45 research outputs found

    The heart of a convex body

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    We investigate some basic properties of the {\it heart} ♡(K)\heartsuit(\mathcal{K}) of a convex set K.\mathcal{K}. It is a subset of K,\mathcal{K}, whose definition is based on mirror reflections of euclidean space, and is a non-local object. The main motivation of our interest for ♡(K)\heartsuit(\mathcal{K}) is that this gives an estimate of the location of the hot spot in a convex heat conductor with boundary temperature grounded at zero. Here, we investigate on the relation between ♡(K)\heartsuit(\mathcal{K}) and the mirror symmetries of K;\mathcal{K}; we show that ♡(K)\heartsuit(\mathcal{K}) contains many (geometrically and phisically) relevant points of K;\mathcal{K}; we prove a simple geometrical lower estimate for the diameter of ♡(K);\heartsuit(\mathcal{K}); we also prove an upper estimate for the area of ♡(K),\heartsuit(\mathcal{K}), when K\mathcal{K} is a triangle.Comment: 15 pages, 3 figures. appears as "Geometric Properties for Parabolic and Elliptic PDE's", Springer INdAM Series Volume 2, 2013, pp 49-6

    One Pot Grafting of Tetrairon(III) Single Molecule Magnets on Silicon

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    Herein we report on the Si grafting of two Fe4 derivatives, [Fe4(Li)2(tmhd)6], in which tmhd is 2,2,6,6-tetramethylheptane-3,5-dionate and H3Li = R–C(CH2OH)3 is a tripodal ligand with R = CH2=CH–CH2–O–CH2 (H3L1) and CH2=CH–(CH2)9–O–CH2 (H3L2). These complexes were specifically designed to be directlyanchored on the H-terminated silicon surface via the hydrosilylation reaction. The complexes were grafted by a one pot route based on the photoinduced hydrosilylation followed by a ligand exchange step in the same reaction solution. The resulting decorated surfaces were characterized using X-ray photoelectronspectroscopy (XPS), attenuated total reflection infrared spectroscopy (ATR-IR) and atomic force microscopy (AFM)
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