Materials Literature
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We have investigated the magnetic and chemical properties of very thin Cr films, CrAs, and arsenized Cr grown by molecular beam epitaxy on Ga As (001), using x-ray photoemission spectroscopy and SQUID magnetometry. Distintic preparation procedures have been used with the purpose to undestand the origin of the ferromag…
Cross sectional scanning tunneling microscopy (XSTM) and density functional theory have been used to characterize the structure of GaSb digitally doped with Mn. The Mn dopants are found in both isolated substitutional form as well as in large clusters of zinc-blende MnSb commensurate with the surrounding GaSb matrix.…
The basic mechanism underlying electric field switching produced by a resonant tunnelling diode (RTD) is analysed and the theory compared with experimental results; agreement to within 12% is achieved. The electro-absorption modulator (EAM) device potential of this effect is explored in an optical waveguide configurat…
Heat conduction of a real quasi-one-dimensional material, the finite length carbon nanowire inserted into the single-walled carbon nanotube (SWNT), has been studied by the molecular dynamical method, in which both of the longitudinal as well as transverse motions of the chain atoms in the SWNT have been permitted. It…
We have investigated ab initio the existence of localized states and resonances in abrupt GaAs/Si/GaAs (110)- and (100)-oriented heterostructures incorporating 1 or 2 monolayers (MLs) of Si, as well as in the fully developed Si/GaAs (110) heterojunction. In (100)-oriented structures, we find both valence- and conducti…
A new scheme of first-principles computation for strongly correlated electron systems is proposed. This scheme starts from the local-density approximation (LDA) at high-energy band structure, while the low-energy effective Hamiltonian is constructed by a downfolding procedure using combinations of the constrained LDA…
A simulation study demonstrates that localization can arise as the result of the breakdown of stable quasi-crystal-like atomic configurations. Samples produced at elevated quench rates and via more energetic processes contain a lower fraction of such configurations and exhibit significantly less pronounced localizatio…
We show that there is a fundamental difference between spin Hall current and orbital angular momentum Hall current in Rashba- Dresselhaus spin orbit coupling systems. The orbital angular momentum Hall current has a pure topological contribution which is originated from the existence of magnetic flux in momentum space…
SRR metamaterial is used as a substrate material in a microstrip guided wave structure to determine what the effect is of a material with potentially excessive dispersion or loss or both. A Green's function method readily incorporates the metamaterial permittivity and permeability tensor characteristics. Ab initio cal…
We investigate the transport properties of three-terminal carbon-based nanojunctions within the scattering matrix approach. The stability of such junctions is subordinated to the presence of nonhexagonal arrangements in the molecular network. Such ``defective'' arrangements do influence the resulting quantum transport…
The resistivity model as a function of temperature and ionization energy (doping) is derived with further confinements from spin-disorder scattering in ferromagnetic phase. Magnetization and polaronic effects capture the mechanism of both spin independent and spin-assisted charge transport of ferromagnets, including t…
Platinum dendrimer-encapsulated nanoparticles (DENs) were prepared within fourth-generation, hydroxyl-terminated, poly(amidoamine) dendrimers and immobilized on glassy carbon electrodes using an electrochemical coupling strategy. X-ray photoelectron spectroscopy, electron microscopy, and electrochemical experiments co…
The adsorption of lysozyme (Lz) onto nanoporous carbon molecular sieves with various pore diameters has been studied at different solution pH values. All the adsorption isotherms have successfully been correlated by the Langmuir equation. The amount of adsorbed Lz depends on the solution pH as well as on the specific…
Carbon nanotubes have attracted great interest in multidisciplinary study since their discovery. Herein, radionuclide 243Am(III) sorption to uncapped multiwall carbon nanotubes (MWCNTs) was carried out at 20+/-2 degrees C in 0.01 and 0.1 M NaClO4 solutions. Effects of 243Am(III) solution concentration, ionic strength,…
Hollow microhemisphere and microsphere patterns (see Figure) can be selectively created from the self-assembly of ZnO nanorods and thin nanosheets, respectively. It appears that these distinctive superstructures can evolve from spherical-nanocluster-based aggregates under controlled conditions, presenting the promise…
SIR2004 is the evolution of the SIR2002 program [Burla, Camalli, Carrozzini, Cascarano, Giacovazzo, Polidori & Spagna (2003). J. Appl. Cryst. 36 , 1103]. It is devoted to the solution of crystal structures by direct and Patterson methods. Several new features implemented in SIR2004 make this program efficient: it…
Catalysis by the NADP-dependent non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) from Streptococcus mutans, a member of the aldehyde dehydrogenase (ALDH) family, relies on a local conformational reorganization of the active site. This rearrangement is promoted by the binding of NADP and is strongly…
Based on the theory of coupled transport of electricity and heat in metals, we present a numerical method allowing us to calculate the thermoelectric power (TEP) (Seebeck coefficient) of a two-dimensional metal/metal composite structure. Depending on the arrangement, the surface fraction and the geometry of the two co…
Solid−liquid equilibrium data are reported for l -isoleucine ( l -ILE) + l -valine ( l -VAL) + water at 298 K and ambient pressure, using experimental techniques that involve (a) cooling of an aqueous solution of the two amino acids until crystals are formed, or (b) the addition of one amino acid to an undersaturated…
We have studied the effect of the valence electron concentration, on the bulk modulus and the chemical bonding in Ta2AC and Zr2AC (A=Al, Si, and P) by means of ab initio calculations. Our equilibrium volume and the hexagonal ratio (c∕a) agree well (within 2.7% and 1.2%, respectively) with previously published experime…