Distributions of mass of cluster ion beams were investigated by using a Wien filter with permanent magnets, which is 200 mm in length. Resolving powers of the Wien filter in the mass range of 103 to 106 a.m.u. were estimated. The Wien filter is useful for studies of clusters having 102–104 molecules/cluster. Argon cluster beams were ionized up to about ten charges when ionizing current was 15 mA. There were two different mass groups in hydrogen cluster beams produced, even at gas temperature of 77.3 K.

We apply canonical Poisson-Lie T-duality transformations to bosonic open string worldsheet boundary conditions, showing that the form of these conditions is invariant at the classical level, and therefore they are compatible with Poisson-Lie T-duality. In particular the conditions for conformal invariance are automatically preserved, rendering also the dual model conformal. The boundary conditions are defined in terms of a gluing matrix which encodes the properties of D-branes, and we derive the duality map for this matrix. We demonstrate explicitly the implications of this map for D-branes in two non-Abelian Drinfel'd doubles.

Classical condensation theory is used to predict cluster production in a nozzle with a slit-throat. The basic idea underlying this nozzle is that a slit-throat nozzle is approximately equivalent to a linear array of axisymmetric nozzles of diameter equal to the throat width. The results of computation show that the slit-throat nozzle can produce a cluster beam of high total flux with a constant cluster size, and are approximately in agreement with those of experiments.