Materials Literature
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Dowex 50Wx8-catalyzed reactions occurring in systems containing acetic acid, benzyl alcohol, benzyl acetate, and water were studied over a range of catalyst loadings, temperatures, and feed compositions. The initial esterification rate is found to depend on these reaction conditions. The presence of water rather than…
X-ray absorption fine structure spectroscopy has been used to study the chemical and structural properties of self-forming diffusion barrier layers from Cu-8 at. % Mn alloy films on porous low-k and thermally grown SiO2 dielectrics. For the porous low-k/Cu(Mn) system, we provide evidence that the interface is composed…
We carried out temperature-dependent photoluminescence measurements to investigate the influence of surface roughness on the phonon-assisted emission of the surface-tailored ZnO nanowires (NWs). For the rough ZnO NWs, the observation of strong defect emission with vibration peaks by the exciton-phonon coupling reflect…
Single crystals of multiferroic cobalt chromite Co(Cr2−xCox)O4 have been grown via several methods to have different Co3+ doping levels (x=0.0, 0.14, and 0.18). Under magnetic fields, all the crystals display electric polarization reversal below their spiral spin ordering temperatures. We find that both saturated elec…
Amphiphilic triblock copolycarbonates poly(glycerol carbonate- b -DTC- b -glycerol carbonate) with poly(glycerol carbonate) chains as the hydrophilic blocks were designed and synthesized. In the first step, the PDTC diol macroinitiators were synthesized via bulk polymerization of DTC with 1,6-hexanediol as an initiato…
In situ Au3+--> reaction and dispersion of the resulting gold in the form of nanoparticles (NPs) in a reactive polymer medium, such as poly(vinyl alcohol) (PVA) molecules in hot water, are explored to devise a composite Au-PVA structure of self-standing films. The Au-NPs (0-2 wt%) tailor a violet to purple to a yellow…
Ferroelectric Ising chain magnet ${\text{Ca}}_{3}{\text{Co}}_{2\ensuremath{-}x}{\text{Mn}}_{x}{\text{O}}_{6}$ $(x\ensuremath{\simeq}0.96)$ was studied in magnetic fields of up to 33 T. Magnetization and neutron-scattering measurements reveal successive metamagnetic transitions from the zero-field $\ensuremath{\uparrow…
According to the characteristics of the cyclohexane oxidation reaction a series of bifunctionalized hexagonal mesoporous silicas, CoPh-HMS, were designed and successfully synthesized by a one-step co-condensation route. The results of small-angle XRD, TEM, and N 2 adsorption−desorption measurements showed that the res…
The focus of this paper is the hotdog-fold thioesterase THEM2 from human (hTHEM2; Swiss-Prot entry Q9NPJ3 ). In an earlier communication (Cheng, Z., Song, F., Shan, X., Wei, Z., Wang, Y., Dunaway-Mariano, D., and Gong, W. (2006) Crystal structure of human thioesterase superfamily member 2, Biochem. Biophys. Res. Commu…
Electromigration in copper (Cu) nanowires deposited by electron beam evaporation has been investigated using both resistance measurement and the in situ scanning electron microscopy technique. During electromigration, voids formed at the cathode end while hillocks (or extrusions) grew close to the anode end. The failu…
The x-ray absorption near edge structure spectroscopy and first-principles calculations were combined to study the local and electronic structures of rutile Co:TiO2 thin film with room-temperature ferromagnetism. It was revealed that the CoTi2+ substituting the Ti site forms CoTi2+-VO complex with the O vacancy genera…
Self-assembled conducting, paramagnetic polyaniline nanotubes have been synthesized by the oxidative polymerization of aniline with ammonium peroxydisulfate in aqueous medium in the presence of zeolite HZSM-5, without added acid. The influence of initial zeolite/aniline weight ratio on the conductivity, molecular and…
Solution-phase pyridine treatment displaced oleic acid capping ligands from the surface of PbSe nanocrystals. During ligand displacement the nanostructure morphology dramatically changed from well-stabilized, individual nanocrystals to form crystallographically connected nanocrystal networks. The network morphology wa…
Organic−inorganic nanocomposites consisting of electroactive conjugated polymer, poly(3-hexylthiophene) (P3HT), intimately tethered on the surface of semiconductor CdSe quantum dot (i.e., P3HT−CdSe nanocomposites) at the air/water interface formed via Langmuir isotherms were explored for the first time. The P3HT−CdSe…
In this work, the authors showed that the directivity and efficiency of an electromagnetic (EM) emission could be greatly improved by embedding the source in an anisotropic matrix with one component of the physical parameters near zero. This unique property led us to design a slab-shaped rectangular antenna that could…
To enhance efficiencies of quantum dot CdSe/TiO(2) based solar cells, understanding of the space charge at the CdSe/TiO(2) interface is crucial. In this paper, the presence of a shallow acceptor in the CdSe quantum dots is found by means of a detailed impedance and Mott-Schottky (C(-2)-phi) study. Furthermore, it is c…
The Eu3+ and Tb3+ doped glass ceramics containing tetragonal LiYbF4 nanocrystals were prepared. The Stark splitting emission, the low electric dipole D50→F72 transition, and the long lifetime of Eu3+ evidenced the partition of rare earth into LiYbF4. For Tb3+ doped glass ceramic, intense ultraviolet emission of Tb3+:…
Samples of polydisperse gold nanoclusters (AuNCs) protected with monolayers of N-acetyl-L-cysteine (NAC) have been chromatographically separated by a C18 column (4.6 mm x 250 mm) using a gradient elution program with a mobile phase of methanol (MeOH)/water containing tetrabutylammonium fluoride (Bu(4)N(+)F(-)) and sod…
We report on first-principles density functional calculations about the adsorption of water molecules on the nonpolar ZnO(101̅0) surface, as a function of the molecular coverage. Our results allow us to unravel the reaction mechanisms that drive the partial dissociation of water molecules at saturation coverage: Altho…
The structures of the molecules methylamine-borane, MeH(2)N.BH(3), and dimethylamine-borane, Me(2)HN.BH(3), have been investigated by gas-phase electron diffraction (GED) and quantum chemical calculations. The crystal structures have also been determined for methylamine-, dimethylamine-, and trimethylamine-borane, Me(…