Materials Literature
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The electrical properties of nitrogen-containing amorphous hydrogenated carbon layers are investigated. The nitrogen concentration was between 0 and 6 at%. The electrical conductivity is found to increase with the nitrogen content. The temperature dependent conductivity in the temperature range between 150 and 350 K c…
Push-pull fatigue deformation of 99.999 Al polycrystals is performed at room temperature at strain amplitudes in the range (25 to 800) × 10−6. Variations of the stress σ, energy loss ΔE, and ultrasonic attenuation Δα versus cycle number N under various push-pull fatigue strain amplitude εa are measured systematically,…
The alloys with composition around Sm11.5Co58.4Fe22.5Cu5.3Zr2.4 (at%) present hard magnet properties when their microstructure consists of a network of cells based on Sm2(Co, Fe)17, limited by boundaries based on Sm(Co, Cu)5 and cut by platelets based on (Sm, Zr)Co3. The genesis of this microstructure is studied by tr…
Dimolybdenum dithallium diphosphate, Tl 2 Mo 2 P 2 O 11 , is isotypic with K 2 Mo 2 P 2 O 11 . Its framework is built from the original Mo 2 P 2 O 15 unit, formed by one Mo 2 O 11 group sharing four of its corners with two PO 4 tetrahedra, leading to [Mo 2 P 2 O 13 ]∞ chains running along c. The [Mo 2 P 2 O 11 ]∞ fram…
Pulsed laser ablation from oxide surfaces in hydrogen atmosphere is shown to be a powerful new method for deposition of high quality metal films. Specifically, the cases of ablation from CuO and α-Fe2O3 are studied. By examining the effects of hydrogen pressure, laser energy density, and the substrate temperature on t…
Abstract This work deals with the heat treatment of fibers and nonoriented specimens made of the thermotropic liquid crystalline polymer Vectra A900 in the light of tensile properties and DSC measurements. In calorimetric measurements, there seem to be some differences in the effects of the treatment between macroscop…
We utilize a geometric argument to determine the effects of boundary scattering on the carrier mean free path in samples of various cross sections. Analytic expressions for samples with rectangular and circular cross sections are obtained. We also outline a method for incorporating these results into calculations of t…
The mechanisms responsible for the core-level binding-energy (BE) shifts that occur for surface and bulk atoms of the Al(100) surface are identified and characterized through theoretical analyses of the surface electronic structure. Two initial-state mechanisms are shown to be responsible for the shifts of the surface…
An EL5-like trap in metalorganic vapor-phase epitaxially grown GaAs:Sb has been detected by deep-level transient spectroscopy. The trap behavior has been investigated by changing the growth conditions—the V/III ratio and the level of isoelectronic doping with Sb. It has been found that the activation energy of the EL5…
A method for solving wave propagation problems in bounded media that operates entirely in wave-vector space is presented. No boundary conditions are used in the solution in contrast to the real-space method. The transmission/reflection problem of an electromagnetic wave on a dielectric half-space is solved as an illus…
Passivating films were grown on gallium arsenide by direct nitridation with hydrazine at 300–400 °C. Auger electron spectroscopy and x-ray photoelectron spectroscopy analysis show that the films are primarily gallium nitride with an oxide impurity. The oxide content is a function of the surface pretreatment, reaction…
We review mixing and phase separation (demixing) in mixtures of low molecular weight liquid crystals (LCs) and organic matrices, with emphasis on aspects relevant to the formation of polymer-dispersed liquid crystal films. These films, which contain a myriad of micron-sized LC droplets, are of interest because of thei…
A formalism is presented for determining the magnetoelastic (ME) coefficients of tetragonally distorted surfaces and thin films. The equation of motion of the magnetization is determined from free-energy-density expressions containing terms for crystalline and shape anisotropy, ME anisotropy, and applied field. Canoni…
A symmetric phase-field model is used to study directional solidification in two and three dimensions. Numerical evidence of tip-splitting, breathing modes, solitary modes, and other non-steady-state behavior is seen in 2D. A simple model for the breathing modes is proposed. Finally, 3D simulations indicate a hexagona…
The dc electrical conductivity (\ensuremath{\sigma}) of activated carbon fibers (ACF's) heat treated at temperatures (${\mathit{T}}_{\mathrm{HT}}$) ranging from 300 to 2500 \ifmmode^\circ\else\textdegree\fi{}C has been measured from 4.2 K to room temperature, and the magnetoresistance of these same fibers has been mea…
Using the x-ray excited optical luminescence technique, we have investigated the soft x-ray induced photoluminescence of porous silicon in the optical region (200–900 nm) and the Si K-edge x-ray absorption fine structures of porous silicon in the near edge region. It is found that while porous silicon prepared at low…
The predicted amino acid sequence encoded by the open reading frame 221 (orf221) of bacteriophage lambda exhibited a high degree of similarity to the catalytic subunits of a variety of protein serine/threonine phosphatases belonging to PP1, PP2A, and PP2B groups. Cloning and expression of the orf221 gene in Escherichi…
A method is proposed to control the wavelength of visible photoluminescence (PL) from porous silicon (PS). This is based on the post-anodization illumination technique which employs a filtered light with various maximum cutoff photon energies. As the illumination time increases, the PL spectra shift toward the higher…
Abstract Mechanical and Morphological properties of polyamide‐6/ABS blend systems, compatibilized by styrene‐maleic anhydride (SMA) copolymer, have been studied. The strength, modulus, and impact properties improved upon the addition of SMA. Morphological studies, using small angle light scattering, polarizing microsc…
Copper films have been deposited by low pressure chemical vapor deposition from mixtures of the Cu+1 precursor copper hexafluoroacetylacetonate vinyltrimethylsilane and water vapor. The addition of water vapor at the optimum concentration more than doubles the deposition rate and substantially reduces the nucleation t…