Synthesis and X-ray structure analysis of host-guest complexes (H4L)(SiF6)2-4H2O (I) and (H4L)(GeF6)2-4H2O (II) are reported (L = meso-5,7,7,12,12,14-hexamethyl-l,4,8,11-tetraazacyclo-tetradecane). ...The crystals of both compounds are triclinic with close unit cell parameters. I: a = 9.576(3), b= 9.217(3), c= 8.334(2) å, α= 105.66(2), Ω= 83.68(2), α = 105.38(2)‡ II: a= 9.627(3), b = 9.358(3), c.= 8.497(4) A, a= 106.02(2), Ω = 83.74(2), α= 106.06(2)‡. The structural units of the crystals are the (H4L)4+ cations, the hexafluorosilicate (or hexafluowgemanate) anions, and the water molecules linked by a system of H bonds. The macrocycle in the complexes has C1 symmetry. In the inorganic anions, the silicon as well as germanium atom is surrounded by an octahedron of six fluorine atoms.
The interaction between BF3 (C2H5)2Oand a racemate of 5,7,7,12,12,14-hexamethyl-l,4,8,11-tetraazacyclotetradecane (L) in the presence of air moisture leads to the complex (LH2) BF4)2- H2O (I), whose ...structure was determined by X-ray structure analysis and confirmed by thermogravimetric data. The crystals are monoclinic, C16H40B2F8N4O, space group P21ln, a-25.570(7), b = 11.231(5), c = 8.715(4) å, α = 97.32(3)‡, Z = 4, the final R value is 0.0753 for 2800 unique reflections. The structure is built from the double-charged organic cations of the tetraazamacrocycle, tetrafluoroborate anions, and water molecules (1:2:1) linked by a system of hydrogen bonds of NH...F, NH...O, and OH...F type, in which all the four macrocycle nitrogens perform the function of proton donors. The macrocycle in the complex has approximately C2 symmetry.
The 5N neutral particle beamline at the U-70 accelerator (Institute for High Energy Physics), which has been designed to produce a high-intensity neutron beam with the highest possible energy, is ...described. The average neutron energy is ∼51 GeV, and the beam intensity is up to 10
7
neutrons per spill. For several years, this beam has been used to investigate charmed particles and narrow baryon resonances in neutron-nucleus interactions and search for exotic multiquark states with the aid of the EXCHARM spectrometer.
The level of emotional stress depending on the power of motivation and the estimation by the subject of the probability (possibility) of goal achievement, largely influences the operator's skill ...performance (that of a pilot, controller, astronaut). A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals, and to slower reactions. The extremely high stress level disorganizes the activity, complicates it with a trend toward untimely acts and reactions to the insignificant signals (false alarms). The best methods to monitor the degree of the operator's emotional state during his skill performance are the integral estimation of the changes in heart-rate and T-peak amplitude, as well as the analysis of spectral and intonational characteristics of the human voice during radio conversation. These methods were tested on paratroopers, pilots in civil aviation, and airport controllers.
