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Wyszukujesz frazę "diffusion process" wg kryterium: Temat


Tytuł:
Strangely sweeping one-dimensional diffusion
Autorzy:
Rudnicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1311888.pdf
Data publikacji:
1993
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
diffusion process
parabolic equation
Opis:
Let X(t) be a diffusion process satisfying the stochastic differential equation dX(t) = a(X(t))dW(t) + b(X(t))dt. We analyse the asymptotic behaviour of p(t) = Prob{X(t) ≥ 0} as t → ∞ and construct an equation such that $lim sup_{t→∞} t^{-1} ∫_0^t p(s) ds = 1$ and $lim inf_{t→∞}t^{-1} ∫_0^t p(s) ds = 0$.
Źródło:
Annales Polonici Mathematici; 1993, 58, 1; 37-45
0066-2216
Pojawia się w:
Annales Polonici Mathematici
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Echoes and glimpses of a distant drum
Autorzy:
Turner, John Wm.
Powiązania:
https://bibliotekanauki.pl/articles/1397342.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Kac drum problem
inverse methods
diffusion process
Opis:
To what extent does the spectrum of the Laplacian operator on a domain D with prescribed boundary conditions determine its shape? This paper first retraces the history of this problem, then Kac’s approach in terms of a diffusion process with absorbing boundary conditions. It is shown how the restriction to a polygonal boundary for D in this method, which required taking the limit of an infinite number of sides to obtain a smooth one, can be avoided by using the Duhamel method.
Źródło:
Opuscula Mathematica; 2020, 40, 6; 737-750
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Temperature of the Beginning of Alloy Layer Forming Process on the Steel Cast
Autorzy:
Szajnar, J.
Walasek, A.
Baron, C.
Powiązania:
https://bibliotekanauki.pl/articles/381506.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ferrochromium
diffusion process
composite premould
żelazochrom
proces dyfuzyjny
wytłaczanie
Opis:
In this work the results of experiment connected with the problem of formation surface layers on the steel castings. There was an attempt to determine two factors: temperature (premould be higher up 1300°C) and time (heating composite premould). The purpose of the argument was prove of creation surface composit layer in the consequence of heat composite premould (to above temperature of 1300°C). The purpose of conducted research was tests control parameters (have an influence on diffusion process).
Źródło:
Archives of Foundry Engineering; 2013, 13, 1 spec.; 185-188
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Markov operators: applications to diffusion processes and population dynamics
Autorzy:
Rudnicki, Ryszard
Powiązania:
https://bibliotekanauki.pl/articles/1208219.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
Markov operator
asymptotic stability
diffusion process
partial differential equation
Opis:
This note contains a survey of recent results concerning asymptotic properties of Markov operators and semigroups. Some biological and physical applications are given.
Źródło:
Applicationes Mathematicae; 2000, 27, 1; 67-79
1233-7234
Pojawia się w:
Applicationes Mathematicae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Probabilistic solution to a two-dimensional LQG homing problem
Autorzy:
Makasu, C.
Lefebvre, M.
Powiązania:
https://bibliotekanauki.pl/articles/206279.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optimal control
dynamic programming
Whittle's theorem
diffusion process
hitting time
Opis:
Let xt be an arbitrary one-dimensional diffusion process and yt be a one-dimensional controlled diffusion process starting from y0 = y ∈ (a, b). The process is controlled until yt crosses either y = a or y = b for the first time. Our aim is to find the control ut that minimizes an expected cost functional with both quadratic control and boundary crossing costs. An explicit form for the optimal control is obtained under certain conditions.
Źródło:
Control and Cybernetics; 2012, 41, 1; 5-12
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pre-Sintering on the Diffusion Treatment of HRE for Coercivity Enhancement of a NdFeB Sintered Magnet
Autorzy:
Lee, M. W.
Lee, J. K.
Jang, T. S.
Powiązania:
https://bibliotekanauki.pl/articles/355250.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grain boundary diffusion process
GBDP
NdFeB magnet
coercivity
pre-sintering
Opis:
We investigated the effect of pre-sintering process on the penetration behavior of Dy in a NdFeB sintered magnet which was grain boundary diffusion treated with Cu/Al mixed Dy source. The pre-sintering of a magnet was performed at 900°C in vacuum and then the pre-sintered body was dipped in the solutions of DyH2, DyH2 + Cu, and DyH2 + Al, respectively. The dipped pre-sintered body were then fully sintered 4 hours at 1060°C followed by a subsequent annealing. The pre-sintering apparently improved the diffusivity of Dy atoms. The penetration of Dy into the magnet extended almost to 2,000 μm from the surface, about four times deeper than that of the normally sintered and diffusion treated one, when the DyH2 + Al solution was used as a Dy source. However, the resulting increase of coercivity was about 4 kOe, somewhat lower than that of the normally treated one, mostly due to excessive oxide formation that hindered to make a continuous Nd-rich grain boundary phase and a core-shell type structure.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 597-601
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One-dimensional diffusions in bounded domains with a possible jump-like exit from a sticky boundary
Autorzy:
Kopytko, B.
Shevchuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/122536.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
diffusion process
parabolic potential
conjugation problem
proces dyfuzji
potencjał paraboliczny
Opis:
Using analytical methods we obtain the integral representation of a two-parameter Feller semigroup on a closed interval [r1, r2] corresponding to such a diffusion phenomenon that sticking, partial reflection, absorption and jump phenomena occur at the endpoints r1, r2 and at some interior point r ∈ (r1,r2).
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 3; 101-114
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Some examples of solutions to an inverse problem for the first-passage place of a jump-diffusion process
Autorzy:
Abundo, Mario
Powiązania:
https://bibliotekanauki.pl/articles/2183487.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
jump-diffusion process
first-passage place
inverse first-passage place problem
Opis:
We report some additional examples of explicit solu- tions to an inverse first-passage place problem for one-dimensional diffusions with jumps, introduced in a previous paper. If X(t) is a one-dimensional diffusion with jumps, starting from a random position η 2 [a, b], let be τa,b the time at which X(t) first exits the interval (a, b), and πa = P(X(τa,b) ≤ a) the probability of exit from the left of (a, b). Given a probability q 2 (0, 1), the problem consists in finding the density g of η (if it exists) such that πa = q; it can be seen as a problem of optimization.
Źródło:
Control and Cybernetics; 2022, 51, 1; 31--42
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mixer with microchannels in LTCC technology
Autorzy:
Kamiński, S.
Rebenklau, L.
Uhlemann, J.
Wolter, K.-J.
Powiązania:
https://bibliotekanauki.pl/articles/378427.pdf
Data publikacji:
2006
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Elektronowej
Tematy:
technologia LTCC
mikromontaż
etanol
dyfuzja wody
LTCC technology
micromixer
water diffusion process
ethanol
Opis:
LTCC technology gives the possibility to form spatial structures and can be used to produce components, applied in analytical fluidic systems. This paper will discuss related construction of Y-shaped mixer with microchannels, including cutting process in two lamination layers of LTCC using CO₂ laser. The sample was fabricated by combination of LTCC structure with PMMA covers (polymethylmethacrylate). Mixer was designed for the fluid flow rate to 20 μl/min. The sample was examined for the two fluids: water and ethanol.
Źródło:
Electron Technology : Internet Journal; 2005-2006, 37/38, 9; 1-3
1897-2381
Pojawia się w:
Electron Technology : Internet Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder
Autorzy:
Lee, M.-W.
Bae, K.-H.
Lee, S.-R.
Kim, H.-J.
Jang, T.-S.
Powiązania:
https://bibliotekanauki.pl/articles/353351.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B sintered magnets
grain boundary diffusion process
low melting point element
DyCo alloy-powder diffusion
Opis:
We investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1st post annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2 Fe14 B and grain boundary phases covering Nd2 Fe14 B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3 phase.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1263-1266
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of polynomial tensor interpolation for technical tests
Autorzy:
Ciekot, Anita
Biernat, Grzegorz
Frączek, Tadeusz
Powiązania:
https://bibliotekanauki.pl/articles/1839850.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
polynomial tensor interpolation
Kronecker product
diffusion process
wielomianowa interpolacja tensora
produkt Kroneckera
proces dyfuzji
Opis:
The main aim of this paper is a new formula of tensor interpolation by the polynomial of two variables. The formulas for interpolating polynomial coefficients are obtained using the Kronecker tensor product of matrices. The mathematical model for the diffusion process is presented. This paper is focused on determining the optimal parameters for this process by polynomial tensor interpolation of the obtained research results.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2021, 20, 1; 17-24
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modeling of random diffusion flows in two-phase multilayered stochastically nonhomogeneous bodies
Autorzy:
Chaplya, Y.
Chernukha, O.
Davydok, A.
Powiązania:
https://bibliotekanauki.pl/articles/1938615.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska
Tematy:
diffusion process
mass flow
random structure
Neumann series
averaging over the ensemble of phase configurations
Opis:
An approach for studying stochastical diffusion flows of admixture particles in bodies of multiphase randomly nonhomogeneous structures is proposed, according to which initialboundary value problems of diffusion are formulated for flow functions and methods of solution construction are adapted for the formulated problems. By this approach the admixture diffusion flow is investigated in a two-phase multilayered strip for the uniform distribution of phases under conditions of constant flow on the upper surface and zero concentration of admixture on the lower surface. An integro-differential equation equivalent to the original initial-boundary value problem is constructed. Its solution is found in terms of the Neumann series. Calculation formulae are obtained for the diffusion flow averaged over the ensemble of phase configurations under both zero and constant nonzero initial concentrations. Software is developed, a dependence of averaged diffusion flows on the medium characteristics is studied and general regularities of this process are established.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 3; 297-320
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
One-dimensional diffusion processes in half-bounded domains with reflection and a possible jump-like exit from a moving boundary
Autorzy:
Kopytko, B.
Shevchuk, R.
Powiązania:
https://bibliotekanauki.pl/articles/122425.pdf
Data publikacji:
2016
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
diffusion process
parabolic potential
Feller-Wentzell boundary condition
proces dyfuzji
potencjał paraboliczny
warunek brzegowy Feller-Wentzell
Opis:
By the method of the classical potential theory, we construct the two-parameter Feller semigroup of operators associated with such a diffusion phenomenon on a half-line with a moving boundary where either a reflection or jump phenomenon occurs at a boundary point.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2016, 15, 4; 71-82
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Structural Stability of the Fe36 Co36 Si19 B5 Nb4 Bulk Amorphous Alloy
Stabilność struktury masywnego stopu amorficznego Fe36 Co36 Si19 B5 Nb4
Autorzy:
Nabiałek, M.
Pietrusiewicz, P.
Szota, M.
Dobrzańska-Danikiewicz, A.
Lesz, S.
Dośpiał, M.
Błoch, K
Oźga, K.
Powiązania:
https://bibliotekanauki.pl/articles/354967.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bulk amorphous alloys
surface
diffusion process
microstructure
fracture surface morphology
masywny stop amorficzny
powierzchnia
proces dyfuzji
mikrostruktura
Opis:
In this paper, the results of the investigation into the fractured surface microstructure of the amorphous samples of Fe36 Co36 Si19 B5 Nb4 in the shape of rods of diameters: 1 mm, 2 mm and 3 mm in the as-cast state are presented. The samples were prepared by injection of molten alloy into cooled copper dies. The process of diffusion in the investigated material has a different speed depending on the temperature gradient within the volume of the rod. The atomic diffusion leads to the creation of different zones within the rod fracture: the zone in contact with the copper die, the intermediate fracture zone, and the zone in the vicinity of the rod core; the three zones have been found to exhibit different amorphous structures.
W pracy przedstawiono wyniki badań mikrostruktury na powierzchni przełomów próbek Fe36 Co36 Si19 B5 Nb4 amorficznych w postaci prętów o średnicy 1 mm. 2 mm i 3 mm. w stanie po zestaleniu. Pręty wytworzono metodą wtłaczania ciekłego stopu do miedzianej, chłodzonej cieczą formy. Proces dyfuzji atomów w badanym materiale charakteryzuje się inną dynamiką w zależności od gradientu temperatury w objętości pręta. Wyróżnia się trzy wyraźnie widoczne strefy: od kontaktu z miedzianą formą, strefę przejściową oraz strefę opisującą rdzeń pręta. Każdą z wyróżnionych stref charakteryzują różne konfiguracje atomów w zakresie stanu amorficznego. Na podstawie badań stwierdzono, że w masywnych materiałach amorficznych występuje fluktuacja składu oraz gęstości w zależności od szybkości chłodzenia.
Źródło:
Archives of Metallurgy and Materials; 2014, 59, 1; 259-262
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of diffusion flows in two-phase multilayered stochastically nonhomogeneous bodies with non-uniform distribution of inclusions
Autorzy:
Chaplya, Y.
Chernukha, O.
Davydok, A.
Powiązania:
https://bibliotekanauki.pl/articles/1938616.pdf
Data publikacji:
2015
Wydawca:
Politechnika Gdańska
Tematy:
diffusion process
mass flow
random structure
Neumann series
averaging over the ensemble of phase configurations
beta distribution
Opis:
Admixture diffusion flows are investigated in two-phase randomly nonhomogeneous multilayered strips with non-uniform distributions of inclusions. Cases where the most probable disposition of layered inclusions is located near the body boundary on which the mass source acts in the neighborhood of another boundary and in the middle of the body are considered. The initial-boundary value problem is formulated for the function of random mass flow under conditions of a constant flow on the upper surface and zero concentration of the admixture on the lower surface. Calculation formulae are obtained for the diffusion flow averaged over the ensemble of phase configurations in the particular cases of beta-distribution at zero and nonzero initial concentrations. The dependences of the averaged admixture flows on medium characteristics are established. It is shown that if the admixture diffusion coefficient in inclusions is greater than in the matrix, consolidation of inclusions in the middle of the body leads to an increasing diffusion flow. Simulation of the averaged diffusion flows of the admixture in the multilayered strip is performed for different model variants of a probable disposition of phases in the body and their comparative analysis is carried out.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2015, 19, 3; 321-351
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł

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