Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubtle effects in the asymmetric epoxidation: dependence of kinetic resolution efficiency on the monodentate alkoxide ligands of the bystander titanium centerBlaine H. McKee, Thomas H. Kalantar, and K. Barry SharplessCite this: J. Org. Chem. 1991, 56, 25, 6966–6968Publicatio…
The relation between structure and preparation conditions of polyaniline (PANI) was determined using scanning tunneling microscopy in air. The morphology of a PANI film grown with fast cyclic potential scans (20 V/s) was uniform and dense, whereas a film grown with slow scans (50 mV/s) over the same potential range wi…
The nonresonant (pi) -electronic component of (gamma) (- 3(omega) ;(omega) ,(omega) ,(omega) ), (gamma) (pi) , is calculated for all-trans, linear symmetric cyanine, and streptocyanine cations with no double-single bond-length alternation, and for cyanine cations with asymmetric geometries resulting from the artificia…
We report detailed experimental studies of the low-frequency Raman scattering in Na½Bi½TiO3. There is enough evidence in support of the Fm3m space group for the paraelectric cubic phase. A broad central peak is found within the phase transition sequence. We suppose that the dominant role of the central peak in the pha…
Following a major shortage of 99Mo in the 2009–2010 period, concern grew that the aging reactor production facilities needed to be replaced. Most producers were using highly enriched 235U (HEU) as the target material. The Organisation for Economic Co-...Read More
ABSTRACT Active gliding movement over long distances was observed and filmed in the marine pennate diatom Ardissonea (Synedra) crystallina (Agardh) Kütz. Typical speeds measured ca. 1–2 μm‐s −1 . Motion wax often smooth and steady; however, discontinuous jerky motions and rolling movements were common. Motion, was ass…
High resolution electron energy loss spectroscopy (HREELS) was used to characterize formate and acetate species adsorbed on the (100) surface of insulating MgO. Sample charging was eliminated using a low intensity, high energy electron beam and Fourier spectral deconvolution was used to remove phonon-phonon and phonon…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis, reactivity, and characterization of the first donor-stabilized silylene complexes of osmium meso-tetra-p-tolylporphyrin (TTP)Os:SiR2.cntdot.THF (R = Me, Et, iso-Pr) and the molecular structure of (TTP)Os:SiEt2.cntdot.2THFL. Keith Woo, Daniel A. Smith, and Victor G…
Environmental cracking of ductile nickel-base alloys has occurred both in pressurized water reactors (e.g., steam-generator tubing) and boiling water reactor components such as pressure-vessel safe ends, weld butters, and filler metals for joining nickel-base alloys or dissimilar metals, and attachment welding pads on…
Abstract The synthesis and characterization are reported of two new series of structurally isomeric polyacrylates containing the azobenzene moiety spaced away from the backbone by a hexamethylene spacer and substituted in 4‐position with linear alkoxy groups (C 1 C 6 , C 10 ) and with a lateral methyl group in 2′‐ or…
The fracture toughness of chemically vapor‐deposited diamond is estimated by a Vickers indentation method. Freestanding diamond films of 400‐μm thickness are produced with plasma‐enhanced chemical vapor deposition and highly polished for indentation testing. Indentation testing was performed with a microhardness teste…
Abstract The effect of pretreatment with sulfuric acid on several metal oxide catalysts for the title reaction was investigated. TiO2, ZrO2, and Fe2O3 Pretreated with sulfuric acid showed high activity, whereas the activity of Al2O3 was decreased by the treatment.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNovel thermoplastic elastomer triblocks of a soft polyisobutylene midblock connected to two hard PMMA stereocomplex outer blocksJoseph P. Kennedy, Jack L. Price, and Katsuo KoshimuraCite this: Macromolecules 1991, 24, 25, 6567–6571Publication Date (Print):December 1, 1991Pub…
Rigid-rod polyesters with long alkyl side chains, denoted as H-Cn, have been prepared by reacting 1,4-dialkylesters of pyromellitic acid with hydroquinone. The alkyl groups were varied from hexyl (n=6) to octadecyl (n=18). The mesomorphic properties and structure of these polyesters were examined by optical microscopy…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAn approach to organic ferromagnets. Synthesis and characterization of 1-phenyl-1,3-butadiyne polymers having a persistent nitroxide group on the phenyl ringKatsuya Inoue, Noboru Koga, and Hiizu IwamuraCite this: J. Am. Chem. Soc. 1991, 113, 26, 9803–9810Publication Date (Pr…
A new serpin (serine proteinase inhibitor), having antichymotryptic activity, was isolated from silkworm, Bombyx mori, larval hemolymph and was named silkworm antichymotrypsin II (sw-AchyII). Amino-acid-sequence analysis of sw-AchyII revealed that it consisted of 375 amino acids without cysteine or glycosylated residu…
The electrical resistivity of the D${0}_{3}$-type (${\mathrm{Fe}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{V}}_{\mathit{x}}$${)}_{3}$Ga and (${\mathrm{Fe}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Ti}}_{\mathit{x}}$${)}_{3}$Ga alloys has been measured over the temperature range from 4.2 to 1250 K. The temp…
We have purified the enzyme 5,10-methylenetetrahydrofolate dehydrogenase (EC 1.5.1.5) from Escherichia coli to homogeneity by a newly devised procedure. The enzyme has been purified at least 2,000-fold in a 31% yield. The specific activity of the enzyme obtained is 7.4 times greater than any previous preparation from…
Irradiation of Cr(CO) 3 (η 6 ‐1,3,5‐cycloheptatriene) ( 1 ) in the presence of bis(trimethylsilyl)ethyne results in [6 + 2] cycloaddition of the alkyne to the cycloheptatriene ligand, yielding Cr(CO) 3 (η 4:2 ‐7,8‐bis(trimethylsilyl)bicyclo[4.2.1]nona‐2,4,7‐triene} ( 2 , 60% yield, Φ=0.08), which upon oxidative decomp…
The effect of plastic strain on the deformation microstructure has been investigated in polycrystalline copper rolled at room temperature to 5, 10, 20, and 30% reduction in thickness (equivalent strain 0·06–0·42). Results from transmission electron microscopy (TEM) observations show that dense dislocation walls (DDWs)…