Nuevas interpretaciones de antiguos conceptos sobre el terreno como soporte de firmes blancos
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Dünnste Kohlenstoff-Folien
Bei der Reduktion von Graphitoxyd in sehr verdünnter alkalischer Suspension entsteht extrem feinlamellarer Kohlenstoff. Die Bestimmung der Dicke der dünnsten Lamellen aus dem Kontrast im Elektronenmikroskop ergab, daß sie nur aus einigen wenigen, z. T. wahrscheinlich nur aus einer einzigen Kohlenstoff-Sechseckschicht…
Thermoelectric Properties of Bismuth-Antimony Alloys
The thermoelectric figure of merit (z), resistivity, and Seebeck coefficient have been measured between 20° and 300°K on single crystals of several alloys in the range from 1% to 40% antimony in bismuth. These materials are semimetals (0 to 5% antimony) or small energy gap intrinsic semiconductors (5 to 40% antimony)…
Far-Infrared Ferroelectric Vibration Mode in SrTiO3
The real and imaginary parts of the dielectric constant of SrTi${\mathrm{O}}_{3}$ have been obtained for the region 2.5 to 3000 ${\mathrm{cm}}^{\ensuremath{-}1}$ from an analysis of the reflectivity. The imaginary part exhibits a very strong peak at 100 ${\mathrm{cm}}^{\ensuremath{-}1}$ at room temperature which shift…
Anomalous Magnetic Moments and Transformations in the Ordered Alloy FeRh
Magnetization and electrical resistivity measurements on an iron-rhodium alloy of approximate composition FeRh, having CsCl-type structure, confirm recent x-ray and neutron diffraction evidence for a first-order antiferromagnetic-ferromagnetic transition at about 350°K. From 350°K down to 77°K, an essentially constant…
Experimental determination of the elastic modulus of crystalline regions in oriented polymers
Abstract The elastic modulus of the crystalline regions in some oriented polymers was determined. An x‐ray diffractometer specially constructed for this purpose was used, and the lattice extension in the direction of the fiber axis was measured under application of a direct load. Usually a meridional reflection was us…
Stress recrystallization of graphite
Abstract Conditions are recorded under which specimens of graphite deposited from pyrolysis of methane are found to incorporate large strain energy. Methods of relieving strains by annealing have been investigated. Recrystallization under suitable constraint can be made to yield graphite of high crystal perfection. Ob…
Approximate Radial Functions for First-Row Transition-Metal Atoms and Ions. I. Inner-Shell, 3d and 4s Atomic Orbitals
Orthogonal radial wave functions of first-row transition-metal atoms and ions for 1s, 2s, 3s, 4s, 2p, 3p, and 3d electrons have been constructed using a minimum set of normalized Slater-type functions. Special attention is given to the 3d orbitals, for which it is necessary to use the ``double-zeta'' form; i.e. two Sl…
Optical Spectrum of the Semiconductor Surface States from Frustrated Total Internal Reflections
Through the use of multiple internal reflection and a modulation of the charge in the surface via the field effect, sufficient sensitivity is obtained to observe absorption of infrared radiation resulting from transitions involving the semiconductor surface states. This offers the possibility of obtaining the optical…
Diffusion of Hydrogen and Deuterium in Fused Quartz
A mass spectrometer was used to record the transfer of hydrogen and deuterium through hollow, thinwalled cylinders of fused quartz over the temperature range of 300–1000°C. Steady-state gas permeation measurements resulted in permeability values which agree well with the literature; however, results of transient exper…
Drift Mobilities of Electrons and Holes and Space-Charge-Limited Currents in Amorphous Selenium Films
The band model has been applied to semiconducting amorphous selenium. Drift mobilities in pure films agreed well with previous results of Spear, and some evidence was obtained that the shallow electron and hole traps were caused by imperfections, with further considerations suggesting that the traps were distributed c…
Stored energy in the graphite of power-producing reactors
Abstract The effects of the atomic displacements produced in graphite by the collisions of fast neutrons are of great importance in the technology of graphite-moderated nuclear power reactors. This paper describes experimental and theoretical work on the stored energy associated with such displacements, the rate of re…
Energy Distribution of Secondary Electrons from Copper-Beryllium Alloy by Bombardment of Positive Ions of Inert Gases. II. Activated Copper-Beryllium
Abstract The distribution curves of the kinetic energis of secondary electrons from the activated copper-beryllium surface impacted by inert gas ions were together with the yield of the secondary electrons, measured by the retarding potential method. The contact potential difference between the ion target (activated c…
Cratering of Lead by Oblique Impacts of Hypervelocity Steel Pellets
The volume and shape of craters produced in lead by the impact of steel pellets at 3 km/sec have been studied as functions of the angle of incidence for angles up to 70° from the normal. It is found that crater volume is linear in the cosine of the angle of incidence, and that it is directly proportional to the kineti…
Indirect Magnetic Exchange Interactions in -Fe2O3and Cr2O3
It is shown that the different antiferromagnetic arrangements of ordered magnetic spins in the identical lattices of α-Fe 2 O 3 and Cr 2 O 3 can be explained by the overlap of suitably directed oxygen p orbitals and the differently populated d orbitals of the Fe 3+ and Cr 3+ ions.
Viscosity Determination of Boron Oxide and Binary Borates
The anomalous behavior of rubidium and cesium borate glass and the boron coordination in alkali borate liquids are discussed. The viscosity‐composition isotherms of rubidium and cesium borates have been found to follow the same trend as those of other alkali borates. For boron oxide at temperatures between 500° and 77…
RARE EARTH CHELATE STABILITY CONSTANTS OF SOME AMINOPOLYCARBOXYLIC ACIDS1
Stability constants of the complexes formed between the rare earths and 1,2-bis-STA2-di-(carboxymethyl)-aminoethoxy!-ethane (EGT A) and 2,2' -bis- STAdi- (carboxymethyl)amino!-diethyl ether (EEDTA) were determined by the polarographic and mercury electrode methods at a temperature of 20 deg and an ionic strength of mu…
Derivation of Anodic Dissolution Curve Of Alloys from those of Metallic Components
A derivation of the polarization curve of alloys from those of the single metallic components is shown. At mixed metallic crystals of irregular lattice distribution the rate of dissolution of the alloy in the active state approaches that of the main metallic component of lowest rate of dissolution within certain limit…
A SPHERICAL SHELL UNDER POINT LOADS AT ITS POLES
A rigorous solution in closed form is obtained of the equations of the linear theory of shells for the case of a spherical shell under point loads at its poles. The solution reduces to a membrane state of stress at some distance from the poles. In the immediate vicinity of the poles, E. Reissner's results for a shallo…
The Preparation and Properties of Some Methoxypyrroles
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Preparation and Properties of Some MethoxypyrrolesHenry. Rapoport and Clyde D. WillsonCite this: J. Am. Chem. Soc. 1962, 84, 4, 630–635Publication Date (Print):February 1, 1962Publication History Published online1 May 2002Published inissue 1 February 1962https://pubs.acs…