Number of found documents: 10791
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Nanopatterning of Silicon Nitride Membranes
Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
2017 - English
Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The principle of silicon nitride membranes preparation is based on the wet anisotropic etching of the bottom side of the silicon wafer with crystallographic orientation (100). While the basic procedure for the preparation of such membranes is well known, the nano patterning of thin membranes presents quite important challenges. This is partially due to the mechanical stress which is typically presented within such membranes. The resolution requirements of the\nmembrane patterning have gradually increased. Advanced lithographic techniques and etching procedures had to be developed. This paper summarizes theoretical aspects, technological issues and achieved results. The application potential of silicon nitride membranes as a base for multifunctional micro system (MMS) is also\ndiscussed. Keywords: e-beam writer; silicon nitride membranes; nano patterning; anisotropic etching Available at various institutes of the ASCR
Nanopatterning of Silicon Nitride Membranes

Membranes are typically created by a thin silicon nitride (SIN) layer deposited on a silicon wafer. Both, top and bottom side of the wafer is covered by a thin layer of the silicon nitride. The ...

Matějka, Milan; Krátký, Stanislav; Řiháček, Tomáš; Kolařík, Vladimír; Chlumská, Jana; Urbánek, Michal
Ústav přístrojové techniky, 2017

Formování kapek v systému dvou nemísitelných kapalin
Kysela, Bohuš; Konfršt, Jiří; Chára, Zdeněk; Šulc, R.; Jašíková, D.
2017 - Czech
Velikost kapek při míchání dvou vzájemně nemísitelných kapalin závisí především na působení vnějších sil. Smyková napětí působící na částici v závislosti na fyzikálních parametrech (povrchové napětí, hustota, viskozita) ovlivňují konečnou distribuci velikostí tvořených kapek. V první fázi jsme se pokusili modelovat dvě reálné nemísitelné kapaliny voda-silikonový olej, které jsou dány svými vlastnostmi. A to na jednoduchém případě výtoku z kapiláry, kde jsme se snažili ověřit, zda a jak moc přesně lze modelovat chování tohoto systému s různými odchylkami fyzikálních parametrů. Dále jsme se snažili určit rovnovážné a mezní stavy v závislosti na zadaných fyzikálních vlastnostech. Keywords: VOF; liquid; multiphase Available at various institutes of the ASCR
Formování kapek v systému dvou nemísitelných kapalin

Velikost kapek při míchání dvou vzájemně nemísitelných kapalin závisí především na působení vnějších sil. Smyková napětí působící na částici v závislosti na fyzikálních parametrech (povrchové napětí, ...

Kysela, Bohuš; Konfršt, Jiří; Chára, Zdeněk; Šulc, R.; Jašíková, D.
Ústav pro hydrodynamiku, 2017

An adaptive recursive multilevel approximate inverse preconditioning: Computation of the Schur complement
Kopal, Jiří; Rozložník, Miroslav; Tůma, Miroslav
2017 - English
Available in digital repository of the ASCR
An adaptive recursive multilevel approximate inverse preconditioning: Computation of the Schur complement

Kopal, Jiří; Rozložník, Miroslav; Tůma, Miroslav
Ústav informatiky, 2017

Simulace zbytkových optických vad objektivu Merz 124/1477
Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan
2017 - Czech
Tento objektiv byl na Ústavu fyziky plazmatu,v.v.i., Centru Toptec v Turnově restaurován. Během tohoto procesu jsme získali možnost objektiv na optické lavici přeměřit a vyčíslit jeho zbytkové optické vady. Objektiv byl vyroben kolem roku 1860-1870. This objective lens was renoved in the Institute of Plasma Physics, v.v.i. Center Toptec in Turnov. During the process we got a possibility to measure the objective lens on the optical bench and to evaluate its residual optical aberrations. The objective lens was manufactured in 1860-1870 years Keywords: Achromatic dublet; spherochromatic aberration; coma; dispersion curve of glass; B-F chromatic correction Available at various institutes of the ASCR
Simulace zbytkových optických vad objektivu Merz 124/1477

Tento objektiv byl na Ústavu fyziky plazmatu,v.v.i., Centru Toptec v Turnově restaurován. Během tohoto procesu jsme získali možnost objektiv na optické lavici přeměřit a vyčíslit jeho zbytkové optické ...

Rail, Zdeněk; Melich, Zbyněk; Šrajer, Bohdan
Ústav fyziky plazmatu, 2017

Optické parametry význačných refraktorů
Rail, Zdeněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
2017 - Czech
V tomto referátu publikujeme optické parametry několika historických dalekohledů, které jsme v literatuře a na webových stránkách získali. Data byla vložena do optického programu ZEMAX, v němž byly vyčísleny jejich zbytkové vady. In this paper we publish the optical parameters of several historic telescopes, which we have found in scientific literature or web pages. Data were inputed into the optical program ZEMAX, which evaluated their residual aberrations. Keywords: Achromatic objective lens; spherochromatic aberration; coma; residual chromatic aberration; Index of refraction; dispersion curve of glass Available at various institutes of the ASCR
Optické parametry význačných refraktorů

V tomto referátu publikujeme optické parametry několika historických dalekohledů, které jsme v literatuře a na webových stránkách získali. Data byla vložena do optického programu ZEMAX, v němž byly ...

Rail, Zdeněk; Jareš, Daniel; Pintr, Pavel; Vápenka, David
Ústav fyziky plazmatu, 2017

Historie observatoře Milešovka
Zacharov, Petr, jr.
2017 - Czech
Horskou stanicí, tj. stanicí s nadmořskou výškou nad 500 m, s nejdelší souvislou řadou měření na našem území\nje meteorologická stanice na hoře Milešovka. Stanice zahájila svou činnost 1. ledna 1905 a délkou svého měření\npatří mezi nejdéle sloužící horské stanice nejen u nás, ale i na světě. Unikátem stanice Milešovka je její umístění\nna vrcholu kuželovité hory ve výšce 837 m n. m. Tato jedinečná poloha je předpokladem toho, že probíhající mě-\nření mají podobný charakter jako měření v okolní atmosféře Keywords: meteorological observatory; Milešovka; meteorological measurements Available at various institutes of the ASCR
Historie observatoře Milešovka

Horskou stanicí, tj. stanicí s nadmořskou výškou nad 500 m, s nejdelší souvislou řadou měření na našem území\nje meteorologická stanice na hoře Milešovka. Stanice zahájila svou činnost 1. ledna 1905 a ...

Zacharov, Petr, jr.
Ústav fyziky atmosféry, 2017

Deformation behaviour of gellan gum based artificial bone structures under simulated physiological conditions
Krčmářová, N.; Šleichrt, J.; Fíla, Tomáš; Koudelka_ml., Petr; Kytýř, Daniel
2017 - English
The paper deals with investigation of deformation behaviour of gellan gum (GG) based\nstructures prepared for regenerative medicine purposes. Investigated material was synthesized as porous spongy-like scaffold reinforced by bioactive glass (BAG) nano-particles in different concentrations. Deformation behavior was obtained employing custom designed experimental setup. This device equipped with bioreactor chamber allows to test the delivered samples under simulated physiological conditions with controlled flow and temperature. Cylindrical samples were subjected to uniaxial quasi-static loading in tension and compression. Material properties of plain scaffold buffered by 50 wt% and 70 wt% BAG were derived from a set of tensile and compression tests. The results are represented in form of stress-strain curves calculated from the acquired force and displacement data. Keywords: gellan gum scaffold; reinforcement; uni-axial loading; simulated physiological conditions Available at various institutes of the ASCR
Deformation behaviour of gellan gum based artificial bone structures under simulated physiological conditions

The paper deals with investigation of deformation behaviour of gellan gum (GG) based\nstructures prepared for regenerative medicine purposes. Investigated material was synthesized as porous ...

Krčmářová, N.; Šleichrt, J.; Fíla, Tomáš; Koudelka_ml., Petr; Kytýř, Daniel
Ústav teoretické a aplikované mechaniky, 2017

Non-holonomic planar and spatial model of a ball-type tuned mass damping device
Náprstek, Jiří; Fischer, Cyril
2017 - English
The area of tuned mass dampers is a wide field of inspiration for theoretical studies in non-linear dynamics and dynamic stability. The studies attempt to estimate behaviour of diverse damping devices and their reliability. The current paper deals with the response of a heavy ball rolling inside a spherical cavity under horizontal kinematic excitation. The non-linear system consists of six degrees of freedom with three non-holonomic constraints. The contact between the ball and the cavity surface is supposed to be perfect without any sliding. The mathematical model using the Appell-Gibbs function of acceleration energy is developed and discussed. Comparison with previous planar (SDOF) model which is based on the Lagrangian procedure is given. The system has an auto-parametric character and therefore semi-trivial solutions and their dynamic stability can be analysed. The most important post-critical regimes are outlined and qualitatively evaluated in resonance domain. Numerical experiments were performed when excitation frequency is slowly swept up and down to identify different modes of response. Some applications in civil engineering as a tuned mass damper, which can be used on slender structures, are mentioned. The proposed device is compared with a conventional pendulum damper. Strengths and weaknesses of both absorbers types\nare discussed. Keywords: tuned mass damper; moving ball; Appell-Gibbs formulation Available at various institutes of the ASCR
Non-holonomic planar and spatial model of a ball-type tuned mass damping device

The area of tuned mass dampers is a wide field of inspiration for theoretical studies in non-linear dynamics and dynamic stability. The studies attempt to estimate behaviour of diverse damping devices ...

Náprstek, Jiří; Fischer, Cyril
Ústav teoretické a aplikované mechaniky, 2017

Some experimentally determined properties of a profile in case of self-excited oscillations in subsonic flow
Vlček, Václav; Zolotarev, Igor; Kozánek, Jan; Šidlof, Petr; Štěpán, M.
2017 - English
In the wind tunnel of the Institute of Thermomechanics of the AS CR,v .v. i., experiments were realized with the profile NACA0015 in the presence of the self-excited oscillation. The oscillation of the profile with pitch and plunge degrees of freedom was excited by the subsonic air flow. The plunge support had the same elasticity for all experiments, the pitch support had seven different values of elasticity. Within experiments different types of self-excited vibration (flutter, stall flutter, deep stall flutter) were realized. Range of Mach numbers were M=0.08–0.45, when the chord length is used as the characteristic dimension of the profile. The frequency and amplitude characteristics of the oscillating profile were experimentally determined.\n Keywords: airfoil; aeroelasciticy; dynamic stall; stall flutter; limit cycle oscillations; self -excited vibrations Available at various institutes of the ASCR
Some experimentally determined properties of a profile in case of self-excited oscillations in subsonic flow

In the wind tunnel of the Institute of Thermomechanics of the AS CR,v .v. i., experiments were realized with the profile NACA0015 in the presence of the self-excited oscillation. The oscillation of ...

Vlček, Václav; Zolotarev, Igor; Kozánek, Jan; Šidlof, Petr; Štěpán, M.
Ústav termomechaniky, 2017

Aspects of energy storage systems focusing on flywheel technologies
Zapoměl, Jaroslav; Kozánek, Jan
2017 - English
The energy storage devices are used to reduce variation of the power transmitted in complex technological systems. The individual technologies are based on different physical principles and are applicable in different industrial fields. This paper focuses on aspects of the flywheel storage devices that have a direct impact on their design, technological parametres, and extent of their application. Keywords: energy storage systems; flywheel technology; ultra-low friction bearings Available at various institutes of the ASCR
Aspects of energy storage systems focusing on flywheel technologies

The energy storage devices are used to reduce variation of the power transmitted in complex technological systems. The individual technologies are based on different physical principles and are ...

Zapoměl, Jaroslav; Kozánek, Jan
Ústav termomechaniky, 2017

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