Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 7

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The paper presents the results of alpha spectrometric measurements of 228Th/232Th and 230Th/232Th activity ratios for many samples of some living species analyzed within last years in our laboratory within different projects. The results were compared with typical values for soil or other non-biological samples. All results were obtained by means of alpha spectrometry.
EN
The paper presents results for the 137Cs, 90Sr, 40K activity concentrations and 228Th/232Th, 230Th/232Th activity ratios in several samples needles from two Norway spruce (Picea abies) trees and two soil samples collected in the Tatra Mountains (Poland) area. Activities for artificial 137Cs and 90Sr show moderate values. Statistically different values were found between the mean concentration of 90Sr and 137Cs in current (C) and two years old (C+2) needles of the first tree, whereas for potassium no significant difference was observed. For the second, fallen tree, no significant difference between the mean activity concentration in needles for C+1 and C+2 was found for each radionuclide, but much lower levels of 137Cs contamination were observed. Observed values of the aggregation coefficients for 137Cs and 90Sr are presented.
EN
The method of obtaining carrier free tracers, 85Sr and 83Rb from proton-irradiated natRbCl target is described. The separation of the radionuclides was done using Sr-Resin, the resin based on a crown ether. Current and some other possible applications of the tracers are discussed.
5
Content available remote Optymalizacja portfela akcji - model Sharpe'a
PL
Artykuł dotyczy zagadnienia optymalizacji składu portfela akcji za pomocą jednej z metod analizy portfelowej - modelu jednowskaźnikowego Sharpe'a. Przedstawiono efekty, jakie dało zastosowanie tego modelu w praktyce na Giełdzie Papierów wartościowych w Warszawie.
EN
The paper is concerned with the optimum number of stock portfolio composition using one of the methods of portfolio analysis, i.e., Sharpe's single-index model. The effects of using the above model in practice at Warsaw Stock Exchange are presented. But to estimate better the expected share rates of return, the trend line was used to count the expected rate of return from market portfolio. The six portfolios created from the different sets of securities and exchange using three different criteria were examined. All the portfolios gained the low results. Each of them brought the negative results while the rate of return from WIG was positive in the same periods time. The reason was the horizontal trend at stock exchange and also the fact of not complying with single-index model assumption about the lack of correlation between the random components of respective stock.
EN
In this work, the response of the Permanent Monitoring Station (PMS) was compared with the readings of environmental thermoluminescent dosimeters (TLD) based on high sensitive MCP-N (LiF:Mg, Cu, P) thermoluminecent detectors and Gamma Tracer, an active device. Thermoluminescent dosimeters were installed close to an automatic warning system of PMS and to a portable Gamma Tracer monitor which is used for long term, continuous measurements in the environment at the INP. For several weeks 137Cs, 60Co, 226Ra and 241Am gamma-ray sources have been placed at distances of a few meters from the dosimeters, in order to modify the radiation environment.
EN
The methods of passive and active shielding and the results of background gamma measurements, during the years 1996-2000 are presented. The spectrometer background was recorded in various shielding configurations. The ultra-low level gamma-spectrometer (called in the paper the spectrometer E), equipped with a veto-detector for cosmic muons (active shield) was under tests during 1999-2000.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.