Materials Literature
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Woven Hi‐Nicalon™‐reinforced melt‐infiltrated SiC‐matrix composites were tested under tensile stress‐rupture conditions in air at intermediate temperatures. A comprehensive examination of the damage state and the fiber properties at failure was performed. Modal acoustic emission analysis was used to monitor damage dur…
Space charge observation is becoming the most widely used technique to evaluate polymeric materials for dc insulation applications, particularly HV cables. However, quantities are still lacking that can help to summarize and interpret the huge amount of data resulting from space charge measurements, and that also are…
A large number of carboxylic groups were introduced onto chitosan by grafting with poly(acrylic acid) as an efficient way of modification. The reactions were carried out in a homogeneous aqueous phase by using potassium persulfate and ferrous ammonium sulfate as the combined redox initiator system. The efficiency of g…
The ac conductivity resulting from ion motion in glasses displays a power-law frequency dependence characterized by an exponent $n<1.$ Recently, it was suggested that this exponent depends upon the dimensionality of the local cation conduction space, such that n decreases with decreasing dimensionality. Here, I rep…
VSiβ zeolites prepared by contacting dealuminated Siβ zeolite with aqueous solutions of ammonium metavanadate at room temperature have been studied by diffuse reflectance UV−visible and photoluminescence spectroscopy. UV−visible spectroscopy shows that whatever the vanadium content, vanadium is present in as-prepared…
This paper reports direct microscopic evidence of magnetoelastic coupling between ferroelastic twin domains and ferromagnetic Weiss domains in magnetic shape memory alloys, using the Ni-Mn-Ga Heusler alloys. In a martensitically transformed ${\mathrm{Ni}}_{2+x}{\mathrm{Mn}}_{1\ensuremath{-}x}\mathrm{Ga}$ single crysta…
The nonlinear oscillations of a spherical, acoustically forced gas bubble in nonlinear viscoelastic media are examined. The constitutive equation [Upper-Convective Maxwell (UCM)] used for the fluid is suitable for study of large-amplitude excursions of the bubble, in contrast to the previous work of the authors which…
Polarized electroluminescence from a uniformly aligned nematic network, formed by photopolymerization of a LC monofluorene with diene end-groups (see Figure), is reported. It is shown that macroscopic orientation of the chromophore is achieved with a photoalignment layer doped to allow hole transport. Thus standard ph…
Macroporous gold has been prepared by impregnating artificial opals using electrodeposition. Both latex and silica spheres were used to prepare the opal templates. The silica spheres could be removed without damage to the patterned gold, which is subsequently an excellent reflection of the original template. The Figur…
Layer-by-layer sequential adsorption (LBL) has been applied to the preparation of composite multilayer thin films of thiol-capped HgTe nanocrystals with strong IR luminescence. The films can be used as active coatings for novel optical sources for telecommunications.
A general and novel method for the controlled synthesis of aliphatic polyesters is presented. The evaluation of stannous (II) trifluoromethane sulfonate [Sn(OTf)2] and scandium (III) trifluoromethane sulfonate [Sc(OTf)3] as catalysts for the ring-opening polymerization (ROP) of various lactones is described as a route…
In the present Letter we demonstrate that particle shape can be controlled even if the macroscopic structure of the self-assembly used as a template remains unchanged. We demonstrate that the control of nanocrystal shape is influenced by the addition of salt while the same template is kept.
The Journal of Phycology was founded in 1965 by the Phycological Society of America. All aspects of basic and applied research on algae are included to provide a common medium for the ecologist, physiologist, cell biologist, molecular biologist, morphologist, oceanographer, taxonomist, geneticist, and biochemist. The…
The novel dimeric silicotungstates [[SiM2W9O34(H2O)]2]12- (M = Mn2+, Cu2+, Zn2+) have been synthesized and characterized by IR spectroscopy, elemental analysis, and magnetic measurements. X-ray single-crystal analyses were carried out on K4Na6Mn[[SiMn2W9O34(H2O)]2].33H2O (1), which crystallizes in the triclinic system…
The frequencies of the softest polar optic phonons of tetragonal SrTiO 3 are accurately determined using high-resolution hyper-Raman spectroscopy on oriented-domain crystals. The splitting of the polar soft mode in the tetragonal phase is quantitatively related to the 105 K structural transition, i.e. , to the rotatio…
We have fabricated spin polarized tunneling devices based upon half-metallic manganites $({\mathrm{La}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3})$ incorporating ${\mathrm{NdGaO}}_{3}$ as a barrier material. These devices show high tunnel magnetoresistance (TMR) values above 77 K and coherent switching with a qualita…
The concept of polarization freedom is employed to design diffraction gratings that are capable of transforming an electromagnetic plane wave into two or three diffraction orders with an arbitrary efficiency distribution among them, such that the combined efficiency of the signal orders is always equal to 100%. As a s…
The electronic structure and chemisorption properties of the surface of ionic crystals are reviewed, with emphasis on two topics: a critical overview of the experimental and theoretical studies of the adsorption of CO on single crystal and polycrystalline MgO, and a discussion on the most important defect centers at t…
De novo adipogenesis at the implanted site of a basement membrane extract (Matrigel) was induced through controlled release of basic fibroblast growth factor (bFGF). bFGF was incorporated into biodegradable gelatin microspheres for its controlled release. When the mixture of Matrigel and bFGF-incorporated gelatin micr…
We have developed an analytical self-consistent-field (SCF) theory describing conformations of weakly charged polyelectrolyte chains tethered to the solid−liquid interface and immersed in a solution of low molecular weight salt. Depending on the density of grafting of the polyelectrolytes to the interface and on the s…