Crystal structure of the defect clathrate Cs8Sn44□2
d3 Sn2 Sn3 Sn2 Sn3 Sn1
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Silicon Carbide Coating by Reactive Pack Cementation—Part I: Silicon Carbide/Silica Interaction
Thermogravimetric analyses (TGAs) of SiC–SiO2 powder mixtures have been carried out at temperatures ranging from 1400 to 1700 °C under an atmospheric pressure of Ar (104 kPa). Correlation with thermodynamic calculations allows us to suggest a reaction path leading to the generation of gaseous silicon oxide [SiO(g)]. T…
Deposition of NiOx thin films by sol–gel technique
High quality NiO x thin films have been prepared by the sol–gel technique following alternative routes to the classic metal alkoxide route. Using nickel (II) diacetate as precursor reagent, a nickel complex was deposited on glass substrates. The nickel complex transforms to NiO x after a heat treatment in air above 25…
Development and Deployment of a Scale Squeeze Enhancer and Oil-Soluble ScaleInhibitor To Avoid Deferred Oil Production Losses During Squeezing Low-WaterCut Wells, North Slope, Alaska
Development and Deployment of a Scale Squeeze Enhancer and Oil-Soluble Scale Inhibitor To Avoid Deferred Oil Production Losses During Squeezing Low-Water Cut Wells, North Slope, Alaska M.M. Jordan; M.M. Jordan NEEC Search for other works by this author on: This Site Google Scholar C.J. Graff; C.J. Graff NEEC Search fo…
Preparation of polyzirconoxane from zirconium oxychloride octahydrate and ethylene glycol as a precursor for zirconia ceramics
An Erratum has been published for this article in Applied Organometallic Chemistry 2001; 15(4):317. The preparation of polyzirconoxanes (EG-PZO) was investigated by a one-pot reaction of zirconium oxychloride octahydrate with ethylene glycol. Triethylamine was added dropwise into a mixture of zirconium oxychloride oct…
Reversible and irreversible magnetization in hybrid magnets
Magnetization reversal was studied in hybrid magnets consisting of ferrite and ribbons of the Magnequench alloy MQP-Q (Nd2Fe14B+α-Fe). Recent studies of demagnetization processes in permanent magnets have used two different methods for determining the reversible magnetization, often arriving at conflicting results. Th…
Low Resolution Structure of the ς54 Transcription Factor Revealed by X-ray Solution Scattering
The sigma54 RNA polymerase holoenzyme functions in enhancer-dependent transcription. The structural organization of the sigma54 subunit of bacterial RNA polymerase in solution is analyzed by synchrotron x-ray scattering. Scattering patterns are collected from the full-length protein and from a large fragment able to b…
Investigation of Sodium Distribution in Phosphate Glasses Using Spin−Echo 23Na NMR
The spatial arrangements of sodium cations for a series of sodium phosphate glasses, x Na 2 O·(100- x )P 2 O 5 ( x ≤ 55), were investigated using 23 Na spin−echo NMR spectroscopy. The spin−echo decay rate is a function of the Na−Na homonuclear dipolar coupling, and is related to the spatial proximity of neighboring Na…
Curvature energy of a focal conic domain with arbitrary eccentricity
The most frequently observed focal conic domains (FCD's) in lamellar phases are those based on confocal paris of ellipse and hyperbola. Experimentally, the eccentricity of the ellipse takes a broad range of values 0</=e<1. We present an analytical expression for the curvature energy of a FCD that is valid in the entir…
Abnormal magnetoresistance effect in self-dopedAg2+δTethin films(δ<~0.25)
We report an abnormal room-temperature magnetoresistance behavior in self-doped ${\mathrm{Ag}}_{2+\ensuremath{\delta}}\mathrm{Te}$ films with Ag doping concentration $\ensuremath{\delta}<~0.25.$ Both positive magnetoresistance and negative magnetoresistance are found with the magnetic field applied along perpendicu…
Bovine Type I Collagen as an Endovascular Stent-Graft Material: Biocompatibility Study in Rabbits
PURPOSE: To study the biocompatibility of a bovine type I collagen preparation as a material for small-vessel stent-grafts in rabbits. MATERIALS AND METHODS: A composite nitinol-collagen endovascular stent-graft with a 4-mm inner diameter was deployed in the abdominal aorta in nine rabbits. Angiography was performed,…
Crystal structure of hexabarium pentacosagermanide, Ba6Ge25
8 3 , = 4, p m = 5.698 g -cm" 3 , Rgt(F) = 0.089, wR(F) = 0.086, =293 .
The structure and physical properties ofin situ composites based on semiflexible thermotropic liquid crystalline copolyesteramide and poly(butylene terephthalate)
Liquid crystalline polymer–poly(butylene terephthalate) (LCP/PBT) blends were prepared by melt mixing. The LCP employed was a thermotropic copolyesteramide based on 30 mol % of p-amino benzoic acid (ABA) and 70 mol % of poly(ethylene terephthalate) (PET). The thermal, dynamic mechanical and rheological properties, mor…
Electron-correlation-originated negative magnetoresistance in a system having a partly flat band
Inspired from an experimentally examined organic conductor, a mechanism for negative magnetoresistance is proposed for repulsively interacting electrons on a lattice whose band dispersion contains a flat portion (a flat bottom below a dispersive part here). When the Fermi level lies in the flat part, the electron corr…
The Urbach rule for the PbO-SiO2 glasses
An analysis is made of the behavior of optical spectra of lead-silicate glasses, with variable lead content near the UV absorption edge, and within the 80–470-K range. A generalized formulation of the modified Urbach rule, applicable to glassy materials within a broad temperature range, is proposed for the interpretat…
First sharp diffraction peak in the fragile liquidCa0.4K0.6(NO3)1.4
Molecular-dynamics simulations of the glass former ${\mathrm{Ca}}_{0.4}{\mathrm{K}}_{0.6}{(\mathrm{N}\mathrm{O}}_{3}{)}_{1.4}$ (CKN) have been performed with a polarizable model for the nitrate ion. Polarization effects in the anion were included with a fluctuating charge model. Comparison of the Ca-Ca partial radial…
FT Surface-Enhanced Raman Evidence of the Oxidative Condensation Reactions of Caffeic Acid in Solution and on Silver Surface
Fourier transform (FT)-Raman spectroscopy and FT surface-enhanced Raman spectroscopy (FT-SERS) are applied for the first time to study the chemical oxidative changes undergone by caffeic acid (CA) in solution and when adsorbed on silver colloids. UV-visible spectroscopy was also applied to follow the polymerization of…
RARE SULFOSALTS FROM VULCANO, AEOLIAN ISLANDS, ITALY. III. WITTITE AND CANNIZZARITE
Wittite and cannizzarite, two rare and structurally related nonstoichiometric sulfosalts belonging to the system Pb‐Bi‐S‐Se, were found together around high-temperature fumaroles at La Fossa crater, Vulcano island, Italy. This occurrence makes a comparative study by different methods possible (scanning electron micros…
The role of residues outside the active site: structural basis for function of C191 mutants of Escherichia coli aspartate aminotransferase
In previous kinetic studies of Escherichia coli aspartate aminotransferase, it was determined that some substitutions of conserved cysteine 191, which is located outside of the active site, altered the kinetic parameters of the enzyme (Gloss,L.M., Spencer,D. E. and Kirsch,J.F., 1996, Protein Struct. Funct. Genet., 24,…
Novel cellulose derivatives. V. Synthesis and thermal properties of esters with trifluoroethoxy acetic acid
Esters of cellulose with trifluoroethoxy acetic acid (TFAA) were prepared in homogeneous phase using a mixed anhydride with p-toluenesulfonic acid. Esters with low degree of substitution (DS), and with DS rising from 0 to 3, had hydrophobic character that prevented the usual association with moisture, which is otherwi…