Materials Literature
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After a brief historical introduction, recent achievements in the theory of plasticity are surveyed with emphasis on applications in mechanical engineering. Kinematic models are presented that indicate the complexities of mechanical behaviour in the plastic range. The fundamental theorems of limit analysis are discuss…
Abstract The crystal structure of nylon 6 (NH (CH 2 ) 5 CO) p has been determined by interpretation of the x‐ray diffraction patterns given by drawn, rolled fibers. The determination was part of a program to investigate the relation between structure and physical properties, in particular melting point. Nylon 6 melt…
The optical rotation phenomena exhibited by a citrate-extracted fraction of ichthyocol (from carp swim bladder), as well as by the parent gelatin derived therefrom, have been studied. Dispersion data for all cases follow a single-term Drude equation, but the variations with state are adequately expressed by simple ref…
The Hall coefficient, magnetoresistance, and magnetic susceptibility of a graphite single crystal have been measured at liquid helium temperatures and in magnetic fields up to 25 kilogauss. All three phenomena are periodic functions of reciprocal field and exhibit the same period for like orientations of the crystal a…
The coefficients in the equation of state of BaTi${\mathrm{O}}_{3}$ proposed by Devonshire can be considered as describing the polarization and temperature dependence of the dielectric constant. This dependence has been studied by a dynamic method. The polarization is developed by a large-amplitude at field and the di…
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…