Materials Literature
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Hybrid colloids with new and unusual morphologies (see figure) are formed by precipitation of calcium phosphates in the presence of hydrophobically modified double-hydrophilic block copolymer micelles. The use of interactive polymer templates broadens the toolbox of chemistry required for the construction of complex s…
We have studied the effect of disorder on the radiative properties of semiconductor quantum wires by time-resolved photoluminescence spectroscopy. The dependence of the radiative lifetimes is measured over a temperature range extending from 8 to 150 K. At low temperatures we find that the measured dependence does not…
An ab initio LMTO approach and semi-empirical quantum chemical INDO method have been used for supercell calculations of basic point defects - F-type centers and hole polarons bound to cation vacancy - in partly covalent perovskite KNbO3. We predict the existence of both one-site and two-site (molecular) polarons with…
The effective transport coefficients and figure of merit ZT for anisotropic systems are derived from a macroscopic formalism. The full tensorial structure of the transport coefficients and the effect of the sample boundaries are included. Induced transverse fields develop which can be larger than the applied fields an…
We demonstrate theoretically that the electronic ground state of the potassium-covered Si(111)-B surface is a Mott insulator, explicitly contradicting band theory but in good agreement with recent experiments. We determine the physical structure by standard density-functional methods, and obtain the electronic ground…
The Jahn-Teller effect used semi-theoretically to analyse UV-visible spectra of the diamond like-carbon films on Si substrates. By deconvolution of UV-visible absorption spectra of the typical films, different absorption lines found. For each sample, six lines which were related to $\V^\circ$ by Jahn-Teller effect are…
Nickel and Rhodium (001) surfaces display a similar - as from STM images - clock reconstruction when half a monolayer of C/Ni, N/Ni or O/Rh is adsorbed; no reconstruction is observed instead for O/Ni. Adsorbate atoms sit at the center of the black squares of a chess-board, $c(2\times 2)$, pattern and two different rec…
We investigate collective dissipative properties of vibrated granular materials by means of molecular dynamics simulations. Rates of energy losses indicate three different regimes or "phases"in the amplitude-frequency plane of the external forcing, namely, solid, convective, and gas-like regimes. The behavior of effec…
Ab-initio results for structural and electronic properties of NaCl-type FeN are presented in a framework of plane-wave and ultrasoft pseudopotentials. Competition among different magnetic ordering is examined. We find the ferromagnetic phase stable overall. Stabilization over the unpolarized phase is obtained by split…
We study theoretically the collective orbital excitation named orbital wave in the orbital ordered manganites.The dispersion relation of the orbital wave is affected by the static spin structure through the coupling between spin and orbital degrees of freedom. As a probe to detect the dispersion relation, we propose t…
We present a set of molecular dynamics (MD) simulations of strongly charged, flexible polyelectrolyte chains under poor solvent conditions in a salt free solution. Structural properties of the chains and of the solutions are reported. By varying the polymer density and the electrostatic interaction strength we study t…
Abstract Cast irons primarily are iron alloys that contain more than 2% carbon and from 1 to 3% silicon. This article provides a description of iron-iron carbide-silicon system; and discusses the classification, composition, and characteristics of cast irons, such as gray, ductile, malleable, compacted graphite, and w…
Temperature dependence of the principal refractive indices (n 0 and ne ) of three nematic liquid crystals were measured using an Abbe refractometer with a large refractive index prism. The variation of the refractive index anisotropy in the nematic phase which reflects the variation of the orientational order paramete…
The WLF approach is appropriate for lifetime predictions when polymer ageing is controlled by a viscoelastic process (relaxation, creep). This methodology using time/temperature shift will be illustrated by the creep of SBR/NR. When physico-chemical mechanisms are dominant, the Arrhenius approach is the most widely us…
The X-ray powder diffraction pattern of the room temperature phase of Cd 4 GeSe 6 , a II 4 □ IV VI 6 semiconducting material, has been recorded and evaluated. This material crystallizes in the monoclinic space group Cc [No. 9] with a =12.847(3), b =7.407(2), c =12.854(2) Å, β=109.82(1)°, and Z =4. The powder diffracti…
We report on intensity-dependent photobleaching observed fully along the laser-pulse-propagating path as long as a few mm in bulk oxide glass containing colloidal silver particles. A likely mechanism for the photosensitivity is proposed in terms of two-photon ionization of silver particles in the glass, accompanied wi…
Poly(d,l)-lactide (PDLLA) homopolymer, with an average molecular weight of 20,000 daltons, was produced by the ring-opening polymerization of d,l-lactide in the presence of SnCl(2).2H(2)O as the catalyst. The PDLLA sponges loaded with chloramphenicol were prepared by a solvent evaporation technique. The drug loadings…
Abstract Tsugaruite, Pb 4 As 2 S 7 , is a new Pb-As sulphosalt from the Yunosawa mine, Aomori Prefecture, northern Japan. X-ray studies indicated it to be orthorhombic Pnn 2 or Pnnm , a 15.179(1), b 38.195(1), c 8.0745(1) Å, Z = 16 [Pb 4 As 2 S 7 ] with a subcell with c′ = 1/2 c . The six strongest diffractions in the…
Scanning electron microscope (SEM) images of holes or trenches obtained at high acceleration voltages, such as 200 kV, are analyzed by computer simulation. Secondary electrons generated by forward-scattered primary electrons (SE1s), and those by backward-scattered primary electrons (SE2s) are calculated separately, al…
Three new mixed oxides having the nasicon structure and containing arsenic(V) as tetrahedral ion were prepared and X-ray analyzed. The stoichiometry of the three phases can be expressed by the comprehensive notation MeZr 2 As (3− x ) P x O 12 where Me stands for Na + or K + , x equals to 0 and 1.5 when Me=Na, while x…