Materials Literature
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The introduction of rare-earth permanent magnets based on samarium-cobalt in about 1970, and neodymium-iron-boron magnets in the mid-nineteen eighties, has ushered in a new era in hard magnetic materials. This has resulted in a dramatic improvement in permanent magnet performance, with neodymium-iron-boron (Nd 2 Fe 14…
The crystal growth, structure and Raman spectra of the PrxY1−xAl3(BO3)4 (PYAB) single crystals are introduced. The experiments show that the characteristic lattice vibrational spectrum of the PYAB arises mainly from the internal vibrations of the BO3 and AlO6 groups, and that the rigidity of the lattice is mainly ascr…
We have used atomistic molecular-dynamics simulations to model the detailed molecular configuration of 5CB (4-n-pentyl-4'-cyanobiphenyl) molecules in the form of a nanoscopic liquid crystal droplet in a vacuum microgravity environment. We find the equilibrium state of droplets consisting of as few as 26 or 50 molecule…
Plates of polyethylene with ultrahigh molecular weight (PEUHMW) were treated by radiofrequency capacitive CF4 plasma discharge in order to incorporate fluorinated functional groups. The consequences of subsequent heating treatments after fluorination were investigated by the combined use of angle-resolved XPS characte…
The tetragonality of small zirconia particles has been established by accurately measuring the tetragonality ratio ( c/a ) of decomposed zirconyl hydroxide, which was then calcined over a range of temperatures to produce a range of average‐sized zirconia crystallite particles. The zirconia initially crystallized as a…
Abstract Remarkable luminescence of neodymium ion (Nd(III)) complexed with 8-quinolinol derivatives containing halogen atoms was successfully observed in organic solution under visible light irradiation via photosensitization. Introduction of halogen atoms in the ligands led to enhancement of the luminescence.
The vulcanization of carboxylated nitrile rubber (XNBR) with zinc peroxide, which produces ionic crosslinks, has been studied in relation to vulcanization time. Vulcanized compounds present two transitions, corresponding to the glass transition of the polymer at low temperatures and the ionic transition resulting from…
The development of several unique characteristics of volcanic soils is not yet as fully understood as the influence of topography on the pedogenesis of such soils. This study was conducted to explain the pedogenesis of consolidated volcanic rocks along a southeastern aspect of toposequence in the subtropical region of…
The present work aims at determining the dependence of the DC insulation resistivity on temperature and electric field for a super-clean low density polyethylene (LDPE) used in manufacturing modern high voltage AC cables. Resistivity measurements were made using relatively thick (/spl sim/2 mm) samples at different te…
The initial stages of Al(111) oxidation by oxygen were investigated by using x-ray photoelectron spectroscopy (XPS) and high resolution electron energy loss spectroscopy. It was found that surfaces exhibiting no impurities from the Auger electron spectroscopy and low-energy electron diffraction data may show different…
Blends of cellulose (CELL) with polyethylene glycol (PEG) were prepared from a mixed solution in dimethyl sulfoxide (DMSO)-paraformaldehyde (PF) by coagulation in a nonsolvent. The state of miscibility of the blends obtained over the composition range of 95/5 to 30/70 was characterized by wide-angle X-ray diffraction…
The redox processes of hexacyanoferrate doping anions inside thick poly(pyrrole) (PPy) layers are considered to be linked to the oxidation state of the PPy. Charge compensation of the PPy can be provided by the influx/efflux of anions and cations or through the Fe(CN)63–/4– oxidation level. In addition it has been pro…
F(2) excimer-laser irradiation induces two major changes in SiO(2): OH glass impregnated with H(2) molecules. First, the vacuum-UV optical absorption edge is bleached, and the absorption at 157 nm decreases from 0.95 to 0.68 cm(-1) . Second, preexisting free SiOH groups and interstitial H(2) are photochemically conver…
Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Verena Ziegler, Bernhard A. Wolf; Viscosity and morphology of the two-phase system PDMS/P(DMS-ran…
Pr3+ doped oxyfluoroborate glasses have been prepared with different concentrations of Pr. The absorption, fluorescence, and photoacoustic spectra have been recorded and lifetimes of some levels were measured. The fluorescence decays were found to be non-exponential for the 3P0 level. Fluorescence quenching was observ…
The corrosion behavior of 304 stainless steel was characterized with cyclic voltammetry in a eutectic Li/K and Li/Na carbonate melt under anode and cathode gas of the molten‐carbonate fuel cell (MCFC). The corrosion rate of 304 steel was determined in four different environments of the MCFC with electrochemical method…
The Al2O3-ZrO2 composite was studied by impedance spectroscopy, a non destructive technique that was found to be sensitive to the composite's microstructure. The observed decrease in the zirconia grain and grain boundary conductivities points to compression on zirconia grain by alumina matrix. This effect increased wi…
The notation of crystallography in arbitrary dimensions is considered. Recommended symbols for point-group transformations, geometric crystal classes, families and systems are presented.
The liquidcrystalline thermotropic behaviour of a series of long alkyl chain dimethylammonioalkoxydicyanoethenolates of the type CH3-(CH2)n-1-N+(CH3)2-(CH2)p-O-CO-C-(CN)2 (n=10-18, even values only, with p=2, 3; p=4 for n=16) was analysed through differential scanning calorimetry, X-ray diffraction and polarizing opti…
The syntheses and crystallographic characterization of the linear trinuclear complex [Mo(3)O(4)(TPP)(3)]ClO(4) and the monomeric precursors [MoO(TPP)(OClO(3))] and [MoO(TPP)(OH(2))]ClO(4) are described. The crystallographic analyses of [MoO(TPP)(OClO(3))] and [MoO(TPP)(OH(2))]ClO(4) show that these similar complexes a…