Materials Literature
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Nanostructured hybrid materials were prepared by sol–gel hydrolysis–polycondensation of tetrakis(4-trisisopropoxysilylphenyl)germane PGe and tetrakis(4-trisisopropoxysilylphenyl) tin PSn which present a tetrahedral germanium or tin central atom. Both precursors presented twelve directions for solid formation oriented…
Pd is deposited onto a reconstructed ${\mathrm{SrTiO}}_{3}(001)$ substrate in an ultrahigh vacuum environment. Elevated substrate temperature during or following deposition causes epitaxial Pd nanocrystals to form. The nanocrystal shape and size distributions are analyzed by scanning tunneling microscopy. We find that…
Abstract X‐ray diffraction and differential scanning calorimeter (DSC) methods have been used to investigate the crystallization behavior and crystalline structure of hexamethylenediamine (HMDA)‐modified maleic‐anhydride‐grafted polypropylene/clay (PP‐ g ‐MA/clay) nanocomposites. These nanocomposites have been prepare…
The dynamics of the second-order nonlinearity induced in a thermally poled Infrasil silica glass is experimentally and theoretically studied. 200 mum and 500 mum-thick samples have been poled for different durations varying from 1 minute to 100 minutes. After the poling process, the magnitude and the spatial distribut…
Abstract The crystallization kinetics of biodegradable poly(butylene succinate‐ co ‐adipate) (PBS/A) copolyester was investigated by using differential scanning calorimetry (DSC) and polarized optical microscopy (POM), respectively. The Avrami and Ozawa equations were used to analyze the isothermal and nonisothermal c…
First-principles calculations based on density functional theory are carried out to understand the mechanisms responsible for hydrogen desorption from Ti-doped sodium-alanate $(\mathrm{Na}\mathrm{Al}{\mathrm{H}}_{4})$. While the energy needed to remove a hydrogen atom from $\mathrm{Na}\mathrm{Al}{\mathrm{H}}_{4}$ with…
Abstract Based on the fiber diffraction data from native collagen, Rich and Crick proposed the 10/3‐helical model with a 28.6 Å axial repeat in 1955 (Rich A.; Crick, F. H. C. Nature (Lond) 1955, 176, 915–916 ). We obtained the 7/2‐helical structure with a 20 Å axial repeat from the single crystal analysis of (Pro–Pro–…
The IR-active vibrational modes of single-walled carbon nanotubes have been observed by optical transmission through thin films of bundled nanotubes. Because IR-active chemical functional groups, e.g., -COOH, -OH, might be attached to the tube walls and contribute additional spectral features, we have also studied the…
We derive the multi-field, micropolar-type continuum theory for the two-dimensional model of crystal having finite-size particles. Continuum theories are usually valid for waves with wavelength much larger than the size of primitive cell of crystal. By comparison of the dispersion relations, it is demonstrated that in…
A multilayer perovskite thin film resistive memory device has been developed comprised of: a Pr0.7Ca0.3MnO3 (PCMO) perovskite oxide epitaxial layer on a YBCO bottom thin film electrode; a thin yttria stabilized zirconia (YSZ) buffer layer grown on the PCMO layer, and a gold thin film top electrode. The multi-layer thi…
Nonlocal one-dimensional motions of a topological defect are induced by electron tunneling through the dangling-bond states on the clean Ge(001) surface using scanning tunneling microscopy below 80 K. The direction of the motion depends both on the energy of the carriers in the surface state and on the distance betwee…
In order to estimate roughness exponents of interface growth models, we propose the calculation of effective exponents from the roughness fluctuation (sigma) in the steady state. We compare the finite-size behavior of these exponents and the ones calculated from the average roughness for two models in the 2+1-dimensio…
A new model of a symmetric two-terminal non-volatile RRAM device based on Perovskite oxide thin film materials, specifically Pr1-xCaxMnO3 (PCMO), is proposed and analyzed. The model consists of two identical half-parts, which are completely characterized by the same resistance verses pulse voltage hysteresis loop, con…
We have investigated STM images of the (110) cross-sectional surface of Mn-doped GaAs using first principles total-energy pseudopotential calculations. We focus on configurations with Mn interstitial in the uppermost surface layers. In particular, we have found that Mn impurities, surrounded by Ga or As atoms, introdu…
We propose a time-dependent photonic structure, in which the carrier frequency of an optical pulse is shifted without changing its shape. The efficiency of the device takes advantage of slow group velocities of light attainable in periodic photonic structures. The frequency shifting effect is quantitatively studied by…
We investigated the structural, magnetic, transport, and thermoelectric properties of polycrystalline delafossite oxides, $\mathrm{Cu}{\mathrm{Cr}}_{1\ensuremath{-}x}{\mathrm{Mg}}_{x}{\mathrm{O}}_{2}$ $(0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.04)$. We found that, with the substitution of ${\mathrm{Mg}}^{2+}$ i…
We report for the first time on rich and tunable transport phenomena in closed-packed arrays of PbSe colloidal nanocrystals (NCs) in the form of thin films. As the interdot coupling is increased, the system evolves from an insulating regime dominated by Coulomb blockade to a semiconducting regime, where hopping conduc…
We construct multi-field generalisations of the Cosserat continuum model on the basis of the square lattice model that takes into account rotational degree of freedom of microstructural elements. This approach allows us to model not only long but also short wavelength fields of displacements and rotations. The accurac…
We found a new cobalt oxide (CaOH)1.14CoO2 by utilizing the high-pressure technique. X-ray and electron diffraction studies revealed that the compound has layer structure which consists of CdI2-type CoO2 layers and rock-salt-type double CaOH atomic layers. The two subcells have incommensurate periodicity along the a-a…
Abstract The equations needed to correctly interpret both AC and DC conductivity results of single wall carbon nanotube (SWNT) polymer composites and the scaling of these results onto a single master curve are presented. Brief discussions on the factors that determine the critical volume fraction (ϕ c ) and the percol…