Materials Literature
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A 161 Dy Mossbauer study has been performed on the cubic equiatomic compound DyMg. From the value of the hyperfine parameters, the isomer shift in the intermetallic compounds of dysprosium and the magnetic properties of the heavy rare-earth-magnesium system are discussed.
Low-energy-electron diffraction $I\ensuremath{-}V$ spectra obtained from the clean, cooled $\mathrm{W}{001}(\sqrt{2}\ifmmode\times\else\texttimes\fi{}\sqrt{2})R45\ifmmode^\circ\else\textdegree\fi{}$ surface structure at 190 K display $2mm$ point-group symmetry, revealing a preferential orienting of equivalent domains.…
We find that certain cyano Schiff bases and cyanobiphenyls with alkyl or alkoxy end groups exhibiting a bilayer smectic-$A$ phase also exhibit a reentrant nematic phase at high pressure. A tentative model of the bilayer smectic phase held in place via the attractive interaction of the alkyl or alkoxy chains accounts f…
The ability of Saccharomyces cerevisiae NCYC 366 to adsorb polydimethylsiloxane (PDS), dispersed in an aqueous emulsion containing stearate emulsifiers and cellulose-based thickeners, is diminished after treatment with trypsin, KOH and HF; treatment with β-glucanase initially caused an increase in binding which dimini…
A method for calculating the coating stress distribution resulting from the statistical spread of geometrical parameters in irradiated fuel particle batches has been developed by Gulden et al. The existing method utilizing coated particles is extended in two ways: A more realistic treatment of the buffer layer is adop…
Abstract In the temperature range from 6 to 40°C the temperature dependence of pitting corrosion may be expressed by the Arthenius‐equation. The lowering of the breakdown potential in this range shows a linear dependence on the reziprokal value of the absolute temperatur. From the temperature dependence of the breakdo…
The saturation magnetizations and anisotropy constants of alloys in the system NdxY1-xCo5have been determined as a function of temperature from 4.2K to the Curie temperature. Measurements were performed on specimens cut from single crystals grown from the melt. The saturation magnetizations of the alloys do not show t…
The resistivity and thermoelectric power of CuxNi1-x films containing 0, 15, 20, and 25 at.% of Cu have been studied in the temperature range 300–675 K. The effect of postdeposition annealing on the microstructure and the transport properties of the alloy films deposited at 100 and 300 K have been studied in detail. T…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of protoporphyrin XIII and protoporphyrin IIIGraciela Buldain, Luis Diaz, and Benjamin FrydmanCite this: J. Org. Chem. 1977, 42, 18, 2957–2960Publication Date (Print):September 1, 1977Publication History Published online1 May 2002Published inissue 1 September 1977h…
Measurements of the thermal-expansion coefficient ${\ensuremath{\alpha}}_{〈111〉}$ in the 111> pseudocubic direction in single crystals of ${\mathrm{K}}_{2}$Re${\mathrm{Cl}}_{6}$ and over a wide range of temperature are reported. Pronounced anomalies are noted in the vicinity of the purely displacive phase transitio…
Abstract L'étude en RMN du 13 C de neuf azapentalènes a été effectuée. Tous les signaux ont été attribués. Dans un cas on a mis en évidence des couplages entre les atomes de carbone et l'hydrogène porté par l'azote pyrrolique, fait exceptionnel dans le cas des hétérocycles aromatiques polyazotés. On démontre l'utilité…
The odd thermal conductivity behavior of transition metal carbides– K increasing with increasing T –has been interpreted as resulting from the strong scattering of electrons by carbon vacancies and polar optical phonons and from the strong scattering of phonons by vacancies and conduction electrons. These scattering p…
The release of the rare fission gases, krypton and xenon, from a high-temperature reactor pebble-bed core is predominantly determined by the heavy-metal contamination of the matrix material during manufacture. In the case of the Thorium High-Temperature Reactor prototype fuel, particles with failed coatings contribute…
The magnetization and susceptibility of flux-grown Fe${\mathrm{Nb}}_{2}$${\mathrm{O}}_{6}$ single crystals have been measured from 80 K down to 1.4 K. An antiferromagnetic ordering was observed at ${T}_{N}=5.5\ifmmode\pm\else\textpm\fi{}0.5$ K. The antiferromagnetic-paramagnetic phase transition induced by an external…
Electron paramagnetic resonance (EPR) in single crystals of gadolinium metal has been studied near its Curie temperature ${T}_{C} (\ensuremath{\simeq}293 \mathrm{K})$. The EPR linewidth $\ensuremath{\Delta}H$ and the resonance field ${H}_{r}$ are measured as a function of temperature between 280 and 330 K, for $\stack…
Abstract Titanium films, freshly evaporated and exposed to varying amounts of oxygen, are studied by ultraviolet and X‐ray photoelectron spectroscopy (UPS and ESCA), using HeI, HeII and AlKα1,2 radiation. The valence band results are compared with previous experimental results and with reported densities of states. Co…
Summary The crystal structure of killalaite has been approximately determined, using a crystal from the original locality. The ionic constitution is Ca 3+ x (H 1–2 x Si 2 O 7 ) (OH), with x ≈ 0·2 for the crystal studied. Crystal data are: monoclinic pseudo cell with a 6·807, b 15·459, c 6·811 Å, β 97·76°, space group…
Thermal annealing characteristics of the glow peaks from 200 to 650 degrees c in Al2O3 thermoluminescent (TL) phosphor have been studied. All the glow peaks show exponential decay and follow first-order kinetics. The trap depths and frequency factors for the glow peaks have been determined from their isothermal decay…
A new and improved gas distributor was developed for use in coating fuel particles for the high-temperature gas-cooled reactor. The coating gas enters the coating furnace through multiple thin regions of a porous plate. This more uniformly disperses the gas and leads to improved coating properties. High-quality carbon…
The silicon carbide (SiC) layer in Triso-coated high-temperature reactor fuel particles is occasionally attacked during irradiation by fission products generated within the kernel material. Investigations to define the cause of the SiC corrosion included ceramographic, microradiographic, and microanalytical studies on…