Materials Literature
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Using an atomic force microscope we have created nanotube junctions such as buckles and crossings within individual single-wall metallic carbon nanotubes connected to metallic electrodes. The electronic transport properties of these manipulated structures show that they form electronic tunnel junctions. The conductanc…
Within the last 20 years, advances in characterization methods, particularly in the field of high–resolution electron microscopy, have made it possible to probe the surface and internal structure of sub–100 nm particles, or nanoparticles. Such studies have indicated conclusively that surface–energy considerations in m…
We present an experimental determination of the vibrational density of states in nanocrystalline Fe and Ni by inelastic neutron scattering. Nanocrystalline specimens with different grain size and microstrain have been prepared by ball milling and thermal annealing. The vibrational density of states has been extracted…
We implemented a coarse-graining procedure to construct mesoscopic models of complex molecules. The final aim is to obtain better results on properties depending on slow modes of the molecules. Therefore the number of particles considered in molecular dynamics simulations is reduced while conserving as many properties…
We present angular-dependent magnetotransport and magnetization measurements on $\ensuremath{\alpha}\ensuremath{-}(\mathrm{ET}{)}_{2}\mathrm{MHg}(\mathrm{SCN}{)}_{4}$ compounds at high magnetic fields and low temperatures. We find that the low-temperature ground state undergoes two subsequent field-induced density-wav…
An intermediate orthorhombic ferroelectric phase has been found in oriented crystals of (0.92)Pb(Zn1/3Nb2/3)O3–0.08PbTiO3 (PZN-PT 92/8). Investigations have been performed by electrically induced polarization and strain methods, and reciprocal phase space mapping. The lattice parameters of this intermediate ferroelect…
Graphyne is a hypothetical carbon allotrope with a layered structure. We calculated the optimized geometries and electronic structures of three-dimensional graphyne in some possible stacking arrangements from symmetry considerations. The optimized lattice constants and the binding energy of graphyne are given in compa…
We present numerical and analytical results describing the effect of hydrodynamic interactions on the dynamics of a short polymer chain in solution. A molecular dynamics algorithm for the polymer is coupled to a direct simulation Monte Carlo algorithm for the solvent. We give an explicit expression for the velocity au…
In this paper we report on the thermopower and electrical conductivities of ${\mathrm{Ti}}_{4}{\mathrm{AlN}}_{2.9}$ and ${\mathrm{Ti}}_{3}{\mathrm{Al}}_{1.1}{\mathrm{C}}_{1.8}$ in the 300--850 K temperature range. We also measured the room temperature Hall effect in ${\mathrm{Ti}}_{3}{\mathrm{SiC}}_{2},$ ${\mathrm{Ti}…
A modified elastic honeycomb model is presented to study elastic buckling of single-walled carbon nanotube ropes under high pressure. Simple formula is given for the critical pressure as a function of the Young's modulus and the thickness-to-radius ratio. For single-walled carbon nanotubes of diameters around 1.3 nm,…
In this paper we report the influence of the water vapor on the electrical resistance of a single-walled carbon nanotube mat (SWNTm). Our results show that the sample exhibits a crossover from decreasing to increasing conductance versus water concentration in the surrounding atmosphere. We suggest that the water molec…
Electron energy-loss spectra (ELS) have been obtained from polycrystalline Ag metal, AgO powder, and ${\mathrm{Ag}}_{2}\mathrm{O}$ powder using primary electron-beam energies ranging from 100 to 2000 eV. These samples were characterized using x-ray photoelectron spectroscopy (XPS) to determine the compositions and che…
Owing to their single atom-layer structure, actual bending stiffness of single-walled carbon nanotubes is much lower than that given by the elastic shell model if the commonly defined representative thickness is used. In this paper, it is proposed that the effective bending stiffness of single-walled nanotubes should…
Grazing-angle x-ray reflectivity (XRR) is described as an efficient, nondestructive, parameter-free means to measure the mass density of various types of amorphous carbon films down to the nanometer thickness range. It is shown how XRR can also detect layering if it is present in the films, in which case the reflectiv…
It is shown that a certain class of self-affine profiles of surface roughness may render any substrate with a non-zero microscopic contact angle non-wet, i.e. , give it a macroscopic contact angle close to 180 degrees. This is in some contrast to previous work and not only of potential applicational interest, but may…
Multiwall carbon nanotubes are produced by decomposition of acetylene at 600 °C on metal catalysts supported on NaY zeolite. The support and the metal are eliminated by dissolving them in aqueous hydrofluoric acid (HF). Two methods were used to eliminate the pyrolitic carbon: oxidation in air at 500 °C and oxidation b…
The dispersion process of Ag nanoparticles into vapor-deposited nylon 11 thin films caused by heat treatment has been investigated. In situ optical transmission and Fourier transform infrared (FT-IR) reflection absorption spectroscopy were used independently for characterizing the changes in the surface plasmon resona…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTSynthesis, Structure, and Magnetic Properties of a New Ternary Zintl Phase: Sr21Mn4Sb18Hyungrak Kim, Cathie L. Condron, Aaron P. Holm, and Susan M. KauzlarichView Author Information Department of Chemistry, University of California One Shields Avenue, Davis, California…
Two new aryl−ethynyl end-cap model compounds, N -phenyl-4-(1-naphthylethynyl)phthalimide ( 1 ) and N -phenyl-4-(2-naphthylethynyl)phthalimide ( 3 ), were synthesized and characterized. The single-crystal molecular structure of 1 reveals an alternating “head to tail” packing mode whereas the “heads and tails” of 2 are…
Chemical modification of Ar plasma-pretreated poly(tetrafluoroethylene) (PTFE) film by UV-induced graft copolymerization with glycidyl methacrylate (GMA), followed by oxidative graft copolymerization of aniline and reactive immobilization of polyaniline (PANI) chains have been carried out to render the PTFE surface co…