| 1. |
- Korchuganova, O. A., et al.
(author)
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Microstructural evolution of Fe-22%Cr model alloy under thermal ageing and ion irradiation conditions studied by atom probe tomography
- 2016
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In: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115. ; 477, s. 172-177
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Journal article (peer-reviewed)abstract
- Nanostructure evolution during ion irradiation of two thermally aged binary Fee22Cr alloys has been investigated using atom probe tomography. Specimens aged at 500 °C for 50 and 200 h were irradiated by 5.6 MeV Fe ions at room temperature up to fluences of 0.3 × 1015 ions/cm2 and 1 × 1015 ions/cm2. The effect of irradiation on the material nanostructure was examined at a depth of 1 ?m from the irradiated surface. The analysis of Cr radial concentration functions reveals that dense ??-phase precipitates in the 200 h aged alloy become diffuse and thereby larger when subjected to irradiation. On the other hand, less Cr-enriched precipitates in the alloy aged for 50 h are less affected. The CreCr pair correlation function analysis shows that matrix inhomogeneity decreases under irradiation. Irradiation leads to a decrease in the number density of diffuse clusters, whereas in the case of well-developed precipitates it remains unchanged.
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| 3. |
- Thuvander, A., et al.
(author)
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Levels of ochratoxin A in blood from Norwegian and Swedish blood donors and their possible correlation with food consumption
- 2001
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In: Food and Chemical Toxicology. - 0278-6915 .- 1873-6351. ; 39:12, s. 1145-1151
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Journal article (peer-reviewed)abstract
- Blood levels of ochratoxin A were determined in 406 Scandinavian blood donors (206 from Oslo, Norway, and 200 from Visby on the island of Gotland, Sweden), using an HPLC method. In connection with the blood collection, the subjects were asked to fill in a food questionnaire to obtain individual dietary information relevant to ochratoxin A exposure. The mean plasma level of ochratoxin A was 0.18 ng/ml in Oslo and slightly higher, 0.21 ng/ml (P = 0.046) in Visby. There was no correlation between plasma levels of ochratoxin A and the estimated total dietary intake of ochratoxin A based on consumption data and levels in food (retrieved from the literature), neither was the plasma level of ochratoxin A correlated with the total amount of food consumed. However, consumption of several foods, including cereal products, wine, beer and pork, were to some minor degree related to high plasma levels of ochratoxin A. The strongest correlations (correlation coefficient r >0.4; P <0.001) were observed for women in relation to the consumption of beer or medium brown bread. Correlation analysis of combinations of two or more food categories did not result in any statistically significant correlation.
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| 4. |
- Kaczmarski, J., et al.
(author)
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Controlling In-Ga-Zn-O thin films transport properties through density changes
- 2016
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In: Thin Solid Films. - : Elsevier BV. - 0040-6090. ; 608, s. 57-61
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Journal article (peer-reviewed)abstract
- In the following study we investigate the effect of the magnetron cathode current (I-c) during reactive sputtering of In-Ga-Zn-O (a-IGZO) on thin-films nanostructure and transport properties. All fabricated films are amorphous, according to X-ray diffraction measurements. However, High Resolution Transmission Electron Microscopy revealed the a-IGZO fabricated at I-C = 70 mA to contain randomly-oriented nanocrystals dispersed in amorphous matrix, which disappear in films deposited at higher cathode current. These nanocrystals have the same composition as the amorphous matrix. One can observe that, while I-C is increased from 70 to 150 mA, the carrier mobility improves from mu(Hall) = 6.9 cm(2)/Vs to mu(Hall) = 9.1 cm(2)/Vs. Additionally, the increase of I-C caused a reduction of the depletion region trap states density of the Ru-Si-O/In-Ga-Zn-O Schottky barrier. This enhancement in transport properties is attributed to the greater overlapping of s-orbitals of the film-forming cations caused by increased density, evidenced by X-ray reflectivity, at a fixed chemical composition, regardless nanostructure of thin films. (C) 2016 Elsevier B.V. All rights reserved.
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| 5. |
- Kasama, T., et al.
(author)
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Direct observation of doping incorporation pathways in self-catalytic GaMnAs nanowires
- 2015
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In: Applied Physics Reviews. - : AIP Publishing. - 1931-9401. ; 118:5
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Journal article (peer-reviewed)abstract
- Doping mechanisms of Mn in GaAs nanowires (NWs) that have been grown self-catalytically at 600 degrees C by molecular beam epitaxy (MBE) are investigated using advanced electron microscopy techniques and atom probe tomography, Mn is found to be incorporated primarily in the form of non-magnetic tetragonal Ga0.82Mn0.18 nanocrystals in Ga catalyst droplets at the ends of the NWs, while trace amounts of Mn (22 +/- 4 at. ppm) are also distributed randomly in the NW bodies without forming clusters or precipitates. The nanocrystals are likely to form after switching off the reaction in the MBE chamber, since they are partially embedded in neck regions of the NWs. The Ga0.82Mn0.18 nanocrystals and the low Mn concentration in the NW bodies are insufficient to induce a ferromagnetic phase transition, suggesting that it is difficult to have high Mn contents in GaAs even in 1-D NW growth via the vapor-liquid-solid process. (C) 2015 AIP Publishing LLC.
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| 8. |
- Angseryd, Jenny, 1979, et al.
(author)
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Quantitative APT analysis of Ti(C,N)
- 2011
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In: Ultramicroscopy. - : Elsevier BV. - 1879-2723 .- 0304-3991. ; 111:6, s. 609-614
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Journal article (peer-reviewed)abstract
- A specially produced Ti(C,N) standard material, with a known nominal composition, was investigated with laser assisted atom probe tomography. The occurrence of molecular ions and single/multiple events was found to be influenced by the laser pulse energy, and especially C related events were affected. Primarily two issues were considered when the composition of Ti(C,N) was determined. The first one is connected to detector efficiency, due to the detector dead-time. The second one is connected to peak overlap in the mass spectrum. A method is proposed for quantification of the C content in order to establish the C/N ratio. A correction was made to the major C peaks, C at 6 and 12 Da, with the 13C isotopes, at 6.5 and 13 Da, according to the known natural abundance. In addition, a correction of the peak at 24 Da, where C and Ti overlap, is proposed based on the occurrence of single/multiple events for respective element. The results were compared to the results from other techniques such as electron energy loss spectroscopy, chemical analysis and X-ray diffraction. After applying the corrections, atom probe tomography results were satisfactory. Furthermore, the content of dissolved O in Ti(C,N) was successfully quantified. © 2011 Elsevier B.V.
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| 9. |
- Dong, Yan, et al.
(author)
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Atom Probe Tomography Interlaboratory Study on Clustering Analysis in Experimental Data Using the Maximum Separation Distance Approach
- 2019
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In: Microscopy and Microanalysis. - 1435-8115 .- 1431-9276. ; 25:2, s. 356-366
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Journal article (peer-reviewed)abstract
- We summarize the findings from an interlaboratory study conducted between ten international research groups and investigate the use of the commonly used maximum separation distance and local concentration thresholding methods for solute clustering quantification. The study objectives are: to bring clarity to the range of applicability of the methods; identify existing and/or needed modifications; and interpretation of past published data. Participants collected experimental data from a proton-irradiated 304 stainless steel and analyzed Cu-rich and Ni-Si rich clusters. The datasets were also analyzed by one researcher to clarify variability originating from different operators. The Cu distribution fulfills the ideal requirements of the maximum separation method (MSM), namely a dilute matrix Cu concentration and concentrated Cu clusters. This enabled a relatively tight distribution of the cluster number density among the participants. By contrast, the group analysis of the Ni-Si rich clusters by the MSM was complicated by a high Ni matrix concentration and by the presence of Si-decorated dislocations, leading to larger variability among researchers. While local concentration filtering could, in principle, tighten the results, the cluster identification step inevitably maintained a high scatter. Recommendations regarding reporting, selection of analysis method, and expected variability when interpreting published data are discussed.
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| 10. |
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