Materials Literature
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The radial distribution function obtained by neutron diffraction on amorphous carbon films is compared to recent theoretical models. The first-neighbor peak is found to be quite broad for an amorphous semiconductor, in qualitative agreement with the predictions of molecular dynamics. However, the detailed shape of the…
It is shown that root lattices and their reciprocals might serve as the right pool for the construction of quasicrystalline structure models. All noncrystallographic symmetries observed so far are covered in minimal embedding with maximal symmetry.
Abstract The grafting and the crosslinking of polybutadiene during the bulk thermal polymerization of high‐impact polystyrene were studied. The kinetic equations for these two reactions were derived by the use of the moments of the distribution functions. This kinetic model indicates that both the density of grafting…
Abstract The permeability of CO 2 through polyurethane was investigated. It is found that the permeability increases with the decrease of hard segment content and the increase of soft segment length; however, no change of activation energy is involved. The permeability increases with the elevation of annealing tempera…
Abstract A method has been developed to cast novel organic/inorganic hybrid films from multicomponent solutions containing titanium alkoxides, poly( n ‐butyl methacrylate), water, and isopropanol of prescribed compositions. The sol–gel reactions and controlled drying procedure yielded materials of mechanical integrity…
Abstract In recent years, tetraethyl orthosilicate (TEOS) has been used as a precursor in preparing inorganic glasses. The technique, known as the sol‐gel process involves a two step poly(hydrolysis‐condensation)reaction sequence. The work presented here is concerned with the utilization of a suitably functionalized o…
Article The Role of Oxygen for the Spinel Interphase Formation at Diffusion-Bonded Ni/Al2O3 Interfaces) / Der Einfluß des Sauerstoffes auf die Spinellreaktionsschichtbildung an diffusionsverschweißten Ni/Al2O3 Grenzflächen was published on October 1, 1990 in the journal International Journal of Materials Research (vol…
Rare-earth doped phosphors are discussed here which exhibit intense fluorescence well above 1000C. This is a rare characteristic for solidstate materials. One immediate application for them is thermometry. For example surface temperatures of rotating components systems in hostile or restricted environments and systems…
It has previously been determined that absorption of infrared radiation in germanium due to free carriers can be controlled to some extent by doping. As a result, the use of germanium in infrared systems can be extended to thermal environments not possible before. This can be accomplished by using lower resistivity ge…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoisomerization of spirobenzopyran in polystyrene filmToshiaki Ito, Mitsuo Hiramatsu, Isuke Hirano, and Hiroyuki OhtaniCite this: Macromolecules 1990, 23, 21, 4528–4532Publication Date (Print):October 1, 1990Publication History Published online1 May 2002Published inissue…
Calcium aluminosilicate glass cements are produced by quenching a liquid from 1600°C to room temperature. After grinding and mixing with water, the glass cements hydrate without activators and develop good mechanical properties. The glass cements based on compositions close to gehlenite develop better mechanical prope…
The use of lyotropic liquid crystal polymers such as Kevlar and Twaron in high tech engineering applications has been common for many years. These materials possess excellent temperature resistance and very good mechanical properties. These two materials are polyaramids, but the newer polybenzazoles are also of a liqu…
Ca3(PO4)2, an essential constituent of bones and teeth, was doped with CeO2 and X irradiated to study its thermoluminescence (TL) and thermally exoelectron emission (TSEE). The intensity of the TL response against irradiation dose was increased remarkably by the addition of Ce ions, the TL peaks being found at (1) 90-…
Samples of apple fiber, corn fiber, oat bran, and soy fiber were heat processed in the autoclave and by microwave heat to determine the processing effect on the physical structure of the fiber. Scanning electron microscopy was used to evaluate these processing effects. Results showed the two processing methods yielded…
A method of significantly improving the tensile strength of PVC and PS re inforced with cellulosic fibers has been developed This method relies on the generation of free radicals to create chemical bonding between the coupling agent and the fibers Also a method of detecting the degree of attachment between silane and…
Abstract Soil samples collected from 33 outcrops of weathered plutonic, hypabyssal, and volcanic rocks scattered along a 1400 km traverse from the West Antarctic coastline to the Polar Plateau were analysed for clay mineral content. Clay minerals present (in approximate order of abundance) are “mica”, chlorite, illite…
Corrosion behavior of mild steel in various hydroxy acid solutions of glycolic, lactic, malic, tartaric, and citric acids was investigated by corrosion tests, electrochemical measurements, solution analysis, and new methods of surface analyses. The corrosion rates of mild steel decreased in the order of malic ( ca. 30…
Diamond particles have been embedded in hot‐pressed zinc sulfide (ZnS) ceramic to improve various mechanical properties while preserving special optical properties. Roomtemperature mechanical tests on small specimens have shown that adding 10 wt% diamond to ZnS has no effect on the yield stress, but increases the tens…
Abstract Poly(vinyl chloride) was mixed with various poly(methacrylate)s and polycarbonates by combined precipitation from common solutions. The thermal stability of the samples was measured at 180°C under nitrogen, the HCl evolved was detected by conductometry. UV‐Vis‐spectra of degraded samples were measured to inve…
Abstract Spherical halloysite aggregates have been identified for the first time in mineral matter isolated from bituminous coals. The spherules, found in Permian coals of the Sydney basin, New South Wales, range from 0.4 to 0.6 µ m in diameter and have a delicate ring-like structure that helps to confirm the halloysi…