Materials Literature
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Implementation of the Judd–Ofelt theory of induced electric dipole transitions is considered for rare-earth ions in LaF3. Parameters in the theory are derived a priori. Calculations of the multiplet-to-multiplet line strengths, lifetimes, branching ratios, and line-to-line squared matrix elements are performed between…
The nonlinear Thomas-Fermi equations which describe the screening of intercalant layers in graphite intercalation compounds are solved analytically in the approximation that the graphite $c$-axis band dispersion is neglected. The total energy of the system of charged intercalant layers and the self-consistent charge d…
Highly transparent (over 90% transmission in the visible range) and highly conductive (resistivity ≃2×10−4 Ω cm) indium oxide (undoped) films have been produced by thermal evaporation from an In+In2O3 source in a vacuum chamber containing low pressures of O2. These properties are comparable or superior to the best tin…
The electrical conductivity of a charged layer of graphite is calculated from first principles within a tight-binding framework. The Fermi surface consists of circles around the $P$ points in the Brillouin zone. In the neighborhood of these points we obtain analytical expressions for the electron-phonon coupling ${g}_…
The results of an experimental study of electrical conductivity and thermopower in doped polyacetylene are reported. Included are measurements on both as-grown and partially oriented films doped with iodine and AsF5; [CH(AsF5)y]xand [CH(I3)y]x, where y covers the full doping range. The data indicate three important co…
Window-leaved plants are succulent plants which possess areas of clear epidermis on their leaves. The underlying water storage tissue is transparent to allow light penetration to the internal chlorenchyma. The most highly evolved window-leaved plants with the most transparent tissue grow completely underground in dese…
A thermochemical ablation model for tantalum carbide loaded carbon-carbons is developed assuming phase equilibrium at the ablating surface with the simplified form of the surface energy balance employing the transfer coefficient approximation for unity Lewis number. The model also utilizes the fail temperature concept…
Utilising a crossed-electron-beam-metal-atom-beam scattering technique differential excitation cross sections at 10, 20, 40 and 54.4 eV incident energies and at scattering angles ranging from 10 to 120 degrees have been measured for the following transitions: (i) elastic scattering, and (ii) excitation from ground sta…
In surface studies, the mirror electron microscope (MEM) can give a picture of electrical and geometrical roughness and simultaneously a continuous measurement of local work-function changes Delta phi ; however, no critical study has been done on the accuracy of such a measurement. Using the MEM, the authors developed…
A detailed low-energy electron diffraction analysis of a clean Fe(110) surface is described. The experimental data base consists of intensity-versus-energy curves (spectra) at 5 directions of incidence with a total of 34 spectra at energies up to 210 eV. A statistical analysis carried out with the reliability factor (…
Infrared reflectivity measurements are performed with a scanning interferometer on a single crystal over a wide range of temperature (300-1350K) especially in the cubic paraelectric phase of barium titanate (T c =395K). The temperature dependence of TO and LO frequencies, dampings and TO oscillator strengths is report…
It is shown that the mixing of vibration-rotation states by nuclear hyperfine interactions causes crossover resonances to appear in infrared saturation spectra. Examples are displayed in the ${\ensuremath{\nu}}_{3}$ band of S${\mathrm{F}}_{6}$ and obtain the tensor centrifugal-distortion constant ${t}_{044}$ and the t…
Abstract It was found that the addition reaction between poly(4‐vinylpyridinium chloride) and electrophilic vinyl compounds, such as acrylic acid, acrylamide, methylacrylate, and acrylonitrile. leads to ammonium quaternary polymers with a transformation degree that depends oil the reactivity of vinyl compounds. The st…
Abstract Usually it is assumed that the interactions between the protons within the molecular layers drive the phase transition of the antiferroelectric squaric acid. In the present work it is proposed that besides these interactions also the interlayer interactions play a central role for the phase transition mechani…
One aim of the ever-increasing standardization of test methods for assessing the resistance of rubber to various tyoes of degradation and other potential failure processes is to give a nore reliable laboratory estimate of service performance. If this aim is to succeed, those developing, and using, such tests should be…
Abstract Chelate polymers of Cu(II), Ni(II) and Co(II) with bis‐oxime of 5,5′‐methylene bis(salicylaldehyde) have been prepared. The square‐planar structure of the complexes was determined on the basis of infrared and electronic spectral measurements in conjunction with magnetic susceptibility measurements. The therma…
Mutants containing fusions of the lac gene to the lysC gene were isolated. In these, the expression of beta-galactosidase was regulated by lysine (and arginine), as previously described for aspartokinase III.
A method to treat the pressure-volume relation in alloys on the basis of the virial theorem is proposed, and then the lattice parameter, the bulk modulus and the formation energy of the disordered 4d transition metal alloys are calculated. In this calculation, the s-d hybridization is neglected and the d band is treat…
New measurements of oxygen self-diffusion coefficients in Cu2O have been performed on single crystals under two oxygen partial pressures (4.6 x 10-4 atm and 0.26 atm) in the stability domain. The stable isotope 18O has been used as a tracer. It has been introduced by a thin film method or by annealing under a constant…
Abstract The cathodic protection effect of zinc in zinc pigmented coatings can be clearly recognized above a certain pigment concentration. According to the results obtained during potentiostatic polarization experiments such an effect can be expected above 90% Zn. This effect will still be present after 30 days in so…