Materials Literature
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Vertically well-aligned (Zn,Mn)O nanorods (see Figure) that show ferromagnetic behavior at room temperature have been grown on sapphire substrates by chemical vapor deposition. The high optical quality of the nanorods has been demonstrated by photoluminescence spectroscopy. These nanowires may find use in future nanos…
Glasses and melts in the system (NaPO3)(1-x)(Al(PO3)3)x were studied with the aim of obtaining information about the structure on the next larger scale beyond the PO4 group. Magic angle spinning NMR was applied to the pure NaPO3 glass and Raman scattering to systems with x = 0.00, 0.03, 0.06, 0.15, and 0.60 in the tem…
Abstract Summary: A CF 3 ‐containing diamine, 4,4′‐bis(4‐amino‐2‐trifluoromethylphenoxy)biphenyl ( I ), was synthesized from 4,4′‐biphenol and 2‐chloro‐5‐nitrobenzotrifluoride. The imide‐containing diacids ( V a‐b and VI a‐l ) were prepared by condensation reaction of amino acids, aromatic diamines and trimellitic anh…
[reaction: see text] A novel application of photochromic molecules is to mimic physiological oscillatory calcium signals by reversibly binding and releasing calcium ions in response to light. Substituent changes on the largely unexplored photochromic bisbenzospiropyran scaffold led to significant changes in thermal fa…
The interaction has been studied in aqueous solutions between a negatively charged conjugated polyelectrolyte poly{1,4-phenylene-[9,9-bis(4-phenoxybutylsulfonate)]fluorene-2,7-diyl} copolymer (PBS-PFP) and several cationic tetraalkylammonium surfactants with different structures (alkyl chain length, counterion, or dou…
Abstract In this study, polypropylene (PP)/wood flour composites foams with an average cell size lower than 100 μ were successfully produced by extrusion. The effects of the coupling agent (maleated PP), wood flour content (20%, 30%, and 40% weight), initial wood moisture, and blowing agent content on the cell structu…
The time correlation functions (TCFs) G(alphaalpha(t)[triple bond](Salpha(t)Salpha(0)) (alpha = x,y,z) of the electronic spin components of a complexed paramagnetic metal ion give information about the time fluctuations of its zero-field splitting (ZFS) Hamiltonian due to the random dynamics of the coordination polyhe…
Details of the chemical mechanism underlying the growth of colloidal semiconductor nanocrystals remain poorly understood. To provide insight into the subject, we have preformed a comprehensive study of the polar (0001) and (0001) and nonpolar (1120) wurtzite CdSe surfaces that are exposed during crystal growth using f…
Structural, thermomechanical, and dynamic properties of pure silica SiO2 are calculated with three different model potentials, namely, the potential suggested by van Beest, Kramer, and van Santen (BKS) [Phys. Rev. Lett. 64, 1955 (1990)], the fluctuating-charge potential with a Morse stretch term for the short-range in…
Model catalysts were prepared by deposition of size-selected Au(n) (n = 1-7) on rutile TiO2(110), and characterized by a combination of electron spectroscopy, ion scattering, temperature-programmed desorption, and pulse-dosing mass spectrometry. CO oxidation activity was found to vary strongly with deposited cluster s…
A series of hyperbranched azo-polymers have been synthesized by two-stage azo-coupling reactions, in which a hyperbranched precursor azo-polymer (HPAP) was prepared by step-growth polymerization of an AB 2 monomer through azo-coupling reaction and then was further modified by postpolymerization azo-coupling reaction a…
Fabrication of a nanosensor consisting exclusively of polymers with sensing performance superior to a microscale sensor is reported. The device is fabricated by a copolymer strategy combined with a lift-off process, which is capable of patterning a variety of conducting polymer species down to the nanometer scale (see…
Silver (Ag) doped and undoped ZnO films were grown on Si (100) substrates by the sol-gel process. Photoluminescence (PL) of two kinds of samples as a function of the excitation intensity has been measured, and PL intensities have been fitted by a power law. It is found that Ag doping increases the intensity of free em…
Scanning tunneling spectroscopic studies revealed the quantum-confinement effects in Ge nanocrystals formed with ultrahigh density (>1012cm−2) by Ge deposition on ultrathin Si oxide films. With decreasing crystal size, the conduction band maximum upshifted and the valence band minimum downshifted. The energy sh…
We report the synthesis of colloidal Ni(2+)-doped SnO(2) (Ni(2+):SnO(2)) nanocrystals and their characterization by electronic absorption, magnetic circular dichroism, X-ray absorption, magnetic susceptibility, scanning electron microscopy, and X-ray diffraction measurements. The Ni(2+) dopants are found to occupy pse…
A density functional theory investigation of the recently identified hydrogen storage reaction $\mathrm{Li}\mathrm{N}{\mathrm{H}}_{2}+\mathrm{Li}\mathrm{H}\ensuremath{\leftrightarrow}{\mathrm{Li}}_{2}\mathrm{N}\mathrm{H}+{\mathrm{H}}_{2}$ is described. The electronic structure and enthalpy of formation $\ensuremath{\D…
Abstract We report efficient electroluminescence in the near‐infrared from PbS–MEH‐PPV (poly(2‐methoxy‐5‐(2′‐ethylhexyloxy)‐1,4‐phenylenevinylene)) large‐area, solution‐cast nanocomposite devices. We employ multivariate optimization of the structural and materials components that govern the radiative, energy‐transfer,…
A series of novel hyperbranched multiarm copolyethers of PEHO- star -PPO with different molar ratios of PPO arms to PEHO cores ( R A/C ) were synthesized. NMR and SEC measurements confirm the molecular structure of PEHO- star -PPOs. Both glass transition temperature ( T g ) and decomposition temperature ( T d ) of PEH…
The effects of the Fock exchange on the geometries and electronic structures of TiO2 have been investigated by introducing a portion of Hartree-Fock (HF) exchange into the traditional density functional. Our results indicate that the functional with 13% HF exchange can correctly predict the band gap and the electronic…
Single crystals of flux-grown tetragonal GdFe4Al8 were characterized by thermodynamic, transport, and x-ray resonant magnetic scattering measurements. In addition to antiferromagnetic order at TN ~ 155 K, two low-temperature transitions at T1 ~ 21 K and T2 ~ 27 K were identified. The Fe moments order at TN with an inc…