Materials Literature
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Nanocrystalline columnar-structured diamond films with column diameters less than 100 nm and thicknesses in the range of 1–5 μm were grown on silicon substrates by chemical vapor deposition (CVD) in a microwave plasma reactor with purified methane and hydrogen used as the reactants. Uniform conformal nucleation densit…
Thick films of single wall carbon nanotubes (SWNT) exhibiting in-plane preferred orientation have been produced by filter deposition from suspension in strong magnetic fields. We characterize the field-induced alignment with x-ray fiber diagrams and polarized Raman scattering, using a model which includes a completely…
We report on the photoluminescent characteristics of ZnO single crystal nanorods grown by catalyst-free metalorganic vapor phase epitaxy. From photoluminescence (PL) spectra of the nanorods at 10 K, several PL peaks were observed at 3.376, 3.364, 3.360, and 3.359 eV. The PL peak at 3.376 eV is attributed to a free exc…
The oxidation of aqueous solutions of glycerol is described and discussed for Pd, Pt and Au nanoparticles supported on graphite and activated carbon. The oxidation in a batch reactor at 60 °C and 1 bar pressure using air as oxidant was initially investigated. Under these conditions, supported Pd and Pt catalysts give…
Carbon nanotubes (CNTs) deposited by plasma-enhanced chemical vapor deposition on Si3N4/Si substrates have been investigated as resistive gas sensors for NO2. Upon exposure to NO2, the electrical resistance of the CNTs was found to decrease. The maximum variation of resistance to NO2 was found at an operating temperat…
The filament structures of the self-polymers of RecA proteins from Escherichia coli and Pseudomonas aeruginosa, their complexes with ATPgammaS, phage M13 single-stranded DNA (ssDNA) and the tertiary complexes RecA::ATPgammaS::ssDNA were compared by small angle neutron scattering. A model was developed that allowed for…
The selective light reflection and turbidimetric property of concentrated aqueous solutions of (hydroxypropyl)cellulose (HPC), originating from their cholesteric mesophase structure and LCST-type phase behavior, respectively, are much affected by coexistence of inorganic salts therein. This is ascribed to a strong dep…
The oxovanadium(IV) sandwich-type POM catalyzes the chemo-, regio-, and stereoselective epoxidation of allylic alcohols by chiral hydroperoxides with very high catalytic efficiency (up to 42 000 TON), a potentially valuable oxidation for the development of sustainable processes. By using the sterically demanding, TADD…
Low-temperature ultrahigh-vacuum scanning tunneling microscopy was employed to analyze the electronic behavior of Au 55 clusters stabilized by [P(C 6 H 5 ) 3 ] 12 Cl 6 ligands. At 7 K, the actual arrangement of the C 6 H 5 rings of the ligand molecules could be imaged. Spectroscopic data reveal discrete energy levels…
Reactions between triphenyl bismuth, salicylic acid, and niobium or tantalum ethoxide have been explored. Four new coordination complexes incorporating bismuth and the group 5 metals niobium or tantalum have been synthesized and characterized spectroscopically, by elemental analysis, and by single crystal X-ray diffra…
Guest−host interactions of poly(amidoamine) dendrimers and porous surfaces, such as homoporous silica of different pore sizes, activated alumina (acidic, neutral, basic), and MCM-41 zeolite (Si/Al=30), were investigated by electron paramagnetic resonance (EPR) spectroscopy. Two generations of dendrimers were selected,…
This paper reports a new mechanism for the formation of clay intercalates containing poly(ethylene oxide) (PEO). This mechanism permits formation of a two-dimensional PEO crystal phase. Under acidic conditions, polymer adsorption occurs through an ion-exchange process that is mediated by oxonium cation formation. A si…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTElectrostatic Interactions between Shortened Multiwall Carbon Nanotubes and PolyelectrolytesBumsu Kim, Hyun Park, and Wolfgang M. SigmundView Author Information Department of Materials Science & Engineering, University of Florida, 225 Rhines Hall, P.O. Box 116400, Gainesville,…
The excited-state dynamics of two conjugated bis[(porphinato)zinc(II)] (bis[PZn]) species, bis[(5,5'-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethyne (DD) and [(5,-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5',-15'-ethynyl-10',20'-bis(heptafluoropropyl)porphinato…
The layer-by-layer (LBL) deposition technique has been applied to the design of polymer electrolyte films appropriate for electrochemical applications such as sensors and electrochromic cells. In this work, we describe the properties of three LBL polymer electrolyte systems assembled from cationic layers of linear pol…
Single-walled carbon nanotubes (SWNTs) prepared by pulsed laser vaporization, dispersed, and surfactant-stabilized in near-infrared transparent D 2 O show weak photoluminescence (PL) from ∼1300 up to >1750 nm corresponding to the lowest electronic interband transitions of semiconducting tubes. The characteristic featu…
This paper deals with the modifications of the chemical surface functionalities and the textural changes of a glassy carbon produced by three oxidizing agents: ozone, hydrogen peroxide, and oxygen plasma. The chemical surface changes are evaluated by using Fourier transform infrared spectroscopy, temperature-programme…
The electronic structure and chemical bonding of B 6 - and B 6 were investigated using anion photoelectron spectroscopy and ab initio calculation. Vibrationally resolved photoelectron spectra were obtained for B 6 - and were compared to calculations performed at various levels of theory. Extensive searches were carrie…
Adsorption equilibria of seven chlorinated volatile organic compounds on mesoporous silicate MCM-48 were obtained using a gravimetric technique. For comparison purposes, three organic sorbents (activated carbon, activated carbon fiber and nonionic polymer resin, SP850) and three inorganic sorbernts (DAY zeolite, mesop…
A tilted smectic phase of a new achiral banana-shaped mesogen is presented. It possesses liquidlike order within the layers and appears with a fan-shaped texture. At sufficiently high electric fields, this texture can be transformed into a texture that displays a complete extinction between crossed polarizers and it f…