Materials Literature
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An alloy containing about 2 at% Mn and 98 at% Bi should solidify at 230°C to give a eutectic consisting of about 3 vol % ferromagnetic MnBi in a matrix of diamagnetic Bi. Directional solidification of this alloy produces a structure of elongated parallel MnBi rods with diameters from 0.1 to 1.5 μm, decreasing with inc…
Abstract High-temperature X-ray diffraction analysis has revealed that Ca2Fe2O5 remains in the original brownmillerite-like form up to ca. 1100 °C, whereas Sr2Fe2O5 changes in crystal structure from brownmillerite to anion-deficient perovskite, without a change in oxygen content, above 700 °C.
Abstract 1. Conventional silica-reinforced NBR vulcanizates are characterized by stiffness at low elongation and low modulus at high elongations. These properties are associated with reticulate structure formation of silica particles, which occurs rapidly when compounds are heated to curing temperatures. 2. An NBR ter…
The anodic oxidation of nickel in solution has been studied employing potentiostatic and galvanostatic techniques. It has been found that although a large amount of charge is consumed during anodic oxidation, only about 5% of this charge is involved in film growth. The thickness of the passive film on nickel in is bet…
Approximate probabilities of electron excitation (shakeup/shakeoff) from various atomic states during nuclear $\mathrm{ns}$ electron capture have been calculated in the sudden approximation, using Hartree-Fock wave functions. Total excitation probabilities are much lower than during inner-shell ionization by photons o…
Cine films of eight species of diatoms were analysed with the aid of computers and the technique is described in detail. Programs were written for graphical presentation of the data obtained from the film to illustrate velocity and acceleration characteristics of movement. Movement is characterized by rapidly fluctuat…
The magnetocaloric effect in polycrystalline Dy was measured between 84 and 280 K in measuring fields from 1 to 7 T. These adiabatic temperature changes reflect structural changes in Dy with applied field and temperature, and include the first magnetocaloric data for a helical antiferromagnet. These measurements were…
The response of an ideally soft magnetic cylinder is calculated by approximating magnetostatic interactions while taking into account the exchange energy of curling patterns with point singularities. Detailed calculations of the magnetic surface charge distribution of paramagnetic materials are used as a guide in para…
The spin wave spectra of three Heusler alloys (X2MnZ) measured by Ishikawa et al have been analysed by means of a model containing the three magnetic interactions which we believe are present in these materials: Coulomb exchange between localized dl and itinerant di electrons, s-dl exchange, and superexchange via the…
Abstract The process of polyethylene terephthalate (PET) formation in the presence of dicarboxylic acids has been studied. Certain amounts of terephthalic acid (TPA) have two‐ to threefold accelerating efficiency in the polycondensation process. To elucidate the causes of the acceleration the main reactions leading to…
Corrosion products initially formed in a wet H2S environment with varying oxygen concentrations were consistently found to be FeS (Mackinawite). After exposure to the atmosphere, these products oxidized to FeO(OH) (Lepidocrocite) and elemental sulfur. Upon further exposure, the FeO(OH) transformed to Fe3O4 (magnetite)…
Abstract The mechanical degradation of pulp cellulose fiber was studied at ambient temperature and at 77°K. ESR findings reveal that mechanical degradation occurs via free‐radical routes. Three types of mechanoradicals contributing singlet, doublet, and triplet ESR signals are identified. The singlet signals are deriv…
A new method for separation and quantitative determination of arbutin, methylarbutin, hydroquinone and hydroquinonemonomethylether in Arctostaphylos alpina, Arctostaphylos Uva-ursi, Bergenia crassifolia, Calluna vulgaris, and Vaccinium Vitis-idaea with HPLC was elaborated. A reversed–phase system with a μ– Bondapak C…
The crevice corrosion of iron in neutral solutions is promoted by chloride ions and inhibited by chromate. For any given concentration of chloride in the range investigated , the crevice corrosion of iron can be inhibited by using a sufficient amount of chromate, with the concentration of chromate required decreasing…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of molecular oxygen with copper(I). Structural characterization of dimeric .mu.-carbonato and tetrameric .mu.-hydroxo complexes resulting from the autoxidation of a copper(I) carbonyl complexRobert R. Gagne, Robert S. Gall, George C. Lisensky, Richard E. Marsh, and…
The hyperfine fields and Curie temperatures of the Heusler alloys (X2MnZ) are analyzed and show that: (1) The s-conduction electron polarization (sCEP) is essentially independent of the X or Z element. It is also independent of the difference in the number of valence electrons between a Cd impurity, at a Z site and th…
Magnetostriction λs has been measured at room temperature and 80 K in Fe100−xBx (14?x?23 at.%) glasses using metal foil strain gauges. Several compositions were also studied as a function of temperature from 80 K to T ? TC. The single-ion uniaxial temperature dependence confirmed previously for Fe80B20 glass is also o…
The effect of a sinusoidal axisymmetric shape imperfection on the plastic buckling of a long cylindrical shell under axial compression is studied. The load at which nonaxisymmetric bifurcation from the axisymmetric state occurs is determined as a function of the imperfection amplitude for relatively thin shells. Imper…
Grain-oriented samples of highly magnetostrictive rare earth–iron compounds have been prepared. These samples possess lower inhomogeneous strains than found in the random polycrystalline RFe2 compounds, resulting in much higher values of relative permeability (μr) and magnetomechanical coupling (k33). A partially orie…
This paper reviews the theory of unwinding from yarn packages and discusses the effect of air drag and gravity on the balloon parameters.