Materials Literature
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The approximate corona-starting relation for concentric cylinders Ec/δ = A + B/√rδ, long established at lower gas densities, has been checked in air to δ = 35 over the respective ranges of inner and outer cylinder diameters of 0.0178 to 0.635 cm and 4.72 to 15.40 cm (Ec = corona-starting field at surface of inner elec…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemistry of Metal Hydrides. II. Spectroscopic Studies of Fluorovinylplatinum(II) DerivativesH. C. Clark and W. S. TsangCite this: J. Am. Chem. Soc. 1967, 89, 3, 533–539Publication Date (Print):February 1, 1967Publication History Published online1 May 2002Published inissue 1…
The thermal expansions of TiB 2 , ZrB 2 , HfB 2 , NbB 2 , and TaB 2 were measured to temperatures above 1600°C by an X‐ray method. Lattice constants were measured for each compound; each had the AlB 2 ‐type hexagonal structure. The mean linear thermal expansion coefficients were calculated from the data and are compar…
Solid solution formation in the system BaTiO 3 —KnbO 3 was established by X‐ray diffraction and dielectric measurements. Solid solutions with cubic symmetry were observed in the composition range from 4 to 90 mole % KnbO 3 at room temperature. The lattice parameter for the BaTiO 3 solid solutions increased with increa…
The processes leading to a spark breakdown or corona discharge are discussed very briefly. A quantitative breakdown criterion for use in high-voltage design is derived by which spark breakdown or corona starting voltages in nonuniform fields can be calculated. The criterion is applied to the sphere gap, and it is show…
The effects of temperature, strain rate, and purity on the yield and flow stresses of α titanium at low temperatures (T < 0.4 T M ) are examined to ascertain the rate controlling dislocation mechanism. The effect of impurity content on the thermal component of the yield and flow stresses increases with the decrease in…
Magnetic properties in VO 2 have been studied in the temperature range from 100 to 380°K with the Mössbauer effect measurement of Fe 57 doped in VO 2 . Above and below the transition temperature, no internal field is observed. The observation indicates that VO 2 is paramagnetic even below the transition temperature an…
The elastic properties of molybdenum single crystals have been measured using thin-rod resonance techniques as a function of temperature from −198° to over +650°C. Molybdenum behaves in a normal manner over this temperature range. Its elastic stiffness coefficients, with the exception of C12 which increased 3%, decrea…
The nucleation and crystallization of Li 2 O‐Al 2 O 3 ‐SiO 2 glasses containing TiO 2 were investigated using transmission electron microscopy of thin sections produced from bulk samples. Phase separation occurs during cooling from the melt, and on heating, a large number of titanium‐aluminum crystals approximately 50…
The stress–strain behavior of single crystals of tantalum, niobium, and molybdenum has been studied in both tension and compression in the temperature range 4.2–400 °K. The crystals were stressed in both the [Formula: see text] and the [Formula: see text] directions.At high temperatures, the yield stress of all three…
Abstract Antiplasticization is applicable to polymers which contain rigid, polar groups and stiff chains, such as many bisphenol polycarbonates and polyesters, 2,2,4,4‐tetramethyl‐1,3‐cyclobutanediol polycarbonates and polyesters, cellulose triacetate, and a commercial poly(sulfone ether). The stiffness, hardness, and…
Abstract The relationships between spectrum and structure in layer-silicates are reviewed, and applied in the study of structural changes occurring during the heating of montmorillonites up to dehydroxylation, and their subsequent rehydroxylation. Information given by infrared spectroscopy on the binding of water in e…
Fe–Al alloys containing 30 to 50 at. % Al were investigated by Mössbauer spectroscopy. Both ordered alloys, having the CsCl or B2 structure, and alloys severely cold-worked by crushing were studied. At room temperature, all of the ordered alloys exhibit only paramagnetic lines, whereas the crushed alloys exhibit both…
Abstract By the incorporation of certain types of additives in bisphenol A polycarbonate, the modulus and tensile strength of the films are increased and the elongation is decreased. This effect is called antiplasticization, because the opposite results are obtained on plasticization—decreased modulus and tensile stre…
The latent hardening produced by straining copper crystals in single glide was investigated by measuring the flow stress on secondary systems. Specimens oriented for slip on these systems were spark cut from large prestrained crystals and tested in tension. These specimens did not always yield on the most highly stres…
A computer program that determines the stress required to move a dislocation through an array of obstacles distributed at random on a slip plane has been written. This program has been used to measure the critical shear stress of random arrays of (a) obstacles of various equal strengths, (b) obstacles with two differi…
A thorough review is made of the application of the Peierls model to the macroscopic plastic deformation of ionic crystals, metals, alloys, and covalently bonded crystals. The effects of the shape of the Peierls hill, kink–kink energies, and the frequency terms on the stress–temperature and activation volume–stress re…
Phenomenological equations between dislocation velocity, effective shear stress, temperature, and pressure are presented. It is suggested that the term "activation volume" be properly assigned to the pressure dependence of dislocation velocity. Indirect methods of determining velocity–stress relations are reviewed, an…
The form of vacancy clusters in quenched aluminium of 99.99% purity has been investigated using transmission electron microscopy techniques. A new four-layer planar vacancy cluster lying on parallel {111} planes has been observed and its structure has been characterized by observing both the unfaulting behaviour of th…
<div class="htmlview paragraph">Theoretical and experimental investigations were carried out for the purpose of predicting and measuring the performance which results from operation of compression ignition engines when anhydrous ammonia is used rather than diesel fuel. Predictions were that ammonia would give sl…