Materials Literature
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A novel resonant method based on a tunnel-diode oscillator (TDO) is used to study the dynamic transverse susceptibility in a Fe nanoparticle system. The magnetic system consists of an aggregate of nanometer-size core (Au)-shell (Fe) structure, synthesized by reverse micelle methods. Static and dynamic magnetization me…
The magneto-impedance (MI) of glass-coated Fe-Ni-Cu microwires was investigated for longitudinal radio-frequency (RF) currents up to a frequency of 200 MHz using an RF lock-in amplifier method. The MI, defined as DZ/Z = [Z(H)-Z(H=0.3T)]/Z(H=0.3T), displays a peak structure (negative MI) at zero field for RF currents w…
Colloidal dispersions of rod-shaped gold particles are obtained by electrodeposition of gold in the nanopores of anodized alumina attached to a conductive support followed by dissolution of the alumina and release of the rods from the support. Coagulation is prevented by steric repulsion due to adsorption of poly(viny…
A software package has been developed for simulating and designing multipole systems containing electrostatic round lenses, electrostatic and magnetic quadrupole, hexapole and octopole lenses, and Wien filters. Using our SOFEM and 3D packages, the field functions and their derivatives of these optical elements can be…
We present for the first time a theory for the long-time wave number ( k -) dependent collective and self-diffusion coefficients D L ( k ,ϕ) and D S L ( k ,ϕ), respectively, of neutral colloidal suspensions at high volume fractions ϕ. This theory is based on the Smoluchowski equation with mean-field–like hydrodynamic…
A new technique for measuring the twist elastic constant (K22) using an in-plane electrode structure was investigated. The variation in the temperature dependence of K22 with respect to the molecular structure of fluorinated phenylbicyclohexane (PBC) compounds was investigated. The experimental cell has in-plane elect…
Pentasilver iododiphosphate, Ag 5 IP 2 O 7 , is the compound with the lowest AgI content in the pseudo-binary system AgI-Ag 4 P 2 O 7 . The X-ray single-crystal structure determination establishes that the coordination spheres of all the silver ions contain both oxide and iodide anions. Silver-ion conduction pathways…
New thermoplastic nonsegmented thiopolyurethanes were obtained from the low-melting aliphatic–aromatic thiodiols 4,4′-bis(2-hydroxyethylthiomethyl)benzophenone (BHEB), 4,4′-bis(3-hydroxypropylthiomethyl)benzophenone (BHPB), and 4,4′-bis(6-hydroxyhexylthiomethyl)benzenophenone(BHHB) as well as hexamethylene diisocyanat…
An improved method is described for the computation of integrals involving effective core potentials. The improved method provides better scalability to higher angular momenta as well as improved speed. The new method is also applied to the determination of the minimum energy structures of Si8C12, Ge8C12, and Sn8C12,…
A new method is presented for simulating discrete Coulomb interaction effects in electron and ion beam columns. The method is applicable to the latest high-throughput electron and ion beam projection systems currently under development as possible candidates for next generation lithography. Monte Carlo simulation is u…
The transformation of a chemisorbed O layer on the Al(111) surface into Al2O3 under electron impact has been monitored by high-resolution electron energy-loss and x-ray photoelectron spectroscopies. Electron irradiation (100 eV) of chemisorbed O was observed to cause spectroscopic changes in the surface layer indicati…
A significant breakthrough in the nitride chemistry of main group elements has been achieved: Surprisingly Sn(3)N(4), for which there had been no proof of existence until now, as well as the isotypic high-pressure polymorphs gamma-Si(3)N(4) and gamma-Ge(3)N(4) have been synthesized. All three compounds crystallize in…
Yttrium sodium oxalate tetrahydrate, [Y(H 2 O)]Na-(C 2 O 4 ) 2 .3H 2 O, was obtained from hydrothermal synthesis and its structure determined from single-crystal X-ray diffraction data. The structure consists of corrugated layers of ninefold-coordinated Y atoms linked together by oxalate groups. Na atoms and water mol…
High-quality ZnO crystals have been grown by vapor-phase techniques and by the hydrothermal method. Depending on the surface preparation technique, some hydrothermally grown crystals contain strain. These strains result in energy shifts of the free excitons as well as relaxation of the selection rules. The Γ6 unallowe…
Domain structures arising as a result of pulsed electric fields are investigated in Pb(Zn1/3Nb2/3)O3–PbTiO3 (PZN-PT) 〈001〉 single crystals by means of etching and environmental scanning electron microscope. It is shown that randomly orientated dendritic domain patterns were created under a pulsed electric field condit…
A series of crystalline oligomers from α-D-cellobiose octaacetate through α-D-cellohexaose eicosaacetate were prepared by homogeneous acetylation of the corresponding cellooligosaccharides and characterized by cross-polarization and magic angle sample spinning (CPMAS) carbon-13 nuclear magnetic resonance (13C NMR) spe…
Polymerizable styrenic surfactants (surfmers) and nonreactive analogs, have been applied in emulsion copolymerization of acrylic monomers in a seeded semibatch process. Stable core-shell latexes with low levels of coagulum and controlled particle size have been obtained; some of them, with either steric or electroster…
We present molecular dynamics simulations of the flow of macromolecules from a bulk melt into a slit of nanometer dimension with strongly attracting walls. Such flow is central to the formation of polymer-layered silicate nanocomposites by direct melt intercalation. In this process, polymer molecules flow from a melt…
Scanning tunneling microscopy results show that irradiation with electrons of primary energies of 90--2000 eV created single-layer deep vacancies on GaAs(110), Si(100), and Si(111). The removal yield was linear with dose during the initial stages of surface modification, but it increased as the surface damage increase…
Cadmium selenide nanocrystals have been made in a transparent polymer matrix by synthesis at room temperature. Particle size is controlled by reaction time or reagent concentration. Larger nanocrystals (≳3 nm) show near-band-edge photoluminescence. Smaller ones have a broad emission extending across the visible region…