Electronic Structure and X-Ray Photoelectron Spectra of Some Perovskite Molecular Crystals

It is new study of some molecular crystals with a perovskite structure, whose luminescent, thermochromic, nonlinear optical and dielectric properties provide opportunities for their wide practical application. This paper presents the results of an investigation of the electronic structure and the orbital nature of crystals with the AMX6 formula (where A = Cs, HGu; M = Te, Sb, Ir, Os, Re, W; X = F, Cl, Br). The electronic structure of crystals with Te and Sb atoms was determined by the method of X-ray photoelectron spectroscopy and quantum-chemical modeling within the framework of the density functional theory. We identified the molecular orbitals which are responsible for covalent metal-halogen binding. Also we found that the transition from the 3a1g highest occupied molecular orbital to the 4t1u lowest unoccupied molecular orbital, which corresponds to the states 1T1u and 3T1u, is responsible for the luminescence of the [MX6] 2– anions

Study of Characteristics of the Quasi-spherical Measurement Modules of the Cherenkov Water Calorimeter NEVOD

AbstractThe use of quasi-spherical modules with several PMTs with flat photocathodes in Cherenkov water detectors is discussed. Properties of the response of such modules are examined. The characteristics of the quasi-spherical module with six PMTs that is used in the Cherenkov water calorimeter NEVOD are considered. The results of studying the isotropy of the amplitude response of this module and the quality of reconstruction of light direction with a single module and with a group of modules are demonstrated

Registration of atmospheric neutrinos with the Baikal neutrino telescope

We present first neutrino induced events observed with a deep underwater neutrino telescope. Data from 70 days effective life time of the BAIKAL prototype telescope NT-96 have been analyzed with two different methods. With the standard track reconstruction method, 9 clear upward muon candidates have been identified, in good agreement with 8.7 events expected from Monte Carlo calculations for atmospheric neutrinos. The second analysis is tailored to muons coming from close to the opposite zenith. It yields 4 events, compared to 3.5 from Monte Carlo expectations. From this we derive a 90 % upper flux limit of 1.1 * 10^-13 cm^-2 sec^-1 for muons in excess of those expected from atmospheric neutrinos with zenith angle > 150 degrees and energy > 10GeV.Comment: 20 pages, 11 figure

The Lake Baikal neutrino experiment

We rewiew the present status of the Baikal Neutrino Project and present the results of a search for high energy neutrinos with the detector intermediate stage NT-96.Comment: 3 pages, 2 figures, to appear in the Proceedings of Sixth International Workshop on Topics in Astroparticle and Underground Physics (TAUP99), September 6-10, 1999, Pais, Franc

Status of the Lake Baikal Experiment

We review the present status of the Baikal Underwater Neutrino Experiment and report on neutrino events recorded with the detector stages NT-36 and NT-96.Comment: 5 pages, 4 PostScript figures, uses here.sty and mine.sty, submitted to the Proc. of 5th Int. Workshop on Topics in Astroparticle and Underground Physics (LNGS INFN, Assergi, September 7-11, 1997

The Baikal Deep Underwater Neutrino Experiment: Results, Status, Future

We review the present status of the Baikal Underwater Neutrino Experiment and present results obtained with the various stages of the stepwise increasing detector: NT-36 (1993-95), NT-72 (1995-96) and NT-96 (1996-97). Results cover atmospheric muons, first clear neutrino events, search for neutrinos from WIMP annihilation in the center of the Earth, search for magnetic monopoles, and -- far from astroparticle physics -- limnology.Comment: Talk given at the Int. School on Nuclear Physics, Erice, Sept.199

THEORY AND PRACTICE IN THE DEVELOPMENT OF TWO-DISC DISTRIBUTING DEVICES FOR SEED PREPARATION

One way of preserving grain from harvest to emergence is to prepare the seed for sowing. It is known as seed dressing. Single-disc chamber seed dressers are the most widely used, but at maximum flow rates the quality of the treatment is significantly reduced. Therefore, the purpose of the study was to develop a treatment chamber distributor to improve the quality of seed dressing in cereal crops. To solve this problem, it was necessary to develop a double-disc distributing device which is capable to improve the quality of treatment, to carry out a theoretical justification of its application, as well as to give a preliminary evaluation of the device use under laboratory conditions. For this reason, a double-disc distributing device has been developed. It is capable of redistributing the seed flow between the lower solid disc and the upper annular disc when changing the flow rate. Classical mechanics and mathematics were the basis of theoretical research. As a result, we have determined the forces exerting on the seed, the differential equations of motion of a constrained material particle and the motion of the seed on rotating discs in analytical form of a two-disc distributing device consisting of upper annular and lower solid discs with polymer spreaders, and the critical speed of the drive shaft 13,5 s-1, which determines the moment of the seed sliding on discs. The actual angular velocity (56.5 s-1) was found to be 4.2 times greater than the critical velocity of 13.5 s-1, which is sufficient to produce a uniform flow of seeds with discs directed towards the deflectors. The evaluation of the application of the developed device under laboratory conditions provides a maximum seed supply of 5.84 kg/s, a non-uniformity of 3.1 %, and a seed crushing of 0.04% by the dresser. This has a positive effect on the seed dressing quality

Energy spectrum of cascade showers initiated by cosmic ray muons in the Cherenkov water detector

Results of analysis of experimental data on cascade showers with energies of 0.1 – 10 TeV initiated by muons in the Cherenkov water detector NEVOD are presented. The method of selection and reconstruction of cascade parameters in the volume of the detector is discussed. Experimental distributions of cascade axes in zenith angle and energy spectrum of cascades are obtained. The measured distributions are compared with results of calculations

Energy spectrum of cascade showers initiated by cosmic ray muons in the Cherenkov water detector

Results of analysis of experimental data on cascade showers with energies of 0.1 – 10 TeV initiated by muons in the Cherenkov water detector NEVOD are presented. The method of selection and reconstruction of cascade parameters in the volume of the detector is discussed. Experimental distributions of cascade axes in zenith angle and energy spectrum of cascades are obtained. The measured distributions are compared with results of calculations