Materials Literature
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Isothermal annealing of thermally shocked UO 2 bars (O/M= 2.00 ±0.01) at 1600°, 1800°, and 2000°C caused crack healing, which was determined from recovery of room‐temperature fracture strength. The activation energy for crack healing was ∼0.5 of that for volume diffusion, and healing occurred at the same rate as grain…
Abstract Earlier theoretical work on aggregation in imperfect gases and in solutions of protein molecules is reformulated here in such a way as to be applicable to a number of aggregation systems in solution. The theory is most easily developed for an “osmotic” solution. It is exact, in principle, and in particular do…
The actions of low symmetry crystalline electric fields and the spin-orbit coupling in the t2g4 electronic configuration have been considered for the interpretation of magnetic data (susceptibility. Mössbauer effect, etc.). The results of numerical calculations of the various spin Hamiltonian parameters (D.E.ḡ.Ā.efg)…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal and molecular structure of a salt of the (o-benzoquinone diimine)tetracyanoiron(II) ionGary G. Christoph and Virgil L. GoedkenCite this: J. Am. Chem. Soc. 1973, 95, 12, 3869–3875Publication Date (Print):June 1, 1973Publication History Published online1 May 2002Publis…
The phase relationships in the six component system NaAlSi_3O_8- \nCaAl_2Si_2O_8-Na_2CO_3-H_2O were determined between 650° and 950°C and 1 kb pressure \nalong the joins Ab_(80)An_(20)-Na_2CO_3 and Ab_(50)An_(50)-Na_2CO_3, both with 10 percent H_2O \npresent. The phase relationships are complex. Crystallin…
Congenitally athymic (nude) mice have been shown to accept for their lifetime full thickness, normal human skin grafts without immunosuppressive therapy. The biological and medical significance of the long-term maintenance of human tissues in nonhuman subjects is discussed.
Lattice constants, grain size, electrical conductivity, and luminescence were measured for sintered BaTiO 3 ceramics doped with 0 to 1.2 at.% rare‐earth ions. BaTiO 3 doped with low levels of rare‐earth ions contains grains 10 μm in size and has lattice constants nearly equal to those of undoped ceramics. In this case…
The elastic constants, thermal expansion, thermal conductivity, and heat capacity are reported for a new class of laser hosts-the silicate oxyapatites. For Ca2La8(SiO4)6O2 the five independent elastic constants obtained from sound velocity measurements are C11=1.71, C12=0.62, C33=1.71, C44=0.52, and C13=0.39×1012 dyn/…
Diffusion in lattice arrays reducible to cubic symmetry can be simulated by Monte Carlo procedures. Tracer correlation factors can be derived for diffusion mechanisms in such arrays which include simple solids with point defects and non-stoichiometric materials with complex defect structures subject to defect-defect i…
The freeze-etching technique was used to examine the effects of fracturing and etching on the appearance of poly-beta-hydroxybutyrate granules from Bacillus cereus. These granules were examined in extracts isolated by hypochlorite or by sonic treatment, and also in fixed and unfixed intact cells; in the latter case th…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTX-ray photoelectron spectroscopic studies on the electronic structures of porphyrin and phthalocyanine compoundsMary V. Zeller and Robert G. HayesCite this: J. Am. Chem. Soc. 1973, 95, 12, 3855–3860Publication Date (Print):June 1, 1973Publication History Published online1 Ma…
The electron-microscope technique of lattice imaging can in favourable circumstances be used to observe the structure of materials directly. The technique is described, and examples of cases in which a direct correlation between image contrast and structural features has been established are given. Procedures for comp…
The optical absorption edge of undoped, lightly Al-doped, and heavily Al-doped Bi12SiO20 single crystals is found to be exponential and follows Urbach's rule with σ0=0.71 at room temperature. The band edge is at 3.25 eV and is broadened by excitons and perhaps by impurities or defects. At 80 °K, the band edge is found…
Abstract The possibility to calculate magnetic moments in elemental disordered systems (amorphous state, lattice distortions, surfaces) using the inhomogeneous electron‐gas model is considered. Therefore a partial summation of the gradient expansion of the kinetic energy density functional is performed, which allows t…
The purpose of this type of experiment is to elucidate structure of the different compounds gradually prepared starting from reaction mechanisms and chiefly from spectroscopic data given perviously to students.
Abstract Electron paramagnetic resonance has been studied for divalent titanium with 3d 2 configuration substituting for Cd in hexagonal single crystals of cadmium sulphide and cadmium selenide. The parameters of the spin‐Hamiltonian have been determined at T = 27 and 77 K. It is found that the symmetry of the centre…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetic studies of permanganate oxidation reactions. IV. Reaction with bromide ionSamuel A. Lawani and John R. SutterCite this: J. Phys. Chem. 1973, 77, 12, 1547–1551Publication Date (Print):June 1, 1973Publication History Published online1 May 2002Published inissue 1 June 1…
A numerical model is presented which describes the strain level build-up in yarns due to multiple strain wave reflections from yarn crossover intersections in a woven fabric subject to ballistic impact. Crossing yarns present barriers from which strain waves are partially reflected. The maximum yarn strain occurs at t…
The effect of dielectric constant on surface discharge of polymer insulators (polyethylene, polycarbonate, polytetrafluoroethylene, and polyamide) with right cylindrical shape was investigated. The experimental results showed that dc flashover voltage was decreased with increase of dielectric constant in polymers.
Binary Sb 2 O 3 ‐GeO 2 glasses containing 45 mol% Sb 2 O 3 and ternary Sb 2 O 3 ‐B 2 O 3 ‐GeO 2 glasses containing 50 mol% GeO 2 were prepared. Their densities (volumes), refractive indices, and infrared spectra were determined, and their colors and high‐temperature viscosities were estimated visually. Small amounts o…