Investigations were made in three areas covered by mixed forest. By taking vaginal smears from individually marked females caught in live-traps duration of pregnancy was determined as 22 days. The number of pregnant females varied from 10% to 70% in different months of the reproduction season. The average size of litter, determined by dissection, was 4.9. The percentage of females in the population varied from 36% to 47% on different stations. Calculation was made of how many animals remained in the different areas throughout the whole study period, on the basis of analysis of captures of marked bank voles.

No abstract

No abstract

No abstract

The results of mechanical properties and microstructure observation of low carbon copper bearing steel with high addition of molybdenum are presented in this paper. This steels were characterized by contents of molybdenum in the range from 1,02 to 2.94% wt. After the thermo -mechanical processing the steels were subsequently quenched and tempered in the temperature range from 500• C to 800• C for 1h. The changes of mechanical properties as function of tempering temperature were typical for the steel with the copper addition. The sudden drop of impact resistance after tempering from 575• C to 600• C was caused probably by precipitates of Laves phase of type Fe 2 Mo.Keywords: High Strength Low Alloyed steels (HSLA steels), effect of copper and molybdenum additions, microstructure, mechanical properties, heat treatment W pracy przedstawiono wyniki badań własności mechanicznych oraz obserwacji mikroskopowych nisko węglowych stali z dodatkiem Cu o podwyższonej koncentracji molibdenu w zakresie od 1,02 do 2,94% wag. Po obróbce cieplno-plastycznej stale były hartowane i odpuszczane w zakresie temperatur od 500-800• C przez 1 godzinę. Przebieg zmian własności mechanicznych w funkcji temperatury odpuszczania był zbliżony do przebiegu stali z dodatkiem miedzi. Silny spadek udarności po odpuszczaniu od 575 do 600• C spowodowany był prawdopodobnie procesami wydzieleniowymi fazy Lavesa typu Fe 2 Mo.