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Secondary emission by electron bombardment has been measured for single crystals of Ge with $p\ensuremath{-}n$ junctions. Maximum yield was found in the range $\ensuremath{\delta}=1.15\ifmmode\pm\else\textpm\fi{}0.03$, at ${V}_{p}\ensuremath{\approx}500$ volts and room temperature. Increasing temperature decreased the…
Magnetic resonance experiments performed on $\ensuremath{\alpha}{\mathrm{Fe}}_{2}{\mathrm{O}}_{3}$ confirm the existence of a highly anisotropic, weak ferromagnetism which disappears below -15\ifmmode^\circ\else\textdegree\fi{}C. The anisotropy energy has been studied as a function of orientation.
Infrared absorption bands characteristic of the crystal lattice were investigated for germanium and silicon. The absorption was found to be insensitive to lattice imperfections due to impurities (\ensuremath{\sim}${10}^{18}$ ${\mathrm{cm}}^{\ensuremath{-}3}$) and due to disorders (\ensuremath{\sim}${10}^{19}$ ${\mathr…
It is shown that ferroelectric KNb${\mathrm{O}}_{3}$ undergoes another phase transition at -10\ifmmode^\circ\else\textdegree\fi{}C in addition to two phase transitions previously reported at 225\ifmmode^\circ\else\textdegree\fi{} and 435\ifmmode^\circ\else\textdegree\fi{}C. At this lowest phase transition KNb${\mathrm…
Abstract A stabilized halloysite-glycerol complex was studied by electron microscope and electron diffraction techniques. The basal reflection was found to be 10.7 Å by both electron diffraction and X-ray diffraction analyses. Electron micrographs of the expanded lattice (halloysite-glycerol complex) were not differen…
Abstract Examination of the silt and clay fractions of two northern Wisconsin soils, Omega loamy sand of the Brown Podzolic group and Ahmeek loam of the Brown Forest group, revealed considerable quantities of interstratified layer silicates. The two soils contained montmorin, vermiculite, chlorite, and illite both as…
An experimental method of determining the axial forces in power transformers is applied to a transformer constructed so that various tapping arrangements can be set up, and curves are given of the forces which occur with typical methods of tapping concentric windings.It is considered that the simple “residual ampere-t…
The angular correlation of the decay $\ensuremath{\gamma}$ rays from neutral $\ensuremath{\pi}$ mesons produced in the reaction ${\ensuremath{\pi}}^{\ensuremath{-}}+p\ensuremath{\rightarrow}n+{\ensuremath{\pi}}^{0}$ has been measured, using counter techniques. Analysis of the observed correlation function yields a val…
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…