Materials Literature
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Improved diffraction efficiencies can be obtained in the paraxial domain of diffractive optics by considering light explicitly as an electromagnetic rather than a scalar field because of the extra freedoms provided by the state of polarization. For example, diffractive beam splitters with 100% efficiency are made poss…
Surface spallation of gelcast alumina green bodies due to the exposure of the surface to air during gelation was successfully eliminated by adding a proper amount of poly(vinylpyrrolidone) (PVP) in aqueous acrylamide premix solution. The influences of PVP on the colloidal characteristics of alumina powder in aqueous s…
Thickness dependence of leakage current behavior in Pt/(Ba,Sr)TiO3/Pt film capacitors was investigated by fabricating epitaxial (Ba,Sr)TiO3 thin films having different thicknesses of 55–225 nm but with an identical interface state on Pt(001)/MgO(001) substrates by a radio-frequency magnetron sputtering technique. In t…
Abstract Kevlar fibers (DuPont) and glass fibers have been used to reinforce linear lowdensity polyethylene (LLDPE) by using an elastic melt extruder and the compression molding technique. The impact behavior of hybrid composites of different compositions is compared and has been explained on the basis of volume fract…
The atomic-force microscopy method is used to study the structure of the surface and the formation of a dislocation spiral on the (010) face of a potassium hydrogen phthalate crystal grown from a water-alcohol solution. It is shown that the face grows according to the dislocation mechanism. Channels surrounding disloc…
The potential applications of diamond in the field of electronics working under high power and high temperature (aeronautic, aerospace, etc.) require highly oriented films on heterosubstrates. This is the key motivation of the huge research efforts that have been carried out during the last ten years. Very significant…
Abstract PbSe nanowires with an average size of 8 × 350 nm were synthesized by the reaction of Pb(NO 3 ) 2 and Se powder at 60 °C under ambient pressure. A mixture of arachidic acid (AA, n ‐C 19 H 39 COOH) and octadecylamine (ODA), which could form a complex with Pb 2+ , was employed as a soft template to control the…
Bistability is reported in sensitized Er3+ luminescence driven by an Yb3+ transition that previously revealed an Yb3+ luminescent instability. To our knowledge this is the first report of bistable energy transfer between different rare-earth ions.
Abstract Titanium was introduced into the clay structure by cation exchange with polymeric Ti cations which were formed by partial hydrolysis of Ti alkoxide in HCl. X-ray diffraction, N 2 adsorption-desorption, chemical analysis, thermogravimetric analysis, differential thermal analysis, temperature-programmed desorpt…
The metal-insulator transition (MIT) of V 6 O 11 is studied by means of electronic structure calculations using the augmented spherical wave method. The calculations are based on density functional theory and the local density approximation. Changes of the electronic structure at the MIT are discussed in relation to t…
Dielectric and magnetoelectric properties are reported in magnetoelectric (ME) composites containing lead doped barium titanate as the electrical component and a mixed Ni-Co ferrite as the magnetic component. Changes were observed in dielectric properties as well as in the ME effect as the molar ratio of the component…
Nous decrivons ici la bobjonesite, V 4 + D (S0 4 ) (H 2 0) 3 , nouvelle espece minerale decouverte au mont Temple, comte d'Emery, au Utah. On la trouve en croutes bleu-vert et en efflorescences le long de fissures dans un arbre fossilise d'âge triassique. Les cristaux sont sub-millimetriques et intimement enchevetres.…
The synthesis, phase properties and electro-optic response of two new chiral low molar mass organosiloxane liquid crystalline materials are presented. The structure of the molecule contains a short (three silicon atoms) siloxy chain attached via a hydrocarbon chain to the non-chiral end of a chiral mesogenic moiety. T…
Abstract The previously unknown crystal structure of the basic lead nitrate Pb 2 (OH) 3 (NO 3 ) has been determined using single-crystal X-ray diffraction data (Mo-Kα radiation, CCD area detector). The compound is orthorhombic, space group Immm, with a = 8.314(2), b = 8.545(2), c = 17.210(3) Å (R1 = 2.78% for 940 ‘obs…
Abstract Neutron diffraction provides an experimental method of directly locating hydrogen atoms in proteins, and the development of the neutron imaging plate (NIP) became a breakthrough event in neutron protein crystallography. The general features of the NIP are reviewed. A high resolution neutron diffractometer ded…
Nanowires of magnetic metals (Fe, Co, Ho, Gd) have been synthesized inside the hollow interiors of single-wall carbon nanotubes (SWNTs) by filling SWNTs with precursor metal chlorides and subsequent reduction. SWNTs have been filled by either the melt-phase sealed-tube reaction or a solution-phase method. Among the me…
Single-walled carbon nanotubes prepared by disproportionation of CO over Co-Mo/SiO2 catalysts have been characterized by Raman spectroscopy, using several excitation energies. By varying the reaction temperature, different ranges of nanotube diameter were obtained. The average diameter of a single-walled nanotube prod…
Features of the diffuse phase transition in lead barium niobate (PbxBa1−xNb2O6–PBN) ferroelectric ceramics are presented and discussed. Ceramics were prepared near to the morphotropic phase boundary (x∼0.63) and the dielectric properties were investigated. The character of the ferroelectric phase transition was carefu…
Sphingomonas sp. A1 possesses a high molecular weight (HMW) alginate uptake system composed of a novel pit formed on the cell surface and a pit-dependent ATP-binding cassette (ABC) transporter in the inner membrane. The transportation of HMW alginate from the pit to the ABC transporter is mediated by the periplasmic H…
Abstract The combination of stroboscopic techniques and neutron diffraction can be used to study the kinetics of structural changes in condensed matter on a microscopic level. Transient states may be identified and characterized on time-scales down to the microsecond regime. Hence, valuable information about the under…