Materials Literature
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Abstract Nanocomposites containing a thermoplastic blend and organophilic layered clay (organoclay) were produced by melt compounding. The blend composition was kept constant [polyamide 6 (PA6) 70 wt % + polypropylene (PP) 30 wt %], whereas the organoclay content was varied between 0 and 10 wt %. The mechanical proper…
We study the electron-phonon interaction in the strongly correlated superconducting cuprates. Two types of the electron-phonon interactions are introduced in the $t-J$ model; the diagonal and off-diagonal interactions which modify the formation energy of the Zhang-Rice singlet and its transfer integral, respectively.…
We have studied a variety of different disordered materials, including molecular and ionic liquids, supercooled liquids, glasses, ionic conductors, and doped semiconductors, in ac electromagnetic fields over an exceptional broad dynamic range, including the rarely investigated GHz to THz region. All classes of disorde…
Controlling the size, shape and structure of nanocrystals is technologically important because of the strong effect of size and shape on optical, electrical, and catalytic properties. Monodispersed nanocrystals of copper oxide were prepared by the precipitation–pyrolysis method. By controlling the starting materials,…
Abstract In this study, electrospinning was used to fabricate ethyl–cyanoethyl cellulose [(E‐CE)C] fiber from a solution of (E‐CE)C/tetrahydrofuran. The diameter of the thinnest fiber fabricated during the electrospinning was about 200 nm. It was found that the diameters of the fibers and their distribution depend on…
A possibility is discussed of observing spin injection effect on the ferromagnet domain structure by means of resonant excitation of the domain wall oscillations by a spin-polarized ac injection current. The natural frequency of the domain wall oscillations in a thin ferromagnetic film with parallel anisotropy is calc…
We have used positron annihilation spectroscopy to determine the nature and the concentrations of the open volume defects in as-grown and electron irradiated (${E}_{\mathrm{e}\mathrm{l}}=2\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$, fluence $6\ifmmode\times\else\texttimes\fi{}{10}^{17}\text{ }{\mathrm{c}\mathrm{m}}^{\ensu…
We demonstrate that the 3.42 eV photoluminescence (PL) band in GaN is of the same intrinsic origin as the near-edge $\sim$3.47 eV band, but arises from regions of inversed polarity characterized by different strain and growth rate. Two absorption edges are thermally detected at 0.35 K in nanocolumn structures, exhibit…
The polymorphism of cyclopentanol (C 5 H 10 O) has been further investigated by X-ray powder diffraction experiments and it has been found to agree with the most recent thermodynamic study [ J. Chem. Thermodyn. 1995, 27, 953]. In addition to the previously reported orientationally disordered hexagonal phases I and II,…
The crystal structure of lithium manganese vanadate, LiMnVO4, is characterized by chains of edge-sharing MnO6 octahedra, bridged by pairs of edge-sharing LiO4 and VO4 tetrahedra. Cation–cation repulsions displace the V and Li ions from the tetrahedral centres and deform the tetrahedra further by shortening the mutuall…
Takovites are nickel-based layered double hydroxides (LDHs) with a general formula that can be written as Ni 1 - x Al x (OH) 2, A z - x / z, y H 2 O, where A is a compensating interlayer anion. As in some other LDH samples, the positive charge of the layer can be adjusted upon synthesis and various anions can be excha…
Molecules that associate to form porous networks can be made by attaching multiple hydrogen-bonding sites to suitable cores. Pentaerythrityl tetraphenyl ether, a four-armed core, is the progenitor of dendritic derivatives with more arms, including dipentaerythrityl hexaphenyl ether 7. An advantage of such dendritic de…
Metal−insulator core−shell structures have been demonstrated to have interesting and tunable optical properties. Systems previously investigated include silica-capped gold particles and gold shells surrounding silica particles. However, many of the systems studied so far have been spherical (or zero-dimensional). Thus…
The crystal structure of monobarium dititanium pentaoxide, BaTi(2)O(5), synthesized by a floating-zone method, was studied by X-ray diffraction. Previous reports describe the structure as being in the monoclinic centrosymmetric space group C2/m. We have recently found that this material exhibits ferroelectricity, and…
Nanocrystalline mesoporous tin dioxide materials have been obtained through the controlled hydrolysis of bis(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin followed by a thermal treatment at 400−550 °C. These materials have been carefully characterized by elemental analysis, FTIR, TGA-MS, XRD, MET, N 2 adsorption, and…
The relaxation phenomenon around 1300 K in LaMn 0.5 Co 0.5 O 3+ δ and their valence states of Mn and Co atoms were investigated by TG-DTA, powder X-ray diffraction, magnetic susceptibility, and XANES of two samples cooled at 10 Kh - 1 in the range 1673−973 K and quenched from 1673 K. DTA clarified that the relaxation…
Self-assembled polyester dendritic bow-ties with various peripheral groups were prepared, and their association constants were measured by (1)H NMR in CDCl(3). The two complementary dendrons were prepared by attachment of either a bis(adamantylurea) or a glycinylurea to the focal point of the dendron. The parent self-…
Heavily doped diamond films are quite actively studied for their promising applications in industrial as well as in fundamental electrochemistry (both for physicochemical studies and in the field of electroanalysis), because of their very high stability toward chemical and electrochemical oxidative attacks. Fluorinate…
A novel class of phenylphosphine oxide (PPO) containing perfluorocyclobutyl (PFCB) polymers has been developed for potential use as multifunctional materials in space environments. The reaction of p -BrArOCF CF 2 (for Ar = phenyl and biphenyl) with tert -butyllithium affords the lithium reagent smoothly below −20 °C.…
The interpretation of diffraction and spectroscopic data on clay minerals can be facilitated by first-principles quantum mechanical simulations based on density functional theory (DFT), which now has achieved sufficient accuracy to predict crystallographic properties of these minerals without recourse to empirical par…