Materials Literature
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An apparent activation energy for CO desorption from (100) diamond surfaces exposed to atomic oxygen was determined by thermal desorption spectroscopy performed in ultrahigh vacuum and found to be equal to 45.0 kcal/mol. A minimum potential-energy reaction path was identified by semiempirical quantum chemical calculat…
The effect of hydrogen and oxygen surface termination atoms on the visible luminescence of porous Si was investigated for underlying physical mechanism. Atmospheric thermal treatment up to 1000 °C was carried out to study the functional relationship between the surface coverage and photoluminescence (PL). The results…
Previously, the E. coli cysG gene product had been shown to sequentially methylate uro'gen III to produce precorrin-2, hence it was given the trivial name uro'gen III methylase. We now report that in addition to methylase activity, the CysG protein catalyses both the NAD+ dependent oxidation of precorrin-2 to sirohydr…
We have studied the growth of the wetting layer formed at the surface of a critical mixture of poly(ethylene propylene) and perdeuterated poly(ethylene propylene) during spinodal decomposition. The wavelength of the surface spinodal wave is found to grow as ${\mathit{t}}^{1/3}$ over the entire range of times accessibl…
In this letter we present time resolved measurements of the 3.10 eV (400 nm) photoluminescence in germainum-doped silica. The 3.10 eV band arises from a triplet to singlet transition in a GeO defect. We find that the photoluminescence decays with a time constant of around 100 μs. There is a delay roughly 10 μs in dura…
The whole needle-crystal solution for three-dimensional (3D) dendritic growth is described analytically. Its construction involves the existing 3D selection theory for the tip of the dendrite (M. Ben Amar and E. A. Brener [Phys. Rev. Lett. 71, 589 (1993]) plus matching of the tail to this tip. This is exhibited here.…
We present measurements on a novel power detector which can be used as an ultrasensitive detector of millimeter and submillimeter radiation. The absorbing element consists of a thin film resistor strip which is connected to superconducting electrodes. This device exploits the Andreev reflection of electrons and the we…
The C 1s exciton in diamond is studied by soft x-ray emission excited with high resolution monochromatic photons. A strong phonon sideband of 5 eV wide is observed in the exciton recombination spectrum. With the phonon contribution, the exciton binding energy is estimated to be 1.5 eV. The excited atoms is suggested t…
Hyper-Rayleigh scattering has been used to determine the nonlinear optical properties of a chromophore-containing protein in solution. Because the technique of hyper-Rayleigh scattering allows the measurement of hyperpolarizabilities in an isotropic solution without the application of an electric field, this method is…
A thin optical half-waveplate at 1.55μm, only 14.5μm thick, which is 6.3 times as thin as a zeroth order quartz waveplate, is prepared using fluorinated polyimide. This material has good flexibility, thickness controllability, and high thermal stability. The retardation of the waveplate was retained after annealing at…
Addition of conducting iron and copper particles to XLPE power cable insulation reduced the short term AC breakdown strength from 107 kV/mm to 70 kV/mm and 35 kV/mm, for spherically and irregularly shaped particles respectively. In case of objects containing glass particles, the breakdown strength was reduced to 55 kV…
Large water soluble macromolecules can be confined in all proportions into an electrostatically stabilized surfactant lamellar phase without change of the bilayer thickness. Upon progressive addition of salt, the sample phase separates into a polymer-rich and a surfactant-rich lamellar phase. Indeed, at some particula…
We report on the first molecular beam epitaxial (MBE) growth of CdZnS on (100) GaAs substrates using elemental Zn, Cd, and S sources. Single crystal cubic CdZnS layers lattice matched to GaAs have been successfully prepared. The competition in incorporation between Cd and Zn under different sulfur flux conditions is i…
X-ray absorption fine structure (XAFS) measurements of mixed salts ${\mathrm{Rb}}_{\mathit{x}}$${\mathrm{K}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$Br and ${\mathrm{RbBr}}_{\mathit{y}}$${\mathrm{Cl}}_{1\mathrm{\ensuremath{-}}\mathit{y}}$ at their congruent melting points compositions reveal that their actual structure b…
Evidence of a magnetic-field-induced isotropic-nematic phase transition is presented for a colloidal suspension of monodisperse fd virus, a semiflexible particle with a length-to-diameter ratio of \ensuremath{\sim}140. The dynamics of the phase transition are slow enough to study the unstable portion of the phase diag…
Photoemission and x-ray absorption spectroscopy show that both the conduction and valence bands of porous silicon are shifted relative to the bands for bulk silicon, as expected in the quantum confinement model for the optical properties of porous silicon. The shift in the valence band is larger than the shift in the…
A series of III-V-based magnetic semiconductor heterostructures, p-type (In,Mn)As/(Ga,Al)Sb, has been grown by molecular beam epitaxy. Studies on magnetotransport and magneto-optical properties show that perpendicular ferromagnetic order occurs in the heterostructures with thin (In,Mn)As layers. The origin is discusse…
We have studied, via x-ray scattering, the nematic to smectic-A (NA) translational ordering of the liquid-crystal--forming compound octylcyanobiphenyl (8CB) incorporated into the pores of a silica aerogel. We find that the aerogel dramatically alters 8CB phase behavior, eliminating the NA transition found at T=${\math…
The size dependence of the contribution to the excitonic dephasing rate in semiconductor nanocrystals is clarified for various electron-phonon coupling mechanisms. On the basis of these dependencies, the commonly observed linearly temperature-dependent term of the excitonic dephasing rate and the proportionality of it…
Abstract Blends of poly(vinyl chloride) (PVC) and epoxidized natural rubber (ENR) were prepared by melt‐blending and studied using a Monsanto rheometer, infrared spectrophotometer, and dynamic mechanical analyzer. The PVC/ENR blends were found to be self‐crosslinkable, but immiscible at 25/75, 50/50, and 75/25 blend r…