Materials Literature
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By using the optical spectral parameters of (NiF6)3− clusters in KMgF3:Ni3+ and CsCaF3:Ni3+ crystals estimated from the observed values in pure K3NiF6 crystal, the electron paramagnetic resonance (EPR) g factors for KMgF3:Ni3+ and CsCaF3:Ni3+ are calculated from the second-order perturbation formula (with the high-spi…
Austenitic 349 stainless steel was nitrided in an NH3 plasma. A low interfacial contact resistance was obtained with the nitrided steel. Glancing angle X-ray diffraction suggests that the nitrided layer is very thin and possibly amorphous. X-ray photoelectron spectroscopy (XPS) studies show that the nitrided layer is…
A polyoxometalate [Co(phen)3][Co(en)3][Co(en)2(H2O)2][Co(en)2]0.5[O40(VIVO)2] · 6H2O (1) (en = ethylenediamine, phen = 1,10-phenanthroline) has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, electron paramagnetic resonance, X-ray photoelectron spectroscopy, elem…
The origin of the incommensurability in the crystallographic shear (CS) structure of the ferri-Manganite (Sr 0.61 Pb 0.18 )(Fe 0.75 Mn 0.25 )O 2.29, related to the cation deficient perovskite, has been determined by careful analysis of the boundaries between the two variants constituting the phasoid. High Resolution E…
Nanostructured thin silicon-based films have been deposited using the hot-wire chemical vapour deposition (HWCVD) technique at the University of the Western Cape. A variety of techniques including optical and infrared spectroscopy, Raman scattering spectroscopy, X-rays diffraction (XRD) and transmission electron micro…
During centrifugal casting, when a mould is rotated at very low and very high speeds, defects are found in the final castings. Obtaining the critical speed for sound castings should not be a matter of guess or based on experience. The defects in the casting are mainly due to the behaviour of the molten metal during te…
To understand the effects of picolinamide-like ligands on reaction equilibrium, a series of picolinamide derivatives were synthesized and the interactions between the diperoxovanadate complex [OV(O2)2L]− (L = D2O or HOD, abbr. bpV) and picolinamide ligands in solution were explored using multinuclear (1H, 13C, and 51V…
We have developed and refined a chemical vapour deposition method to synthesise nanotubes using liquid petroleum gasasthe carbonsource. The nanotubes were thoroughly characterised by scanning electron microscopy, transmission electron microscopyX-ray diffraction and thermogravimetric analysis. The protocol to grow nan…
Based on the transformation optics, a general method of light-behavior remote control is proposed. From this method, the important coefficients of a cavity, i.e. the quality factor Q and the resonant frequency ?0 could be tuned in a wide range by a transformation optical device in distance, so that the light behavior…
Although switching techniques based on charge injection in silicon have progressed greatly in recent years, switching energies are still above 10 fJ/bit, which is considered the threshold for practical implementation in on-chip optical interconnects. This is due primarily to silicon's relatively weak electro-optic res…
The spectral properties of a tautomeric Schiff base containing aza-15-crown-5 moiety, namely N-((4-methylnaphthalen-1-yl)methylene)-4-(1,4,7,10-tetraoxa-13-azacyclopentadecan-13-yl)aniline on addition of alkali and alkaline earth metal ions were investigated. The newly synthesized ligand exhibited very interesting col…
Fatigue is one of the most important aging effects of power plant components. Information about fatigue helps in assessing structural degradation of the component and so assists in planning in-service inspection and maintenance. In this paper, we present a computation method that can be used to estimate the working li…
In this research, effects of six different strips size (2, 4, 6, 8, 10 and 12 mm thick respectively) and six different coating thicknesses on the fluidity of A356 aluminium alloy in lost foam casting (LFC) process were investigated. It was found that, in each mould, as the strip thickness increases, fluidity length in…
The solidification paths for UFeB4, UFe3B2 and UFe4B, ternary compounds, situated along the U:(Fe,B) = 1:5 line in the B-Fe-U phase diagram, are proposed based on x-ray powder diffraction measurements, differential thermal analysis, heating curves and scanning electron microscopy observations complemented with energy…
The magnetic properties of the diluted magnetic semiconductor Ga1-xMnxAs are studied within the dynamical cluster approximation. We use the k x p Hamiltonian to describe the electronic structure of GaAs with spin-orbit coupling and strain effects. We show that nonlocal effects are essential for explaining the experime…
O trabalho aborda um estudo comparativo entre a técnica de Cromatografia a Líquido de Alta Eficiência e a técnica de Calorimetria Exploratória Diferencial, visando avaliar a aplicação desta para a determinação direta da pureza de fármacos candidatos a materiais de referência certificados.
The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti ions are investigated. It is shown, that the ZnAl(2)S(4):Ti spinel-type crystals exhibit luminescence in the IR spectral range 0.8-1.4 µm. The observed spectroscopic characteristics are assigned to the emission bands arisin…
Abstract To optimize the primary drying step of freeze‐drying processes, it is very important to control morphological parameters of the frozen matrix. A mathematical model that simulates temperature profiles during freezing process of standard pharmaceutical formulations was set up and the ice crystal mean sizes were…
Highly dispersed and uniform Fe(2)O(3) nanoparticles (NPs) have been incorporated into the pore channels of SBA-15 mesoporous silica thin films (MSTFs). And such Fe(2)O(3) NPs incorporated MSTFs did not show detectable nonlinear optical (NLO) signals at off-resonance wavelength 1064 nm by Z-scan technique. However aft…
The zirconia nanopowder stabilized with 2.5 mol% Y(2)O(3) and doped with 18 mol% TiO(2) (Zr(Y,Ti)O(2)) was homogenized with 5.2 wt% multiwall carbon nanotubes (MWCNT) through colloidal processing. The resultant mixture was heat-treated for 2 h at 1200 degrees C in vacuum under a pressure of 5 x 10(-4) mbar. The micros…