Light scattering lineshape in opaque materials

The wavevector distribution excited by light scattering in opaque materials is calculated and compared to recently observed asymmetrical Brillouin lineshapes.     

Low temperature thermal conductivity of graphite-FeCl3 intercalation compounds

The low-temperature variation of the in-plane thermal conductivity of graphite- FeCl₃ intercalation compounds is reported. Around room temperature, though holes are participating, there is an important lattice contribution, but much smaller than in pristine graphite. The electronic contribution dominates in the liquid helium range. These preliminary results suggest lattice thermal conductivity measurements as a new tool to investigate defects introduced by intercalation.     

Chemisorbed phases of H2O on TiO2 and SrTiO3

Ultraviolet photoemission spectroscopy in ultrahigh vacuum has been used to study the interaction of H₂O with argon-ion-bombarded and annealed TiO₂(110) and SrTiO₃ (100) surfaces. At low exposure, evidence is found for the presence of the OH free radical on both bombarded and annealed TiO₂. At high exposure, a spectrum of slightly perturbed adsorbed H₂O is observed, with the a₁ molecular orbital shifted 0.5–1 eV toward tighter binding. This suggests that H₂O binds to the surface of TiO₂ via its a₁, in-plane O lone-pair orbital. No evidence is found for OH on the surface of SrTiO₃. The spectrum of H₂O adsorbed on bombarded SrTiO₃ shows both the a₁ and b₂ molecular orbitals shifted 0.4 toward tighter binding, indicating a more complicated bonding to the surface. For SrTiO₃ that has been bombarded and then annealed, the spectrum of adsorbed H₂O shows no significant bonding effects.     

PRESSURE-VELOCITY EQUILIBRIUM HYDRODYNAMIC MODELS

This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.     

Microstructure of Milled Mesophase Pitch-Based Carbon Fibers as an Anode Material for Li-ion Batteries

Abstract

The microstructure of milled mesophase pitch-based carbon fibers (mMPCFs) that have been developed as an anode material for Li ion batteries have been studied as a function of heat treatment temperature (HTT), by SEM, X-ray diffraction, and Raman spectroscopy. And the results obtained are compared with those by X-ray diffraction (XRD) and SEM observations, for the characterization of specific structural features of mMPCFs as a promising anode material.     

Transport properties of copper-doped carbon aerogels

The magnetic susceptibility, conductivity, magnetoresistance (MR) and Hall effect of copper-doped carbon aerogels are measured and compared with corresponding results from the original carbon aerogels. The experimental results indicate that the temperature-dependent magnetic susceptibility of the copper-doped and of the original carbon aerogels is well fit by a Curie function at low temperatures. The copper-doped carbon aerogels show a higher susceptibility and spin concentration than the original carbon aerogel. After doping by copper, the materials exhibit a more linear current-voltage curve than the original carbon aerogel under the same measurement conditions. The electrical resistance of the copper-doped carbon aerogels is strikingly lower than that of the original carbon aerogels, and decreases with increasing copper content in the samples. The temperature-dependent resistivity ρ(T) of all of the copper-doped and original carbon aerogels can be fitted by an exp(T^−1/2) dependence for T<100 K. The copper-doped and pristine carbon aerogels follow a quadratic MR behavior Δρ/ρ=AB² in the magnetic field range B investigated (up to 5 T), except at very low temperatures (T<4 K).     

Transparent and Conductive Polyethylene Oxide Film by the Introduction of Individualized Single‐Walled Carbon Nanotubes

It is demonstrated that an optically transparent and electrically conductive polyethylene oxide (PEO) film is fabricated by the introduction of individualized single‐walled carbon nanotubes (SWNTs). The incorporated SWNTs in the PEO film sustain their intrinsic electronic and optical properties and, in addition, the intrinsic properties of the polymer matrix are retained. The individualized SWNTs with smaller diameter provide high transmittance as well as good electrical conductivity in PEO films.