Radiative lifetimes of excited W II levels

Radiative lifetimes of 19 selected W II levels with energies between 36 000 cm^-1 and 55 000 cm^-1 have been measured with the time-resolved laser-induced fluorescence technique. The ions are generated in a hollow cathode discharge and stored in a linear Paul trap. Selected states are populated with tunable dye laser pulses and the subsequent fluorescence is measured by means of a 5 Gigasample transient digitizer and a fast photodetector with a risetime of 700 ps. By taking into account both the temporal profile of the laser pulses and the separately measured response function of the system, the lifetime can be determined from the full decay curve. A refined evaluation procedure, taking into account saturation effects in the signals, reduces the uncertainty in our data to around 1%. Received: 30 July 1998 / Revised: 18 August 1998     

Permanent-use haemofilter based on porous glass capillaries

Modules of surface-modified porous glass capillaries with a hydraulic conductivity of 0.25-0.70 ml min^-1 mmHg^-1 m^-2 were tested for suitability for clinical haemofiltration by ex vivo dog experiments and by in vitro perfusion. The results show that (1) the construction of reusable haemofilters based on porous glass capillaries is possible; (2) operational data of testmodules are comparable with hollow-fiber high-flux haemofilters based on asymmetric cellulose acetate membranes; and (3) blood-surface interaction of porous glass capillaries is characterized by protein deposition which entails very low protein cutoff.     

Eine Kennzeichnung von Vektorräumen durch ihre affinen Gruppen

Ohne Zusammenfassung     

Influence of Magnetic Susceptibility on Position and Line-width of Proton Magnetic Resonance Lines in Powder Samples of Transition Metal Hydrides

The basic theoretical ideas about the influence of the magnetic susceptibility of the sample material on the nuclear magnetic resonance line position and width of powder samples are discussed. Three different effects may occur the respective influence of which could be derived from multiple-pulse line-narrowing experiments with and without rapid magic-angle sample spinning using powder samples mixed from polymer and metal powders. Measures to avoid the influence of the susceptibility effects are proposed.     

Experimental demonstration of continuous variable purification of squeezed States

We report on the first experimental demonstration of purification of nonclassical continuous variable states. The protocol uses two copies of phase-diffused states overlapped on a beam splitter and provides Gaussified, less mixed states with the degree of squeezing improved. The protocol uses only linear optical devices such as beam splitters and homodyne detection, thereby proving these optical elements can be used for successful purification of this type of state decoherence which occurs in optical transmission channels.