26 research outputs found
DISEÑO Y CONSTRUCCIÓN DE UN SISTEMA DE ELECTRÓLISIS PARA SÍNTESIS DE NANOPARTÍCULAS DE PLATA UTILIZANDO INSTRUMENTACIÓN VIRTUAL CON LABVIEW (DESIGN AND CONSTRUCTION OF AN ELECTROLISIS SYSTEM FOR SILVER NANOPARTICLES SYNTHESIS BY VIRTUAL INSTRUMENTATION)
ResumenActualmente, la nanotecnología está presente en muchos productos que se encuentran en el mercado y cada vez tiene mayor uso en la solución de problemáticas, al ser un área interdisciplinaria, es necesario el trabajo en conjunto de científicos e ingenieros para el desarrollo de tecnologías. Los materiales en una escala nanométrica requieren de sistemas especializados y complejos, dando como resultado variedad de estructuras tales como nanovarillas, nanoalambres, nanocolumnas y nanopartículas, por mencionar algunas. En este trabajo, se presenta un sistema de síntesis de nanopartículas de plata utilizando un multímetro Fluke de doble pantalla (dual display) para medición de corriente, una fuente de voltaje de la marca BK Precision, una tarjeta Arduino como interface e instrumentación virtual con LabVIEW para control de los tiempos de reacción y el tiempo de conmutación de polaridad de los electrodos. En conjunto es un sistema que puede realizar las tareas de adquisición, procesamiento y presentación de datos. Se realizaron dos experimentos de síntesis de NPs, con un tiempo de proceso de 30 minutos, tiempo de conmutación de la polaridad de 5 minutos a 60 °C variando el voltaje aplicado de 5 y 10 V. La obtención de las NPs en los experimentos es demostrada analizando los espectros de absorción UV-Vis de la solución coloidal obtenida. Se obtuvieron NPs con un tamaño promedio de 122 nm para el voltaje de aplicación de 5 V y 106 nm para las NPs sintetizadas con un voltaje de 10 V. La distribución de tamaño fue obtenida utilizando la técnica de Dispersión de Luz Dinámica (DLS, Dynamic Light Scattering). En futuras investigaciones se pretende utilizar las NPs obtenidas con este sistema automático para realizar la síntesis de óxido de zinc dopado con plata (ZnO tipo p), el cual, será utilizado para la fabricación de dispositivos electrónicos como LEDs y celdas solares.Palabras Claves: Nanopartículas, Plata, Electrolisis, Automatizado. AbstractCurrently, nanotechnology is present in many products that are in the market and is increasingly used to solve problems, being an interdisciplinary area, it is necessary the joint work of scientists and engineers for the development of technologies. Materials on a nanometric scale require specialized and complex systems, resulting in a variety of structures such as nanowires, nanowires, nanocolumns and nanoparticles, to name a few. In this work, a system for the synthesis of silver nanoparticles is presented using a dual display Fluke multimeter (dual display) for current measurement, a voltage source of the BK Precision brand, an Arduino card as an interface and virtual instrumentation with LabVIEW for control of reaction times and electrode polarity switching time. Together it is a system that can perform the tasks of acquisition, processing and presentation of data. Two experiments of synthesis of NPs were carried out, with a process time of 30 minutes, polarity switching time of 5 minutes at 60 ° C varying the applied voltage of 5 and 10 V. The formation of NPs in the experiments is demonstrated by analyzing the UV-Vis absorption spectra of the colloidal solution obtained. NPs with an average size of 122 nm were obtained for the application voltage of 5 V and 106 nm for NPs synthesized with a voltage of 10 V. The size distribution was obtained using Dynamic Light scattering. In future research it is intended to use the NPs obtained with this automatic system to perform the synthesis of zinc oxide doped with silver (ZnO type p), which will be used for the manufacture of electronic devices such as LEDs and solar cells.Keywords: Nanoparticles, Silver, Electrolysis, Automated
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
SISTEMA DE DEPÓSITO POR CAPAS ATÓMICAS TÉRMICO PARA LA SÍNTESIS DE PELÍCULAS DELGADAS DE ÓXIDO DE HAFNIO (THERMAL ATOMIC LAYER DEPOSITION SYSTEM FOR THE SYNTHESIS OF HAFNIUM OXIDE THIN FILMS)
Resumen
El depósito por capas atómicas (ALD, Atomic Layer Deposition) es un proceso de fabricación de películas delgadas que ha mantenido su relevancia durante los últimos años, impulsando a los laboratorios de nanofabricación a poseer, de forma casi obligatoria, un sistema de depósito atómico.
Por medio del diseño e implementación de un sistema mecatrónico basado en modelado mecánico CAD, instrumentación virtual y automatización, este trabajo presenta un equipo capaz de producir, de forma controlada y reproducible, películas nanométricas de óxido de hafnio utilizando Tetrakis (etilmetilamino) hafnio (IV) y vapor de agua como precursores, y nitrógeno como gas de purga.
Como resultado, las pruebas realizadas al equipo obtenido mostraron un control de la secuencia de depósito configurada desde una interfaz gráfica, un rango de temperatura de 25 a 700 °C, un flujo de nitrógeno entre los 0 y 200 SCCM, y una presión de vacío mínima de 14 mTorr.
Palabras Clave: ALD, Automatización, Óxido de Hafnio, Películas Nanométricas
Abstract
Atomic Layer Deposition (ALD) is an ultrathin film fabrication process that has remained relevant in recent years, prompting nanofabrication laboratories to have an atomic deposition system almost mandatory.
Through the design and implementation of a mechatronic system based on CAD mechanical modeling, virtual instrumentation and automation, this work presents an equipment capable of producing, in a controlled and reproducible way, nanometric hafnium oxide films using Tetrakis (ethylmethylamino) hafnium (IV ) and water vapor as precursors, and nitrogen as purge gas.
As a result, the tests performed on the equipment obtained showed a control of the deposition sequence configured from a graphical interface, a temperature range of 25 to 700 °C, a nitrogen flow between 0 and 200 SCCM, and a minimum vacuum pressure of 14 mTorr.
Keywords: ALD, Automation, Hafnium Oxide, Nanometric Films