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161.
Minardi Giovannina Mura Emanuela Pistuddi Angelo M. Solinas Costantino Bacchi Alessia Pelizzi Corrado Pelizzi Giancarlo Chelucci Giorgio 《Transition Metal Chemistry》1999,24(4):481-485
Chelating properties of C2-symmetric chiral bipyridine ligands are discussed. In particular we report the syntheses of the cobalt(II), nickel(II), zinc(II) and copper(II) complexes of (4S,5S)-2,2-dimethyl-4,5-bis(2-pyridyl)-1,3-dioxolane. All compounds have been characterized by IR spectroscopy, and an X-ray diffraction analysis has been carried out on one of them: Co(L)(NO3)2. The ligand coordinates the cobalt atom by the two nitrogen donors N(1) and N(2). A seven-membered chelation ring is formed, presenting a remarkable non-crystallographic twofold pseudosymmetry around the axis connecting Co and the midpoint of the C(6)–C(7) bond. The metal also binds two monodentate nitrates, thus completing a distorted coordination tetrahedron. 相似文献
162.
163.
Federico Gallizio Angelo Iollo Bartosz Protas Luca Zannetti 《Physica D: Nonlinear Phenomena》2010,239(3-4):190-201
This investigation concerns solutions of the steady-state Euler equations in two dimensions featuring finite area regions with constant vorticity embedded in a potential flow. Using elementary methods of the functional analysis we derive precise conditions under which such solutions can be uniquely continued with respect to their parameters, valid also in the presence of the Kutta condition concerning a fixed separation point. Our approach is based on the Implicit Function Theorem and perturbation equations derived using shape-differentiation methods. These theoretical results are illustrated with careful numerical computations carried out using the Steklov–Poincaré method which show the existence of a global manifold of solutions connecting the point vortex and the Prandtl–Batchelor solution, each of which satisfies the Kutta condition. 相似文献
164.
Reinaldo A. C. Bianchi Carlos H. C. Ribeiro Anna H. R. Costa 《Journal of Heuristics》2008,14(2):135-168
This paper investigates how to make improved action selection for online policy learning in robotic scenarios using reinforcement
learning (RL) algorithms. Since finding control policies using any RL algorithm can be very time consuming, we propose to
combine RL algorithms with heuristic functions for selecting promising actions during the learning process. With this aim,
we investigate the use of heuristics for increasing the rate of convergence of RL algorithms and contribute with a new learning
algorithm, Heuristically Accelerated Q-learning (HAQL), which incorporates heuristics for action selection to the Q-Learning
algorithm. Experimental results on robot navigation show that the use of even very simple heuristic functions results in significant
performance enhancement of the learning rate. 相似文献
165.
G. Bianchi 《Il Nuovo Cimento C》1990,13(1):177-188
Summary Selenia Spazio was involved since its beginning, more than twenty years ago, in scientific space missions, like almost all
space industries in the world. In fact the European space organizations were mainly devoted to the development of autonomous
launchers and to scientific research in the nearby and in the far away space. First programs in which Selenia Spazio had a
role, designing and manufacturing space electronic equipment, were scientific satellites and ELDO launchers, followed by COSB
and other cosmic research missions. In all these years cosmic physics and related research programs continued to receive technological
support and see full involvement by space industry.
To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee. 相似文献
166.
167.
168.
A. Ignatov V. Bellini J.P. Bocquet M. Capogni M. Casano A. D’Angelo J.-P. Didelez A. Fantini G. Gervino B. Girolami A. Giusa M. Guidal V. Kouznetsov A. Lapik A. Lleres A. Mushkarenkov L. Nicoletti D. Rebreyend N. Rudnev G. Russo M.-L. Sperduto M.-C. Sutera 《Progress in Particle and Nuclear Physics》2008,61(1):253-259
New experimental approach to study meson photoproduction in nuclei is discussed. It is based on the measurement of the recoil nucleon as a tagger for identification of the initial step of reaction. Propagation of mesons and nucleons within a nucleus is described by the Intra-Nuclear Cascade (INC) model. Simulations and preliminary experimental data for the deuteron target obtained at GRAAL are presented. 相似文献
169.
Angelo C. Pinto Barbara Vasconcellos da Silva Jaïrton Dupont 《Tetrahedron letters》2008,49(39):5639-5641
An efficient method was developed for the preparation of isatin-3-oxime derivatives with Bronsted and/or Lewis acids in imidazolium-based ionic liquids. Isatin-3-oxime bearing the electron donating methoxy group was equally obtained in good yields. The pronounced ionic liquid effect avoids the direct formation of isatin in the acidified media and the reaction leads exclusively to isatin-3-oxime derivatives. 相似文献
170.
Summary
In un precedente articolo [2]G. Mägerl ed il secondo autore hanno dimostrato la buona posizione del problema ricostruttivo di Hammer, imponendo che il corpo convesso da ricostruire fosse contenuto in un preassegnato insieme limitato. Si dimostra qui che tale limitazione può essere tolta.Ricerca finanziata con fondi MPI. 相似文献