Materials Literature
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Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans the biological, physical, and social sciences.
Single crystals of ${\mathrm{Cd}}_{2}$${\mathrm{Nb}}_{2}$${\mathrm{O}}_{7}$ have been grown, and dielectric, x-ray, and optical studies have been carried out on these above and below the ferroelectric Curie point. The x-ray analysis confirms the pyrochlore structure, and gives the oxygen parameter $x=0.305$ at room te…
The nucleation and growth of 90\ifmmode^\circ\else\textdegree\fi{} and 180\ifmmode^\circ\else\textdegree\fi{} domains in barium titanate single crystals have been measured with optical techniques. Both types of domains nucleate as long thin wedges with an initial velocity of the order of ${10}^{4}$ cm/sec for a drivin…
Abstract Dissipation of latent heat being the main rate-controlling factor in crystal growth from the melt, a novel technique has been developed for the rapid growth of monocrystals of germanium and other materials with the diamond or zincblende structure. By dipping a properly orientated seed crystal into an under-co…
Die Äthylate des Calciums, Strontiums und Bariums reagieren in siedendem Tetrahydrofuran leicht mit Diboran unter Bildung von Boranaten: 3 Me(OR) 2 + 4 (BH 3 ) 2 → 3 Me[BH 4 ] 2 + 2 B(OR) 3 , die dabei in Form kristalliner Di-tetrahydrofuranate Me[BH 4 ] 2 ·OC 4 H 8 isolierbar sind. In Äther verläuft die Umsetzung nur…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Degradation of Collagen. II. The Solubilization Process in the Acid pH RangeArthur Veis and Jerome CohenCite this: J. Am. Chem. Soc. 1955, 77, 9, 2364–2368Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https:…
Die Hydride des Calciums, Strontiums und Bariums wandeln sich in siedendem Tetrahydrofuran beim Einleiten von Diboran leicht in Boranate um: MeH 2 + (BH 3 ) 2 → Me(BH 4 ) 2 . Bei Verwendung von Äther statt Tetrahydrofuran tritt diese Reaktion nicht ein.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA Mechanical Resolution of dl-Methadone BaseHarold E. ZauggCite this: J. Am. Chem. Soc. 1955, 77, 10, 2910Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https://pubs.acs.org/doi/10.1021/ja01615a084https://doi.org…
The chemical resistance of mixed‐alkali glasses to water was measured by determining the sodium, potassium, calcium, and silicon ions extracted instead of evaluating it from the alkalinity of the mixed‐alkali extracts. In glasses of the composition K 2 O and Na 2 O 18, CaO 10, and SiO 2 72% the minimum extraction of a…
Die Tetramethoxoborate des Magnesiums, Calciums, Strontiums und Bariums reagieren in Tetrahydrofuran mit Diboran glatt und quantitativ unter Bildung von Boranaten Me[BH 4 ] 2 : 3 Me[B(OR)4] 3 + 4 (BH 3 ) 2 →· 3 Me[BH 4 ] 2 + 8 B(OR) 3 . Die Boranate lassen sich dabei in Form kristallisierter Di-tetra-hydrofuranate Me[…
Equations relating dipole velocity and dipole length matrix elements have been tested for π electron systems treated by a molecular orbital method. Considerable improvement in the validity of the equations is noted when configuration interaction is included in the calculations.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Heats of Combustion and Formation of Boron CarbideD. Smith, A. S. Dworkin, and E. R. Van ArtsdalenCite this: J. Am. Chem. Soc. 1955, 77, 9, 2654–2656Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https://pubs…
Ferroelectric films of BaTiO3 approximately 1 to 2 microns thick have been formed on platinum substrates by evaporation in a vacuum and a subsequent heat treatment in air. The structure of the crystallites which make up the films is mainly perovskite with the hexagonal phase as a minor constituent. Dielectric measurem…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Lanthanum Hydroxide Gel Promoted Hydrolysis of Phosphate EstersW. W. Butcher and F. H. WestheimerCite this: J. Am. Chem. Soc. 1955, 77, 9, 2420–2424Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https://doi.o…
In many applications it is necessary to determine the diffraction pattern due to monochromatic radiation. When the x-ray beam contains two frequencies α1 and α2, the experimental pattern P(2θ) equals the sum of the contributions f(2θ) and kf(2θ−δ) of the α1 and α2 components. In this paper a graphical method of determ…
A theory of the structure of glasses is presented. It is assumed that the volume and various other properties can be computed additively from contributions characteristic of the types of “structon” present, a structon being defined as an atom surrounded by close neighbors in a specific way. If the possible types of st…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAdsorption of Iodine and Bromine by Carbon BlackJ. W. Watson and D. ParkinsonCite this: Ind. Eng. Chem. 1955, 47, 5, 1053–1062Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https://doi.org/10.1021/ie50545a049Requ…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical Reactions in the Making of Cellulose AcetateCarl J. Malm and Leo J. TangheCite this: Ind. Eng. Chem. 1955, 47, 5, 995–999Publication Date (Print):May 1, 1955Publication History Published online1 May 2002Published inissue 1 May 1955https://pubs.acs.org/doi/10.1021/ie…
Recent cotton processing studies conducted by Textile Research Institute have demonstrated that the presence of a large number of short fibers in cotton causes appre ciable increases in processing wastes, excessively uneven rovings and yarns, less efficient spinning, and weaker yarns than would otherwise be expected.…
A theoretical and experimental analysis is given of small particle x-ray scattering by fibers. The scattering by different fibers of high orientation is compared with the theoretical scattering curves derived for independent scattering by an assemblage of parallel cylinders. Under certain conditions of swelling, excel…