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Povzetek: The selection of the most suitable material for the EU DEMO divertor is still underway. Current research focuses on the development of tungsten-based materials for plasma-facing applications. In addition to other requirements, the candidate material must also exhibit low intrinsic hydrogen isotope retention. To verify the suitability of the tungsten carbide-containing materials, we examined the effect of carbon in the form of carbide or free carbon on deuterium (D) retention. The samples were consolidated by Field Assisted Sintering (FAST) and examined in terms of phase composition and microstructure before the d-retention studies. The Nuclear Reaction Analysis (NRA) technique was used to determine the depth distribution of D after the exposure to D plasma (fluence of 1.3 × 1024 D/m2 and 1.3 × 1025 D/m2 and an exposure temperature of 370 K and 523 K, respectively). Thermal Desorption Spectroscopy (TDS) was used to measure the D desorption spectra. The surfaces of samples exposed to D plasma were also examined in terms of microstructure by scanning electron microscopy. The study has shown that apart from the d-fluence and exposure temperature, the materials’ composition plays a vital role in d-retention, accompanied by blisters and pillar formation. The lowest d-retention was observed for tungsten and the highest in the W-W2C composite. The blisters and pillars were formed in these two materials but not in the WC, which also contains free carbon. At higher D fluence, approximately 15 to 20-times more blisters and pillars were formed in the W-W2C composite than in the tungsten prepared by the same method. The results suggest that the number of defects causing higher d-retention is the highest in W-W2C. On the other hand, the absence of surface irregularities in the WC-C sample after D retention studies indicates that the cause for higher D retention does not lie in the carbides, but, presumably, the microstructural and crystal lattice defects govern the D retention in tungsten-tungsten carbide systems.
Ključne besede: tungsten, (di)tungsten carbide, deuterium, nuclear reaction analysis, thermal desorption spectroscopy
Objavljeno v DiRROS: 03.09.2025; Ogledov: 352; Prenosov: 139
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Ključne besede: rak dojke, medosebne komunikacije, matere in otroci, nespečnost, utrujenost, kognitivne motnje, psihološki nasveti, pomoč, zdravstvene ustanove
Objavljeno v DiRROS: 03.09.2025; Ogledov: 307; Prenosov: 93
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Povzetek: Biathlon activities can have negative effects on the environment due to the processes occurring during shooting, as the biathlon ammunition contains significant amounts of Pb, Cu and Sb. To determine these effects, we looked into the presence of lead-bearing particles in the vicinity of a shooting range in Rudno polje, Pokljuka, in Slovenia. Particles were collected from snow and later analysed using SEM/EDS, where we focused on the lead-bearing particles. These particles are composed of mainly lead or lead oxides/hydroxides with trace presence of Cu and Sb, both of which are commonly related to ammunition used in biathlon shooting and other shooting activities. To confirm that the particles originated from shooting, we compared them with particles taken from an indoor shooting range as dust and residue in ammunition casings. Lead-bearing particles show morphological changes that are caused by high temperatures and pressures during the shooting process.
Ključne besede: atmospheric particles, ammunition residue, SEM/EDS
Objavljeno v DiRROS: 03.09.2025; Ogledov: 341; Prenosov: 102
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Ključne besede: pegilirani liposomalni doksorubicin, doksorubicin, zdravljenje, neželeni učinki zdravil, protitumorne snov, kemoterapija
Objavljeno v DiRROS: 03.09.2025; Ogledov: 294; Prenosov: 91
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Ključne besede: bioindicator, climate, climate change, drought, free-living nematodes, monoculture, plant type, soil micro-fauna
Objavljeno v DiRROS: 03.09.2025; Ogledov: 348; Prenosov: 169
Celotno besedilo (1,24 MB)
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