Materials Literature
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The conformational behaviour of a series of monohydroxamic acids, p-RC6H4CONR′OH (R = Me, R′= H, Me; R = MeO, R′= H, Me; R = NO2, R′= H), and a series of dihydroxamic acids, (CH2)n(CONR′OH)2(n= 3–8, 10, R′= H and n= 7, R′= Me), in methanol, DMSO and chloroform and in the solid state has been examined using IR and NMR…
Layered niobates K 4 Nb 6 O 17 and KNb 3 O 8 showed bright blue emission at 77 K. The luminescent properties were changed by exchanging potassium ions at interlayers with other cations. The luminescent intensity of NH 4 + -exchanged K 4 Nb 6 O 17 was higher than that of native K 4 Nb 6 O 17 . In contrast, for H + -exc…
Oxygen-17 NMR studies indicated that the hexametalates [MW5O19]n– or their derivatives [(MeO)MW5O18](n–1)–(M = Ti, Zr, V, Nb, Ta, Mo or W) can be obtained by hydrolysis of the appropriate mixture of metal alkoxides in the presence of M′O42–(M′= W or Mo) with remarkable selectivity in some cases, giving a very efficien…
The insulation of the 400 kV transmission lines located in the northeast part of Mexico (Monterrey) have experienced flashover problems due to pollution accumulation. Several actions have been taken to increase reliability (washing, use of RTV coatings, insulators with longer leakage distance, etc.). In order to help…
A systematic survey of zeolites Y containing tris(2,2‘-bipyridine)ruthenium(II) with various levels of loading was undertaken. Almost pure Ru(bpy) 3 2+ was obtained whenever the loading was less than approximately one complex per two supercages. At higher loading an increasing amount of byproducts corresponding formal…
Polarized Raman spectra of a single-domain BaTiO3 crystal were measured over the wavenumber range 100–1600 cm −1. In addition to all the A1 and E fundamental vibrational modes reported previously, three new weak bands at 986, 1204 and 1480 cm−1 in the X(ZZ)Y geometry are observed. Based on the temperature dependence o…
The influence of non-soluble or inert contaminants on the flashover voltage of HV outdoor porcelain insulators is examined. A dynamic arc model, presented earlier for predicting the flashover voltage of porcelain insulators covered with water soluble contaminants, has been modified suitably. The extended model has bee…
The interface between metals and oxides is critical in many technologies, including materials science, microelectronics and catalysis. Recent surface science studies of ultrathin vapour-deposited metal films on well defined surfaces of oxides under clean conditions of ultrahigh vacuum are reviewed. The geometric and e…
Condensation of oxamidrazone with sulfur dichloride in acetonitrile affords 4,4‘-bis(1,2,3,5-dithiadiazolium) dichloride in moderate yield. Reduction of this salt with triphenylantimony yields the diradical 4,4‘-bis(1,2,3,5-dithiadiazolyl) [S 2 N 2 C−CN 2 S 2 ], which has been isolated and characterized in the solid s…
Pulsed versus continuous wave plasma polymerization of perfluorocyclohexane is compared as a function of duty cycle off-time, on-time, and peak power. The chemical composition of the deposited films has been determined by X-ray photoelectron spectroscopy (XPS). A greater retention of the chemical structure associated…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSecond-Harmonic Generation by Spontaneous Self-Poling of Supramolecular Thin Films of an Amylose−Dye Inclusion ComplexOh-Kil Kim, Ling-Siu Choi, He-Yi Zhang, Xue-Hua He, and Yan-Hua ShihView Author Information Chemistry Division, Naval Research Laboratory Washington, D…
Abstract Effects of the rare‐earth ions on some properties of a lithium‐zinc ferrite used in high frequency are described. A set of seven compounds with formula Li 0.3 Zn 0.4 Fe 1.96 R 0.04 O 4 where R Yb, Er, Dy, Tb, Gd, Sm and Ce, were prepared by the classical method. The obtained results reveal that, by introduc…
Viscoelastic properties of model poly(dimethylsiloxane) networks with pendant chains composed of linear molecules of known and uniform molecular weights are studied. It was found that the loss modulus ( G‘‘ ) of these networks depends on the concentration and the molecular weight of the dangling chains. The dependency…
Patterns in the cyanide stretching frequencies have been examined in several series of monometal- and CN - -bridged transition metal complexes. Metal-to-cyanide back-bonding can be identified as a major factor contributing to red shifts of ν CN in monometal complexes. This effect is complicated in cyanide-bridged comp…
Phthalazine adsorbed on colloidal silver surfaces is found to convert photochemically to a product in which the N N bond of the molecule likely breaks to form an adsorbed species resembling an ortho-substituted benzene. The photochemical kinetics was studied using a simple flow cell. The photochemical rate constant wa…
The oxothio polyanions gamma-[SiW(10)M(2)S(2)O(38)](6)(-) (M = Mo(V), W(V)) were obtained through stereospecific addition of the dication [M(2)S(2)O(2)](2+) (M = Mo, W) to the divacant gamma-[SiW(10)O(36)](8)(-) anion in dimethylformamide. These compounds were isolated as crystals and are stable in usual organic solve…
K. Bowden and E. J. Grubbs, Chem. Soc. Rev., 1996, 25, 171 DOI: 10.1039/CS9962500171
Phosphonate additives have important applications both in biomineralization processes and in industrial mineral scale formation. The kinetics of crystal growth of hydroxyapatite (HAP) has been investigated in the presence of seven phosphonate additives: HEDP (hydroxyethylenediphosphonic acid), DETPMP (diethylenetriami…
After intravenous (i.v.) injection, colloidal drug carriers such as liposomes, emulsions, polymeric or solid lipid nanoparticles immediately interact with plasma proteins. The adsorbed plasma protein patterns depend on physico-chemical characteristics of the carriers' surface and are regarded as a key factor for the i…
Five cis-cycloalkenes, with ring sizes 5, 6, 7, 8 and 10, and a cis–trans mixture of cyclododecene have been oxidised by iodosylbenzene using iron(III) or manganese(III) tetra(2,6-dichlorophenyl)porphyrin as catalysts. Both catalysts give very similar product distributions, although the reactions with the manganese po…