RESUMO
In this Letter, a new approach to distinguish liquid water and ice based on dual spectrum neutron radiography is presented. The distinction is based on arising differences between the cross section of water and ice in the cold energy range. As a significant portion of the energy spectrum of the ICON beam line at Paul Scherrer Institut is in the thermal energy range, no differences can be observed with the entire beam. Introducing a polycrystalline neutron filter (beryllium) inside the beam, neutrons above its cutoff energy are filtered out and the cold energy region is emphasized. Finally, a contrast of about 1.6% is obtained with our imaging setup between liquid water and ice. Based on this measurement concept, the temporal evolution of the aggregate state of water can be investigated without any prior knowledge of its thickness. Using this technique, we could unambiguously prove the production of supercooled water inside fuel cells with a direct measurement method.
Assuntos
Congelamento , Gelo , Difração de Nêutrons/métodos , Água/química , Berílio/química , Difração de Nêutrons/instrumentaçãoRESUMO
The aim of the project is a comprehensive analysis of psychotherapeutic outcome research from a differential perspective. All controlled psychotherapy outcome studies which have been published until 1983 (n = 897) were carefully analyzed with an especially developed assessment-manual. Special importance was laid on those features of the results that throw some light on the comparative effects and prescriptive criteria of the therapies under investigation and their preconditions in the experimental design, measurement and statistical analysis of the respective study. The procedure is described in detail. It results in a comprehensive report on the research which has been done and the results that have been found for each psychotherapy method. An example of such a report is given.