Materials Literature
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The authors have continued their efforts to absolve the x-ray method of determining the electronic charge of the criticism that Bragg reflection determines the lattice dimensions in only a very shallow surface region whereas the density determinations have been made on a much larger volume of crystal. In earlier work…
Oscillographic studies have been made of the currents in negative point to plane coronas in air. The oscillograms obtained indicate that the negative corona current is composed of discrete pulses whose magnitude and frequency have a definite relationship to the corona current, point size and gas pressure. The frequenc…
described the isolation of water-soluble peptides from the brown alga Pelvetia canaliculata forma libera S. M. Baker and the red alga Corallina officinalis Lirn. It was then suggested that the presence of peptides in algae was due to a lack of metabolic balance determined either by desiccation or by low illumination.…
The paths of charged particles traversing a portion of an ideal spherical condenser are worked out. The section of the condenser considered is bounded by two rays, enclosing an angle $\ensuremath{\Phi}$, from the common center of curvature, $O$, of the equipotential surfaces. It is shown that a group of particles, hom…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydrogen Bonds Involving the C-H Link. V. The Solubility of Methylene Chloride in Donor SolventsM. J. Copley, G. F. Zellhoefer, and C. S. MarvelCite this: J. Am. Chem. Soc. 1938, 60, 11, 2714–2716Publication Date (Print):November 1, 1938Publication History Published online1…
X-ray diffraction patterns of water were obtained at five temperatures: 1.5°, 13°, 30°, 62°, and 83°C. The radiation was Cu Kα and Mo Kα, monochromated by reflection from a rocksalt crystal. Radial distribution curves for water at the five temperatures were obtained by a Fourier analysis of the x-ray intensity curves.…
Crystal structure analysis shows there can be no further doubt regarding the existence of the carbonate apatite or oxy-apatite molecules. Chemical analysis is given of the dahllite from Mouillac, France, upon which x-ray measurements were made.
The effects of temperature and of heat treatment on Pyrex chemically resistant glass have been studied by measuring the rate of diffusion of helium and of hydrogen through a tube of about one millimeter wall thickness. Measurements were made with helium between 180°C and 590°C, and with hydrogen at 512°C. The influenc…
Measurements were made of the heats of combustion of one artificial graphite, two natural graphites, and two samples of diamond. The bomb calorimeter used was calibrated electrically and by means of benzoic acid. The amount of reaction in each combustion experiment was determined from the mass of carbon dioxide formed…
An apparatus is described which may be used for x-ray diffraction work on substances under pressures up to 5000 atmospheres. The compressive medium is helium gas. A small (2.5 cm radius) Debye-Scherrer type camera is used. The camera, complete with film and specimen, was placed inside the high pressure chamber. The x-…
According to their atomic arrangement the minerals found in clays can be divided into the two-layer and the three-layer structures. The members of the first group have alternating silica and alumina layers, e.g. kaolinite; the members of the second group have one alumina (or magnesium or iron) layer between two silica…
The empirical similarity in the behavior of scattering-factor curves for different atoms is used to replace the structure-factor formulae by an approximating system. This system is shown to lead to $m'\mathrm{th}$ degree algebraic equations, designated fundamental equations, whose coefficients are calculable in terms…
Abstract The theory of paramagnetism, originally developed by Langevin (1905) and extended by Weiss (1907) to include ferromagnetics, led to expressions giving the variation of magnetization with temperature above and below the Curie point. These proved of great value in correlating experimental results, and the gener…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTHE CHEMILUMINESCENCE OF THE CHLOROPHYLLS, AND OF SOME OTHER PORPHYRIN METAL COMPLEX SALTSPaul RothemundCite this: J. Am. Chem. Soc. 1938, 60, 8, 2005Publication Date (Print):August 1, 1938Publication History Published online1 May 2002Published inissue 1 August 1938https://p…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Molecular Structure of Arsenious Oxide, As4O6, Phosphorus Trioxide, P4O6, Phosphorus Pentoxide, P4O10, and Hexamethylenetetramine, (CH2)6N4, by Electron DiffractionG. C. Hampson and A. J. StosickCite this: J. Am. Chem. Soc. 1938, 60, 8, 1814–1822Publication Date (Print):…
A method has been devised for the measurement of the dielectric constant of a material that cannot be made to completely fill a condenser. The following is the procedure adopted: Two completely miscible liquids are so chosen that the dielectric constant of the material under examination lies between the two values for…
A bstract X‐ray diffraction patterns have been made of three samples of soda‐boric oxide glass of the following molal compositions: 0.114 Na 2 O, 0.225 Na 2 O, and 0.333 Na 2 O. The patterns were made in an evacuated camera, using MoK α radiation monochromatic by reflection from rock salt. Radial distribution curves f…
The discharge through flowing vapour of SiCl 4 , SnCl 4 , and SnCl 2 shows a number of regions of selective continuous emission, and, intimately connected with them, several sets of new bands. These appear under conditions unfavourable for the production of the known bands of SiCl and SnCl respectively. They are broad…
The Weiss-Heisenberg theory of ferromagnetism is discussed and generalized in a plausible way. Whether this generalization is theoretically sound must be determined by a quantum-mechanical investigation. The proposed equations of state, however, may be regarded as an attempt to describe antiferromagnetism (i.e., the c…
The methods used to measure separately the electronic and lattice heat conductivities κ e and κ g in a metal are reviewed, and it is pointed out that care is necessary in interpreting the results in view of the underlying assumptions. The equations given by Wilson for κ e and for the electrical conductivity σ are used…