Materials Literature
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The scaling of the bond-bond correlation function ${P}_{1}(s)$ along linear polymer chains is investigated with respect to the curvilinear distance $s$ along the flexible chain and the monomer density $\ensuremath{\rho}$ via Monte Carlo and molecular dynamics simulations. Surprisingly, the correlations in dense three-…
We report the controlled chemical vapor deposition (CVD) growth of single-walled carbon nanotubes (SWNTs), using ethanol as the carbon feedstock and bimetallic CoMo-doped mesoporous silica (SBA16) as the catalyst. Ultralong (up to 4 mm) and horizontally aligned SWNTs can be grown directly on flat substrates or across…
Novel pyboxazines and the known pybox ligands are used in the ruthenium-catalyzed asymmetric epoxidation of olefins with H2O2 (see scheme). This new catalytic system is successful in the conversion of differently substituted aromatic olefins and gives ee values of up to 84 %.
To investigate the relation of in‐plane fabric tensile properties with woven fabrics bagging behavior, a new test method was developed and a real time data acquisition and strain gauge technique were used. The bagging procedure was carried out while the woven fabric tensile deformations along warp and weft directions…
We report on the discovery of a large, room temperature magnetoresistance (MR) effect in polyfluorene sandwich devices in weak magnetic fields. We characterize this effect and discuss its dependence on voltage, temperature, film thickness, electrode materials, and (unintentional) impurity concentration. We usually obs…
The effects of natural Artemisia oil on the corrosion of steel in molar hydrochloric acid were studied by the measurements of weight loss, electrochemical and EIS polarisation. The results obtained revealed that Artemisia oil reduced the rate of corrosion. The corrosion inhibition efficiency increased with the increas…
The paper presents asymptotic analysis of an eigenvalue problem for the Helmholtz operator in a periodic structure involving split-ring resonators [originally proposed in J. B. Pendry et al., IEEE Trans. Microwave Theory Tech. 47, 2075 (1999)]. The eigensolutions are sought in the form of Bloch waves. The main emphasi…
In the active search for potentially promising candidates for spintronic applications, we focus on the intermetallic ferromagnetic Mn5Ge3 compound and perform accurate first-principles FLAPW calculations within density functional theory. Through a careful investigation of the bulk electronic and magnetic structure, ou…
Photoluminescence study using the 325 nm He-Cd excitation is reported for the Au nanoclusters embedded in SiO2 matrix. Au clusters are grown by ion beam mixing with 100 KeV Ar+ irradiation on Au [40 nm]/SiO2 at various fluences and subsequent annealing at high temperature. The blue bands above ~3 eV match closely with…
Gutsy chemistry: A solvothermal process has been developed for the controlled creation of interior space in TiO2 intestines (either hollow (see TEM image) or partially filled) or spheres in the anatase polymorph. A morphological transformation from intestine to sphere is observed when the water content of the water/2-…
A bicontinuous cubic structure was revealed by electron crystallography on a large-pore mesoporous silica with a cubic Iad symmetry synthesized by using a triblock copolymer as a structure-directing agent. Its reconstructed structure (picture, left) is composed of an enantiomeric pair of interwoven three-dimensional m…
We report the results of a model calculation for studying the effects of hydrostatic pressure on a bunch of carbon nanotubes. At pressures that we work with, the deformation in axial direction comes out to be negligibly small. We find that hydrostatic pressure is an ideal probe to study the radial deformations of the…
If metal surfaces are exposed to sufficiently oxygen-rich environments, oxides start to form. Important steps in this process are the dissociative adsorption of oxygen at the surface, the incorporation of O atoms into the surface, the formation of a thin oxidic overlayer and the growth of the once formed oxide film. F…
Charge and orbital ordering in the low-temperature monoclinic structure of magnetite (Fe3O4) is investigated using the local spin density approximation with Coulomb interaction correction method. While the difference between t(2g) minority occupancies of Fe(2+)(B) and Fe(3+)(B) cations is large and gives direct eviden…
The electrospinning process was used successfully to embed single-walled carbon nanotubes (SWCNTs) in a poly(ethylene oxide) (PEO) matrix, forming composite nanofibers. Initial dispersion of SWCNTs in water was achieved by the use of an amphiphilic alternating copolymer of styrene and sodium maleate. The resulting dis…
Dry films: An electrospinning process was used to form films with high water contact angles (166.7°) and low sliding-angles (4.3°). The electrospun films exhibit excellent superhydrophobic Cassie-regime stability: The figure shows a nonwetting water droplet, even after 400 Pa of uniaxial loading.
Spider silk proteins have mainly been investigated with regard to their contribution to mechanical properties of the silk thread. However, little is known about the molecular mechanisms of silk assembly. As a first step toward characterizing this process, we aimed to identify primary structure elements of the garden s…
Solution-phase synthesis of single-crystal ZnO disks and rings was achieved in high yield at low temperature (70–90 °C) by using an anionic surfactant as a template. The reaction can be controlled by means of the growth temperature and the molar ratio of reagents to favor formation of disks or rings. A growth mechanis…
This Letter reports the laser energy dependence of the Stokes and anti-Stokes Raman spectra of carbon nanotubes dispersed in aqueous solution and within solid bundles, in the energy range 1.52--2.71 eV. The electronic transition energies (${E}_{ii}$) and the radial breathing mode frequencies (${\ensuremath{\omega}}_{\…
Highly c-axis oriented CaRuO3 thin films were prepared on LaAlO3 buffered Si(100) substrates at 650 °C by pulsed laser deposition. The buffer layer had a significant effect on the microstructure and electrical properties of the subsequent CaRuO3 thin films. Typical columnar grown CaRuO3 films were available using LaAl…