Materials Literature
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Total energy, binding energy, recombination rate (of the electron hole pair) for an exciton (X) bound in a parabolic two dimensional quantum dot by a donor impurity located on the z axis at a distance d from the dot plane, are calculated by using the Hartree formalism with a recently developed numerical method (PMM) f…
A novel macroscopically degenerate state called kagome ice, which was recently found in a spin ice compound Dy2Ti2O7 in a magnetic field applied along the [111] direction of the cubic unit cell, is studied by specific heat measurements. The residual entropy of the kagome ice is estimated to be 0.65 J/K mol Dy, which i…
In this work, we have investigated the optical properties of two samples of CdSe quantum dots by using submicro-photoluminescence spectroscopy. The effect of vicinal-surface GaAs substrates on their properties has been also assessed. The thinner sample, grown on a substrate with vicinal surface, includes only dots wit…
We study the creep response of solids to a constant external load in the framework of a novel fiber bundle model introduced. Analytical and numerical calculations showed that increasing the external load on a specimen a transition takes place from a partially failed state of infinite lifetime to a state where global f…
We consider a lattice gas model which in addition to the canonical nearest neighbor pair interatomic interaction accounts for a many-body interaction inside atomic trios. Interactions of this kind arise in the coherent strained epitaxy and were recently used by us to describe some surface phenomena. With the use of th…
The characteristics of acoustic waves propagation in the single crystal lead magnesium niobate-lead titanate(PMN-PT) are theoretically and experimentally investigated. This single crystal has ultrahigh piezoelectric coefficient (d33>2000 pC/N) and electromechanical coupling coefficient( k33>90%). High coupling single…
The efficiency of recently developed RAM (Radar Absorbing Materials) based on conducting polymers in sheet texture has been investigated by X-band (8 to 12 GHz) scattering measurements and, also by determination of their complex dielectric constant by a waveguide method. This paper presents the experimental methodolog…
Une méthode de mesure de la dispersion et de l'amortissement des ondes longitudinales dans une barre élastique ou faiblement viscoélastique est présentée. Elle est fondée sur l'analyse des résonances présentes dans le spectre du signal de la déformation produite par un chargement indéterminé. Appliquée à une barre d'a…
(100)- and/or (001)-preferred-oriented and (111)-preferred-oriented polycrystalline Pb(Zr,Ti)O3 (PZT) films with Zr/(Zr+Ti) ratios of 0.35 and 0.62, corresponding to tetragonal and rhombohedral PZT, respectively, were compared with that of epitaxially grown ones with the same composition and similar orientation from t…
Red, green, and blue light emissions have been obtained at 80 and 300 K by cathodoluminescence (CL) from N-rich turbostratic BN thin films doped with Eu, Tb, and Tm, respectively. The films were grown by rf magnetron sputtering in an atmosphere of Ar and NH3 gas mixture using EuB6, TbB6, and TmB12 targets, respectivel…
Three azobenzene-containing side-chain liquid crystalline polymers (SCLCPs) were grafted onto a styrene−butadiene−styrene (SBS) triblock copolymer to yield photoactive thermoplastic elastomers. The SCLCPs used were a polymethacrylate and two polyacrylates having different glass and phase transition temperatures. We ha…
The extension of the high-power applications of sonic and ultrasonic energy in industrial processing requires the development of efficient and powerful transducers. Years ago some of the authors of the present paper proposed a new concept of ultrasonic transducer for use in fluids (more specifically in gases) based on…
The cluster Ti3O(OPri)8(benzoate)2 is obtained upon reaction of Ti3O(OPri)10 or Ti3O(OPri)9(OMe) with benzoic acid. The remarkable feature of this substitution reaction is that the cluster structure is approximately preserved. Ti3O(OPri)8(benzoate)2 undergoes a dynamic exchange processes of the propoxy groups in solut…
The structure and electronic spectra of merocyanines are intermediate between those of acyclic polyenes and cationic symmetric cyanines of comparable sizes, shifting from one to the other as a result of a solvent polarity change. In this paper we address, both theoretically and experimentally, the question of how the…
Thermodynamic analysis was performed with respect to the effect of surface tension on the expansion characteristics of a one-dimensional nanoscale liquid Ga column inside a carbon nanotube. The analysis showed that the surface tension affects the column inner pressure, and that the smaller the column diameter, the gre…
The presence of oxygen vacancies is considered to be the cause of various phenomena in ferroelectric thin films. In this work, the role of oxygen vacancies is theoretically modeled. Various properties are numerically simulated using the two-dimensional Ising model. In the presence of an oxygen vacancy in a perovskite…
Tensile tests on free-standing, 200-nm-thick Al films were conducted between room temperature and 200 °C. Applied strain rates were in the range 1×10−8–2×10−6/s. At a temperature of 200 °C a saturation of the flow stress was observed. The strain required to achieve steady-state saturation is of the order of 2×10−3, wh…
The valence band dispersions for Bi2Se3 have been determined using angle resolved photoelectron spectroscopy. The experimentally determined band dispersions are compared with theoretical band structure calculations. In general, good agreement between experiment and theory was found. However, energy bands in the Γ-Z di…
This work examines the material characteristics and magnetic properties of hexagonal M-type barium ferrite (BaFe12O19) films deposited by pulsed laser ablation deposition onto (111) magnesium oxide substrates at different oxygen growth pressures. X-ray diffraction data showed the lattice constant of the film grown at…
Experimental results showing that the surface of ferromagnetic materials is spontaneously magnetized by tribological actions such as friction and wear in the absence of external magnetic fields are presented. The magnetization mechanism of the frictional surface and wear particles is discussed based on the results of…