Materials Literature
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Pulsed laser deposition (PLD) from a hot pressed manganese doped ZnS target using a KrF laser, has produced a high rate deposition method for growing luminescent thin films. Good stoichiometric quality and typical luminescent crystal structures have been observed with a predominant hexagonal phase and little evidence…
Secondary ion mass spectrometry was used to profile the diffusion of oxygen in polycrystalline β-cristobalite and vitreous SiO2. The tracer concentration profiles of cristobalite are consistent with a model based on two mechanisms: bulk and short-circuit diffusion. The profiles of partially crystallized samples contai…
The dynamics around the liquid-glass transition in ${\mathrm{B}}_{2}$${\mathrm{O}}_{3}$ have been investigated by photon correlation spectroscopy. A two-step relaxation is for the first time observed in a ``strong'' network forming glass. The behavior is similar to the fast \ensuremath{\beta} and slower \ensuremath{\a…
We have used light scattering to study the kinetics of polymerization-induced phase separation in a liquid-crystal--polymer mixture. The evolution of the structure factor is compared with scaling predictions for thermally quenched systems. We have also observed a cascading phenomenon where phase separated domains beco…
Giant and isotropic magnetoresistance as huge as −53% was observed in magnetic manganese oxide La0.72Ca0.25MnOz films with an intrinsic antiferromagnetic spin structure. We ascribe this magnetoresistance to spin-dependent electron scattering due to spin canting of the manganese oxide.
At room temperature a large magnetoresistance, \ensuremath{\Delta}R/R(H=0), of 60% has been observed in thin magnetic films of perovskitelike La-Ba-Mn-O. The films were grown epitaxially on ${\mathrm{SrTiO}}_{3}$ substrates by off-axis laser deposition. In the as-deposited state, the Curie temperature and the saturati…
The observation of inversion walls and nematic schlieren textures with singularity of high strength in polymer samples is reported. The polymers are of the type with two-dimensional mesogenic units and flexible spacers in the main chain and all form a nematic liquid crystal phase above melting.
Infrared technology has been used in industrial heating applications for many decades. As infrared heaters and the control of the heaters has improved wider use and acceptance of this technology has resulted. It is now a commonly used means of heating webs and three dimensional objects in hundreds of manufacturing pro…
Abstract The compatibilization and impact modification of blends of a relatively new engineering plastic polyamide 4.6 (PA 4.6) and a poly(aryl ether sulfone) (PSU) are investigated. PSU‐b‐PA6 block copolymers, which can be easily synthesized by ring opening polymerization of ϵ‐caprolactam in the presence of a commerc…
Wide angle x-ray diffraction studies of silk fibers from various races of silkworms were made to evaluate the crystal size and lattice disortion parameters, since these determine the properties of silk fibers. Also, minimum enthalpy for the formation of these fibers was estimated and compared for the various races. Cr…
The direct synthesis of a number complexes with general composition Cu 4 OCl 6 - n(CH 3 ) 2 NH · mSolv, where n = 4, m = 0-2 and Solv = CH 3 OH, DMSO, is reported. It is shown by X-ray structure investigation, that in Cu 4 OCl 6 .4 (CH 3 ) 2 NH the copper atoms are linked by μ 4 -oxygen and μ 2 -chlorine bridging atom…
ADVERTISEMENT RETURN TO ISSUEPREVArticleSorption and transport of sulfur dioxide in polysulfoneP. H. Pfromm and W. J. KorosCite this: Macromolecules 1993, 26, 22, 6141–6142Publication Date (Print):October 1, 1993Publication History Published online1 May 2002Published inissue 1 October 1993https://pubs.acs.org/doi/10.1…
The low temperature and isothermal dynamic mechanical proper ties for different plasticizers like aromatic oil, paraffinic oil, and di-octyl phthalate (DOP) in epoxidized natural rubber (ENR) vulcanizates were stud ied. 10, 20, and 40 phr of aromatic oil were used for studying the effect of plasti cizer concentration…
<div class="htmlview paragraph">Government clean air regulations have prompted much interest in the automotive industry in alternative fuels for lower emission vehicles. Methanol fuels have become the primary focus of the auto companies in meeting these challenges. Even though the corrosiveness of methanol and c…
The crystal structure of the title compound has been determined (space group C2, a=14.600, b=7.759, c=5.142A, β=93.25°, Z=2) and refined to R=8% for 800 reflections. The structure is characterized by vierer single chains [Si 4 O 12 ] parallel to [010], which link edge-sharing zigzag chains of MnO 6 octahedra running p…
Synthetic melanogenesis, using epinephrine and other melanin precursors, within the matrix of hydrophilic polymers and copolymers of 2-hydroxyethyl methacrylate resulted in hydrogels able to absorb ultraviolet and visible radiation. This significantly enhances their value as materials for extraocular (contact lenses)…
Abstract This paper reports on the theoretical and experimental studies of structure formation and strengthening (stiffening) of flexible‐chain polymers. Two techniques of strengthening relying on the melt extrusion, i.e., orientational crystallization (crystallization initiated by melt extension) and drawing (uniaxia…
Space group Pbca, a=9.398, b=9.139, c=10.535A. The structure was solved by direct methods and refined to R=0.024 using x-ray diffractometer data. The structure is a hydroxyl nesosilicate with a single isolated Si tetrahedron and two M 2+ sites. Ca is accommodated in M1, and both Ca and Mn share M2. OH groups are stron…
The optical response in amorphous (a-)Ga 2 Se 3 semiconductor in the 1.2-5.6-eV photon-energy range at room temperature has been measured by spectroscopic ellipsometry. It is found that the dielectric function ε=ε 1 +iε 2 of a-Ga 2 Se 3 strongly resembles those of amorphous tetrahedrally bonded semiconductors. The opt…
The intermetallic compound Nd2Fe14B undergoes four-step phase transformations in a hydrogen atmosphere, namely, hydrogenation, decomposition, desorption and recombination. This phenomenon was observed in a study of the sintering behavior of an Nd-Fe-B magnet in atmospheric hydrogen gas. The sinter produced consists of…