Observation of antideuteron production in electron-positron annihilation at 10 GeV center of mass energy

The production of antideuterons has been observed in electron-positron annihilations at center-of-mass energies around 10 GeV. Antideuterons have been identified unambiguously by their energy loss in the drift chamber, their time-of-flight and the pattern of their energy deposition in the shower counters of the ARGUS detector. The production rate in the momentum range (0.6?1.8) GeV/c is (1.6_?0.7^+1.0) × 10^?5 per hadronic event.     

In-Line Particle Size Determination for Jet Agglomeration Processes

In jet agglomeration plants, powders are agglomerated to obtain good instant properties. The free-falling initial material is wetted in a spray cone by droplets or in a steam jet by condensation at the particle surface. In a subsequent region of high particle concentration, collision between particles occurs and agglomerates form, if the forces of adhesion are strong enough. A commercial measurement device, working according to the principle of Fraunhofer diffraction, was modified for in-line application. It was used to measure particle size distributions and concentrations of solid particles and droplets in jets. A model is presented to calculate local particle sizes by means of mass balances from integral measurements over large volumes. The results of in-line particle size and agglomerate size analyses show the practical importance of dry agglomeration during transport and lead to a better understanding of the subsequent wet agglomeration process.     

Kühlung eines Grases durch Tröpfchen-Verdampfung

Übersicht Es werden Parallelströmungen von Mischungen aus einem Gas und Tröpfchen desselben Materials behandelt. Stimmen Geschwindigkeit, Temperatur und Dampfdruck der Tröpfchen im Ausgangszustand nicht mit den entsprechenden Gasgrößen überein, so finden Ausgleichsvorgänge zwischen beiden Phasen statt. Hier werden insbesondere solche Fälle untersucht, in denen die Gastemperatur abnimmt. Der Einfluß der verschiedenen Parameter auf diesen Effekt wird für Stickstoff diskutiert.

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Cooling of a gas by evaporation of droplets

Summary Rectilinear flows of mixtures of a gas and droplets consisting of the same material are treated. If the velocity, the temperature and the vapour pressure of the droplets are different from the corresponding values of the gas, equalizing processes occur. Here especially, such cases are considered in which the temperature of the gas decreases. The influence of the various parameters on this effect is discussed for nitrogen.

     

15000 hrs stable operation of resonant cavity light emitting diodes

5 hrs is extrapolated from the degradation rate. The results demonstrate that planar RCLEDs employing one silver (Ag) and one distributed Bragg reflector have high reliability. Received: 3 September 1997/Accepted: 8 September 1997     

Phase-modulation effects in synchronously pumped dye lasers

We report the numerical calculation of pulse generation in SPDL including phase-modulation effects due to gain saturation. The steady-state pulses are strongly down-chirped at the leading edge if the laser frequency is detuned from the line centre of the amplifying dye. The pulse duration is found to be almost independent of wavelength detuning.     

Terpyridine Based Metallo-Supramolecular Initiators: Towards Novel Self-Organizing Materials

[Fe(II){5,5- bis(bromomethyl)-terpyridin}₂](PF₂6)₂2 complexes were used as metallo-supramolecular initiators for the living polymerization of 2-ethyl-2-oxazolines yielding defined hydrophilic polymers with a central supramolecular building unit and star-like architectures. The living character of the polymerization allows an exact control of the molecular weight as well as the incorporation of additional (complexing) units at the polymer chain ends.