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Carbon nanotubes (CNTs) were introduced into carbon fiber felts by electrophoretic deposition (EPD) and then pyrocarbon (PyC) was infiltrated in the felts by thermal gradient chemical vapor infiltration using methane as precursor to prepare carbon nanotube (CNT) reinforced carbon/carbon composites (CNT-C/C composites). The effects of CNTs by EPD on microstructure, mechanical and thermal properties...
A novel MoSi 2 –Al 2 O 3 solar selective absorbing coating deposited on stainless steel (SS) substrate by magnetron sputtering is reported. The effects of the HMVF and LMVF absorption layers thickness and metal volume fraction on optical properties of the coatings are investigated. As the thickness or metal volume fraction of the HMVF or LMVF layers increases, it is found that...
The aim of this work is to highlight the influence of the material constructing the anode in wire-to-cylinder negative corona discharge. A numerical simulation is presented where a plasma of pure oxygen has been considered. Three materials (stainless steel, copper, aluminum) are tested. The study is carried at atmospheric pressure and for different temperatures and voltages. The numerical results...
An extended Monte Carlo method based numerical model of the hot cavity ion source is presented. Not only the radioactive decay and delays due to the sticking of atoms to hot walls are taken into account, but also (i) delays due to the diffusion of nuclides, (ii) contributions from electron impact ionization, (iii) calculations of ion release curves and (iv) the case of hemispherical cavities are implemented...
A void free Cu 2 ZnSnS 4 (CZTS) thin films were grown on Mo-coated glass substrates by using sulfurization of sputtered stack metallic precursor at 580 °C in (N 2 + H 2 S) atmosphere for different sulfurization times ranging from 60 min to 180 min. The effects of sulfurization time on the structural, morphological, chemical and optical properties of the sulfurized...
This paper studies ozone synthesis in a dielectric barrier discharge reactor powered by a high voltage positive pulse power supply with a short duration (∼400 ns). The influence of ozone concentration on the peak pulsed voltage (4.8 kV–20 kV), the pulse repetition rate (50 pps–300 pps) and gas flow rate is investigated. It is shown that ozone concentration reaches its maximum of 74.1 g/m 3 ...
Thermal transpiration effects are commonly encountered in low pressure measurements with capacitance diaphragm gauges. They arise from the temperature difference between the measurement volume and the temperature stabilised manometer. Several approaches have been proposed to correct for the pressure difference, but surface and geometric effects usually require that the correction is determined for...
Application of vacuum insulation panel (VIP) is becoming more practical to reduce the thermal energy loss and to reduce CO 2 emission. Outstanding insulation performance and extended service life are the two critical factors in the VIP engineering. Thermal insulation performance of a VIP is degraded with time due to gradual increase of pressure in the VIP. Keeping the effectively low pressure...
Rutherford Backscattering Spectroscopy measurements were carried out on p-type silicon prior to and after metal diffusion in order to determine the amount of diffused metal. The metals used were gold, platinum, erbium and niobium. The amount of the diffused metals was estimated by using the peak heights of the spectra. In all cases the heights become smaller after diffusion to show a reduction in...
We have developed hybrid organic/inorganic heterojunction based on PVK:PcH 2 :C343:C 60 nanocomposite spin coated on porous silicon (π-Si) substrate, to investigate the efficiency of the combination of these materials as donor–acceptor (D/A) systems for photovoltaic applications. PcH 2 and C343 organic dyes were incorporated into the matrix of PVK to enhance its optical absorption...
Using first-principles method based on density functional theory, we have comparatively studied surface relaxation, surface energy, and electronic structure of the low-index surfaces (001), (110), and (111) of c-BN. The calculated surface energy indicated c-BN (110) was the most stable surface over the range of nitrogen chemical potential. It was consistent with the relaxation result that (110) surface...
The influence of the partial substitution of Si by Ge (6 at.%) on the structure, crystallization kinetics and magnetic properties of Finemet-type alloys were studied by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimeter (DSC) and room-temperature hysteresis loops measurements. Amorphous ribbons were heat treated at different temperatures for...
Vanadium oxide (VOx) thin films were deposited on glass substrates at room temperature by pulsed DC reactive magnetron sputtering. The effects of the duty cycle of the pulsed power and oxygen flow on the surface morphology, deposition rate, composition and electrical properties of VOx films were systematically investigated. Experimental results revealed that decreasing the duty cycle or increasing...
In recent years, NiTi shape memory alloys (SMA) thin films have been widely used as promising high-performance materials in the field of biomedical and microelectromechanical (MEMS) systems. However, there are still important problems such as their unsatisfactory mechanical and tribological properties including a limited hardness and wear resistance. This study aimed at deposition of layered composite...
The angular (φ-) dependences of the yields of scattered ions and neutrals were measured when 8–80 keV Ar 8+ ions were obliquely incident on the single-crystalline ZnO (0001) and (0001¯) surfaces at small incidence angles of ψ = 5, 7, and 9° measured relative to the plane of the surface. The φ dependences of the yields had a peak near the specular reflection angle that is φ ∼ 2ψ. The maximum...
The Facility for Rare Isotope Beams (FRIB) is a superconducting heavy-ion linear accelerator that is to produce rare isotopes far from stability for low energy nuclear science. In order to achieve this, its driver linac needs to achieve a very high beam current (up to 400 kW beam power), and this requirement makes vacuum levels of critical importance. Vacuum calculations have been carried out to verify...
Grain size of vanadium dioxide (VO 2 ) films or isolated particles is known to play an important role in the modulation of temperature dependence of the hysteresis width in semiconductor to metal transition. In order to investigate the effect of grain size on the hysteresis width, we prepare a range of VO 2 films consisting of spheroidal nanoparticles whose mean size was hugely modulated...
Al, La doped ZnO nano particles were prepared through sol–gel method. The prepared ZnO: (Al, La) was coated on cotton fabric, forming a thin film to reduce infrared emissivity of the cotton fabric. Effects of Al contents on microstructure, infrared emissivity and infrared stealth of ZnO: (Al, La) coated fabrics were investigated by XRD, SEM, ICP, IR_2 dual-band emissivity measuring instrument and...
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