Materials Literature
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Software has been developed which applies group-theoretical methods to the calculation of phonon spectra. The software draws on a large data base which includes information on each of the 230 crystallographic space groups and their irreducible representations. The software finds the optimal phonon modes for the frozen…
The pyroelectric properties of ferroelectric liquid crystal (FLC) cells possessing helical and surface stabilized structures have been investigated. Pyroelectric properties of a FLC cell depend on the applied voltage, the internal smectic layer structure, and the ratio of the cell thickness to the material pitch d/p0.…
We study radially symmetric stationary points of the functional where u denotes the density of a fluid confined to a container Ω, W(u) is the course-grain free energy and ε accounts for surface energy. Under the further assumption of small energy, that is for small ε, we prove existence of precisely two solutions for…
An x-ray diffraction study was carried out on the crystal structure of the high pressure phases of bismuth, Bi III, Bi III′, and Bi IV, using high-energy monochromatic synchrotron radiation from the TRISTAN Accumulation Ring (6.5 GeV). Powdered samples were compressed in a cubic-type multianvil press MAX80 at pressure…
A homologous series of 1,2,4,5-tetra-(4-alkoxybenzoyloxy)benzenes (2, R = C4H9. C6H13 to C16H33 and C18H37) has been synthesised. Optical microscopy revealed that the compounds with R = C4H9, C6H13 to C10H21 have a nematic phase, compounds with R = C11H23 to C14H29 have nematic and smectic C phases and compounds with…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStatic Polycrystalline Magnetic Susceptibility and Four-Probe Single-Crystal Conductivity Studies of [Ru(bpy)3]0Michael J. Wagner, James L. Dye, Eduardo Perez-Cordero, Rosanna Buigas, and Luis EchegoyenCite this: J. Am. Chem. Soc. 1995, 117, 4, 1318–1323Publication Date (Pri…
A measurement system that simultaneously digitizes acoustic emission pulses in stress-corrosion cracking processes and gauges the electrical resistance variations caused by crack growth has been developed. This tool has allowed us to study the relation between the magnitudes measured by the two systems in stress-corro…
The mechanical properties (yield strength, hardness, transformation stresses) and the transformation temperatures of SMA can be affected by the combination of different solid-state reactions. In this context the combination of local change in chemical composition by precipitation processes and the rearrangement of def…
A large series of thin film transistor compatible nematic liquid crystals incorporating a 2,6-difluorophenyl acetylene group have been synthesised. Most of them exhibit high clearing points and an increased dielectric anisotropy.
Abstract Rheological properties of a high‐density polyethylene (HDPE) subjected to thermal‐mechanical degradation were compared with those of the HDPE degraded by the addition of small quantities of peroxides as free radical initiator. The high molecular weight fraction of HDPE changes quantitatively during processing…
The craze formation and failure typical of many glassy polymers have been investigated using an elastic spring network to model both bulk and crazed polymer material. The elastic properties of the network springs were modified, using simple rules, to capture the hulk polymer to crazed material deformation and the subs…
In this paper a method is presented that allows the characterization of Young’s modulus behavior of the polyurethane foam frame. This parameter has been evaluated according to a technique based on the measurement of the dynamic mass of a cylindrical sample in a rough vacuum. In the approximate temperature range 20 to…
Abstract Two dinuclear manganese(II) complexes, [Mn2(Ph2MeCCOO)3(bpy)2](PF6) (1) and [Mn2(C6H5COO)3(CH3OH)(bpy)2](NO3) (2), have been prepared. X-Ray structural analyses have revealed that complexes 1 and 2 have a different bridging mode in triple carboxylato-bridges between two manganese(II) ions each other.
The effect of the preparation conditions for amorphous including aniline on its discharge and charge characteristics as a cathode material for a rechargeable lithium battery was investigated to improve the discharge and charge characteristics. The was prepared in solutions containing different concentrations of anilin…
Silicon‐based structural ceramics , such as silicon carbide, silicon nitride and SiAlON exhibit an attractive range of properties, i.e. high strength, stiffness, and good wear and corrosion resistance, and are considered very appropriate materials for high‐temperature applications. Recent progress in the synthesis of…
Abstract Der elektrochemische Test zur Bestimmung des Bedeckungsgrades von phosphatiertem Stahl [1] wird auf verzinkten Stahl übertragen. Der Bedeckungsgrad wird aus Stromdichte‐Potentialmessungen, Kapazitäts‐sowie Impedanzmessungen bestimmt. Die freie Metalloberfläche nimmt bei elektrolytisch verzinktem Stahl nach 60…
Both KNbO3 and BaTiO3 systems, in their cubic, tetragonal or orthorhombic phases, were reported to show two-dimensional (2D) diffuse scattering intensity sheets in the reciprocal space, thus indicating the presence of one-dimensional correlation in the real space. Two models have been proposed to explain the origin of…
Transformation sequences in a NiTi shape memory alloy after deformation and subsequent annealing were studied using various methods. Low temperature annealing of the deformed alloy caused that the R-phase preceeded the martensitic transformation. The R-phase formation during both cooling and heating depends strongly o…
Abstract We report scanning Auger microscopy (SAM) and x‐ray photoemission spectroscopy (XPS) analysis of a Roman lead pipe ‘flstula’, the main emphasis being placed on the comparison between the surface and interface chemical composition of the joint and of the rest of the pipe. We find that the ‘tertiarium,’ a Pb–Sn…
The Structure of Semiconductors. The Technology of Semiconductor Devices. The Assessment of Semiconductors by Electrical Techniques. The Assessment of Semiconductors by Diffraction. Optical Assessment of Semiconductors. Assessment of Semiconductors by Ion Beam Techniques. Assessment of Microscopy and Imaging.