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Ling L.-G.,Finnish Center for Radiation and Nuclear Safety
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2014

The end-corner reflection test system is built basing on Z-scan ultrasonic detector, standards and reference blocks, as well as UltraVision ultrasonic signal acquisition and analysis software. Respectively, the end-corner reflection of 45°, 60° and 70° Ultrasonic transducers is tested. First, all reflection echo signal are sampled and analysed, and then the end-corner reflection echo signals is isolated basing on ultrasonic propagation law and the end-corner reflection waves mode conversion law. The relative reflectance of the above signal is computed at last. Test results show that 45° transverse wave transducer end-corner reflection close to the total reflection. The clutter from the end-corner reflection of longitudinal wave transducer is more than the transverse wave transducer. ©, 2014, Jiliang Xuebao/Acta Metrologica Sinica. All right reserved. Source

Li Y.-X.,Beijing Normal University | Zhang X.-L.,Beijing Normal University | Li W.,Finnish Center for Radiation and Nuclear Safety | Lu X.-F.,Beijing Normal University | And 2 more authors.
Environmental Monitoring and Assessment | Year: 2013

To understand the residues and ecological risks of veterinary antibiotics (VAs) in animal faeces from concentrated animal feeding operations in northeastern China, 14 VAs were identified by high performance liquid chromatography, and the preliminary risks of six antibiotics were assessed using the hazard quotient (HQ). The investigated VAs occurred in 7.41 to 57.41 % of the 54 samples, and the levels ranged from 0.08 to 56.81 mg kg-1. Tetracyclines were predominant with a maximum level of 56.81 mg kg-1 mostly detected in pig faeces. Sulfonamides were common and detected with the highest concentration of 7.11 mg kg-1. Fluoroquinolones were more widely detected in chicken faeces rather than in pig or cow faeces, which contained the dominant antibiotic enrofloxacin. In comparison, the residue of tylosin was less frequently found. The risk evaluations of the six antibiotics revealed that tetracyclines, especially oxytetracycline, displayed the greatest ecological risk because of its high HQ value of 15.75. The results of this study imply that multiple kinds of VAs were jointly used in animal feeding processes in the study area. These medicine residues in animal faeces may potentially bring ecological risks if the animal manure is not treated effectively. © 2012 Springer Science+Business Media B.V. Source

Lehto J.,University of Helsinki | Vaaramaa K.,University of Helsinki | Vaaramaa K.,Finnish Center for Radiation and Nuclear Safety | Leskinen A.,University of Helsinki | Leskinen A.,CEA Saclay Nuclear Research Center
Journal of Environmental Radioactivity | Year: 2013

Profiles of podzolic soil from boreal forests were sampled from eight sites in Finland and the distribution of 137Cs in the soil layers was determined. In addition, 239,240Pu and 241Am were determined from two soil profiles taken at one sampling site. Inventories of 137Cs in the soil profiles varied between 1.7 kBq/m2 and 42 kBq/m2, reflecting known variation in 137Cs fallout from the Chernobyl accident. The highest proportions of the radionuclides were found in the organic layer at a depth of less than 5 cm, which on average contained 47% of 137Cs, 76% of 239,240Pu and 79% of 241Am. In the litter, clearly higher proportions of 137Cs were found compared to 239,240Pu and 241Am, probably indicating its more effective recycling from the organic layer back to the surface. Only very minor proportions of 137Cs were recorded below 20 cm. The concentration of 137Cs in the soil profiles could be approximated with a declining logarithmic trend. The activity concentrations of 137Cs were determined for six wild mushroom species and three wild berry species at two sites, as well as the aggregated transfer factors and the distribution of 137Cs between their various parts. In addition, 239,240Pu and 241Am were determined in one mushroom and three berry species at one site. Very high concentrations of 137Cs, up to 20 kBq/kg (d.w.), were found in mushrooms, and their transfer factors were between 0.1 m2/kg and 1.0 m2/kg. In berries, the transfer factors were an order of magnitude lower. 137Cs accumulated more in the caps of mushrooms and in the fruits of berries than in other parts. Transfer factors for 239,240Pu and 241Am were two to three orders of magnitude lower than those of 137Cs. © 2012 Elsevier Ltd. Source

Wang M.,Sichuan University | Liu R.,Finnish Center for Radiation and Nuclear Safety | Yang S.,Sichuan University
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

An optimal synthesis method of adjustable spherical four-bar mechanisms for multi-function generation was put forward. Different functions can be generated by the same mechanism through adjusting the length of the connecting frame poles. Based on the function relation between the input angle and the output angle of the spherical four-bar mechanism, the optimization model was established. The objective function was given with the aim of minimizing the maximum of the absolute structural error, and the constraints were given to ensure the crack existed and that the mechanisms have good transmission quality. After this, the immune genetic algorithm was chosen for multi-function generation of adjustable spherical four-bar mechanisms. The result of the synthesis example verified the effectiveness of the proposed method. Source

Ogawa T.,Research Group for Radiation Protection | Morev M.N.,Finnish Center for Radiation and Nuclear Safety | Sato T.,Research Group for Radiation Protection | Hashimoto S.,Research Group for Radiation Protection
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2013

Fragmentation reaction cross-sections of lead bombarded by carbon ions below 400 MeV/u are measured and compared with those simulated with Monte-Carlo radiation transport code PHITS to pinpoint the problems of simulation based on the quantum molecular dynamics model and the statistical decay model. Cross-sections for 32 fragments from A = 24 to 85 and those from A = 121 to 175 are measured within a reasonable uncertainty. Contribution of secondary particles to production of measured fragments are generally less than 20%. Comparison shows production cross-sections for fragments from A = 20 to 60 and those from A = 110 to 130 are underestimated by one order of magnitude. Further simulation shows production of each group of fragments in simulation are attributed to evaporation of fission fragments and to evaporation of highly excited prefragments, respectively. The lower the energy is, the more this trend is pronounced. Observed underestimation indicates presence of nuclear reaction mechanisms not considered in the current simulation such as multi-fragmentation. © 2013 Elsevier B.V. All rights reserved. Source

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