No (543)
Number of found documents:
543
Published from
to
XUV Spectra from High Current Nitrogen Z-Pinch Capillary Discharge.
Vrba, Pavel; Vrbová, M.
2017 - English
We have performed computer modeling of the pinching plasma of capillary discharge using the 1d NPINCH code, that considers ablation of the capillary wall. At high currents we have observed that, the ablation has significant effect on the plasma electron temperature evolution and on the rate of pinch decay. To estimate the emitted spectra in XUV range, the FLYCHK code was used as a post processor. The capillary wall ablation represents the principal obstacles of recombination pumping during pinch decay.\n
Keywords:
MHD and RMHD simulations of high current capillary discharge; Z-pinches; water window radiation; capillary wall ablation
Available at various institutes of the ASCR
XUV Spectra from High Current Nitrogen Z-Pinch Capillary Discharge.
We have performed computer modeling of the pinching plasma of capillary discharge using the 1d NPINCH code, that considers ablation of the capillary wall. At high currents we have observed that, the ...
The investigation of an Al-Zr-Ti alloy prepared by spark plasma sintering of atomized powder
Molnárová, O.; Málek, P.; Lukáč, František; Chráska, Tomáš; Cinert, Jakub
2017 - English
The microstructure and mechanical properties of a powder metallurgical Al-Zr-Ti alloy was studied. Fine powder with a typical size below 50 ?m was prepared by gas atomization. The smallest powder particles with a diameter below 10 ?m exhibited a segregation free microstructure. Larger droplets were found to contain intermetallic particles rich in Zr and Ti. The gas atomized powder was consolidated by spark plasma sintering (SPS) at various temperatures ranging from 450 to 550 °C. During SPS the materials microstructure remained nearly unchanged and a fine grain size between 2 and 3 ?m was observed. All SPS samples exhibited a microhardness of around 90 HV. The annealing (1 h, 500 °C) of the sample sintered at the highest temperature (550 °C) resulted in a decrease of microhardness to 75 HV as a result of changes in the phase composition, the fine grain size was retained. Natural aging at room temperature was not observed.
Keywords:
Gas atomization; High strength alloy; Spark plasma sintering; Thermal stability
Available at various institutes of the ASCR
The investigation of an Al-Zr-Ti alloy prepared by spark plasma sintering of atomized powder
The microstructure and mechanical properties of a powder metallurgical Al-Zr-Ti alloy was studied. Fine powder with a typical size below 50 ?m was prepared by gas atomization. The smallest powder ...
Neostel collimator realization detailed optical design
Lédl, Vít; Pleštil, Jan; Psota, Pavel; Steiger, Lukáš; Václavík, Jan; Tomáš, V.
2017 - English
The aim of this document is to describe the optical design of the Alignment Collimator for the NEOSTEL telescope. The document describes proposed optical and mechanical design. It consists of several parts: Optical design and its tolerance analysis, Ghost image analysis, Stray light analysis, Mechanical design and FEM analysis.
Keywords:
collimator; FEM; alignment; telescope; optical design
Available at various institutes of the ASCR
Neostel collimator realization detailed optical design
The aim of this document is to describe the optical design of the Alignment Collimator for the NEOSTEL telescope. The document describes proposed optical and mechanical design. It consists of several ...
Surface profilometry by digital holography
Psota, Pavel; Lédl, Vít; Kaván, František; Matoušek, O.; Mokrý, P.
2017 - English
This paper presents newly developed method for measurement of surface topography based on frequency scanning digital holography. Digital holography allows for direct computation of the phase field of the wavefront scattered by an object. A tuning of the light source optical frequency results in linear phase variation with respect to the optical frequency. Slope of the linear function in every single pixel corresponds to absolute measurement of optical path difference and thus topography map of the surface can be retrieved. Principle of this contactless method is introduced and experimentally verified. The method can be used for measurement of complex geometries of common manufacturing parts as well as for topography measurement of complex composite structures, and active acoustic metasurfaces.
Keywords:
Surface profilometry; Digital holography; Frequency scanning; Absolute measurement
Available at various institutes of the ASCR
Surface profilometry by digital holography
This paper presents newly developed method for measurement of surface topography based on frequency scanning digital holography. Digital holography allows for direct computation of the phase field of ...
CNT composite - polishing methods and metalic coating
Thoř, Tomáš; Václavík, Jan; Vápenka, David
2017 - English
This study summarizes R&D tasks done in order to develop technology for polishing and metallic coating of CNT composite for optical and radiofrequency applications. Development was done on two types of material samples:\n- Material for the MIRROR demonstrator\n- Material for the FEEDHORN demonstrator
Keywords:
polishing; cnt composite; metallic coating
Available at various institutes of the ASCR
CNT composite - polishing methods and metalic coating
This study summarizes R&D tasks done in order to develop technology for polishing and metallic coating of CNT composite for optical and radiofrequency applications. Development was done on two types ...
Mechanical properties of plasma sprayed layers of NiAl10 and NiAl40 on AZ91 alloy
Kubatík, Tomáš František; Brodil, R.; Ctibor, Pavel; Průša, F.; Brožek, Vlastimil
2017 - English
In this work, plasma coatings of NiAl10 and NiAl40 on magnesium alloy AZ91 substrate were prepared by the hybrid plasma spraying system WSP®-H 500. The both plasma sprayed coatings of NiAl10 and NiAl40 have metallurgical bond. The thicknesses of microstructures in the cross-section of NiAl10 and NiAl40 plasma sprayed coatings prepared by 9 passes were 374 and 440 μm respectively. Adhesion test of plasma sprayed layers was performed using a modified ASTM C 633 standard. The tensile adhesion strength values are 24.7 MPa for NiAl10 coatings and 12.3 MPa for NiAl40 coatings. Abrasion resistance according to Slurry Abrasion Response (SAR) test of NiAl40 layers had similar values (0.12 g/cm2)in a comparison with the uncoated AZ91 (0.126 g/cm2). Layers NiAl10 had greater weight losses (0.175 g/cm2) than uncoated AZ91. Microhardness of plasma coating of NiAl40 is several times greater than microhardnesses of plasma coating of NiAl10 and uncoated substrate AZ91
Keywords:
Adhesion strength; Nickel alloys; Plasma spraying; Wear resistance
Available at various institutes of the ASCR
Mechanical properties of plasma sprayed layers of NiAl10 and NiAl40 on AZ91 alloy
In this work, plasma coatings of NiAl10 and NiAl40 on magnesium alloy AZ91 substrate were prepared by the hybrid plasma spraying system WSP®-H 500. The both plasma sprayed coatings of NiAl10 and ...
Large displacement and deformation measurement by frequency sweeping digital holography
Psota, P.; Lédl, Vít; Kaván, František; Matoušek, O.; Doleček, R.
2017 - English
Recently, a digital holographic method called Frequency Sweeping Digital Holography (FSDH) for high precision measurements of surface topography of mechanical parts has been introduced. The greatest advantage of the presented FSDH is the fact that the measurement is absolute. i.e. optical path difference is independently retrieved in every single pixel. This approach can therefore be used also for measurement of large displacements and deformation. FSDH is particularly suitable in cases where the common digital holographic methods fail due to e.g. 2π unambiguity problem or speckle decorrelation. Measurement method principles, setup details, an some features of the method are discussed.\n
Keywords:
Digital holography; Digital holographic interferometry; Displacement measurement; Absolute measurements
Available at various institutes of the ASCR
Large displacement and deformation measurement by frequency sweeping digital holography
Recently, a digital holographic method called Frequency Sweeping Digital Holography (FSDH) for high precision measurements of surface topography of mechanical parts has been introduced. The greatest ...
Virtuální zobrazení vzdálených objektů dlouhofokálními spojkami a konkávními zrcadly
Rail, Zdeněk; Vápenka, David
2016 - Czech
Dlouhofokální spojky a konkávní zrcadla mohou sloužit jako optické prvky, úhlově zvětšující rozměry vzdálených objektů podobně jako dalekohledy. Tyto jejich vlastnosti mohly být pravděpodobně používány pozorovateli dávno před objevem dalekohledu. Naše práce přináší optickou analýzu a výsledky astronomických pozorování soustavou dlouhofokální positivní čočky a lidského oka. The longfocal positive lenses and concave mirrors can serve as optical elements increasing the angular dimensions of the distant objects similarly to telescope.\nThese properties could be probably used by ancient observers before the discovery of telescope.\nOur paper brings optical analysis and results of visual astronomical observations with the longfocal positive lens.
Keywords:
Real and virtual imaging; Angular magnification; Ibn al-Haytham; Benjamin of Tudela; Roger Bacon; Giambattista della Porta; Johann Lippershey; Galileo; Kepler; Longfocal lens; Lighthouse on Pharos island; Ancient lenses; Šolc mirror; Camera obscura; Longfocal lens observation
Available at various institutes of the ASCR
Virtuální zobrazení vzdálených objektů dlouhofokálními spojkami a konkávními zrcadly
Dlouhofokální spojky a konkávní zrcadla mohou sloužit jako optické prvky, úhlově zvětšující rozměry vzdálených objektů podobně jako dalekohledy. Tyto jejich vlastnosti mohly být pravděpodobně ...
Methodology of camera spectral response measurement
Melich, Radek; Václavík, Jan; Žídek, Karel
2016 - English
Spectral response of the camera will be measured using monochromator in conjunction with an integration sphere. Camera without objective will be placed in one port of the integrating sphere and light beam from monochromator will be fed into perpendicular port. Sensor of the camera sensor will be therefore uniformly illuminated by diffused light from monochromator. Proposed FWHM of the monochromator is 15 nm as a trade-off between light intensity provided by monochromator and deformation of spectral characteristic (Picture XY). Diameter of the integrating sphere has to be larger than 100 mm to ensure uniform illumination over sensor area.
Keywords:
Camera spectral response
Available at various institutes of the ASCR
Methodology of camera spectral response measurement
Spectral response of the camera will be measured using monochromator in conjunction with an integration sphere. Camera without objective will be placed in one port of the integrating sphere and light ...
Evaluation of selected parameters of a LIBA2000 glass melt according to ISO 12123.
Václavík, Jan
2016 - English
Measurement of refractive indices of samples, specifically refractive indicies nd, ne and Abbe numbers for spectral lines d and e. Assesment of refractive index variation, internal spectal transmitance and amount of striae in samples.\n
Keywords:
glass melt; ISO 12123; striae; refractive index; inhomogeneity
Available at various institutes of the ASCR
Evaluation of selected parameters of a LIBA2000 glass melt according to ISO 12123.
Measurement of refractive indices of samples, specifically refractive indicies nd, ne and Abbe numbers for spectral lines d and e. Assesment of refractive index variation, internal spectal ...
NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web
Send your suggestions and comments to nusl@techlib.cz
Provider
Other bases