Materials Literature
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Comparison is made between the electrical and thermal conductivities of solids and the transport properties of gases, with special reference to boundary limiting effects. The transition from continuum to molecular behaviour of gases is explored using a modified mean free path. Relative intermolecular and boundary coll…
Theoretical expressions derived previously for molecular size distributions in multichain polymers are applied to binary silicate melts. The treatment is an extension of a previous approach which was limited to the consideration of linear chains. When all configurations of the chain molecules are taken into considerat…
It is suggested that there may be three types of nematic phases: the skewed cybotactic phase, in which the molecules are arranged in groups in such a way that the centers of the molecules in each group lie in a plane making an angle α (significantly different from 90°) with the mean direction of the molecules in that…
An analysis is given of the collapse of a spherical cavity in a large body of an incompressible viscoelastic liquid. Proceeding from a linear rheological model for the liquid, one obtains a nonlinear integro-differential equation for the motion of the cavity. Analytical solutions are derived for certain limiting value…
1. The absorption spectra of deutero- and proto-ferrihaem in aqueous solution at 25 degrees C show marked changes with concentration and pH in the Soret band region. Quantitative studies of these phenomena imply that they are associated with ferrihaem dimerization and with protolytic equilibria involving monomeric (M)…
Rate-dependent constitutive relations for single crystals are derived in terms of dislocation dynamics. Contributions from slip on the individual glide planes are assumed to superpose linearly to give the total plastic strain. As an application of the theory, equations describing elastic precursor decay are developed…
An attempt is made to differentiate between the three previously proposed models of the structure of tetragonal BaTiO3. In the new model, the serious parameter-interaction problem was avoided by the use of both neutron and X-ray diffraction data collected from c-domain single crystals. The result of the refinement gav…
The core lines and valence bands of LiF, BeO, BN and graphite have been studied by the ESCA technique. The energy differences between inner levels and valence bands are compared with X-ray transition energies. The changes in binding energy for the Bel s level when going from metal to oxide and fluoride are compared wi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeats of combustion and strain energies of bicyclo[n.m.O]alkanesSho-Ju Chang, Donal McNally, Shahrokh Shary-Tehrany, Sister Mary James Hickey, and Richard H. BoydCite this: J. Am. Chem. Soc. 1970, 92, 10, 3109–3118Publication Date (Print):May 1, 1970Publication History Publi…
Abstract Blends of poly(2,6‐dimethyl‐1,4‐phenylene ether) (PPO) and atactic polystyrene (PS) have been prepared by mechanically mixing powders of the two polymers and subjecting the mixtures to three different thermal treatments. Three different compositions were studied by the dynamic mechanical and DSC techniques. T…
Superconductivity persists in several, layered, transition metal dichalcogenide superconductors when the layers are spread apart to accommodate organic molecules between them. These materials are of interest not only because of their two-dimensional character but also because they may provide a means for examining hyp…
Second-order displacive transitions of a type often observed in crystals of perovskite structure are analyzed by means of a phenomenological model employing optical soft-mode and elastic-strain coordinates. Relations connecting spontaneous distortion, soft-mode vibrational frequencies, and elastic constants of a tetra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrochemical and electron paramagnetic resonance studies of metalloporphyrins and their electrochemical oxidation productsAlexander Wolberg and Joost ManassenCite this: J. Am. Chem. Soc. 1970, 92, 10, 2982–2991Publication Date (Print):May 1, 1970Publication History Publis…
Abstract The nonvolatile products in thermal‐oxidized polypropylene sheet have been quantitatively identified by infrared analysis and chemical reaction. The molecular weight changes with oxidation have been studied by gel‐permeation chromatography. It was determined that there is a functional group at each end of a c…
Hydrostatic-pressure measurements have shown that in PbZr${\mathrm{O}}_{3}$ the antiferroelectric (AFE)-paraelectric (PE) transition temperature ${T}_{a}$ increases ($\frac{d{T}_{a}}{\mathrm{dP}}=4.5\ifmmode\pm\else\textpm\fi{}0.3\ifmmode^\circ\else\textdegree\fi{}\mathrm{K}/\mathrm{kbar}$) whereas the extrapolated Cu…
The X-ray diffraction patterns of the nematic phase of bis-(4′-n-octyloxybenzal)-2-chloro-1, 4-phenylenediamine show major maxima at two diffraction angles. The ones at the larger angle are due to the interaction of neighboring, parallel molecules and the average distance between the long axes of the molecules can be…
1,l0-Phenanthroline-5,6-quinone is prepared from 1,l0-phenanthroline via 5-nitro-1,l0-phenanthroline and 5-amino-1,l0-phenanthroline. It is converted by standard methods into 4,5-diazafluoren-9-one, 4,5-diazafluoren-9-ol,4,5-diazafluorene, and the new heterocyclic system dipyrido[3,2-a:2',3'-clphenazine. These four co…
A relaxation-type calculation of the structure of the dislocation core has been made for the ½ 〈111〉 screw dislocation in b.c.c. crystals, using a variety of central-force potentials. Two stable configurations were found, corresponding to the centre of the dislocation being along either the left-hand or the right-hand…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhosphorus ligand exchange equilibriums on zerovalent nickel. Dominant role for steric effectsChadwick A. TolmanCite this: J. Am. Chem. Soc. 1970, 92, 10, 2956–2965Publication Date (Print):May 1, 1970Publication History Published online1 May 2002Published inissue 1 May 1970h…
Electron spectra from an extensive series of sulfur compounds have been studied. A correlation has been established between the observed position of inner electron lines of sulfur and structure. The influence of structure on the electron binding energies is discussed in terms of a calculated atomic charge, based on th…