Materials Literature
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Highly crystalline MCM-41 with a very narrow pore-size distribution (FWHM=1.5 Å), high surface area (1185 m2 g -1 ), large grain size and thick channel walls (ca. 17 Å) was prepared in alkali-free media. The properties of the product depend on the source and concentration of the reactants, the gel aging time, the temp…
Molecular or polymeric π-electron donors based on the association of tetrathiafulvalene (TTF) with linear π-conjugated systems are reviewed. Two main classes of materials are considered, namely electrogenerated polymers, either conjugated or not, and linearly extended TTF analogues built by insertion of different π-co…
Silanation of the internal pore surface of the mesoporous molecular sieve MCM-41 (40 Å) has yielded ethylenediamine (ED), diethylenetriamine (DET), and ethylenediaminetriacetic acid salt (EDT) functionalized sites. These grafted ligands were used for the preparation of cobalt(II) complexes covalently bound to the MCM-…
Superlattices of self‐assembled Ag nanocrystals have been prepared and the structure analyzed using a combination of techniques. It is shown that the supercrystals are hexagonally close‐packed, attributed to a high proportion of icosahedral and decahedral particles. The Figure (a TEM image of the Ag supercrystals) ill…
Testosterone (17β-hydroxy-4-androsten-3-one) was studied by the semiempirical AM1 and PM3 and ab initio STO-3G*, 3–21G*, and 6–31G* methods. The goals were to compare those methods and to know the electronic structure of the hormone. Full geometry optimization was performed, and two crystal conformers (T1 and T2), and…
Abstract Polyamide, polyester and polyoxymethylene having presently a worldwide sales volume of 2,4 million tons a year are important engineering thermoplastics. Based on their special property profiles they are mainly used in the automotive and electronic industry for high performance functional parts. This contribut…
原子炉の解体に伴い、大量の非放射性コンクリートが発生する。環境への配慮から、このコンクリートを処理して重量比で80 %を占める骨材を回収し、新設の工事等に使用することが期待されている。そこで、コンクリート塊に加熱処理とすりもみ処理を施して骨材を回収することを検討した。 加熱処理が分離した骨材の性能に与える効果は温度が高いほど大きいが、高温になるにしたがって骨材そのものも劣化する。骨材の品質へ与える影響を考慮した効果的な加熱温度は200～500 ℃であった。加熱保持時間の影響は相対的に小さかった。また、300 ℃の加熱を施し、すりもみ効果の卓越したロッドミルおよび攪拌ミルによりそれぞれ30～120分処理したとき、建築工事標準仕様書・…
The radula teeth of the littoral gastropod, Nerita atramentosa, have been analysed using energy dispersive spectrometry. The matrix of the mature major lateral teeth contains sulfur, chlorine, potassium, calcium and magnesium. The teeth are tanned, and additionally hardened by the possession of biomineralised granules…
The Raman spectra of the C=O stretching mode of formamide, N-methylformamide and N,N-dimethylformamide mixed with various solvents were systematically studied as a function of concentration. It was found that the hydrogen bond effect plays an important role in reducing the carbonyl stretching wavenumbers for both isot…
This study investigated the chemical stability of pure gallium in water and saline solutions in order to obtain fundamental knowledge about the corrosion mechanism of gallium-based alloys. A pure gallium plate (99.999%) was suspended in 50 mL of deionized water, 0.01%, 0.1% or 1% NaCl solution at 24 +/- 2 degrees C fo…
Hardness of a molecule has been formulated as an average of a set of terms representing various types of reactivity. Hardness parameters for molecules and bonded atoms have been calculated by the ab initio Hartree-Fock self-consistent field (HF SCF) method. An analysis has been presented of the correlation between the…
It is of great importance to find ways to protect concrete from corrosion, to maintain the concrete structure for a long time. A sulfur-oxidizing bacterium, Thiobacillus thiooxidans, has been known to play a crucial role in concrete corrosion and the concrete supplemented with nickel was resistant to corrosion. To obt…
Abstract
Styrene oxide isomerase (SOI) [EC 5.3.99.7], most probably located in the cell wall, was partially purified from Coiynebacterium sp. AC-5 cells grown in a styrene gas atmospheres. The enzyme catalyzed the isomerization reaction to give phenylacetaldehyde, but did not catalyze its reverse reaction. The optimum pH of th…
Eleven high-alloyed stainless steels (SS) were tested for application in chlorinated seawater. Critical crevice temperatures (CCT) were determined using a potentiostatic test method. Results were evaluated in terms of the critical crevice index (CCI) value of the alloys and compared to results of duplicate specimens i…
Copper self-diffusion has been studied in CuO, Y2Cu2O5 and YBa2Cu3O7–xceramics by the SNMS (secondary neutral mass spectrometry) technique in the temperature range 700–900 °C with the stable isotope63Cu used as a tracer. The lowest diffusion rate and the highest value of activation energy were found for the Y2Cu2O5 ph…
The molecular hyperpolarizabilities, β, of spirolinked push−pull polyenes, where the several 1,4-cyclohexadiene rings linked through the tetrahedral sp 3 carbon atoms and electron-donating and -withdrawing groups were introduced in the terminal 1,4-cyclohexadiene rings, were investigated through the ab initio and INDO…
The kinetics of the absorption of lubricating oils and moisture from air into porous polyimide, as well as the exchange of oil between porous polyimide retainers and oil baths or operating bearings, have been measured. Oil absorption into porous polyimide is much faster than into cotton-phenotic. Water is absorbed by…
Epitaxial and textured ceria films were prepared by conventional electron-beam evaporation on (001) LaAlO3, (11̄02) R-cut sapphire, (001) Au, and (001) Pd substrates using ceramic and metallic sources. Deposition temperature and deposition rate were varied to determine their effects on the formation of the CeO2 films.…
An intermediate in the ethanolysis reactions of MoCl 5 , [MoOCl 3 (EtOH)] 2, has been isolated after the reaction of MoCl 5 with 2 equivalents of EtOH and its crystal structure was determined. Treatment of MoCl 5 with 2.5 equivalents of EtOH and subsequent cooling as well as the reaction of [Cl 2 OMo(µ-OEt) 2 (µ-HOEt)…