Materials Literature
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The authors model the optical properties of metallic quantum wells with thicknesses in the range of a few nanometers. A simple picture that includes only single electron transitions predicts strong absorption lines at frequencies associated with allowed interband transitions. This strong absorption feature can be in t…
Abstract An equilibrium theory is proposed for crystallization of (A, B) binary copolymers whose comonomeric unit sequences are statistically described by conditional pair probabilities P AA , P AB , P BA , and P BB . These are linked to the product of the reactivity ratios by r = r A r B = (P AA P BB )/(P AB P BA ) .…
Abstract Dissolution of phosphate rock (PR) in soil is a necessary prerequisite for the P in the PR to become plant available. The dissolution of two PR materials, Gafsa (GPR) and Christmas Island A (CIPR), in six acid, Malaysian soils (pH in water 3.0–5.4) was examined in closed‐incubation and open‐leaching systems.…
The first part of this paper covers the questions: How can we obtain WBFs (waterproof breathable fabrics)? and What is available? A description of the technique to obtain such fabrics with a statement of general advantages and disadvantages is covered. There are three techniques: 1. High-density fabrics 2. Lamination:…
The piezo-, pyro- and dielectric properties of lanthanum modified lead zirconate titanate (PLZT) ceramics has been investigated as a function of Zr/Ti ratio for 4% La. The pyroelectric coefficients show a minima at the morphotropic phase boundary. The pyroelectric and dielectric properties show different transition te…
Composite repair patches are often cured under vacuum pressure only, and are therefore more porous than their autoclaved counterparts. Thus it is common practice to add extra plies to a composite patch, over and above the number in the original struc ture. However, there is little published work on how the number of e…
Abstract A short report of a new computer simulation of plastic deformation is given in a typical flexible chain glassy polymer–polypropylene. The model which makes no arbitrary assumptions about structure and modes of molecular segment relaxations is based on systematic static energy minimizations in a small periodic…
Powders and thin films of the following simple and complex oxides have been obtained from metal alkoxides: MIITiO3 (M= Mg, Ca-Ba), MM1/3B2/3O3 (M= Sr, Ba, M' = Mg-Zn; B= Nb, Ta); MNbO3(M= Li, Na); ZrTiO4; PbTiO3; PZT, PLZT-materials; M2BO4 (M= Li, Na; B= Mo, W), Bi2BO6(B= Mo, W); LixWO3, WO3, MoO3, Bi2O3-WO3(solid sol…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGlass formation and structure in non-oxide chalcogenide systems. The short range order of silver sulfide (Ag2S)-phosphorus sulfide (P2S5) glasses studied by phosphorus-31 MAS-NMR and dipolar NMR techniquesZhengming Zhang, John H. Kennedy, and Hellmut EckertCite this: J. Am.…
Fixation of NIL4 + and K+ by soil clays affects N and K availability to plants, and fixation may be a result of N source or method of application. An incubation study with urea, NH4Cl and KCl was conducted to evaluate NH4 + and K+ fixation in three southern Quebec soils. Soils contained significant amounts of native‐f…
We have investigated molecular motion and ordering in the smectic phases of a nonoriented antiferroelectric liquid crystal by means of C-13 NMR and powder X-ray diffraction. The marked line broadenings for core carbons observed by C-13 NMR indicate the existence of the characteristic molecular motion for the molecular…
The periodic nonlinear behavior of a multilimb three-phase transformer is modeled in the harmonic domain, a frame of reference which allows cross-couplings between phases and between harmonics to be explicitly represented. The magnetic equivalent circuit is derived from the individual magnetizing characteristics of th…
A disordered nematic surface layer, with negative orientational order or biaxial order, is shown to result from interaction with substrates which favor random planar alignment. We propose a simple interaction Hamiltonian which yields predictions in excellent agreement with measured pretransitional effects for 4-n-pent…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of chemical composition distribution of poly(methyl methacrylate)-graft-polystyrene by adsorption high-performance liquid chromatographyShinya Teramachi, Akira Hasegawa, Tatsuya Matsumoto, Kiyoshi Kitahara, Yasuhisa Tsukahara, and Yuya YamashitaCite this: Macro…
A systematic geometrical analysis developed for symmetrical grain boundaries is extended to tilt asymmetrical boundaries in both f.c.c. and b.c.c. lattices. The presented scheme is compatible with the structural unit model in which so-called delimiting or favoured short-period grain boundaries play a special role. It…
Abstract The mechanical and electrical properties of solution‐processed [or gel‐spun] blends of poly(3‐octylthiophene) and ultrahigh molecular weight polyethylene are discussed. Tensile drawing at elevated temperatures of the phase‐separated blends resulted in significant improvements of the mechanical properties, in…
PURPOSE: To study the effects of iodinated radiographic contrast agents on proton relaxation in MR imaging. PATIENTS AND METHODS: Two patients were evaluated after the intrathecal administration of an iodinated nonionic contrast agent (Isovue) and five subjects with cranial tumors following the intravenous administrat…
Microporous prostheses of 1.5 mm internal diameter were fabricated with a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE)n co-polymer by the spray phase inversion technique. Some of the grafts were made piezoelectric by poling under a high electrical field. Overall, 24 poled grafts (P) and 24 unpoled grafts (UP)…
The Autler–Townes effect in nuclear magnetic resonance (NMR) and electron paramagnetic resonance has been observed using recently developed Raman heterodyne techniques. The measurements were carried out on the nitrogen-vacancy color center in diamond, where the 3A↔3E optical transition was driven by a single mode dye…
A mathematical model for the electrical hysteresis of ferroelectric thin-film capacitors based on the Landau free energy theory is presented. The hysteresis of a single ferroelectric crystallite is derived from free energy considerations. The hysteresis of a polycrystalline material is obtained by accounting for the s…