Materials Literature
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Mass production of quasi-one-dimensional gallium oxide nanobelts is accomplished through graphite-thermal reduction of a mixture of gallium oxide powders and SnO2 nanopowders under controlled experimental conditions. Sn nanoparticles are located at or close to the tips of the nanobelts and served as the catalyst for t…
Single-crystal nanowires of zinc oxide were prepared by a novel self-seeded vapour–liquid–solid (VLS) growth method using ultrasonic spray-assisted chemical vapour deposition, in which liquid Zn droplets were used as ‘catalysts’. In this approach, a nanocrystalline seed layer was first deposited, by direct decompositi…
Undoped and Ce-doped Ba 0.5 Sr 0.5 TiO 3 (BST) thin films were prepared by pulsed-laser deposition onto a Nb-doped SrTiO 3 (STON) substrate. The Ce concentration, ranging from 0.5 to 1.0 at.%, was found to have a strong influence on the electric properties of films at room temperature. We find that, with a positively…
The orbital excitations of a series of transition-metal compounds are studied by means of optical spectroscopy. Our aim was to identify signatures of collective orbital excitations by comparison with experimental and theoretical results for predominantly local crystal-field excitations. To this end, we have studied Ti…
Molecular simulation techniques are used to find the basal spacing of organoclay on the basis of the energy minimum, using the canonical NVT ensemble. Then, the interlayer structure and mobility of alkyl chains are explored based on the interlayer atomic density profiles. Besides the basic lateral-monolayer arrangemen…
This work investigates the evolution of micro-Raman spectra of a [001]-oriented 0.67Pb(Mg1∕3Nb2∕3)O3–0.33PbTiO3 single crystal in the temperature range from −120 to 200 °C. For a poled sample, the T1u mode splits into an E mode (remaining at 51cm−1) and a new A1 mode (shifting to 95cm−1 at −120°C) at the tetragonal to…
The field emission characteristics of multiwalled carbon nanotubes at various temperatures are studied. It is found that the turn-on field and emission current at a given applied electric field are dependent on the ambient temperature of the nanotube. This dependence is believed to be due to the change in the work fun…
We present a floating-potential dielectrophoresis method used for the first time to achieve controlled alignment of an individual semiconducting or metallic single-walled carbon nanotube (SWCNT) between two electrical contacts with high repeatability. This result is significantly different from previous reports, in wh…
The fracture behavior of semicrystalline polymers is controlled by the micromechanisms associated with formation and breakdown of a plastic deformation region at notches, cracks, or other stress raising defects. In this context, it is widely acknowledged that material toughness may arise from the volume of the plastic…
Conditions for inception of dc corona discharges in air near spherical and cylindrical anodes are considered. The parameter K (ionization integral) in the standard discharge inception criterion is evaluated for a wide range of electrode radii and air densities.
The role of Ti in improving the thermodynamics of hydrogen desorption in crystalline sodium alanate (NaAlH4) has been investigated by using the density functional theory. The total energy calculations reveal that Ti prefers to occupy the Na site over that of the Al site when the atomic energies are used as the referen…
Sonochemical reaction between (NH4)6Mo7O24 and CH3COSH in aqueous solution leads to the formation of hollow MoS2 microspheres, replicating the shape of cavitation bubbles. The walls of these hollow spheres consist of short and low-stacked MoS2 fringes providing to the material very high intrinsic catalytic activity in…
Pump and probe experiments on Er3+ ions coupled to Si nanoclusters have been performed in rib-loaded waveguides to investigate optical amplification at 1.5μm. Rib-loaded waveguides were obtained by photolithographic and reactive ion etching of Er-doped silica layers containing Si nanoclusters grown by reactive sputter…
Electronic devices made from carbon nanotubes (CNTs) can be greatly affected by substrate charges, which, for instance, induce strong hysteresis in CNT field effect transistors. In this work, electrostatic force microscopy (EFM) is employed to investigate single-walled nanotubes grown by chemical vapor deposition on S…
Co nanoparticles have been assembled in situ on a template of double-stranded deoxyribonucleic acid (DNA) to form magnetic nanowires. DNA was immobilized on freshly cleaved mica or silanized glass and oriented by molecular combing. Pd(II) ions bound to DNA were reduced to zero-valence nanoclusters, which selectively c…
Abstract To enable the use of GaAs‐based devices as chemical sensors, their surfaces must be chemically modified. Reproducible adsorption of molecules in the liquid phase on the GaAs surfaces requires controlled etching procedures. Several analytical methods were applied, including Fourier transform infrared spectrosc…
We investigate how the phase diagram of a repulsive soft-core attractive potential, with a liquid-liquid phase transition in addition to the standard gas-liquid phase transition, changes by varying the parameters of the potential. We extend our previous work on short soft-core ranges to the case of large soft-core ran…
Using density functional theory, we have theoretically studied dioxin binding on a graphene sheet or carbon nanotubes (CNT), finding that they can be effective adsorbents for dioxin in the presence of calcium atoms. This is due to a cooperative formation of sandwich complexes of graphene sheet or (5,5) CNT through the…
Recent combined experimental and theoretical studies (Beck et al., Phys. Rev. Lett. 2004, 93, 036104) have provided evidence for Ti=O double-bonded titanyl groups on the reconstructed rutile TiO(2)(011)-(2 x 1) surface. The adsorption of water on the same surface is now investigated to further probe the properties of…
Abstract Phase equilibrium studies of the Bi–Zn–Nb–O system show that pyrochlore does not form at chemical compositions predicted by the traditional formula for this crystal structure, A 2 B 2 O 6 O', where A denotes large (8‐coordinated, e.g. Bi 3+ ) and B small (6‐coordinated, e.g. Zn 2+ , Nb 5+ ) cation sites. Inst…