Materials Literature
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Summary Single crystals of zircon doped with 239 Pu, up to 2 mm in size, were grown for the first time ever, using a Li-Mo flux. The crystals were transparent and free of inclusions of separated Pu phases. The zircon crystals were studied using optical and scanning electron microscopy, the electron microprobe, and cat…
A GaN-based blue diode laser is employed for laser absorption spectroscopy in an aluminum hollow cathode glow discharge plasma. A Littrow grating stabilized external resonator is used for tuning the wavelength of laser emission. Scanning the wavelength of the laser probes the absorption profile of aluminum transitions…
Experimental results are reported which show a strong evidence of energy transfer between Ho3+ ions in a fluoroindate glass excited by a pulsed laser operating at 640 nm. We identified the origin of the blue and green upconverted fluorescence observed as being due to a Ho3+–Ho3+ pair interaction process. The dynamics…
We realized what we believe is a new phase-shifting scatterplate interferometer by exploiting the polarization characteristics of a birefringent scatterplate. The common-path design of the interferometer reduces its sensitivity to environmental effects, and phase shifting allows quick and accurate quantitative measure…
The synthesis, characterization, and mesomorphic properties of a new type of heteronuclear compounds derived from pyrimidine as core group are reported. These compounds were prepared by condensation reactions of appropriate acetophenones and benzonitriles in the presence of trifluoromethanesulphonic anhydride. They we…
Although it has been well accepted that F-Al linkages dominate in F-bearing alkali aluminosilicate glasses, the possibility of F-Si linkages remains unresolved. Recent 19 F NMR results have been interpreted as indicative of not only the presence of the Al-F-Na(n) linkages but also of the presence of Si-F-Na(n) linkage…
The mechanism of the carbon nanotube (CNT) formation and its graphitization has not been well understood and is still under controversy. The authors have been studying a new process to form CNTs, where polyyne-containing carbons are heated and irradiated by an electron beam in a transmission electron microscope (TEM).…
Strong electroluminescence was observed in a CdTe nanoparticle light-emitting diode that was fabricated by layer-by-layer assembly of poly(p-phenylenevinylene) and CdTe nanoparticles. The turn-on voltage for the electroluminescence is 4.0 V. The electroluminescence is exclusively from CdTe nanoparticles, with a 30 nm…
Multiphonon Raman scattering in semiconductor nanocrystals is treated taking into account both adiabatic and nonadiabatic phonon-assisted optical transitions. Because phonons of various symmetries are involved in scattering processes, there is a considerable enhancement of intensities of multiphonon peaks in nanocryst…
The relation between electrical and structural properties of indium tin oxide (ITO) films prepared by pulsed laser deposition with and without in situ laser irradiation is examined. The residual stresses of the films were estimated from x-ray diffraction patterns measured by grazing-incidence asymmetric Bragg and graz…
Amorphous silicon nanocolumns, square nanospirals, and multilayer spiral/column rods are fabricated on bare Si substrates and monolayer colloid substrates by glancing angle deposition. The grown films are studied by scanning electron microscopy and transmission electron microscopy. The size of the deposited Si columns…
The different magnetic and crystallographic structures in the series of ${\mathrm{Tb}}_{5}({\mathrm{Si}}_{x}{\mathrm{Ge}}_{1\ensuremath{-}x}{)}_{4}$ compounds have been studied by means of macroscopic (ac magnetic susceptibility, linear thermal expansion, and resistivity) and microscopic neutron powder diffraction exp…
The optical constants and dielectric functions of a series of samples of glassy carbon subjected to a heat treatment from 1000°C to 3000°C have been evaluated in the spectral region of 1.5–13.8 eV. In the region of 1.5–5.0 eV the method of spectroscopic ellipsometry and multiangle reflectivity with p-polarized light w…
The transmission and reflection of light are considered in the case of its normal incidence on a layer of a periodically nonuniform medium possessing dielectric and magnetic helicities, with the axes of electrical and magnetic permittivities being rotated relative to each other. A simple algorithm for constructing the…
Anodic polarization studies have been conducted on mild steel in urea ammonium nitrate (UAN) fertilizer solutions comprising 31 wt% urea ([NH2]2CO), 39 wt% ammonium nitrate (NH4NO3), and 30 wt% H2O, with a total N content of 28 wt% (UAN 28-0-0). It was determined that mild steel can spontaneously exhibit either active…
Abstract The crystal structure of the globular organic molecule R-thiocamphor (C 10 H 16 S) has been studied at ambient and low temperatures by high resolution powder X-ray diffraction using synchrotron radiation. At around 260 K thiocamphor transforms on cooling to an ordered orthorhombic structure from the orientati…
Abstract The materials essential to the modern military helicopter are reviewed. In addition to materials of high specific strength and stiffness, such as aluminium alloys and fibre-reinforced composites, more specialized materials are also considered. These include materials for armour protection and signature reduct…
The effect of Cr, Al, and Si on the anodic polarization characteristics of Fe-Cr alloys was studied, with Cr content ranging from 10% to 18% in sulfuric acid (H2SO4) and sodium chloride (NaCl) aqueous solutions. It was shown that the effect of Al depended on Cr content while the beneficial effect of Si was found to be…
A generalization of the function of influence of a unit heat source to the displacements is suggested for the boundary value problems in the dynamical uncoupled thermoelasticity. This generalization is a convolution over time and bulk of two influence functions. One of them is a Green's function for the heat conductio…
Abstract The structure and the mechanical properties of blends of an amorphous polyamide (PA) and a thermotropic copoly(ester‐amide) (VB) obtained both by direct injection molding (DI) and also by extrusion and subsequent injection molding (EI) have been studied. Besides the usual fibrillar morphology of the skin, fib…