Materials Literature
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XAFS measurements (LURE and NSLS) of ${\mathrm{Se}}_{1\ensuremath{-}x}{\mathrm{Te}}_{x}$ glasses have been carried out on both the Se and Te $K$ edges at low and room temperatures. Using a multishell best-fit analysis procedure, we have reconstructed the Se and Te local environment: first-shell intrachain nearest neig…
Organic materials for quadratic nonlinear optics generally follow the basic pattern of strongly dipolar quasi one-dimensional intramolecular charge transfer molecules organized in macroscopic crystalline or statistical polar lattices. This restriction has been lifted by the introduction of the much broader class of mu…
Liquids may be used between the magnetic confined fusion plasma and the first wall of the plasma chamber to reduce the material damage through displacements per atom (dpa) and helium gas production. This could extend the lifetime of the first wall in a magnetic fusion energy (MFE) reactor to a plant lifetime of ~30 yr…
Computer optimization shows that the first-order diffraction efficiency of a lossless-transmission surface-relief grating with a rectangular surface profile can be made very large (~95%) simultaneously for light of TE and TM polarizations incident near the Bragg angle by the proper choice of the fill factor. The case…
We report the ab initio structure solutions of two solvent containing potassium phenoxides by high-resolution powder X-ray diffraction. Both compounds are of interest for the classification of the mechanism of Kolbe-Schmitt type reactions. C(6)H(5)OK.2C(6)H(5)OH crystallizes in space group Abm2, Z = 4, with unit cell…
A new and useful method for obtaining diffraction efficiencies from holograms manufactured practically is presented. Applying the rigorous coupled-wave analysis, we express each difference between the practical and the ideal as a mathematical component that can be easily integrated. In Part 1 the effects due to thickn…
arly use of large scale low pressure chromatography came from developments in Manhattan Project and the fractionation of petroleum distillates and the separation of sugars The development of high performance p rocess ch ro m at ograp hy for industrial or manu fa c t u ri n g applications has steadily evolved over the…
It has been found that, even at levels of magnesium hydroxide too low to impart flame retardancy to polypropylene, the addition of melamine makes it possible to reduce burning time under UL 94 conditions sufficiently to meet the V-2 rating. However, flaming drips still persist, so that a V-0 rating by UL 94 can not be…
The interfacial tension γ between the coexisting isotropic and nematic phases of toluene solutions of poly( n -hexyl isocyanate) (PHIC) was determined as a function of the molecular weight of PHIC by the pendant drop method. The value of γ was almost independent of the molecular weight, in contrast to the theoretical…
We studied the interaction of active molybdenum field emitter arrays with molecular hydrogen and helium. Upon impact with the field emitted electrons, H2 gas introduced into the system undergoes dissociation and ionization. The emitter surface is conditioned through the interaction of the hydrogen atoms and ions with…
The escape length of electrons photoinduced from thin CsI, KI, RbI, NaI, and CsBr evaporated films was measured in the 140–180 nm photon spectral range. Theoretical model predictions of the escape length value are in fair agreement with the experimental results. They vary between 10 and 40 nm, the highest values being…
Ab initio and semiempirical calculations of large cluster models have been performed in order to study water adsorption and dissociation on pure, defective (vacancies) and doped (Li, Na, K, Ca, Fe) MgO (001) surfaces. The geometries of the adsorbed and dissociated molecules have been optimized preparatory to analysis…
This paper involves novel fabrication processes for polycrystalline α‐Al 2 O 3 ‐matrix composite fibers that contain nanosized yttrium aluminum garnet (YAG) particles. Dense α‐Al 2 O 3 /YAG nanocomposite fibers with a fine and homogeneous microstructure can be successfully fabricated via a modified sol‐gel process and…
Recent studies have shown that the measured flash widths from single and multibubble sonoluminescence are in subnanosecond or even picosecond regime. Here, we provide conclusive evidence for the existence of nanosecond multibubble sonoluminescence. This has become possible by our ability to find a medium from which ex…
New octupolar bithiophenic methyl cations belonging to the Crystal Violet family are described (see Figure). The synthesis and electrochemical properties of these cations, which should combine the second-order nonlinear optical properties of Crystal Violet with the electrochemical properties of heterocycles, are repor…
A simple model was developed for the interpretation of results stemming from the XPS analysis of polymer surfaces modified by polyethyleneimine adsorption followed by surface coupling of polysaccharides. Theoretical surface compositions were evaluated from the calculated XPS intensity arising from a layered structure…
Elastic constants of a bulk silicon crystal are calculated using the Monte Carlo (MC) technique in conjunction with an isoenthalpic-isotension-isobaric ensemble (HtN ensemble) and the Stillinger-Weber (SW) potential or one of the Tersoff potentials. This MC method is the counterpart of the Parrinello-Rahman HtN molecu…
The optical properties of cholesteric and chiral smectic-$C$ liquid crystals having a pitch shorter than the light wavelength are studied, both theoretically and experimentally. A particular emphasis is placed on the optical activity. For smectics, the optical rotation is maximum for a tilt angle of $45\ifmmode^\circ\…
The role of ammonium ions in order–disorder ferroelastic, ferroelectric and structural phase transitions was studied in mixed [(NH4)1–x Rb x ]3H(SO4)2 0 < x < 1 crystals by dielectric spectroscopy and ac calorimetry. A new superprotonic phase was detected in compounds with x > 0·6. It was found that small Rb concentra…
Summary Permafrost desiccates and indurates soil horizons. During summer, the perennially frozen ground under the active thawed layer creates confined conditions, Whereas in winter the closed system between the permafrost and the freezing front migrating downwards leads to irreversible changes in the soil structure an…