Materials Literature
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An ac calorimetric method is applied to the direct measurement of thermal diffusivity of single fibers. Theoretical analysis is presented, taking into account the two-dimensional ac thermal wave for cylindrical systems and the effect of time delay at the temperature detecting system. Experimental tests are performed u…
The influence of magnetic ordering on the NiO valence band has been studied by angle resolved photoelectron spectroscopy. Measurements have been performed at temperatures above and below the N\'eel temperature (${\mathit{T}}_{\mathit{N}}$), as well as at room temperature. The results show temperature dependence but no…
Within the local-density approximation we have used the linear muffin-tin orbital method, without geometrical approximations, to calculate the electronic structure of red ${\mathrm{HgI}}_{2}$. Using the self-consistent potential we have calculated the energy bands and from these derived the anisotropic frequency-depen…
Thin layers of amorphous hydrogenated carbon (a-C:H) deposited on (100)Si/${\mathrm{SiO}}_{2}$ substrates were studied using atomic force microscopy, electron spin resonance (ESR), and internal photoemission spectroscopy. Layers with optical band gap in the range 3--0.7 eV were found to be homogeneous with respect to…
The Born effective charge ${\mathrm{Z}}^{\mathrm{*}}$ and dielectric tensor ${\mathrm{\ensuremath{\epsilon}}}_{\mathrm{\ensuremath{\infty}}}$ of ${\mathrm{KNbO}}_{3}$ are found to be very sensitive to the atomic geometry, changing by as much as 27% between the paraelectric cubic and ferroelectric tetragonal and rhombo…
In order to clarify the nature of the neutral Mn acceptor in GaP, we have carried out optical-absorption and electron-paramagnetic-resonance (EPR) experiments using both conventional and thermally detected EPR on semi-insulating GaP:Mn. In thermal equilibrium at low temperatures, all the manganese occurs in the charge…
Recent studies on proteins whose N and C termini are in close proximity have demonstrated that folding of polypeptide chains and assembly of oligomers can be accomplished with circularly permuted chains. As yet no methodical study has been conducted to determine how extensively new termini can be introduced and where…
The large single crystals of stoichiometric and nonstoichiometric Gd monopnictides GdX (X=P, As, Sb, and Bi) are grown by the mineralization method (for X=P and As) and Bridgman method (for X=Sb and Bi). A systematic investigation of the transport properties of GdX single crystals is presented. We report on measuremen…
We prepared nonresonant-type homogeneous glasses containing Bi(2)O(3) by the melting method. The thirdorder optical nonlinear susceptibility chi((3)) was found by third-order harmonic generation measurement to be 9.3 x 10(-12) esu. We attribute the nonlinearity of these glasses to the large molar refraction of glasses…
We present a structural and vibrational analysis of several amorphous (disordered) and ordered isomers of a 55-atom gold cluster. A Gupta n-body potential, with parameters fitted to gold clusters, was used to model the metallic bonding in the ${\mathrm{Au}}_{55}$ cluster. The molecular-dynamics method combined with si…
Insulator-metal transitions and related electronic structures have been investigated for single crystals of perovskite-type cobalt oxides $R\mathrm{Co}{\mathrm{O}}_{3}(R=\mathrm{L}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{N}\mathrm{d},\phantom{\rule{0ex}{0ex}}\mathrm{S}\…
A study of the thermoelectric properties of the skutterudite compound CoSb3 was carried out on single crystals grown by the Bridgman gradient freeze technique. p- and n-type samples were obtained over a wide range of carrier concentration. Undoped As-grown crystals show p-type conductivity while n-type samples were ob…
Conventional continuum damage descriptions of material degeneration suffer from loss of well-posedness beyond a certain level of accumulated damage. As a consequence, numerical solutions are obtained which are unacceptable from a physical point of view. The introduction of higher-order deformation gradients in the con…
We report on low-temperature (77 K) far infrared attenuated total reflection (ATR) spectroscopic measurements on a short period GaAs/AlAs superlattice, and discuss the optics of the modes observed. We assess the significance of the ATR technique for determining superlattice phonon parameters. We model the results usin…
We discuss the possibility of the ``mixed state'' in incommensurate charge density waves with three-dimensional order. The mixed state is created by applying an electric field perpendicular to the chains. This state consists of topological dislocations induced by the external field and is therefore similar to the mixe…
Systematic studies of the influence of local microstructure on electromigration (EM) dynamics in submicron Al (0.5 wt % Cu) interconnects were performed using in situ transmission electron microscopy. This approach has allowed us to observe, in real time, voids forming, growing, migrating, pinning, failing a runner, a…
We have grown amorphous hydrogenated boron carbide thin films on a cathode substrate by rf plasma decomposition of diborane and methane. The chemical composition, infrared absorption, optical absorption, microhardness, and adhesion of these thin films were measured. As a function of increasing diborane concentration i…
PART 1 RADIOGRAPHY and MATHEMATICS: Principles of Radiography. Geometric Radiography. The Inverse Square Law. The Exponential Law. PART 2 GENERAL PHYSICS: Laws of Physics (Classical). Units of Measurement. Experimentation and Statistics. Heat. Electrostatics. Electricity (DC). Magnetism. Electromagnetism. Electromagne…
Tunable room-temperature electroluminescence, photocurrent, and photoluminescence in the near infrared (λ∼1.3 μm) has been observed from Ge/Si/Ge/Si1−xGex quantum-well (QW) diodes grown by molecular-beam epitaxy. The QWs are grown on a p+-doped 〈100〉-Si substrate and consist of two thin Ge wells separated by a thicker…
We calculate numerically the full Floquet-Bloch stability spectrum of cellular array structures in a symmetric model of directional solidification. Our results demonstrate that crystalline anisotropy critically influences the stability of these structures. Without anisotropy, the stability balloon of cells in the plan…