Materials Literature
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Abstract X-ray diffraction patterns of garnierites indicate that most samples resemble serpentine-group minerals or a talc-like mineral, or a mixture of these forms, and give respectively 7 Å and 10 Å basal reflections. From a survey of some 40 garnierites, four of predominantly serpentine type and seven of predominan…
Dynamic yield strengths, compression data under uniaxial shock-wave loading, and sonic velocities at 1 bar are reported for polycrystalline TiB2, SiC, Be4B, Be4B+8 wt% BeO, Be2B, AlB12, TiBe12, and ZrBe13. Hugoniot elastic limits were measured as 86, 80, 74, 77, 65, 87, 53, and 71 kbar, respectively. Evidence of phase…
The uniaxial tensile deformation of a fabric is analysed as a special case of the biaxial theory presented in Part I, and the bending rigidity of the yarn at right angles to the tensile direction is introduced. The structural model presented in Part I is used again to solve the uniaxial case. The biaxial-deformation t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactions of monomeric cobalt-oxygen complexes. I. Thermodynamics of reaction of molecular oxygen with five- and six-coordinate amine complexes of a cobalt porphyrinF. Ann. WalkerCite this: J. Am. Chem. Soc. 1973, 95, 4, 1154–1159Publication Date (Print):February 1, 1973Publ…
The over-all shear deformation, that is, the combined deformation of biaxial tensile and shear deformation is considered generally, and a theory by which the mechanical behaviour of fabrics in this slate can be determined is presented. Experiments are also described that were made to confirm the accuracy of these theo…
Evidence for electronic conduction in the preswitching region of chalcogenide glasses is outlined and discussed in terms of several simple models. Electronic processes likely to contribute to the switching process itself are reviewed and compared, where possible, with the predictions of relevant models from convention…
ABSTRACT The objective of this study is to locate as closely as possible the sites of strontium, magnesium, sodium, and potassium in modern aragonitic corals, specifically whether these cations are adsorbed, or are substituted in the carbonate lattice or are incorporated in organic components. In addition to locating…
PLZT electrooptic ceramics were fabricated by a unique atmosphere sintering technique. The ceramics produced were significantly more transparent than those obtained by ordinary O 2 sintering methods; in fact, they were comparable in transparency to those obtained by hot‐pressing. To achieve good transparency, the powd…
Reviews the contribution that transmission electron microscopy has made to the understanding of the mobility and clustering of point defects in fcc and bcc metals. The first part of the paper considers the nucleation and growth of vacancy clusters in quenched fcc metals. In the second part the complex subject of irrad…
Abstract The lattice vibrations of Mg 2 SiO 4 forsterite single crystal have been studied using infrared and Raman techniques. The site symmetry method allows to study the degeneracy lifting of the silicate ion vibrational levels and to assign the modes of vibration (45 infrared active modes and 36 Raman active modes)…
The effects of temperature [(4-500)\ifmmode^\circ\else\textdegree\fi{}K] and hydrostatic pressure (0-4 kbar) on the static dielectric constants ${\ensuremath{\epsilon}}_{a}$ and ${\ensuremath{\epsilon}}_{c}$ and on the frequencies of the four Raman-active phonons ${B}_{1g}$, ${E}_{g}$, ${A}_{1g}$, and ${B}_{2g}$ of si…
Performance and reliability of amorphous semiconductor devices that deal with the handling of information in the form of switching, modulation, storage, and display are discussed. Structural changes between a disordered and a more ordered state and the concomitant large change in many material properties offer the pos…
The stability of cylindrically symmetrical line disclinations is examined by continum theory calculations and topological arguments, to show that these singularities can almost always be replaced by a continuous structure of lower energy. The calculations are applied to the four basic types of index ± 2 structures. Ex…
The theory of the diffuse scattering by point defects and by defect clusters is reviewed. For a small concentration of statistically distributed point defects the symmetry of the long ranging part of the displacement field and the strength of the defects can be obtained from scattering measurements close to the recipr…
SUMMARY: Staining a marine bacterium with Ruthenium Red and Alcian Blue demonstrated an extracellular, compact acidic polysaccharide layer, which was involved in bacterial adhesion to surfaces. The adhesive substance was present on suspended bacteria and appeared to assist adhesion when they were forced into contact w…
A group of transparent ferroelectric hot‐pressed (Pb 0.92 La 0.08 )‐(Zr 0.65 Ti 0.35 ) 0.98 O 3 specimens with controlled grain size and constant porosity and a group of similar specimens with controlled porosity and constant grain size were prepared. The electrical and optical constants and polarization‐reversal prop…
The structure of alpha -phase potassium nitrate (KNO 3 ) has been determined at room temperature (25 degrees C) and closer to the alpha to beta transition temperature at 100 degrees C, from three-dimensional neutron diffraction data. The present results indicate that the potassium atoms experience small but significan…
The first stages of oxidation of niobium (NbOx) have been studied by electon microscopy. Two phases, called NbOxI and II were detected. A study of NbOz will be published elsewhere. Niobium has been oxidized by a wet argon flow on thin foils or powders, heated at temperatures from 350 up to 400°C. NbOxI, which has the…
The phase diagram and crystal structure of vanadium–deuterium alloys have been studied by means of neutron and X-ray diffraction as well as heat capacity measurements. In addition to a disordered solid solution (α-phase), the following three ordered phases have been found at relatively low temperatures, i.e. a β-phase…
The results of measurements on the conductivity of single crystals of SnS2 in a direction parallel to the c-axis are given. Prior to forming, space charge injection is shown to be the predominant mechanism and subsequently for the formed crystal the relation between current and voltage is I ∝ Un where n may be as high…