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131.
We report studies on the structure of the metallic core and the alkyl cap layer in monolayer protected gold nanoparticles having sizes down to 1.6 nm. These particles are obtained by laser ablating gold targets in alkane-thiol solutions at different concentrations. The electronic structure of gold core and the vibrational properties of the capping hydrocarbon chains reveal effects connected with the nanosized nature of the particles. 相似文献
132.
We apply here the harmonic and Cartan decomposition techniques to piezoelectric material symmetries classification. We show in particular that we shall reduce from 19 to 17 the number of symmetry classes corresponding to the piezoelectric phenomenon. To cite this article: G. Geymonat, T. Weller, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 847–852. 相似文献
133.
Dr. H. Schmieg Prof. Dr. P. Vielsack 《Archive of Applied Mechanics (Ingenieur Archiv)》1987,57(6):446-458
Übersicht Betrachtet wird ein zwangserregtes Zweikörpersystem mit wechselnden Bindungen infolge trockener Reibung. Stationäre Bewegungen werden als Grenzfall instationärer Einschwingvorgänge berechnet. Abhängig von den Systemparametern ergeben sich drei typische Bewegungsformen. Ihnen entsprechen dauernde Haftzustände, wechselnde Haft-Gleitzustände oder dauernde Gleitzustände an der Berührfläche beider Körper.
Intermittant constraints in a two-body-system with dry friction
Summary An externally excited two-body-system with intermittant constraints due to dry friction is considered. Stationary motions are calculated as limit cases of instationary transients. Depending on the parameters of the system, three typical modes are of interest. These correspond to permanent sticking, slipstick behaviour, or to permanent slipping in the contact surface of the bodies, respectively.相似文献
134.
Yun-Zhi Tang Shao-Song Qian Xi-Sen Wang Hong Zhao Xue-Feng Huang Yong-Hua Li Xing-Cai Jiao Ren-Gen Xiong Prof. Dr. 《无机化学与普通化学杂志》2004,630(11):1623-1626
The in situ hydrolysis of phthalyl-γ-glutaminyl-histidine with Cd(ClO4)2·6H2O in the presence of water and methanol affords a novel two-dimensional cadmium coordination polymer, a new phase, anhydrous cadmium(II) phthalate, ( 1 ). The structure was determined by single crystal X-ray diffraction. Crystal data: P21/c, a = 13.8168(14), b = 7.0351(7), c = 8.2054(8) Å, β = 105.540(2)°, V = 768.43(13) Å3, Z = 4, R1 = 0.0380, wR2 = 0.1111. 相似文献
135.
Nicolò Giovannelli Giuseppe Rao Calogero Vetro 《Rendiconti del Circolo Matematico di Palermo》2005,54(3):443-450
In this paper we consider a definition of essentialK-variation for real functions which gives information on the absolute integrability of its approximate derivate on a measurable
set. 相似文献
136.
137.
Vincenzo Santagada Ferdinando FiorinoElisa Perissutti Beatrice SeverinoSara Terracciano Giuseppe CirinoGiuseppe Caliendo 《Tetrahedron letters》2003,44(6):1145-1148
A novel and convenient microwave-assisted dimerization of an active peptide compound using the DKPs as scaffold is described. The key reaction giving rise to the diketopiperazine scaffold is the intermolecular coupling. No epimerization was detected in the reactions used. Conventional and microwave heating of the reactions are compared. Synthesis by microwave irradiation gave the desired compounds in higher yields and in shorter reaction times than those obtained by conventional heating. 相似文献
138.
Giuseppe Coppola Andrea Irace Giovanni Breglio Mario Iodice Luigi Zeni Antonello Cutolo Pasqualina M. Sarro 《Optics and Lasers in Engineering》2003,39(3):317-332
In this paper we describe two different kind of optoelectronic devices both based on a three terminals active device and exploit the plasma dispersion effect to achieve the desired working. The first device exploits this effect in order to obtain an optical modulation. The second device is an optoelectronic router based on the mode-mixing principle together with the injection-induced optical phase shift. Both devices are integrated into a Silicon on Silicon optical channel waveguide which can be realized using a standard bipolar process. The possibility of using standard, well-known technology presents several advantages with respect to III–V Optoelectronics. The active three terminal device used is a Bipolar Mode Field Effect Transistor (BMFET). Numerical simulation results are presented on both devices. 相似文献
139.
Rendiconti del Circolo Matematico di Palermo Series 1 - 相似文献
140.