Materials Literature
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In thin polycrystalline gold films of four different thicknesses the average grain diameter is varied by different heat treatments. The resistivity as a function of temperature and grain diameter can be analysed satisfactorily in terms of grain-boundary scattering alone. The result is identical with experiments in whi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReductive chemistry of nickel hydroporphyrins: the nickel(I) octaethylisobacteriochlorin anionAlan M. Stolzenberg and Matthew T. StershicCite this: Inorg. Chem. 1987, 26, 19, 3082–3083Publication Date (Print):September 1, 1987Publication History Published online1 May 2002Pub…
Abstract In the Rietveld method for the analysis of powder diffraction data the entire pattern is calculated using a model for the positions of the peaks (the unit cell parameters), their intensities (dependent on the atomic positional and thermal parameters, preferred orientation, etc.) and their widths and shapes, t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPseudoliquid behavior of heteropoly compound catalysts. Unusual pressure dependences of the rate and selectivity for ethanol dehydrationMakoto Misono, Toshio Okuhara, Tatsumi Ichiki, Takeo Arai, and Yuji KandaCite this: J. Am. Chem. Soc. 1987, 109, 18, 5535–5536Publication D…
The absorption spectra of silver sols in various stages of particle aggregation, as well as the surface-enhanced Raman scattering (SERS) excitation of citrate adsorbed on the colloid particles have been deconvoluted into a set of Gaussian bands. The absorption wavelength variation upon aggregation of the silver sols c…
X-ray measurements on liquid-crystalline main chain polymers and on combined polymers (polymers with the mesogenic groups in the main chain as well as in the side groups) before and after cross-linking allow the identification of the different liquid-crystalline phases. Smectic A, smectic B and probably smectic C phas…
In the Czochralski process a single crystal is grown from liquid in a crucible. An axial magnetic field suppresses turbulence in the melt and thus reduces the density of microdefects in the crystal. This paper treats the melt motion due to buoyancy and thermocapillarity. The magnitude of this motion decreases roughly…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of boron nitride ceramics from poly(borazinylamine) precursorsChaitanya K. Narula, Riley Schaeffer, Robert T. Paine, Abhaya Datye, and William F. HammetterCite this: J. Am. Chem. Soc. 1987, 109, 18, 5556–5557Publication Date (Print):September 1, 1987Publication His…
Polyazines, H2N—[N=C(CH3)—C(CH3)—N]x—NH2, of various chain lengths have been prepared and studied by IR spectroscopy. An X-ray crystal structure was done on the monomer of this series, 2,3-butanedione dihydrazone (x = 1). It crystallized in space group P42/n with cell constants a = 12.172 (3) A and c = 4.115 (1) A and…
Classical dielectric theory is developed to provide an analytical expression for the energy losses experienced by a fast charged particle passing close to a dielectric sphere. The results are compared with energy loss spectra obtained from Ag catalyst particles in a scanning transmission electron microscope. In practi…
Electric-field-induced second-harmonic generation experiments on polydiacetylene solutions in dimethylformamide and in chloroform at 1.064 \ensuremath{\mu}m fundamental wavelength are presented. The technique allows for the measurements of both modulus and phase of the cubic susceptibility ${\ensuremath{\chi}}^{(3)}$(…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMixed-ligand chelate extraction of lanthanides with 1-phenyl-3-methyl-4-(trifluoroacetyl)-5-pyrazolone and some phosphine oxide compoundsShigeo Umetani and H. FreiserCite this: Inorg. Chem. 1987, 26, 19, 3179–3181Publication Date (Print):September 1, 1987Publication History…
The surface enrichment of Ca on various crystalloraphic planes of CaO‐doped sapphire has been measured as a function of annealing temperature using Auger electron spectroscopy (AES). Strong Ca enrichment was found on the (10 1 0) prism plane at ≥1300°C, whereas no evidence or Ca segregation could be observed on the (0…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new route to trimethylsilylated spherosilicates. Synthesis and structure of [Si12O18](OSiMe3)12, D3h-[Si14O21](OSiMe3)14, and C2v-[Si14O21](OSiMe3)14P. A. Agaskar, V. W. Day, and W. G. KlempererCite this: J. Am. Chem. Soc. 1987, 109, 18, 5554–5556Publication Date (Print):S…
The impedance of poly(vinylferrocene) (PVF) films coated on Pt electrodes and immersed in acetonitrile solutions containing 0.1 M tetra(n‐butylammonium) perchlorate has been examined. Three distinct regions are observed in the complex impedance plots for these films: kinetic control at high frequencies, diffusional co…
Abstract Voltammetric measurements on selected polypyrrole (PPy) films and defined soluble oligomers belonging to the oligo‐p‐phenylene and the oligo‐p‐phenylenevinylene series provide new insights into the charging/discharging properties of conducting polymers. It turns out that the current response in the whole acce…
A comprehensive study of the thickness dependence of the phase diagram of freely suspended films of the liquid crystal 4-n-heptyloxybenzylidene-4-n-heptylaniline (7O.7) between 50 and 69 \ifmmode^\circ\else\textdegree\fi{}C is reported. In thick films (thicker than about 300 layers and characteristic of bulk samples)…
Since the contribution of transformation toughening increases with the loca crack resistance (which is proportional to the toughness of the matrix), ZrO 2 particles were added to a toughened, whisker‐reinforced ceramic matrix. Analysis revealed that the combination of these multiple toughening agents should result in…
The aim of cytochemical techniques is to localize specific biochemical components in particular tissue and cell compartments. However, since preparation of tissues for structural observation results in major alterations of the properties of their components, a major problem is to retain an adequate degree of their bio…
Phase transitions of a system showing incommensurate phase and also critical point between commensurate and para-electric phases are studtied in an electric field. An effect of higher harmonics of the modulated phase on an appearance of a tricritical point is discussed. Some comments on the phase transition of NaNO 2…