Materials Literature
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We report on the spin-polarized electron injection through an Fe(100)/InAs(100) junction. The circularly polarized electroluminescence of injected electrons from epitaxially grown Fe thin film into InAs(100) in an external magnetic field is measured to investigate the spin injection efficiency. The obtained polarizati…
Mn 2p soft X-ray absorption (XAS) spectroscopy excited with circularly polarized synchrotron radiation has been applied to a new class of material, c(2x2)CuMn/Cu(001) two-dimensional ordered surface alloy. A significant X-ray magnetic circular dichroism (XMCD) signal has been clearly observed at T=25K, indicating the…
Phase diagrams for single bubble sonoluminescence (SBSL) are calculated. The employed model is based on a set of ordinary differential equations and accounts for the bubble hydrodynamics, heat exchange, phase change of water vapor, chemical reactions of the various gaseous species in the bubble (N2, O2, and H2O being…
The expulsion dynamics of the last liquid monolayer of molecules confined between two surfaces has been analyzed by solving the two-dimensional (2D) Navier-Stokes equation for a compressible liquid. We find that the squeeze-out is characterized by the parameter g0 ~ P0/(rho c^2), where P0 is the average perpendicular…
Starch, one of the most inexpensive and most readily available of all natural polymers, can be processed into thermoplastic materials only in the presence of plasticizers and under the action of heat and shear. Poor water resistance and low strength are limiting factors for the use of materials manufactured only from…
We study the binding of molecular oxygen to a graphene sheet and to a (8,0) single walled carbon nanotube, by means of spin-unrestricted density-functional calculations. We find that triplet oxygen retains its spin-polarized state when interacting with graphene or the nanotube. This leads to the formation of a weak bo…
The subwavelength imaging quality of a metamaterial superlens is studied numerically in the wave vector domain. Examples of image compression and magnification are given and resolution limits are discussed. A minimal resolution of λ/6 is obtained using a 36 nm silver film at 364 nm wavelength. Simulation also reveals…
Mechanistic models for ethylene copolymerization with Ziegler–Natta catalysts contain many kinetic rate constants. Precise estimates of key parameters are required if the models are to be used to obtain reliable predictions of polymer properties for a specified catalyst over a range of polymerization conditions. In th…
The difference between oxide and hydrogen passivation of small Si nanocrystals is explored by all-electron, hybrid functional DFT calculations with unrestricted geometry optimization. Oxide passivation lowers the band gap by about 2.4 eV for Si 35 cores and by about 1.5 eV for Si 66 cores. The oxide-passivated nanocry…
Cellulose binding modules (CBMs) potentiate the action of cellulolytic enzymes on insoluble substrates. Numerous studies have established that three aromatic residues on a CBM surface are needed for binding onto cellulose crystals and that tryptophans contribute to higher binding affinity than tyrosines. However, stud…
We have investigated the magnetic properties of Mn-implanted n-type ZnO single crystals that are codoped with Sn. Theory predicts that room-temperature carrier-mediated ferromagnetism should be possible in manganese-doped p-type ZnO, although Mn-doped n-type ZnO should not be ferromagnetic. While previous efforts repo…
Systematic variation of the internal geometry of a dielectric core-metal shell nanoparticle allows the local electromagnetic field at the nanoparticle surface to be precisely controlled. The strength of the field as a function of core and shell dimension is measured by monitoring the surface enhanced Raman scattering…
Transmission electron microscopic observation showed that TiO2 nanotubes synthesized via a simple hydrothermal chemical process formed a crystalline structure with open-ended and multiwall morphologies. Unlike multiwalled carbon nanotubes, the TiO2 nanotube walls were not seamless. During alkali treatment, crystalline…
A fundamentally new single-walled and multiwalled carbon nanotube sidewall functionalization technique has been developed in which solvent is not required and the reaction times are greatly shortened (1 h at 60 degrees C). Exploiting the long linear dimension of the nanotube ropes by macroscopic mechanical deformation…
An extensive theoretical investigation of the nonpolar $(101\ifmmode\bar\else\textasciimacron\fi{}0)$ and $(112\ifmmode\bar\else\textasciimacron\fi{}0)$ surfaces as well as the polar zinc-terminated (0001)-Zn and oxygen-terminated $(0001\ifmmode\bar\else\textasciimacron\fi{})$-O surfaces of ZnO is presented. Particula…
We have performed magnetotransport measurements on La2/3Sr1/3MnO3/SrTiO3/La2/3Sr1/3MnO3 magnetic tunnel junctions. A magnetoresistance ratio of more than 1800% is obtained at 4 K, from which we infer an electrode spin polarization of at least 95%. This result strongly underscores the half-metallic nature of mixed-vale…
Liquid crystalline solutions of poly (p-phenylene benzoxazole) (PBO) in polyphosphoric acid (PPA) were prepared and studied. The typical banded texture and disclination of sheared PBO/PPA solution were observed by polarizing optical microscopy (POM), and the microstructure of the periodic aligned polymer chain that in…
Dust from steel processing is a heterogeneous, multicomponent mixture of metal oxides of zinc, lead, and iron, and several trace elements such as cadmium, nickel, cobalt, and copper. The hydrometallurgical separation and downstream processing of nonferrous metals from dust of electric arc furnaces (EAF) was investigat…
Abstract Syndiotactic polystyrene (sPS) and poly(phenylene oxide) (PPO) blends, miscible in the melt state, were crystallized from the melt and the quenched state at different temperatures. The effect of the crystallization temperature on the phase behavior of the blends and the polymorphic changes in sPS was investig…
At high supercoolings, isotactic polystyrene and polybutene-1 have a rounded crystal shape, suggesting kinetic roughening. Still, the growth rates of these polymer crystals show the supercooling dependence derived for nucleation controlled growth. On the other hand, isotactic poly-4-methylpentene-1 1,4 trans-polybutad…