Materials Literature
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We have demonstrated the second harmonic of a frequency-tripled Nd:YVO4 laser with 2.5-mW quasi-cw output by using an optically contacted, prism-coupled KBe2BO3F2 crystal. We also achieved the second harmonic with a frequency-doubled single-mode Ti:sapphire laser at 172.5 nm and sum-frequency mixing with a dual-wavele…
An incorporation of 1-benzoyl-3-propylthiourea groups into siliceous mesopores of MCM-41 afforded an ordered material with open porosity. This material was prepared via a two-step modification by attachment of an aminopropyl functionality and its subsequent conversion into a thiourea ligand. About 1.5 mmol/g of 1-benz…
Using ultraviolet photoelectron spectroscopy, we provide direct experimental evidence that di-oxygen species are stable on anionic gold dimer and tetramer clusters at room temperature. The stabilization of molecular oxygen is crucial for the high activities of the low-temperature reactions on gold catalysts.
The correlation between photoluminescence (PL) and structural properties of ZnO crystals has been investigated using fine particles prepared by a precipitation method and subsequent heat treatment. The ZnO particles heat-treated at temperatures less than 600°C exhibited red emission centered at 1.9 eV for a weak light…
A new formalism to calculate electronic states of vacancies in diamond has been developed using many-body techniques.This model is based on prevoius molecular models but does not use configuration interaction and molecular orbital techniques. A generalized Hubbard Hamiltonian which consists of all electron-electron in…
Electrospun poly(glycolide-co-lactide) (PLA10GA90, LA/GA ratio 10/90) biodegradable nanofiber membranes possessed very high surface area to volume ratios and were completely noncrystalline with a relatively lowered glass transition temperature. These characteristics led to very different structure, morphology, and pro…
Two new remendable highly cross-linked polymers, 2ME4F and 2MEP4F, were prepared without solvent. Solid-state NMR (nuclear magnetic resonance) was used to study the thermal reversibility of Diels−Alder (DA) cross-linking, and it was found that DA connections and disconnections of both polymers are thermally reversible…
TiO 2 nanoparticles when subjected to UV irradiation exhibit blue coloration as electrons are stored within the particles. Upon contact with gold nanoparticles, a partial disappearance of the blue color is seen as the stored electrons are transferred from TiO 2 to Au nanoparticles. The charge distribution between the…
The title compound, C12H23N3, was prepared and its crystal structure was determined. The five-membered N—C=C—C=N fragment is planar.
Mesoporous silica particles were modified with LIX-84 (2-hydroxy-5-nonylacetophenome oxime). LIX-84 was attached to the surface of silica via noncovalent forces. The effects of silica particle size, pore size, temperature, and pH on metal-ion-exchange properties were studied to characterize metal ion adsorption proper…
Abstract A semirigid and amorphous commercial liquid‐crystalline copolyester (Rodrun) was filled with mica and calcium carbonate (up to 25 wt %) by direct injection molding. The fillers led to decreases in the processability, as observed by torque increases, but maintained the thermal resistance of Rodrun. The effects…
The results of an electron spectroscopy study carried out on a set of pulsed laser deposited CN x films are reported. A progressive degree of graphitization, deduced from the continuous increase in the sp 2 bond fraction, has been found for x values up to 25%. The mass density values, deduced by a proper treating of b…
Calculations of the spin-dependent electronic structure and enthalpies of formation, ΔH, of the ternary hydrides LaCo5H4, PrCo5H4, and their parent intermetallics are reported. All four compounds are found to be metallic and ferromagnetic. We obtain ΔH(LaCo5H4)=−45.6 kJ/mole H2, ΔH(PrCo5H4)=−39.8 kJ/mole H2, and ΔH(La…
We present the results of the Raman studies on vibrational dynamics and static properties of methylcyclohexane (MCH) and deuterated methylcyclohexane (MCH-d14) in distinct thermodynamic states ranging from normal liquid, undercooled liquid to crystal and glassy states. We have studied the low frequency Raman spectra i…
Abstract Polyurethane dispersions containing phosphate and siloxane groups in the main chain were investigated as possible self‐assembling metal coatings. Improved adhesion of the polymer to the metal was observed because of the formation of an insoluble metal phosphate layer at the metal–coating interface. The neutra…
Abstract The effects of the compatibilization on the toughening of polypropylene (PP) by melt blending with styrene/ethylene‐butylene/styrene triblock copolymer (SEBS) in a twin‐screw extruder were investigated. The compatibilizers used were an SEBS functionalized with maleic anhydride, a PP functionalized with acryli…
Abstract Rice starch was hydrolyzed with hydrochloric acid so that starches would be obtained with different molecular sizes. The derived hydrolyzed starches were carbamated at various reaction times and were grafted with different monomers with a potassium permanganate/citric acid system as an initiator. The newly ta…
Abstract Polyurethane dispersion coatings containing phosphate and siloxane chains were evaluated for their self‐assembling properties for a single‐coating system. Dynamic contact angles (DCAs) and X‐ray photoelectron spectroscopy (XPS) were used to study the coating–air interface. The siloxane chains were the predomi…
Abstract. Grain boundary (GB) wetting phase transitions were studied, for the first time, in Al–Mg polycrystals (Mg contents of 5, 10, 15 and 20 wt.%; temperature range 490–630 ºC). It was observed that above 598 ºC all GBs in the solid Al-rich phase were wetted by a liquid phase. Below 540 ºC no GBs wetted by a liqui…
Abstract The presence of aggregates of CaCO 3 nanoparticles in an isotactic polypropylene matrix processed by extrusion promotes the apparition of residual stresses. These stresses are removed with a thermal treatment of the composite, but a higher molecular orientation is then produced. The chain orientation inside t…