Materials Literature
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An electroactive polymer-ceramic hybrid actuation system (HYBAS) was recently developed. The HYBAS demonstrates significantly enhanced electromechanical performance by utilizing the advantages of cooperative contributions of the electromechanical responses of an electrostrictive copolymer and an electrostrictive singl…
By utilizing a sharp magnetic needle made of a sintered Nd2Fe14B permanent magnet, we were able to produce a strong magnetic field of up to approximately 560kA∕m in a transmission electron microscope and succeeded in observing the magnetization reversal in a thin film of sintered Nd2Fe14B by in situ Lorentz microscopy…
Abstract Summary: Nano‐polyethylene fibers and floccules were prepared under atmospheric pressure via ethylene extrusion polymerization in suit, using the SBA‐15‐supported Cp 2 ZrCl 2 catalytic system. The major morphology units in the samples were fibers and floccules. The diameter of the single nano‐fibers was 120–2…
Abstract The results of the density functional (DFT) LCAO and plane wave (PW) calculations of the electronic and structural properties of four known SrZrO 3 phases (Pm3m, I4/mcm, Cmcm and Pbnm) are presented and discussed. The calculated unit cell energies and relative stability of these phases agree well with the exp…
Four kinds of silica sols in butyl acetate with different particle sizes were prepared and modified by vinyl triethoxysilane. The modified silica can be directly used to prepare solvent-borne acrylic-based polyurethane-nanosilica composites via in situ polymerization. It was found that the modified silica particles co…
The structural and electronic properties of Gd2(Ti1−yZry)2O7 (y=0–1) pyrochlores following a 2.0-MeV Au2+ ion-beam irradiation (∼5.0×1014Au2+∕cm2) have been investigated by Ti2p and O1s near-edge x-ray absorption fine structure (NEXAFS). The irradiation of Gd2(Ti1−yZry)2O7 leads to the phase transformation from the or…
We have measured the double-to-single photoionization ratio of beryllium $(1{s}^{2}2{s}^{2})$ between 28 and $40\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ and determined the relative single- and double-photoionization cross sections. In this energy region only simultaneous but not sequential emission of both $2s$ electro…
Structural characterization via transmission electron microscopy and atomic force microscopy of arrays of small Si nanocrystals embedded in SiO2, important to many device applications, is usually difficult and fails to correctly resolve nanocrystal size and density. We demonstrate that scanning tunneling microscopy (S…
Translational tracer diffusion of spherical macromolecules in crowded suspensions of rodlike colloids is investigated. Experiments are done using several kinds of spherical tracers in fd-virus suspensions. A wide range of size ratios L/2a of the length L of the rods and the diameter 2a of the tracer sphere is covered…
The development of permanent lunar bases is constrained by performance of construction materials and availability of in-situ resources. Concrete seems a suitable construction material for the lunar environment, but water, one of its major components, is an extremely scarce resource on the Moon. This study explores an…
Abstract Summary: The difference between the melting temperatures of poly(propylene) (PP) fibre and random poly(propylene‐ co ‐ethylene) (PPE) was exploited in order to establish processing conditions for an all PP composite. Under these conditions the matrix must be a liquid in order to ensure good wetting and impreg…
Chinese celadon shards of the Longquan type, believed to date from the Southern Song dynasty (1127-1279 AD), were excavated in 1934 on Mapungubwe Hill, a 13th century Iron Age site in the Limpopo valley, South Africa. We studied the shards with Raman spectroscopy, X-ray fluorescence spectroscopy (XRF) and X-ray diffra…
We report Mn-doped GaN nanowires exhibiting ferromagnetism even at room temperature. The growth of single-crystalline wurtzite-structured GaN nanowires doped homogeneously with about 5 at. % Mn was achieved by chemical vapor deposition using the reaction of Ga∕GaN∕MnCl2 with NH3. The ferromagnetic hysteresis at 5 and…
The mechanical properties of composites based on different natural fibers and glass fibers using unsaturated polyester and modified acrylic as matrix are evaluated. In spite of the several works done in natural fiber composites, there are very few results on acrylic as matrix. Fabrication of the composites is done by…
Gold can activate propene or influence titania such that a reaction occurs in which bidentate propoxy species are formed on the catalyst (see picture). In the absence of gold this reaction is not possible. This observation brings the understanding of this unique catalyst system one step further.
Abstract Nanosilica particles were directly introduced into polyester polyol resins through in situ polymerization and blending methods, then cured by isophorone diisocyanate (IPDI) trimers to obtain nanocomposite polyurethanes. FTIR and TGA analyses indicated that more polyester segments had reacted with silica parti…
Systematic efforts to synthesise fullerene containing LCs have produced a variety of successful model compounds. We present a simple molecular theory relating the self-organisation observed in these systems to their molecular structure. The interactions are modelled by dividing each molecule into a number of sub-molec…
We derive a formal expression for Wannier functions of composite bands of one-dimensional (1D) Bloch electrons in terms of parallel-transported Bloch functions and their non-Abelian geometric phases. Spatial decay properties of these Wannier functions are studied in the case of simple bands of 1D model insulators and…
We formulate the configurational partition function for dendrimers, taking explicit account of their conformations and segmental interactions. Two approximate schemes are presented, one based on the effective dendrimer-dendrimer interactions and the other based on the interactions among the mesogenic units comprising…
We report the development of high-mobility carbon-nanotube thin-film transistors fabricated on a polymeric substrate. The active semiconducting channel in the devices is composed of a random two-dimensional network of single-walled carbon nanotubes (SWNTs). The devices exhibit a field-effect mobility of 150cm2∕Vs and…