Materials Literature
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We investigated the effect of Co stearate as a new reducing agent, with SiO/sub 2/ and CaO additives, on the magnetic and physical properties of SrFe/sub 2/ W-type hexagonal ferrite. We found that the magnetic properties of SrO/spl middot/8.5Fe/sub 2/O/sub 3/ were considerably improved by adding 0.3 wt% of Co stearate…
Field electron emission properties were investigated for nitrogen-doped nanocrystalline diamond films grown on Si substrates from CH4/Ar/N2 gas mixtures by direct current arc plasma chemical vapor deposition (CVD). Different nitrogen content in the gas mixtures and different deposition temperatures were used for the g…
Previous numerical investigations of model silica have shown evidence favouring liquid–liquid phase separation in the deeply supercooled liquid. This thermodynamic instability is argued to be responsible for the polyamorphic behaviour in the glass. In these previous investigations, a method for discerning local densit…
The microhardness ( H ) of single crystal, orthorhombic mullite was measured on (010) and (001) faces from room temperature up to 1400°C. The microhardness versus temperature curves display sigmoidal shapes. The mean microhardness at room temperature is ∼16 Gpa and it decreases with temperature to H is ∼ 13 GPa at 300…
Abstract In this paper, we advocate the use of the Tunnelling global optimization method for phase stability analysis and for multiphase equilibria calculations. The method had been successfully used for solving a variety of phase-equilibrium problems. The Tunnelling method has two steps. First, a minimum (which may n…
The Saccharomyces cerevisiae Tmt1 gene product is the yeast homologue of the Escherichia coli enzyme that catalyzes the methyl esterification of trans-aconitate, a thermodynamically favored isomer of cis-aconitate and an inhibitor of the citric acid cycle. It has been proposed that methylation may attenuate trans-acon…
Abstract In order to improve the stretchability of linear low density polyethylene (LLDPE) for double bubble tubular film (DBTF), the blending of LLDPEs have been investigated. Three LLDPEs of varying densities were blended, and several films having different densities, molecular-weight distributions and composition d…
Nanodispersed metallic clusters of platinum and palladium were incorporated into NaX zeolite cavities by impregnation with acetone solution of corresponding acetylacetonates, solvent evaporation and acetylacetonate thermal decomposition. The acetylacetonate decomposition was followed by thermogravimetry. Modified zeol…
Crevice corrosion on Type 316L (UNS S31603) stainless steel in alkaline chloride solutions was studied by galvanostatic polarization of an occluded specimen with a polytetrafluoro-ethylene (PTFE) crevice former. It is shown that it is possible for crevice corrosion to propagate in such solutions, even at pH > 1…
Six related polyoxypregnane glycosides were isolated and characterised from Caralluma retrospiciens leaves. The compounds were identified as 12beta-benzoyloxy-8beta,14beta-dihydroxypregn-20-one-3-O-[3-O-methyl-6-deoxy-beta-D-allopyranosyl-(1 --> 4)-beta-D-cymaropyranosyl-(1 --> 4)-]-beta-D-cymaropyranoside], 12beta-be…
Abstract Summary: The effect of metal catalysts in promoting the formation of the comb copolymer between a very low density polyethylene (VLDPE) grafted with diethyl maleate and PET has been studied in this paper following a model study based on low molecular weight molecules resembling the local structure of the reac…
Adsorption behaviors of alkanethiol molecules are investigated on the surface of single-walled carbon nanotubes with vibrational spectrophotometer. Butanethiol (C4H9SH), hexanethiol (C6H13SH), nonanethiol (C9H20SH), and dodecanethiol (C12H25SH) molecules are adsorbed on the nanotube surface, and infrared spectra are m…
Dielectric spectra ɛ′(ν) and ɛ″(ν) of Ca1−x PbxTiO3 ceramic samples (x=0, 0.15, 0.2, 0.4) have been studied in the frequency range ν=7–1000 cm−1 at temperatures from 5 to 300 K using IR Fourier spectroscopy and submillimeter-range techniques. In the low-frequency range, polar phonons were established to undergo temper…
Ferroelectric properties of La 3+ -substituted bismuth titanate (BLT) films were modified by Ti-site substitution using higher-valence ions than the Ti 4+ ion. Thin films of V 5+ -, W 6+ -, Zr 4+ - and nonsubstituted BLT, i.e., (Bi 3.24 La 0.75 )(Ti 2.97 V 0.03 )O 12 (BLTV), (Bi 3.23 La 0.75 )(Ti 2.97 W 0.03 )O 12 (BL…
Electron transport properties of single-walled carbon nanotubes are investigated with TTF and TCNQ molecules, i.e., tetrathiafulvalene and 7,7,8,8-tetracyano-p-quinodimethane. TTF and TCNQ are well known strong charge transfer molecules. From the current–voltage measurement in a vacuum, current decreases and increases…
Abstract The crystal field parameter 10Dq [cm⁻¹] of octahedral chromium obtained as the energy of the 4 A 2g → 4 T 2g band of Cr 3+ in the electronic absorption spectra, EAS, of a series of 13 natural grossular-uvarovite garnets with compositions close to the binary join Ca 3 (Al 1– x Cr x ) 2 Si 3 O 12 , depend on th…
Morphologic characterization of polymers by scanning electron microscopy (SEM) is often made difficult by their sensitivity to electron beam damage. We describe here a specimen preparation method for the imaging of polymer blends by low-voltage SEM (LV-SEM) that improves their stability in the electron beam and hence…
The effects of incorporating yttrium aluminum garnet (YAG) into a porous alumina matrix reinforced with Nextel 610 alumina fibers were investigated. Composites with various amounts of YAG added to the matrix were prepared to determine its effect on retained tensile strengths after heating to 1100° and 1200°C. Strength…
Semiconductor micro and nanofabrication lithography techniques for application in microelectronics as well as in micromechanics and optoelectronics can gain significantly from using a dry resist process, since it enables the deposition of a very uniform lithographically sensitive layer on a potentially very small area…
Abstract Summary: Anisotropy in molecular motions of a glassy smectic CA (SmCA) liquid crystal of a main‐chain BB‐5(3‐Me) polyester was examined by dynamic mechanical analysis (DMA) for fibrous monodomain samples with two distinct orientations of smectic layers perpendicular and parallel to the fiber axis. The α ‐proc…