Materials Literature
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Abstract It has been confirmed by means of electron diffraction that lath‐shaped crystals of polyethylene are {110} reflection twins in which the chain molecules adopt a regularly folded conformation. The orientation and habit of the spiral terraces (or steps) which grow on the {001} faces of these crystals through th…
The microscopic shape of a solid-liquid interface has been examined theoretically for those growth conditions which give rise to a cellular morphology. The method of obtaining a general solution is set forth, and approximate treatments are used to compare the theoretical approach with experimental data. The variation…
Force constant, dissociation energy, and equilibrium internuclear distance in a sequence of similar diatomic molecules have been found to be related by the expression kere/D0=const. The applicability of this relationship has been shown for eighteen sequences of similar molecules. With the help of this relationship, th…
The triplet excited states of porphin are classified as either singly or doubly excited electron configurations. The latter are discussed in detail in terms of a circular box model with electron interaction plus a perturbation due to the actual molecular shape. The energy and intensity of the triplet-triplet transitio…
Crystalline cesium triborate, Cs20.3 B203, has been prepared and the structure determined.The crystals belong to the space group P212121, with unit-cell dimensions a=6.18, b=8.48, c-9.17 A.A complete set of atomic parameters has been determined from electron-density projections along the two shortest axes.The structur…
The dissolution of single crystals of undoped germanium in Superoxol etchant is shown to be very closely completely orientation-dependent by the applicability of recent theorems on crystal dissolution shapes. The results of the theory are outlined, and the method of application is described in detail.
The temperature dependence of the Debye temperature of aluminum, lead, and beta brass was determined by measuring the integrated intensity of a high angle x-ray diffraction peak from each of the materials as a function of temperature. This measured temperature dependence agrees well with the corresponding function obt…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE GROWTH OF LARGE SINGLE CRYSTALS OF ZINC OXIDE1J. W. Nielsen and E. F. DearbornCite this: J. Phys. Chem. 1960, 64, 11, 1762–1763Publication Date (Print):November 1, 1960Publication History Published online1 May 2002Published inissue 1 November 1960https://pubs.acs.org/doi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermogravimetric MeasurementsA. E. NewkirkCite this: Anal. Chem. 1960, 32, 12, 1558–1563Publication Date (Print):November 1, 1960Publication History Published online1 May 2002Published inissue 1 November 1960https://doi.org/10.1021/ac60168a006RIGHTS & PERMISSIONSArticle Vie…
Measurements have been made of the characteristic electron energy loss spectra of beryllium, antimony, bismuth, germanium, tin, cadmium, copper, platinum, lead and calcium using the reflection technique and with 750 eV and 1500 eV primary electrons. The spectra of each element were found to consist almost entirely of…
. The effects of thickness errors are: (1) A shift of the wavelength at which maximum reflectance occurs; and (2) a change in phase shift upon reflection. The magnitude of these effects, and also their dependence on various parameters, are determined. Statistical tolerances for layer thicknesses are computed for given…
Abstract Capacity measurements obtained with an a.c. bridge have been used to determine the thickness of non‐porous oxide films on iron and aluminium surfaces, and for showing the effect of both the solvent action of aqueous solutions and electrochemical processes on the thickness of these films. These measurements co…
An interpretation is given to specific corrosion results obtained in field and laboratory investigations. The complex mutual interaction of corrosion stimulating and inhibiting factors (pH, buffer capacity, CaCO3 deposition, and alkalinity) is treated.
The precipitation kinetics of a gold l·5%, by weight, cobalt alloy have been followed by measuring the sàturation magnetization of the precipitated cobalt and the results are compared with current theories. Marked differences were found between the ageing curves of air and water-quenched specimens. The remanent magnet…
Macromolecular chains in freely growing crystals very likely fold back at regular intervals in order to minimize the free energy density of the crystal. The surface energy contribution favors infinite thickness. The smearing out effect of interchain potential field, however, arising from the incoherent part of fluctua…
The thermomagnetic properties of the compound Cr 2 As and Cu 2 Sb were investigated together with the phase diagram of Cr–As system. From the results of thermal and thermomagnetic measurements for Cr 2 As and Cu 2 Sb it was found that they show antiferromagnetic behavior with the Néel point at 393°K and at 373°K respe…
Crystallographical properties of the chemically prepared powder samples of Ag 2 O and Cu 2 O were investigated by an X-ray diffractometer, in relation to their bonding characters. The lattice constant is 4.720±0.004A for Ag 2 O and 4.268±0.001A for Cu 2 O. The thermal expansion coefficient of the lattice is 1.9×10 -6…
ABSTRACT Age measurements on glauconite by the K-Ar and Rb-Sr methods show a consistent variation with geological age with moderately small scatter. The results appear to fall 10-20 per cent short of ages measured on micas associated with dated igneous rocks. K-Ar and Rb-Sr age values are closely concordant in the maj…
The behavior of a permanent gas bubble in a liquid with an oscillating pressure field is analyzed with a linearized theory. If the assumption is made that conditions within the bubble are uniform, the thermodynamic relations found are as expected; i.e., at low frequencies the bubble behaves isothermally and at high fr…
Abstract A set of definitions is proposed to describe uniquely the six types of orientation possible in semicrystalline polymeric films. Oriented polymer films were studied by a new x‐ray diffraction technique which permits rotation of a sample about a number of independent axes yielding orientation distributions of t…