quadratic differential
Green’s function
wewnętrzny promień obszaru
rozłączne obszary
promieniowy system punktów
transformacja rozdzielająca
różniczka kwadratowa
funkcja Greena
Opis:
Although much research (f. e. [1], [3], [5], [7–15]) has been devoted to the extremal problems of a geometric function theory associated with estimates of functionals defined on systems of non-overlapping domains, however, in the general case the problems remain unsolved. The paper describes the problem of finding the maximum of a functional. This problem is to find a maximum of the product of inner radii of mutually non-overlapping symmetric domains with respect to a unit circle and the inner radius in some positive certain degree of the domain with respect to zero and description of extreme configurations. The topic of the paper is devoted to the study of the problem of the classical direction of the geometric theory of complex variable functions, namely, the extremal problems for non-overlapping domains
Chociaż wiele badań (zob. [1], [3], [5], [7–15]) zostało poświęconych problemom ekstremalnym geometrycznej teorii funkcji, związanych z oszacowaniem funkcjonałów zdefiniowanych na układach rozłącznych obszarów, to jednak w ogólnym przypadku problemy te pozostają nadal otwarte. Praca opisuje problem znalezienia maksimum pewnego funkcjonału. Ten problem, to znalezienie maksimum iloczynu wewnętrznych promieni wzajemnie rozłącznych symetrycznych obszarów (względem okręgu jednostkowego) i wewnętrznego promienia w pewnej dodatniej potędze w obszarze względem zera oraz opis tych ekstremalnych konfiguracji. Tematem pracy jest badanie problemu z klasycznych zagadnień geometrycznej teorii funkcji, a mianowicie problemów ekstremalnych w wzajemnie rozłącznych obszarach
Źródło:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations; 2020, 70, 1; 145-152
1895-7838
2450-9329
Pojawia się w:
Bulletin de la Société des Sciences et des Lettres de Łódź, Série: Recherches sur les déformations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A general boundary value problem and its Weyl function
Autorzy:
Ryzhov, V.
Powiązania:
https://bibliotekanauki.pl/articles/255861.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
abstract boundary value problem
symmetric operators
Green formula
Weyl function
Opis:
We study the abstract boundary value problem defined in terms of the Green identity and introduce the concept of Weyl operator function M(·) that agrees with other definitions found in the current literature. In typical cases of problems arising from the multidimensional partial equations of mathematical physics the function M(·) takes values in the set of unbounded densely defined operators acting on the auxiliary boundary space. Exact formulae are obtained and essential properties of M(·) are studied. In particular, we consider boundary problems defined by various boundary conditions and justify the well known procedure that reduces such problems to the "equation on the boundary" involving the Weyl function, prove an analogue of the Borg-Levinson theorem, and link our results to the classical theory of extensions of symmetric operators.
Źródło:
Opuscula Mathematica; 2007, 27, 2; 305-331
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł

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