Search results for "Source material"
showing 4 items of 4 documents
ACTINIDE AND ULTRA-HEAVY ABUNDANCES IN THE LOCAL GALACTIC COSMIC RAYS: AN ANALYSIS OF THE RESULTS FROM THELDEFULTRA-HEAVY COSMIC-RAY EXPERIMENT
2012
The LDEF Ultra-Heavy Cosmic-Ray Experiment (UHCRE) detected Galactic cosmic rays (GCRs) of charge Z ≥ 70 in Earth orbit with an exposure factor of 170 m2 sr yr, much larger than any other experiment. The major results include the first statistically significant uniform sample of GCR actinides with 35 events passing quality cuts, evidence for the existence of transuranic nuclei in the GCR with one 96Cm candidate event, and a low 82Pb/78Pt ratio consistent with other experiments. The probability of the existence of a transuranic component is estimated as 96%, while the most likely 92U/90Th ratio is found to be 0.4 within a wide 70% confidence interval ranging from 0 to 0.96. Overall, the resu…
Lukion historian opettajien käsityksiä esseen arviointiin vaikuttavista piirteistä
2021
Artikkelissa tarkastellaan lukion historian opettajien käsityksiä aineistopohjaisen esseen arvioinnista ja siihen vaikuttavista piirteistä tiedonalan tekstitaitojen näkökulmasta. Aineisto koostuu opettajien ryhmähaastatteluista ja lukiolaisten kirjoittamista aineistopohjaisista esseistä. Haastattelut analysoitiin laadullisen sisällönanalyysin avulla ja esseiden kielellisiä piirteitä systeemis-funktionaalisen kieliteorian avulla. Analyysissä keskityttiin opettajien arvostamiin esseen piirteisiin ja niiden kielellisiin toteumiin. Opettajien arvostamissa piirteissä korostuivat erityisesti sisältötiedon hallinta sekä tehtävänannon noudattaminen. Aineiston käyttöön ja opiskelijan omaan pohdintaa…
Growth of ZnO crystals by vapour transport: Some ways to act on physical properties
2006
Nowadays, the growth of ZnO by vapor transport in silica ampoules is generally made in presence of graphite. As it has been already shown, this means that the growth process is carried out in presence of a Zn excess. In order to control that and act, as a consequence, on the physical properties of crystals we have performed a systematic study of the growth process in a wide range of Zn excess compositions using well defined experimental conditions. As a preliminary characterization, optical absorption and electrical properties have been analyzed at room temperature. The results show how some physical properties of as-grown ZnO crystals can be changed in a controlled way by an adequate combi…
Argument graph as a tool for promoting collaborative online reading
2012
This study explored how the construction of an argument graph promotes students' collaborative online reading compared to note-taking. Upper secondary school students (n = 76) worked in pairs. The pairs were asked to search for and read source material on the Web for a joint essay and either construct an argument graph or take notes during online reading. The data consist of transcription protocols of student pairs' discussions and joint essays. The study indicated that argument graphs may be useful tools when teachers want students to pay attention to the argumentative content of online sources and to consider relations between arguments. Additionally, with argument graphs, teachers can su…