Materials Literature
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Nanosized montmorillonite clay dispersed in small amounts in polymer results in polymer nanocomposites having superior engineering properties compared to those of the native polymer. These nanoinclusions are created by treating clay with an organic modifier which makes clay organophilic and results in intercalation or…
Polycrystalline $\mathrm{La}{\mathrm{Mn}}_{0.5}{\mathrm{Fe}}_{0.5}{\mathrm{O}}_{3}$ is synthesized by a low-temperature method and the magnetic properties of the resulting powder have been studied after annealing the sample in air at different temperatures in the range $200\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\els…
Well-defined dialkylaluminum alkoxides derived from 2-methoxyethanol [R 2 Al(μ-OCH 2 CH 2 OMe)] 2 [where R = Me ( 1a ) and t Bu ( 1b )] and rac -ethyl lactate [Me 2 Al(μ-OCH(Me)CO 2 Et)] 2 ( 2 ) were used as model complexes mimicking intermediate species in the initiation and propagation steps in the ring-opening poly…
Dispersible Mn3O4, CoO, and CuOx nanocrystals were synthesized via thermolysis of simple, generic molecular precursors (metal formates) in hot surfactant (oleylamine/oleic acid) solutions, which showed two-dimensional ordering on copper grids. The metal valence states in the final products were found to depend upon co…
In this work, the feasibility to develop micelle carriers of griseofulvin based on PLA-PEG copolymers was investigated. With the use of the dialysis method of micelle formation, the micellization behavior of a range of PLA(X)-PEG(5) copolymers was investigated. At copolymer concentrations in the organic solvent 10-20…
The electrical, optical, and electrochemical properties of an optically transparent diamond electrode are reported on and compared with those of a commonly used optically transparent electrode (OTE), indium tin oxide (ITO). The OTE was formed by coating a thin film (ca. 0.5−1 μm) of boron-doped diamond on quartz. The…
The novel spirobifluorene diamine monomer, 2,7-bis-amino-2‘,7‘-di- tert -butyl-9,9‘-spirobifluorene, was obtained. The new organosoluble polyimides were prepared from spirobifluorene diamine containing bulky tert -butyl group and conventional dianhydrides as well as 2,2‘-bis(4‘ ‘- tert -butylphenyl)-4,4‘,5,5‘-biphenyl…
Impurities affect the nucleation, growth, and structure of crystals. Here we report the effect of large, spherical, polymethylmethacrylate impurities on the crystal growth of monodisperse, hard, polymethylmethacrylate colloids in a density- and optically matching apolar solvent mixture. Crystal growth, initiated at th…
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTChemical Synthesis of Highly Conducting Polypyrrole Nanofiber FilmAimei Wu, Harsha Kolla, and Sanjeev K. ManoharView Author Information Alan G. MacDiarmid Center for Innovation, Department of Chemistry, The University of Texas at Dallas…
Optical properties of the Ce:YAG glass-ceramic (GC) phosphor for the white LED were investigated. Concentration dependence of fluorescence intensity of Ce<sup>3+</sup>:5d→4f transition in the GC showed a maximum at 0.5mol%Ce<sub>2</sub>O<sub>3</sub>. Quantum efficiency (QE) of Ce<sup>3+</sup> fluorescence in the…
We have developed a Ce:YAG (Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>) glass-ceramic phosphor for the white LED. The glass-ceramic phosphor was obtained by a heat treatment of a Ce-doped SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub>-Y<sub>2</sub>O<sub>3</sub> mother glass between 1200°C and 1500°C for the prescr…
We formulate the problem of probabilistic predictions of global failure in the simplest possible model based on site percolation and on one of the simplest model of time-dependent rupture, a hierarchical fiber bundle model. We show that conditioning the predictions on the knowledge of the current degree of damage (occ…
We report measurements of 19F nuclear spin-lattice relaxation 1/T1 as a function of temperature and external magnetic field in LiY0.998Ho0.002F4 single crystal, a single-ion magnet exhibiting interesting quantum effects. The 19F 1/T1 is found to depend on the coupling with the diluted rare-earth (RE) moments. Dependin…
Numerical simulations based on electronic structure calculations are finding ever growing applications in many areas of physics. A major limiting factor is however the cubic scaling of the algorithms used. Building on previous work [F. R. Krajewski and M. Parrinello, Phys.Rev. B71, 233105 (2005)] we introduce a novel…
The construction of the multi-focal Veselago lens predicted earlier is proposed on the basis of a uniaxial photonic crystal consisting of cylindrical air holes in silicon that make a triangular lattice in a plane perpendicular to the axis of the crystal. The object and image are in air. The period of the crystal shoul…
Excitation of plasmons in a metal nanoparticle leads to localization of electromagnetic fields within the particle, which is expected to result in strong optical nonlinearities. We study ultrafast nonlinearities in optical scattering from single gold nanorods under resonant excitation at the plasmon frequency, and obs…
Time-resolved magneto-optical Kerr spectroscopy of ferromagnetic InMnAs reveals two distinct {\em demagnetization} processes -- fast ($<1$ ps) and slow ($\sim$100 ps). Both components diminish with increasing temperature and are absent above the Curie temperature. The fast component rapidly grows with pump power and s…
We propose a computationally efficient approach to multiscale simulation of polycrystalline materials, based on the phase field crystal model. The order parameter describing the density profile at the nanoscale is reconstructed from its slowly varying amplitude and phase, which satisfy rotationally covariant equations…
Equilibrium crystal structures for ${\mathrm{La}}_{0.5}{\mathrm{Ca}}_{0.5}\mathrm{Mn}{\mathrm{O}}_{3}$ have been calculated using hybrid Hartree-Fock and density functional methods. Two distinct ground states with either conventional checkerboard charge ordering, in which Mn ions have formal valence 3 or 4, or Zener p…
Mechanical relaxation behaviour of various natural volcanic glasses have been investigated in the temperature range RT-1200K using special low frequency flexure (f~0.63Hz) pendulum experiments. The rheological properties complex Young's modulus M* and internal friction 1/Q have been studied from a pure elastic solid a…