Materials Literature
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Abstract Physical blowing agents such as n‐pentane and methyl formate and, for comparison, chemical blowing agents such as water were used to prepare structural polyurethane rigid foams of different densities by reaction injection molding. Experimental runs were carried out with formulations based on oligomeric isocya…
The fuel elements for Chinese 10 MW High Temperature Gas-cooled Reactor (HTR-10) are spherical all- ceramic fuel elements (SFE). TRISO (Tri-isotropic) coated fuel particles (CP) are uniformly dispersed in the graphite matrix of the fuel element. All radiological fission products are almost completely retained inside t…
An integrated computational approach to microstructural evolution and electrical transport in ceramic gas sensors has been proposed. First, the particle‐flow model and the continuum‐phase‐field method are used to describe the microstructural development during the sintering of a prototype two‐dimensional film. Then, t…
This paper presents a feasibility study to develop conductive knitted-fabric-reinforced thermoplastic composites for electromagnetic shielding applications. Polypropylene is the matrix phase, and glass fibers are the reinforcement phase of the composite material. Stainless steel wires and staple yarns are incorporated…
The effect of postdeposition annealing to 600 °C in vacuum on the hardness, modulus, film stress, and sp3 content of nonhydrogenated amorphous carbon was studied. The films were deposited using a filtered cathodic arc source and the film properties were varied by controlling the substrate bias. In films with an initia…
Abstract The grafting of polystyrene onto dissolved starch in a twin screw extruder has been studied. This copolymerization was initiated using the thermal initiators benzoyl peroxide and K 2 S 2 O 8 . As end product a mixture containing polystyrene‐grafted starch, homopolymer of polystyrene and starch was obtained. P…
L-Methionine gamma-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) dependent alpha,gamma-elimination of L-methionine. We have determined two crystal structures of MGL from Pseudomonas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures have been refined to…
Modifications produced on a vulcanized styrene –butadiene rubber surface by treatment with sulfuric acid were studied and several experimental variables were considered. The treatment of R1 rubber with sulfuric acid produced a noticeable decrease in contact angle which was mainly ascribed to an increase in surface ene…
Abstract Three thermal probes were constructed in accordance with ASTM D 5334 and calibrated using heat-flow metre data. The temperature-time response of the thermal probes for determining apparent thermal conductivity λ under transient state conditions was logged at 1 s intervals. The instrumentation used reduced the…
Visible Raman spectroscopy excited at 532 nm was used to characterize the carbon bonding in tetrahedral amorphous carbon (ta-C) films. The vibrational modes of the sp3 bonding in ta-C films were revealed directly. An additional Raman band occurring below 1350 cm−1 was observed. It consisted of two features centered on…
The temperature dependence of the dielectric and piezoelectric properties of a 0.72Pb(In 1/2 Nb 1/2 )O 3 -0.28PbTiO 3 binary system single crystal oriented along the [001] axis near a morphotropic phase boundary was investigated in poled and unpoled states. With poling, the permittivity ε r and the dielectric loss tan…
A method is described which uses a scanning electron microscope for the investigation of charge trapping in insulators under electron bombardment. The technique commonly used to deduce the amount of trapped charge and its spatial extent is based on the mirror effect, while in the present approach the electron-beam def…
Amorphous carbon nitride films containing increasing concentrations of nitrogen were deposited by ion beam assisted deposition at a substrate temperature of 150 °C. The relationship between the deposition conditions and the chemical bonding structure was investigated by x-ray photoelectron, ultraviolet photoelectron,…
A quasi-harmonic molecular-mean-field model for analyzing anharmonic temperature evolution of anisotropic displacement parameters is described. Anharmonic effects are taken into account through a Gruneisen-type temperature dependence of effective vibrational frequencies. The method is applied to neutron and X-ray diff…
Large amounts of hydrogen are produced as a result of the anoxic corrosion of iron in the proposed container materials for some geologic repositories. Another hydrogen source, less important than the anoxic corrosion of iron, is the radiolysis of water by the spent fuel radiation. Gas phase formation occurs when the p…
The influence of surface states, defects and adsorbates on the electronic properties of diamond surfaces are discussed. As far as surface states and reconstructions are concerned the principal crystallographic surfaces, (100), (111) and (110), are essentially understood in their adsorbate free form and also when termi…
Two series of homopolyimides based on oxydiphthalic anhydride and bisphenol A bisether-4-diphthalic anhydride were synthesized with 12 kinds of aromatic diamines. Several thermo-processable homopolyimides were the focus of further investigation. The structure–property relationships of these homopolyimides were examine…
Silicon dioxide thin films are deposited on (100) silicon substrates at low pressure (5 mTorr), from O2/tetraethoxysilane (TEOS) helicon plasmas. The reactor is operated at 300 W radio frequency power without any intentional heating or biasing of the substrate. The samples are characterized using infrared spectroscopy…
The smectic-A phase boundaries of a hard-spherocylinder fluid are calculated using a density-functional theory based on one proposed earlier by Somoza and Tarazona [Phys. Rev. A 41, 965 (1990)]. Our calculations do not employ the translation-rotation decoupling approximation used in previous density-functional theorie…
A one-bath process to apply both antimicrobial and fluorochemical repellent finishes to nonwoven surgical gown fabrics is investigated in this study. The finishes are applied to two nonwovens: a polypropylene spunbonded/meltblown/spunbonded fabric and a wood pulp/polyester spunlaced fabric. Four different add-on level…