Materials Literature
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We report measurements of the thermoelectric power (TEP) S and electrical resistance R of thin films of tangled ropes of single-walled carbon nanotubes. Experiments at 300 K under applied force normal to the plane of the film revealed a $\ensuremath{\sim}10--20 %$ decrease in the four-probe resistance, indicating that…
A systematic Raman study of boron carbonitride (BCN) nanotubes, synthesized by bias-assisted hot filament chemical vapor deposition, is reported. Raman spectra up to the fourth order are observed from the BCN nanotubes. Comparing with pure carbon nanotubes, the Raman bands in BCN nanotubes are broadened and the relati…
La-substituted bismuth titanate [Bi4−xLaxTi3O12(BLT)] films were synthesized using pulsed-laser deposition and ferroelectric fatigue phenomenon was investigated. The internal strain present in the films, which was analyzed through the evaluation of the x-ray diffraction peak, was partially responsible for the fatigue…
Hexagonal polycrystalline boron-nitride (BN) films are synthesized on Si substrates by plasma-assisted chemical-vapor deposition. In the case of BN films thicker than 20 nm, the turn-on electric field of the electron emission decreases with increasing surface roughness. On the other hand, in the case of BN film as thi…
Nematic liquid crystal materials are rod-like molecules that align in a locally common direction called the director. This gives rise to anisotropic properties that are used in electro-optical devices such as displays, which usually consist of a sandwich of material between two substrates. The behavior of the director…
Luminescent Y3Al5O12: Ce3+ [yttrium aluminum garnet (YAG):Ce3+] nanoceramics (5–50 nm) have been prepared through a facile sol-gel pyrolysis route. A blueshift of about 720 cm−1 in the reflectance spectra near the absorption edge can be observed for YAG:Ce3+ nanoparticles (having an average particle size around 5 nm)…
Solid electrolytes with disordered structures, both crystalline and glassy, as well as supercooled ionic melts, exhibit surprisingly similar features in their conductivity spectra, σ(ν). This finding suggests that the dynamics of the mobile ions in the different systems should be governed by similar rules. Examples ar…
BaTiO 3 ( BTO )/ SrTiO 3 ( STO ) artificial superlattices have been made on MgO (100) substrates. The periodicity of the BTO/STO layers in the superlattice was varied from one-unit cell to 125-unit cell thickness. The dielectric constant and its nonlinearity (or voltage tunability) showed similar behavior as the perio…
We propose an analytical interatomic potential for modeling platinum, carbon, and the platinum-carbon interaction using a single functional form. The ansatz chosen for this potential makes use of the fact that chemical bonding in both covalent systems and d-transition metals can be described in terms of the Pauling bo…
Monodispersed ZnS and Eu3+-doped ZnS nanocrystals have been prepared through the co-precipitation reaction of inorganic precursors ZnCl2, EuCl3, and Na2S in a water/methanol binary solution. The mean particle sizes are about 3–5 nm. The structures of the as-prepared ZnS nanoparticles are cubic (zinc blende) as demonst…
Both ``phason'' elastic constants have been measured from Monte Carlo simulations of a random-tiling icosahedral quasicrystal model with a Hamiltonian. The low-temperature limit approximates the ``canonical-cell'' tiling used to describe several real quasicrystals. The elastic constant K2 changes sign from positive to…
Using density-functional theory (DFT) we investigate the incorporation of oxygen directly below the Rh(111) surface. We show that oxygen incorporation will only commence after nearly completion of a dense O adlayer (θ_tot = 1.0 monolayer) with O in the fcc on-surface sites. The experimentally suggested octahedral sub-…
The equilibrium structure and exchange constants of ${\mathrm{CaMnO}}_{3}$ and ${\mathrm{LaMnO}}_{3}$ have been investigated using total-energy unrestricted Hartree-Fock (UHF) and localized orbital configuration interaction (CI) calculations on bulk compounds and ${\mathrm{Mn}}_{2}{\mathrm{O}}_{11}^{14\ensuremath{-}}$…
The calculation of the polarization in ferroelectric thin films is performed using an analytical solution of the Euler-Lagrange differential equation with boundary conditions with different extrapolation lengths of positive sign on the surfaces. The depolarization field effect is taken into account in the model for a…
We report the first ab initio density-functional study of the strain field and Peierls stress of isolated <111> screw dislocations in bcc Mo and Ta. The local dislocation strain field is self-consistently coupled to the long-range elastic field using a flexible boundary condition method. This reduces the mesoscopic at…
Single-bubble sonoluminescence occurs when an acoustically trapped and periodically driven gas bubble collapses so strongly that the energy focusing at collapse leads to light emission. Detailed experiments have demonstrated the unique properties of this system: the spectrum of the emitted light tends to peak in the u…
The crystal structure of the novel title diphosphate, Li(2)BaP(2)O(7), exists with a three-dimensional lattice composed of BaO(9) polyhedra linked to corner- and edge-sharing P(2)O(7) diphosphate groups, forming layers parallel to the (010) plane, the layers being linked by P[bond]O[bond]Ba bridges. Tunnels thus creat…
Thermal, rheological, and fiber spinning behavior of poly(ethylene terephthalate- co -4,4‘-bibenzoate) random copolymers containing 5−65 mol % bibenzoate (BB) units have been studied. Copolymer randomness was determined by 13 C solution NMR. Copolymers with >40 mol % BB units spin like thermotropic liquid crystals and…
The interaction between two proteins, Mefp-1 and Mefp-2, from the byssal plaque of the blue mussel, Mytilus edulis, was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D) technique. The challenge in using a surface-sensitive technique to investigate the interaction between two strongl…
Facile formation of organometallic dendrons utilizing steric control is demonstrated, affording rapid access to nanometer-sized π-delocalized quadrupolar and octopolar complexes.