Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
The fracture toughness of ceramics can be improved by the incorporation of a variety of discontinuous, elastic reinforcing phases that generate a crack‐bridging zone. Recent models of toughening by crack‐bridging processes are discussed and used to describe the behavior observed in whisker‐reinforced ceramics. The tou…
International audience
Abstract Hydrosilation of methylenecyclohexane and hex‐1‐ene by octa(hydridosilsesquioxane) catalysed by hexachloroplatinic acid is a new route to polyhedral organylsilsesquioxanes. Quantitative yield of octa(cyclohexylmethylsilsesquioxane) is reached. This reaction opens a vast field of yet unknown polyhedral silsesq…
Abstract The efficiency of aromatic ketones as singlet‐oxygen ( 1 O 2 ( 1 Δ g )) sensitizers can vary considerably with the electronic configuration of their lowest triplet state and the solvent used. Near‐infrared measurements of tie luminescence of singlet oxygen have shown that the quantum yield of singlet‐oxygen p…
Co K-edge near-edge X-ray absorption spectra are reported for RECoO 3 (RE=Y, Ho, Gd, Nd) at 300 K and for LaCoO 3 in the temperature range (140<or=T<or=830 K). The pre-edge structure associated with Co 1s to 3d excitation is found to be comparable for all the cobaltates at room temperature, consistent with the propose…
When polyimide (Kapton) or polybenzimidazole (PBI) are irradiated by a 248 nm KrF laser, their electrical conductivity is increased permanently. Conductivity increases of up to fifteen orders of magnitude were observed, and conductivities on the order of 1–10 Ω−1 cm−1 were obtained. The laser-induced conductivity incr…
We have developed an acellular matrix vascular prosthesis (AMVP) made by detergent and enzymatic extraction of natural arteries, yielding a tissue framework of collagen and elastin from the original vessel, with preservation of the natural basement membrane at the blood flow surface. These biografts have excellent han…
It is shown that, given two arbitrary lattices of equal density in the Euclidean space R n , a bounded quasi-periodic and piecewise affine vector field nu on R n (a so-called 'modulation field') can be built so that the second lattice is the image of the first one under the map x to x-v(x). The proof relies on a facto…
Experimental verification is made of a new polarization splitter which utilizes artificial anisotropic dielectrics. The splitter is composed of layers of periodically laminated SiO2/TiO2 thin films. The SiO2 and TiO2 films are alternately deposited by rf sputtering and reactive dc sputtering, respectively. The thickne…
Cathodoluminescence (CL) and annealing studies of microwave plasma-assisted chemical vapor deposited (CVD) diamond films were carried out. The annealing behavior of the 1.681 eV (737.4 nm) line in the CL spectra of CVD diamond films grown on Si substrates is compared with that of the GR1 spectral line (1.673 eV) of na…
Raman scattering experiments have been carried out on powdered samples of cupric oxide (CuO) grown with the 18 O isotope. The phonon frequencies have been measured and compared to those of Cu 16 O. The isotopic frequency shifts of the phonon modes have also been compared with the predictions of a lattice dynamics mode…
Common and Newton black films, which are the ultimate stage of thinning of soap films, are investigated by absolute x-ray reflectivity. The challenging and open problem concerning these two systems is the determination of the equilibrium thickness of the aqueous core. X-ray reflectivity provides very detailed and new…
The electronic structures are calculated for several crystalline approximants of quasicrystals, AlCuLi and AlFe. The densities of states of these systems, and also of AlMn, suggest universality of the pseudogap at the Fermi energy in quasicrystals. The pseudogap satisfies a Hume-Rothery--type relation. The origin of t…
Abstract A series of segmented polyurethanes from two polyols, 4,4′‐diphenylmethane diisocyanate (MDI) and butane diol was synthesized. The degree of chemical crosslinking was controlled by varying the ratio of poly(oxypropylene) diol to poly(oxypropylene/oxyethylene) triol. The samples were prepared at the stoichiome…
Abstract Oxygen plasma treatment of polypropylene (PP) surfaces led to introduction of oxygencontaining functionalities, with consequent improvement of surface wettability. A combination of X‐ray photoelectron spectroscopy (XPS), static secondary ion mass spectroscopy (SSIMS), and contact angle measurements (water‐in‐…
Abstract A comprehensive 13 C‐NMR method for the analysis of composition in the most common commercial polyethylene copolymers has been established. The method covers ethene copolymers with propene, butene‐1, hexene‐1, octene‐1, and 4‐methyl pentene‐1 in the composition range of 1–10 mol %. The chemical shift assignme…
A novel open antimony sulfide framework of composition [Sb(3)S(5)](-) has been synthesized hydrothermally, in the presence of tetramethyl ammonium ions. Determination of the crystal structure demonstrates that the (Me(4)N)(+) molecules (Me, methyl) occlude a system of intersecting channels at 90 degrees to one another…
This textbook describes the fundamental principles of structural phase transitions in materials in an easily understandable form, suitable for both undergraduate and graduate students. Ferroelasticity, twinning and related microstructures are described. Landau-type theories of phase transitions are introduced, togethe…
The electrical characteristics of thermally evaporated triclinic lead phthalocyanine thin films are studied. A number of parameters is evaluated on the basis of the theory of space-charge-limited conduction and the following values are obtained: permittivity ϵ = 3.16 × 10−11 F m−1; hole mobility μ ≈ 6.05 × 10−10 m2 V−…
As judged by the difference between Curie temperature Tc and Curie-Weiss temperature Θ (Tc−Θ∼53 °C) KNbO3 goes through a very strongly first-order phase change at Tc into a tetragonal ferroelectric phase. For BaTiO3, it is known that the weaker first-order change at Tc (Tc−Θ∼10 °C) derives from the electrostrictive co…