Another TAS instrument and a 4-circle materials test diffractometer are being installed on thermal neutron beams. A new reflectometer was recently installed on a neutron guide, we are sharing the construction and utilisation of this instrument. For example in 1997 nearly 50 experiments were completed by the local staff and in collaboration with national or foreign users coming from university, industrial or other research laboratories. Our research programme and recent results cover, basically, three fields of materials and in the followings a few examples of this research activity are listed. Phase transitions in aqueous solutions.
Water is the most important solvent in our life.
The measurements prove the presence of definite inhomogeneities with size of 20 - 30 nm. By elevating the temperature to about -90 oC these aggregates disappear and at further increase of temperature the SANS pattern recovers again. Approaching to room temperature this effect suddenly disappears. It was established that the nature of these inhomogeneities is connected with the presence of iron-perchlorate reach regions. Moreover, we succeeded in discovering a collective effect in this system, manifested in new phase transitions from a disordered quenched to crystalline state with an intermediate re-entrant amorphous phase.