Materials Literature
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In the present article, a detailed study of the optical properties of the Er-doped Si nanocrystals system, obtained through ion implantation of Er in samples containing Si nanocrystals formed by plasma enhanced chemical vapor deposition is reported. In particular, we present a phenomenological model based on an energy…
Nonlinear optical response and optical coherence of excitons in semiconductor dense quantum dots in GaAs single quantum wells has been studied by using photon echo techniques. At low temperatures, the optical coherence is estimated to be 2 ns from the decay curve in the photon echo signal. Rabi oscillations are also o…
The superconducting properties of copper-sheathed MgB2 wires fabricated by conventional powder-in-tube techniques and the in-situ reaction procedure are analysed. The influence of the processing conditions and initial (1+x)Mg + 2B (x = 0, 0.1, 0.2) proportions of the precursors on the critical current values of the wi…
Cu(OH) 2 and CuO nanoribbon arrays aligned approximately perpendicular to copper substrate surfaces are synthesized by the solution-treatment and subsequent heat-treatment processes. The Cu(OH) 2 nanoribbons are fabricated by a simple coordination self-assembly method in an alkaline solution with Cu 2+ ions being from…
We report different approaches to the synthesis of size series of highly luminescent CdSe/CdS core−shell nanocrystals. The mixture of hexadecylamine (HDA)−trioctylphosphine oxide (TOPO)−trioctylphosphine (TOP) as stabilizing solvent was found to be very suitable for one-pot synthesis of nearly monodisperse CdSe nanocr…
Prepared within biocompatible poly(amidoamine) dendrimer hosts, blue emitting Au8 nanodots were prepared with fluorescence quantum yields more than 100 times larger than any previously prepared. The strong size-dependent blue emission from these from monodisperse Au8 nanodots was measured to be 41% in aqueous solution…
The local environment surrounding ferromagnetically ordered Mn in Mn/GaAs digital layers and (Ga, Mn)As random alloys has been selectively probed using a combination of local structural information obtained by x-ray magnetic circular dichroism (XMCD) and extended x-ray absorption fine structure (EXAFS) techniques. The…
Melting of semicrystalline polymers typically occurs over a temperature range of 10 °C or more, throughout which the long period L increases by 50%−100%. Less recognized is the evolution of the small-angle X-ray scattering (SAXS) pattern from peaked to monotonic before the final stages of melting. These two features a…
The structure evolution of iPS during isothermal cold-crystallization and subsequent melting processes is studied by in situ monitoring its FTIR spectra. Through following the intensity changes of the characteristic bands associated with its crystalline status and 3 1 helix conformation chains, the multiple melting be…
The paper explores the capacity of small angle neutron neutron scattering (SANS) to characterize the dispersion of an exchanged clay in an organic solvent. As an illustration, results are reported for 1% and 2% by mass suspensions of a representative commercial complex, known as Cloisite, C15A in toluene. C15A is prep…
Aromatic poly(ether−ketone)s having pendant carboxyl groups have been obtained by direct, one-pot, Friedel−Crafts copolycondensation of 4,4‘-diphenoxybenzophenone with a mixture of terephthaloyl chloride (TC) and trimellitic anhydride acid chloride (TAAC), over a wide range of TAAC/TC molar ratios, in the presence of…
Abstract A polypyrrole (PPy) film, prepared electrochemically from methyl benzoate solution of tetra-n-butylammonium tetrafluoroborate on Ti electrode, showed 12.4% strain and 22 MPa stress induced electrochemically in NaPF6 aqueous solution. The large strain and stress may be due to doping-dedoping of anion and a con…
Nanocrystalline films of Au, Ag, and Cu have been prepared at the toluene−water interface by the interaction of metal−triphenylphosphine complexes in the organic layer with partially hydrolyzed tetrakishydroxymethylphosphonium chloride in the aqueous layer. The nanocrystals have been characterized by a host of microsc…
Double wall carbon nanotubes were prepared by vacuum annealing of single wall carbon nanotubes filled with C60. Strong evidence is provided for a highly defect free and unperturbed environment in the interior of the tubes. This is concluded from unusual narrow Raman lines for the radial breathing mode of the inner tub…
Cyclic mechanical strain has been demonstrated to enhance the development and function of engineered smooth muscle (SM) tissues, and it would be necessary for the development of the elastic scaffolds if one wishes to engineer SM tissues under cyclic mechanical loading. This study reports on the development of an elast…
We studied giant magnetoimpedance (GMI) effect in commercial crystalline Mumetal, with the emphasis to sample thickness dependence and annealing effects. By using appropriate heat treatment one can achieve GMI ratios as high as 310%, and field sensitivity of about 20%/Oe, which is comparable to the best GMI characteri…
Carbon nanotubes (CNTs)−magnetite nanocomposite with 20−30-nm magnetite particles attached onto CNTs has been successfully prepared for the first time by in situ solvothermal synthesis from the precursor of Fe−urea coordination complex (Fe[(NH 2 ) 2 CO] 6 (NO 3 ) 3 ) and CNTs. The effects of CNTs and various processin…
Morphological instability of the solid-liquid interface occuring in a crystal growing from an undercooled thin liquid being bounded on one side by a free surface and flowing down inclined plane is investigated by a linear stability analysis under shear flow. It is found that restoring forces due to gravity and surface…
The thermal conductivity of nanometric objects or nanostructured materials can be determined using non equilibrium molecular dynamics (NEMD) simulations. The technique is simple in its principle, and resembles a numerical guarded hot plate experiment. The 'sample' is placed between a hot source and a cold source consi…
CMK-5 ordered mesoporous carbons that consist of two-dimensional (2-D) hexagonal arrays of pipes were synthesized using furfuryl alcohol as a carbon source and SBA-15 aluminosilicate of 2-D hexagonal structure as a template. External and internal pipe diameters were varied concomitantly by using SBA-15 templates with…