Materials Literature
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Reducing high‐purity BaTiO 3 in hydrogen for 1 h at 1275°C leads to an oxygen deficiency x = 0.0036 in BaTiO 3–x with maintenance of the tetragonal/cubic perovskite‐type structure. Reduction at 1325° C leads to x = 0.0073 and brings about transformation to the hexagonal modification. Up to 1500°C ( x = 0.0233) no furt…
Dislocation velocity on the {1̄21̄2}〈12̄13〉 slip systems of zinc monocrystals was deduced from the rate of growth of slip bands. Near 77°K dislocation velocity is directly proportional to stress, and screw dislocations move more rapidly than edge dislocations. The difference between edge and screw dislocation velocity…
Abstract Chromatographic techniques are described which can be used to isolate and identify the linear and the cyclic oligomers of poly(ethylene terephthalate). Extraction of the oligomers from high molecular weight polymer produces at least eight different cyclic species, some of which are isolated and identified. Th…
The underlying mechanisms of several rate processes in ice are examined through cross comparisons of the processes with each other and with experimental observations. The assumption that the migration of orientational defects (Bjerrum faults) is the common origin of dielectric and elastic relaxation leads to a predict…
Ramen spectra of orthorhombic mercury(II) oxide and hexagonal mercury(II) sulphide are reported here. The former contains lines at 331 and 550 cm-1, and the latter at 250, 284, and 343 cm-1. These spectra, together with previously reported infrared spectra, have been interpreted in terms of factor group analyses of re…
SUMMARY Very‐high‐resolution electron microscopy demonstrates similar phase image ‘particles’ in uncontaminated, unsupported thin sections of epoxy‐embedded biological material and in simple thin carbon films, both of which show better than 5 Å resolution. Under such conditions it is possible to examine biological spe…
The applicability of pyroelectric thermometry to temperature change or temperature rate measurement at low temperatures was studied, with particular emphasis on calorimetry. The pyroelectric coefficients, dc dielectric constants, and volume resistivities of three ferroelectric ceramic materials, Clevite Ceramic B, PZT…
The phase diagrams of the ammonium halides were studied to 40 kbar by means of differential thermal analysis. The present work confirms the recent piston-displacement study of the phase diagram of NH4F. The NH4F II–IV–liquid triple point is probably located at 16.8 kbar, 309°C. The melting curve of NH4F III rises to 5…
Recent work on the definition of synergistic effects has provided the basis for designing more efficient new approaches to flame-retardant cellulose. The synergistic role of nitrogen in enhancing flame-retardant characteristics has been confirmed for cotton and rayon fabrics modified with N-hydroxymethyl-3-(dialkylpho…
Surface recombination efficiencies (γ) on metals have been measured as a function of exposure time in steady Oseen flows which provide a step-function increase, or pulse, in oxygen-atom concentration. Cylindrical, circumferentially coated, thin-film resistance thermometers were used to determine the rate of heat trans…
The concept of splitting of dislocations in generalized by the assumption that generalized intrinsic stacking faults, i.e. faults which are unstable as infinite planar defects, can occur in the dissociation of dislocations. The Burgers vectors of the partials are then not defined on the basis of the geometry of the la…
For the region pd<(pd)min, breakdown characteristics U2 = f(pd) are presented for both the noble and the more important molecular gases He, Ne, A, Kr, Xe, N2, H2, NH3, air, CO2, O2 (and Hg), particularly giving the probability of breakdown on which they are based, so that they can be used for dimensioning the relevant…
A tracer sectioning technique was used to measure cation self‐diffusion coefficients in fully dense polycrystalline Y a O 3 and Er 2 O s under oxidizing conditions. The results are described by the relations image for Y 2 O 3 (1400° to 1670°C), and image for Er 2 O 3 (1400° to 1700°C). The greater activation energy fo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of sodium 12-niobomanganate(IV),Na12MnNb12O38.50H2OCharles M. Flynn Jr. and Galen D. StuckyCite this: Inorg. Chem. 1969, 8, 2, 335–344Publication Date (Print):February 1, 1969Publication History Published online1 May 2002Published inissue 1 February 1969htt…
Dielectric properties of pure, unsintered and pressed barium titanate were investigated. The initial nonlinear variation of dielectric constant and dissipation factor with temperature observed is attributed to the water vapor adsorbed on the surface exposed to the pores. The absence of ferroelectric properties and the…
Abstract Für die Bildung von β‐FeOOH ist die Anwesenheit von Chlorid‐ oder Fluoridionen Voraussetzung. Diese können in Form der entsprechenden Säuren oder auch von Salzen vorliegen. Schon bei An‐ wesenheit kleinster Chloridmengen entsteht dabei β‐FeOOH, z. B. auch unter Lochfraßbedingungen, wobei FeCl 2 ·4H 2 O entste…
Temperature effects on the phosphorescence lifetimes and phosphorescence intensities of naphthalene, phenanthrene, pyrene, biphenyl, and the perdeuterated analogs of these four molecules were measured with the use of poly(methylmethacrylate) (PMM) as a rigid solvent matrix. The phosphorescence lifetimes of these molec…
The velocity field and hence stress field for two-dimensional large-amplitude folding of a viscous layer in a less viscous matrix has been determined theoretically by a series of linear incremental problems. The velocity field for each problem was found numerically using a modification of the finite element method. Th…
A range of 27 marine phytoplankton species, representative of several of the principal classes, has been grown under similar conditions in Erd-Schreiber medium with abundant nutrients. Harvesting was carried out 20 days after inoculation while vigorous growth was proceeding. The component fatty acids of the lipids ext…
SYNOPSIS. Uloborus diversus adjusts its behavior while laying sticky spiral in response to stimuli it receives as it moves. The course of the last loop of sticky spiral determines the path the spider takes. The spiders probably sense the angles the sticky spiral makes with the radius and with the last loop of spiral,…