Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXT(Pyridinylmethylidene)dithioles: synthesis, structure, and reactivityKevin T. Potts, Susan A. Nye, and Kennith A. SmithCite this: J. Org. Chem. 1992, 57, 14, 3895–3901Publication Date (Print):July 1, 1992Publication History Published online1 May 2002Published inissue 1 July…
Direct phasing methods based on the probabilistic estimate of triplet and quartet structure invariants are used to determine the crystal structure of boric acid from room-temperature electron diffraction data published by Cowley [Acta Cryst. (1953), 6, 522–529] and also new low-temperature data collected at or below 1…
Abstract 1,3‐Diethynyl‐5,7‐dimethyladamantane, 1,3‐diethynyl‐5‐phenyladamantane, 1,3,5‐triethynyladamantane, and 3,3′‐diethynyl‐1,1′‐biadamantane, were synthesized and polymerized thermally at 210°C. The thermoset resins obtained were post‐cured at 300°C for 16 h to give materials that exhibited onsets of degradation…
In previous work, a two-dimensional waveguide model has been developed and examined extensively so that rigorous light scattering calculations for photolithography-related processes, such as stepper alignment, linewidth and overlay measurements, and resist bleaching, can be performed. The computation, however, is expe…
The binding energy for CO2 adsorbed on Cu(100) has been determined by use of temperature programmed desorption and was found to increase with increasing coverage from 25 to 30 kJ mol−1. The presence of surface oxygen did not significantly increase the CO2 binding energy. High-resolution electron energy-loss spectra re…
Crystal structures in small Al-rich Fe particles were studied by powder X-ray diffraction and transmission electron microscopy. The specimens of the small particles were made by evaporating an Al alloy material containing 5.0-33.3 at.% Fe in Xe gas at a pressure of 3.3 × 103 Pa. The small particles were 70-150 nm in d…
Experimental data on d.c. leakage currents in lead zirconate titanate thin films (210 nm) are presented. The data show a flat, ohmic response up to a thresh-hold of approximately 2.0 V, above which they satisfy a modified Childl's Law, with a perfectly quadratic dependence: I = aV2. This suggests that at 5 V operation…
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…