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Nombre figuré

un nombre entier qui peut être représenté par un ensemble de points disposés de façon plus ou moins régulière et formant une figure géométrique.

On attribue parfois à Pythagore les premières études de nombres figurés[1] (nombres carrés). Diophante a résolu plusieurs problèmes les concernant. Pascal a écrit un traité sur le sujet.

The conversion of sunlight into electricity has been dominated by photovoltaic and solar thermal power generation. Photovoltaic cells are deployed widely, mostly as flat panels, whereas solar thermal electricity generation relying on optical concentrators and mechanical heat engines is only seen in large-scale power plants. Here we demonstrate a promising flat-panel solar thermal to electric power conversion technology based on the Seebeck effect and high thermal concentration, thus enabling wider applications. The developed solar thermoelectric generators (STEGs) achieved a peak efficiency of 4.6% under AM1.5G (1 kW m−2) conditions. The efficiency is 7–8 times higher than the previously reported best value for a flat-panel STEG, and is enabled by the use of high-performance nanostructured thermoelectric materials and spectrally-selective solar absorbers in an innovative design that exploits high thermal concentration in an evacuated environment.

XBee Tutorial: Setting up your XBees

XBees are wireless transceivers from Digi that implement the Zigbee protocol. They are simple devices that we can use to set up serial communications between our applications. Using the XBee tutorial you will have your devices talking in no time!