Materials Literature
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Abstract A novel approach to the preparation of polyethylene (PE) nanocomposites, with montmorillonite/silica hybrid (MT‐Si) supported catalyst, was developed. MT‐Si was prepared by depositing silica nanoparticles between galleries of the MT. A common zirconocene catalyst [bis(cyclopentadienyl)zirconium dichloride/met…
The cofacial bisporphyrins H4DPS (DPS = 4,6-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]dibenzothiophene), H4DPO (DPO = 4,6-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]dibenzofuran), H4DPX (DPX = 4,5-bis[5-(2,8,13,17-tetraethyl-3,7,12,18-tetramethylporphyrinyl)]-9,9-dimethylxanthene…
We consider a quantum dot coupled to two BCS superconductors with same gap energies $Δ$. The transport properties are investigated by means of infinite-$U$ noncrossing approximation. In equilibrium density of states, Kondo effect shows up as two sharp peaks around the gap bounds. Application of a finite voltage bias l…
From density functional calculations, we show that localized states stemming from defects or topological disorder exhibit an anomalously large electron-phonon coupling. We provide a simple analysis to explain the observation and perform a detailed study on an interesting system: amorphous silicon. We compute first pri…
A recent report [Kiguchi {\it et al.}, Phys. Rev. B {\bf 68}, 115402 (2003)] that the (111) surface of 5 MgO layers grown epitaxially on Ag(111) becomes metallic to reduce the electric dipole moment raises a question of what will happen when we have fewer MgO layers. Here we have revealed, first experimentally with el…
We have developed a new technique for photothermal displacement spectroscopy that is potentially orders of magnitude more sensitive than conventional methods. We use a single Fabry-Perot resonator to enhance both the intensity of the pump beam and the sensitivity of the probe beam. The result is an enhancement of the…
We present a femtosecond time-resolved optical spectroscopy (TRS) as an experimental tool to probe the changes in the low energy electronic density of states as a result of short and long range charge density wave order. In these experiments, a femtosecond laser pump pulse excites electron-hole pairs via an interband…
A simple and effective method denoted “pH-adjusting” is used to graft a large amount of heteroatoms such as Al and Ti to mesoporous silica material SBA-15. The products prepared by this method show highly ordered mesostructures with large surface areas and uniform mesopore size distribution. The results of ICP, EDX, 2…
Two crystals of lindackerite, ideally (Cu,Co,Ni)Cu 4 (AsO 4 ) 2 (AsO 3 OH) 2 . 9 H 2 O from Jachymov (formerly St. Joachimsthal), Czech Republic, were studied and found to be essentially isostructural. The microprobe analysis of the first sample yielded (in wt%): As 29.66, Cu 27.85, Co 1.50, Ni 0.83,O 39.96, sum 99.79…
We show that an analysis of the intensity versus energy variation of Bragg spots due to low-energy electron diffraction from a disordered overlayer of molecules on a crystal surface allows a much more convenient method of determining the local adsorption geometries of such molecules than previously analyzed weak diffu…
Recent studies of carbon fiber and carbon/glass hybrid laminates have reported compression strengths and failure strains which are borderline for wind turbine blade designs, depending upon the reinforcement architecture, matrix resin, and environment. Compressive strength is known to be sensitive to the straightness o…
The relative proportions of the minerals in a series of slates from the Iberian Massif in northwestern Spain, quarried and used for roofing purposes, have been evaluated using X-ray powder diffraction and the Rietveld-based SIROQUANT data processing system. Information on the chemical composition of the chlorite, mica…
Ultrahigh-density storage devices consisting of poling reversed nanodots are examined using a scanning nonlinear dielectric microscope (SNDM). By using the SNDM, real-time observation of the poling direction was attempted and an unexpected phenomenon was discovered. For lithium tantalite films thicker than 350 nm, pol…
A novel parameterization of x-ray interaction cross-sections is developed, and employed to describe the x-ray linear attenuation coefficient and mass energy absorption coefficient for both elements and mixtures. The new parameterization scheme addresses the Z-dependence of elemental cross-sections (per electron) using…
90° elastic domains were observed after local polings in epitaxial ferroelectric Pb(Zr0.2Ti0.8)O3 thin films via piezoresponse force microscopy. An area of internal stress arises under a conductive atomic force microscope tip due to the opposite signs of the converse piezoelectric effects in the switched domain and th…
The ground-state polarization of BaTiO3 nanosized films and cells is studied using an atomic-level simulation approach based on a shell model with parameters obtained from first-principles calculations. We demonstrate that the critical thickness for ferroelectricity in a free-standing BaTiO3 stress-free film is 3.6 nm…
We report an alternative way of preparing high-quality single-wall carbon nanotubes (SWCNTs). Using a triple-layer thin film of Al/Fe/Mo (with Fe as a catalyst) on an oxidized Si substrate, the sample is exposed to a single short burst (5 s) of acetylene at 1000 °C. This produced a high yield of very well graphitized…
Pertsevite is a new Mg borate from a contact-metasomatic kotoite marble from the region east of Verkhoyansk, Sakha-Yakutia, northeastern Siberia. The end member is defined as Mg 2 BO 3 F, which is the composition of a synthetic phase. The natural material consistently contains from 4 to 12 wt.% SiO 2 as well as some O…
Coaxial nanocables composed of a uniform single‐crystalline β‐SiC core, an amorphous SiO 2 intermediate layer, and a graphitic carbon sheath (see Figure) have been synthesized via a simple chemical vapor deposition route. By annealing the nanocables, chains of carbon nanotube–SiC heterojunctions have been prepared. Th…
The purpose of this paper is to explain why the standard continuum theory fails to properly describe certain mechanical phenomena and how the description can be improved by enrichments that incorporate the influence of gradients or weighted spatial averages of strain or of an internal variable. Three typical mechanica…