Materials Literature
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A series of nanosized gold supported on CeO 2, MnO 2, and MnO 2 −CeO 2 composite oxides have been prepared by a deposition−precipitation (DP) method and the effects of Mn/Ce atomic ratio on Au/MnO 2 −CeO 2 catalysts and calcination temperature after loading gold for preferential oxidation of CO (PROX) in H 2 stream ha…
Abstract The controlled tuning of the characteristic dimensions of two‐dimensional arrays of block‐copolymer reverse micelles deposited on silicon surfaces is demonstrated. The polymer used is polystyrene‐ block ‐poly(2‐vinylpyridine) (91 500‐ b ‐105 000 g mol –1 ). Reverse micelles of this polymer with different aggr…
In this paper, we study triply periodic surfaces with minimal surface area under a constraint in the volume fraction of the regions (phases) that the surface separates. Using a variational level set method formulation, we present a theoretical characterization of and a numerical algorithm for computing these surfaces.…
Effects of superconducting fluctuations on the Fulde-Ferrell (FF) state are discussed in a spatially isotropic three-dimensional superconductor under a magnetic field. For this system, Shimahara recently showed that within the phenomenological Ginzburg-Landau theory, the long-range order of the FF state is suppressed…
Non-linear properties of tetragonal tungsten bronze materials are related to solid-state chemistry. This family is very prolific, with its five different cationic or anionic crystallographic sites. The physical characteristics are correlated to composition and chemical bonding. Some effective or potential applications…
The difference between the surface and the bulk shell of Ce(x)Pr(1-x)O(2-delta) mixed oxides was studied by Raman spectroscopy with four different excitation lasers. Two Raman peaks appear at 465 and 570 cm(-1) under all of the four lasers. The former is attributed to the Raman active F(2g) mode of CeO2, while the lat…
The alignment of the Fermi level of a metal electrode within the gap of the hi ghest occupied (HOMO) and lowest unoccupied orbital (LUMO) of a molecule is a key quantity in molecular electronics, which can vary the electron transparency of a single molecule junction by orders of magnitude. We present a quantitative an…
Using density functional theory we investigate the occurrence of superconductivity in AC$_6$ with A=Mg,Ca,Sr,Ba. We predict that at zero pressure, Ba and Sr should be superconducting with critical temperatures (T$_c$) 0.2 K and 3.0 K, respectively. We study the pressure dependence of T$_c$ assuming the same symmetry f…
Among the mechanisms for lattice structural deformation, the electron-phonon interaction mediated Peierls charge-density-wave (CDW) instability in single band low-dimensional systems is perhaps the most ubiquitous. The standard mean-field picture predicts that the CDW transition occurs at all fillings and all values o…
We investigate theoretically the electronic structure and transport for a two-level quantum wire with Rashba spin-orbit coupling (SOC) under the irradiation of an external laser field at low temperatures. The photon-induced transitions between SOC-splitted subbands with the same lateral confinement quantum numbers and…
The dominant charge state for the Ga vacancy in GaAs has been the subject of a long debate, with experiments proposing $-$1, $-$2 or $-$3 as the best answer. We revisit this problem using {\it ab initio} calculations to compute the effects of temperature on the Gibbs free energy of formation, and we find that the ther…
To study the reaction kinetics at the anode of solid‐oxide fuel cells, a nickel stripe pattern was prepared on the surface of yttria‐stabilized zirconia (YSZ) [8 mole percent (m/o) ] by an ionized cluster beam (ICB) method and photolithography. Due to grain growth of nickel film at high temperatures, the minimum possi…
The vibrational modes of some single-wall carbon nanotube (SWNT) intramolecular junctions (IMJs) have been calculated using the latest Brenner reactive empirical bond order (REBO) potential, based on which their nonresonant Raman spectra have been further calculated using the empirical bond polarizability model. It is…
Direct magnetization measurements of thin gold films are presented. These measurements integrate the signal from the thin film under study and the magnetic contribution of the film's interface with the substrate. The diamagnetic contribution to the signal from the bulk substrate is of the same order as the noise level…
The anomalous Hall effect is investigated experimentally and theoretically for ferromagnetic thin films of Mn$_5$Ge$_3$. We have separated the intrinsic and extrinsic contributions to the experimental anomalous Hall effect, and calculated the intrinsic anomalous Hall conductivity from the Berry curvature of the Bloch…
Changes in chemical properties of nanoscale particles include quantum size effect, changes in the cell parameters and lattice symmetry, and surface and interface effects. In the case of layered double hydroxides (LDHs), surface and interface effects dominate for nanoparticles of MgAl LDHs. Using TEM micrographs of nan…
We have investigated the effect of nanometric grain size on magneto- and electronic-transport properties of single-phase, nanocrystalline, granular ${\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}\mathrm{Mn}{\mathrm{O}}_{3}$ samples having an average grain size in the nanometric regime $(14--27\phantom{\rule{0.3em}{0ex}}\mathr…
We have studied the morphology of blends of PS/PMMA, PC/SAN24, and PMMA/EVA and compared the morphologies with and without modified organoclay Cloisite 20A or Cloisite 6A clays. In each case we found a large reduction in domains size and the localization of the clay platelets along the interfaces of the components. Th…
Several approaches are proposed to enhance the spin splitting at the conduction band edge and consequently induce free-electron-mediated stabilization of ferromagnetic semiconductors. We show that kinetic $s\text{\ensuremath{-}}d$ coupling can be introduced through chemical ordering and/or strain. We find that quantum…
In this study, we report on the lipid tail molecular shape/size effect on the mesophase self-assembly behaviors of various cationic lipids complexed with double-stranded DNA. The molecular shape of the cationic lipids was tailored from rodlike (a cyanobiphenyl imidazolium salt) to discotic (a triphenylene imidazolium…