La estructura y propiedades magn��ticos de las nanopart��culas de Fe50Ni50 obtenidas mediante el m��todo de explosi��n el��ctrica de hilo

[Es]Actualmente ninguna ��rea cient��fica es ajena a la revoluci��n de la nanociencia; las nanopart��culas atraen el inter��s de muchos investigadores desde el punto de vista de la ciencia fundamental y para sus aplicaciones tecnol��gicas. Las nanopart��culas ofrecen la posibilidad de fabricar sensores que sean capaces de detectar desde un virus hasta concentraciones de substancias pat��genas que no pueden ser detectadas por los m��todos convencionales. Hoy en d��a existes 82 tratamientos contra el c��ncer basadas en la utilizaci��n de nanopart��culas y los materiales composite con nanopart��culas se utilizan como medio de protecci��n frente la radiaci��n del rango de microondas. En la rama de ciencias ambientales, las nanopart��culas met��licas sirven como materiales anticontaminantes. En este trabajo se ha estudiado la estructura y las propiedades magn��ticas de las nanopart��culas de FeNi preparadas mediante el m��todo de explosi��n el��ctrica de hilo. Con la t��cnica de Rayos���X(DRX) se ha determinado que las nanopart��culas se cristalizan en un sistema c��bico FCC con un par��metro de celda de 3.596 ��, tambi��n, se ha obtenido el tama��o de dominio coherente que es de 35 nm. La muestra se ha sometido a un programa de temperatura controlada para seguir la evoluci��n de la estructura cristalina y del tama��o del cristal, tanto en atm��sfera oxidante como en vac��o. Para el aprendizaje de los microscopios utilizados en este trabajo, se ha asistido al curso ���Fundamentos de microscopia electr��nica de barrido y microan��lisis��� impartido por SGIker de la UPV/EHU. Se han empleado los microscopios electr��nicos SEM y TEM para obtener im��genes de gran resoluci��n de la muestra y analizar su contenido elemental. Partiendo de las im��genes sacadas por el SEM se ha calculado el valor medio del tama��o de las part��culas de la muestra, 58 nm. Mediante el Mastersizer 2000 se ha medido el tama��o de las part��culas y/o agregados por m��todo de difracci��n l��ser, disgregando la muestra todo lo posible hasta conseguir el tama��o medio que se aproxime al de una sola part��cula, 100nm. Por ��ltimo, para la caracterizaci��n magn��tica se ha servido del VSM que mide el momento magn��tico de una muestra cuando ��sta vibra en presencia de un campo magn��tico est��tico, consiguiendo una imanaci��n de saturaci��n de 125 emu/g. Hemos fabricado y caracterizado las nanopart��culas magn��ticas de hierro-n��quel y los resultados obtenidos han sido enviados a un congreso especializado de ciencia de materiales (ISMANAM - 2013, Italia).

Advances in Click Chemistry for Single-Chain Nanoparticle Construction

Single-chain polymeric nanoparticles are artificial folded soft nano-objects of ultra-small size which have recently gained prominence in nanoscience and nanotechnology due to their exceptional and sometimes unique properties. This review focuses on the current state of the investigations of click chemistry techniques for highly-efficient single-chain nanoparticle construction. Additionally, recent progress achieved for the use of well-defined single-chain nanoparticles in some promising fields, such as nanomedicine and catalysis, is highlighted.

Sintesi hidrotermal bidezko titanio dioxidozko nanohodien lorpena

[EUS] Gaur egun nanozientzia zientzia eta teknologia arlo guztietara zabaldu da, gizarte garapenean eragin handia izan du. Ikerkuntza arlo guztietara zabaldu da ezinezkoak ziruditen erronkak argitu eta ezezagunak ditugun ezagutzak garatzeko asmoz. Lan honetan TiO2 nanohagatxoen sintesia burutu da metodo hidrotermala erabiliz. Sintesi baldintzek lortutako produktuaren egituran eta forman duten eragina kontuan harturik, sintesia gertatzeko ezinbestekoak diren pHa, tenperatura eta denbora aztertu dira. Ondoren, tratamendu kimiko eta termiko ezberdinen bidez konposizio eta egitura ezberdinak lor daitezkeela frogatu da. Bereziki, surfaktante eta pHaren arabera egitura ezberdinak lortzen direla ikusirik. Sintetizatutako laginen karakterizazioa burutzeko X izpien difrakzioa, transmisio bidezko mikroskopia elektronikoa, infragorri espektroskopia, eta termograbimetria teknikak erabili dira. Hauen bidez NaTi3O6��(OH)x��(H2O)y , (TiO2)x(H2O)y , anatasa eta rutilo faseak identifikatu dira, eta nanohagatxoen lodiera eta morfologia ezberdinak ikusi dira.

Growth, structural and optical properties of GaAs/AlGaAs Core/shell nanowires with and without quantum well shells

We have investigated the growth, structural properties and photoluminescence of novel GaAs/AlGaAs radial heterostructure nanowires, fabricated by metalorganic chemical vapour deposition. The effect of growth temperature on nanowire morphology is discussed. Strong photoluminescence is observed from GaAs nanowires with AlGaAs shells. Core/multishell nanowires, of GaAs cores clad in several alternating layers of thick AlGaAs barrier shells and thin GaAs quantum well shells, exhibit a blue-shifted photoluminescence peak believed to arise from quantum confinement effects. A novel two-temperature growth procedure for obtaining GaAs cores is introduced, and other nanowire heterostructures are addressed. �� 2006 IEEE.

Understanding the kink formation in GaAs/InAs heterostructural nanowires

The kinks formation in heterostructural nanowires was observed to be dominant when InAs nanowires were grown on GaAs nanowires. Nanowires were grown through vapor-liquid-solid (VLS) mechanism in an MOCVD (metalorganic chemical vapor deposition) reactor. GaAs nanowires were grown in [1 1 1 ]B direction on a GaAs (1 1 1 )B substrate. When InAs nanowires grown on the GaAs nanowires, most of the InAs nanowires changed their growth directions from [1 1 1 ]B to other ���111���B directions. The kinks formation is ascribed to the large compressive misfit strain at the GaAs/InAs interface (7.2% lattice mismatch between GaAs and InAs) and the high mobility of indium species during MOCVD growth. The in-depth analysis of the kinks formation was done by growing InAs for short times on the GaAs nanowires and characterizing the samples. The hindrance to compressively strain InAs to form coherent layers with GaAs pushed the InAs/Au interfaces to the sides of the GaAs nanowires growth ends. New InAs/Au interfaces have generated at the sides of GaAs nanowires, due to lateral growth of InAs on GaAs nanowires. These new interfaces led the InAs nanowires growth in other ���111���B directions. The morphological and structural features of these heterostructural kinked nanowires were characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. �� 2006 IEEE.

Growth mechanism of truncated triangular GaAs nanowires

During the growth of GaAs nanowires on the {111}B GaAs substrate, truncated triangular GaAs nanowires were commonly observed in the bottom region of nanowires. Through detailed structural analysis by electron microscopy, we have determined the growth mechanism of truncated triangular GaAs nanowires. �� 2006 IEEE.

Electroless-plated gold films for sensitive surface plasmon resonance detection of white spot syndrome virus

The paper describes the rapid and label-free detection of the white spot syndrome virus (WSSV) using a surface plasmon resonance (SPR) device based on gold films prepared by electroless plating. The plating condition for obtaining films suitable for SPR measurements was optimized. Gold nanoparticles adsorbed on glass slides were characterized by transmission electron microscopy (TEM). Detection of the WSSV was performed through the binding between WSSV in solution and the anti-WSSV single chain variable fragment (scFv antibody) preimmobilized onto the sensor surface. Morphologies of the as-prepared gold films, gold films modified with self-assembled alkanethiol monolayers, and films covered with antibody were examined using an atomic force microscope (AFM). To demonstrate the viability of the method for real sample analysis, WSSV of different concentrations present in a shrimp hemolymph matrix was determined upon optimizing the surface density of the antibody molecules. The SPR device based on the electroless-plated gold films is capable of detecting concentration of WSSV as low as 2.5 ng/mL in 2% shrimp hemolymph, which is one to two orders of magnitude lower than the level measurable by enzyme-linked immunosorbant assays. (c) 2007 Elsevier B.V. All rights reserved.