Experimental study of negative photoconductivity in n-PbTe(Ga) epitaxial films

We report on low-temperature photoconductivity (PC) in n-PbTe(Ga) epitaxial films prepared by the hot-wall technique on -BaF_2 substrates. Variation of the substrate temperature allowed us to change the resistivity of the films from 10^8 down to 10_{-2} Ohm x cm at 4.2 K. The resistivity reduction is associated with a slight excess of Ga concentration, disturbing the Fermi level pinning within the energy gap of n-PbTe(Ga). PC has been measured under continuous and pulse illumination in the temperature range 4.2-300 K. For films of low resistivity, the photoresponse is composed of negative and positive parts. Recombination processes for both effects are characterized by nonexponential kinetics depending on the illumination pulse duration and intensity. Analysis of the PC transient proves that the negative photoconductivity cannot be explained in terms of nonequilibrium charge carriers spatial separation of due to band modulation. Experimental results are interpreted assuming the mixed valence of Ga in lead telluride and the formation of centers with a negative correlation energy. Specifics of the PC process is determined by the energy levels attributed to donor Ga III, acceptor Ga I, and neutral Ga II states with respect to the crystal surrounding. The energy level corresponding to the metastable state Ga II is supposed to occur above the conduction band bottom, providing fast recombination rates for the negative PC. The superposition of negative and positive PC is considered to be dependent on the ratio of the densities of states corresponding to the donor and acceptor impurity centers.Comment: 7 pages, 4 figure

Repealing Ireland's Eighth Amendment: abortion rights and democracy today

In 2018, the Irish public voted to repeal the Eighth Amendment to the Irish Constitution, which since 1983 banned abortion in the country. While this was a watershed moment in Irish history, it was not unconnected to wider discussions now taking place around the world concerning gender, reproductive rights, the future of religion, Church–State relationships, democracy and social movements. With this Forum, we want to prompt some anthropological interpretations of Ireland's repeal of the Eighth Amendment as a matter concerning not only reproductive rights, but also questions of life and death, faith and shame, women and men, state power and individual liberty, and more. We also ask what this event might mean (if anything) for other societies dealing with similar issues

Analysis of behavior of mine rescuers before and after the rescue on the basis of surveys

W artykule przedstawiono wyniki badań ankietowych dotyczących zachowań, reakcji oraz odczuć ratowników górniczych pod wpływem stresu. Każda akcja ratownicza jest analizowana indywidualnie ze względu na czynniki, które mają wpływ na jej przebieg. Z punktu psychologii ważnym elementem jest zachowanie ratownika, jego reakcje nie tylko przed, jak i w czasie akcji, ale również po przeprowadzonej akcji ratowniczej. Dzięki ankiecie można było zanalizować odczucia ratowników biorących udział w akcjach ratowniczych.The article presents the results of the survey on the behavior, response and feel under stress. Each rescue operation is analyzed individually due to the factors that influence its course. From the point of psychology, an important element is to maintain a lifeguard, his reactions not only before and during the action but also carried out the rescue operation. With the survey you could analyze feelings of rescuers involved in the rescue operations

Selected aspects of occupational adaptation of rescue miners based on the questionnaire research

Publikacja podejmuje problematykę adaptacji zawodowej w górnictwie na przykładzie ratowników górniczych, zatrudnionych w podziemnych zakładach górniczych. Badania przeprowadzono w dwóch losowo wybranych kopalniach węgla kamiennego. Próba badawcza liczyła 52 i 48 ratowników górniczych, co stanowiło po 50% stanu ewidencyjnego załogi kopalnianych stacji ratownictwa górniczego. Do badań sondażowych wykorzystano autorski kwestionariusz ankiety, w którym poddano analizie opinie respondentów w zakresie organizacji adaptacji zawodowej ratowników górniczych oraz odczuć ratowników górniczych podczas adaptacji zawodowej.The publication takes the issues of occupational adaptation in mining for example of rescue miners, employeed in underground coal mines. The study was conducted in two randomly selected hard coal mine, research sample consisted of 52 and 48 rescue miners, which accounted for 50% of the registration status of crew of mine stations of mine rescue. To survey research used original questionnaire, which analysed the respondents’ opinions in the organization of occupational adaptation of rescue miners and the feelings of rescue miners during occupational adaptation

Didactics of specialized subjects for students in the real conditions of the mine underground

W artykule przypomniano powody niedoboru w polskim górnictwie węglowym wykwalifikowanych i obytych z warunkami dołowymi młodych górników. Scharakteryzowano dydaktykę prowadzoną na Wydziale Górnictwa i Geologii Politechniki Śląskiej w zakresie ważnych przedmiotów zawodowych. Omówiono Pole Szkoleniowe znajdujące się w podziemnych wyrobiskach KHW S.A. KWK „ Wujek ", gdzie prowadzone są zajęcia dla uczniów szkół ponadgimnazjalnych zdobywających zawód górnika. Opisano zajęcia laboratoryjne w zakresie aerologii górniczej dla studentów kierunków eksploatacja złóż i zagospodarowanie odpadów (EZiZO) oraz budownictwo podziemne i ochrona powierzchni (BPiOP), które również prowadzone są (na podstawie zawartej umowy) w Polu Szkoleniowym. Podkreślono znaczenie bezpośredniego kontaktu z warunkami dołowymi zarówno studentów, jak i uczniów szkół ponadgimnazjalnych i nowo przyjętych pracowników.The article points out that the Polish mining industry lacks qualified young miners who would be familiar with the conditions of the mine underground. The authors presented the didactics run at the Faculty of Mining and Geology of the Silesian University of Technology in the range of important specialized subjects. The training field placed in the underground of the Wujek mine was described. The field serves as a practical training place for students of secondary mining schools. Additionally, the article de- scribes laboratory classes in the field of mining aerology for students of deposits exploitation and waste management faculties as well as underground construction and surface protection faculties. These classes are run on the training field as well based on an agreement. The authors stresses the significance of direct contact with underground conditions for polytechnic students, secondary school students and newly recruited miners

Correlation between Magnetic and Electronic Properties of Sn1−x\text{}_{1-x}Gdx\text{}_{x}Te

Magnetic susceptibility, electron paramagnetic resonance and transport properties of Sn$\text{}_{1-x}$Gd$\text{}_{x}$Te with 0.04 0.05 no significant change in the magnetic properties was observed after annealing, even at lower hole concentrations. The results can be explained by assuming that an indirect exchange interaction, 4f-5d-band electrons, is responsible for the coupling among Gd ions

Magnetic Properties of EuS/PbS Semiconducting Structures

We report results of magnetization study of EuS/PbS superstructures with different thicknesses of magnetic and nonmagnetic layers. Reduction of ferromagnetic phase transition temperature was found with decreasing EuS thickness. Reasonable description of this effect is obtained within the model based on the mean field approximation