Materials Literature
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Polar structures with pseudosymmetry related to a hypothetical non-polar configuration are considered as good candidates for displacive ferroelectrics. Recently we have developed a procedure for the systematic search of pseudosymmetric structures in the available databases. The aim of the present contribution is the g…
Abstract Poly(5-aminonaphthalene-2-sulfonic acid) 2 can be prepared by oxidative polymerisation of 5- or 8-aminonapthalene-2-sulfonic acid (1a, 1b) with Na2S2O8 or KIO4. This polymer is water soluble, electrically conducting and fluorescent.
A swinging pendulum is arranged to impact and bounce from a fabric sample. The energy losses during impact compression are calculated from the changes in potential energy of the pendulum after allowing for other losses. It is found that the compression energy loss, calculated from the static characteristics, gives onl…
Parallel and perpendicular components of the dielectric constant for 5CB nematic liquid crystal are measured in a relaxation region. Two frequencies f 1 ≈30 and f 2 ≈350 MHz are determined at which the inversion of the dielectric anisotropy sign is observed. It is shown that the observed sizable high-frequency shift o…
We have studied absorption and emission spectra of the ${4f}^{14}\ensuremath{\leftrightarrow}{4f}^{13}5d$ electronic transitions of ${\mathrm{Yb}}^{2+}:({\mathrm{CN}}^{\ensuremath{-}}{)}_{n}$ defect complexes in NaCl, KCl, RbCl, and KBr host crystals under concentration variation of both dopants ${\mathrm{Yb}}^{2+}$ a…
We have studied the electro-optical characteristics of a homogeneously aligned nematic liquid crystal (LC) with weak planar anchoring of the director at the bounding substrates. By using the in-plane switching (IPS) of the LC which is achieved by an in-plane electric field, the driving voltage was confirmed to be far…
In this paper, the Newton-Raphson method, using two-directional (anisotropic) material properties, is applied to the analysis of a three-phase transformer. A new two-dimensional (2-D) model that reflects three-dimensional manufacturing effects, such as air-gap and overlapped stacking, is proposed. These effects cannot…
Covers advancements in spacecraft and tactical and strategic missile systems, including subsystem design and application, mission design and analysis, materials and structures, developments in space sciences, space processing and manufacturing, space operations, and applications of space technologies to other fields.
Abstract Particle shape, angularity, and surface texture are critical properties in assessing aggregate usage for asphalt concrete. Fractured and flat and/or elongated particles are used in most specifications to assure quality. The particle index and uncompacted void tests indirectly measure particle shape, angularit…
Americanae nace como un proyecto conjunto que surge dentro de la Red Europea de Información y Documentación sobre América Latina (REDIAL), y que ha afrontado la Biblioteca de la Agencia Española de Cooperación Internacional para el Desarrollo (AECID). Esta nueva biblioteca virtual hace más accesibles los libros digita…
Smectites including the iron-bearing smectites have proved difficult to measure using the techniques of Raman spectroscopy. The use of Fourier transform (FT)-Raman spectrometers using indium-gallium-arsenide detectors has enabled the spectra of a selection of high iron-bearing smectites and nontronites to be measured.…
Abstract Dynamic fatigue crack growth has been investigated in polyethylenes of various molecular weights and branch concentrations. Square load waveforms were applied to sharply notched samples and the load was adjusted so that for all tests the maximum stress intensity factor was constant and tensile, K max , but di…
We reexamine the recently discovered giant microwave magnetoimpedance in manganite powders. The absorption consists of two components, a resistive part which is only weakly field dependent, and a low-temperature spin-dependent part, which gives rise to the giant effects. We propose that the half-point field H0, requir…
We studied the photoalignment of nematic liquid crystals by examining polyimide, polyester, polystyrene, polyvinylalcohol (PVA), and polymethylmethacrylate (PMMA) exposed to linearly polarized deep UV (LPDUV) light. Polystyrene aligned the liquid crystal parallel to its LPDUV polarization axis, while polyimide and pol…
Plasticizers modify the mechanical properties of polymericmaterials. The effects of plasticizers on glass transition temperatures can be most clearly observed in isochronal temperature sweep profiles of viscoelastic dynamic moduli. However, no simple mathematical models of plasticization are available to those who wis…
Pure hexagonal h, as well as mixed-phase cubic/hexagonal c/h boron nitride (BN) thin films were deposited onto [001] silicon substrates using the dual ion beam deposition technique. The BN thin films were grown under UHV conditions at different substrate temperatures and ion beam bombarding parameters. Thin-film growt…
Abstract Fast Fourier transform infrared (FT-IR) imaging measurements of cured polybutadiene(PBD)/zinc diacrylate(ZDA) showed a heterogeneous distribution of zinc diacrylate. The phase structures were classified as PBD-rich and ZDA-rich domains. Upon curing, the increase in the infrared aliphatic CH stretching mode at…
Wie schon für die homologen La und Ce Verbindungen ergab auch die röntgenographische Strukturbestimmung an Einkristallen von PrTe2, dargestellt durch chemische Transportreaktionen ausgehend von Praseodym und Tellur in Anwesenheit von geringen Mengen an Iod, Überstrukturreflexe, die, wie schon für CeTe2, auf eine (2 ×…
Abstract The pressure-volume-temperature (PVT) melt behavior of 12 polyethylene resins was evaluated at pressures up to 200 MPa, using both isothermal and isobaric measurements in a GNOMIX high pressure dilatometer. The resins included high density polyethylene (HDPE), low density polyethylene (LDPE) and linear low de…
A commercially prepared, hot-dip galvanized, low-carbon steel sheet sample has been studied by means of XPS, SEM, and energy-dispersive x-ray spectroscopy (EDS). The sample was processed in a molten Zn bath containing Al and other additives at low concentrations. Extensive Al segregation to the top of the galvanized l…