Materials Literature
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La 0.67 Ca 0.33 MnO 3 (LCMO) nanoparticles were prepared by the sol–gel method. The composite samples of (LCMO) x /(ZrO 2 ) 1− x were obtained by mixed LCMO and ZrO 2 powders and sintered at 1300°C. Detailed studies of magnetic and magnetotransport properties for composite samples have been performed. The x-ray diffra…
We have investigated stable adsorption geometries of fluorine atoms on a single-walled carbon nanotube (SWNT) using density-functional calculations. Chemisorption of fluorine atoms induces heavy strain on the tube wall, giving rise to one of the C-C back bonds of 1.54 \AA{}, single bonded similar to that of diamond. W…
Two effects induced by increasing power density of a probe laser beam are discovered in Raman spectra of single-wall nanotubes: the irreversible disappearance of the 'breathing' Raman modes of small-diameter nanotubes (0.8 — 1 nm) and the reversible appearance of additional 'breathing' modes from nanotubes with diamet…
A particular structural feature of zeolites relative to other aluminosilicate materials, and other crystalline materials in general, is the existence of channels and/or cavities linked by channels. One of the characteristics that distinguishes zeolites from other porous materials is their variety of pore sizes and sha…
Amorphous carbon nitride films deposited by rf magnetron sputtering were annealed up to 900°C in vacuum for 1 h. The variations of composition and bonding structure of the films were investigated by Fourier transformation infrared, Raman spectroscopy and x-ray photoelectron spectroscopy. The results showed that a grea…
Abstract New Schiff bases of 2,4‐dihydroxybenzaldehyde with siloxane‐α,ω‐diamines having different numbers of siloxane units in the chain have been synthesized and characterized by spectroscopy, elemental and thermal analyses. These azomethines were found to form complexes readily with copper(II), nickel(II), cobalt(I…
Dielectric spectroscopy, encompassing 13 decades of frequency, was used to investigate local segmental relaxation in polyvinylmethylether (PVME). Measurements were obtained over a 110 degree range of temperatures, at pressures up to 725 MPa. At atmospheric pressure, time-temperature superpositioning is valid; however,…
We describe the synthesis and characterization of a thermoreversibly cross-linked biopolymer microgel based on protein, DNA, and peptide nucleic acid (PNA) components. The DNA assembles into a trifunctional three-way junction (TWJ) with single-stranded overhangs. PNA oligomers complementary to these overhangs and bear…
Abstract Reaction of AlCl 3 with {Me 2 SiO} n (Dow‐Corning high‐vacuum grease) at an Al : Si ratio of 1 : 1 in hexane at room temperature yielded a large crop of colorless crystals of [{ClSiMe 2 OAlCl 2 } 2 ], which were characterized by single‐crystal X‐ray diffraction and NMR. These crystals hydrolyzed on an aluminu…
The band gap tuning of amorphous silicon carbon nitride thin (a-SiCN) film was demonstrated in the range of 2.3–3.0 eV by pulsed laser deposition using mixed targets. a-SiCN films were grown on silicon and quartz glass substrates at room temperature in a vacuum. Targets were fabricated by compacting a mixture of silic…
The structure and stability of the (B 12 N 12 ) n ( n = 1, 2) cages have been computed at the B3LYP level of density functional theory. The most stable B 12 N 12 cage is the T h symmetrical structure with six isolated squares. The dimerization pattern of B 12 N 12 differs strongly from those of C 60 and C 20 . The mos…
X-ray charge densities of Al-based icosahedral quasicrystalline approximant crystals $\ensuremath{\alpha}\ensuremath{-}\mathrm{AlReSi},$ $\ensuremath{\alpha}\ensuremath{-}\mathrm{AlMnSi},$ and ${\mathrm{Al}}_{12}\mathrm{Re}$ were observed by a combination of the maximum entropy method with the Rietveld method. We succ…
The layered double hydroxides (LDHs) Zn 2 Al(OH) 6 Cl· n H 2 O, Zn 2 Cr(OH) 6 Cl· n H 2 O, and Cu 2 Cr(OH) 6 Cl· n H 2 O have been shown to undergo staged intercalation reactions with succinate and tartrate anions. Monitoring the process in situ using energy-dispersive X-ray diffraction reveals the formation of second…
Colloidal dispersions of Mg/Al LDH platelets show liquid-crystal phase at a certain particle concentration. Threaded texture observed with polarized microscopy indicated it was typical of a nematic phase, which can often be found in traditional liquid crystals.
Various vacancy-impurity complexes that are believed to account for the deactivation of As in highly n-doped silicon are investigated using the density functional theory. The electronic structure and defect levels of these impurities are determined, both of which are crucial for the understanding and modeling of the d…
The viability of 1,3-dipolar cycloadditions of a series of 1,3-dipolar molecules (azomethine ylide, ozone, nitrone, nitrile imine, nitrile ylide, nitrile oxide, diazomethane, and methyl azide) onto the sidewalls of carbon nanotubes has been assessed theoretically by means of a two-layered ONIOM approach. The theoretic…
We have carried out a direct measurement of the degree of spin polarization ($\mathbit{P}$) of the magnetic semiconductor ${\mathrm{G}\mathrm{a}}_{1\ensuremath{-}x}{\mathrm{M}\mathrm{n}}_{x}\mathrm{A}\mathrm{s}$ using Andreev reflection spectroscopy. Analyses of the conductance spectra of high transparency ${\mathrm{G…
Electrochemical potential dependence of Raman intensity of isolated single-walled carbon nanotubes (SWNT) on gold electrode in aqueous solution was investigated employing in situ resonant confocal micro Raman spectroscopy. Absolute potential of the Fermi level of individual tubes was estimated from the potential depen…
The generation of nanoscale interconnects and supramolecular, hierarchical assemblies enables the development of a number of novel nanoscale applications. A rational approach toward engineering a robust system is through chemical recognition. Here, we show the in situ mineralization of crystalline CdTe quantum dots on…
Metallic nanowires of cobalt, copper, and iron oxide magnetite (Fe 3 O 4 ) have been synthesized within the pores of mesoporous silica using a supercritical fluid inclusion technique. The mesoporous matrix provides a means of producing a high density of stable, hexagonally ordered arrays of highly crystalline nanowire…