Materials Literature
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Abstract Electron-probe microanalysis (EPMA) is applicable to rare-earth elements ( REE ) in minerals with relatively high REE concentrations (e.g. hundreds of parts per million). However, given that each of the 14 REE has at least 12 X-ray lines in the L spectrum, finding peak-free regions for background measurement…
Hydrogen involvement in the process of stress corrosion cracking (SCC) of pipelines in a dilute bicarbonate solution was studied. Hydrogen distributions in the steels were determined using secondary ion mass spectrometry (SIMS). Results indicated hydrogen evolved from the solution, then diffused into the steels, and e…
Abstract The structure of a cubic Al 69.5 Pd 23.0 Mn 6.2 Si 1.3 phase, which is referred as a 2/1 approximant of an icosahedral phase, was determined by means of single crystal X-ray structural analysis: space group Pm 3 (No. 200), a = 20.211(2) Å, V = 8255.9(14) Å 3 , Mo K α , ( λ = 0.71069 Å); refined as Al 69.6 Pd…
Adsorption of CH 3 OH on Cu 2 O(111), ZnO(0001), and ZnO(10 1 0) has been investigated with XPS, NEXAFS, variable-energy photoelectron spectroscopy (PES), and SCF-Xα Scattered Wave (SW) molecular orbital calculations. At high coverage (≥25.0L), CH 3 OH is adsorbed as molecular multilayers on all three surfaces. At low…
Relatively strong second-harmonic generation (SHG) was observed in the lyotropic cholesteric phase of the poly(γ-benzyl-L-glutamate-co-γ-methyl L-glutamate) (PBMLG) in benzyl alcohol (BA) with application of an electric field. Using an SHG interferometry technique, we confirmed that the phase of SHG was reversed by re…
This article presents the technique for measuring an amplitude and a profile of a laser-generated stress pulse using a Doppler velocity interferometer velocity interferometer system for any reflector (VISAR). The compressive stress, produced by a laser pulse, moves target’s rear free surface. The velocity of this disp…
Mechanical properties of copper have been studied using effective-medium theory and Molecular-Dynamics simulations. At room temperature we calculate the tensile moduli of systems that are elongated along different crystal orientations. These moduli are in very good agreement with the experimental values, the differenc…
MurA (UDP-GlcNAc enolpyruvyl transferase), the first enzyme in bacterial peptidoglycan biosynthesis, catalyzes the enolpyruvyl transfer from phosphoenolpyruvate (PEP) to the 3'-OH of UDP-GlcNAc by an addition-elimination mechanism that proceeds through a tetrahedral ketal intermediate. The crystal structure of the Cys…
Other| February 01, 1998 Silanol groups in minerals and inorganic compounds Daniel Nyfeler; Daniel Nyfeler Universitaet Bern, Laboratorium fuer Chemische und Mineralogische Kristallographie, Bern, Switzerland Search for other works by this author on: GSW Google Scholar Thomas Armbruster Thomas Armbruster Search for ot…
Charge-state-dependent structural stability of oxygen vacancy in α-quartz is determined by using first-principles total-energy calculations. It is found that neutral and positively charged oxygen vacancies show bistability, and that a spontaneous structural transformation occurs for doubly positively and doubly negati…
We report time-resolved small angle X-ray scattering (SAXS) studies of the structural characteristics of the collapsed state of lysozyme from henegg white (HEL) obtained on initiating refolding by rapidly changing solvent conditions from 8 M to 1.1 M urea at pH 2.9. At this reduced pH the lifetime, of about one second…
The quantum efficiency of the 1.3 μm transition in Pr3+ doped oxyfluoride transparent glass ceramics is measured using a self-calibrating fluorescence ratio technique. The measured value of 8%±1% is much higher than expected for Pr3+ in an oxide glass, and is consistent with the incorporation of the Pr3+ ions into the…
Blend films of a commercial poly(vinyl alcohol) (a-PVA) derived from vinyl acetate and silk fibroin (SF) obtained from degummed silk were prepared by mixing the aqueous solutions of both samples. A plain weave structure was recognized only in the blend films, whereas no structure was found for the superimposed films o…
We extend our previous first-principles theory for perovskite ferroelectric phase transitions to treat also antiferrodistortive phase transitions. Our approach involves construction of a model Hamiltonian from a Taylor expansion, first-principles calculations to determine expansion parameters, and Monte-Carlo simulati…
We carry out a theoretical analysis for the spectra of plasmon polaritons in multiple semiconductor layers arranged in a quasiperiodical fashion. This quasiperiodicity can be of the type of so-called substitutional sequences. They are characterized by the nature of their Fourier spectrum, which can be dense pure point…
The mechanism of the electrical resistivity increase above the Curie temperature TC [so-called positive temperature coefficient of resistivity (PTCR) effect] in BaTi1−x−yNbxMnyO3 ceramics is studied with the temperature-dependent resistivity and electron paramagnetic resonance (EPR) data and the calculated energy leve…
The combination of x-ray Brillouin scattering data with coherent inelastic neutron scattering results in vitreous silica allows us to identify the scattering mechanisms for high-frequency sound waves in the glass. Below one THz, one has resonant scattering from low-frequency vibrations, above one THz Rayleigh scatteri…
Polarization properties of ceria‐based anodes dispersed with nanometer‐sized Ru catalysts, which we developed for medium‐temperature solid oxide fuel cells, were greatly improved by controlling the composition and microstructure. Among samaria‐doped ceria (SDC) anodes with compositions of (0 ≦ x ≦ 0.4) a SDC anode wit…
Nonisothermal electron transport in thin barrier heterostructures is investigated using Monte Carlo techniques. Particular attention is paid to the energy balance in thermionic emission, and the Joule heating in the barrier region. By introducing an energy relaxation length, an equation for the temperature distributio…
A series of styrene- d 8 /4-hydroxystyrene graft and block copolymers has been prepared by “living” radical and anionic techniques for use in interfacial strengthening studies at the polystyrene/poly(2-vinylpyridine), PS/PVP, interface. The following copolymers in which A and B segments represent poly(styrene- d 8 ) a…