Materials Literature
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Organic alloys λ-(BETS) 2 Fe x Ga 1- x Cl 4 show superconductivity only under very high magnetic fields parallel to the conducting layer for x ≥0.47. As x decreases, the field induced superconducting phase shifts towards lower fields and a striking field-induced insulator to superconductor transition is observed below…
The electronic properties of quarter-filled organic materials showing spin-Peierls transition are investigated theoretically. By studying the one-dimensional extended Peierls-Hubbard model analytically as well as numerically, we find that there is a competition between two different spin-Peierls states due to the tetr…
The first EuS nanocrystals were prepared by the reaction of europium metal and H 2 S in liquid ammonia. X-ray diffraction (XRD) patterns and TEM images supported the formation of nanoscaled EuS crystals with average size of 20.4 nm. The nanocrystals showed blue shift compared with previously reported EuS films. The Cu…
Van Hove singularities (VHS) in the density of states of multiwalled carbon nanotubes (MWNTs) have been observed by optical spectroscopy for the first time to the authors' knowledge. Additionally, unexpected visible luminescence has been observed on photoexcitation at 1064 nm. This luminescence is believed to arise fr…
Sintered degenerate n-type PbTe samples with a grain size down to about 0.2 µm were prepared and their thermoelectric properties subsequently measured. Accordingly, the effects of grain size on thermoelectric properties were investigated. For samples with a grain size above ∼0.5 µm, the Seebeck coefficient and thermoe…
Oxygen nonstoichiometry of Ca 3 Co 4 O y was precisely measured by thermogravimetry. Combining the result of thermal decomposition analysis, this compound was found to be expressed as (CoO 2 ) 1.62 (Ca 2 CoO 3-δ ) with δ=0–0.14. The observed oxygen nonstoichiometry in the present system was much larger than those of o…
Dielectric and Piezoelectric Properties of Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 Ternary Ceramic Materials near the Morphotropic Phase Boundary, Hosono, Yasuharu, Yamashita, Yohachi, Sakamoto, Hideya, Ichinose, Noboru
Thermoreversible gels were formed by dissolving a poly(methyl methacrylate)−poly( tert -butyl acrylate)−poly(methyl methacrylate) triblock copolymer in a variety of alcohols, including ethanol, 1-butanol, 2-ethylhexanol, and 1-octanol. The gels exhibit an ideal and reversible solid/liquid transition in each of these s…
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…