Materials Literature
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The valence band width of graphite is determined with high accuracy by imaging the momentum distribution of photoelectrons for various binding energies. Compared to local-density-functional theory, the experimental band width (22.0 eV) is stretched by about 11%. Quasiparticle calculations, which properly describe elec…
Second harmonic generation has been examined for 30ZnO⋅70TeO2 glass with a two-step poling procedure in order to understand the poling temperature dependence of second harmonic intensity. When the poling temperature increases, the second harmonic intensity increases, manifests a maximum at the temperature which we cal…
A nonlinear optical crystal YCa(4)O(BO(3))(3) (YCOB) is phase matchable for third-harmonic generation (THG) of a Nd:YAG laser by type I mixing between 1.064 and 0.532mum . By partial substitution of Gd for Y in YCOB, a solid solution Gd(x)Y(1-x)Ca(4)O(BO(3))(3) gradually changes the phase-matching angles of THG to (th…
In this paper we establish a Morse decomposition of the stationary solutions of the one-dimensional viscous Cahn-Hilliard equation by explicit energy calculations. Strong non-degeneracy of the stationary solutions is proven away from turning points and points of bifurcation from the homogeneous state and the dimension…
Sound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound attenuation at ultrasonic and hypersonic frequencies that is of the same order or even larger than in crystals. The reason is…
The discovery of single–bubble sonoluminescence has led to a renewed interest in the forced radial oscillations of gas bubbles. Many of the more recent studies devoted to this topic have used several simplifications in the modelling, and in particular in accounting for liquid compressibility and thermal processes in t…
Minor addition of Cu to Nd4.5Fe77B18.5 melt-spun alloy is effective on reducing the grain size of the Fe3B/Nd2Fe14B nanocomposite permanent magnet produced via the crystallization route from the amorphous phase, thereby improving hard magnetic properties. Three-dimensional atom probe and transmission electron microsco…
Recent observations of the collapse of single bubbles or clouds of cavities trapped within stationary acoustic fields have shown the production of light and these phenomena have been dubbed single– or multiple–bubble sonoluminescence. The experimental observation of the variations in the bubble radius with time, with…
Optical absorption and luminescence experiments were used to study the photoconversion of neutral oxygen vacancies (F centers) in MgO single crystals thermochemically reduced at elevated temperatures. In crystals with an undetectable concentration of hydride ions and a moderate concentration of F centers $(\ensuremath…
The electronic properties of carbon nanotubes are investigated in the presence of a magnetic field perpendicular to the nanotube axis and disorder introduced through site-energy randomness. The magnetic field is shown to induce a metal-insulator transition for the metallic $(9,0),(12,0)\dots{}$ nanotubes in the absenc…
We have used quantitative X-ray microscopy in combination with Scanning Force Microscopy to monitor the phase separation of spun cast thin films of polystyrene and poly(methyl methacrylate) blends upon annealing. Both techniques complement and enhance each other in elucidating the complicated structures that develop a…
The $(1\ifmmode\times\else\texttimes\fi{}1)$ to $(2\ifmmode\times\else\texttimes\fi{}1)$ surface phase transition of the hydrogen-covered diamond (111) surface is investigated by core level spectroscopy, low-energy electron diffraction, and measurements of the electron affinity. The latter method is shown to be a reli…
Over the last few years, a large number of chemists and engineers working in synthesis and processing have developed an interest in sonochemistry: the applications of power ultrasound in chemistry. Scientific papers reporting the remarkable results obtained using sonochemistry are plentiful and yet the subject still d…
Combining spectroscopic methods probing both occupied as well as unoccupied electronic states, the surface electronic structure of ex situ prepared boron-nitride films is analyzed and compared to experimental and theoretical bulk-electronic properties taken from the literature. X-ray photoelectron spectroscopy is appl…
The degree of crystallinity of a set of monoclinic (alpha) isotactic poly(propylenes), prepared by a metallocene-type catalyst, were determined at room temperature. Three different methods were used: density, enthalpy of fusion, and wide-angle X-ray scattering, and the results compared. The relation between the heat o…
The catalytic oxidation of CO on O-precovered Pt(111) surfaces has been modeled via ab initio local-density-functional calculations. It is shown that at coverages of ${\ensuremath{\Theta}}_{\mathrm{O}}\ensuremath{\sim}0.5$ the coadsorption of CO stabilizes the chemisorbed molecular precursor of ${\mathrm{O}}_{2}$ over…
Dielectric ac measurements in the frequency range of ∼1 mHz–1 MHz were performed on β-Ta2O5 samples made by chemical vapor deposition. A method of estimating the dielectric constant and the dc conductivity from the dielectric response was developed. The high-frequency dielectric constant was found to be 25.84 with no…
The perovskite ${\mathrm{SeCuO}}_{3}$ is unusual for possessing (i) a very small $A$-site $({\mathrm{Se}}^{4+})$ radius, (ii) highly distorted Cu-O-Cu bond angles $\left(\ensuremath{\alpha}\right)$, and (iii) a ferromagnetic (FM) ground state. Negative chemical pressure is applied by replacing Se with Te in solid solu…
Multiwall carbon nanotubes were irradiated by 2.5-MeV electrons with different fluences. Nanotubes appear to be very resistant to radiation, without radiolysis effects. The radiation-induced defects, which were nearly exclusively point defects, were found to significantly modify the electronic properties of the tubes…
Sonoluminescence is investigated experimentally from the perspective of the dynamics of a single inertial cavitation bubble levitated in an acoustic sound field. The discussion includes bubble levitation, the inertial cavitation threshold, the parameter space in which stable singlendash;bubble sonoluminescence is obse…