Materials Literature
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Prolonged exposure to X-rays of HAuCl(4) deposited from an aqueous solution onto a SiO(2)/Si substrate or into a poly(methyl methacrylate) (PMMA) matrix induces reduction of the Au(3+) ions to Au(0) and subsequent nucleation to gold nanoclusters as recorded by X-ray photoelectron spectroscopy. The corresponding major…
A rather simple yet effective way to fabricate gradient surfaces by changing polystyrene (PS) microsphere topography in a temperature gradient field is proposed. The wettability of the film has an obvious gradient change from 88.7 to 148.1 degrees . The changes of the PS microsphere topography are believed to be respo…
Carbonate-assisted hydrolysis of Y or Yb(III) ions in the presence of the trivacant Wells-Dawson polyoxoanion, alpha-[P(2)W(15)O(56)](12-), produced two polyoxometalate-supported Y- or Yb(III)-hydroxo/oxo clusters, which have been characterized by single-crystal X-ray structure determination. The structure of the Y co…
The challenge of designing solid state compounds with predicted compositions and structures could be partly met using concepts that employ phase homologies. Homologous series of compounds not only can place seemingly diverse phases into a single context; they can also forecast with high probability specific new phases…
The local atomic disorder and the electronic structure in the environment of manganese atoms in LaMnO_3 has been studied by x-ray absorption spectroscopy, over a temperature range (300K to 870K) covering the orbital ordering transition (710K). The Mn-O distances splitting into short and long bonds (1.95 and 2.15A) is…
We have examined the local structure of $\mathrm{Pb}{\mathrm{Mg}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ (PMN-PT) and $\mathrm{Pb}{\mathrm{Zn}}_{1∕3}{\mathrm{Nb}}_{2∕3}{\mathrm{O}}_{3}\mathrm{Pb}\mathrm{Ti}{\mathrm{O}}_{3}$ (PZN-PT) solid solutions using density functional th…
Monatomic nanowires of the nonmagnetic transition metals Ru, Rh, and Pd have been studied theoretically, using first-principles computational techniques, in order to investigate the possible onset of magnetism in these nanosystems. Our fully relativistic spin-polarized all-electron density functional calculations reve…
Loss of braking power and rubber skidding on a wet road is still an open physics problem, since neither the hydrodynamical effects nor the loss of surface adhesion that are sometimes blamed really manage to explain the 20-30% observed loss of low speed tire-road friction. Here we advance a novel mechanism based on sea…
A time-resolved analysis of the amplitude and phase of THz pulses propagating through three-dimensional photonic crystals is presented. Single-cycle pulses of THz radiation allow measurements over a wide frequency range, spanning more than an octave below, at and above the bandgap of strongly dispersive photonic cryst…
Infrared absorbance measurements have been carried out on two liquid crystalline organo-siloxane tetrapodes. Results unambiguously show the existence of a biaxial nematic phase below a uniaxial nematic phase. The three components of IR absorbance are used to calculate the various order parameters. On cooling, a weak f…
Direct atomic resolution images have been obtained that illustrate how a range of rare-earth atoms bond to the interface between the intergranular phase and the matrix grains in an advanced silicon nitride ceramic. It has been found that each rare-earth atom bonds to the interface at a different location, depending on…
In this paper, we present a new method for rapid synthesis of high quantum yield CdTe nanocrystals in the aqueous phase by microwave irradiation with controllable temperature.
The modeling of vector behavior of magnetic materials is an open research topic, it is used in a large number of different applications. Several models have been proposed, these must satisfy two physical properties: saturation and loss. This paper introduces a new vector Preisach hysteresis model that, differently by…
Abstract An attempt was made to prepare nanographite with uniform size by pyrolysis of 4‐methyl pyridine (MPy), which is the structure‐directing agent for the formation of GaPO 4 ‐LTA single crystals, in the GaPO 4 ‐LTA framework at 760°C. The as‐prepared nanographite has been examined by Raman spectroscopy, transmiss…
Spin reorientation effects in DyFe12–xNbx compounds with x=0.6, 0.7 and 0.8 have been investigated by ac magnetic susceptibility and 57Fe Mössbauer effect measurements over the temperature range 4.2–300 K. Refinements of the X-ray diffraction patterns show that DyFe12–xNbx compounds crystallize in the ThMn12-type stru…
Abstract The influence of the addition of poly(methyl methacrylate)- block polystyrene (PMMA- b -PS) and PS- b -poly(n-butyl acrylate) (PS- b -PnBA) diblock copolymers on the structure and the mechanical properties of PMMA/PnBA polymer blends was investigated. In binary polymer blends of PMMA and PS, and PS and PnBA,…
The effect of an external magnetic field directed along various symmetry axes of a crystal on Jahn-Teller-type structural phase transitions (quadrupole ordering) is studied in YbPO 4 and YbVO 4 crystals with zircon structure. In the absence of a magnetic field, the crystals are in a precritical state and do not exhibi…
Abstract Molecular dynamics in selected novel linear/low-branched polyurethanes (PUs), based on oligo(oxytetramethylene glycol), 4,4'-diphenylmethanediisocyanate (MDI) or 2,6-toluenediisocyanate (TDI), and unsymmetrical dimethylhydrazine (I) and a derivative of that (II) as chain extenders (CE), were studied by dielec…
Abstract The effect of the addition of hydrocarbon oil on the mechanical behaviour of isotactic polypropylenes (iPPs) was examined. It was found that the oil molecules are completely dissolved in the amorphous region of iPP so that the blending lowers the glass transition temperature, T g , of iPP. As a result, Young’…
The influence of process variables on characteristics of modal siro-spun yarns has been studied using Box-Behnken response surface design. The characteristics of these yarns have been evaluated and compared with those of equivalent double-rove spun yarns. I t i s observed that the increase in strand spacing from 6 mm…