Materials Literature
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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…
A microscopic theory is developed for the bulk and surface elastic constants of biaxial nematic liquid crystals. Our expressions depend on generalized orientational order parameters and on the direct pair correlation function.
Abstract A new double lithium rubidium sulphate, Li 3 Rb(SO 4 ) 2 · H 2 O, was found. Single crystals were obtained by drowning out in a tetramethoxysilane gel medium. The compound crystallises in the space group P 1 with parameters a = 5.1356(4) Å, b = 4.9853(4) Å, and c = 8.2712(9) Å, α = 90.032(7)°, β = 105.729(6)°…
Abstract Heating and cooling were found to affect the structure of carbon fiber polyphenylenesulfide‐matrix composites, as shown by their effects on the DC electrical resistance of the composite in the fiber direction. Matrix flow during first heating above T g and thermal stress buildup during cooling in any thermal…
Abstract Ionic motion and local structure of phenethylammonium ion (C 6 H 5 CH 2 CH 2 NH 3+ ) in a series of phenethylammonium lead(II) halides, [C 6 H 6 CH 2 CH 2 NH 3 ] 2 PbX 4 (X = Cl, Br, I) were studied by means of 13 C cross polarization/magic angle sample spinning (CP/MAS) NMR technique. Among the three salts,…
The transverse crack in thick plate welding is discussed with respect to deposited metal. In recent years, many of the new steel developments such as thermo-mechanical controlled process (TMCP) have been intended to improve weldability. When TMCP steel is used to achieve high strength with lean composition, the weld m…
Photoluminescence (PL) measurements on silicon samples implanted with radioactive Hg isotopes which decay fully or partly through the series Au/Pt/Ir are reported. Results obtained with 193Au isotopes (half-life 17 h) confirm earlier work concerning the involvement of Au in the 735 meV centre first observed in Fe-diff…
Abstract : A constitutive model for ceramics by Johnson and Holmquist has been incorporated and validated in the finite element computer program LS-DYNA2D. Using experimental data acquired at DREV, parameters for high density ceramics (around 98% theoretical maximum density) have been established. The effect of varyin…