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1
Content available remote Boundary element modeling of pyroelectric solids with shell inclusions
Sulym H., Pasternak I., Pasternak V.
Mechanics and Mechanical Engineering
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2018
|
Vol. 22, nr 3
727--737
EN
The paper presents general boundary element approach for analysis of thermoelectroelastic (pyroelectric) solids containing shell-like electricity conducting permittive inclusions. The latter are modeled with opened surfaces with certain boundary conditions on their faces. Rigid displacement and rotation, along with constant electric potential of inclusions are accounted for in these boundary conditions. Formulated boundary value problem is reduced to a system of singular boundary integral equations, which is solved numerically by the boundary element method. Special attention is paid to the field singularity at the front line of a shell-like inclusion. Special shape functions are introduced, which account for this square-root singularity and allow accurate determination of field intensity factors. Numerical examples are presented.
2
Content available Boundary element analysis of anisotropic thermomagnetoelectroelastic solids with 3D shell-like inclusions
Pasternak I., Sulym H.
Acta Mechanica et Automatica
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2017
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Vol. 11, no. 4
308--312
EN
The paper presents novel boundary element technique for analysis of anisotropic thermomagnetoelectroelastic solids containing cracks and thin shell-like soft inclusions. Dual boundary integral equations of heat conduction and thermomagnetoelectroelasticity are derived, which do not contain volume integrals in the absence of distributed body heat and extended body forces. Models of 3D soft thermomagnetoelectroelastic thin inclusions are adopted. The issues on the boundary element solution of obtained equations are discussed. The efficient techniques for numerical evaluation of kernels and singular and hypersingular integrals are discussed. Nonlinear polynomial mappings are adopted for smoothing the integrand at the inclusion’s front, which is advantageous for accurate evaluation of field intensity factors. Special shape functions are introduced, which account for a square-root singularity of extended stress and heat flux at the inclusion’s front. Numerical example is presented.
3
Content available Longitudinal shear of a bi-material with frictional sliding contact in the interfacial crack
Sulym H., Pasternak I., Piskozub L., Piskozub Y.
Journal of Theoretical and Applied Mechanics
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2016
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Vol. 54 nr 2
529--539
EN
We construct an analytical solution to the anti-plane problem of an inhomogeneous bi- -material medium with the interfacial crack considering sliding friction. The medium is exposed to an arbitrary normal and shear loading in the longitudinal direction. Using the jump function method, the problem is reduced to a solution to singular integral equations for the jumps of displacements and stresses in the areas with sliding friction. Explicit expressions for displacements, stress intensity factors and energy dissipation are obtained. Critical load values for determination of the onset of slippage are investigated. The effect of friction and loading parameters on the size of the slip zone, stress intensity factors and energy dissipation is numerically analyzed.
4
Content available Boundary integral equations for an anisotropic bimaterial with thermally imperfect interface and internal inhomogeneities
Sulym H., Pasternak I., Tomashivskyy M.
Acta Mechanica et Automatica
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2016
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Vol. 10, no. 1
66--74
EN
This paper studies a thermoelastic anisotropic bimaterial with thermally imperfect interface and internal inhomogeneities. Based on the complex variable calculus and the extended Stroh formalism a new approach is proposed for obtaining the Somigliana type integral formulae and corresponding boundary integral equations for a thermoelastic bimaterial consisting of two half-spaces with different thermal and mechanical properties. The half-spaces are bonded together with mechanically perfect and thermally imperfect interface, which model interfacial adhesive layers present in bimaterial solids. Obtained integral equations are introduced into the modified boundary element method that allows solving arbitrary 2D thermoelacticity problems for anisotropic bimaterial solids with imperfect thin thermo-resistant interfacial layer, which half-spaces contain cracks and thin inclusions. Presented numerical examples show the effect of thermal resistance of the bimaterial interface on the stress intensity factors at thin inhomogeneities.
5
Content available Antiplane deformation of a bimaterial containing an interfacial crack with the account of friction 2. Repeating and cyclic loading
Sulym H., Piskozub L., Piskozub Y., Pasternak I.
Acta Mechanica et Automatica
|
2015
|
Vol. 9, no. 3
178--184
EN
The paper presents the exact solution of the antiplane problem for an inhomogeneous bimaterial with the interface crack exposed to the normal load and cyclic loading by a concentrated force in the longitudinal direction. Using discontinuity function method the problem is reduced to the solution of singular integral equations for the displacement and stress discontinuities at the domains with sliding friction. The paper provides the analysis of the effect of friction and loading parameters on the size of these zones. Hysteretic behaviour of the stress and displacement discontinuities in these domains is observed.
6
Content available Antiplane deformation of a bimaterial containing an interfacial crack with the account of friction. [P.] 1, Single loading
Sulym H., Piskozub L., Piskozub Y., Pasternak I.
Acta Mechanica et Automatica
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2015
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Vol. 9, no. 2
115--121
EN
The paper presents the exact analytic solution to the antiplane problem for a non-homogeneous bimaterial medium containing closed interfacial cracks, which faces can move relatively to each other with dry friction. The medium is subjected to the action of normal and arbitrary single loading in a longitudinal direction. Based on the discontinuity function method the problem is reduced to the solution of the system of singular integral-differential equations for stress and displacement discontinuities at the possible slippage zones. Influence of loading parameters and the effects of friction on the sizes of these zones is analyzed. The stress intensity factors, stress and displacement discontinuities, energy dissipation are determined for several characteristic types of external loading.
7
Content available remote Metody charakteryzacji grafenu wykorzystywanego w sensorowych układach rezystancyjnych
Drewniak S., Pustelny T., Strupiński W., Pasternak I., Opilski Z.
Prace Naukowe Politechniki Śląskiej. Elektryka
|
2014
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z. 2-3
63--72
PL
Zanieczyszczenie środowiska pociąga za sobą konieczność monitoringu wybranych atmosfer gazowych. W niniejszym artykule zostaną przedstawione wyniki charakteryzacji warstwy gazoczułej (grafenu) w rezystancyjnym czujniku cienkowarstwowym, pozwalającym wykrywać niskie zawartości wodoru oraz dwutlenku azotu w atmosferze powietrza syntetycznego. Zostaną przedstawione m.in. obrazy topografii powierzchni oraz widma ramanowskie struktury. Analizowane będą zmiany, jakie zachodzą w strukturze (obserwowane na widmach ramanowskich) pod wpływem jej kontaktu z atmosferą zawierającą 3% wodoru.
EN
The environmental pollution entails the monitoring of selected gas atmospheres. In this paper, the results of characterization the thin film resistance sensor (characterization of grapheme - sensitive layer) will be presented. Such sensor can detect the hydrogen and nitrogen dioxide in the atmosphere of synthetic air at a very low level. There will be presented, among others, the images of topography and raman’s spectras of the structures. There will be analyzed changes which occure in the structure (observed at the Raman’s spectra) due to its contact with the atmosphere containing 3% hydrogen.
8
Content available Doubly periodic cracks in the anisotropic medium with the account of contact of their faces
Maksymovych O., Pasternak I., Sulym H., Kutsyk S.
Acta Mechanica et Automatica
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2014
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Vol. 8, no. 3
160--164
EN
The paper presents complex variable integral formulae and singular boundary integral equations for doubly periodic cracks in anisotropic elastic medium. It utilizes the numerical solution procedure, which accounts for the contact of crack faces and produce accurate results for SIF evaluation. It is shown that the account of contact effects significantly influence the SIF of doubly periodic curvilinear cracks both for isotropic and anisotropic materials.
9
Content available Comparison of CVD graphene grown on copper foil and PVD copper
Pasternak I., Grodecki K., Piątkowska A., Ciuk T., Caban P., Strupiński W.
Materiały Elektroniczne
|
2013
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T. 41, nr 2
26--33
EN
Graphene synthesis by the CVD method performed on the surface of copper is one of the most promising techniques for producing graphene for low cost and large scale applications. Currently, the most commonly used Cu substrate for graphene growth is foil, however, there is still a need to find new substrates and improve the quality of graphene layers. Sputtered Cu films on insulating substrates are considered as an alternative. Here we show the properties of graphene grown by the CVD method on thin copper foil and PVD copper films on Si/SiO2 substrates. We compare data on the properties of graphene films transferred from different copper substrates onto SiO2/Si substrates. We note that graphene grown on sputtered Cu films creates a multilayer form on the boundaries which can be identified on micro-Raman maps and in SEM images.
PL
Wytwarzanie grafenu metodą CVD na podłożach miedzianych jest jedną z najbardziej perspektywicznych metod otrzymywania grafenu ze względu na niski koszt podłoża oraz szerokie możliwości zastosowania w przemyśle. Obecnie najczęściej stosowanym do wzrostu grafenu podłożem miedzianym jest folia, jednakże ciągle istnieje potrzeba znalezienia nowego podłoża tak by poprawić jakość warstw grafenu. Jako alternatywę rozważa się cienkie warstwy miedzi wytwarzane metodami PVD osadzane na nieprzewodzącym podłożu. W niniejszym artykule przedstawiamy własności grafenu wytwarzanego metodą CVD na cienkiej folii miedzianej oraz na warstwach miedzi osadzonych na Si/SiO2. Porównujemy także wyniki otrzymane dla przeniesionych warstw grafenu z obu rodzajów próbek.
10
Content available The sensibility of resistance sensor structures with graphene to the action of selected gaseous media
Pustelny T., Setkiewicz M., Drewniak S., Maciak E., Stolarczyk A., Urbańczyk M., Procek M., Gut K., Opilski Z., Pasternak I., Strupinski W.
Bulletin of the Polish Academy of Sciences. Technical Sciences
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2013
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Vol. 61, nr 2
293--300
EN
The paper presents resistance sensor structures with a graphene sensing layer. The structures were tested concerning their sensitivity to the affects of hydrogen, nitrogen dioxide and steam in an atmosphere of a synthetic air. Investigations have proved that resistance structures with a graphene layer are sensitive to the presence of the tested gases. The resistance of the structures amounted to about 10Ω, whereas changes in the resistances affected by the external gaseous medium were contained within the range of a several mΩ. The investigations confirmed that the resistance structures with graphene exposed to the affect of hydrogen in atmosphere of synthetic air change their resistances practically at once (within the order of only a few seconds). This indicates that such structures might be practically applied in sensors of hydrogen ensuring a short time of response.
11
Content available Doubly Periodic Sets of Thin Branched Inclusions in the Elastic Medium: Stress Concentration and Effective Properties
Sulym H., Pasternak I., Kutsyk S., Grodzki W.
Acta Mechanica et Automatica
|
2013
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Vol. 7, no. 1
48-52
EN
This paper considers the doubly periodic problem of elasticity for anisotropic solids containing regular sets of thin branched inclusions. A coupling principle for continua of different dimension is utilized for modeling of thin inhomogeneities and the boundary element technique is adopted for numerical solution of the problem. The branches of the inclusion can interact both inside the representative volume element and at the interface of neighbor representative elements. A particular example of the elastic medium reinforced by a doubly periodic set of I-beams is considered. Stress intensity and stress concentration inside and outside thin inclusions are determined. The dependence of the effective mechanical properties of the reinforced composite material on the volume fraction of the filament and its rigidity is obtained.
12
Content available Modelling of stress state of elastic medium containing perfectly and imperfectly bonded thin inclusions and overlays
Sulym H., Pasternak I.
Mechanics and Control
|
2011
|
Vol. 30, no. 3
176-181
EN
This study considers modelling of two-dimensional stress state of solids containing thin elastic inclusions. In modeling the coupling principle for continua of different dimension is utilized. Basing on the model of inclusion under the perfect contact three other models of imperfect contact are developed. The simplest one is a model of thin inclusion, which is completely delaminated at certain segments. Two other models take into account a smooth contact between inclusion and a solid, and also a contact with friction. The developed models are easy to introduce into the used boundary element approach. The model of inclusion, completely debonded at one face, is also used in modeling of solids with thin elastic overlays or stringers.
PL
W pracy przy użyciu zasady sprzężenia kontinuów różnowymiarowych rozważane są sposoby matematycznego modelowania zagadnienia płaskiego dla ośrodków sprężystych zawierających cienkie inkluzje. Zasadniczy model matematyczny dla cienkiej inkluzji połączonej w doskonały sposób z tarczą uwzględnia możliwość sprężystego odkształcenia w kierunkach: poprzecznym i wzdłużnym względem osi inkluzji oraz efekty jej zginania. Zostały sprecyzowane trzy szczególne modele niedoskonałego kontaktu inkluzji. Najprostszym z nich jest model cienkiego wtrącenia, które wzdłuż pewnych segmentów jest odseparowane od macierzy. Dwa inne modele uwzględniają gładki kontakt inkluzji z ciałem oraz kontakt z tarciem. Opracowane modele łatwo łączy się ze schematem metody elementów brzegowych. Model cienkiej inkluzji zupełnie odseparowanej wzdłuż jednej strony nadaje się również do badania ośrodków z cienkim wzmocnieniem powierzchniowym (nakładką).
13
Wytwarzanie i charakteryzacja cienkich warstw tlenku hafnu dla zastosowań w technologii MOSFET w węgliku krzemu
Taube A., Korwin-Mikke K., Gutt T., Małachowski T., Pasternak I., Wzorek M., Łaszcz A., Płuska M., Rzodkiewicz W., Piotrowska A., Gierałtowska S., Sochacki M., Mroczyński R., Dynowska E., Szmidt J.
Elektronika : konstrukcje, technologie, zastosowania
|
2011
|
Vol. 52, nr 9
117-120
PL
W pracy przedstawiono wyniki charakteryzacji cienkich warstw tlenku hafnu wytwarzanych metodą ALD. Zbadano wpływ wygrzewania na parametry elektrofizyczne warstw HfO₂ oraz HfO₂/SiO₂ oraz wpływ zastosowania warstwy podkładowej na właściwości elektryczne struktur MIS z warstwa tlenku hafnu osadzoną na węgliku krzemu. Zastosowanie warstwy podkładowej z SiO₂ znacznie poprawiło parametry kondensatorów MIS na węgliku krzemu, zmniejszając prąd upływu oraz gęstość ładunku efektywnego w dielektryku. Zaobserwowano zwiększenie się pola przebicia do wartości 7.2 MV/cm. Wygrzewanie warstw HfO₂/SiO₂ w temperaturze 400°C zwiększyło ich niezawodność oraz zredukowało gęstość stanów powierzchniowych do 4×10¹¹ eV⁻¹ cm⁻². Wygrzewanie warstw HfO₂ w 400°C obniżyło prąd upływu przy jednoczesnym zwiększeniu względnej przenikalności elektrycznej.
EN
This work presents the results of characterization of thin hafnium oxide films fabricated by ALD. Effect of annealing on physical properties on HfO₂ and HfO₂/SiO₂ layers, as well as effect of introduction of pedestal layers on properties of 4H-SiC MIS capacitor was investigated. Introduction of SiO₂, pedestal layer improved properties of 4H-SiC MIS capacilors, causing decreasing of leakage current and effective charge density in the insulator. Electric breakdown field was increased from 4 7 to 7.2 MV/cm. Annealmg of HfO₂/SiO₂ layers m 400°C improved reliability and reduced density of interface traps. Annealing of HfO₂ - layers m 400°C caused decreasing of leakage current and increased of relative permittivity.
14
Trawienia półprzewodników szerokoprzerwowych GaN i SiC
Kruszka R., Korwin-Mikke K., Pasternak I., Wzorek M., Kamińska E., Piotrowska A.
Elektronika : konstrukcje, technologie, zastosowania
|
2011
|
Vol. 52, nr 9
32-36
PL
W pracy przedstawiono wyniki badań procesów kształtowania wzorów w azotku galu i węgliku krzemu przy użyciu techniki fotolitografii optycznej oraz trawienia plazmowego ICP. Do trawienia GaN stosowano plazmy chlorowe BCl₃/Cl₂ lub CI₂/Ar. Natomiast do trawienia SiC użyto plazmy chlorowej BCl₃/Cl₂ oraz plazmy freonowej CF₄. Trawienia GaN i SiC prowadzono przez maski metaliczne (Cr), tlenkowe (SiO₂) oraz złożone (Cr/SiO₂). Porównano szybkości trawienia w różnych rodzajach plazm oraz chropowatość powierzchni przed trawieniem i po procesie trawienia.
EN
This work concerns results of the studies on forming ot the patterns in gallium nitride and silicon carbide using optical photolithography and plasma etching techniques. For GaN etching chlorine plasma BCl₃/Cl₂ or CI₂/Ar were used. SiC has been etched in BCl₃/Cl₂ chlorine and freon CF₄ plasmas. The rate of etching in different types of plasmas and surface roughness before and after etching process were compared.
15
Procesy trawienia suchego ICP w plazmie BCI₃ cienkich warstw HfO₂ wytworzonych techniką reaktywnego rozpylania katodowego
Kruszka R., Gołaszewska K., Taube A., Pasternak I., Korwin-Mikke K., Wzorek M., Kamińska E., Piotrowska A.
Elektronika : konstrukcje, technologie, zastosowania
|
2011
|
Vol. 52, nr 9
91-94
PL
W pracy przedstawiono wyniki trawienia plazmowego ICP warstw HfO₂ wytwarzanych metodą reaktywnego rozpylania katodowego. Na podstawie badań porównawczych procesów trawienia wybrano plazmę BCI₃: F(sub)BCI3 = 30 sccm, P(sub)ICP/P(sub)RIE = 1000 W/100W, p = 10 mTorr, T = 20°C. Określono szybkość trawienia tlenku hafnu wynoszącą v∼80 nm/min, oraz seleklywność trawienia w stosunku do Si i SiC oraz selektywność trawienia HfO₂ do materiału maski tlenkowej (SiO₂) i emulsyjnej.
EN
In this paper we present the results of the ICP etching of the HfO₂ layers deposited by the reactive sputtering After the comparative tests of the process parameters, BCI₃ plasma (f(sub)BCI3 = 30sccm, P(sub)ICP/P(sub)RIE = 1000W/100W, p = 10 mTorr, T = 20 °C) has been chosen. Etching rate of ∼80nm/min has been determined. Etching selectivity HfO₂:Si and HfO₂: SiC as well as selectmty to oxide (SIO₂) and emulsion masks have been measured. No changes in the roughness of HfO₂ layers have been observed.
16
Content available Bending of Orthotropic Plate Containing a Crack Parallel to the Median Plane
Shvabyuk V., Pasternak I., Sulym H.
Acta Mechanica et Automatica
|
2011
|
Vol. 5, no. 4
94-102
EN
This paper considers cylindrical bending of the plate containing a crack parallel to plate's faces. The analytical model of the problem is obtained using the improved theory of plates bending, which considers transverse deformation of the plate. Received analytical results are compared with the numerical data of the boundary element approach, which is modified to suit the considered contact problem. The results of analytical and numerical techniques are in a good agreement both for the isotropic and anisotropic plates.
17
Content available BEM Approach for the Antiplane Shear of Anisotropic Solids Containing Thin Inhomogeneities
Bozhydarnyk V., Pasternak I., Sulym H., Oliyarnik N.
Acta Mechanica et Automatica
|
2011
|
Vol. 5, no. 4
1-16
EN
This paper considers a development of the boundary element approach for studying of the antiplane shear of elastic anisotropic solids containing cracks and thin inclusions. For modeling of thin defects the coupling principle for continua of different dimension is utilized, and the problem is decomposed onto two separate problems. The first is an external one, which considers solid containing lines of displacement and stress discontinuities and is solved using boundary element approach. The second is internal one, which considers deformation of a thin inhomogeneity under the applied load. Compatible solution of external and internal problems gives the solution of the target one. Stroh formalism is utilized to account the anisotropy of a solid and inclusion. Numerical example shows the efficiency and advantages of the proposed approach.
18
Content available remote The unified approach for the analysis of elastic equilibrium of solids containing thin internal and surface heterogeneities
Pasternak I., Sulym H.
Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika
|
2010
|
z. 81 [277]
51-60
EN
This paper develops the unified approach for the analysis of plane elastostatic problems for solids containing thin elastic inclusions or overlays. The approach is based on the previously developed integral equation method for the solution of plane elastostatic problems for solids with perfectly embedded inclusions. In this paper the method is extended to the case of delaminated inclusion and elastic enforcing overlay. Thus, the wide class of problems can be solved basing on the developed technique.
19
Wytwarzanie submikrometrowych wzorów techniką nanostemplowania
Ekielski M., Juchniewicz M., Pasternak I., Piotrowska A.
Elektronika : konstrukcje, technologie, zastosowania
|
2010
|
Vol. 51, nr 9
106-108
PL
Praca prezentuje wyniki dotyczące wytwarzania submikrometrowych wzorów techniką nanostemplowania. Eksperyment przeprowadzono na 3" podłożach krzemowych oraz 5×5 mm podłożach kwarcowych. Zaprezentowano dwa warianty techniki nanostemplowania tj. termiczny i UV oraz omówiono podstawowe parametry charakteryzujące jakość odwzorowania.
EN
We report on submicrometer pattern fabrication using nanoimprint lithography. The experiments were performed on 3" silicon and 5×5 mm quartz substrates. We demonstrate two modes of nanoimprint lithography i.e. thermal and UV, and discuss the parameters determining the quality of pattern replication.
20
Morfologia powierzchni międzyfazowych w wielowarstwowych strukturach periodycznych AlGaAs/GaAs
Barańska A., Kosiel K., Kubacka-Traczyk J., Bugajski M., Pasternak I., Płociński T., Kurzydłowski K.
Elektronika : konstrukcje, technologie, zastosowania
|
2010
|
Vol. 51, nr 10
112-115
PL
Artykuł przedstawia wyniki badań morfologii powierzchni międzyfazowych heterostruktur epitaksjalnych AlGaAs/GaAs. Struktury zostały wykonane metodą epitaksji z wiązek molekularnych (MBE). Charakteryzację struktur przeprowadzono stosując mikroskopię sił atomowych (AFM) oraz wysokorozdzielczą transmisyjną mikroskopię elektronową (HRTEM). Badano warstwy GaAs/GaAs, AlGaAs/GaAs oraz wielowarstwowe struktury periodyczne AlGaAs/GaAs, osadzane na podłożach o orientacji (100).
EN
The paper presents some results of investigation of interfacial morphology in AlGaAs/GaAs epitaxial heterostructures. The structures were grown by molecular beam epitaxy (MBE). Their characterisation was performed by atomie force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). The simple GaAs/GaAs, AlGaAs/GaAs as well as multilayer, periodic AlGaAs/GaAs heterostructures deposited on (100) GaAs substrates were studied.
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