THE USE OF LEAD CITRATE AT HIGH pH AS AN ELECTRON-OPAQUE STAIN IN ELECTRON MICROSCOPY
Aqueous solutions of lead salts (1, 2) and saturated
Materials Literature
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Crystal Structures Adopted by Black Phosphorus at High Pressures
Black phosphorus undergoes two reversible structural transitions at high pressures. The first is to a structure of the type arsenic A7. This structure is transformed to a simple cubic structure at higher pressures. The reversibility between the A7 and simple cubic structures at 111 kilobars indicates that the transiti…
Calcite-Aragonite Equilibrium
Calcite-aragonite equilibrium, determined with an oscillating Griggs-Kennedy squeezer over the range 100 degrees to 575 degrees C, is given by P = 5500 (+/- 500) + 12.6 (+/- 1.5) T where pressure is in bars and temperature is in degrees Celsius. Our new determination agrees with earlier high-temperature work but is si…
Electron Ejection from Metals due to 1- to 10-keV Noble Gas Ion Bombardment. I. Polycrystalline Materials
A method is described which complements present techniques and enables measurements to be made of the secondary electron emission coefficient, $\ensuremath{\gamma}$, for ions on materials for which $\ensuremath{\gamma}$ is difficult or impossible to measure by the "flashing" or heating technique. The method allows ope…
High Temperature Furnace with a Sharp Temperature Gradient
A high temperature furnace with a sharp temperature gradient has been designed and constructed. A maximum temperature gradient of 2550°F/in. was obtained. The versatility of this design may permit many uses in materials research. Its capability of growing a silicon-iron single crystal was demonstrated.
The Relationship between the Loss of Water and Carbon Dioxide from Eggs and the Effect upon Albumen Quality
MANY workers have shown the effectiveness of oiling eggs in maintaining albumen quality and reducing the weight loss. Recently interest has centred upon the various methods of applying the oil and the best time at which it should be applied (Schwall et al., 1961; and Goodwin et al., 1962). Mueller (1958) showed that t…
Determination of Transient Thermal Stresses in a Slab with Temperature-Dependent Viscoelastic Properties
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 John S. Humphreys, Charles J. Martin; Determination of Transient Thermal Stresses in a Slab with…
Determination of Debye temperature of α-iron by X-ray diffraction
The Debye temperature of α-iron at 298°K has been determined from Geiger-counter measurements of the Bragg intensities from a polycrystalline sample (using Mo Kα) and theoretical atomic scattering factors. The value obtained (⪹D = 398 ± 9°K) is somewhat less than the average value (418 ± 4°K) calculated from all the a…
Low‐Temperature Sintering of Uranium Dioxide
Studies of the fabrication of uranium oxide fuel pellets by the low‐temperature sintering of nonstoichiometric oxide are described. Completer reversion to stoichiometric UO 2 in the sintered pellets was attained by two methods: (1) Sintering in a nitrogen atmosphere which contained a small amount of hydrogen and (2) s…
Carbon Black Structure in Rubber
Abstract Some of the properties of carbon blacks in rubber are ascribed to its “structure”. This paper presents results on the sinusoidal dynamic straining of rubber/carbon black vulcanizates over an amplitude range including strains less than 0.1% and suggests that an elucidation of structure effects and the nature o…
Phase Transformations in Uranium at High Pressures
The $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\beta}$, $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$ and the direct $\ensuremath{\alpha}\ensuremath{-}\ensuremath{\gamma}$ phase transformations in uranium have been studied up to 45 kbar at cooling and heating rates of 3-5\ifmmode^\circ\else\textdegree\fi{}C…
Nuclear Spin-Lattice Relaxation in Noncubic or Imperfect Cubic Crystals forI=72 or 92
Detailed calculations of the relaxational behavior of the central resonance line corresponding to transitions between levels $m=\ifmmode\pm\else\textpm\fi{}\frac{1}{2}$ have been made for $I=\frac{7}{2}$ and $I=\frac{9}{2}$ in noncubic or imperfect cubic crystals. The behavior of the central line depends on the relati…
Electrical Conductivity of Graphite
Theoretical calculations are given for the electrical conductivity of graphite in the hexagonal layer planes. The resistivity increases with temperatures as T 1.2 between 25°K and 77°K. In the long wave-length limit, the lattice vibrations of graphite are approximatly grouped into two modes, polarization being in the…
Infra-red spectrum and tetrahedral coordination of lithium in the spinel LiCrGeO4
peer reviewed
Cyclic polyhydroxy ketones. I. Oxidation products of hexahydroxybenzene (benzenehexol)
-benzoquinone, rhodizonic acid, triquinoyl (cyclohexanehexone), croconic acid, and leuconic acid (cyclopentanepentone). Certain derivatives and color tests, as well as infrared and ultraviolet spectra, are reported for their identification.
Zur Chemie der Platinmetalle. V Gleichgewichte mit Ru(f)5 RuO2(f)5 RuO3(g) und RuO4(g)
Abstract Aus Glühdrahtexperimenten, bei denen blanke sowie mit RuO 2 bedeckte Ru‐Drähte in O 2 N 2 ‐Atmosphäre erhitzt wurden, konnte abgeleitet werden, daß die Verflüchtigung des Rutheniums bei Temperaturen ≧ 1200°C im wesentlichen als RuO 3 erfolgt. Mitührungsmessungen bestätigten dieses Ergebnis. Sie zeigten ferne…
Stages of glauconite formation in modern foraminiferal sediments
Abstract Examination of 325 bottom samples taken at 68 stations off the SE. coast of the U. S. by the U. S. Fish and Wildlife Service revealed the common occurrence of glauconite in foraminiferal sands. The glauconite is variable in color and in morphology, ranging from dark greenish-black to greenish-white. The dark…
ALUMINIUM AND IRON PHOSPHATE STUDIES RELATING TO SOILS
Summary The reactions of variscite, AlPO 4 ·2H 2 O, and of strengite, FePO 4 ·2H 2 O, with dilute aqueous solutions have been investigated. Particular attention has been given to the effects of time of reaction, pH of solution, and the solution/solid ratio. Thermodynamic solubility constants are maintained only at low…
Crystal structure of a new form of polyoxymethylene
Abstract A new crystalline form of polyoxymethylene is described with an orthorhombic unit cell, space group P 2 1 2 1 2 1 , and lattice constants a = 4.77 A., b = 7.65 A., c = 3.56 A. The chains are helicoidal with the axis of the helix parallel to c . The period of identity of 3.56 A. comprises two monomeric units a…
Crystal structure studies on the polymorphic forms of nylons 6 and 8 and other even nylons
Abstract Polymorphism present in the even nylons has been accounted for in terms of parallel and antiparallel packing of the polyamide chains. Hydrogen bonding appears to play the most important part in governing chain packing. For example, in the antiparallel structure (alternate chains running in opposite directions…