Materials Literature
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We have studied the adsorption of cyclohexane and water on molecularly smooth mica using an angle-averaging, refractive-index-matching ellipsometric technique. The isotherms are linear for submonolayer coverages, showing the importance of entropy effects, and give finite thicknesses (\ensuremath{\approxeq}2 nm) at sat…
Abstract Bitumen from thermal recovery processes is produced mainly in the form of water-in-oil emulsions. Generally, it has been believed that these emulsions form al restrictions in and around the wellbore, and/or in the surface sampling ports, but not in the reservoir. Thus, it has been assumed to be appropriate to…
A laser method based upon carbon ion implantation and pulsed laser melting of copper has been used to produce continuous diamond thin film. Carbon ions were implanted with ion energies in the range of 60 to 120 keV, and doses of 1.0 x 10(18) to 2.0 x 10(18) ions cm(-2). The ion-implanted specimens were treated with na…
Leucine-160 of chloramphenicol acetyltransferase (CAT) has been replaced by site-directed mutagenesis to investigate enzyme-ligand interactions at the 1-hydroxyl substituent of the substrate chloramphenicol. The consequences of the substitution of Leu-160 by glutamine and by phenylalanine were deduced from the steady-…
Successive tensile deformations at different temperatures of high-purity α-iron monocrystals, combined with stress-relaxation tests, reveal that in stress/temperature regime III, i.e. below ≈︁ 120 K, an Arrhenius equation with practically constant pre-exponential factor is valid for the temperature and strain-rate dep…
The microstructures of Nd-Fe-B magnet were examined by scanning electron microscopy (SEM) with wavelength dispersive x-ray spectrometer (WDS) specially equipped lead stearate crystal for lighter elements detection. Investigations were performed on the samples of (Nd0.9Dy0.1)15FebalB8 magnets with various oxygen and ca…
Two microscopic models have been proposed to explain the large intrinsic linewidth of barium ferrite. The first is a two-magnon scattering process due to an intrinsic disorder associated with the unique trigonal bipyramidal site in the crystal. [E. Tsantes and L. M. Silber, J. Appl. Phys. 63, 3350 (1988)]. The second…
Two methods were used to prepare NdFeB alloy particles for sintered magnets: the reduction-diffusion (R/D) method and the melting and casting (M/C) method. In both materials, the Nd-rich phase appears along grain boundaries, but the grain size of the R/D alloy is much smaller than that of the M/C alloy. The shape of t…
Wigner condensation is found to have lowest energy on the perovskite lattice structure. It is suggested that this may be of relevance for studies of high-temperature superconductivity.
Crystal structure parameter of Cr1−xMxAs (M=Ti, Fe, Co, and Ni; x≤0.1) have been precisely determined as a function of temperature from 77 to 320 K. Discontinuous changes of lattice parameters have been observed at a special temperature. By this temperature the Néel temperatures TN of Cr1−xMxAs have been determined be…
Extended x-ray-absorption fine-structure spectroscopy (EXAFS) has been used to determine the position of Zr within the unit cell of Sm2Co17. Induction-melted Sm2Co17:Zr ternary alloys, aged at 1180 °C, then quenched, consisted of intimately mixed H2:17 and R2:17 having Zr in solid solution as well some regions of R2:1…
Dynamic vector Preisach models of hysteresis are developed, and the identification problem for these models is posed. It is shown that some experimentally measured relaxation times can be used for the solution of the identification problem for the dynamic vector Preisach models. Moreover, it is shown that the identifi…
The effect of an additional amount of CaCl2 and the amount of NdCl3 to replace Nd2O3 on the characteristics of the washed Nd-Fe-B powder alloys, and the role of chlorides on the disintegration process have been investigated. CaCl2, CaO, and unreacted Ca surrounded Nd2Fe14B grains uniformly as the chloride amount excee…
The thermal conductivity of 17 alkali halides with the NaCl structure has been calculated. The deformation-dipole model has been used to calculate realistic phonon dispersion relations, which are used to solve the Boltzmann equation with the variational method. Many different trial functions and linear combinations ha…
Pressure effects on spin-flop transition temperature (Tsf) of Mn2−xCoxSb have been measured in order to study the nature of spin-flop phase transitions. The magnetic phase diagrams for Tsf versus concentration and for Tsf versus pressure have been determined. Tsf increases with increasing applied pressure (dTsf/dp=2.9…
The intrinsic coercivities Hc of Nd14DyxFe79−xB7 magnets, prepared by a powder metallurgical method, with an addition of Dy (x=2 at. %), reached 21 kOe. The intrinsic coercivity Hc was kept over 10 kOe when the heating temperature was 150 °C and the temperature coefficient α(Hc) = −0.35%/°C was in a temperature range…
Upon cooling, ${\mathrm{Ag}}_{0.6}$${\mathrm{NbS}}_{2}$ shows a transition near ${\mathit{T}}_{\mathit{c}}$=124 K from an Ag-disordered phase to an incommensurately ordered phase. From single-crystal x-ray-diffraction data, the cell parameters of the basic hexagonal unit cell are determined as a=3.355(1) \AA{} and c=1…
The $^{2}$E(D)\ensuremath{\rightarrow} $^{2}$${\mathit{T}}_{2}$(D) emission of substitutional ${\mathrm{Cu}}^{2+}$ in ZnO has been observed in the 3700--5800-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ spectral range under 50-keV electron-beam excitation at cryogenic temperatures. The excitation mechanisms of this cath…
A photoemission investigation of Fe-Pd and Fe-Pt transition-metal alloys, using \ensuremath{\sim}50--150-eV synchrotron radiation, is presented. We consider in particular the spectral distribution of Fe states when approaching the dilute limit. By means of the Cooper minimum in the 4d and 5d photoionization cross sect…
Amorphous thin films of (1−x)BiFeO3-xPbZrO3 for x=0.1–0.9 have been prepared by the technique of rf sputtering and the effects of sputtering conditions and annealing at high temperatures on magnetic properties of such films have been studied through magnetization measurements. A sintered polycrystalline target was use…