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171.
Claudio Rea 《Annali di Matematica Pura ed Applicata》1976,110(1):161-175
Sunto Si dimostra l'esistenza della soluzione per l'operatore di Cauchy-Riemann parametrizzato, nel caso continuo per varietà fortemente
pseudoconvesse e nel caso differenziabile per varietà di Stein.
Entrata in Redazione il 20 maggio 1975.
Supported by C.N.R. research groups. 相似文献
Entrata in Redazione il 20 maggio 1975.
Supported by C.N.R. research groups. 相似文献
172.
Claudio Teitelboim 《Physics letters. [Part B]》1977,69(2):240-244
It is shown that in asymptotically flat space the weakly vanishing Hamiltonian of supergravity theory has to be modified by adding to it certain surface integrals. The numerical value of the surface integrals yields the total energy-momentum, angular momentum and supercharge of the system. The surface integrals have well defined (Dirac) brackets only after the coordinates and supergauge are fixed. In that case they close according to the flat space supersymmetry algebra. If an internal symmetry is included, new surface integrals appear corresponding to the additional gauge charges. 相似文献
173.
Canevali C Mari CM Mattoni M Morazzoni F Nodari L Ruffo R Russo U Scotti R 《The journal of physical chemistry. B》2005,109(15):7195-7202
The mechanism of NO interaction with nanosized Ru(Pd,Pt)-doped SnO(2) was studied by electron paramagnetic resonance, M?ssbauer, and electric resistance measurements. Three steps were proposed for the reaction between the semiconductor oxide and the gaseous component: (i) the formation of bielectronic oxygen vacancies (V(o)) in SnO(2); (ii) their single-ionization (V(o)(*)) with injection of electrons into the SnO(2) conduction band; (iii) the subsequent transfer of electrons from V(o)(*) to [Ru(Pd,Pt)](4+). The last process induces the formation of further oxygen vacancies which reduce the transition metal centers to lower oxidation states; the redox processes is enhanced and the electrical resistance in transition metal-doped SnO(2) is stronger modified with respect to the undoped material. 相似文献
174.
Edoardo Ballico Claudio Fontanari Cristiano Bocci Enrico Carlini 《Rendiconti del Circolo Matematico di Palermo》2004,53(3):429-436
We generalize the classical Terracini’s Lemma to higher order osculating spaces to secant varieties. As an application, we
address with the so-called Horace method the case of thed-Veronese embedding of the projective 3-space.
This research is part of the T.A.S.C.A. project of I.N.d.A.M., supported by P.A.T. (Trento) and M.I.U.R. (Italy). 相似文献
175.
Near a Mott transition, strong electron correlations may enhance Cooper pairing. This is demonstrated in the dynamical mean field theory solution of a twofold-orbital degenerate Hubbard model with an inverted on-site Hund rule exchange, favoring local spin-singlet configurations. Close to the Mott insulator (which here is a local version of a valence bond insulator) a pseudogap non-Fermi-liquid metal, a superconductor, and a normal metal appear, in striking similarity with the physics of cuprates. The strongly correlated s-wave superconducting state has a larger Drude weight than the corresponding normal state. The role of the impurity Kondo problem is underscored. 相似文献
176.
177.
178.
Uranium analysis in fish, echinoderms and shellfish samples collected in the north part of the Adriatic Sea is presented. The aim of the work was to evaluate uranium concentrations in samples of this kind, and also to investigate possible contamination from depleted uranium (DU) in consequence of the war operations previously conducted in that area. DU contamination was checked by measuring the (235)U/(238)U isotope ratio. The samples were dissolved according to the EPA 3052 procedure, and the determinations were performed by inductively coupled plasma mass spectrometry (ICP-MS), optimized in order to perform isotope ratio measurements with good precision. The method was validated by evaluating the recovery from spiked samples; results in the range 93-107% were obtained. The isotope ratio measurement was evaluated in terms of accuracy and precision by analyzing the certified reference materials IAEA 326 and GBW 07305, and good agreement with the certified values was obtained here also. The concentration of uranium was higher in invertebrate samples than in fish (0.3-2 microg/g of U vs. 0.05-0.1 microg/g, respectively). The isotope ratio measurements for all the samples gave values very similar to the natural ratio, permitting exclusion of the presence of DU. 相似文献
179.
Cholesterol oxidation in commercial meat-based homogenized and freeze-dried baby foods was examined. The 7 major products of this reaction were determined by gas chromatography coupled with mass spectrometry (GC-MS). As far as single cholesterol oxidation products (COP) are concerned, 7-ketocholesterol was the major product of direct cholesterol oxidation in the 2 groups of analyzed samples, and this study confirmed that it is a useful marker of the whole cholesterol oxidation process. Nevertheless, the amounts of cholesterol-5beta,6beta-epoxide were often similar to and sometimes higher than the amounts of 7-ketocholesterol, thus showing a strong development of both direct and indirect cholesterol oxidation pathways. Total COP content was significantly higher in freeze-dried than in homogenized products. Moreover, in freeze-dried samples, the COP content per serving was quite variable and, in 2 samples, it was close to or even higher than 500 microg. The greater development of cholesterol oxidation in the freeze-dried samples was confirmed by their highest total COP/cholesterol percent ratios. A constant correlation between the fatty acid composition and the development of cholesterol oxidation was not found, although a positive correlation between unsaturated fatty acid content and total COP content occasionally exists in samples of the same brand. 相似文献
180.
Barbaro P Bianchini C Giambastiani G Oberhauser W Bonzi LM Rossi F Dal Santo V 《Dalton transactions (Cambridge, England : 2003)》2004,(12):1783-1784
New systems based on cationic chiral phosphine-rhodium complexes anchored to a commercial cation-exchange gel-type resin showed high efficiency and easy recycling in the asymmetric hydrogenation of prochiral olefins. 相似文献