Materials Literature
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It has been shown with single crystals, bicrystals, and polycrystalline material that the strength of magnesium oxide depends on the availability of mobile dislocation sources. Mobile dislocations, introduced by mechanical contact at the surface, are responsible for the ductility normally observed in single crystals.…
The susceptible paths for stress corrosion cracking in Type 304 stainless steels were identified by electron microscopic examination of thin sections before and after exposure to boiling 42 percent MgCl2 These paths were found to be generated by the corrosion reaction, particuarly the cathodic part of this reaction. T…
Archard's diffusion model of electron back-scattering is discussed on the basis of a result obtained by Tomlin and Metchnik in 1963 in their treatment of x-ray emission intensities. The resulting simple formula for the back-scattering coefficient is in reasonably good agreement with measured values.
The effect of load on initial neck growth between alumina single‐crystal spheres has been measured at 1530°C. The neck areas are larger than those observed in pressureless sintering and constant for all times between 10 and 480 minutes. The neck areas are proportional to the loads; i.e. they equilibrate at equal stres…
The crystal structure of kyanite, Al 2 SiO 5 , has been refined by three-dimensional least-squares techniques. Refinement was based on observed data measured using a single-crystal counter diffractometer, and reduced the disagreement factor, R , for 981 hkl reflections to 8.6%. The triclinic kyanite structure proposed…
It is shown that the spin Hamiltonian for ${\mathrm{Cr}}^{3+}$ ions in the ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ lattice has to be augmented by a term $\ensuremath{\Sigma}{i}^{}\ensuremath{\Sigma}{j\ensuremath{\le}k}^{}\frac{1}{2}{R}_{\mathrm{ijk}}{E}_{i}({S}_{j}{S}_{k}+{S}_{k}{S}_{j})$ in the presence of an externall…
By means of transmission electron microscopy, ferromagnetic domain structures have been studied in thin cementite (Fe3C) particles embedded in a ferrite matrix. In general, the domain structure was found to consist of parallel strips alternately magnetized along the positive and negative direction of the easy axis of…
The possibility that terms other than Fermi contact interaction make significant contributions to nuclear spin-spin coupling with heavy nuclei has stimulated considerable interest in the n.m.r. spectra of compounds containing heteroatoms. In particular, relative signs and magnitudes of J_(XCH) and J_(XCCH) have be en…
Growth of heavily doped germanium and silicon crystals is investigated from the standpoint of constitutional supercooling. When the impurity concentration exceeds a certain value, corrugations appear on the crystal surface. The impurity concentration necessary for the appearance of the corrugation, the doping limit, i…
The Cavitation Damage Number proposed by the author has been modified to incorporate the concept of strain-energy instead of the dynamic yield stress of the material. The correlation between the Cavitation Damage Number and the Number of Cavities has been extended to different materials and different sizes. A third no…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTINTRAMOLECULAR HYDROGEN BONDING IN o-NITROBENZALDEHYDE AND RELATED COMPOUNDSS. PinchasCite this: J. Phys. Chem. 1963, 67, 9, 1862–1865Publication Date (Print):September 1, 1963Publication History Published online1 May 2002Published inissue 1 September 1963https://pubs.acs.or…
Natural graphite single crystals and polycrystals have been deformed at room temperature and optical and electron microscope studies of these have been coupled with x-ray investigations. The appearance and disappearance of x-ray diffraction peaks corresponding to the rhombohedral structure has been investigated. After…
The attenuation of shock waves in 2024 aluminum has been studied experimentally by impacting aluminum flyer plates upon aluminum targets and measuring the target-free surface velocity as a function of target thickness. The results disagree with the predictions of hydrodynamic theory, exhibiting premature attenuation.…
A new species of brackish-water diatom, Cyclotella cryptica, is described on the basis of structural details of the cleaned shells from cells of different sizes grown in culture. This species resembles C. meneghiniana in the light microscope but can be clearly distinguished by electron microscopy.
Summary By measuring the integrated line intensity on a Philips' X-ray diffractometer in place of the peak intensity and by paying due regard to the ease with which aragonite converts to calcite during cleaning and grinding operations, the proportion of calcite and aragonite in a pure calcium carbonate shell can be de…
Abstract A molecular theory is presented in this paper which gives a method of analysis for the mechanical properties of filler-reinforced elastomers, based upon the concept of the internal deformation and the statistical theory of rubberlike elasticity. By using a suitable model and a few new concepts a proper analys…
The transmittance and reflectivity of metal meshes made of brass wire were measured in the far infrared region. The reflectivity of these meshes is very low in the wavelength region up to the wavelength of about 1.3 times the mesh constant, but then increases steeply so that the mesh becomes a nearly perfect reflector…
If an energetic atom, a primary, slows down in a lattice, it has the possibility of traveling long distances without essential interaction along almost force-free channels bordered by close-packed atomic chains. This effect has not been considered until recently, because, for the sake of simplicity, the lattice has be…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Protonation of PyrrolesY. Chiang and E. B. WhippleCite this: J. Am. Chem. Soc. 1963, 85, 18, 2763–2767Publication Date (Print):September 1, 1963Publication History Published online1 May 2002Published inissue 1 September 1963https://pubs.acs.org/doi/10.1021/ja00901a020htt…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRhenium Catalysts. VII. Rhenium(VI) Oxide1H. Smith Broadbent and William J. BartleyCite this: J. Org. Chem. 1963, 28, 9, 2345–2347Publication Date (Print):September 1, 1963Publication History Published online1 May 2002Published inissue 1 September 1963https://pubs.acs.org/do…