Materials Literature
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A trial-and-error method is described for facilitating the indexing of X-ray powder patterns with the help of a computer. It is based on the variation of parameters by dichotomy, i.e. successive division of available phase space. The observational errors are rigorously treated. The program, written in Fortran IV, pres…
From observations of the characteristics of nitrate and hydroxide solutions, known to promote stress corrosion cracking (SCC) in carbon steels, and from the form of potentiodynamic polarization curves and the structural dependence of the corrosive attack, it was predicted that carbonate solutions would also produce in…
M\"ossbauer studies combined with magnetic-susceptibility data on well-characterized LaCo${\mathrm{O}}_{3}$ in the 4.2-1200-K region show that cobalt ions exist predominantly in the low-spin ${\mathrm{Co}}^{\mathrm{III}}$ state at low temperatures which transform partially to high-spin ${\mathrm{Co}}^{3+}$ ions up to…
Abstract Consideration of the relation between the cohesive energy and the surface free energy leads to the inference that dissolved hydrogen reduces the maximum cohesive resistive force of which the iron lattice is capable. This forms the basis of a mechanistic model for the velocity of hydrogen‐induced crack propaga…
The perovskite-like compounds RE(1-X)Pb(5)MnO(3) and RECoO(3), where RE (rare earth) is lanthanum, praseodymium, or neodymium, are active catalysts for the oxidation of carbon monoxide. Crushed single crystals of these compounds compare favorably with commercial platinum catalysts in initial activity and lifetime. The…
Abstract Under certain conditions it is possible to obtain the approximate projected density of a specimen from an electron micrograph, and by taking electron micrographs in different directions a number of different projections of a specimen can be determined. Several methods have been proposed for reconstructing the…
Abstract The compositions of copolymers formed by reacting styrene or α‐methylstyrene (M) with lithium in tetrahydrofuran in the presence of varying amounts of alkyl dibromides (RX 2 ) have been studied. Regular copolymers of structure are formed at 2:1 monomer to dibromide molar stoichiometry, but they become less re…
Electron diffraction patterns having 3500 reflections out to 2 angstromns were obtained from wet microcrystals of catalase. No diffraction was obtained if the water vapor pressure was set below 90 percent of the equilibrium value.
Brief information is presented on the composition and properties of high-strength steels. Questions of their weldability are discussed, modern concepts of the causes and mechanism of cold and hot cracking are set forth and ways of preventing them are suggested. Information about the properties of weld joints, welding…
We have found that the substitutional replacement of Ti for Ta in Ta${\mathrm{S}}_{2}$ stabilizes the octahedral $1T$ phase for $x$ between 0.1 and 0.9. A comparison of the resistivity, magnetic susceptibility, and thermoelectric power shows that at room temperature the properties vary systematically from diamagnetic,…
An interpretation is given of the anisotropic chemical shift of the 59Co NMR line in a single, four-layer orthorhombic crystal of K3Co(CN)6 in terms of the digonally distorted octahedra of CN ions surrounding a cobalt ion. The various possible sources of contributions to the electric field gradient tensor (EFGT) at a…
The increase of the dislocation density during plastic deformation in high-pure and nickel doped copper single crystals, which was determined quantitatively by etching of emerging screw dislocations, is primarily dependent on the effective shear stress. An influence of the basic structure on the work-hardening charact…
An acoustic modulator using a liquid crystal and a piezoelectric driver is described. The response time of the modulator is less than the time needed for the onset of mechanical stress. Actually it is governed only by the electromechanical properties of the piezoelectric driver used.
Isolates from four sites were identified as varieties of the diatom Gomphonema parvulum Kütz. The material was examined by light and electron microscopical techniques. A detailed account of the morphology of this species is given. No fundamental differences between the varieties were found apart from cell shape. It is…
The seasonal succession of algal species in the epipelon of two small pools over a period of three years is described in relation to changes in silica, nitrate-nitrogen and phosphate-phosphorus concentrations in the water above the sediments. Recurring patterns of seasonal growth of the various species are discussed.
The diagrammatical method for the calculation of the matrix elements of an arbitrary spin-independent operator in the basis of single antisymmetrized geminal products, developed in Part I, is applied to derive the overlap and energy mean value expressions for various types of geminal wavefunctions, namely for strongly…
The scanning electron microscope has provided much information about the structure of the valves of centric diatoms that supplements or, at times, corrects the accounts based on transmission electron microscopy. In particular, the morphology of the special features that have been called processes, spines, ocelli, tubu…
In order to determine quantitative information about chemical bonding in metallocenes, we investigated the electronic structure of the cobaltocene molecule by EPR and magnetic susceptibility measurements at 4.2°K and by optical spectroscopy at 77°K. Diamagnetic ruthenocene, weakly paramagnetic nickelocene, and paramag…
The relative emission per ion and the lifetime have been obtained as a function of Tb concentration for the $^{5}D_{4}$ to $^{7}F_{J}$ transitions in ${({\mathrm{Y}}_{1\ensuremath{-}x}{\mathrm{Tb}}_{x})}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ crystals. At 297 \ifmmode^\circ\else\textdegree\fi{}K both are concentration…
${\mathrm{Cd}}_{2}$Sn${\mathrm{O}}_{4}$ has been found to be an $n$-type defect semiconductor in which oxygen vacancies provide the donor states. Crystalline powders and amorphous films with a wide range of conductivities have been prepared. Large Burstein shifts have been observed in the visible reflection and transm…