Materials Literature
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Measurements are reported of the inelastic scattering cross sections associated with the characteristic energy losses of 20-keV electrons transmitted through thin films of Al, Be, and polystyrene. These measurements have been made using two techniques which overcome several sources of systematic error in previous meas…
In this second part of a study of the spin-lattice relaxation rate ${{T}_{1}}^{\ensuremath{-}1}$ in the temperature range $1.2\ensuremath{\leqq}T\ensuremath{\leqq}5\ifmmode^\circ\else\textdegree\fi{}$K of some trivalent rare-earth ions in the salts ${\mathrm{La}}_{2}$${\mathrm{Mg}}_{3}$${(\mathrm{N}{\mathrm{O}}_{3})}_…
In the usual treatment of the temperature dependence of spin-lattice relaxation of impurity ions, the vibrational properties of the paramagnetic ion are assumed to be those of a normal host ion. For impurities that do not affect the vibrational properties of the lattice, this is expected to be a resonable approximatio…
A Peltier–Seebeck or Harman type apparatus has been constructed to measure the Seebeclc coefficient, α, thermal conductivity, κ, electrical resistivity, ρ, and the figure of merit, Z, of thermoelectric materials over the range of temperature 150–300 °K while maintaining the sample in an approximately isothermal enviro…
Abstract 1,8-Di-p-tolyl-3,6-diphenyl-1,4,7-octaaztriene (DTDPO) was prepared by the potassium permanganate oxidation of 1-p-tolyl-3-phenyl-1-tetraazene (TPT), and the kinetics and the products of the decomposition of DTDPO were investigated. The experimental results can best be explained by assuming a mechanism in whi…
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text W. E. Müller, "Note on Reflectance Measurements on Metals," Appl. Opt. 5, 876-877 (1966) Export Citation BibTex Endnote (RIS) HTML Plain Text Citation…
The physics of the polymerization of irradiated trioxane crystals have been studied experimentally and theoretically. A geometrical comparison of the monomer and polymer crystal lattices suggests that growth of the polymer twins must occur in a synchronized fashion. The crystal field in the polar trioxane lattice has…
Eight aluminium alloyswereexposedat marine sites at Kure Beach, North Carolina; Arenzano, Italy; and Bohus-Malmon, Sweden. Panels were removed at the end of 1-, 2- and 5-year exposure periods and evaluated for depth of pitting, corrosion rate and loss of mechanical properties. The high-purity aluminium and certain alu…
Abstract Various expressions are presented for the estimation of kinetic parameters during pyrolysis from DTA traces. These expressions are applied to polytetrafluoroethylene, polyethylene, polypropylene, polystyrene, isotactic poly(propylene oxide), and poly(methyl methacrylate). The results obtained are compared wit…
The conversion of trioxane crystals to crystalline high polymer is a cooperative process, analogous in certain aspects to diffusionless (‘martensitic’) transitions in metals and alloys. The reaction, which involves ionic states, is closely related to the electret character of crystalline trioxane. Evidence in support…
Tungsten single crystals were neutron irradiated to exposures of 0·46, 2·4, 4·0 and 7·3×1019 nvt (E> 1 Mev) and examined by transmission electron microscopy. Defect clusters, observed after 2·4×1019 nvt, increased in size and concentration with increasing neutron exposure. One specimen irradiated to 7·3×1019 nvt was s…
Reflectance of CoAl and NiAl alloys with CsCl structure was measured in the spectral region between 7000 and 3000 Å. Structures in the reflectance curves are discussed in terms of interband transitions. Rigid-band approximation seems to be able to explain various physical properties of these alloys.
The optical constants n and k have been calculated for fused silica, three silicate glasses, and a phosphate glass from reflectance measurements made in the strong absorption region, from about 7 micro to 13 micro. Plots of the 2nkv product, which corresponds to the conductivity, as a function of frequency are used to…
Synthetic textile fibres in the drawn or extended state show considerable optical and mechanical anisotropy. A series of polypropylene fibres was made by drawing an isotropic spun fibre over as wide a range of draw ratios as possible and the extensional modulus, torsional modulus and optical birefringence were measure…
The analysis of linear dislocation arrays, piled up in the soft phase of a two-phase material, is extended. The equilibrium positions of dislocations are determined by numerical analysis. A result of the computation is the confirmation of the linear approximation L/n = (A/σ) (α+βK), 0<K≤1. Here, L is the length…
Abstract The effects of 60 Co γ‐radiation on polytetrafluoroethylene (PTFE) and polychlorotri‐fluoroethylene (PCTFE) have been studied for radiation doses up to 940 Mrad. The dependence of per cent crystallinity upon irradiation level has been determined from x‐ray analysis. An initial increase in crystallinity in PTF…
SYNOPSIS IN INTERLINGUA MAGNITUDE GRANULAR IN FUNDITE ALLICATOS DE AURO.—Le resistentia a traction e le elongamento de auros dental es augmentate quando le magnitude granular es raffinate. Le technica pro le raffinamento del grano in metallos fundite require le regulation del rapiditate con que nucleos de solidificati…
It is shown by contrast experiments that more than 95% of the dislocation loops observed in quenched aluminium (99·995% Al) have a Burgers vector 1/3<111> rather than 1/2<110>. This finding is confirmed by annealing experiments. The observation of large, faulted loops of dislocation in zonerefined aluminium (99·9999%…
Abstract Open-cell foams show abnormally large mechanical damping due to the energy dissipated in forcing air in and out of the foam during a deformation cycle. This pneumatic damping has recently been treated theoretically and experimentally. The dependence upon the test-piece dimensions, the frequency of deformation…
It has been shown that the overall kinetics of hydrogenation of coal can be explained on the basis of a two-stage reaction mechanism. The first stage involves the very rapid reaction of hydrogen with groupings in the coal which are associated with oxygen, and can be considered to be instantaneous in practical systems.…