Materials Literature
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It is shown that there is a size below which a coherent spherical precipitate cannot maintain a dislocation loop at its interface. There is also a size above which the incoherent (i.e. dislocated) state is stable with respect to the coherent state. Experiments in the electron microscope show that there is indeed a siz…
Crevice corrosion of titanium in high temperature sodium chloride solutions was investigated, Corrosion occurred only in very restricted crevices and attack was greater the higher the salt concentration. It was shown that crevice corrosion occurs because of the development of a low ( ~1) pH in the solution within the…
The flow stress distribution below the surface of previously deformed large copper single crystals is obtained when these are sliced into smaller component crystals. It is found that a considerable flow stress gradient extends for a distance of about 2 mm below the surface, measured along the slip direction. Electron…
Electrolytic charging of hydrogen onto Type 304L stainless steel at room temperature and 100 C (212 F) induced partial transformation of the austenite to the same martensitic phases [α′(bcc) and ε (hcp)] as are formed by cold-working hydrogen-free austenite at low temperatures (-196 C) (-321 F). No evidence of a hexag…
The energy spectra of Auger electrons from clean Au, Ag, Cu, Pd, and Ni surfaces have been determined. Uniform deposition of a second metal onto clean metal surfaces has made it possible to assess the depth of the surface region which contributes to the Auger peaks in the secondary electron energy distribution charact…
Abstract In order to get information about the mechanism of the thermal decomposition of hexamethylene tetramine (hexa), hexa was decomposed thermally in a vacuum vessel, and the composition of the gas thus produced was determined with a mass spectrometer. The main products found were ammonia and a carbon-rich solid r…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrolytic hydrogen evolution reaction on aluminum in acidic solutionsAshok K. VijhCite this: J. Phys. Chem. 1968, 72, 4, 1148–1156Publication Date (Print):April 1, 1968Publication History Published online1 May 2002Published inissue 1 April 1968https://pubs.acs.org/doi/10.…
Abstract A criterion of tensile failure in terms of energy density and energy loss at break has been developed for several gum rubbers over a wide range of test temperature. A similar description of failure in filled rubbers is related to the gum criterion by a simple elastic interaction term. The upper and lower limi…
Young's modulus and the shear modulus (at room temperature) are reported for the first time for bulk isotropic graphites of various porosities. Extrapolations to zero porosity indicate Young's modulus and the shear modulus of theoretically dense isotropic graphite to be 255 kilobars and 97 kilobars respectively. Poiss…
The crystal structure of CS2 was determined at two temperatures from intensity data measured with a proportional counter and a modified Weissenberg apparatus. The orthorhombic cell [(a) 6.3437(8), (b) 5.5244(4), (c) 8.9971(7), 143°K, Cmca, Z = 4] exhibited marked anisotropic thermal expansion, the coefficients of ther…
Small prolate spheroids of silver (between 140 and 400 Å av diam) were produced by photographic development of fine-grain silver bromide embedded in gelatin. The shape and size distributions of the silver particles were determined from electron micrographs of thin sections. The average axial ratios of these spheroids…
Direct experimental determinations are reported of the kinetics of O-atom attack of pyrolytic graphite at surface temperatures up to 2100°K. Comparisons with data obtained under identical conditions for lower-density isotropic graphites reveal that in atomic oxygen pyrolytic graphite is not much more oxidation-resista…
A review is given of the theory of magnetic groups and of their unitary corepresentations. Particular application is made to magnetic space groups, this part of the work being set in the framework of little-group theory. The symmetry problems in physics which lead to magnetic groups are analyzed and various applicatio…
Abstract Durch partielle Oxydation von K 2 [Pt(CN) 4 ] wie durch partielle Reduktion von K 2 [Pt(CN) 4 X 2 ] (X ‐ Cl, Br) erhält man kupferfarbige Produkte der Zusammensetzung K 2 [Pt(CN) 4 ]X 0,3 · 2,5 H 2 O. Sie bilden tetragonale Nadeln, die zur Raumgruppe P4/mmm gehören. Die Gitterkonstanten der Chlorverbindung si…
Vibrational frequency spectra are presented for vitreous silica, germania and beryllium fluoride; these have been computed from atomic arrangements in physical models described in an earlier paper. The positions of bands in the computed spectra agree well with observed bands in the experimental infra-red and Raman spe…
A transmission electron microscope study of four semi-coherent precipitates (θ’ in Al–Cu, S in Al–Cu–Mg, β’ in Al–Mg–Si and γ’ in Ni–Cr–Ti–Al) has revealed a misfit dislocation structure at their semi-coherent interfaces. The general visibility criteria for interface dislocations are considered and a Burgers vector an…
The desirability and requirements for a specimen capable of testing the resolving power and other image characteristics of an electron microscope are discussed in detail. In this discussion, the underlying diffraction phenomena are particularly utilized. A partially graphitized carbon black is shown to satisfy the req…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of Hydrogen Reduction of Manganese DioxideH. E. Barner and C. L. MantellCite this: Ind. Eng. Chem. Proc. Des. Dev. 1968, 7, 2, 285–294Publication Date (Print):April 1, 1968Publication History Published online1 May 2002Published inissue 1 April 1968https://pubs.acs.o…
With use of an electronic picture-scanning device and a digital computer, electron micrographs taken of a specimen along several different directions can be superimposed to form a montage that is more informative than the component images. Preliminary results indicate that one may thus study unstained, unshadowed biol…
Radiative corrections to bremsstrahlung and pair-production cross sections have been detected experimentally by measuring the thin-target bremsstrahlung spectrum of 5-GeV electrons with a pair spectrometer. Deviations of up to 5% from lowest-order calculations have been observed and found to agree with predictions for…