Materials Literature
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The compressibilities of the monotellurides of Pr, Sm, Eu, Tm, and Yb and the monoselenide and sulfide of Sm have been investigated to \ensuremath{\sim} 300 kbar using high-pressure $x$-ray-diffraction techniques. SmTe, SmSe, TmTe, and YbTe show abnormal volume changes in the 20-50-, 15-40-, 15-30-, and 150-200-kbar r…
Abstract Transition bands are regions of high lattice distortion which result from inhomogeneous deformation in metals. During annealing of cold-worked metals, nucleation of recrystallization is frequently observed to occur within these bands. An analysis has been made of some of the conditions under which transition…
Widths of photoelectron lines associated with vacancies in core levels immediately below the valence shell are shown to depend on the chemical environment. The width variation is ascribed to change in vacancy lifetime. Valence electron density influences these lifetimes through its effect on Auger transition rates. Co…
The vibrational properties of Si III and Ge III have been studied experimentally using Raman spectroscopy, and theoretically using a simple force-constant model. Si III and Ge III are metastable crystalline phases with large unit cells and distorted tetrahedral bonding.
The crystal structure of meta-nitroaniline, a material which exhibits large nonlinear optical effects, has been determined by single crystal X-ray methods. The arrangement of the molecules found differs from that recently proposed by South gate and Hall (see abstr. A49430 of 1971) on the basis of packing consideration…
Impurity nitrogen in type Ia diamond is known to trap radiation damage centres during annealing. Most of the nitrogen is also known to be present in two forms, labelled A and B from the absorption peaks produced by them in the range 1000-1332 cm -1 . In this paper, the effect of these different forms of nitrogen on th…
A one-electron energy diagram is suggested for magnetite, which is consistent with recent soft-x-ray emission and absorption spectra, cathodoluminescence, and optical-absorption data.Received 22 June 1972DOI:https://doi.org/10.1103/PhysRevLett.29.657©1972 American Physical Society
SUMMARY This paper refers to a case of polymorphism in the desmid Micrasterias laticeps Nordst. It is based on material collected from an artificial pond in the state of São Paulo, Brazil. A detailed examination of almost 400 specimens permitted the authors to give a detailed description of 13 main morphological forms…
The study of the solubility of zinc oxalate is particularly suitable for illustration of the relation between solubility and solubility product because ion pair formation is pronounced and competing side reactions occur.
Abstract On the basis of the diagonalization of the complete ligand field, interelectronic repulsion, spin‐orbit interaction, and Zeeman effect matrices, the magnetic properties have been calculated for the octahedral and tetrahedral d 4 and d 6 electron systems. The calculations were performed according to both the s…
Summary Embreyite is a new mineral that has been found only in old specimens collected at Berezov, Siberia. The composition is Pb 4·97 (CrO 4 ) 2·00 (PO 4 ) 1·91 .0·75H 2 O, or Pb 5 (CrO 4 ) 2 (PO 4 ) 2 . H 2 O based on both wet and electron-probe analyses. Z = I, D meas 6·45, D eale 6·41. Crystals are monoclinic with…
Summary Insizwaite from Waterfall Gorge, Insizwa, is a new mineral with the composition Pt 1·00 Bi 1·35 Sb 0·57 . The name is for the locality and is to be applied to the end member PtBi 2 . The analysed material is an antimonian variety. The mineral is cubic, the unit-cell for the antimonian variety has a 6·625 (2) Å…
Uranium nitride and uranium carbonitride fuel pellets were prepared for irradiation in the Japan Material Testing Reactor. The pellets are 6.9 mm in diameter and 7 mm long, and are of natural and 5% enriched uranium. Uranium nitride powder was prepared from uranium metal via hydride and higher nitride. Uranium carbide…
Abstract The thermal decomposition of ammonium nitrate and associated mixtures in the range 170 to 200 °C has been studied by measuring the rate of evolution of nitrous oxide using a flow system in conjunction with a gas chromatograph enabling measurements to be made at temperatures of practical importance not covered…
The tensile fatigue of a 50-50 viscose-polyester warp yam subjected to cyclic loading has been studied. Yarn loading conditions were selected to closely simulate those occurring on the warp during weaving. By examining the lifetime statistics as a function of gauge length, the existence of a "weakest-link" effect was…
Crystal structures of two hexagonal phases in Cu-Sb alloys have been studied by means of X-ray and electron diffraction as well as electron microscopy. A new long period superstructure with space group P6 3 /mmc is found in the range 16-19 at.% Sb ( ε phase), which is essentially an anti-phase modulation derived from…
Galvanic corrosion It is commonly held that it is the electrochemical potential between two surfaces that is the controlling factor for the rate of corrosion. Table 1.2 in chapter one of this series lists the standard oxidation potentials. However, the difference between the potentials of the two metals plus the diffe…
Abstract The helical structures of poly[( S )‐thiazolidine‐4‐carboxylic acid], in the cis and trans forms, were redetermined by using the new sets of bond angles and bond lengths established by X‐ray diffraction analysis of L ‐thioproline. Calculations of the helical structures of poly‐ L ‐proline and poly[( S )‐oxazo…
Studies are made to investigate the possibility of observing living organs in an electron microscope. An environmental cell is developed, which can be put on an ordinary specimen stage. Microorganisms in pond water are introduced into the environmental cell with water, and observed with a high voltage electron microsc…
Summary To produce a lattice expansion readily detectable by conventional X-ray photographic means in α -irradiated diamond, a dose of order 10 18 α .cm −2 is required. Such a dose could be produced by pitchblende in ∼2 × 10 8 yr. and a previously reported lattice expansion in a natural diamond could therefore have oc…