X-Ray Powder Diffraction Studies of Polyhydrates of Cross-Linked Tetraisoamylammonium Polyacrylates

X-ray powder diffraction studies were performed of the polyhydrates, formed at positive temperature in swelled grains of carboxylic cation-exchange resins in the form of tetraisoamylammonium (cross-linked tetraisoamylammonium polyacrylates, differing in the degree of cross-linking: 1, 2 and 3%). It was shown that the polyhydrates exist as the crystalline phase under specific conditions, determined earlier by DTA technique. Diffraction patterns of the samples, recorded at the temperature +3 ± 1 °C, indicate that the polyhydrates crystallize in hexagonal symmetry, the unit cell parameters are close to a=12.25 Å, c=12.72 Å and do not depend significantly upon the degree of cross-linking. The suppositions were made concerning the size of hydrate crystallites, formed in the swelled grains of the studied resins.     

High-pressure clathrate hydrate of acetone

X-ray diffraction study of quenched sample of acetone clathrate hydrate synthesized at 0.8 GPa was carried out. It was shown that the host frameworks of the hydrate comprise uniform cavities which are similar to that of recently characterized structure of high-pressure tetrahydrofurane hydrate. The unique peculiarity of investigated hydrate is decrease in the crystallographic symmetry of the hydrate arising from ordering in guest subsystem.     

Study of the plasma potential evolution during ECRH in the T-10 tokamak and TJ-II stellarator

Comparison of the plasma electric potential evolution in the T-10 tokamak and TJ-II stellarator was performed. The core potential was measured by the heavy-ion beam probing and the edge potential was measured by Langmuir probe. The intrinsic potentials in both devices are different in sign, positive in TJ-II low-density discharge and negative in T-10 higher-density discharges, but during ECRH they evolve similarly: the potential becomes more positive, and increase of ECRH power leads to stronger rise of core potential. Presented at the Workshop “Electric Fields, Structures and Relaxation in Edge Plasmas”, Tarragona, Spain, July 3–4, 2005.     

Angular distributions of 240-keV protons transmitted through insulating capillaries

The processes of interaction of accelerated protons with the surface of insulating capillaries have been investigated to determine the character of motion of particles during such interaction. The angular distributions of 240-keV protons transmitted through glass capillaries have been measured, and splitting of the distribution into a series of lines equally spaced from each other is revealed.