Materials Literature
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The NH4MgF3 perovskite undergoes a structural and reorientational phase transition at Tc=107. 5±0. 1 K. The librational motion of the NH+ 4 ion below Tc is hindered by a barrier producing an activation energy of Ea/k = 850 K, and correlation time of c=50 fs, as found in N. M. R. measurements. Tunnelling in the ground…
The X-ray contrast material metrizamide is structurally related to 2-deoxyglucose and inhibits brain glucose phosphorylation in vitro. In vivo, the present autoradiographic study with labeled 2-deoxyglucose revealed a global reduction of brain glucose phosphorylation after metrizamide administration in the cisterna ma…
ADVERTISEMENT RETURN TO ISSUEPREVArticleResonance Raman spectra of the carbon-bridged iron porphyrin dimer, (.mu.-carbido)bis[(5,10,15,20-tetraphenylporphinato)iron]Joseph A. Hofmann Jr. and David F. BocianCite this: Inorg. Chem. 1984, 23, 8, 1177–1180Publication Date (Print):April 1, 1984Publication History Published…
In order to install a commercial 275kV gas-insulated transmission line (called GIL by the authors) on a route with many bends and inclines, a temperature rise test and long-term field test were performed to confirm the current capacity and thermo- mechanical and dielectric characteristics. Fault location and leakage g…
If a complete failure of normal and emergency coolant flows occurs in a light water reactor, fission product decay would eventually cause melting of the reactor fuel, leading to contact with water. An energetic fuel/coolant interaction (steam explosion) may result. Experiments were performed at Sandia National Laborat…
Perchloroethylene and toluene are sorbed by dry wool very slowly at room tem perature. Even at the boil several hours of treatment are required to introduce 2% by weight of these solvents into wool. The rate of uptake of perchloroethylene and toluene by conditioned wool is approximately ten times greater, and treatmen…
Abstract The electron paramagnetic resonance of Pr 4+ in the tetragonal crystal field of ZrSiO 4 is measured at 9.9 GHz at temperatures near to 15 K. Hyperfine constants and g ‐values are reported which, unlike most other rare‐earth ions in this material, show only weak anisotropy. The spectra are interpreted in terms…
The technique of optical reflectance ellipsometry has been used to measure room temperature polarizabilities of three ternary chalcohalides: SbSI, SbSeI and BiSI. This method is shown to be very sensitive to small changes of the differential polarizability, defined herein as r = |(α∥-α⊥)/(α∥ + α⊥)|, where α∥ and α⊥ ar…
X-ray and calorimetric investigations of successive phase transitions (PT's) in crystals of CsLiMoO4 type were made. The theoretical model description of these PT's as of order-disorder type ones is suggested and thermodynamical properties of the model are discussed.
The development of energy efficient gas turbine engines with high thrust-to-weight ratios has increased the need for more titanium static and rotating engine components because of the high property-to-density ratio of these alloys. In the last 20 years advances in alloy development and microstructure control have made…
Effect of ambient temperature simulating different weather conditions has been investigated on insulators of different shapes. It has been observed that for a given salinity of contaminating solution, the amount of salt contained in the contaminated-surface layer is strongly temperature dependent. This is attributed t…
The changes in structure and dielectric properties of some phosphates of the family NanM2(XO4)3 with the change of their temperature strongly suggest the existence of new kind of phase transitions: ferroelectric-superionic conductor and antiferroelectric-superionic conductor.
The effects of forming pressure and sintering temperature on shrinkuge, density, and phase composition of α‐ and β‐SiC were determined. Alpha SiC developed the 4H phase at the expense of the 6H phase at >2150°C. The beta form converted to the 6H phuse at >2000°C, with intermediate development of the 15R and 4H p…
An experimental study of water penetration into a hot particle bed has been conducted. The pattern of water penetration was found to be complicated due to the formation of dry pockets and channels. Overall, the water penetrates down the bed as a single column in the central region, while the annular region near the wa…
Sodium depth profiles were determined in water‐leached glass samples with molar composition 20Na 2 O · 10RO · x Al 2 O 3 · (70 ‐ x)SiO 2 (RO = CaO, MgO, and ZnO) using secondary ion mass spectrometry. The leaching of sodium ions decreases with increasing Al 2 O 3 content in all three glass systems. For x = 0 the leach…
Abstract The contribution of jute constituents, namely, water soluble matters, waxes, pectins, lignin, hemicelluloses, and α‐cellulose in the graft copolymerization reaction of jute fabric with some vinyl monomers was investigated. Styrene, methylmethacrylate, and acrylonitrile were used as the monomers and Fe 2+ /H 2…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSelf-exchange rate for the copper(II)/copper(I) couple complexed to TAAB, an N4 macrocycleElizabeth J. Pulliam and David R. McMillinCite this: Inorg. Chem. 1984, 23, 8, 1172–1175Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Published ini…
E ′ 1 (bridging oxygen vacancy) defect densities have been measured in thermal SiO2 films implanted with ions having various energies and masses. From a plot of the defect production per unit volume versus energy deposited into elastic processes per unit volume we observe a linear slope yielding one E1 defect per 2000…
Abstract : Hydrogen can react with heterogeneities in the microstructure of ferrous alloys. These interactions create the necessary sub-steps for failure - crack or void initiation. The nature and type of interactions of hydrogen with the microstructure, combined with the concept of a critical hydrogen concentration f…
The system CaxSr8-x[Al12O24](WO4)2 has been studied with the view or elucidating the role of cage cation substitution on the phase transition behaviour. Room temperature Guinier photographs show splitting and extra reflections indicating structural variations from orthorhombic through tetragonal to cubic symmetry. DSC…