Materials Literature
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Clays modified with paramagnetic ions have been shown to be effective magnetic resonance imaging contrast agents. The efficacy in part relies on the suspension of the small clay particles in aqueous solution. In this study a series of macromolecules were evaluated as suspending agents for Gd(III) ion exchanged hectori…
The 57Fe Mössbauer spectrum of semiconducting xK2O·(90–x)V2O5· 10Fe2O3 glasses (20⩽x⩽30) consists of a quadrupole doublet peak. The linewidth and the quadrupole splitting decreased gradually after heat treatment at the crystallization temperature, reflecting an increased uniformity of Fe–O bonds and a decreased distor…
Reaction of metallo-2-nitro-5,10,15,20-tetraphenylporphyrins with ‘active-methylene’ compounds (e.g. malonates, malononitriles) in the presence of base gives access to novel cyclopropachlorins or functionalized trans-chlorins (both characterized by X-ray crystallography) by way of a sequential Michael addition and rar…
The solubilities of sulfolane (tetrahydrothiophene 1,1-dioxide, tetramethylene sulfone (TMS)) have been determined experimentally in six solvents, 1-heptyne, tetrahydrofuran, 1,4-dioxane, 1,1,1-trichloroethane, benzene and cyclohexane, by a dynamic method in the temperature range (250 to 301) K. The results have been…
The chemical behaviour of oxotitanium(IV) phthalocyanine (OTiPc) in mixtures of dichloromethane and trihalogenoacetic acids was studied by means of spectroscopic measurements. In dichloromethane–trifluoroacetic acid mixtures, OTiPc was relatively unstable, undergoing gradual decomposition via the radical cation of OTi…
The new compounds Rb 3 Yb 7 Se 12 and CsEr 3 Se 5 have been synthesized through the reaction of elemental rare-earth metal and Se with halide flux at 680 °C. The structures of the compounds were determined by the single-crystal X-ray diffraction method. The structures of CsEr 3 Se 5 and Rb 3 Yb 7 Se 12 are considerabl…
The hydrothermal synthesis, X-ray single crystal structure, magnetic properties, and solid state NMR and infrared spectroscopic data of a new compound, K(VO)(SeO(3))(2)H, are described. K(VO)(SeO(3))(2)H crystallizes in the monoclinic space group P2(1)/m (No. 11), with a = 7.8659(7) Å, b = 10.4298(7) Å, c = 4.0872(7)…
The complicated rhombohedral unit cell of crystalline 03B2-boron containing 105 atoms is a good approximant structure for a quasicrystal. Thus one may wonder if between the amorphous and the crystalline phases of boron, a non-metallic quasi-crystalline phase could exist. In order to examine this possibility and to cha…
Ab initio calculations based on density functional theory and the pseudopotential method have been used to investigate the adsorption of neutral oxygen atoms on terraces and steps on the MgO (100) surface. The calculations include spin polarisation and gradient corrections, and are performed on periodically repeated s…
A carbon dual-microband electrode coated with a poly(aniline)–poly(vinylsulfonate) composite film exhibits an off-to-on switching response when exposed to NADH at Ph 7; the device takes a few minutes to fully switch conductivity and has a linear response for NADH concentration up to ca. 4 mmol dm–3.
The acidity of a series of MHNaY zeolites (M = Li, K, Rb, Cs) has been studied by CO adsorption at low temperature and pyridine desorption at increasing temperature, both followed by IR spectroscopy. It clearly appeared that the Brønsted acidity decreased in the following order: LiHNaY > KHNaY > RbHNaY CsHNaY. Attenti…
The behaviour of several high Miller index crystal surfaces of gold is examined by cyclic voltammetry in 0.01 mol dm–3 perchloric acid solutions. The potentials of zero charge, Eσ= 0, and their temperature coefficients, dEσ= 0/dT for the stepped faces (332), (771), (320) and (410) are determined from a single minimum…
A generally applicable stoichiometric and kinetic model was developed for the polyesterification of unsaturated dicarboxylic acid with diols in the presence of a homogeneous acid catalyst. The model also incorporates, besides the esterification, the cis−trans isomerization and the double-bond saturation reactions. Rat…
Abstract High‐speed photography has been used visually to study the shape, surface, turbulence and behaviour of an underwater oscillating bubble generated by an airgun. The source was a BOLT airgun with a chamber volume of 1.6cu.in., placed in a 0.85m 3 tank at 0.5m depth. Near‐field signatures were also recorded in o…
Porous silicons (PSs) were prepared from a lightly doped (boron; 7 × 10 14 /cm 3 ) crystal silicon (c-Si) wafer by anodization in an aqueous hydrofluoric acid (HF) solution of different concentrations (25−55%). The porosity of these PSs was examined by nitrogen adsorption at 77 K. The relationship between the pore str…
Reactions between model compounds were carried out at high temperatures (150−250 °C) in order to provide a correct simulation of the behavior of hydroxyl and carboxyl polyester chain ends in the presence of triphenyl phosphite (TPP). The reaction between TPP and alcohol (3-phenyl-1-propanol) leads to phenoxy/alkoxy su…
We describe experiments on the spreading of liquid droplets deposited on a (wettable) liquid substrate, when the friction in the droplet dominates. We find that the horizontal radius R increases with the spreading time t like t 0.26 ± 0.02 in the capillary regime ( R < κ - 1, the interfacial capillary length), and lik…
Abstract L‐Isoleucine and the isomorphic amino acids L‐leucine and L‐valine serve as a model system in the examination of the effects of impurities on the purity and morphology of crystals recovered from batch crystallizations. Factors are determined that influence crystal purity and, concomitantly, crystal size and s…
Oxide axial profiles for Zircaloy-4 cladding measured for 17 fuel rods irradiated from 50 to 60 GWD/t in three different pressurized water reactors (PWRs) were studied. Computer simulation of the magnitude and shape of the various profiles involved five contributing interrelated effects: (1) thermal feedback, (2) radi…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTIntramolecular Condensation Reactions of α,ω-Bis(triethoxysilyl)alkanes. Formation of Cyclic DisilsesquioxanesDouglas A. Loy, Joseph P. Carpenter, Sharon A. Myers, Roger A. Assink, James H. Small, John Greaves, and Kenneth J. SheaView Author Information Properties of O…