18,906 research outputs found
Interactions of large amplitude solitary waves in viscous fluid conduits
The free interface separating an exterior, viscous fluid from an intrusive
conduit of buoyant, less viscous fluid is known to support strongly nonlinear
solitary waves due to a balance between viscosity-induced dispersion and
buoyancy-induced nonlinearity. The overtaking, pairwise interaction of weakly
nonlinear solitary waves has been classified theoretically for the Korteweg-de
Vries equation and experimentally in the context of shallow water waves, but a
theoretical and experimental classification of strongly nonlinear solitary wave
interactions is lacking. The interactions of large amplitude solitary waves in
viscous fluid conduits, a model physical system for the study of
one-dimensional, truly dissipationless, dispersive nonlinear waves, are
classified. Using a combined numerical and experimental approach, three classes
of nonlinear interaction behavior are identified: purely bimodal, purely
unimodal, and a mixed type. The magnitude of the dispersive radiation due to
solitary wave interactions is quantified numerically and observed to be beyond
the sensitivity of our experiments, suggesting that conduit solitary waves
behave as "physical solitons." Experimental data are shown to be in excellent
agreement with numerical simulations of the reduced model. Experimental movies
are available with the online version of the paper.Comment: 13 pages, 4 figure
Generation of Hyperentangled Photons Pairs
We experimentally demonstrate the first quantum system entangled in every
degree of freedom (hyperentangled). Using pairs of photons produced in
spontaneous parametric downconversion, we verify entanglement by observing a
Bell-type inequality violation in each degree of freedom: polarization, spatial
mode and time-energy. We also produce and characterize maximally hyperentangled
states and novel states simultaneously exhibiting both quantum and classical
correlations. Finally, we report the tomography of a 2x2x3x3 system
(36-dimensional Hilbert space), which we believe is the first reported photonic
entangled system of this size to be so characterized.Comment: 5 pages, 3 figures, 1 table, published versio
A six-coordinate aryl-germanium complex formed by the Kläui ligand
PhGeClâ reacts with Na{[OP(OEt)â]âCoCp} to give the six-coordinate complex PhClâGe{[OP(OEt)â]âCoCp}, characterised spectroscopically and by an X-ray crystal structure determination which showed a firmly-attached tridentate ligand [GeâO 1.973(2) Ă
]
Novel six-coordinate Aryl- and Alkyltin complexes
Organo-tin compounds have wide applications as pesticides and as intermediates for organic synthesis.š They are invariably Sn(IV) derivatives and are generally four-coordinate.² The mixed organo/chioro compounds of the type RnSnCI4-n do however have the ability to expand their coordination numbers to five or six. This depends critically on the substituents - with four organic groups, RâSn, there is no tendency at all to coordinate extra ligands, while at the other extreme SnClâ readily forms six-coordinate [SnC1âLâ] complexes since the electronegative halo groups increase the Lewis acidity of the tin centre
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