Materials Literature
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Indium oxide (InOx) films with a thickness of 100–500 nm were prepared by dc magnetron sputtering onto Corning 7059 glass substrates. The as-deposited films were microcrystalline as revealed by x-ray diffraction analysis. The conductivity of the as-deposited films was of the order of 10−3–10−2 Ω−1 cm−1 and increased u…
To understand the nature of Ag-rich chalcogenide glasses, the optical, electrical, and structural properties of evaporated amorphous (Ge0.3S0.7)100−xAgx and (Ge0.3Se0.7)100−yAgy films have been examined and compared with each other over a wide compositional range in Ag content. The maximum Ag content for the amorphous…
We show for what is believed to be the first time that it is possible to generate 10,000 rapid write, read, and erase cycles optically in an azobenzene sidechain liquid-crystalline polyester. We do this by exposing the film alternately to visible light from an argon laser at 488 nm and ultraviolet light from a krypton…
Superconductivity has been observed in single-crystalline Sr 1- x La x TiO 3 samples for x = 0.001 and 0.009, which were previously classified as nonsuperconducting semiconductors. The relation between the critical temperature T c and the carrier density n is comparable with those previously observed in Nb-doped or re…
CdS thin films with various grain sizes were produced by rf sputtering and in situ postannealing processes. For a series of annealing time intervals, the average grain sizes of an as-deposited thin film with thickness ∼4000 Å were found to vary from ∼280 to ∼1500 Å. Three bands located in the green, yellow, and red re…
α,α′-dimethyl substituted oligothiophenes with increasing chain length (from the dimer up to the hexamer) were recently synthesized by chemical methods. In this paper we have investigated the vibrational Fourier transform-IR and Fourier transform-Raman spectra of solid α,α′-dimethyl substituted oligothiophenes in the…
We show the alignment of defect dipoles along the direction of the spontaneous polarization in polycrystalline Pb(Zr,Ti)O3 and BaTiO3 ferroelectric ceramics using electron paramagnetic resonance (EPR). The alignment is demonstrated via orientation dependent paramagnetic centers in the polycrystalline materials and com…
We have carried out a study of the photoluminescence properties of silicon-rich silica. A series of films grown using plasma enhanced chemical vapor deposition over a range of growth conditions were annealed under argon at selected temperatures. Photoluminescence spectra were measured for each film at room temperature…
Differential scanning calorimetry, Raman scattering, optical absorption, and upconversion of infrared to green luminescence have been studied for Er3+-doped lead-germanate glass 55GeO2⋅20PbO⋅10BaO⋅10ZnO⋅5K2O (GPBZK) and lead-tellurium-germanate glass 30GeO2⋅30PbO⋅30TeO2⋅10CaO (GPTC). Judd–Ofelt intensity parameters of…
The luminescence mechanism in a-C:H is described as a modification of the band tail luminescence in hydrogenated amorphous Si. The tail states of a-C:H are formed from clusters of ${\mathit{sp}}^{2}$ sites and luminescence occurs by recombination within each cluster. The paramagnetic defects are confirmed as the nonra…
β-Ga2O3 contains two crystallographically different Ga atoms in the asymmetric unit, one with tetrahedral and the other with octahedral coordination geometry. The Ga-O distances are in the range 1.833 (1)–1.863 (2) Å within the tetrahedra, but are longer within the octahedra [1.935 (2)–2.074 (1) Å]. The O atoms have a…
We use photoluminescence excitation and fluorescence line narrowing spectroscopies to examine structure observed in the band-edge absorption feature of CdSe quantum dots. We study eight samples ranging from \ensuremath{\sim}15 to \ensuremath{\sim}50 \AA{} in radius to probe the size dependence of this structure. We co…
We use photoluminescence excitation to study the electronic spectrum of CdSe quantum dots ranging from \ensuremath{\sim}12 to \ensuremath{\sim}53 \AA{} in radius. We follow the size evolution of ten quantum dot absorption features. Comparison of the spectra with theoretical predictions allows us to confidently assign…
γ-Irradiation of poly(tetrafluoroethylene) (PTFE) in the presence of air results in degradation of polymer chains by insertion of oxygen. At first, in the low-dose range below 400 kGy, a rise in crystallinity can be observed due to main chain scission in the amorphous part of the macromolecules. Dose increase up to ap…
The effects of silica, mullite, α-alumina and γ on the nonoxidative thermal degradation of poly(vinyl butyral) are described. To varying degrees, all of the inorganic oxides catalyzed reactions that produced butanal. Other significant products included: water, butenal, acetic acid, and alkyl aromatics. Two distinct ev…
A comprehensive kinetic model for a semibatch direct esterification reactor has been developed. The solid-liquid equilibirium of terephthalic acid was considered in the modeling. Effects of the monomer feed ratio, reaction temperatures, and oligomer addition on the conversion, degree of polymerization, and the formati…
An attempt was made to modify the properties of poly(butylene terephthalate) (PBT) by blending it with polyamide-6 (PA-6). Since PBT and PA-6 are incompatible, epoxy resin was used as a compatibilizer to form an alloy. Alloys of PBT and PA-6 with varying amounts (0–12%) of epoxy resin E-44 were prepared by melt blendi…
To improve the physical properties of starch-filled polyolefin, starch was modified into more hydrophobic material by the introduction of cholesterol unit, and the different starch-compositioned high-density polyethlene (HDPE) films were prepared with addition of either native starch or modified starch to compare thei…
Silk fibers were graft-copolymerized with methacrylamide (MAA) and 2-hydroxyethyl methacrylate (HEMA) in aqueous media, using a chemical redox system as an initiator. High weight gains (300%) were obtained with both monomers, the weight gain being linearly related to the amount of monomer contained in the reaction sys…
The thermal behavior in argon of homogeneously synthesized cellulose p-toluenesulfonates (tosylates) with a degree of substitution (DS) ranging from 0.4 to 2.3 was studied by means of thermogravimetry and derivative thermogravimetry from ambient temperature up to 500°C. For comparison, the thermal behavior of the star…