Materials Literature
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Abstract The change in ring current of octaethylporphyrin, meso ‐tetraphenylporphyrin and phthalocyanine cobalt(III) complexes with axial amine ligands was studied using a double dipole network model. The porphyrin ring current was found to be highest in octaethylporphyrin but decreased by 5% in meso ‐tetraphenylporph…
Hydrogen absorption-desorption properties of some uranium-rich alloys were studied to develop an advanced material for temporary tritium storage. The characteristics of U-33.3at%Zr were analogous to those of U-69.7at%Zr, while the durability to powdering was reduced according to a decrease of zirconium content. The U-…
A number of facilities have been either constructed or are operating to extract tritium from the heavy water moderator systems of nuclear reactors. However it is expected that most fusion reactor concepts would require the recovery of tritium from light water coolant or blanket systems. This paper highlights the signi…
Over 50 variously substituted 5-alkyl-2-phenylpyrimidines have been synthesized. The effect of the presence of an additional olefinic double bond in the terminal position of the alkoxy chain or of a trans-1,4-disubstituted cyclohexane ring on the liquid crystal transition temperatures of these systems has been studied…
Abstract A study of the transport of the dichloromethane in neat poly(aryl‐ether‐ether‐ketone) (PEEK) samples with thicknesses from 0.08 to 3.0 mm with different morphologies was conducted at 35°C. Both sorption and desorption of the solvent were studied. Thermal annealing was used to vary the sample morphology, and d…
In an aircraft fuel, microbial contamination creates serious corrosion problems. The wing tank bottom and sides are affected by the growth of a biological sludge associated with the condensed water. The behavior of the AA(1) 7075 Al alloy in a culture of the principal contaminant, the fungus Cladosporium resinae, is d…
In this paper we describe the effect of oxygen-reactive ion-beam etching of a polyimide film to enhance its adhesion to an overlying, subsequently deposited copper film. The adhesion strength of the copper to the polyimide could be increased by as much as a factor of 25 as a result of the etching. Near the etching con…
Authigenic smectite dominates the silicate mineralogy of sediments underlying the hot brine pools of the Atlantis II Deep geothermal system in the Red Sea. Chemical compositions for monomineralic smectite fractions separated from three different facies give formulae that possibly distinguish three smectite species, on…
Abstract Exposure of polytetrafluoroethylene (PTFE) to MgKα x‐rays (1253.6 eV) for times as short as 10 min is observed to lead to permanent radiation hardening toward chemical etching. X‐ray‐dosed surfaces are visibly less etched, and the loss of F is over a factor of 2 smaller. For PTFE itself, the x‐ray photoelectr…
Abstract Symmetrically substituted octaalkyl- and octaarylporphyrins are readily prepared by the reduction of 2-ethoxycarbonyl-3,4-diarkyl (or diaryl)pyrroles with LiAlH4 followed by treatment with acetic acid and oxidizing agents.
The postirradiation fracture toughness responses of Types 316 and 304 stainless steel wrought products, cast CF8 stainless steel, and Type 308 stainless steel weld deposit were characterized at 427°C using JR curve techniques. Fast neutron irradiation of these alloys caused an order-of-magnitude reduction in Jc and tw…
Continuing advances in hardware and software have improved both the speed and the range of computations that can be made to simulate high resolution electron microscope (HREM) images from various structures. Use of image display systems and array processors have made the image simulation procedure much more interactiv…
Physical interactions between pyridoxal kinase and aspartate aminotransferase were detected by means of emission anisotropy and affinity chromatography techniques. Binding of aspartate aminotransferase (apoenzymes) to pyridoxal kinase tagged with a fluorescent probe was detected by emission anisotropy measurements at…
The fructose-2,6-bisphosphatase domain of rat liver 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (EC 2.7.105/EC 3.1.3.46) was expressed in Escherichia coli by using an expression system based on bacteriophage T7 RNA polymerase. The protein was efficiently expressed (i) as a fusion protein that starts at the T7…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA New Pentacyclic Triterpene from Calotropis proceraAbdul Qasim Khan, Zaheer Ahmed, Syed Najam-ul-Hussain Kazmi, and Abdul MalikCite this: J. Nat. Prod. 1988, 51, 5, 925–928Publication Date (Print):September 1, 1988Publication History Published online1 July 2004Published ini…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIsomorphous substitution in phyllosilicates as an electronegativity perturbation: its effect on bonding and charge distributionWilliam F. Bleam and Roald HoffmannCite this: Inorg. Chem. 1988, 27, 18, 3180–3186Publication Date (Print):September 1, 1988Publication History Publ…
Total immersion testing of a range of stainless alloys and a mild steel in cultures of sulfate-reducing bacteria (SRB) was conducted. A detailed study of corroded samples under the scanning electron microscope (SEM) indicated that corrosion manifested itself both as pitting and intergranular attack. AISI(1) 304L stain…
The effects of irradiation on the coefficient of thermal expansion (CTE), the density, and the elastic moduli of low‐CTE materials such as amorphous SiO 2 , ultra‐low‐expansion glass, β‐SiC, Astrositall, and Zerodur were surveyed. It was found that the properties of all of these materials were affected by radiation ex…
Five stoichiometric phases of the system that can be represented by the general formula have been identified in high temperature cells. Their formation is dependent on the operating temperature and the state of charge of the cell. The structural characteristics of the five phases, which provide an insight into the rea…
Dicalcium silicates having CaO/SiO 2 molar ratios of 1.8 to 2.2 were sintered at 1450°C for 90 min with or without small quantities of dopants (K 2 O or Al 2 O 3 ) and were air quenched. The microstructures of the fired samples were characterized using electron microscopy (SEM and TEM) and associated microanalytical t…