Materials Literature
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The local environment of Cm3+ in a borosilicate glass has been probed by a combination of laser spectroscopy, structural modeling, and extended x-ray absorption fine structure (EXAFS) spectroscopy. The Stark splitting for the Cm f–f state transitions is significantly larger than the inhomogeneous line broadening that…
Magnetic and magnetostrictive properties have been investigated for amorphous (Tb0.27Dy0.73)(Fe1−xCox)2 thin films. An increase in the 3d magnetic moment due to the enhancement of T–T interactions in substituted (Fe, Co) alloys was found. This leads to stronger R–(Fe, Co) exchange energies and then to enhancements of…
The electronic properties and the crystal structure of layered perovskite-related niobates ${\mathrm{Sr}}_{1\ensuremath{-}y}{\mathrm{La}}_{y}{\mathrm{NbO}}_{3.5\ensuremath{-}x}$ can be tuned by gradually changing the oxygen stoichiometry. We have studied the electronic structure of this series in detail by angle-integ…
A novel segmented block copolymer, containing polyethylene glycol segment and GlyAlaGlyAla sequence derived from B. mori silk, has been prepared as a model for silk-based materials using both solution and interfacial techniques. Inherent viscosity, size exclusion chromatography, and light-scattering measurements gave…
The changes in the photoconductivity of hydrogenated tetrahedral amorphous carbon (ta-C:H) with nitrogen incorporation were studied. Low level nitrogen incorporation improves the photoconductivity, by shifting the Fermi level upwards in the band gap. Films with a photosensitivity of about 200 at room temperature under…
Novel thermoplastic elastomers (TPEs) consisting of poly(isobutylene-b-indene) (PIB-b-PInd) arms radiating from hexamethylcyclohexasiloxane (D) cores were prepared, characterized, and their properties investigated. The syntheses of these star-blocks involved the linking by hydrosilation of PInd-b-PIBCH2CHCH2 prearm…
The photophysical and structural features of a series of linear, Aib-based peptides were investigated in methanol solution. These compounds have the general formula P(Aib) n N, where Aib is α-aminoisobutyric acid, N naphthalene, and P the monomethylated protoporphyrin IX, the two latter molecules being covalently atta…
First-principles pseudopotential calculations are reported for the lattice distortion and electronic properties of the Al substitutional defect in $\ensuremath{\alpha}$ quartz. We determine microscopical properties of the center such as Al coordination, symmetry of the distorted lattice and defect-induced electronic s…
The polycarbyne polymer films were coated on silicon substrates and then irradiated by a pulsed Nd:yttrium–aluminum–garnet laser (λ=532 nm) with various fluences in argon gas atmosphere. Significant changes in microstructures and chemical bonding (sp3/sp2) during laser treatment were investigated by Raman spectroscopy…
The molecular structure of the formal iron(IV) porphyrinate derivative, [[Fe(TTP)]2N]SbCl6 (TTP = tetratolylporphyrinate), is reported. The structural parameters are compared to the previously reported species [Fe(TPP)]2N, in which the iron oxidation state is +3.5. Both the equatorial and axial bond distances in [[Fe(…
The helical twisting power βM determines the pitch of the chiral nematic phase produced when a nematic liquid crystal is doped with a low concentration of chiral solute molecules. Molecules with large βM values have potential applications in electro-optic displays and in optical data storage. This paper describes a ne…
The results of a detailed molecular-dynamics study of the growth of amorphous carbon $(a\ensuremath{-}\mathrm{C})$ are reported. Carbon atoms with kinetic energies between 10 and 150 eV are deposited on $a\ensuremath{-}\mathrm{C}$ surface originating from bulk $a\ensuremath{-}\mathrm{C}.$ Earlier simulation results of…
We present the results of molecular dynamics simulations of SPC/E water confined in a realistic model of a silica pore. The single-particle dynamics have been studied at ambient temperature for different hydration levels. The confinement near the hydrophilic surface makes the dynamic behaviour of the liquid strongly d…
The dynamics of lithium ions in lithium bismuthate glasses have been studied in the frequency range from 10 Hz to 2 MHz and in the temperature range from 323 to 543 K. The composition dependence of the dc (direct current) conductivity has been explained in terms of the structure of bismuthate glasses. The activation e…
We report the development of compound dyes which have tunable emission wavelengths, from 520 to 680 nm, and simultaneously tunable excited-state lifetimes, ranging from 50 to 500 μs. Future work is expected to extend these ranges yet further. The compound dyes are made of a lanthanide donor with a millisecond lifetime…
The preparation, X-ray crystal structure, and magnetic properties of alternating 1,1- and 1,3-azido-bridged copper(II) complex [Cu(4,4'-dmbpy)(N3)2]n (1, 4,4'-dmbpy = 4,4'-dimethylbipyridine) have been reported. It crystallizes in triclinic system, space group P1, a = 7.9903(1) A, b = 9.3545(9) A, c = 10.754(2) A, alp…
X-ray photoemission spectra of Ge and ${\mathrm{GeO}}_{2}$ have been collected using high-energy photons ${(E}_{\ensuremath{\gamma}}=13.6\mathrm{keV}$ and ${E}_{\ensuremath{\gamma}}=11.85\mathrm{keV}).$ The experiment was carried out using a high brilliance undulator source of the European Synchrotron Radiation Facili…
Transparent poly(methyl acrylate-co-itaconic anhydride)/SiO2 hybrid materials were prepared from methyl acrylate-itaconic anhydride copolymer and tetraethoxysilane (TEOS) with the coupling agent (3-aminopropyl)triethoxysilane (APTES) via a sol–gel process. The covalent bonds between the organic and inorganic phases we…
The development of spin–electronic devices based on oxide magnets is reviewed. After a discussion of colossal magnetoresistance in magnetic perovskites and an introduction of the concept of half metallicity, spin–electronic devices such as ferromagnetic tunnel junctions, grain–boundary junctions, ferromagnet–supercond…
Positive magnetoresistance is measured in the low-magnetic fields in multiwalled carbon nanotubes, and interpreted as antilocalization in the weak-localization regime. The analysis shows that the weak antilocalization effect is related to the local interfacial electric field as a genuine property of the large curvatur…