Materials Literature
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We report first-principles electronic-structure calculations using local density approximation in density functional theory for hexagonally bonded hetero-sheets ${\mathrm{BNC}}_{x}$ consisting of graphite and boron-nitride strips. We find a class of electron states that are localized at borders of the heterosheet. Cal…
Graphite nanoparticles were prepared by the heat treatment of diamond nanoparticles in the range 900--1600 \ifmmode^\circ\else\textdegree\fi{}C. X-ray diffraction, transmission electron microscopy (TEM) and Raman scattering studies indicate that the onset temperature of the diamond-graphite transition is around 1200 \…
In this study we present the coarse-graining of one polymer chain in a melt to a single dimer. By using the projector operator formalism we derive the equation of motions for the dimer. The different forces that occur in this equation of motion are calculated from molecular dynamics simulations of the microscopic mode…
Ralstonia eutropha H16 degraded (mobilized) previously accumulated poly(3-hydroxybutyrate) (PHB) in the absence of an exogenous carbon source and used the degradation products for growth and survival. Isolated native PHB granules of mobilized R. eutropha cells released 3-hydroxybutyrate (3HB) at a threefold higher rat…
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…