Materials Literature
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Excitation spectra of the 4.44-eV intrinsic luminescence in a single crystal of Ca${\mathrm{F}}_{2}$ at liquid-nitrogen temperature was measured using synchrotron radiation in the x-ray region. The intrinsic luminescence at 4.44 eV is due to self-trapped exciton recombination. The intensity of the emitted uv light was…
Abstract When metals are subjected to stress at temperatures in excess of about one third of their melting temperature, it is found that they deform continuously and that they can sustain the stress for a limited time referred to as the rupture life. Constitutive equations are proposed which describe the macroscopic b…
In-plane resistivity measurements, both parallel and perpendicular to the Mo chain direction have been performed on single crystals of beta -MoTe 2 between approximately 10K and 295K. The data suggest the existence of a first-order phase transition near 250K.
Fourier analysis applied to the recently introduced thermal pulse method yields new and unique relations between the time-dependent pyroelectric response of a thin specimen and the Fourier coefficients of the charge or polarization distribution across its thickness. The new analysis is applied illustratively to therma…
Article Les Systemes Binaires Magnesium-Cuivre et Magnesium-Nickel en particulier Non-Stoechiomttrie des Phases de Laves MgCu2et MgNi2 was published on February 1, 1978 in the journal International Journal of Materials Research (volume 69, issue 2).
Abstract In poly(butylene terephthalate) based compositions, thermal degradation of the polymer matrix during processing has to be minimized to achieve quality products. Experience has shown a temperature‐residence time relationship, indicating that for mixing systems with high product temperatures, the residence time…
The uniaxial magnetic anisotropy induced by magnetic annealing has been studied for Co, Co–Ni alloys with the γ\rightleftarrows ε and for Co–Fe, Fe–Ni alloys with the γ\rightleftarrowsα martensitic phase transition. An anomalously large uniaxial magnetic anisotropy was found in both pure Co and Co–Ni alloys, while a m…
A Mossbauer effect study of 57 Co- and 57 Fe-doped Heusler alloys Co 2 MnX (X=Si, Ge, Sn, Ga), has shown that Fe preferentially replaces Mn in the crystal lattice. Variations in the isomer shifts follow trends observed in the system FeX. There is a substantial difference in the Fe magnetic hyperfine fields at the Co a…
Dispersion characterisitcs of magnetoelastic surface waves in highly magnetostrictive cubic crystals are calculated for different bias fields applied along the direction of propagation. Effects of anisotropy are taken into account. The surface waves are found to be leaky or nonleaky depending on the direction of propa…
The Commensurate-Incommensurate (C-IC) phase transition at finite temperature is considered in mean-field approximation taking account of higher harmonics. The phase diagram is given in the (µ, T)-plane, where µ represents a measure of the deviation from 1/3 filledness. It is shown that at proper values of µ successiv…
Abstract A weakly nonlocal version of the nonlocal continuum theory is used to calculate the interaction energy between a pair of identical defects in a face‐centred cubic lattice when the defect spacing is large. The lattice is assumed to be the same that was considered by Hardy and Bullough, namely, an idealized har…
A dielectric-relaxation model has been proposed by Simmons and Taylor to explain anomalous currents in silicon nitride thin films. In this study, similar currents are observed in certain cadmium borosilicate glasses. The presence of a color center and of composition indepedence of the activation energy for electronic…
The magnetic structure of Fe 5 SiB 2 has been investigated using Mössbauer spectroscopy. In the temperature region 140 K-784 K the compound is found to be a simple ferromagnet with the spins parallel to the c -axis. At lower temperatures the spins are located in or close to the ab -plane and there are indications that…
Abstract Die Rutilform des GeO 2 wird über eine endotherme Reaktion mit Cl 2 als Transportmittel, bei Abscheidungstemperaturen unterhalb 900°C, in großen säulenförmigen Kristallen erhalten. Die Farbe der Kristalle ist je nach Versuchsbedingungen gelb bis bernsteinfarben. Der Vergleich der berechneten und der experimen…
High-temperature spin dynamics in one-dimensional, spin 1/2, Heisenberg systems CuCl 2 ·2NC 5 H 5 and Cu(C 6 H 5 COO) 2 ·3H 2 O is studied by the measurements of proton spin-lattice relaxation rate, T -1 1 . The field dependence of T -1 1 can be fitted by an expression T -1 1 = P H -1/2 + Q , which gives direct eviden…
Lithium, sodium and potassium isobutyrates, isovalerates and isocaproates were submitted to a differential scanning calorimetric investigation in the temperature range between 320 K and the isotropic melt region. The collected phase transition temperatures and heat effects are compared to those of the corresponding li…
<div class="htmlview paragraph">The fuel economy was sharply improved from our 1976 model rotary engine cars mainly through modifications to the engine and improvements in the reactivity of the thermal reactor system.</div> <div class="htmlview paragraph">The progress of our development on these item…
Light and electron microscopy revealed that there are both rods and cones in the retina of the eel Anguilla rostrata. The rods predominate with a rod to cone ratio of 150:1. The spectral sensitivity of the dark-adapted eyecup ERG had a peak at about 520 nm and was well fit by a vitamin A2 nomogram pigment with a lambd…
Die Natur von Sb2O5, die bis in die heutige Zeit umstritten war, konnte jetzt durch Kristallstrukturanalyse geklärt werden. Koordinations- und Verknüpfungsprinzipien stimmen mit denen von B-Nb2O5 überein. Dies ist die erste derartige Beziehung zwischen dem Pentoxid eines Haupt- und eines Neben-gruppenelements.
The authors have measured the lattice thermal conductivity of very pure aluminium in the temperature range between 1.5K and 15K by suppressing the electronic thermal conductivity with a magnetic field in the Corbino geometry. Taking into account a linear term in the magnetoresistance in the extrapolation procedure, it…