Materials Literature
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Nd-Fe-B permanent magnets from two different manufacturers were irradiated in the Omega West reactor at Los Alamos National Laboratory, with fast neutrons at temperatures of 426 K (153 degrees C) and 350 K (77 degrees C) to fluences of 5.0*10/sup 16/ N/cm/sup 2/ and 6.1*10/sup 16/ N/cm/sup 2/, respectively. At interva…
Aerobic acetic-acid-producing bacteria can cause the depolarization of a UNS-N08366(1) electrode cathodically polarized to −900 mV vs SCE in a synthetic seawater solution. Formation of a calcareous film and initial settlement of micro-organisms on the electrode surface resulted in decreased current density (CD) as a r…
The motion of the freezing front between a needle-shaped crystal and a supercooled liquid is analyzed for situations where there is forced convection aligned with the crystal axis. It is shown that in the absence of capillary effects the shape of the crystal-melt interface is a paraboloid of revolution, similar to tha…
The interaction of O2, CO2, and H2O with bulk BaO and BaO adlayers adsorbed on W(001) has been examined using ultraviolet photoelectron spectroscopy. H2O reacts with bulk BaO to form Ba(OH)2, while CO2 forms a surface layer of BaCO3. Water and carbon dioxide also react with a (√2×2)R45–BaO monolayer adsorbed on W(001)…
Abstract A series of electrically conducting pyrrole “black” polymers has been prepared by chemical oxidation of pyrrole with a variety of ferric salts. The synthesis and properties of these materials are described and compared with electrochemically‐prepared analogs. Pyrrole “blacks” with strong acid anion “dopants”…
Vanadium dioxide is well known for the semiconductor–metal phase transition at 67 °C which has yielded resistivity changes as high as 105 in single crystals. Our objective is to demonstrate that thin films with high transition resistivity ratios can be deposited at modest substrate temperatures by dc reative sputterin…
Bending strength and Young's modulus of aluminum titanate ceramics at room temperature to 1300°C were examined. Bending strength increased from 62 MPa at room temperature to 280 MPa at 1100°C. Young's modulus also increased, to 99 GPa at 1100°C. These increments were caused by crack healing. In particular, crack cylin…
The composition of muscles by myofiber type is associated with their locomotory or postural functions. In the present study the composition of the hip and thigh musculature of sheep by myofiber types and the differences in their distribution were examined. Myofibers were classified into type I, IIA, and IIB myofibers…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTLuminescence processes in [Tb.cntnd.bpy.bpy.bpy]3+ cryptate: a low-temperature solid-state studyG. Blasse, G. J. Dirksen, N. Sabbatini, S. Perathoner, J. M. Lehn, and B. AlphaCite this: J. Phys. Chem. 1988, 92, 9, 2419–2422Publication Date (Print):May 1, 1988Publication Hist…
Abstract The mechanical properties of a vulcanizate of a blend which comprises both a high-diene rubber such as NR and an ozone-resisting concentration (at least 30 to 40 wt.% of the polymers) of EPDM can be greatly improved if the EPDM is chemically modified by the action of maleic anhydride. The effect of the EPDM m…
Recently a dapF mutant of Escherichia coli lacking the diaminopimelate epimerase was found to have an unusual large LL-diaminopimelic acid (LL-DAP) pool as compared with that of meso-DAP (C. Richaud, W. Higgins, D. Mengin-Lecreulx, and P. Stragier, J. Bacteriol. 169:1454-1459, 1987). In this report, the consequences o…
The authors have measured the room temperature Raman spectrum from porous films on silicon substrates. Data from films on degenerate substrates showed a Raman peak at the frequency expected for bulk silicon together with a peak shifted to lower frequencies. This was interpreted in terms of material having, in general,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSyntheses and magnetic properties of a heteropolyoxotungsten(VI)iron(III) cation and [LFeIII(.mu.-MO4)3FeIIIL] complexes (M = chromium(VI), molybdenum(VI)). Crystal structures of L2Fe2(CrO4)3.cntdot.H2O and [L3Fe3W4O14(OCH3)3](ClO4)2.cntdot.0.5H2O (L = 1,4,7-trimethyl-1,4,7-…
Relaxation of trapped holes that are introduced into silicon dioxide from silicon by the avalanche injection method is studied under various conditions of thermal activation and external electric fields. It is found that the flat band voltage recovery in time follows a universal behavior in that the response at high t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, characterization, and x-ray structure of the ruthenium picnic-basket porphyrinsJames P. Collman, John I. Brauman, Jeffrey P. Fitzgerald, Philip D. Hampton, Yoshinori. Naruta, John W. Sparapany, and James A. IbersCite this: J. Am. Chem. Soc. 1988, 110, 11, 3477–348…
BaTiO3 positive temperature coefficient of resistance (PTCR) specimens were made from commercial BaTiO3 which was mixed with 0.35 mol. % of Ho2O3 to make it semiconducting and 0.07 mol. % of MnCO3. After sintering at 1320 °C the samples were annealed in batches at 1220 °C for various periods between 0 and 5 h. The eff…
Fractoemission is the emission of photons and particles due to the fracture of materials. In this paper we present characteristic intensity versus time measurements of photon emission (phE), electron emission (EE), positive ion emission (PIE), and neutral emission (NE) due to the fracture of fused silica and sodium tr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReactivity of dianionic hexacoordinated silicon complexes toward nucleophiles: a new route to organosilanes from silicaA. Boudin, G. Cerveau, C. Chuit, R. J. P. Corriu, and C. ReyeCite this: Organometallics 1988, 7, 5, 1165–1171Publication Date (Print):May 1, 1988Publication…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTBlend miscibility of bisphenol A polycarbonate and poly(ethylene terephthalate) as studied by solid-state high-resolution carbon-13 NMR spectroscopyP. Mark Henrichs, John Tribone, Dennis J. Massa, and James M. HewittCite this: Macromolecules 1988, 21, 5, 1282–1291Publication…
Abstract The growth and dissolution of oxide layers on silicon has been studied under illumination and in the dark by analyzing current transients at different voltages in solutions of NH 4 F of various concentrations at pH values between 1 and 4.5. When the oxidation rate of the silicon at high enough anodic bias and…