Materials Literature
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Electronic structure investigations on a broad range of gold compounds, including naked and ligated gold clusters, are reviewed. The calculations have been carried out with a recently introduced relativistic variant of the linear combination of Gaussian-type orbitals density-functional (LCGTO–DF) method which affords…
Long, nanometer-size metallic wires can be synthesized by injection of the conducting melt into nanochannel insulating plates. Large-area arrays of parallel wires 200 nanometers in diameter and 50 micrometers long with a packing density of 5 x 10(8) per square centimeter have been fabricated in this way. When charged,…
The phase transition from an isotropic to a nematic phase for a classical fluid of hard ellipsoids has been studied using a version of a theory originally due to Onsager and by computer simulation. In the proposed form of the Onsager theory for the Helmholtz free energy, both the second and the third virial coefficien…
Abstract NMR, potentiometric, and UV/VIS measurements were run to study the protonation and the In 3+ and Cu 2+ stability constants of 1,4,7,10‐tetraazacyclododecane‐1,4,7‐triacetic acid (do3a, L). The protonation of do3a follows the typical scheme with two high and several low log K H values. Between pH 11 and 13, th…
Abstract The present study deals with the investigation of the desorption of vinyl chloride from various commercial and experimental suspension PVC resins in a laboratory fluidized bed drier simulating an industrial drier. The results show that PVC resins may differ widely in the rate at which the monomer is desorbed.…
Abstract A potential mechanism for part of the production decline observed in the Prudhoe Bay field is siderite (iron carbonate) scale deposition. This laboratory investigation focused on evaluating the effect of the existing downhole scale inhibitor program on the proposed siderite formation damage mechanism. A tube…
Abstract Scale inhibitor "squeeze" treatments are used extensively to control problems with downhole carbonate and sulphate scale formation. The return curve from an adsorption/desorption squeeze is governed by the inhibitor/rock interaction which, in turn, is described by the adsorption isotherm. Several factors, suc…
Bundles of nanotubes were produced by vapor-phase condensation of carbon on highly oriented pyrolytic graphite and analyzed by scanning tunneling microscopy. The bundles are found to have widths between 15 and 50 nm, and up to 200 nm long. They are composed of concentric tubules with 2–4 nm in diameter. Atomic resolut…
We compute phase diagrams for diblock copolymers in the strong-segregation regime as a function of volume fraction \ensuremath{\varphi}. We include the ordered bicontinuous double-diamond (OBDD) phase, which is found to be stable between cylinders and lamellae, consistent with experiment, for \ensuremath{\varphi} (or…
First-order Raman scattering of A 1g and E g modes originating from the antiferrodistortive F 2u soft mode confirms the cubic-tetragonal (O h -D 4h ) phase transition in Sr 0.993 Ca 0.007 TiO 3 , at T 0 =125 K. Within the cubic and the tetragonal phase first-order Raman scattering of the soft ferroelectric F 1u mode (…
Abstract Thermal degradation of polyurethane samples was studied by a thermogravimetric method. The effect of soft‐segment length and soft‐segment concentration on activation energy of the degradation process was measured. Three methods of calculation gave activation energies at different stages of the very complex we…
Feldspars with up to about 45% trivalent cations on M positions were synthesized by heating gels of composition Ca 8−2x Na x La x Al 16 Si 16 O 64 at 1300°C and 1 bar. In the range O 3 this substitution is accompanied by the substitution Ca 2+ + Al 3+ → Na + + Si 4+ . As x increases, the triclinic anorthite structure…
Eine Hohlkugel aus quadratischen VO 5 ‐Pyramiden und PhPO 3 ‐Tetraedern , in deren Innerem ein Chlorid‐Ion eingeschlossen ist, so läßt sich das Anion in 1 beschreiben (Strukturbild rechts). Auf den ersten Blick ähnelt dieses Anion mit seiner kugelförmigen Gestalt bekannten Polyoxoanionen, bei genauerer Betrachtung zei…
The crystal chemistry and thermal behaviour of synthetic hercynite (FeAl 2 O 4 ), a normal spinel, produced both hydrothermally and from sintering oxides at high temperatures, were studied by means of powder XRD and Mossbauer spectroscopy. The samples were annealed at different temperatures under controlled oxygen atm…
The study of the octahedral Fe-Mg substitution in smectites was conducted using clay synthesis at 200°C. Mossbauer data revealed that only ferric iron occurs in synthesized smectites. The studied series is then obviously heterovalent. All synthesized clays were tetrahedrally charged leading to structural formulae vary…
Intercalated layered materials comprising an organic dye and inorganic MPS(3) [where M is either the manganese ion (Mn(2+)) or the cadmium ion (Cd(2+))] phases have been prepared. The intercalation process induces a spontaneous poling, giving rise to an efficiency of 750 times that of urea in second-harmonic generatio…
Compressibility of Polymers Structural Aspects of Influence of High Pressure on Polyethylene Viscoelastic and Deformational Properties of Polymers Under High Pressure PVT Effects in Molecular Dynamics of Polymers Radiation Chemistry of Polymers Under High Pressure Polymerization Under Pressure Reactions of Solid Monom…
This book gives perspective of an exciting area of new and intelligent materials for electroactive sensor applications for microelectronics (and possibly in the nanometer scale) for the twenty-first century.
The kinetics of polycondensation of lactic acid has been investigated. The resuIts showed that in the absence of catalyst the polycondensation proceeds as a third order reaction at 124℃ with 10%～60%conversion:-d[COOH]/dt=1.32×1O-5[COOH]3. In the pres-ence of ca.1%(wt) of a strong acid ion-exchange resin at 120℃and 10%…
The acetal homopolymer is conventionally obtained by the polymerization of formaldehyde, following end capping using acetic anhydride. Asahi Chemical developed a new process to obtain an end-capped polymer during polymerization of highly purified formaldehyde using acetic anhydride as the chain-transfer agent. The use…