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41.
42.
In this paper we specialize the results obtained in [BF1] to the case of a family of Dirac operators. We first calculate the curvature of the unitary connection on the determinant bundle which we introduced in [BF1].We also calculate the odd Chern forms of Quillen for a family of self-adjoint Dirac operators and give a simple proof of certain results of Atiyah-Patodi-Singer on êta invariants.We finally give a heat equation proof of the holonomy theorem, in the form suggested by Witten [W 1, 2]. 相似文献
43.
Christophe Boss Eric Meurville Jean-Michel Sallese Peter Ryser 《Procedia Chemistry》2009,1(1):313-316
The proof of concept of a continuously sensing affinity device based on the glucose-dependent viscosity of a sensitive solution containing dextran and Concanavalin A has been successfully demonstrated. The biosensor incorporates a piezoelectric diaphragm and a flow-resisting microchannel for viscosity detection, and a free-standing Anodic Alumina Oxide (AAO) porous nano-membrane as glucose selective interface. Extensive in vitro glucose measurements between two physiologically relevant glucose concentrations, 2 mM and 9 mM (respectively hypo- and hyperglycemia), were successfully performed during 4 days. To the best of our knowledge, such reversibility and stability of glucose measurement over time had not been reported yet. 相似文献
44.
The phase space diagram for parabolic and step index fibers leads to a graphic representation of the bound, leaky, and refracted rays of ray theory. This concept is used to predict the attenuation of typical components of local area networks. The technique uses power transfer matrices to track the evolution of power distribution in ray packets. In particular, we predict and then measure the power transfer of two ray packets for a step index fiber. The comparison is encouraging. 相似文献
45.
In situ attenuated total reflection Fourier transform infrared (ATR-FT-IR) spectroscopy has gained considerable attention as a powerful tool for exploring processes occurring at solid/liquid and solid/liquid/gas interfaces as encountered in heterogeneous catalysis and electrochemistry. Understanding of the molecular interactions occurring at the surface of a catalyst is not only of fundamental interest but constitutes the basis for a rational design of heterogeneous catalytic systems. Infrared spectroscopy has the exceptional advantage to provide information about structure and environment of molecules. In the last decade, in situ ATR-FT-IR has been developed rapidly and successfully applied for unraveling processes occurring at solid/liquid interfaces. Additionally, the kinetics of complex reactions can be followed by quantifying the concentration of products and reactants simultaneously in a non-destructive way. In this tutorial review we discuss some key aspects which have to be taken into account for successful application of in situ ATR-FT-IR to examine solid/liquid catalytic interfaces, including different experimental aspects concerned with the internal reflection element, catalyst deposition, cell design, and advanced experimental methods and spectrum analysis. Some of these aspects are illustrated using recent examples from our research. Finally, the potential and some limitations of ATR will be elucidated. 相似文献
46.
Gomila A Le Poul N Cosquer N Kerbaol JM Noël JM Reddy MT Jabin I Reinaud O Conan F Le Mest Y 《Dalton transactions (Cambridge, England : 2003)》2010,39(48):11516-11518
We report the self-induced "electroclick" immobilization of the [Cu(II)(6-ethynyl-TMPA)(H(2)O)](2+) complex, by its simple electro-reduction, onto a mixed azidoundodecane-/decane-thiol modified gold electrode. The redox response of the grafted [Cu(II/I)(TMPA)] at the modified electrode is fully reversible indicating no Cu coordination change and a fast electron transfer. 相似文献
47.
Magali Bonne Stéphane Pronier Fabien Can Xavier Courtois Sabine Valange Jean-Michel Tatibouët Sébastien Royer Patrice Marécot Daniel Duprez 《Solid State Sciences》2010,12(6):1002-1012
Recently titania synthesis was reported using various structuration procedures, leading to the production of solid presenting high surface area but exhibiting moderate thermal stability. The study presents the synthesis of TiO2/SiO2 nanocomposites, a solid that can advantageously replace bulk titania samples as catalyst support. The silica host support used for the synthesis of the nanocomposite is a SBA-15 type silica, having a well-defined 2D hexagonal pore structure and a large pore size. The control of the impregnation media is important to obtain dispersed titania crystals into the porosity, the best results have been obtained using an impregnation in an excess of solvent. After calcination at low temperature (400 °C), nanocomposites having titania nanodomains (~2–3 nm) located inside the pores and no external aggregates visible are obtained. This nanocomposite exhibits high specific surface area (close to that of the silica host support, even with a titania loading of 55 wt.%) and a narrow pore size distribution. Surprisingly, the increase in calcination temperature up to 800 °C does not allow to detect the anatase to rutile transition. Even at 800 °C, the hexagonal mesoporous structure of the silica support is maintained, and the anatase crystal domain size is evaluated at ~10 nm, a size close to that of the silica host support porosity (8.4 nm). Comparison of their physical properties with the results presented in literature for bulk samples evidenced that these TiO2/SiO2 solids are promising in term of thermal stability. 相似文献
48.
The scattering matrix results of Herschel–Quincke (HQ) resonators installed in combination with an acoustic liner (HQ-Liners) are presented in this paper. This approach aims at controlling both tonal and broadband noise to improve the liner efficiency. It uses circumferential arrays of Herschel–Quincke tubes on a main duct in a serial association with a locally reacting liner of known impedance. Results for the scattering matrix of this system are deduced from an analytical model and compared with experimental and numerical data showing a good agreement. Analysis of the scattering matrix coefficients points out the modal conversion properties that depend on the number of HQ tubes along the circumference. Results of the transmission loss show that the choice of an optimal HQ configuration with respect to the liner properties can substantially improve the liner efficiency. 相似文献
49.
50.
Shen NH Massaouti M Gokkavas M Manceau JM Ozbay E Kafesaki M Koschny T Tzortzakis S Soukoulis CM 《Physical review letters》2011,106(3):037403
We experimentally demonstrate, for the first time, an optically implemented blueshift tunable metamaterial in the terahertz (THz) regime. The design implies two potential resonance states, and the photoconductive semiconductor (silicon) settled in the critical region plays the role of intermediary for switching the resonator from mode 1 to mode 2. The observed tuning range of the fabricated device is as high as 26% (from 0.76 THz to 0.96 THz) through optical control to silicon. The realization of broadband blueshift tunable metamaterial offers opportunities for achieving switchable metamaterials with simultaneous redshift and blueshift tunability and cascade tunable devices. Our experimental approach is compatible with semiconductor technologies and can be used for other applications in the THz regime. 相似文献