Materials Literature
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We report on the first molecular beam epitaxial (MBE) growth of CdZnS on (100) GaAs substrates using elemental Zn, Cd, and S sources. Single crystal cubic CdZnS layers lattice matched to GaAs have been successfully prepared. The competition in incorporation between Cd and Zn under different sulfur flux conditions is i…
X-ray absorption fine structure (XAFS) measurements of mixed salts ${\mathrm{Rb}}_{\mathit{x}}$${\mathrm{K}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Br and ${\mathrm{RbBr}}_{\mathit{y}}$${\mathrm{Cl}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$ at their congruent melting points compositions reveal that their actual structure b…
Evidence of a magnetic-field-induced isotropic-nematic phase transition is presented for a colloidal suspension of monodisperse fd virus, a semiflexible particle with a length-to-diameter ratio of \ensuremath{\sim}140. The dynamics of the phase transition are slow enough to study the unstable portion of the phase diag…
Photoemission and x-ray absorption spectroscopy show that both the conduction and valence bands of porous silicon are shifted relative to the bands for bulk silicon, as expected in the quantum confinement model for the optical properties of porous silicon. The shift in the valence band is larger than the shift in the…
A series of III-V-based magnetic semiconductor heterostructures, p-type (In,Mn)As/(Ga,Al)Sb, has been grown by molecular beam epitaxy. Studies on magnetotransport and magneto-optical properties show that perpendicular ferromagnetic order occurs in the heterostructures with thin (In,Mn)As layers. The origin is discusse…
We have studied, via x-ray scattering, the nematic to smectic-A (NA) translational ordering of the liquid-crystal--forming compound octylcyanobiphenyl (8CB) incorporated into the pores of a silica aerogel. We find that the aerogel dramatically alters 8CB phase behavior, eliminating the NA transition found at T=${\math…
The size dependence of the contribution to the excitonic dephasing rate in semiconductor nanocrystals is clarified for various electron-phonon coupling mechanisms. On the basis of these dependencies, the commonly observed linearly temperature-dependent term of the excitonic dephasing rate and the proportionality of it…
Abstract Blends of poly(vinyl chloride) (PVC) and epoxidized natural rubber (ENR) were prepared by melt‐blending and studied using a Monsanto rheometer, infrared spectrophotometer, and dynamic mechanical analyzer. The PVC/ENR blends were found to be self‐crosslinkable, but immiscible at 25/75, 50/50, and 75/25 blend r…
静的破砕剤は, 岩盤やコンクリートの解体に広く用いられているが, 最も重要なのは, ボーリング孔中の膨張圧の挙動をいかに正確に把握するかである. 本研究ではまず, ボーリング孔中の膨張圧の直接的測定方法を開発し, それを用いて膨張圧に及ぼす各種要因とそれらに対する膨張圧の挙動について検討を行った. その結果, 1) 膨張圧はあまり拘束度の影響を受けず, 2) 液圧的伝播をする, 3) 周囲の温度の影響が顕著であるが, 温度が変化しても水和率が同じであれば, 膨張圧は同じである等のことを明らかにした.
The dynamics and spectroscopy of silicon nanocrystals that emit at visible wavelengths were analyzed. Size-selective precipitation and size-exclusion chromatography cleanly separate the silicon nanocrystals from larger crystallites and aggregates and provide direct evidence for quantum confinement in luminescence. Mea…
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…