排序方式: 共有23条查询结果,搜索用时 15 毫秒
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Dr. Joffrey Pijeat Léo Chaussy Roxanne Simoës Dr. Jacopo Isopi Prof. Dr. Jean-Sébastien Lauret Prof. Dr. Francesco Paolucci Prof. Dr. Massimo Marcaccio Dr. Stéphane Campidelli 《ChemistryOpen》2021,10(10):997-1003
The synthesis of π-extended porphyrins containing anthracenyl moieties still represents an important challenge. Here, we report on the synthesis of a series of unsubstituted naphthyl-, pyrenyl- and anthracenyl-fused zinc porphyrin derivatives. To this aim, meso-substitued porphyrins are synthesized and the fusion of the PAHs (Polycyclic Aromatic Hydrocarbon) on the β-positions are performed through thermally induced dehydro-aromatization. The fused zinc-porphyrin derivatives are fully characterized and their optical absorption and photoluminescence properties are reported. We also demonstrate that zinc can be removed from the porphyrin core, giving rise to pure C, H, N materials. This work constitutes the first step towards the synthesis of the fully-fused tetra-anthracenylporphyrin. 相似文献
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We report the first experimental evidence of nontrivial thermal behavior of the simplest mesoscopic system--a superconducting loop. By measuring the specific heat C of an array of 450,000 noninteracting aluminum loops with very high accuracy of approximately 20 fJ/K, we show that the loops go through a periodic sequence of phase transitions (with a period of an integer number of magnetic flux quanta) as the magnetic flux threading each loop is increased. The transitions are well described by the Ginzburg-Landau theory and are accompanied by discontinuities of C of only several thousands of Boltzmann constants kB. 相似文献
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O. Riou M. Charalambous P. Gandit J. Chaussy P. Lejay W. N. Hardy 《Czechoslovak Journal of Physics》1996,46(3):1219-1220
We report on measurements of the specific heat of μg-size YBCO single crystals very close to the superconducting transition in zero field. Detailed data points are obtained down to reduced temperatures of 10?5. Analysis of the derivative of the specific heat yields the critical exponents in an unambiguous way. α+ is positive ~0.5; α- is negative ~ ?0.3. The value of α+ is consistent with gaussian fluctuations above Tc, however the value of α- is inconsistent with either gaussian fluctuations or the 3DXY model. 相似文献
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O. Bourgeois P. Gandit J. Lesueur A. Sulpice X. Grison J. Chaussy 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(1):75-80
We report transport measurements on Superconductor/Ferromagnet/Superconductor (S/F/S) junctions: Nb/Al/Gd/Al/Nb where gadolinium
(Gd) is a weakly polarized ferromagnet. A sizeable critical current I
c is observed in the I(V) characteristics. This current can be modulated by a weak magnetic field, as expected for a Josephson current. With these
experiments, we establish that superconducting coherent transport survives across a small ferromagnetic layer. The penetration
depth of Cooper pairs in Gd has been measured. An extensive study of the Josephson critical current in temperature for different
thicknesses of magnetic compounds is presented. A comparison of transport measurements with S/N/S junction is given through
measurements made on Nb/Al/Y/Al/Nb, where yttrium (Y) is used as non magnetic rare earth metal.
Received 20 September 2000 and Received in final form 22 February 2001 相似文献
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Davide Beneventi Sabrine Alila Sami Boufi Didier Chaussy Patrice Nortier 《Cellulose (London, England)》2006,13(6):725-734
Polypyrrole was polymerized on the surface of cellulose fibres using a sequence of fibre impregnation in FeCl3 solutions, thickening and re-dispersion in a pyrrole solution. ζ-Potential and adsorption isotherms of the FeCl3-cellulose systems showed that the adsorption of iron III was associated with the formation of free Fe3+ cations in the impregnation liquor. Moreover, under the test conditions applied, the amount of adsorbed iron III was not sufficient to promote the polymerization of a adequate amount of pyrrole on the fibre surface. Optimization of the polymerization reaction required that the FeCl3 concentration in the impregnation liquor be increased to approximately 1 mol/l with a subsequent decrease of pH to approximately1.8. Based on scanning electron (SEM) micrographs and the low cellulose polymerization degree measured after pyrrole polymerization, we concluded that the decrease in the electric resistance of bulky polypyrrole/cellulose compounds was associated with a not negligible degradation of the cellulose fibres due to acid hydrolysis and the subsequent impossibility to prepare hand sheets with modified fibres due to the insufficient strength of the wet fibre network. The results of this investigation bring into question the use of FeCl3-pyrrole-cellulose systems for the elaboration of conducting paper sheets with good and stable mechanical properties. 相似文献
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From general thermodynamical relations we derive the magnetic field expansion of the specific heat for the paramagnetic phase of a spin glass. Experimental results for the magnetocaloric effect of a Mn 0.25 at% allow us to determine the successive terms of this expansion. We reach a precision of several percent for the terms which are as small as 10-3 or 10-4 of the total specific heat. 相似文献
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J. Chaussy P. Haen J.C. Lasjaunias P. Monceau G. Waysand A. Waintal A. Meerschaut P. Molinié J. Rouxel 《Solid State Communications》1976,20(8):759-763
We describe the physical properties of the transition metal trichalcogenide NbSe3 including electrical resistivity, magnetic susceptibility, and heat capacity. NbSe3 undergoes phase transitions at 145 and 59 K. The effect of pressure on these transitions is also reported. We try to explain the physical properties of NbSe3 in terms of the formation of charge density waves. 相似文献
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Lara Jabbour Roberta Bongiovanni Didier Chaussy Claudio Gerbaldi Davide Beneventi 《Cellulose (London, England)》2013,20(4):1523-1545
Li-ion batteries (LIBs) are the most employed power source in portable electronics (e.g., cellular phones, laptop computers…) and are accounted as very promising storage/power systems for future electric/hybrid-electric powered transportation. However for their future development, low production costs and environmental friendliness will be key parameters. In this context, the introduction of water processable biosourced polymers such as cellulose and its derivatives is very interesting and is emerging as a viable route toward the development of green materials and processes for LIB manufacturing. The present review briefly introduces the Li-ion technology and gives an overview on cellulose and cellulose derivatives for the elaboration of separators, electrolytes and electrodes. 相似文献