Materials Literature
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We have measured the plasmon dispersion of diamond along the high-symmetry directions using electron energy-loss spectroscopy in transmission. We found the plasmon dispersion to be considerably anisotropic. A comparison of the experimental results to ab initio calculations that take local-field effects into account de…
Microwave irradiation was applied to synthesize poly(ε-caprolactam-co-ε-caprolactone) directly from the anionic catalyzed ring opening of two cyclic monomers, ε-caprolactam and ε-caprolactone using a variable frequency microwave furnace, programmed to a set temperature and controlled by a pulsed power on–off system. D…
This article discusses a new chemical route to prepare maleic anhydride (MA) grafted polyethylene and polypropylene polymers with controlled molecular structure, that is, MA grafted content and polymer molecular weight and composition distributions. The chemistry involves a free radical graft reaction of maleic anhydr…
Nanostructural characterization of amorphous diamondlike carbon $(a\ensuremath{-}\mathrm{C})$ films grown on silicon using pulsed-laser deposition (PLD) is correlated to both growth energetics and film thickness. Raman spectroscopy and x-ray reflectivity probe both the topological nature of three- and four-fold coordi…
The effects of Na and Ba atoms doped into silicon clathrate compounds, ${\mathrm{Na}}_{8}{\mathrm{Si}}_{46}$ and ${\mathrm{Ba}}_{8}{\mathrm{Si}}_{46},$ on their energy-band modification have been studied. Both Na and Ba atoms occupy center sites of dodecahedral $({\mathrm{Si}}_{20})$ and tetrakaidecahedral cages $({\m…
In this study, the structural factors controlling the yield in isotactic polypropylene materials were theoretically investigated. To describe the yielding behavior of spherulitic polypropylenes, we introduced a new structural unit, lamellar clusters, which are several stacked lamellae bound by tie molecules. It was sh…
The charge transport on a single conducting polymer chain is investigated. The dynamics of polarons and bipolarons is numerically studied using the Su-Schrieffer-Heeger model combined with the Pariser-Parr-Pople model extended to include an external electric field and a Brazovskii-Kirova symmetry breaking interaction.…
An investigation was conducted on the introduction of amino groups to the surface of activated carbon and the adsorption characteristics of the aminated surface. The organic chemical reactions allowed us to introduce amino groups to the surface of activated carbon without affecting the physical structure of the adsorb…
We have performed $\mathrm{ab}$ $\mathrm{initio}$ pseudopotential electronic structure calculations for various edge geometries of the $(n,n)$ single-wall nanotube with or without applied fields. Among the systems studied, the one with a zigzag edge exposed by a slant cut is found to be the most favorable for emission…
Lead zirconate titanate (PZT) thin films with a Zr/Ti ratio of 52/48 were deposited on platinized silicon substrates by a sol-gel method and crystallized with preferred (111) or (100) orientation. Both the piezoelectric properties (d33) and the field-induced strains of the films with different thickness and preferred…
We present a tight-binding theory to analyze the motion of electrons between carbon nanotubes bundled into a carbon nanotube rope. The theory is developed starting from a description of propagating Bloch waves on ideal tubes, and the effects of intertube motion are treated perturbatively on this basis. Expressions for…
We report on a calibration procedure based on third-harmonic generation, which yields absolute values for ${\ensuremath{\chi}}^{(3)}.$ By calibrating the nonlinear susceptibility ${\ensuremath{\chi}}^{(3)}$ of fused silica against the established, quantum chemically calculated second-order hyperpolarizabilities \ensur…
${\mathrm{Eu}}^{2+}$-doped ZnS nanoparticles with an average size of around 3 nm were prepared, and an emission band around 530 nm was observed. By heating in air at 150 \ifmmode^\circ\else\textdegree\fi{}C, this emission decreased, while the typical sharp line emission of ${\mathrm{Eu}}^{3+}$ increased. This suggests…
We report the effects of potassium doping on the conductance of individual semiconducting single-walled carbon nanotube ropes. We are able to control the level of doping by reversibly intercalating and de-intercalating potassium. Potassium doping changes the carriers in the ropes from holes to electrons. Typical value…
We report a photoluminescence study of silicon nanoclusters produced by laser ablation. It was found that by varying the preparation parameters it was possible to change the mean cluster size in the range 1–5 nm. Within this size variation, the photoluminescence band shifts in a wide spectral region from near ultravio…
Photoluminescence excitation (PLE) spectra, measured at varying temperatures and for different luminescent energies, are applied systematically to the study of defects in $\mathrm{I}a,$ $\mathrm{I}b,$ $\mathrm{II}b,$ and chemical-vapor-deposited (CVD) diamond. It is shown that the green luminescent band in CVD diamond…
We present a detailed quantitative comparison of double-exchange models to experimental data on the colossal magnetoresistance manganese perovskites. Our results settle a controversy by showing that physics beyond double-exchange is important even in ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_{3},$ which ha…
We introduce a continuous damage fiber bundle model that gives rise to macroscopic plasticity and compare its behavior with that of dry fiber bundles. Several interesting constitutive behaviors are found in this model depending on the value of the damage parameter and on the form of the disorder distribution. In addit…
Off-lattice grand canonical Monte Carlo simulations of the clean diamond (111) surface, based on the effective many-body Brenner potential, yield the $(2\ifmmode\times\else\texttimes\fi{}1)$ Pandey reconstruction in agreement with ab initio calculations and predict the existence of metastable states, very near in ener…
A thermodynamic theory of ferroelectric thin film multilayers is developed. The free energy function is written down using a multilayer model in which c-domain layers of one ferroelectric material alternate with a-domain layers of a second ferroelectric material. We assume that the interfaces are perfectly sharp and t…