308 research outputs found
Three-dimensional microstructuring of yttrium aluminum garnet crystals for laser active optofluidic applications
The following article appeared in Applied Physics Letters 103.4 (2013): 041101 and may be found at http://scitation.aip.org/content/aip/journal/apl/103/4/10.1063/1.4816338We demonstrate three-dimensional microstructuring in a neodymium doped yttrium aluminum garnet (Nd:YAG) crystal. Spatially well-defined hollow microstructures deeply embedded within the material are shown to result from the creation of a pre-damage state within the Nd:YAG crystal network that is validated using luminescence and Raman analyses of the structures. This opens up the potential of fabricating next-generation optofluidic devices in optical gain materialsFinancial support from the Spanish Ministerio de Educación under the Programa de Movilidad de Recursos Humanos del Plan Nacional de IþDþi 2008/2011 for abroad postdoctoral researchers. This work was also supported by the Universidad Autónoma de Madrid and Comunidad Autónoma de Madrid (Project S2009/MAT- 1756) and by the Spanish Ministerio de Educación y Ciencia (MAT2010-16161
High-precision analysis of binary stars with planets. I. Searching for condensation temperature trends in the HD 106515 system
We explore the probable chemical signature of planet formation in the
remarkable binary system HD 106515. The A star hosts a massive long-period
planet with 9 MJup detected by radial velocity. We also refine stellar and
planetary parameters by using non-solar-scaled opacities when modeling the
stars. Methods. We carried out a simultaneous determination of stellar
parameters and abundances, by applying for the first time non-solar-scaled
opacities in this binary system, in order to reach the highest possible
precision. Results. The stars A and B in the binary system HD 106515 do not
seem to be depleted in refractory elements, which is different when comparing
the Sun with solar-twins. Then, the terrestrial planet formation would have
been less efficient in the stars of this binary system. Together with HD
80606/7, this is the second binary system which does not seem to present a
(terrestrial) signature of planet formation, and hosting both systems an
eccentric giant planet. This is in agreement with numerical simulations, where
the early dynamical evolution of eccentric giant planets clear out most of the
possible terrestrial planets in the inner zone. We refined the stellar mass,
radius and age for both stars and found a notable difference of 78% in R
compared to previous works. We also refined the planet mass to mp sini = 9.08
+/- 0.20 MJup, which differs by 6% compared with literature. In addition, we
showed that the non-solar-scaled solution is not compatible with the classical
solar-scaled method, and some abundance differences are comparable to NLTE or
GCE effects specially when using the Sun as reference. Then, we encourage the
use of non-solar-scaled opacities in high-precision studies such as the
detection of Tc trends.[abridged]Comment: 9 pages, 10 figures, A&A accepted. arXiv admin note: text overlap
with arXiv:1507.0812
Creación de un modelo matemático para estimación de precio a partir de regresión múltiple, con aplicación en software, para servicio de control centralizado
164 p.La optimización en las empresas es un paso muy necesario, gracias a esto se producen importantes mejoras ya sea a nivel de procesos, tiempo o calidad. En esta memoria se pretende realizar optimización a un proceso que en la actualidad no está permitiendo abarcar el mercado objetivo, lo cual no permite alcanzar el crecimiento esperado. La consecuencia de ello es baja adjudicación de proyectos, lo cual ha llevado a los encargados a buscar novedosos sistemas de optimización donde es primordial que involucre bajos costos.
La empresa en cuestión es Cam Chile S.A y el área en la cual se necesita la optimización es el servicio de control centralizado, el cual consta de realizar automatización de los sistemas de un edificio y gestión de la energía.
El problema de esta empresa en específico es la gran demora en la entrega de la cotización inicial, que la ha llevado a no ser considerada en las negociaciones posteriores, de esta forma optimizar el tiempo en la entrega de una cotización representa una importante ventaja competitiva, es por esto, que la empresa ha solicitado la creación de un modelo capaz de predecir aproximadamente el precio de futuros proyectos a partir de datos históricos de proyectos ya ejecutados. La elección de realizar un modelo radica en dos criterios, los bajos costos que implica y que no es necesario que el valor sea exacto.
En cuanto al desarrollo se pretenderá encontrar el mejor modelo para los datos basándose en la teoría de la estadística, para que una vez que se obtenga el modelo sea implementado en alguna aplicación para computador y así utilizarlo de forma rápida y fácil
All-optical thermal microscopy of laser-excited waveguides
We report on a unique combination of high-resolution confocal microscopy and ratiometric luminescence thermometry to obtain thermal images of 800 nm pumped ultrafast laser-inscribed waveguides in a Nd:YAG crystal. Thermal images evidence a strong localization of thermal load in the waveguide active volume. Comparison between experimental data and numerical simulations reveals that ultrafast laser-inscribed damage tracks in Nd:YAG crystals behave both as low-index and low-thermal conductivity barriersThis work was supported by the Spanish Ministerio de Economía y Competitividad (MINECO) under grants MAT2013-47395-C4-1-R and FIS2013-44174-P and from Junta de Castilla y León (Project SA116U13, UIC016
Two-photon luminescence thermometry: towards 3D high-resolution thermal imaging of waveguides
We report on the use of the Erbium-based luminescence thermometry to realize high resolution, three dimensional (3D) thermal imaging of optical waveguides. Proof of concept is demonstrated in a 980-nm laser pumped ultrafast laser inscribed waveguide in Er:Yb phosphate glass. Multi-photon microscopy images revealed the existence of well confined intra-waveguide temperature increments as large as 200°C for moderate 980-nm pump powers of 120 mW. Numerical simulations and experimental data reveal that thermal loading can be substantially reduced if pump events are separated more than the characteristic thermal time that for the waveguides investigated is in the millisecond time scaleThis work has been supported by the Ministerio de Economía y Competitividad of Spain (MINECO) (FIS2013-44174-P, MAT2013-47395-C4-1-R) and National Natural Science Foundation of China (NSFC) (11274203
Infrared-Emitting QDs for Thermal Therapy with Real-Time Subcutaneous Temperature Feedback
Nowadays, one of the most exciting applications of nanotechnology in biomedicine is the development of localized, noninvasive therapies for diverse diseases, such as cancer. Among them, nanoparticle-based photothermal therapy (PTT), which destroys malignant cells by delivering heat upon optical excitation of nanoprobes injected into a living specimen, is emerging with great potential. Two main milestones that must be reached for PTT to become a viable clinical treatment are deep penetration of the triggering optical excitation and real-time accurate temperature monitoring of the ongoing therapy, which constitutes a critical factor to minimize collateral damage. In this work, a yet unexplored capability of near-infrared emitting semiconductor nanocrystals (quantum dots, QDs) is demonstrated. Temperature self-monitored QD-based PTT is presented for the first time using PbS/CdS/ZnS QDs emitting in the second biological window. These QDs are capable of acting, simultaneously, as photothermal agents (heaters) and high-resolution fluorescent thermal sensors, making it possible to achieve full control over the intratumoral temperature increment during PTT. The differences observed between intratumoral and surface temperatures in this comprehensive investigation, through different irradiation conditions, highlight the need for real-time control of the intratumoral temperature that allows for a dynamic adjustment of the treatment conditions in order to maximize the efficacy of the therapyThis project has been supported by the Spanish Ministerio de Economía y Competitividad under project and MAT2013-47395-C4-1-R. B. del Rosal thanks Universidad Autónoma de Madrid for an FPI grant. F. Ren acknowledges scholarship support from the Fonds de recherche du Québec – Nature et technologies (FRQNT) under the Programme de Bourses d’Excellence (Merit Scholarship Program for Foreign Students
Anisotropic lattice changes in femtosecond laser inscribed Nd3+:MgO:LiNbO3 optical waveguides
We report on the fabrication and microspectroscopy imaging of femtosecond laser written
double-filament based Nd3+ :MgO:LiNbO3 optical waveguides. The waveguiding high
refractive-index regions are identified by blueshifts of the Nd3+ ion fluorescence lines with no
deterioration in the fluorescence efficiency, whereas filamentary low-index regions are identified by
both a Nd3+ line redshift and a fluorescence efficiency reduction. The lattice structural
micromodifications at the origin of both waveguide formation and Nd3+ fluorescence changes have
been investigated by means of confocal micro-Raman experiments. We have found that the direct
laser written filaments are mainly constituted by a large density of defects, together with a marked
axial compression perpendicular to the filaments �along the optical c-axis�. Conversely, the
high-index waveguiding regions are characterized by a pronounced anisotropic dilatation of the
LiNbO3 lattice xy-planes
Low X-Ray Luminosity Galaxy Clusters: Main goals, sample selection, photometric and spectroscopic observations
We present the study of nineteen low X-ray luminosity galaxy clusters (L 0.5--45 erg s), selected from the ROSAT
Position Sensitive Proportional Counters (PSPC) Pointed Observations (Vikhlinin
et al. 1998) and the revised version of Mullis et al. (2003) in the redshift
range of 0.16 to 0.7. This is the introductory paper of a series presenting the
sample selection, photometric and spectroscopic observations and data
reduction. Photometric data in different passbands were taken for eight galaxy
clusters at Las Campanas Observatory; three clusters at Cerro Tololo
Interamerican Observatory; and eight clusters at the Gemini Observatory.
Spectroscopic data were collected for only four galaxy clusters using Gemini
telescopes. With the photometry, the galaxies were defined based on the
star-galaxy separation taking into account photometric parameters. For each
galaxy cluster, the catalogues contain the PSF and aperture magnitudes of
galaxies within the 90\% completeness limit. They are used together with
structural parameters to study the galaxy morphology and to estimate
photometric redshifts. With the spectroscopy, the derived galaxy velocity
dispersion of our clusters ranged from 507 km~s for [VMF98]022 to 775
km~s for [VMF98]097 with signs of substructure. Cluster membership has
been extensively discussed taking into account spectroscopic and photometric
redshift estimates. In this sense, members are the galaxies within a projected
radius of 0.75 Mpc from the X-ray mission peak and with cluster centric
velocities smaller than the cluster velocity dispersion or 6000 km~s,
respectively. These results will be used in forthcoming papers to study, among
the main topics, the red cluster sequence, blue cloud and green populations;
the galaxy luminosity function and cluster dynamics.Comment: 13 pages, 6 tables, 9 figures. Uses emulateapj. Accepted for
publication in The Astronomical Journal. Some formatting errors fixe
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