On bifurcations and transition to chaos in a Josephson junction

Chaos in the dc and rf current driven Josephson junction is investigated by measurements on a phase-locked loop. The method allows a direct display of the Poincaré map and the bifurcation diagram, as the parameter space is searched. In some regions of the parameter space the Feigenbaum period-doubling route to chaos is observed upon a change of any parameter.     

Holographic vibration measurement using a tv speckle interferometer with silicon target vidicon

A basic realization of a TV speckle interferometer applying a silicon target vidicon is described. The increased detectivity compared with other vidicons reduces the laser power requirements. This enables stroboscopic operation in a fairly straightforward manner with a He-Ne laser source. Time average- and stroboscopic fringe patterns for a vibrating test object are presented.     

Studies on organophosphorus compounds—IV: HMPA as precursor for dimethylamine in nucleophilic aromatic substitution reactions

The potential leaving groups (NO₂, Cl, Br, OH, OMe) in nucleophilic aromatic substitution reactions are replaced by a dimethylamino group simply by heating the aromatic compounds (activated by cyano- or nitro-groups) in HMPA at elevated temperature.     

Equilibrium configuration and barriers of four fluorine substituted nitrobenzenes,obtained by microwave spectroscopy

MW Spectra of 3- and 4-fluoronitrobenzene in several torsional states and of 2- and 2,4,6-trifluoronitrobenzene in the ground state have been obtained. The inertial defects have been used to show that the 3- and 4-substituted molecules are planar and to find their twofold barriers (1428 cm^?1 and 1213 cm^?1 respectively). The 2- and 2,4,6-substituted molecules have very large negative inertial defects indicating non-planarity. The out-of-plane angles have been calculated (32° and 57° respectively).     

Strongly correlating liquids and their isomorphs

This paper summarizes the properties of strongly correlating liquids, i.e., liquids for which the virial/potential energy correlation coefficient is above 0.9 for equilibrium fluctuations in the NVT ensemble. The definition and properties of strongly correlating liquids' isomorphs are given, and various isomorph invariants are discussed. The cause of strong virial/potential energy correlations is also discussed, and it is argued that strongly correlating liquids are not merely to be thought of as approximate inverse power-law liquids. The experimental predictions for strongly correlating glass-forming liquids include: i) density scaling; ii) isochronal superposition; iii) that there is a single function of frequency from which all frequency-dependent viscoelastic response functions may be calculated; iv) that strongly correlating liquids are approximately single-parameter liquids with close to unity Prigogine-Defay ratio; v) that the fictive temperature initially decreases for an isobaric temperature up jump. The paper also briefly discusses the “isomorph filter”, which provides a necessary condition for universality of theories for the non-Arrhenius temperature dependence of the relaxation time.     

Experimental confirmation of stable, small-debye-length, pure-electron-plasma equilibria in a stellarator

The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20 ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid E x B rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma.     

NMR Studies of (TMTSF)2PF6

Abstract

Pulsed NMR determinations of the relaxation times T₂, T₂* and T₁, as a function of temperature and field, for the methyl group protons in (TMTSF)₂PF₆ are reported. Below the metal-insulator transition (T_MI)T₂* shortens while T₂ increases, indicating a line which is inhomogeneously broadened due to the onset of a SDW. The SDW also contributes to the spin-lattice relaxation rate, T₁ ^?1, in the neighborhood of T_MI. A frequency dependent maximum in T₁ ^?1 is observed near 20K and is attributed to methyl group rotation. A frequency independent maximum at 58K suggests a structural phase transition involving rearrangement of the methyl and PF₆ groups.