Materials Literature
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We have developed a model to predict the chemical reactivity of carbon nanotubes (CNTs) quantitatively from their initial structures. The parameters, universal for each reaction, of the model can be obtained from a graphene sheet analysis. The chemical reactivity of hydrogenation, hydroxylation, and fluorination were…
ZnO films were prepared on Si(100) substrates using rf magnetron sputtering and the correlations between the growth conditions and the resultant film properties were discussed. The intensity of the visible emission related with intrinsic defects in ZnO film was dramatically suppressed by increasing the O 2 /Ar+O 2 rat…
The electromagnetic (EM) wave absorption properties in the gigahertz region (12–110 GHz) of carbon microcoils (CMCs) with a three-dimensional-helical/spiral chiral structure (1–10 μm coil diameter and 0.1–10 mm coil length) were examined using the open space method. It was found that the target value of reflection los…
The three novel, multi-nickel-substituted heteropolytungstates [Ni(6)As(3)W(24)O(94)(H(2)O)(2)](17)(-) (1), [Ni(3)Na(H(2)O)(2)(AsW(9)O(34))(2)](11)(-) (2), and [Ni(4)Mn(2)P(3)W(24)O(94)(H(2)O)(2)](17)(-) (3) have been synthesized and characterized by IR, elemental analysis, electrochemistry, and magnetic studies. Sing…
Electronic transport through thin and laterally constrained domain walls in ferromagnetic nanojunctions is analyzed theoretically. The description is formulated in the basis of scattering states. The resistance of the domain wall is calculated in the regime of strong electron reflection from the wall. It is shown that…
${\mathrm{K}}_{1\ensuremath{-}x}{\mathrm{Li}}_{x}{\mathrm{TaO}}_{3}$ (KLT) solid solutions exhibit a variety of interesting physical phenomena related to large displacements of Li-ions from ideal perovskite A-site positions. First-principles calculations for KLT supercells were used to investigate these phenomena. Lat…
Excited-state relaxations in molecules are responsible for a redshift of the absorption peak with respect to the emission peak (Franck-Condon shift). The magnitude of this shift in semiconductor quantum dots is still unknown. Here we report first-principle calculations of excited-state relaxations in small (diameter $…
Recent reports have shown enhanced fluorescence for fluorophores in close proximity to chemically deposited silver islands or colloids. To expand the usefulness of metal-enhanced fluorescence we tested fractal silver structures formed on, or near, silver electrodes by passage of electric currents. The emission intensi…
A ferromagnetic semiconductor, rutile (Ti,Co)O2, exhibits anomalous Hall effect at room temperature. Strong dependence of the anomalous Hall effect, as well as the magneto-optic response, on the carrier concentration suggests carrier induced ferromagnetism in this compound. Both ferromagnetic responses are caused by t…
Here we employ both Fe K and L2,3 edge x-ray absorption near-edge structure (XANES) spectroscopy techniques to clarify that iron in the B-site ordered double-perovskite halfmetal, Sr2FeMoO6.0, possesses a mixed-valence state, FeII/III, and accordingly molybdenum a mixed MoV/VI valence state. A reliable interpretation…
In this paper, we describe the synthesis of tailormade cobalt and manganese oxides by a two-step preparation method. The first step consists of precipitating metal alkoxide powders from aliphatic polyalcohol solutions of salts. Their particle size, composition, and morphology can be independently tuned by controlling…
We analyze the energetics of spherelike micellar phases in diblock copolymers in terms of well-studied, geometric quantities for their lattices. We argue that the A15 lattice with Pm3;n symmetry should be favored as the blocks become more symmetric and corroborate this through a self-consistent field theory. Because p…
Auger rates are calculated for CdSe colloidal quantum dots using atomistic empirical pseudopotential wave functions. We predict the dependence of Auger electron cooling on size, on correlation effects (included via configuration interaction), and on the presence of a spectator exciton. Auger multiexciton recombination…
We propose a bond order potential for carbon with built-in long-range interactions. The potential is defined as the sum of an angular and coordination dependent short-range part accounting for the strong covalent interactions and a radial long-range part describing the weak interactions responsible, e.g., for the inte…
Transparent trilayered oxide films of ZnO/NiO/indium tin oxide were heteroepitaxially grown on a YSZ (111) substrate by pulsed-laser deposition combined with a solid-phase-epitaxy technique, and were processed to fabricate a p-NiO/n-ZnO diode. The diode exhibited a clear rectifying I–V characteristic with an ideality…
Ceramic fabrication processes - an introductory overview synthesis of powders powder characterization science of colloidal processing sol-gel processing powder consolidation and forming of ceramics sintering of ceramics - fundamentals theory of viscous sintering grain growth and microstructural control liquid-phase si…
Ungewöhnliche strukturelle und magnetische Eigenschaften charakterisieren neuartige gemischtvalente Co2+-Co3+-Oligooxocobaltate, die nach dem Azid-Nitrat-Verfahren zugänglich sind. In diesen Anionen besteht eine ausgeprägte Hierarchie der magnetischen Austauschwechselwirkungen (siehe Bild).
Results of molecular dynamics simulations on vibrational properties of zeolite ZSM-5-based amorphous solids are presented. The vibrational density of states was determined for different extents of amorphization. Amorphization is found to smoothen the density of states and leads to especially large effects in the high-…
Novel polyphenylene and polythiophene derivatives that have N,N ‘ -diphenyl-1,4-phenylenediamine (PDA) units were synthesized using the palladium-catalyzed Suzuki coupling or cross coupling. Each obtained polymer has good redox activity, and the polyphenylene derivatives have two redox couples in acetonitrile that con…
In-situ scanning tunneling microscopy (STM) has been used to follow the growth mode of gold clusters on TiO 2 (110) single crystals at room temperature on a cluster-by-cluster basis. Using carefully annealed TiO 2 (110) surfaces with a relatively low defect density it is possible to isolate cluster growth on step site…