Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
Abstract The intrinsic viscosity and molecular weight of several samples of polyhydroxyethylaspartamide with differing degrees of polymerization were determined and related, according to the Mark‐Howink equation. The a exponent is consistent with a random‐coil structure. The average unperturbed dimensions of the polym…
Silica‐free phases which have a structure similar to that of mullite can be crystallized from gels in the Na 2 O‐Al 2 O 3 and (Na,K) 2 O‐BaO‐Al 2 O 3 systems. A gelation step appears to be necessary, since a solid‐state reaction between Na 2 CO 3 and Al(OH) 3 does not give the mullite‐type phase. Crystallization of th…
Abstract The glass‐transition region of crosslinked polymers prepared from poly(1,2‐propylene phthalate fumarate) and styrene was studied using a torsion pendulum. The glass‐transition temperature and the modulus in the rubbery region of these polymers were analyzed in terms of the crosslink density. The styrene conce…
The third-order elastic constants of hexagonal and cubic structures are related using an extension of a transformation derived by Martin. The transformation is used to calculate the zinc-blende second- and third-order elastic constants of CdS from the experimental wurtzite elastic constants. Also, the transformation i…
Technical Briefs A New Criterion for Brittle Creep Rupture H. Broberg H. Broberg Division of Solid Mechanics, Chalmers University of Technology, Gothenburg, Sweden Search for other works by this author on: This Site PubMed Google Scholar Author and Article Information H. Broberg Division of Solid Mechanics, Chalmers U…
Hexagonal ε-FexN phases with 2.02<x<2.85 were prepared from finely divided carbonyl Fe and NH3/H2 mixtures at 350 °C. Both the Curie temperature and magnetic moment decrease with increasing nitrogen content and approach zero at ∼Fe2N, the limiting composition of the hexagonal phase. The coercive force wa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDynamic Mechanical Properties of Cross-Linked Rubbers. VII. Butyl Rubber NetworksJames F. Sanders and John D. FerryCite this: Macromolecules 1974, 7, 5, 681–684Publication Date (Print):September 1, 1974Publication History Published online1 May 2002Published inissue 1 Septemb…
Abstract The kinetic parameters associated with the thermal decomposition of native collagen have been obtained by thermogravimetric techniques. In order to achieve this a thermogravimetric analysis was carried out in the temperature range of 25°C to about 1000°C. In this temperature range, it had been found that the…
Hexagonal nickel sulfide NiS shows a metal-nonmetal transition with the appearance of antiferromagnetism as temperature is lowered below 265 K ( T t ). Measurements of conductivity, Hall coefficient, thermoelectric power and magnetoresistance were made on polycrystalline samples of hexagonal Ni 1- x S (0.004≦ x ≦0.050…
Abstract Thermodynamic properties of molten polyethylene are calculated for the temperature range 100° to 300°C and for pressures up to 3000 atmospheres. The calculations are based on limited experimental data augmented by a corresponding‐states correlation and an empirical equation of state. Specific volume, internal…
The viscoelastic properties of nine silicone-, polysulfide-, and polyether-based impression materials were determined using creep tests. During deformation the materials demonstrated linear viscoelastic behavior. The creep compliance curves, recovery, and percent set were calculated. Permanent deformation in these mat…
The electronic states of Mn ions in barium titanate have been studied on Mn-doped and Mn, Gd-codoped Ba0.97Sr0.03TiO3 single crystals, using ESR and optical absorption techniques. It was found from ESR measurements that Mn ions substitute at the B sites and exist as Mn2+ in reduced crystals and Gd-doped crystals, and…
The energy barrier to internal N—N bond rotation in five cyclic and two bicyclic N-nitrosamines [Formula: see text]has been determined using high temperature 100 MHz n.m.r. spectroscopy. A substantial contribution from the ionic resonance structure of [Formula: see text] produces considerable double bond character in…
Smectics A are fluid, layered, materials which obey Darcy's law for flow normal to the layers, and an equation of the Navier-Stokes type in the other two directions. The slow motions of various solid bodies inside a smectic are discussed, assuming that the layers are not distorted around the solid at rest. The flow pa…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Thermal Breakdown of Poly(diphenoxyphosphazene)H. R. Allcock, G. Y. Moore, and W. J. CookCite this: Macromolecules 1974, 7, 5, 571–575Publication Date (Print):September 1, 1974Publication History Published online1 May 2002Published inissue 1 September 1974https://pubs.ac…
A new approach, based on the magnetic vector potential, is developed for the solution of flux penetration and eddy current problems in nonlinear ferromagnetic materials. The model obtained for this diffusion problem is useful in the sinusoidal time varying cases, and can be extended to the general time varying cases.…
Summary The compositions of feldspar pairs crystallized from stoichiometric alkali feldspar gels with water at P H 2 O ≈ 1 kbar in runs of up to 3000 hours' duration vary with Na:K in the starting material. This is because, for most bulk compositions, rapid nucleation in the gel leads to growth of one feldspar phase o…
Dislocation structures in sapphire deformed by basal slip at 1200° to 1500°C were studied by transmission electron microscopy. Long dislocation dipoles of edge character are formed by interactions of dislocations on parallel basal planes (“edge‐trapping”); screw dislocations annihilate by cross‐slip. The accumulation…
The free energy for a system of hard spherocylinders with midpoints constrained to random motion in a plane, serving as a zeroth-order approximation to one layer of a smectic liquid crystal or a two-dimensional nematic liquid crystal, has been calculated for spherocylinders with a length-to-width ratio of 5. For $\ens…
Abstract The mechanism by which low profile character is achieved in unsaturated polyester systems has been investigated. Using techniques of microscopy, data are developed that support a model in which micro stress cracking is induced to relieve stress promoted by polymerization shrinkage. Thus the strain is accommod…