Materials Literature
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The rates for nucleation ( I ) and crystal growth ( U ) for a lithium disilicate (Li 2 O·2SiO 2 , LS 2 ) glass were determined, as a function of temperature, using a new differential thermal analysis (DTA) technique. This technique requires in situ nucleation and crystal‐growth heat treatment of a small amount of powd…
CeO 2 ultrafine particles were prepared by solid‐state reactions at room temperature. These particles were found to have very fine particle sizes (∼3 nm) with a fluorite structure ( a = 5.42 Å). BET measurements showed that the surface area of the particles was 96.2 m 2 /g. The use of two different precursors was foun…
We describe a microfabrication process for fabricating micropolarizer devices with polarization thin film. The polarization film is less than a 0.5 microm thick and can have a polarization extinction ratio of approximately 330 in the visible wavelength range. A single-state micropolarizer array with polarizing pixels…
AbstractThe effects of partial substitution of tungsten for molybdenum on the microstructure and impact properties in 22Cr–5Ni–3Mo (wt-%) duplex stainless steel (DSS) have been investigated following aging heat treatments in the temperature range 600–1000°C. During aging the intermetallic σ and χ phases were precipita…
The gene encoding the phosphoglycerate kinase (PGK) from the Antarctic Pseudomonas sp. TACII18 has been cloned and found to be inserted between the genes encoding for glyceraldhyde-3-phosphate dehydrogenase and fructose aldolase. The His-tagged and the native recombinant PGK from the psychrophilic Pseudomonas were exp…
Neutron-diffraction, magnetic and transport measurements, and M\"ossbauer spectroscopy have been used in order to study the structural and magnetic changes of the magnetoresistive ${\mathrm{La}}_{0.7}{\mathrm{Pb}}_{0.3}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Fe}}_{x}{\mathrm{O}}_{3}$ $(x=0,$ 0.05, 0.1, 0.2, 0.3) pero…
This paper presents a dynamic model allowing the prediction of discharge activity leading to flashover of polluted insulators. It takes into account the instantaneous changes of the discharge (arc) parameters. For a given voltage, geometry and pollution severity, the model enables one to determine the following parame…
Abstract The work described in this paper deals with the preparation and the characterization of an homogeneous composite material composed of electrically conductive fillers dispersed in a thermoplastic insulating matrix. These fillers were chosen to have either a spherical shape or a high aspect ratio. Processing of…
[1]Silaferrocenophanes fcSiMe 2 ( 1 ) and fcSi(CH 2 ) 3 ( 3 ) (fc = Fe(η 5 -C 5 H 4 ) 2 ) were incorporated into the well-ordered, hexagonal channels of mesoporous silica (MCM-41). Characterization of the composite materials indicates the presence of ring-opened monomer, oligomer, and polymer, and, in the case of 1, a…
The electrochemical behavior of conducting polyaniline coatings on various aluminum alloys subjected to immersion in dilute Harrison solution (0.35% ammonium sulfate [(NH4)2SO4], 0.05% sodium chloride [NaCl]) was studied. Electrochemical impedance spectroscopy revealed that the charge-transfer resistance (Rct) of poly…
High resolution transmission electron microscopy is used to image the nanostructure of ultrafine ferroelectric lead titanate particles ranging from 20 to 2000 nm in diameter. The crystal structure, surface morphology, domain–wall structure, as well as surface reconstruction under a 400 KeV electron beam are studied. H…
The intramolecular cyclization in hyperbranching polycondensation reactions of the type AB2/Bf was investigated both theoretically and experimentally. Hyperbranched aliphatic polyesters prepared from 2,2-bis(hydroxymethyl)propionic acid (BisMPA) and 1,1,1-tris(hydroxymethyl)propane (TMP) as B3 core molecule as well as…
Field emission of electrons from multiwall carbon nanotubes (MWCNTs) has been investigated in ultra-high vacuum by field emission microscopy (FEM). MWCNTs whose tips are capped by curved graphite layers give FEM patterns consisting of 6 bright pentagons, each of which has a dark region in its center. Interference frin…
The interplay of topological constraints and the persistence length of ring polymers in their own melt is investigated by means of dynamical Monte Carlo simulations of a three-dimensional lattice model. We ask if the results are consistent with an asymptotically regime where the rings behave like (compact) lattice ani…
Molecular-dynamics simulations show that, in an embedded-atom method nickel crystal, interstitial loops made of $〈110〉$ dumbbells may be absorbed by an edge dislocation in two different ways, either being attached to one of the Shockley partials by means of a dislocation junction or being transformed into a double sup…
We present direct evidence of the phase segregation and magnetic-field-induced structural transition in ${\mathrm{Nd}}_{0.5}{\mathrm{Sr}}_{0.5}{\mathrm{MnO}}_{3}$ as proposed earlier [R. Mahendiran et al., Phys. Rev. Lett. 82, 2191 (1999)] for the collapse of the charge-ordered insulating state. The spontaneous $(H=0)…
Powder synthesis and ceramic processing methods have to be improved to take full advantages of new, improved properties of nanocrystalline ceramics. Sintered nanocrystalline ceramics of pure, undoped zirconia are formed from nanocrystalline powder of optimized quality obtained by the chemical vapor synthesis (CVS) met…
Abstract The Horváth‐Kawazoe (HK) model is a widely used method for determining pore‐size distribution in a microporous material from a single adsorption isotherm. The original model, however, suffers from conceptual flaws. The total interaction energy of the adsorbate is underestimated since the adsorbate‐adsorbate i…
The grain-size effect on phase transition induced by pressure in ZnO nanocrystals has been investigated by in situ high-pressure synchrotron radiation X-ray powder diffraction, optical and electrical resistance measurements. The transition pressure of the B4-to-B1 phase transformation for 12 nm ZnO is found to be 15.1…
Plasma display panel technology has the potential to revolutionize the TV market by providing large and flat displays that can be hung on the wall. The authors introduce the principles of PDP technology (see Figure), and discuss their approaches to the problems related to the luminescent materials that must be overcom…