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Two-phase (B2+L1 2 ) nickel aluminide intermetallic compounds were synthesized by the pressure-assisted volume combustion synthesis (CS). The production and characterization of the samples containing NiAl+Ni 3 Al were investigated. Aluminum (99% pure, 15μm) and carbonyl nickel (99.8 pure, 4–7μm) powders were used. The production of intermetallic compound was carried out at 1050°C under...
The dielectric properties and the AC conductivity of [Cd(phen)2(SCN)2] were investigated as a function of frequency and temperature. The dielectric properties were studied in the frequency range of 103–106Hz and in the temperature range of 298–588K. The AC conductivity was found to obey the universal power law. The variation of the exponent s with the temperature has showed that correlated barrier...
This paper provides an analytical solution for three-dimensional model predicting temperature in the welding cavity of electron beam. It is not easy to measure the temperature on the keyhole of electron-beam welding. Therefore it is essential to develop an analytical model that can accurately predict the temperature in the keyhole. In this study, the keyhole produced by an electron beam is assumed...
Zn-doped TiO 2 films were prepared by means of pulsed DC reactive magnetron sputtering method using Ti and Zn mixed target. The deposition condition was optimized to produce uniform and transparent TiO 2 films. Titanium was in the Ti 4+ oxidation state in all Zn-doped TiO 2 films. The zinc oxide deposited on the substrate was in the fully oxidized state of ZnO. Increase...
The present paper reports the results of studying the characteristics of the etching process of multi-layered materials (Si 3 N 4 /SiO 2 /Si and SiO 2 /Si) and of cleaning technological chambers covered with silicon nitride films (Si 3 N 4 ) in a NF 3 RF capacitive discharge. The process of chamber cleaning was monitored with a mass spectrometer...
In this paper, we compare theoretically, as well as experimentally, four constructions of quantum well (QW) AlGaAs/InGaAs/GaAs semiconductor lasers: one standard, simple separate confinement heterostructure (SCH) laser and three different GRIN SCH (graded index separate confinement heterostructure) lasers. By optimising the construction and technology of epitaxy, an increase of laser quantum efficiency...
New prototypes and concepts of microstructured vacuum gauges have been developed by using the fabrication technologies for micro electro mechanical systems (MEMS). The realization of such microstructured gauges requires sophisticated fabrication processes such as thin film deposition, photolithography and etching techniques. This approach of MEMS vacuum gauges is demonstrated by a few examples.Micro-Pirani...
Ion–beam-loss induced desorption is a well known intensity limitation for high current, low charge state heavy ion accelerators like the heavy ion synchrotron SIS18 at GSI. Therefore dedicated measurements of desorption yields has been made, e.g., at CERN and at GSI in the last few years. In this work we will present studies performed at GSI starting from purely phenomenological pressure rise experiments...
Current “Non-evaporable getters” (NEGs) are important for the improvement of vacuum by the help of metallic surface sorption of residual gas molecules. High porosity alloys or powder mixtures of Zr, Ti, Al, V, Fe and other metals are the base material for this kind of gas sorbents. The development of vacuum technologies creates new challenges for the field of getter materials. The main sorption parameters...
We report on various aspects of the application of functionally graded materials (FGM) for devices fabrication. The broad spectrum of problems ranging from design and technology of graded structures to its characterization is discussed. The main attention is focused on the application of FGM as an active area of a new photo-detector. The influence of various profile distributions of AIIIBV grading...
Early stages of Cr contact formation on 6H-SiC(0001) were investigated using the atomic force microscope (AFM) and current-sensing AFM with conducting tip. Cr layers were vapor deposited under ultrahigh vacuum onto samples cut out of a single crystal of n-type 6H-SiC(0001) that were ex situ hydrogen etched in a tubular flow reactor. Topography of the samples, their local conductance patterns and local...
Pd nanocrystals obtained by the physical vacuum deposition (PVD) method were studied by X-ray diffraction, transmission electron microsocpy (TEM), atomic force microsocpy (AFM) and optical absorption methods. These Pd fcc nanocrystals are embedded in carbonaceous matrix. The object of study was the structure of Pd nanocrystals and interaction between Pd and carbon matrix interface. In the research...
If a cold-cathode ionization gauge is operated in a gas atmosphere with a high content of hydrocarbons at high pressures, the pressure reading of the gauge is disturbed by the contamination after a certain time of operation. Since in the most cases it is not possible to eliminate these disturbing residual gas components, one has to demand that the measuring process may not be substantially influenced...
Unusual properties of the diluted nitrides A III B V –N make them very attractive in the point of view of fundamental investigations and practical applications. This work presents the growth characteristics and properties of the undoped GaAs 1−x N x /GaAs heterostructures obtained by the atmospheric pressure metal organic vapour phase epitaxy (APMOVPE). The properties...
The exact magnetization pattern of magnetic films close to a spin-reorientation transition is difficult to analyze due to the intrinsically three-dimensional (3d) variation of the orientation of the local magnetization. We present a technique how this can be performed, based on the analysis of high quality 2d polarization maps from a single scanning electron microscope with polarization analysis (SEMPA)...
For the future project the Facility for Antiproton and Ion Research (FAIR) at GSI, an accelerator system with a base pressure of 10 −10 Pa is required. The low pressure is needed to reduce the charge exchange rate between the accelerated ions and the residual gas molecules and therefore to increase the ion beam lifetime. Among the different measures undertaken to upgrade the existing UHV system,...
For conventional (single-flow) turbomolecular pumps (TPs) the central disc area of the inlet side of the compressor turbine is blind for pumping and may be utilized otherwise. The design feature of the new Ring TP displays a central opening of the TP all along the axis, where care is taken to prevent coupling between the vacuum areas on both sides of the compressor turbine. The axial opening can be...
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