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Chromatická vada několika význačných refraktorů 19. a 20. století
Rail, Zdeněk; Jareš, Daniel; Tomka, David; Doleček, Roman
2013 - Czech
V 19. století dominovaly v astronomii refraktory. Čočky těchto přístrojů byly vyráběny z klasických skel a proto jejich dominantní zbytkovou vadou byl sekundární chromatismus. V této práci jsou ukázány zbytkové vady několika refraktorů, u kterých se podařilo sehnat jejich optické parametry. Jedná se o 40, 36 a 25 palcové refraktory Alvana Clarka, Yerkesovy, Lickovy a USNO observatoře, 12 palcový refraktor hvězdárny v Greenwiche a dále 6 palcový heliometr Josefa Fraunhofera v Königsbergu, se kterým byla poprvé změřena paralaxa hvězdy. Referát obsahuje také parametry objektivu Königova dalekohledu, petřínské hvězdárny v Praze. In 19th century refractors dominated in astronomical research. Lenses of these devices were made of the classical glasses. Main optical aberration of these telescopes was residual chromatism. In this paper residual chromatism of several important refractors is shown. We managed to get optical parameters of 40, 36, 25 inch refractors of Alvan Clark, 12 inch telescope of Greenwiche observatory and 6 inch heliometer of Joseph Fraunhofer with which paralax of star was measured for the first time. The paper contains parameters of the dublet of König telescope of Prague‘s observatory
Keywords:
Optical design of refractor achromatic objective lenses, aplanatic objective; residual chromatism, achromatic objective of Alvan Clark; Fraunhofer objective, the 12 inch Greenwiche refractor; König telescope of Prague Observatory; Fraunhofer heliometer; classical glasses; the 40 inch Refractor; the 36 inch Refractor; the refractor of USNO
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Chromatická vada několika význačných refraktorů 19. a 20. století
V 19. století dominovaly v astronomii refraktory. Čočky těchto přístrojů byly vyráběny z klasických skel a proto jejich dominantní zbytkovou vadou byl sekundární chromatismus. V této práci jsou ...
Heat and Particle Deposition on the Plasma-Facing Components
Podolník, Aleš; Pánek, Radomír; Komm, Michael; Dejarnac, Renaud; Gunn, J. P.
2013 - English
The interaction of plasma with plasma-facing components (PFCs) in tokamaks is of increasing interest because of implications for ITER and next-step devices. The heat and particle fluxes interacting with solid objects can be studied by means of particle-in-cell (PIC) simulations. The aim of this work is to use the existing family of PIC codes SPICE to simulate the heat and particle flux distribution on PFCs. The output of the simulations is then used in new heat equation solver, which calculates the temperature of the PFCs. This solver provides us a testbed for the parallel sparse matrix code development as well as for the complex application aimed at study of the melting of tiles.
Keywords:
plasma; tokamak; ITER
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Heat and Particle Deposition on the Plasma-Facing Components
The interaction of plasma with plasma-facing components (PFCs) in tokamaks is of increasing interest because of implications for ITER and next-step devices. The heat and particle fluxes interacting ...
First measurements with U-probe on the COMPASS tokamak
Kovařík, Karel; Ďuran, Ivan; Stöckel, Jan; Seidl, Jakub; Šesták, David; Brotánková, J.; Spolaore, M.; Martines, E.; Vianello, N.
2013 - English
A complex electrostatic-magnetic probe diagnostics, baptized as ‘U-probe’, has been installed on COMPASS tokamak recently. Probe composes of two identical towers. Each tower houses 3 radially spaced sets of 3D coils, triple probe and rake probe – array of six Langmuir probes. The U-probe measures electric and magnetic properties of the filamentary structures in the edge plasma, particularly the floating potential profile and local magnetic field within the plasma filaments. Contribution presents first tests and results obtained.
Keywords:
plasma; tokamak
Fulltext is available at external website.
First measurements with U-probe on the COMPASS tokamak
A complex electrostatic-magnetic probe diagnostics, baptized as ‘U-probe’, has been installed on COMPASS tokamak recently. Probe composes of two identical towers. Each tower houses 3 radially spaced ...
Dust Observation in the COMPASS Tokamak Using Fast Camera
Odstrčil, M.; Mlynář, Jan; Weinzettl, Vladimír; Háček, Pavel; Berta, M.; Szabolics, T.; Bencze, A.
2013 - English
The dust grains were observed over a thousand discharges in the tokamak COMPASS. A novel method for semi-automatic extraction and tracking of dust grains using a relatively low frame-rate camera (370 fps) was proposed. Radiation lifetime, time evolution and the acceleration of the dust grains were studied. The measured dust velocities roughly correspond to a simple model. However, slow dust particles are signicantly aected by local plasma properties and initial release conditions that cannot be determined in our experiment
Keywords:
COMPASS; tokamak
Fulltext is available at external website.
Dust Observation in the COMPASS Tokamak Using Fast Camera
The dust grains were observed over a thousand discharges in the tokamak COMPASS. A novel method for semi-automatic extraction and tracking of dust grains using a relatively low frame-rate camera ...
Possible way to prepare nanoparticles from aerosols released at plasma deposition
Brožek, Vlastimil; Mastný, L.; Moravec, Pavel; Ždímal, Vladimír
2012 - English
During plasma deposition of powdered metals or inorganic compounds using WSP® generator, they interact with the plasma having temperature between 25000 and 30000 K. As a result, they melt, evaporate, thermally decompose, get ionized and/or react chemically both with plasma-forming medium and with the surrounding atmosphere or carrier gas. An experimental apparatus was constructed enabling us to capture aerosol particles emitted from the surface of the free flying particles (FFP) heated in a stream of plasma. In this work we studied content, composition and size distribution of nanosized particles of Ag and oxides of Al, Ti, Cr and W, released during plasma deposition process. These particles were analyzed by dynamic light scattering - photon correlation spectroscopy using instrument MALVERN, and with aerosol spectrometers SMPS 3936 and APS 3321.Concentration of aerosols containing nanoparticles of silver or metal oxides with diameters below 100 nm was found to be in the range 85 to
Keywords:
plasma spraying; aerosol technology; nanoparticles production; measurement of particle size distribution
Fulltext is available at external website.
Possible way to prepare nanoparticles from aerosols released at plasma deposition
During plasma deposition of powdered metals or inorganic compounds using WSP® generator, they interact with the plasma having temperature between 25000 and 30000 K. As a result, they melt, evaporate, ...
Production of nanoparticles utilizing water stabilized plasma
Bertolissi, Gabriele; Brožek, Vlastimil; Chráska, Tomáš; Mušálek, Radek; Neufuss, Karel; Mastný, L.; Sofer, Z.
2012 - English
Water stabilized plasma torch (WSP®) generates plasma jet with max. plasma velocity in the nozzle exit 7000m/s and temperature of 25000-30000 K. Reactants injected into the plasma jet undergo complicated radical reactions. Interaction of plasma with injected reactants depends on energy settings of the WSP plasma torch and lasts from 5 to 10 ms. Droplets of inorganic compound solution are fed to the plasma jet by pressurized spray nozzle device. Compounds of AgI,AlIII,TiIV,PtIV,VV, and CrVI undergo decomposition in the extremely high plasma temperature and the decomposed products are collected in liquid separators. Size of the produced nanoparticles in unsettled fraction is from 10 to 200 nm and depends primarily on concentration of inputting aerosol particles. In the case of 15 seconds reaction time and use of saturated solutions at 20°C, one can obtain colloidal solutions with silver, platinum, alumina, titania, vanadia, and chromia nanoparticles in concentrations of 3 to 180mg
Keywords:
Ag, Al, Ti, V, Cr, Pt – nanoparticles; nanoparticles morphology; plasma spraying; water stabilized plasma; photon spectroscopy; metallic nanoparticles; oxide nanoparticles
Fulltext is available at external website.
Production of nanoparticles utilizing water stabilized plasma
Water stabilized plasma torch (WSP®) generates plasma jet with max. plasma velocity in the nozzle exit 7000m/s and temperature of 25000-30000 K. Reactants injected into the plasma jet undergo ...
Using matlab for visualization of plasma dynamics by statystical processing of photograph sequences
Chumak, Oleksiy; Hrabovský, Milan
2011 - English
Short exposure photographs capturing the momentary state of the plasma radiation are often used for the primary characterization of discharges. Sequence of such images gives an impression about a variation of radiation intensity in different areas and can be used to describe the fluctuation intensity. This work presents a statistical procedure which produces brightness fluctuation intensity maps. Two realizations of the statistical procedure in Matlab environment are described and compared.
Keywords:
Plasma stability; jet fluctuations; statistical processing; entropy maps
Fulltext is available at external website.
Using matlab for visualization of plasma dynamics by statystical processing of photograph sequences
Short exposure photographs capturing the momentary state of the plasma radiation are often used for the primary characterization of discharges. Sequence of such images gives an impression about a ...
Zbytkové optické vady Clarkova osmipalcového objektivu z Ondřejova
Rail, Zdeněk; Jareš, Daniel; Lédl, Vít
2011 - Czech
Referát se zabývá zbytkovými vadami historického Clarkova osmipalcového (průměr 203 mm) objektivu z Astronomického ústavu AV ČR,v.v.i.v Ondřejově. V roce 1999 byl objektiv ve Vývojové optické dílně AV ČR rozebrán, vyčištěn a u čoček byly proměřeny optické parametry,umožňující matematickou simulaci dubletu. This paper deals with residual aberrations of Clark 8“ (diameter 203 mm) lens of Astronomical Institute of AS CR,v.v.i. in Ondřejov. Objective was disassembled and cleaned in Development Optical Workshop of AS CR in Turnov in 1999. During this process optical parameters of lenses were measured and this makes possible to evaluate mathematical simulation of this dublet.
Keywords:
Residual aberrations of Clark 8“ telescope of Ondřejov; Alvan Clark
Fulltext is available at external website.
Zbytkové optické vady Clarkova osmipalcového objektivu z Ondřejova
Referát se zabývá zbytkovými vadami historického Clarkova osmipalcového (průměr 203 mm) objektivu z Astronomického ústavu AV ČR,v.v.i.v Ondřejově. V roce 1999 byl objektiv ve Vývojové optické ...
Katadioptrické soustavy Argunova, Popova a Klevcova
Rail, Zdeněk; Jareš, Daniel; Lédl, Vít
2011 - Czech
Referát se zabývá dvojzrcadlovými soustavami Argunova, Popova a Klevcova, s meniskovými korektory ve sbíhavém svazku, vloženými poblíž sekundárních zrcadel. Takové soustavy umožňují konstrukci přístrojů s vysokým stupněm korekce optických vad. Několik dalekohledů tohoto typu se dnes komerčně vyrábí a patří k nejlépe vykorigovaným katadioptrickým soustavám. This paper deals with two-mirror systems of Argunov, Popov and Klevcov which use meniscus correctors in convergent beam of light placed near their secondaries. These systems make possible to construct of highly aberration corrected devices. Several telescopes of this type are producted commercialy and belong to the best corrected catadioptric systems.
Keywords:
Catadioptric systems of Argunov; Popov and Klevcov
Fulltext is available at external website.
Katadioptrické soustavy Argunova, Popova a Klevcova
Referát se zabývá dvojzrcadlovými soustavami Argunova, Popova a Klevcova, s meniskovými korektory ve sbíhavém svazku, vloženými poblíž sekundárních zrcadel. Takové soustavy umožňují konstrukci ...
Zvýšení rozlišovací schopnosti malých chromosférických dalekohledů
Melich, Radek; Rail, Zdeněk; Melich, Zbyněk
2011 - Czech
Byla navržena Mersenova předsádka k nasazení na komerční typy chromosférických dalekohledů (například typ Coronado), s cílem zvětšení rozlišovací schopnosti přístroje. Původní dalekohled s aperturou 40 mm, tj. s rozlišovací schopností 4“, byl doplněn afokální soustavou průměru 120 mm. Bylo zjištěno, že rozlišení při dobrém seengu odpovídá výsledkům blízkým teoretickým, tedy 1.2“. The improvement of resolving power of small chromospheric telescopes. The Mersen system was constructed for improvement of resolving power of commercial solar chromospheric telescopes (Coronado, Lunt). Former device of aperture of 40 mm and resolving power 4“ was equipped with entral member – afocal Mersen system of 120 mm diameter. Resolving power of composed systém was increased to 1.2“ which was observed during good seeing conditions.
Keywords:
chromospheric telescopes; Mersen system
Fulltext is available at external website.
Zvýšení rozlišovací schopnosti malých chromosférických dalekohledů
Byla navržena Mersenova předsádka k nasazení na komerční typy chromosférických dalekohledů (například typ Coronado), s cílem zvětšení rozlišovací schopnosti přístroje. Původní dalekohled s aperturou ...
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