Materials Literature
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Thermolysis of gold(I) thiolate complex, [C14H29(CH3)3N][Au(SC12H25)2], at 180 degrees C for 5 h under an N2 atmosphere produces novel gold nanoparticles passivated by alkyl groups derived from the precursor complex, the TEM image of which shows spherical particles with average diameter 26 nm.
Analytical expressions in the time and frequency domains are derived for non-Debye relaxation processes. The complex frequency-dependent susceptibility function for the stretched exponential relaxation function is given for general values of the stretching exponent in terms of H-functions. The relaxation functions cor…
A novel heterospin system, [(CuL)2Gd(TCNQ)2].TCNQ-.CH3OH.2CH3CN, is obtained by reacting the mononuclear complex, [CuL], with gadolinium(III) nitrate, followed by the substitution of the nitrato ions with anionic organic radicals.
The development of new techniques such as the molecular beam epitaxy have enabled the growth of thin films of materials presenting novel properties. Recently it was made possible to grow a CrAs thin-film in the zinc blende structure. In this contribution, the full-potential screened KKR method is used to study the ele…
Time-resolved optical spectroscopy of collective and single-particle excitations of $1T\ensuremath{-}{\mathrm{TaS}}_{2}$ and $2H\ensuremath{-}{\mathrm{TaSe}}_{2}$ reveals the presence of a large gap in the excitation spectrum on the femtosecond time scale, associated with the formation of various degrees of charge-den…
Syntheses, optical spectroscopy, potentiometric studies, and electronic structural calculations are reported for two classes of conjugated (porphinato)metal oligomers that feature a meso-to-meso ethyne-bridged linkage topology. One set of these systems, bis[(5,5'-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphi…
The performances of oxidation and SCR catalysts were investigated individually and as a combined system for the removal of NO x by ammonia. Experiments were carried out with synthetic gas mixtures matching the composition of diesel exhaust. Introducing an oxidation catalyst upstream of the SCR catalyst enhances the re…
In this paper, treatment of 1,1'-(1,4-butanediyl) bis-1H-benzotriazole (bbbt) and KSCN with Co(II), Mn(II), or Cd(II) afforded three two-dimensional rhombohedral grid coordination polymers [M(bbbt)(2)(NCS)(2)](n)(M = Co, 1; Mn, 2; Cd, 3). The two-dimensional rhombohedral grids are parallel to the crystallographic ac p…
Intracellular Ca(2+) plays an important role in signal transduction, and we are developing new MRI techniques to study its regulation in living animals. We have reported on an MRI contrast agent (DOPTA-Gd) where the relaxivity of the complex is controlled by the presence or absence of the divalent ion Ca(2+). By struc…
The effect of chain extenders on the morphology development in flexible polyurethane foam has been studied by small-angle X-ray scattering (SAXS), FTIR spectroscopy, and rheometry. Four chain extenders, diethanolamine (DEOA), 1,2-ethylene diol (EDO), glycerol, and 2-(methylamino)ethanol (MAE), were studied in a standa…
Magnetic dc susceptibility $(\ensuremath{\chi})$ and electron-spin resonance (ESR) measurements in the paramagnetic regime, are presented. We found a Curie-Weiss behavior for $\ensuremath{\chi}(\mathrm{T})$ with a ferromagnetic $\ensuremath{\Theta}=446(5) \mathrm{K}$ and ${\ensuremath{\mu}}_{\mathrm{eff}}=4.72(9){\ens…
A differential cluster variation method (DCVM) is proposed for analysis of spinoidal decomposition in alloys. In this method, lattice symmetry operations in the presence of an infinitesimal composition gradient are utilized to deduce the connection equations for the correlation functions and to reduce the number of in…
Conjugated polyelectrolytes are conjugated polymers that feature ionic side groups which render the materials soluble in water and other polar solvents. In this review we summarize recent work which has been carried out to synthesize a variety of new conjugated polyelectrolyte structures, including those with poly(par…
Using a plane wave pseudopotential approach to density functional theory we investigate the electron localization length in various oxides. For this purpose, we first set up a theory of the band-by-band decomposition of this quantity, more complex than the decomposition of the spontaneous polarization (a related conce…
At hole concentrations below x=0.4, Ba_(1-x)K_xBiO_3 is non-metallic. At x=0, pure BaBiO3 is a Peierls insulator. Very dilute holes create bipolaronic point defects in the Peierls order parameter. Here we find that the Rice-Sneddon version of Peierls theory predicts that more concentrated holes should form stacking fa…
Detailed KMC-MD (kinetic Monte Carlo-molecular dynamics) simulations of hyperthermal energy (10-100 eV) copper homoepitaxy have revealed a re-entrant layer-by-layer growth mode at low temperatures (50K) and reasonable fluxes (1 ML/s). This growth mode is the result of atoms with hyperthermal kinetic energies becoming…
The use of reactive mechanical grinding (MG under H2) of magnesium powder improves the hydrogen sorption properties. The hydrogenation of Mg starts in situ during the milling process, thus circumventing the activation procedure that is generally required for Mg. The effects of the addition of various elements or compo…
Catalysts have been prepared by subliming CoCl 2 or CoBr 2 vapor onto the H form of the zeolite MFI, followed by replacing the halide ions by OH groups and subsequent heat treatments. The Co sites have been characterized by EXAFS and XANES spectra at liquid nitrogen temperature. The data are correlated with the H 2 -T…
A series of water-dispersible, surface-active poly(fluorinated oxetane)s was prepared by ring-opening polymerization of fluorinated oxetane monomers using Lewis acid catalysis. The fluorinated oxetane monomers are made by phase-transfer catalytic reaction of a fluorinated alcohol with 3-bromomethyl-3-methyloxetane. Wa…
An efficient convergent synthesis of first- and second-generation aryl-/alkyl-type nonpolar dendrons via Suzuki cross-coupling is described. The dendrons carry either one or two benzyl-protected hydroxyalkyl groups/terminus. Iododesilylation reactions of aryltrimethylsilanes with iodo chloride are used as a tool for t…