Materials Literature
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Using frequency-dependent dielectric susceptibility, we have studied three different types of relaxation phenomena, namely primary (\ensuremath{\alpha}), secondary (\ensuremath{\beta}), and conductivity (c) relaxation, in a sample of 25 vol % benzyl chloride in toluene. The measurement covers ten decades of frequency:…
Neutron diffraction, in conjuction with substitution of deuterium (D) for hydrogen (H), has been used to determine the structure of interlayer water in sodium- and nickel-substituted vermiculites. We have measured the intensities of the (00l) Bragg reflections as a function of relative humidity and H/D content, up to…
The electronic structure of the two-dimensional Penrose lattice is studied by numerical diagonalization of a tight-binding Hamiltonian for finite systems with up to 3571 sites. We have analyzed the smoothness of the energy spectrum and localization behavior of the wave functions by level statistics and a generalized p…
We report a full-band-structure calculation of frequency-dependent second-harmonic generation in odd-period strained [(Si${)}_{\mathit{n}}$/(Ge${)}_{\mathit{n}}$]/Si (001) superlattices for n=1, 3, and 5. We derive sum rules to show that for materials with filled valence bands and empty conduction bands, independent o…
The oxidation rate of silicon small particles prepared by a gas-evaporation method and with diameters ranging from about 20 to 500 nm is investigated by high-resolution transmission electron microscopy. It is found that the oxidation rate of silicon small particles is less than the rate for wafers, and decreases with…
Preisach-type models are suggested for the description of strain hysteresis of magnetostrictive materials. It is pointed out that the strain hysteresis has some peculiar properties in comparison with magnetic hysteresis. These peculiarities of strain hysteresis are discussed in detail along with the identification pro…
A new class of diluted magnetic semiconductor (DMS) based on a III-V semiconductor is reviewed. The new DMS, (In,Mn)As, was made possible by low temperature molecular beam epitaxial growth. Magnetic measurements and x-ray diffraction showed homogeneous incorporation of Mn in the films under certain growth conditions,…
A series of interstitial ternary nitrides R2Fe17N3−δ has been prepared via a gas-solid reaction for R=Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Y. These nitrides have structures related to the Th2Zn17 or Th2Ni17 structures of the R2Fe17 parent compounds, but the unit cell volumes are 6%–7% greater, and the Curie…
We report on x-ray scattering studies of the nematic to smectic-A transition in 4-cyano-4'-octylbiphenyl under nonequilibrium shear-flow conditions. As the transition is approached, the interplay between the viscous frictional and the flow-induced-fluctuation forces on the nematic director leads to a series of regimes…
A detailed self-consistent field theory is used to calculate the properties of end-adsorbed polymer chains, or polymer ‘‘brushes,’’ in equilibrium with a blend of adsorbing B polymer and nonadsorbing A polymer. The brush properties depend on χab, Na/Nb and β, where χab is the Flory interaction parameter characterizing…
X-ray-absorption fine-structure (XAFS) measurements of lead from 10 K through and above the melting transition at 600 K have been carried out. A cumulant expansion analysis provides data on the first four moments of the radial distribution of the first shell, which are used to construct a consistent temperature-depend…
Potential n-type dopants in diamond are investigated via ab initio methods. The well-known distortions around the deep donor N are found to arise from the interaction of the N lone pair with a C dangling bond. P, Li, and Na are all shallow dopants, but their solubilities are muh too low for doping via in-diffusion. Li…
The thermoelectric properties of 28 sintered Si0.8 Ge0.2 alloys, heavily doped with either boron or phosphorus and prepared from powders with median particle sizes ranging from about 1 μm to over 100 μm, have been determined from 300 to 1300 K. The thermal conductivity decreases with decreasing particle size, however,…
Hole mobilities have been measured in vapor deposited films of 1,1-bis(di-4-tolylaminophenyl)cyclohexane (TAPC) and TAPC-doped bisphenol-A-polycarbonate (BPPC). Over an extended range of temperatures, the mobilities decrease with increasing field at low fields. At high fields, a log μ∝E1/2 relationship is observed wit…
Lead titanate (PbTiO 3 ) thin films have been deposited on silicon, platinum-coated silicon and titanium silicide by RF-magnetron sputtering from pressed powder targets. The film structure was investigated by X-ray diffraction and was found to be strongly dependent on substrate temperature. Dielectric properties of th…
The photostimulated luminescence (PSL) and thermally stimulated luminescence (TSL) properties of two new X-ray storage phosphors, Ba 2 B 5 O 9 Br-Eu 2+ and Ba 5 GeO 4 Br 6 -Eu 2+ , are reported and discussed. The PSL measurements show that bromine vacancies act as electron traps and that Eu 2+ is involved in the hole…
(Uploaded by Plazi for the Bat Literature Project) No abstract provided.
Isolation and Structure Elucidation of Ergokonin A and B; Two New Antifungal Sterol Antibiotics from Trichoderma koningii Isolation and structure elucidation by 2D‐NMR spectroscopy of the two new antifungal sterol antibiotics ergokonin A ( 1 ) and B ( 2a ) from Trichoderma koningii are described. The structures of 1 a…
Two-dimensional arrays of mutually coherent optical beams are needed in holographic interconnections for both recording and reading gratings. We analyze the use and limitations of binary phase Fresnel lenses to generate beams for these applications. Two known techniques of ion beam milling and thin film deposition are…
A 4.8 kb DNA-fragment was cloned and sequenced encompassing the structural gene of PFL-deactivase (2.7 kb) and 2 kb of the 5' flanking region that contains the elements for anaerobic induction. A mutant lacking deactivase was shown to require exogenous electron acceptors for anaerobic growth with glucose. This reveale…