Materials Literature
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The electrical responses of vanadium pentoxide nanowires to helium gas and environmental pressures are demonstrated. The devices feature well-aligned nanowires that are oriented by electrophoresis technique in the submicron scale. The electrical conductance is found to increase and decrease upon exposure to helium gas…
A novel processing route for developing open‐cell, microcellular SiC ceramics has been developed. The strategy adopted for making microcellular SiC ceramics involved the following: (i) fabricating a formed body from a mixture of polysiloxane, phenol resin (used as a carbon source), polymer microbeads (used as sacrific…
Gasoline from methane: Methane can be activated nonoxidatively and converted into higher hydrocarbons over bifunctional zeolite catalysts at low temperatures (≤600 °C; see scheme). The amount of methane converted per mole of methanol by this process can meet or even exceed 1 mol. This approach could potentially lead t…
An experimental investigation of long-ranging surface plasmon-polariton waves guided along Bragg gratings fabricated from a thin finite width Au film embedded in a homogeneous background dielectric is reported. The operation of four grating families is demonstrated near the free space optical wavelength of 1550 nm. Th…
A silver‐based joining technique referred to as reactive air brazing has been recently developed for joining high‐temperature structural ceramic components of the type used in gas turbines, combustion engines, heat exchangers, and burners. It was found that additions of copper oxide to silver exhibit a tremendous effe…
The electronic structure and magnetic properties of Mn-doped Ge, GaAs, and ZnSe nanocrystals are investigated using real space ab initio pseudopotentials constructed within the local spin-density approximation. The ferromagnetic and half-metallicity trends found in the bulk are preserved in the nanocrystals. However,…
Pattern formation during silica biomineralization in diatoms appears to depend on long-chain polyamines as well as proteins covalently modified with polyamines (silaffins). Recently, the complete genome of the diatom Thalassiosira pseudonana has been sequenced making this species an attractive model organism for futur…
The geometrical and electronic structures of the 4 \AA{}-diam perfect and deformed (5, 3) single-walled gold nanotube (SWGT) have been studied based on the density-functional theory in the local-density approximation (LDA). The calculated relaxed geometries show clearly significant deviations from those of the ideally…
Quasicrystals have a higher degree of rotational and point-reflection symmetry than conventional crystals. As a result, quasicrystalline heterostructures fabricated from dielectric materials with micrometer-scale features exhibit interesting and useful optical properties including large photonic bandgaps in two-dimens…
Holographic optical tweezers use computer-generated holograms to create arbitrary three-dimensional configurations of single-beam optical traps useful for capturing, moving and transforming mesoscopic objects. Through a combination of beam-splitting, mode forming, and adaptive wavefront correction, holographic traps c…
Results of magnetization, magnetotransport and Mossbauer spectroscopy measurements of sequentially evaporated Fe-Ag granular composites are presented. The strong magnetic scattering of the conduction electrons is reflected in the sublinear temperature dependence of the resistance and in the large negative magnetoresis…
We present a computational study of the dynamic behavior of a Ziff-Gulari-Barshad model of CO oxidation with CO desorption on a catalytic surface. Our results provide further evidence that below a critical desorption rate the model exhibits a non-equilibrium, first-order phase transition between low and high CO covera…
We consider the proximity effects in hybrid superconductor (S) - ferromagnet (F) structures drawing attention to the induced ferromagnetism of the S metal. The analysis is based on a quasiclassical theory of proximity effect for metals in the dirty limit conditions. It is shown that, below the superconducting critical…
The electronic structure of Cu hexafluoroacetylacetonate, crystallized with a stable nitronyl nitroxide radical [Ovcharenko et al., Russ. Chem. Bull. 53, 2406 (2004)], is calculated from first principles within the density functional theory using the SIESTA method, in two magnetic configurations reflecting parallel or…
The dependencies on strain and oxygen vacancies of the ferroelectric polarization and the weak ferromagnetic magnetization in the multiferroic material bismuth ferrite, $\mathrm{Bi}\mathrm{Fe}{\mathrm{O}}_{3}$, are investigated using first principles density functional theory calculations. The electric polarization is…
We report on the temperature dependence of the photoluminescence (PL) spectrum and of the PL relaxation dynamics for colloidal $\mathrm{Cd}\mathrm{Se}∕\mathrm{Zn}\mathrm{S}$ core/shell quantum dots (QDs) embedded in an inert polystyrene matrix. We demonstrate that the confinement energy in the QDs is independent of th…
Abstract Summary: Rapid dissolution of cellulose in LiOH/urea and NaOH/urea aqueous solutions was studied systematically. The dissolution behavior and solubility of cellulose were evaluated by using 13 C NMR, optical microscopy, wide‐angle X‐ray diffraction (WAXD), FT‐IR spectroscopy, DSC, and viscometry. The experime…
Effect of Ti doping on the electrical transport and magnetic properties of layered Na0.8Co1-xTixO2 compounds has been investigated. The lattice parameters a and c increase with x. A minor amount of Ti doping results in a metal-insulator transition at low temperatures. For samples with x > 0.03, the variable-range hopp…
Thermally stimulated process such as evaporation, phase transition, or solid-liquid transition of a solid consumes each a certain portion of the solid cohesive energy that is the sum of bond energy over all the coordinates of all the involved atoms. Generally, the critical temperatures for such processes drop with sol…
The segmental and terminal dynamics of the individual components in miscible blends of polyisoprene (PI) and polystyrene (d 3 PS) were characterized over a wide temperature range. Though the system has a large positive Flory−Huggins interaction parameter χ ∼ 0.1, it is miscible in the temperature range of study due to…