Materials Literature
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We have grown amorphous hydrogenated boron carbide thin films on a cathode substrate by rf plasma decomposition of diborane and methane. The chemical composition, infrared absorption, optical absorption, microhardness, and adhesion of these thin films were measured. As a function of increasing diborane concentration i…
PART 1 RADIOGRAPHY and MATHEMATICS: Principles of Radiography. Geometric Radiography. The Inverse Square Law. The Exponential Law. PART 2 GENERAL PHYSICS: Laws of Physics (Classical). Units of Measurement. Experimentation and Statistics. Heat. Electrostatics. Electricity (DC). Magnetism. Electromagnetism. Electromagne…
Tunable room-temperature electroluminescence, photocurrent, and photoluminescence in the near infrared (λ∼1.3 μm) has been observed from Ge/Si/Ge/Si1−xGex quantum-well (QW) diodes grown by molecular-beam epitaxy. The QWs are grown on a p+-doped 〈100〉-Si substrate and consist of two thin Ge wells separated by a thicker…
We calculate numerically the full Floquet-Bloch stability spectrum of cellular array structures in a symmetric model of directional solidification. Our results demonstrate that crystalline anisotropy critically influences the stability of these structures. Without anisotropy, the stability balloon of cells in the plan…
We have deposited boronated highly tetrahedral amorphous carbon (ta-C:B) films with low stress using a filtered cathodic vacuum arc. The sp3 fraction, hardness, and resistivity were measured as a function of the ion energy and were found to reach a maximum above 50 eV for B concentrations of 2% and 4%. The most signif…
The 3p absorption spectrum of over the and resonance regions is theoretically studied for the first time. The calculations were performed within the `spin-polarized' random-phase approximation with exchange. The ordering of these resonances is found to be opposite to that in Cr, and . As a result, the 3p absorption of…
We study the effect of DC electric field application on a ceramic by impedance spectroscopy and depolarization current measurements. The results indicate the onset of a true ferroelectric phase, characterized by long-range order, instead of a glassy one. The `freezing' temperature deduced from the Vogel - Fulcher rela…
Magnetic properties of ${\mathrm{Sn}}_{1\ensuremath{-}x}{\mathrm{Gd}}_{x}\mathrm{Te}$ semimagnetic semiconductor reveal a strong dependence of antiferromagnetic exchange coupling between Gd spins on the concentration of carriers. We present a model explaining consistently both magnetic and transport properties of SnGd…
The growth of epitaxial rare-earth-transition-metal thin films is reported by magnetron sputtering on single-crystal MgO substrates. The use of epitaxial W buffer layers demonstrates a general approach to control the phase and orientation of the films. Structure and magnetism results for SmFe12(001) on W(100) and magn…
Anisotropic local structure has been observed around both the Fe and Ba ions in the amorphous precursor to Ba-hexaferrite thin films, using polarization-dependent extended x-ray-absorption fine structure. This anisotropic local structure, consisting mainly of a network of Fe-O octahedra, determines the orientation of…
Single bubble sonoluminescence is understood in terms of a shock focusing towards the bubble center. We present a mechanism for significantly enhancing the effect of shock focusing, arising from the storage of energy in the acoustic modes of the gas. The modes with strongest coupling are not spherically symmetric. The…
Combined partial discharge detection and video monitoring of the tree growth have shown a strong correlation between the partial discharge activity and the spatial and temporal development of electrical tree growth in CY1311 epoxy resin. CCD imaging of the spatial distribution of light emitted, due to partial discharg…
Quantum confinement effects in Ge nanocrystals in the size range 26–130 Å have been investigated both on the electronic joint density of states and Raman spectra. The high degree of crystallinity of the particles as well as the minimized interaction with the matrix allow detection of shift and broadening of the TO Ram…
Lithium ferrite nanocrystallites ranging from several nanometres to several hundreds of nanometres in size have been prepared by the polyethylene glycol gel method. These nanocrystallites were identified as pure lithium ferrite by x-ray diffraction analysis. Their magnetization and de-magnetization were measured by us…
The reduction of copper oxide thin films by a hydrogen plasma generated by an atmospheric-pressure glow (APG) discharge was investigated. The copper oxide films were prepared by heating the sputtered copper films to C in the air (heat-formed copper oxide) or by sputtering (sputtered copper oxide). Both films were comp…
We report a new photophysical phenomenon in which 1.06 \ensuremath{\mu}m pulses from a Q-switched Nd:YAG laser induce crystallization in supersaturated solutions of urea in water. Because the solutions are transparent at the incident wavelength, a photochemical mechanism is unlikely. The needle-shaped crystals that in…
We report the degree to which the resonances associated with metal island films can be used to enhance the sensitivity of very thin semiconductor photodetectors. The island films can couple incident light into the waveguide modes of the detector, resulting in increased absorption. To characterize the coupling, silver-…
The birefringence of planar 8OCB samples has been measured as a function of temperature at thicknesses decreasing from 7.2 to 2.6 μm. The first curve (7.2 μm) is perfectly superimposable to the result of conoscopic measurements done with a 100 μm homeotropic uniaxial sample, from a minimum of 0.08 close to the isotrop…
Different emulsion polymerization processes allowed variation in the microstructure of composite natural rubber (NR)-based latex particles. A prevulcanized and a not-crosslinked natural rubber latex were coated with a shell of crosslinked poly(methyl methacrylate) (PMMA) or polystyrene (PS). The bipolar redox initiati…
We have prepared nanosized hairy grains by grafting long polydimethylsiloxane chains onto silica particles of radius ≈ 15 nm. The synthesis method allows the particles to keep in truly stable suspension at any stage of their preparation. In dilute suspension, these hairy grains behave as repulsive soft spheres. Above…