Tandem nitrosation/cycloaddition of heterocyclic enamines using nitrolic acids

The reaction of alkylidenepyrrolidines with nitrolic acids gives rise to the formation of novel 3,7a-disubstituted (1,2,4-oxadiazol-5-yl)-5,6,7,7a-tetrahydropyrrolo[1,2-d][1,2,4]oxadiazoles. A plausible mechanism for this reaction is proposed, which features nitrosation of the enamine by the nitrous acid that is liberated from the nitrolic acid.     

Von den vielen Verfahren zum Nachweis von kleinsten Mengen Formaldehyd

Ohne Zusammenfassung     

Hilbert空间中非扩张映象的最近的公共不动点的逼近问题

本文在Hilbert空间的框架下,研究无限族非扩张映象T_1,T_2,…的迭代程序x_n+1=λ_(n+1)y+(1-λ_(n+1))T_(n+1)x_n的收敛性问题．在适当的条件下,证明了该迭代序列收敛于这一非扩张映象族的最近的公共不动点．其结果改进和推广了引文中相应的结果．     

All-optical logic AND-NOR gate with three inputs based on cross-gain modulation in a semiconductor optical amplifier

We report the realization of a novel all-optical logic AND-NOR gate based on cross-gain modulation (XGM). The used scheme requires only one SOA to perform the logic gate with three input signals. A 8.5 dB dynamic extinction ratio with a switching time of about 650 ps for the rise time and 100 ps for the fall time.     

Large-Amplitude Periodic Oscillations in Simple and Complex Mechanical Systems: Outgrowths from Nonlinear Analysis

In this paper, we survey developments in nonlinear partial differential equations and applications since the original paper of Ambrosetti and Prodi on nonlinearities that cross eigenvalues. We show how this work has important developments in nonlinear analysis, and survey the implications for periodically forced mechanical systems, from simple one-particle vibrating systems to suspension bridges and ships. Lecture held in the Seminario Matematico e Fisico on March 9, 2005 Received: December 2005     

Parabolic Actions in type A and their Eigenslices

The main theme of this paper is that many of the remarkable properties of invariant theory pertaining to semisimple Lie algebras carry over to parabolic subalgebras even though the latter have less structure. This includes the polynomiality of the invariant subalgebra of the symmetric algebra of a (truncated) parabolic subalgebra, the existence of a slice to the regular coadjoint orbits and the construction of maximal Poisson commutative polynomial subalgebras by "shift of argument". The first of these properties was established for most parabolics in [FJ1]. Here the existence of a slice to (most) regular coadjoint orbits is established for parabolics in type A which are invariant under the Dynkin diagram involution. In a subsequent paper [JL] maximal Poisson commutative polynomial subalgebras are described for those (truncated) parabolics in sl(n) having index n - 1.     

Comparison of a subrank to a full-rank time-reversal operator in a dynamic ocean

This paper investigates the application of time-reversal techniques to the detection and ensonification of a target of interest. The focusing method is based on a generalization of time-reversal operator techniques. A subrank time-reversal operator is derived and implemented using a discrete set of transmission beams to ensonify a region of interest. In a dynamic ocean simulation, target focusing using a subrank matrix is shown to be superior to using a full-rank matrix, specifically when the subrank matrix is captured in a period shorter than the coherence time of the modeled environment. Backscatter from the point target was propagated to a vertical 64-element source-receiver array and processed to form the sub-rank time-reversal operator matrix. The eigenvector corresponding to the strongest eigenvalue of the time-reversal operator was shown to focus energy on the target in simulation. Modeled results will be augmented by a limited at-sea experiment conducted on the New Jersey shelf in April-May 2004 measured low-frequency backscattered signal from an artificial target (echo repeater).     

Coexistence of self-organized criticality and intermittent turbulence in the solar corona

An extended data set of extreme ultraviolet images of the solar corona provided by the SOHO spacecraft is analyzed using statistical methods common to studies of self-organized criticality (SOC) and intermittent turbulence (IT). The data exhibit simultaneous hallmarks of both regimes: namely, power-law avalanche statistics as well as multiscaling of structure functions for spatial activity. This implies that both SOC and IT may be manifestations of a single complex dynamical process entangling avalanches of magnetic energy dissipation with turbulent particle flows.