Number of found documents: 1038
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SMV-2017-29: Generátor proudů pro 3D systém prostorových cívek GMP4
Vondra, Vlastimil
2017 - Czech
Vývoj pokročilého experimentálního systému pro 3D nastavení magnetického pole uvnitř systému 3D prostorových cívek dle definovaných požadavků včetně časového programování vývoje velikosti a směru vektoru mg. pole. Systém je vybaven přesným monitorováním skutečné velikosti vektoru mg. pole, který je zapojen ve smyčce zpětné vazby. Development of an advanced experimental system for adjustment of the magnetic field inside the 3D coil system according to defined requirements, including the time programming of the magnitude and direction of the magnetic. field vector. The system is equipped with accurate monitoring of the actual magnitude of mg. field vector that is connected in the feedback loop. Keywords: power generator; magnetic field; measurement of the magnetic field; 3D vector magnetic field Available at various institutes of the ASCR
SMV-2017-29: Generátor proudů pro 3D systém prostorových cívek GMP4

Vývoj pokročilého experimentálního systému pro 3D nastavení magnetického pole uvnitř systému 3D prostorových cívek dle definovaných požadavků včetně časového programování vývoje velikosti a směru ...

Vondra, Vlastimil
Ústav přístrojové techniky, 2017

Effect of thermal radiation on low temperature measurement for various types of temperature sensor installations
Urban, Pavel; Hanzelka, Pavel; Králík, Tomáš; Vlček, Ivan; Srnka, Aleš
2017 - English
We investigated an effect of thermal radiation (300 K) on precision of low temperature measurement of a sample holder (or sample) in an UHV SEM/SPM microscope working at range down to 20 K for various ways of temperature sensor mounting. We designed a special copper casing for installation of Lake Shore\ntemperature sensors (CernoxTM and Si diodes) encapsulated in SD packages. The sensor body is attached direct to the casing using indium solder. The current leads pertaining to the sensor are thermally anchored but electrically insulated from the casing. Quality of sensors installation in the casing was tested for various ways of mounting on a cooled plate. Insufficient thermal anchoring of electrical wires and thermal shielding were imitated. Comparative measurement was also performed with sensors in SD package mounted without\ncasing. The experiments proved that our special design of temperature sensors casing is adequate for intended application of temperature measurement of sample holder in UHV SEM/SPM microscope. In contrary, measurement precision of unprotected sensors was absolutely unsuitable. Keywords: low temperature; temperature sensor; thermal radiation Available at various institutes of the ASCR
Effect of thermal radiation on low temperature measurement for various types of temperature sensor installations

We investigated an effect of thermal radiation (300 K) on precision of low temperature measurement of a sample holder (or sample) in an UHV SEM/SPM microscope working at range down to 20 K for various ...

Urban, Pavel; Hanzelka, Pavel; Králík, Tomáš; Vlček, Ivan; Srnka, Aleš
Ústav přístrojové techniky, 2017

SMV-2017-01: Reliéfní struktury na principu difraktivní optiky
Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Krátký, Stanislav; Chlumská, Jana; Meluzín, Petr; Král, Stanislav
2017 - Czech
Výzkum a vývoj v oblasti fyzikální realizace grafických a optických struktur na principu difraktivní optiky prostředky elektronové litografie v záznamovém materiálu neseném křemíkovou nebo skleněnou deskou. Výzkum zahrnuje analýzu grafického resp. optického motivu, výzkum a aplikaci reliéfních struktur realizujících požadované grafické resp. optické vlastnosti, výzkum a modelování možností fyzikální realizace reliéfních struktur, vypracování a analýzu technologie realizace reliéfní struktury s ohledem na limity současných vědeckých přístrojů, ověření teoretických úvah expozicí vzorku reliéfní struktury. Research and development in the field of physical realization of graphic and optical structures based on the principle of diffractive optics by means of electron beam lithography in a recording material supported by a silicon or glass board. The research covers the analysis of the graphical or optical motive, research and application of relief structures implementing the required graphic and optical properties, research and modeling of the physical possibilities of implementation of relief structures, preparation and analysis of technology of implementation of relief structures with regard to the limits of current scientific instruments, verification of theoretical considerations by means of relief structure sample exposure. Keywords: diffractive optical structures; relief structure; e-beam lithography Available at various institutes of the ASCR
SMV-2017-01: Reliéfní struktury na principu difraktivní optiky

Výzkum a vývoj v oblasti fyzikální realizace grafických a optických struktur na principu difraktivní optiky prostředky elektronové litografie v záznamovém materiálu neseném křemíkovou nebo skleněnou ...

Horáček, Miroslav; Kolařík, Vladimír; Matějka, Milan; Krátký, Stanislav; Chlumská, Jana; Meluzín, Petr; Král, Stanislav
Ústav přístrojové techniky, 2017

Phyllotactic Model Linking Nano and Macro World
Horáček, Miroslav; Meluzín, Petr; Krátký, Stanislav; Urbánek, Michal; Bok, Jan; Kolařík, Vladimír
2017 - English
Recently, the arrangement of diffraction primitives according to a phyllotactic model was presented. This arrangement was used to benchmarking purposes of the e-beam writer nano patterning. The phyllotactic arrangement has several interesting properties. One of them is related with the coherence between the nanoor microscopic domain of individual optical primitives and the properties of visually perceived images crated by these structures in the macro domain. This paper presents theoretical analysis of the phyllotactic arrangement in the referred context. Different approaches enabling the creation of diffractive optically variable images are proposed. The practical part of the presented work deals with the nano patterning of such structures using two different types of the e-beam pattern generators. One of them is a system with a variable shaped beam of electrons, while the other one is a system with a Gaussian-shaped beam. E-beam writing strategies and the use of inherent spiral patterns for exposure ordering and partitioning are also discussed. Keywords: nano patterning; spiral grating structure; phyllotactic pattern; e-beam writer Available at various institutes of the ASCR
Phyllotactic Model Linking Nano and Macro World

Recently, the arrangement of diffraction primitives according to a phyllotactic model was presented. This arrangement was used to benchmarking purposes of the e-beam writer nano patterning. The ...

Horáček, Miroslav; Meluzín, Petr; Krátký, Stanislav; Urbánek, Michal; Bok, Jan; Kolařík, Vladimír
Ústav přístrojové techniky, 2017

Examination of 2D crystals in a low voltage SEM/STEM
Mikmeková, Eliška; Frank, Luděk; Polčák, J.; Paták, Aleš; Lejeune, M.
2017 - English
Development of new types of materials such as 2D crystals (graphene, MoS2, WS2, h-BN, etc.) requires emergence of new surface-sensitive techniques for their characterization. As regards the “surface” sensitivity, the (ultra) low energy electron microscopy can become a very powerful tool for true examination of these atom-thick materials, capable of confirming physical phenomena predicted to occur on their surfaces. Modern commercial scanning electron microscopes enable imaging and analyses by low energy electrons even at very high magnification. In the case of the SEM, resolution even below 1 nm can be achieved at low landing energy of electrons. Since specimen contamination increases with increasing electron dose and decreasing landing energy, specimen cleanness is a critical factor in obtaining meaningful data. A range of various specimen cleaning methods can be applied to selected samples. Typical cleaning methods, such as solvent rinsing, heating, bombarding with ions and plasma etching have their limitations. Electron-induced in situ cleaning procedure can be gentle, experimentally convenient and very effective for wide range of specimens. Even a small amount of hydrocarbon contamination can severely impact on the results obtained with low energy electrons, as illustrated in Figure 1A. During the scanning of surfaces by electrons, the image usually darkens because of a carbonaceous layer gradually deposited on the top from adsorbed hydrocarbon precursors. Keywords: low voltage SEM/STEM; 2D crystals; contamination Available at various institutes of the ASCR
Examination of 2D crystals in a low voltage SEM/STEM

Development of new types of materials such as 2D crystals (graphene, MoS2, WS2, h-BN, etc.) requires emergence of new surface-sensitive techniques for their characterization. As regards the “surface” ...

Mikmeková, Eliška; Frank, Luděk; Polčák, J.; Paták, Aleš; Lejeune, M.
Ústav přístrojové techniky, 2017

K-space trajectory calibration for improved precision of quantitative ultrashort echo time imaging
Latta, P.; Starčuk jr., Zenon; Gruwel, M.; Tomanek, B.
2017 - English
Ultrashort echo time imaging (UTE) is often the method of choice for measurement of short-lived T2 signals from biological tissues. The UTE acquisition is based on radial or spiral sampling schemes which, in general, are sensitive to small discrepancies between prescribed and actual trajectories. Such errors are usually observed as image quality degradation, visible as ghosting or intensity variation. This is even more serious for quantitative applications when intensity variation can cause serious bias in the estimation of measured parameters such as proton density (PD). Here we investigate such behavior of UTE acquisition and demonstrate that proper calibration of the gradient channels could minimize these type of the errors. Phantom experiments proved the efficiency of the application trajectory calibration approach. Keywords: ultrashort Echo Time (UTE); K-space Trajectory Calibration; proton Density Available at various institutes of the ASCR
K-space trajectory calibration for improved precision of quantitative ultrashort echo time imaging

Ultrashort echo time imaging (UTE) is often the method of choice for measurement of short-lived T2 signals from biological tissues. The UTE acquisition is based on radial or spiral sampling schemes ...

Latta, P.; Starčuk jr., Zenon; Gruwel, M.; Tomanek, B.
Ústav přístrojové techniky, 2017

Impaktní odolnost nanokompozitivních Mo-B-C a W-B-C povlaků připravených metodou magnetronového naprašování
Fořt, Tomáš; Grossman, Jan; Daniel, Josef; Sobota, Jaroslav; Dupák, Libor; Buršíková, V.; Zábranský, L.; Souček, L.; Mirzaei, S.; Alishahi, M.; Vašina, P.; Buršík, Jiří
2017 - Czech
V poslední době se díky svým význačným vlastnostem stávají ternární vrstvy boridů a karbidů X-B-C (X = Mo, W a Ta) objektem výzkumu jak na úrovni teoretických výpočtů, tak experimentálních prací. V případě stechiometrie mají vrstvy X2BC s X = Mo, W a Ta díky své výrazné tuhosti a houževnatosti velký potenciál pro uplatnění jako ochranné povlaky řezných a obráběcích nástrojů. Tato práce je zaměřena na nanostrukturované Mo-B-C a W-B-C vrstvy nanesené magnetronovým naprašováním na substrát z rychlořezné oceli (HSS). Mechanické vlastnosti vrstev byly zjištěny nanoindentační zkouškou jak ve statickém, tak v dynamickém režimu. V práci je diskutován elastický modul, tvrdost vrstev a jejich odolnost vůči vzniku trhlin. Výsledky odolnosti Mo-B-C a W-B-C vrstev vůči vzniku a šíření trhlin z indentačních zkoušek byly srovnány s výsledky z dynamických impaktních testů. Recently, based on attractive mechanical properties of boride and carbide based X2BC ternary compounds (X = Mo, W and Ta) they became subjects of both theoretical calculations and experimental work. In the case of stoichiometric composition, X2BC with X = Mo, W and Ta are very promising candidates for protection of cutting and forming tools due to their unusually stiffness and moderate ductility.\nIn this work we focus on nanostructured Mo-B-C and W-B-C layers grown by magnetron sputtering on high speed steel (HSS) substrates. Mechanical properties of the layers were characterized by nanoindentation experiments in both static and dynamic loading regimes. Elastic modulus, indentation hardness and fracture resistance were evaluated and discussed. The fracture resistance of both Mo-B-C and W-B-C coatings was compared using both indentation and dynamic impact tests.\n Keywords: impact test; nanoindentation test; magnetron sputtering; Mo-B-C; W-B-C Available at various institutes of the ASCR
Impaktní odolnost nanokompozitivních Mo-B-C a W-B-C povlaků připravených metodou magnetronového naprašování

V poslední době se díky svým význačným vlastnostem stávají ternární vrstvy boridů a karbidů X-B-C (X = Mo, W a Ta) objektem výzkumu jak na úrovni teoretických výpočtů, tak experimentálních prací. V ...

Fořt, Tomáš; Grossman, Jan; Daniel, Josef; Sobota, Jaroslav; Dupák, Libor; Buršíková, V.; Zábranský, L.; Souček, L.; Mirzaei, S.; Alishahi, M.; Vašina, P.; Buršík, Jiří
Ústav přístrojové techniky, 2017

Nežádoucí metabolické účinky aripiprazolu v poly I:C modelu schizofrenie u potkana
Horská, K.; Rudá-Kučerová, J.; Dražanová, Eva; Pistovčáková, J.; Karpíšek, M.; Kotolová, H.; Demlová, R.; Kašpárek, T.
2017 - English
The aim of this study was to evaluate metabolic phenotype of poly I:C rat model and asses metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of energy homeostasis. Altered lipid profile in poly I:C model was observed. Leptin and GLP-1 serum levels were significantly reduced, while ghrelin level was elevated. Our data indicate that dysregulation of adipose tissue endocrine function and gastrointestinal hormones is implicated in metabolic adverse effects of antipsychotics. Keywords: metabolic syndrome; aripiprazole; rat; poly I:C animal model Available at various institutes of the ASCR
Nežádoucí metabolické účinky aripiprazolu v poly I:C modelu schizofrenie u potkana

The aim of this study was to evaluate metabolic phenotype of poly I:C rat model and asses metabolic effects of chronic aripiprazole treatment with regard to complex neuroendocrine regulations of ...

Horská, K.; Rudá-Kučerová, J.; Dražanová, Eva; Pistovčáková, J.; Karpíšek, M.; Kotolová, H.; Demlová, R.; Kašpárek, T.
Ústav přístrojové techniky, 2017

Study of laser wobbling welding process through the radiation of plasma plume
Mrňa, Libor; Horník, Petr; Jedlička, Petr; Pavelka, Jan
2017 - English
During laser welding with wobbling to the vector of the welding speed adds trivial movement of the beam in the shape of a circle or other shapes. Therefore, the laser beam moves with much higher current speeds than during normal welding. The melting of material on the leading edge of the keyhole occurs periodically. This fact is reflected in the character of the radiation of plasma plume over the keyhole. Experiments were conducted in which it was obtained spectrum of plasma plume radiation by using autocorrelation function for different parameters of circular wobbling (circle diameter, frequency) and for different materials. In the spectra are found the higher harmonic frequency of wobbling. The results were also compared with the radiation of the plasma plume during pulsed laser welding where the laser beam also periodically melts the leading edge. Keywords: laser welding; wobbling; process monitoring Available at various institutes of the ASCR
Study of laser wobbling welding process through the radiation of plasma plume

During laser welding with wobbling to the vector of the welding speed adds trivial movement of the beam in the shape of a circle or other shapes. Therefore, the laser beam moves with much higher ...

Mrňa, Libor; Horník, Petr; Jedlička, Petr; Pavelka, Jan
Ústav přístrojové techniky, 2017

SMV-2017-22: Realizace víceosého interferometrického systému pro souřadnicové odměřování
Holá, Miroslava; Lazar, Josef; Hucl, Václav; Čížek, Martin
2017 - Czech
Cílem projektu smluvního výzkumu bylo realizovat víceosý interferometrický systém pro souřadnicové odměřování. Jedná se o systém umožňující bezkontaktní měření polohy (posunutí) v osách x, y s kompenzací vlivu indexu lomu vzduchu. Důraz byl kladen na vysokou přesnost a opakovatelnost měření na nanometrové úrovni pro vlnovou délku 633 nm. Součástí projektu byl také vývoj a realizace řídící elektroniky pro detekci signálu pomocí homodynního kvadraturního detekčního systému. Celý systém byl testován v laboratorních podmínkách a poté instalován do příslušného systému v zadavatelské firmě. The aim of the project of the contractual research was development of a multiaxis interferometric system for coordinate measurement. This system make possible to contactless measurement of displacement in axis x, y with compensation refractive index of air. The emphasis was placed on with high accuracy and repeatability measurement on nanometre level for wavelength 633 nm. Part of the contractual research was development and realization driving system for detection of signals. We used homodyne detection system. The measurement system was tested in laboratory and then was installed in the aim system. Keywords: interferometry; refractive index of air; laser measurement Available at various institutes of the ASCR
SMV-2017-22: Realizace víceosého interferometrického systému pro souřadnicové odměřování

Cílem projektu smluvního výzkumu bylo realizovat víceosý interferometrický systém pro souřadnicové odměřování. Jedná se o systém umožňující bezkontaktní měření polohy (posunutí) v osách x, y s ...

Holá, Miroslava; Lazar, Josef; Hucl, Václav; Čížek, Martin
Ústav přístrojové techniky, 2017

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