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A robust and facile method has been developed to obtain directional growth of silica nanowires (SiO(2)NWs) by regulating mass transport of silicon monoxide (SiO) vapor. SiO(2)NWs are grown by vapor-liquid-solid (VLS) process on a surface of gold-covered spherical photonic crystals (SPCs) annealed at high temperature in an inert gas atmosphere in the vicinity of a SiO source. The SPCs are prepared from droplet confined colloidal self-assembly. SiO2NW morphology is governed by diffusion-reaction process of SiO vapor, whereby directional growth of SiO(2)NWs toward the low SiO concentration is obtained at locations with a high SiO concentration gradient, while random growth is observed at locations with a low SiO concentration gradient. Growth of NWs parallel to the supporting substrate surface is of great importance for various applications, and this is the first demonstration of surface-parallel growth by controlling mass transport. This controllable NW morphology enables production of SPCs covered with a large number of NWs, showing multilevel micro-nano feature and high specific surface area for potential applications in superwetting surfaces, oil/water separation, microreactors, and scaffolds. In addition, the controllable photonic stop band properties of this hybrid structure of SPCs enable the potential applications in photocatalysis, sensing, and light harvesting.

[EN]: Bi2AE2Co2Ox (AE = Ca, Sr, and Ba) thermoelectric compounds were grown from the melt by the laser floating zone technique. Microstructural analysis of as-grown samples has shown the formation of well-aligned thermoelectric grains together with a relative high amount of secondary phases. On the other hand, a short (24 h) thermal treatment (810 °C for Sr, 800 °C for Ca, and 750 °C for Ba) under air, raises of thermoelectric phase content through the recombination of the secondary ones. These microstructural modifications led to a large decrease of electrical resistivity, improving the power factor. These results have been compared with samples prepared by the conventional solid state method and with the best values reported in the literature. From these data, it is possible to deduce that the high thermoelectric characteristics obtained in these samples make them very attractive for practical applications., [ES]: Se han crecido materiales termoeléctricos de la familia Bi2AE2Co2Ox (AE = Ca, Sr y Ba) mediante la técnica de fusión zonal flotante inducida por láser. Los estudios microestructurales han revelado que las muestras crecidas están formadas por granos termoeléctricos bien alineados, acompañados de cantidades apreciables de fases secundarias. Por otro lado, la cantidad de fase termoeléctrica se ha aumentado mediante cortos (24 h) tratamientos térmicos (810 °C para el Sr, 800 °C para el Ca y 750 °C para el Ba) en aire, por reacción de las fases secundarias. Estas modificaciones microestructurales han originado una reducción de la resistividad eléctrica, mejorando el factor de potencia. Los resultados obtenidos se han comparado con los correspondientes a muestras preparadas mediante un proceso clásico en el estado sólido, así como con los mejores resultados que se pueden encontrar en la bibliografía. Todo ello indica que las muestras obtenidas en este trabajo pueden ser muy atractivas para aplicaciones prácticas., This research has been supported by the Spanish MINECO-FEDER (MAT2013-46505-C3-1-R). The authors wish to thank the Gobierno de Aragón and Fondo Europeo de Desarrollo Regional (Consolidated Research Groups T87 and T12) for financial support and to C. Gallego, and C. Estepa for their technical assistance.

Hypereutectic Al-Co alloys of various Co contents (7–20 weight % (wt.%) Co) were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co) to coarse primary Al9Co2 predominance (20 wt.% Co). Co dissolution in Al far exceeded the negligible equilibrium solubility of Co in Al; however, it was hardly uniform. By increasing the cobalt content, the fraction and coarseness of Al9Co2, the content of Co dissolved in the Al matrix, and the hardness and porosity of the alloy increased. All alloys exhibited similar corrosion behavior in 3.5 wt.% NaCl with high resistance to localized corrosion. Al-7 wt.% Co showed slightly superior corrosion resistance than the other compositions in terms of relatively low corrosion rate, relatively low passivation current density and scarcity of stress corrosion cracking indications. All Al-Co compositions demonstrated substantially higher resistance to localized corrosion than commercially pure Al produced by casting, cold rolling and arc melting. A corrosion mechanism was formulated. Surface films were identified.

International audience; Rods of highly magnetostrictive polycrystalline TbxDy1-xFey materials are elaborated by casting in a cylindrical mould with cooling imposed from the bottom which leads to a fast vertical unidirectional growth. A [1 1 0] orientation is obtained along the axis of the rods parallel to the growth direction. The magnetostrictive properties are remarkable along the rods axis comparable to those of [1 1 1] rods. The saturated magnetostriction measured in a parallel magnetic field is lambda(parallel to) = 1124 x 10(-6) under 0 MPa and increases to 1760 x 10(-6) under a compressive stress of 25 MPa. The pseudolinear variation of the magnetostriction with the internal magnetic field Delta lambda(parallel to)/mu(0)Delta H-int reaches 640 x 10(-6)/0.04 T under 9.9 Mfa. The texture and the good magnetostrictive properties are reproducible.

A computational study of morphological instabilities of a two-dimensional nematic front under directional growth was performed using a Landau-de Gennes type quadrupolar tensor order parameter model for the first-order isotropic/nematic transition of 5CB (pentyl-cyanobiphenyl). A previously derived energy balance, taking anisotropy into account, was utilized to account for latent heat and an imposed morphological gradient in the time-dependent model. Simulations were performed using an initially homeotropic isotropic/nematic interface. Thermal instabilities in both the linear and non-linear regimes were observed and compared to past experimental and theoretical observations. A sharp-interface model for the study of linear morphological instabilities, taking into account additional complexity resulting from liquid crystalline order, was derived. Results from the sharp-interface model were compared to those from full two-dimensional simulation identifying the specific limitations of simplified sharp-interface models for this liquid crystal system. In the nonlinear regime, secondary instabilities were observed to result in the formation of defects, interfacial heterogeneities, and bulk texture dynamics., first revision