Materials Literature
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Cyclotella nana Hustedt, a small centric diatom requiring vitamin B 12 , was tested as a potential assay organism for that vitamin. Dose–response curves, measured by optical density and cell count, showed a linear relation between growth and B 12 concentration between 0 and at least 2 μμg/ml of the vitamin. Since the…
Thermal and electrical conductivity measurements have been made between 2 and 90°K on samples of copper containing 0.5, 1 and 2 at. % platinum, of copper containing 2 and 4 at. % silicon, and of silver containing 2 at. % platinum and aluminium respectively. The lattice components of their thermal conductivities are de…
Stress-corrosion cracking has been determined as the cause of failure of carbon steel tanks in agricultural ammonia service. Effects of ammonia contaminants, such as air, water, carbon dioxide, oil, etc. on failure rates were studied. In general, air contamination increased stress-corrosion cracking and water in small…
The results of an experimental study of the temperature and strain-rate dependence of τIII for Cu–Zn alloys are described and interpreted in terms of Seeger's theoretical analysis of τIII. The values of the stacking-fault energy, γ, derived in this way are compared with the estimates of γ for the same alloys obtained…
From theoretical considerations a new clothing parameter, the moisture permeability index, has been developed, which describes the efficiency of fabrics or fabric systems in transferring moisture and its associated latent heat. This index extends the existing "clo" formula, which related dry or nonsweating heat loss t…
The phase diagram for the system Bi 2 O 3 ‐B 2 O 3 has been determined experimentally. The melting point of Bi 2 O 3 has been redetermined as 825° C with an estimated overall uncertainty of about ±3°C, and the molal heat of fusion of Bi 2 O 3 , calculated from the slope of the liquidus curve, is 2050 cal per mole. The…
This paper reports electron paramagnetic resonance data of substitutional ${\mathrm{Gd}}^{3+}$ impurities in the cubic and tetragonal phases of barium and strontium titanates. The pertinent spin Hamiltonian parameters are determined as a function of temperature in these two mentioned phases of both crystals. The tempe…
A theoretical study is made on the nuclear spin relaxation in magnetic crystals near their Curie temperatures. The exchange narrowed hyperfine broadening of the NMR line width is shown to increase due to the slowing down of a certain part of the electron spin fluctuations as the transition point is approached, giving…
Recent calculations of electron energy levels in body-centred cubic transition metals are used to estimate the position of the Fermi surface of non-magnetic chromium. It is shown that almost the whole of this surface is placed so that the introduction of an antiferromagnetic superlattice will lower the electron energy…
The thermal conductivity $K$ of a bulk sample of pyrolytic graphite has been measured from 3 to 300\ifmmode^\circ\else\textdegree\fi{}K both perpendicular and parallel to the $c$ axis. Over the whole temperature range below 100\ifmmode^\circ\else\textdegree\fi{}K the thermal conductivity in both directions appears to…
The crystal structures of α Al 2 O 3 , Ti 2 O 3 , V 2 O 3 , and Cr 2 O 3 have been refined using a least-squares analysis of single-crystal x-ray data. Interatomic distances and bond angles are calculated and compared with those of α Fe 2 O 3 .
An analysis is presented for the absorption corrections necessary for the x-ray analysis of diffraction data from a liquid sample confined within a cylindrical sample cell. The evaluation of necessary absorption integrals has been formulated in a numerical calculus procedure appropriate for a digital computer. The pro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal Conductivity of Heterogeneous Two-Component SystemsR. L. Hamilton and O. K. CrosserCite this: Ind. Eng. Chem. Fundamen. 1962, 1, 3, 187–191Publication Date (Print):August 1, 1962Publication History Published online1 May 2002Published inissue 1 August 1962https://pubs…
Magnetic and electric dipole transitions between levels of the 4fx configuration perturbed by a static crystalline field are treated. The expression obtained for the pure-electronic electric-dipole transition probability involves matrix elements of an even-order unit tensor between the two 4fx states involved in the t…
Abstract The activation polarization required to dissolve 18·8 chromium-nickel stainless steel anodically in 42 wt. % aqueous magnesium chloride solution is reduced by yielding of the metal perpendicular to the direction of dissolution. Yielding at strain rates of about 5% /min or more reduces the activation polarizat…
Abstract In den letzten Jahren sind zahlreiche Ringgerüste mit einer Dreifachbindung studiert worden, so Cycloalkine, Heterocyclen mit Dreifachbindung und speziell das Dehydrobenzol. Bislang ist es noch nicht gelungen, das Dehydrobenzol in Substanz zu fassen; die Möglichkeiten dazu werden dargelegt.
The dynamical behavior of uniformly moving dislocations in anisotropic media is considered for the general case in which the dislocation involves three components of displacement. It is found that both edge and screw dislocations can display an anomalous behavior. It appears that, in general, the force of interaction…
The matrix isolation technique has been extended to allow molecules which are in equilibrium with solids at high temperatures to be trapped and studied at low temperatures. A beam of the hot vapor issuing from a Knudsen cell or a heated surface is premixed with a large excess of argon or xenon just prior to condensati…
The symmetry properties of wave functions in magnetic crystals are discussed in terms of the irreducible representations of magnetic space groups. The specific effects of the magnetic ordering on the crystal eigenstates are found to be of three types: (1) There is a lifting of some eigenfunction degeneracies because t…
The atomic configurations and energies for point defects in copper have been studied theoretically using a classical model. The atoms near the defect are treated explicitly while the remainder of the crystal is treated as an elastic continuum with atoms imbedded in it. A Born-Mayer repulsive force law, $A{e}^{\ensurem…