Materials Literature
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The total vapor pressure of graphite is calculated as a function of temperature to the harmonic oscillator-rigid rotator approximation. It is assumed that three species (C1, C2, and C3) are present in the gas. The C1 atoms are most prominent in the mixture. C3 molecules are relatively more abundant than C2 diatoms. Th…
Summary Using the electrical resistance as an indicator for ordering it is found that Cu3Au specimens prepared in a state of long-range order and then water quenched from 380°c (8°c below the critical temperature) show an ordering effect at about 100°c. After this has decayed a similar effect is again observed after a…
A description is given of the method used to measure the electrical conductivity of NaCl in steam at steam densities between 0.2 and 0.4 g/cc. Values of the specific and equivalent conductances are tabulated at 378, 383, 388, and 393°C for various NaCl concentrations at different steam densities. Sodium chloride behav…
Ferrites of the system MgO–MnO–Fe2O3 have been investigated, and two new classes of magnetic materials have been developed. One class of ferrite has low losses and shows the Faraday rotation effect at microwave frequencies, which makes it useful in new types of microwave components. A second class of ferrite has a rec…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Cecil E. Hall, Robert L. Weber; Introduction to Electron Microscopy. Am. J. Phys. 1 February 1954…
Ferroelectrics are crystals with pseudosyrmnetric structures of polar symmetry in which the direction of polarity can be reversed by an applied field.They are found when the directed bond system of certain atoms changes with temperature while the ionic character of the structure is still important.If only one kind of…
The rate of dissolution of polycrystalline metallic copper in sulphuric acid solutions has been determined as a function of temperature, oxygen pressure, rotation speed, hydrogen ion concentration, sample area, and corroding solution volume. A typical set of conditions would involve a volume of 500 ml. of air-saturate…
The energy-straggling distribution and the most probable energy loss for 15.7-Mev electrons in Cu is calculated. Corrections for the resonance effect, bremsstrahlung, the polarization effect, and multiple scattering are included. The results are in very satisfactory agreement with recent experiments. The discrepancy i…
Mixtures of magnesia and silicic acid ranging in composition from 0.5 to 2.0 M/S were treated hydrothermally at temperatures of 75° to 350°C. for various periods of time. The reaction solids were examined by differential thermal analysis, X ray, and electron microscopy and analyzed chemically. The intermediate product…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectrolytic Transference Properties of PolyphosphatesFrederick T. Wall and Robert H. DoremusCite this: J. Am. Chem. Soc. 1954, 76, 3, 868–870Publication Date (Print):February 1, 1954Publication History Published online1 May 2002Published inissue 1 February 1954https://pubs.…
The results of previously published investigations into the thermal conductivities of alumina, magnesia, and beryllia by five different methods in different temperature ranges are summarized in the empirical equation k = A/(T − 125) + 8.5 × 10 −36 T 10 , where A = 16.2 for alumina, 18.8 for magnesia, and 55.4 for bery…
The infrared spectra of thin films of H2NOH and D2NOD were obtained at — 78° and — 190°C in the region 4000—500 cm—1. Two distinct types of spectra resulted depending on whether the films were formed at — 78° or at — 190°C. The spectra obtained when the films were formed at — 190°C were characterized by broad overlapp…
An improved convolutional method is used to synthesize theoretical line profiles generated by the joint action of seven instrumental weight functions characteristic of the x-ray spectrometer. These include in addition to the five geometrical factors described in a previous publication: (VI) a so-called misalignment fu…
The surface and interfacial energies in the system Ni‐A1 2 O 3 md Ni‐ZrO 2 were determined at elevated temperatures by means of equilibrium interfacial angle measurements. Coincidental measurements of surface tension and contact angle for iron and iron‐silicon alloys in Al 2 O 3 give values of interfacial energy. Appl…
A method has been developed for producing carbon films suitable for electron microscope specimen supports. Carbon is evaporated on to an extremely soluble substrate, which is dissolved away leaving very thin films.
Abstract ( 1 ) The electrostatic internal energy of a solution of rodlike, ionized polymolecules is calculated by an integration which makes use of the molecular potentials evaluated previously. ( 2 ) The electrostatic free energy is calculated by a charging process for which the reference state is a discharged soluti…
ONE of the challenging new problems which has come into being with the rather sudden outgrowth of the atomic energy industry from the laboratory stage is concerned with the ultimate disposition of the radioactive wastes or by-products of that industry. The splitting of the uranium atom or other fuel used in nuclear ch…
Abstract The phenomenon of swelling is associated with the hydration of clay; however, all clays do not swell when hydrated. Steps in the mechanism of hydration and swelling of different types of clays as observed and interpreted by several investigators and some theories proposed as to the cause of hydration and swel…
The laws of heat flow and methods of measuring thermal conductivity are considered. The effects of crystalline nature, impurities, lattice imperfections, grain boundaries, porosity, mixtures, and temperature on thermal conductivity are discussed. There are insufficient reliable data to assess quantitatively the effect…
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