Materials Literature
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A cylindrical Al 2 O 3 ‐Ni joint bonded with a 4.0 mm thick composite interlayer of 40 vol% Al 2 O 3 ‐60 vol% Ni was fabricated by powder processing, and the residual strains in the specimen were studied experimentally using neutron diffraction, X‐ray diffraction, and optical fluorescence spectroscopy. Experimental me…
Because the index of refraction is temperature dependent, a temperature gradient across a window causes image blur and bore sight error. Prior to this paper, there have been no direct temperature-dependent measurements reported on the mid-infrared refractive index for sapphire, a popular infrared window material of hi…
The electromechanical coupling coefficient, the piezoelectric constant, the elastic compliance constant and the mechanical quality factor for a poly-L-lactic acid (PLLA) plate elongated to 4 times the original length were determined by a self-resonant method. k 14 =0.064, d 14 =9.82×10 -12 C/N, s 44 E =9.28×10 -10 m 2…
High energy density magnets >400 kJ/m3 are increasingly used in many applications. Conventional casting techniques for sintered magnets reveal the formation of a high quantity of α-Fe and large Nd-rich regions. New techniques, like strip casting, produce homogeneous and fine scaled microstructures and are alrea…
Contrary to common belief, neither reciprocity of the bidirectional reflectance distribution function (BRDF) nor the directional form of Kirchhoff's electromagnetic radiation law can be demonstrated on the basis of energy conservation. The BRDF is generally considered reciprocal as an extension of Helmholtz reciprocit…
Gypsum from "Nderhamcha", a region in Mauritania, has been studied through three techniques: thermo-gravimetry, thermo-differential analysis, and X ray diffraction. It has been proved that the dehydration of this material happens in two stages, characterized by the closeness of their temperature. The thermal study as…
A new mechanism is proposed to explain the colossal magnetoresistance and related phenomena. Moving electrons accompanied by Jahn-Teller phonon and spin-wave clouds may form composite polarons in ferromagnetic narrow-band manganites. The ground-state and finite-temperature properties of such composite polarons are stu…
A new microcalorimeter for measuring heats of adsorption on clean single-crystal surfaces is described, and its operational characteristics are presented. The principle is similar to that pioneered by David King’s group: A pulse of gas from a molecular beam adsorbs on an ultrathin single crystal’s surface, causing a m…
The influence of microstructure on the corrosion rate of steels in a carbon dioxide (CO2)-containing aqueous solution was measured experimentally as a function of pH, temperature, and partial pressure of CO2. An attempt was made to quantify and relate the microstructure to the corrosion rate. The effect of alloy micro…
The thermal conductivities of α-Al2O3 and κ-Al2O3 wear-resistant coatings are measured using the 3ω method in the temperature range 80<T<600 K. The coatings are 13 μm thick and deposited by chemical vapor deposition on substrates of Co-cemented WC. The α-Al2O3 coating has a thermal conductivity comparabl…
The effect of O16→O18 isotope exchange on the electric resistivity was studied for (La1−yPry)0.7Ca0.3MnO3 ceramic samples. It was found that at y=0.75, the substitution of O16 by O18 results in the reversible transition from a ferromagnetic metal (FM) to charge ordered (CO) insulator at zero magnetic field. The applie…
Local spin density approximation calculations are used to elucidate electronic and magnetic properties of the Heusler structure ${\mathrm{Fe}}_{2}\mathrm{VA}1$. The compound is found to be a low carrier density semimetal. The Fermi surface has small hole pockets derived from a triply degenerate Fe derived state at $\e…
We use first-principles density-functional total-energy and polarization calculations to calculate the piezoelectric tensor at zero temperature for both cubic and simple-tetragonal ordered supercells of ${\mathrm{Pb}}_{3}{\mathrm{GeTe}}_{4}.$ The largest piezoelectric coefficient for the tetragonal configuration is en…
The structural properties of the (Zn, Mg) (S, Se) solid solutions are determined by a combination of the computational alchemy and the cluster expansion methods with Monte Carlo simulations. We determine the phase diagram of the alloy and show that the homogeneous phase is characterized by a large amount of short-rang…
In this paper we present a computer simulation study of the phase behavior of the Gay-Berne liquid crystal model, concentrating on the effects of varying the molecular elongation $\ensuremath{\kappa}.$ We study a range of length-to-width parameters $3<~\ensuremath{\kappa}<~4,$ using a variety of molecular dynami…
A novel technique for suppression of the multi-photon fluorescence contribution in second-order nonlinear optical hyper-Rayleigh scattering experiments is described. The technique takes advantages of the demodulation and the phase shift in the frequency domain of the time-delayed (multi-photon) fluorescence in the tim…
We invesitgate the electronic correlation effect on the ground-state properties of the double exchange model for manganites by using a semiclassical approach and the slave-boson technique. It is shown that magnetic feild has a similar effect on the canted angle between manganese spins as doping concentration does, and…
Active material actuators, sometimes referred to as "smart" actuators, are gaining widespread use for control actuation. Many of these actuators exhibit hysteresis to some degree between their input and output response. There exists an extensive body of research concerning the modeling of hysteresis for the linearizat…
Computer simulations of a hard sphere system close to the glass transition are presented. From three-time correlations, we obtain information about the single-particle dynamics on all relevant time scales, including the presence of dynamic heterogeneities. A detailed picture of the cage effect in the $\ensuremath{\bet…
This paper focuses on the similarities and differences between metamorphic \ngraphite (formed in situ from organic matter) and fluid-deposited graphite. \nWe discuss the formation of fluid-deposited graphite in terms of the source of \ncarbon, the characteristics of the C-bearing fluids (the C-O-H system),…