Materials Literature
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The surface structure of alumina-supported gallium oxide catalysts for selective catalytic reduction of NO by CH 4 was studied. The XPS results showed that Ga atoms were dispersed well over the Al 2 O 3 surface for the samples with Ga 2 O 3 content below monolayer coverage (27 wt %) and that Ga 2 O 3 particles appeare…
X-ray photoelectron spectroscopy (XPS/ESCA) has been employed to investigate pure single crystals and powdered samples of yttrium aluminum garnet, Y 3 Al 5 O 12 (YAG), and YAG crystals doped with several rare earth elements (Ln = Pr, Er, Ho, Tm) and a transition metal (Cr). Core level XPS peak shapes of the main eleme…
Reactions of [M(MeCN) n ][BF 4 ] 2 salts with Bu 4 N(TCNQ) in MeOH yield M(TCNQ) 2 (MeOH) x (M = Mn, 1; Fe, 2; Co, 3; Ni, 4, x = 2−4), and reactions of MnCl 2, FeSO 4 ·7H 2 O, CoSO 4 ·7H 2 O and NiCl 2 ·6H 2 O in H 2 O produce M(TCNQ) 2 (H 2 O) 2 (M = Mn, 5; Fe, 6; Co, 7; Ni, 8 ). Infrared spectroscopy, powder X-ray d…
We study the static screening in a Hubbard-like model using quantum Monte Carlo. We find that the random phase approximation is surprisingly accurate almost up to the Mott transition. We argue that in alkali-doped Fullerenes the Coulomb pseudopotential $μ^\ast$ is not very much reduced by retardation effects. Therefor…
We discuss the problem of trapping and mobilization of nonwetting fluids during immiscible two phase displacement processes in porous media. Capillary desaturation curves give residual saturations as a function of capillary number. Interpreting capillary numbers as the ratio of viscous to capillary forces the breakpoi…
A novel approach to prepare magnetic polymeric nanoparticles by synthesis of the magnetite core and polymeric shell in a single inverse microemulsion is reported. Stable magnetic nanoparticles colloid dispersion with narrow size distribution can thus be produced. The microemulsion seed copolymerization of methacrylic…
Abstract Following an earlier paper (SPE 37274, 1997),1 we have continued to investigate the thermal stability of scale inhibitors for application in high pressure/high temperature (HP/HT) reservoirs. HP/HT reservoirs are currently under development in the North Sea and are characterised by high salinity brines (TDS &…
Abstract The continual need to reduce oil production costs has led Mobil North Sea Limited (MNSL) and TR Oil Services Limited (TROS) to develop a new strategy for maximising the efficiency of scale squeeze treatments on the Beryl Field. The strategy combines the advantages of enhanced precipitation scale inhibitors wi…
Abstract One of the most common methods of preventing downhole and topside mineral scale formation in oilfields is through the use of chemical scale inhibitors. Several aspects of the brine composition may affect the performance of the various scale inhibitors used in oilfield applications. In this paper, we focus on…
Hen egg-white lysozyme dissolved in glycerol containing 1% water was studied by using CD and amide proton exchange monitored by two-dimensional 1H NMR. The far- and near-UV CD spectra of the protein showed that the secondary and tertiary structures of lysozyme in glycerol were similar to those in water. Thermal meltin…
Permalloy (Py:Ni81Fe19) exhibits an anisotropic magnetoresistance (AMR) which is very often used to read magnetic signals from storage devices. Py-films of thickness 20nm were prepared by dc-magnetron sputtering in a magnetic field onto thermally oxidized Si-wafers and annealed ex situ at temperatures up to 1000K in o…
We use computer simulations to study the behavior of atomically sharp and blunted cracks in various f.c.c. metals. The simulations use effective medium potentials which contain many-body interactions. We find that when using potentials representing platinum and gold a sharp crack is stable with respect to the emission…
Photochemical release (uncaging) of bioactive messengers with three-dimensional spatial resolution in light-scattering media would be greatly facilitated if the photolysis could be powered by pairs of IR photons rather than the customary single UV photons. The quadratic dependence on light intensity would confine the…
We examined the effects of the tie-molecule fraction on the yielding behavior of two isotactic polypropylenes, one having little ethylene content and the other as the homopolymer with no ethylene. The tie-molecule fraction of the samples used in this study was controlled by blending ethylene-α-olefin of an α-olefin co…
A new class of thermally robust sol-gel polymers have been prepared from the disilaoxacyclopentane derivative 1 by ring-opening polymerization to form nonshrinking polysiloxanes. This reaction, which does not need solvent or water, can be used for, amongst other things, the encapsulation of an electronic microchip.
A region of broad nonlinear curvature is observed in DSC traces of ABA copolymers during temperature sweeps between the glass transition temperatures of the two principal microphases. This curvature is attributed to a smoothly varying composition profile through the interfacial region lying between microphases. The sh…
The electronic and magnetic states in doped perovskite cobaltites, $(\mathrm{L}\mathrm{a},\mathrm{S}\mathrm{r}){\mathrm{CoO}}_{3},$ are studied in the numerically exact diagonalization method on ${\mathrm{Co}}_{2}{\mathrm{O}}_{11}$ clusters. For realistic parameter values, it is shown that a high spin state and an int…
The dodecameric type II dehydroquinases (DHQases) have an unusual quaternary structure in which four trimeric units are arranged with cubic 23 symmetry. The unfolding and refolding behaviour of the enzymes from Streptomyces coelicolor and Mycobacterium tuberculosis have been studied. Gel-permeation studies show that,…
Aromatic liquid crystalline epoxy resin (LCE) based on naphthalene mesogen was synthesized and cured with aromatic diamines to prepare heat-resistant LCE networks. Diaminodiphenylester (DDE) and diaminodiphenylsulfone (DDS) were used as curing agents. The curing reaction and liquid crystalline phase of LCE were monito…
SCD (spin-singlet charge density) description of electron-hole exchange interaction is shown to provide a bridge among the various traditional ways of description of LT splitting of polarization modes, i.e., the interaction among the induced polarization charge, electron-hole exchange interaction (for excitons), and t…