Materials Literature
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Soluble alkyl ( II, 8a,b ), fluoroalkyl ( 4a ), and fluoroalkoxy ( 4b,c, 8c ) 1,(4)- or 2,(3)-substituted phthalocyaninato- and linear 2,(3)- and angular 1,(2)-annulated naphthalocyaninatotitanium(IV) oxides 10, 12, and 14 were synthesized and characterized with regard to their spectroscopic, photophysical, and photoc…
The issue “Do trivalent cations conduct in crystalline solids or not?” appears in the basic research of solid-state chemistry and deals with the characteristics and properties of a multivalent cationic current transport through a solid material. Cations in an oxidation state higher than two are not unanimously accepte…
The Fe-O and Fe-N bond lengths at two iron sites of the mixed-valence complex [Fe(3)O(OOCC(CH(3))(3))(6)(C(5)H(5)N)(3)] show a pronounced temperature dependence; the bonds from two of the Fe atoms to the central oxygen atoms vary by more than 0.10 Å on cooling to 10 K whereas the bond from the third iron atom is essen…
Films were prepared by casting alkaline solutions of gliadin, a major wheat storage protein fraction. Their compositions and mechanical and surface properties were analyzed. Five polyols of the ethylene glycol series and glycerol were compared as plasticizers. The plasticized film-forming solutions exhibited viscositi…
Complex transition-metal hydrides provide new opportunities for hydrogen storage. Their hydrogen-to-metal ratios reach values of up to H/M = 4.5 (BaReH9) and thus surpass the hydrogen-to-carbon ratios of hydrocarbons (methane: H/C = 4); their hydrogen-volume efficiencies exceed that of liquid hydrogen by a factor of u…
A method for parametrizing the A cation size disparity or mismatch in ATO 3 perovskites through the A cation size variance has recently been proposed and experimental studies are reviewed. (A is a mixture of trivalent lanthanide and divalent alkaline-earth cations.) The metal−insulator transition temperature in AMnO 3…
Early stages of crystallization of polymers may be viewed as physical gelation. This is shown with four commercial isotactic polypropylenes, which have been studied by dynamic mechanical experiments at low degrees of undercooling, Δ T = 10−26 K, below their nominal melting temperature. The physical gel point is manife…
Using spin density functional theory we have carried out a comparative study of chemical bonding and magnetism in Fe_4N, Fe_3N and Fe_2N. All of these compounds form close packed Fe lattices, while N occupies octahedral interstitial positions. High spin fcc Fe and hypothetical FeN with rock salt structure have been in…
Using numerical self-consistent field (SCF) calculations, we investigate the interactions between two closely spaced surfaces and the surrounding polymer melt. Short chains (surfactants) are terminally anchored to each of the surfaces. The coated substrates model organically modified clay crystallites (sheets). Throug…
Contaminant deposition measurement have been made on species content and depth profiles on three experiment trays from the long duration exposure facility (LDEF), Auger, Argon sputtering, ESCA and SEM analysis was used to define the contaminant deposits. The Integrated Spacecraft Environments Model (ISEM) was used to…
The passive optical sample assembly-I (POSA-I), part of the Mir Environmental Effects Payload (MEEP), was designed to study the combined effects of contamination, atomic oxygen, UV radiation, vacuum, thermal cycling, and other constituents of the space environment on spacecraft materials. The MEEP program is a Phase 1…
A systematic investigation of the effects of stereochemistry and solid-state morphology on emission characteristics were performed using glass-forming pyrenyl and carbazolyl derivatives as neat films in PMMA and cholesteric liquid crystalline glass. At high dilution in tetrahydrofuran, pyrenyl derivatives were prone t…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLinear Trimerization Reaction of Silylacetylene Promoted by GaCl3Yoshiyuki Kido and Masahiko YamaguchiView Author Information Faculty of Pharmaceutical Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan Cite this: J. Org. Chem. 1998, 63, 23, 8086–8087Publication…
The x-ray crystal structures of trans-cinnamoyl-subtilisin, an acyl-enzyme covalent intermediate of the serine protease subtilisin Carlsberg, have been determined to 2.2-A resolution in anhydrous acetonitrile and in water. The cinnamoyl-subtilisin structures are virtually identical in the two solvents. In addition, th…
Thiaminase-I catalyzes the replacement of the thiazole moiety of thiamin with a wide variety of nucleophiles, such as pyridine, aniline, catechols, quinoline, and cysteine. The crystal structure of the enzyme from Bacillus thiaminolyticus was determined at 2.5 A resolution by multiple isomorphous replacement and refin…
We have synthesized and characterized via single-crystal X-ray diffraction methods iron(II), ruthenium(II), and osmium(II) carbonyl derivatives of (1-methylimidazole)(5,10,15,20-tetraphenylporphyrinate) [(5,10,15,20-tetraphenylporphyrinate = TPP)], Fe(TPP)(CO)(1-MeIm)·toluene, Ru(TPP)(CO)(1-MeIm)·chloroform, and Os(TP…
A method was developed to determine the initial peripheral contact angle of sessile drops on solid surfaces from the rate of drop evaporation by using the published precise data of Rowan et al. The constant drop contact radius throughout this stage of evaporation, the initial weight (or volume), the weight decrease by…
Two activated carbons were prepared from olive stones with different degrees of activation and oxidized with a (NH 4 ) 2 S 2 O 8 solution for variable periods of time to introduce different amounts of oxygen surface complexes. Samples so prepared were characterized to know their surface area, porosity, and surface che…
Gold and silver nanorods of diameter 40 and 90 nm and having a variety of aspect ratios (length/diameter) were prepared using the template synthesis approach. After template synthesis, the nanorods were freed from the template membrane and dispersed in either hexafluoro-2-propanol (HFIP) or CHCl 3 . The stability of t…
Pinning phenomena in an incommensurate two-chain model of friction are studied numerically. The pinning effect due to the breaking of analyticity exists in the present model. The pinning behavior is, however, quite different from that for the breaking of analyticity state of the Frenkel-Kontorova model. When the elast…