Materials Literature
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Computer modeling of the variable-range-hopping (VRH) conductivity in two-dimensional systems has been done by a kinetic Monte Carlo method, which includes some new elements. Study of the temperature dependence of the conductivity, testing of the different scaling relations, and study of the size effect show the detai…
The role of proteins in biomineralization and the mechanism of eggshell formation are not well understood. We have isolated and purified the major protein, ansocalcin from goose eggshell matrix. The amino acid sequence study indicates that ansocalcin is homologous to the chicken eggshell protein, ovocleidin 17, and C-…
Tunneling junctions of stacked monolayers of uniform, organically functionalized ${\mathrm{Fe}}_{3}{\mathrm{O}}_{4}$ nanocrystals of 5.5 nm average diameter were prepared. Current-voltage characteristics of the junctions were studied as function of temperature and magnetic field. An abrupt increase in the resistance w…
Supramolecular systems--their successes, problems, and potential--are discussed with allusion to specific examples.
We have constructed microscopic, structurally relaxed atomistic models of $\mathrm{Si}/{\mathrm{SiO}}_{2}$ superlattices. The structural distortion and oxidation-state characteristics of the interface Si atoms are examined in detail. The role played by the interface Si suboxides in raising the band gap and producing d…
Diffuse neutron scattering is a valuable tool to obtain information about the size and orientation of the polar nanoregions that are a characteristic feature of relaxor ferroelectrics. In this paper, we present new diffuse scattering results obtained on Pb(Zn1/3Nb2/3)O3 (PZN for short) and (1-x)Pb(Zn1/3Nb2/3)O3-xPbTiO…
The wave function and binding energy for shallow donors in GaAs are calculated within the tight binding (TB) approach, for supercells containing up to two million atoms. The resulting solutions, coupled with a scaling law, allow extrapolation to the bulk limit. A sharp shallow-deep transition is obtained as the impuri…
The experimental and theoretical challenges posed by the study of dynamically inhomogeneous systems are outlined in the context of cuprates and other oxides. Considering the pitfalls in the single-component approach to the analysis of inhomogeneous systems, the effect of either temporal or spatial averaging by differe…
Based on the many-body theory of metals in the third order of the perturbation expansion in electron-ion interaction pseudopotential, the potentials of pair and three-ion interactions are calculated in liquid lead, aluminium and beryllium at their melting temperatures. The reducible and irreducible three-ion interacti…
SBA-15 mesoporous silica has been functionalized with arenesulfonic acid groups by means of a one-step simple synthesis approach involving co-condensation of tetraethoxysilane (TEOS) and 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (CSPTMS) in the presence of a poly(alkylene oxide) block copolymer (Pluronic 123) un…
Since their introduction in 1985 by Tomalia et al. (1) and Newkome et al. (2), dendrimers have attracted much attention because of their fascinating structure and unique properties (3, 4). Dendrimers are globular, size monodisperse macromolecules in which all bonds emerge radially from a central focal point or core wi…
Characterization of the physical properties of protein surface hydration water is critical for understanding protein structure and folding. Here, using molecular dynamics simulation, we provide an explanation of recent x-ray and neutron solution scattering data that indicate that the density of water on the surface of…
Gold nanorods were prepared via a seed-mediated sequential growth process involving the use of citrate-stabilised seed crystals and their subsequent growth in a series of reaction solutions containing [AuCl4]−, ascorbic acid and the cationic surfactant cetyltrimethylammonuim bromide (CTAB). Electron diffraction analys…
Fine structures in electron energy-loss spectra, observed 30-40 eV beyond the threshold of oxygen K-edges in perovskite-type manganites BiMnO3 and LaMnO3, are discussed. LaMnO3 with orthorhombic symmetry (space group Pbnm) shows a clear peak in this region. However, BiMnO3 with a heavily distorted perovskite-type stru…
Der Zusammenhalt von Riesenvesikeln kann durch Substanzen wie Poly-L-lysin (kationisch), Polyvinylpyrrolidon (nichtionisch) und Heparin (anionisch) gefördert oder verhindert werden. Dies lässt sich mikroskopisch verfolgen; bei einem elektrostatisch zusammengehaltenen Paar von Vesikeln erwies sich die Adhäsion als zeit…
CuS 2 and CuSe 2 with pyrite structures were systematically studied by transport, magnetization, and specific-heat measurements. In remarkable contrast to other 3d transition-metal pyrites, a clear indication of strong electron correlations was absent in the electronic properties of Cu pyrites. We interpret this as a…
Ein Back-to-Front-Ansatz für die Synthese von Azuliporphyrinen aus einem Azulipyrran 1 wurde entwickelt. Mit dieser Methode gelang erstmals die rationale Synthese des Dicarbaporphyrinoids 2.
Abstract New phenolic hydroxyl‐pendant aromatic polyimides were synthesized with the N ‐silylated diamine method in two steps: the ring‐opening polyaddition of tetrakis(trimethylsilyl)‐substituted 4,4′‐diamino‐3,3′‐dihydroxybiphenyl to various aromatic tetracarboxylic dianhydrides, giving trimethylsiloxy‐pendant poly(…
The cooling effect of an ambient gas on arc discharge for the growth of carbon nanotubes has been investigated in terms of the diameter of the nanotube. A small diameter nanotube with high purity is successfully obtained by cooling of ambient He gas using a water-cooling coil placed around the arc discharge. Furthermo…
An in-situ modified sol–gel method for the preparation of a Ni-based monolith-supported catalyst is reported. With the presence of a proper amount of plasticizer and binder, and at an optimized pH value, the stable boehmite sol was modified with metal ions (Ni, Li, La) successfully without distinct growth of the parti…