Metal-insulator transition revisited for cold atoms in non-Abelian gauge potentials

We discuss the possibility of realizing metal-insulator transitions with ultracold atoms in two-dimensional optical lattices in the presence of artificial gauge potentials. For Abelian gauges, such transitions occur when the magnetic flux penetrating the lattice plaquette is an irrational multiple of the magnetic flux quantum. Here we present the first study of these transitions for non-Abelian U(2) gauge fields. In contrast to the Abelian case, the spectrum and localization transition in the non-Abelian case is strongly influenced by atomic momenta. In addition to determining the localization boundary, the momentum fragments the spectrum. Other key characteristics of the non-Abelian case include the absence of localization for certain states and satellite fringes around the Bragg peaks in the momentum distribution and an interesting possibility that the transition can be tuned by the atomic momenta.     

Titrimetrische Bestimmung der Doppelphosphate von Ammonium mit Cadmium, Kobalt, Mangan und Zink

Ohne ZusammenfassungAus dem Englischen übersetzt von der Redaction.     

Optical fiber sensors using hollow glass spheres and CCD spectrometer interrogator

Hollow glass micro-spheres, firstly used to make fiber optic sensors for high hydrostatic pressure, have been interrogated using a high-resolution CCD-based spectrometer, to give far better precision than conventional spectrometric read out. It is found that these simple, low-cost micro-sensors have excellent sensitivity to both static and dynamic pressure, and have the advantage of being hermetically sealed. Many other application areas are foreseen for these low-cost sensors.     

Die Bestimmung des Zinks als Phosphat

Ohne Zusammenfassung     

Als Methode zur Trennung der Aminos?uren

Ohne Zusammenfassung     

4 + 2]-annulations of chiral organosilanes: Application to the total synthesis of leucascandrolide A

Complete details of an asymmetric synthesis of leucascandrolide A (1) are described. The synthesis highlights the use of two diastereoselective [4 + 2]-annulations for the assembly of the functionalized bispyranyl macrolide 3. An efficient assembly and union of the oxazole-containing side chain 4 with macrolide 3 was carried out using a Mitsunobu reaction. A convergent route to the oxazole side chain was developed using a Sonogashira cross-coupling between 2-trifloyloxazole 16 and alkyne 17, which allowed for the installation of the C9'-C10' (Z)-olefin.     

Zur Bestimmung von Mangan und Kobalt als Phosphat

Ohne Zusammenfassung     

Relaxation processes in glasses as shown by optical attenuation experiments

Some optical attenuation experiments on both bulk glasses and cladded glass fibres (fibre optics) are described. They reveal the presence of relaxation processes in the glass in its transformation range.     

Nonequilibrium lighting plasmas

The science of a variety of devices employing nonequilibrium lightning plasmas is reviewed. The devices include the fluorescent lamp, the low-pressure sodium lamp, the neon sign, ultraviolet lamps, glow indicators, and a variety of devices used by spectroscopists, such as the hollow cathode light source. The plasma conditions in representative commercial devices are described. Recent research on the electron gas, the role of heavy particles, spatial and temporal inhomogeneities, and new electrodeless excitation schemes is reviewed. Areas of future activity are expected to be in new applications of high-frequency electronics to commercial devices, new laser-based cidiagnostics of plasma conditions, and more sophisticated models requiring more reliable and extensive rate coefficient data