Materials Literature
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SrTiO3 thin films having perovskite structure were fabricated by sol-gel technique with a post-deposition rapid thermal annealing treatment at 550 °C for 60 s. The films exhibited good structural, dielectric, and insulating properties. The measured dielectric constant and loss factor at 100 kHz were 225 and 0.008, res…
Nuclear transport theory predicts the formation of unstable bubbles and rings in the central collision between equal-mass heavy ions. This phenomenon occurs around a beam energy of E/A\ensuremath{\approxeq}50 MeV/nucleon and is due to the compression of the nuclei in the early stage of the collision. As observable con…
The vibrational properties of ${\mathrm{Si}}_{1/2}$${\mathrm{Ge}}_{1/2}$ alloys are studied using first principles interatomic force constants. The effects of disorder are either simulated using large supercells or treated at the mean-field level by the coherent-potential approximation. The latter approach fails not o…
Positive muons injected into solid ${\mathrm{C}}_{60}$, ${\mathrm{K}}_{4}$${\mathrm{C}}_{60}$, and ${\mathrm{K}}_{6}$${\mathrm{C}}_{60}$ form vacuumlike muonium (${\mathrm{\ensuremath{\mu}}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$) with a (6--12)% probability. Observation of coherent spin precession of muonium es…
The gene encoding component S, the small subunit, of glutamate mutase, an adenosylcobalamin (coenzyme B12)-dependent enzyme from Clostridium tetanomorphum has been cloned and its nucleotide sequence determined. The mutS gene encodes a protein of 137 amino acid residues, with M(r) 14,748. The deduced amino acid sequenc…
Fatigue and retention characteristics of ferroelectric lead zirconate titanate thin films grown with Y-Ba-Cu-O(YBCO) thin-film top and bottom electrodes are found to be far superior to those obtained with conventional Pt top electrodes. The heterostructures reported here have been grown in situ by pulsed laser deposit…
Abstract For the purpose of flame retardation, nylon 6 textile was first hydroxymethylated and then the methylol group containing nylon 6 textile was finished with Pyrovatex CP at 160–170°C. The limiting oxygen index (LOI) value increased from 23.6 for the original textile to 31.4 for the modified one. The mechanism o…
Abstract Fiber melt spinning of poly(ethylene terephthalate) (PET) was studied via modification of threadline dynamics. Several techniques were implemented in the high‐speed spinning process for the judicious control of threadline dynamics. This included a thermal conditioning zone (TCZ) for controlling the threadline…
Abstract Transport properties of antioxidants in polymers have a very important role in their effectiveness. Lifetime of a product is strongly influenced by the physical loss of the stabilizer. The diffusion coefficient ( D ) and solubility ( S ) of Irganox 1010 in low‐density polyethylene (LDPE) were studied at 45 an…
Abstract The influence of counterions on the properties of aqueous dispersions of polyurethane (PU) anionomer have been investigated. The PU anionomers were prepared by polyaddition reaction of 4,4′‐methylenebis(phenylisocyanate) with poly(propylene glycol) (PPG), dimethylolpropionic acid (DMPA), and 1,4‐butanediol, f…
Abstract Porous poly(2‐hydroxyethyl methacrylate) (PHEMA) beads cross‐linked with ethylene glycol dimethacrylate (EGDM) were prepared by the suspension polymerization of the monomers in the presence of cyclohexanol or toluene as the diluents. A 20% aqueous NaCl solution containing MgCl 2 · 6H 2 O, bentonite, and gelat…
Abstract This chapter covers the field of channelling and its effects for electrons traversing thin crystals in the transmission geometry. Channelling effects in the reflection or RHEED geometry, where the beam makes a glancing angle with the crystal surface, are treated in Vol. 2, chapter 3. Backscattered channelling…
Saccharomyces cerevisiae has both cytoplasmic and mitochondrial C1-tetrahydrofolate (THF) synthases. These trifunctional isozymes are central to single-carbon metabolism and are responsible for interconversion of the THF derivatives in the respective compartments. In the present work, we have used 13C NMR to study fol…
An X-ray structure analysis of a crystal of mutant Asp229----Ala of cyclodextrin glycosyltransferase from Bacillus circulans (Ec 2.4.1.19) that had been shortly exposed to beta-cyclodextrin showed density corresponding to a maltose bound at the catalytic center. The crystal structure was refined to an R-factor of 18.7…
The effect of thermal annealing and surface coverage on porous silicon photoluminescence was studied in situ in an ultrahigh vacuum chamber. These investigations correlated simultaneously temperature, surface coverage, and photoluminescence intensity. The surface coverage was monitored using transmission Fourier trans…
Changes in dangling bond densities in porous silicon were measured and results indicate a relatively low dangling bond density (roughly 3×1016 bonds/cm3) in as-prepared samples, which increases by a factor of 6–7 upon quenching of the photoluminescence (PL). The electron spin resonance (ESR) data suggest the presence…
Grafted polymer layers are well known as stabilizing agents in colloidal dispersions. Here we show how these polymer ``brushes'' may also deeply modify wetting phenomena by favoring the formation of stable wetting layers of microscopic size. We discuss in particular the influence of a solvated polymer layer on the wet…
The mode coupling theory for supercooled liquid dynamics finds a beta -relaxation regime on mesoscopic timescales. It is caused by the interplay between nonlinear interactions of density fluctuations and phonon-assisted hopping transport. In this regime all correlation functions and spectra can be expressed in terms o…
Absorption spectra from 0.94--5.58 eV are obtained for gas-phase neutral silicon clusters ${\mathrm{Si}}_{18}$--${\mathrm{Si}}_{41}$ using resonant one- and two-color photodissociation spectroscopy. The spectra of all clusters are essentially identical. Above 3.0 eV, they exhibit six sharp absorption peaks with cross…
We present the first investigation of the growth kinetics of diamond films grown homoepitaxially by hot-filament chemical vapor deposition on (100), (110), and (111) natural diamond substrates. Growth rates on the various faces exhibited different functional dependencies on CH4 flow rate, being linear on (100), slight…