Investigations on some amino acid based single crystals for nonlinear optical applications and amino acid capped nanocrystals

Organic crystals possess extremely large optical nonlinearity compared to inorganic crystals. Also organic compounds have the amenability for synthesis and scope for introducing desirable characteristics by inclusions. A wide variety of organic materials having electron donor and acceptor groups, generate high order of nonlinearity. In the present work, a new nonlinear optical crystal, L-citrulline oxalate (LCO) based on the aminoacid L-citrulline was grown using slow evaporation technique. Structural characterization was carried out by single crystal XRD. It crystallizes in the noncentrosymmetric, orthorhombic structure with space group P21 P21 P21. Functional groups present in the sample were identified by Fourier transform infra red (FTIR) and FT-Raman spectral analysis. On studying the FTIR and Raman spectra of the precursors L-citrulline and oxalic acid, used for growing L-citrulline oxalate crystal, it is found that the significant peaks of the precursors are present in the spectra of the L-citrulline oxalate crystal . This observation along with the presence of NH3 + group in the spectra of L-citrulline oxalate, confirms the formation of the charge transfer complex

Investigations on novel polymer nano composites and bio-compatible manganese doped ZnS nanocrystals for photonic and bio-imaging applications

Fluorescence is a powerful tool in biological research, the relevance of which relies greatly on the availability of sensitive and selective fluorescent probes. Nanometer sized fluorescent semiconductor materials have attracted considerable attention in recent years due to the high luminescence intensity, low photobleaching, large Stokes’ shift and high photochemical stability. The optical and spectroscopic features of nanoparticles make them very convincing alternatives to traditional fluorophores in a range of applications. Efficient surface capping agents make these nanocrystals bio-compatible. They can provide a novel platform on which many biomolecules such as DNA, RNA and proteins can be covalently linked. In the second phase of the present work, bio-compatible, fluorescent, manganese doped ZnS (ZnS:Mn) nanocrystals suitable for bioimaging applications have been developed and their cytocompatibility has been assessed. Functionalization of ZnS:Mn nanocrystals by safe materials results in considerable reduction of toxicity and allows conjugation with specific biomolecules. The highly fluorescent, bio-compatible and water- dispersible ZnS:Mn nanocrystals are found to be ideal fluorescent probes for biological labeling

Studies on the optical band gap and cluster size of the polyaniline thin films irradiated with swift heavy Si ions

Polyaniline thin films prepared by RF plasma polymerisation were irradiated with 92MeV Si ions for various fluences of 1 1011, 1 1012 and 1 1013 ions/cm2. FTIR and UV–vis–NIR measurements were carried out on the pristine and Si ion irradiated polyaniline thin films for structural evaluation and optical band gap determination. The effect of swift heavy ions on the structural and optical properties of plasma-polymerised aniline thin film is investigated. Their properties are compared with that of the pristine sample. The FTIR spectrum indicates that the structure of the irradiated sample is altered. The optical studies show that the band gap of irradiated thin film has been considerably modified. This has been attributed to the rearrangement in the ring structure and the formation of CRC terminals. This results in extended conjugated structure causing reduction in optical band gap

The Effect of Periodic Silane Burst on the Properties of GaN on Si (111) Substrates

The periodic silane burst technique was employed during metalorganic chemical vapor deposition of epitaxial GaN on AlN buffer layers grown on Si (111). Periodic silicon delta doping during growth of both the AlN and GaN layers led to growth of GaN films with decreased tensile stresses and decreased threading dislocation densities, as well as films with improved quality as indicated by x-ray diffraction, micro-Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. The possible mechanism of the reduction of tensile stress and the dislocation density is discussed in the paper.

Effects of Platinum on NiPtSiGe/n-SiGe and NiPtSi/n-Si Schottky Contacts

Solid phase reaction of NiPt/Si and NiPt/SiGe is one of the key issues for silicide (germanosilicide) technology. Especially, the NiPtSiGe, in which four elements are involved, is a very complex system. As a result, a detailed study is necessary for the interfacial reaction between NiPt alloy film and SiGe substrate. Besides using traditional material characterization techniques, characterization of Schottky diode is a good measure to detect the interface imperfections or defects, which are not easy to be found on large area blanket samples. The I-V characteristics of 10nm Ni(Pt=0, 5, 10 at.%) germanosilicides/n-Si₀/₇Ge₀.₃ and silicides/n-Si contact annealed at 400 and 500°C were studied. For Schottky contact on n-Si, with the addition of Pt in the Ni(Pt) alloy, the Schottky barrier height (SBH) increases greatly. With the inclusion of a 10% Pt, SBH increases ~0.13 eV. However, for the Schottky contacts on SiGe, with the addition of 10% Pt, the increase of SBH is only ~0.04eV. This is explained by pinning of the Fermi level. The forward I-V characteristics of 10nm Ni(Pt=0, 5, 10 at.%)SiGe/SiGe contacts annealed at 400°C were investigated in the temperature range from 93 to 300K. At higher temperature (>253K) and larger bias at low temperature (<253K), the I-V curves can be well explained by a thermionic emission model. At lower temperature, excess currents at lower forward bias region occur, which can be explained by recombination/generation or patches due to inhomogenity of SBH with pinch-off model or a combination of the above mechanisms.

Poly-Si₁₋xGex Film Growth for Ni Germanosilicided Metal Gate

Scaling down of the CMOS technology requires thinner gate dielectric to maintain high performance. However, due to the depletion of poly-Si gate, it is difficult to reduce the gate thickness further especially for sub-65 nm CMOS generation. Fully silicidation metal gate (FUSI) is one of the most promising solutions. Furthermore, FUSI metal gate reduces gate-line sheet resistance, prevents boron penetration to channels, and has good process compatibility with high-k gate dielectric. Poly-SiGe gate technology is another solution because of its enhancement of boron activation and compatibility with the conventional CMOS process. Combination of these two technologies for the formation of fully germanosilicided metal gate makes the approach very attractive. In this paper, the deposition of undoped Poly-Si₁₋xGex (0 < x < 30% ) films onto SiO₂ in a low pressure chemical vapor deposition (LPCVD) system is described. Detailed growth conditions and the characterization of the grown films are presented.

Si sois padres... os puede interesar.

Dentro del Plan Municipal sobre drogodependencias del Ayuntamiento de Gijón se editó este folleto que aporta ideas para la reflexión sobre la tarea educativa de la familia, así como alguna estrategia sencilla para afrontar con más facilidad ciertas situaciones que preocupan habitualmente a los padres. Partiendo de situaciones reales se repasan aspectos como la comunicación padres e hijos, la potenciación de la toma de decisiones, la asunción de responsabilidades, el valor del ocio y como cubrirlo, la prevención, la influencia del modelo más cercano, etc. Finalmente se ofrecen direcciones de equipos de coordinación u orientación sobre toxicomanías, centros sociales y centros de salud mental del concejo de Gijón.

Storytelling : cosas que no se olvidan... si aprendemos a contarlas

Este libro es fruto del itinerario formativo en ingl??s previsto para el profesorado de educaci??n infantil. Las autoras, coordinadas por la asesora de Lenguas Extranjeras del CPR de Gij??n, participaron en las fases formativas iniciadas en 2005 con un curso intensivo de Lengua inglesa en el CPR de Gij??n y finalizado en el curso de English-in-York en el Reino Unido. En la ??ltima fase de este itinerario formativo han creado estos materiales sobre varias historias inventadas para ser contadas y para ser explotadas pedag??gicamente en infantil y primer ciclo de primaria. Los objetivos de este material son promover el desarrollo de la expresi??n y comprensi??n oral, aprovechar las t??cnicas narrativas para fomentar la creatividad y madurez del alumnado y usar destrezas y t??cnicas variadas desde un enfoque constructivista. Los temas abordados son: 1) Elaboraci??n de unidades did??cticas de ingl??s en educaci??n infantil. 2) Little Pumpkin and the Halloween Party. 3) Whitie's Trip. 4) The Proud Rainbow. En la primera parte se explica el proceso de dise??o, desarrollo y evaluaci??n de una unidad did??ctica. En las dem??s, se incluyen actividades, juegos, rimas, cuentos, canciones y juegos ilustrados y disponibles para su uso escolar.

Si Aristóteles levantara la cabeza.

Resumen basado en el de la publicación

El proceso de convergencia europea : ocasi??n de modernizar la universidad espa??ola si se produce un cambio de mentalidad en gestores, profesores y estudiantes

Resumen tomado de la publicaci??n

Si hoy puedo ser t??, ma??ana te comprender?? mejor : una experiencia escolar de acercamiento a la discapacidad visual

Resumen en ingl??s y castellano

El català, llengua d'ensenyament. Si s' aspira a fer durar el bilingüisme, és necessari fer tot l'ensenyament en català. 'El catalán, lengua de enseñanza. Si se aspira a hacer durar el bilinguismo, es necesario hacer toda la enseñanza en catalán'.

Resumen tomado de la revista. Ponencia presentada en las Jornadas La normalització lingüística a l'ensenyament i a l'àmbit sindical, que tuvieron lugar en la sala de actos del edificio Anselm Turmeda del campus de la Universitat de les Illes Balears los días 3 y 4 de octubre de 2002

Dialoga amb els i les adolescents per a una major qualitat de la comunicació en el si de la família. 'Dialoga con los y las adolescentes para una mayor calidad de la comunicación en el seno de la familia'.

El presente material se dirige a padres, tutores y educadores. Resumen tomado del propio recurso