Microcrystalline silicon: Strain gauge and sensor arrays on flexible substrate for the measurement of high deformations

International audienceThis paper presents strain sensor arrays on flexible substrates able to measure local deformation induced by radii of curvature of few millimeters. Sensors use n-type doped microcrystalline silicon (μc-Si) as piezoresistive material, directly deposited on polyimide sheets at 165 °C. Sensitivity of individual sensors was investigated under tensile and compressive bending at various radii of curvature, down to 5 mm. A Transmission Line Method was used to extract the resistivity for each radius. The devices exhibited longitudinal gauge factors of −31 and longitudinal piezoresistive coefficients of −4.10−10 Pa−1. Reliability was demonstrated with almost unchanged resistances after cycles of bending (standard deviation of 1.7%). Strain gauge arrays, composed of 800 resistors on a 2 cm2 area, were fabricated with a spatial resolution of 500 × 500 μm2. Strain mapping showed the possibility to detect local deformation on a single resistor or to detect larger objects. These strain sensor arrays can find applications when high sensitivity and high spatial resolution is required. This paper also showed that μc-Si can be a relevant semi-conductor candidate for flexible electronic

Silicon deformation sensors fabricated directly on flexible substrate

International audienc

Silicon: A flexible material for bendable electronics and sensors

International audienceDirectly crystallized deposited silicon at low temperature is shown to be the right material when bendable system including treatment electronics and sensing functions is needed. This is true particularly when process reproducibility, electrical and mechanical reliability of the devices are the most important parameters implying the success of the technology. Indeed, these parameters are the main issues when we need to go beyond the publication of a paper, towards actual commercial application. Electrical and mechanical performances of microcrystalline silicon thin film transistors and deformation sensors on 25 μm thick flexible plastics under high bending, still 0.75 mm curvature radius, are presented. These devices are fabricated directly on this substrate at a maximum temperature of 180°C. © 2016 IEEE

Highly resilient crystalised silicon for flexible sensors and electronic devices

International audienc

Highly resilient crystalised silicon for flexible sensors and electronic devices

International audienc

Jano y las caras opuestas de los derechos humanos de los pueblos indígenas

Este libro busca presentar a la comunidad académica nacional e internacional uno de los productos del trabajo de investigación del Observatorio de Redes y Acción Colectiva (ORAC) en su línea de trabajo sobre procesos transnacionales y derechos de los pueblos indígenas. Sus páginas ponen a disposición del lector un conocimiento sustantivo, fundado en investigaciones sociales, sobre la participación de representantes indígenas y especialistas en derecho de los pueblos indígenas en la promoción de causas relativas a los derechos humanos de estos pueblos. En la primera parte del volumen se presenta el proceso de internacionalización del campo de los derechos de los pueblos indígenas. La segunda parte, dedicada al análisis de los estudios de casos: estudia las principales características del proceso de defensa de los derechos humanos de los pueblos indígenas, sus posibilidades y obstáculos

Early diabetes and abnormal postnatal pancreatic islet development in mice lacking Glut-2.

Glut-2 is a low-affinity transporter present in the plasma membrane of pancreatic beta-cells, hepatocytes and intestine and kidney absorptive epithelial cells of mice. In beta-cells, Glut-2 has been proposed to be active in the control of glucose-stimulated insulin secretion (GSIS; ref. 2), and its expression is strongly reduced in glucose-unresponsive islets from different animal models of diabetes. However, recent investigations have yielded conflicting data on the possible role of Glut-2 in GSIS. Whereas some reports have supported a specific role for Glut-2 (refs 5,6), others have suggested that GSIS could proceed normally even in the presence of low or almost undetectable levels of this transporter. Here we show that homozygous, but not heterozygous, mice deficient in Glut-2 are hyperglycaemic and relatively hypo-insulinaemic and have elevated plasma levels of glucagon, free fatty acids and beta-hydroxybutyrate. In vivo, their glucose tolerance is abnormal. In vitro, beta-cells display loss of control of insulin gene expression by glucose and impaired GSIS with a loss of first phase but preserved second phase of secretion, while the secretory response to non-glucidic nutrients or to D-glyceraldehyde is normal. This is accompanied by alterations in the postnatal development of pancreatic islets, evidenced by an inversion of the alpha- to beta-cell ratio. Glut-2 is thus required to maintain normal glucose homeostasis and normal function and development of the endocrine pancreas. Its absence leads to symptoms characteristic of non-insulin-dependent diabetes mellitus