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STUDY ON X-RAYS AND NEUTRONS LEAKED FROM A 45 MeV ELECTRON LINAC FACILITY
Sadashi, Sawamura,Masatoshi, Kitaichi,Ichiro, Nojiri,Takuma Yamada,Junichi, Kaneko,Teruko, Sawamura 대한방사선 방어학회 2001 방사선방어학회지 Vol.26 No.3
Spatial and time distributions of x-rays and neutrons from Hokkaido University 45 MeV electron linac facility were measured and compared with the calculation. In the calculation, x-rays in a Pb-target were evaluated using the EGS-code. The x-rays and the neutrons from the target to the facility building boundary and skyshine processs outside the facility building were simulated with the EGS and the MCNP respectively.
Hasib Maruf Mohammad,Yamada Kentaro,Hoshino Masatoshi,Yamada Eiji,Tamai Koji,Takahashi Shinji,Suzuki Akinobu,Toyoda Hiromitsu,Terai Hidetomi,Nakamura Hiroaki 대한척추외과학회 2021 Asian Spine Journal Vol.15 No.4
Study Design: Retrospective radiological comparative design.Purpose: To investigate whether conventional magnetic resonance imaging (MRI) could substitute three-dimensional (3D)-MRI for the calculation of the foraminal stenotic ratio (FSR) and clarification of which patients can be assessed more accurately using 3D-MRI.Overview of Literature: Previous studies have indicated that 3D-MRI is useful for diagnosing lumbar foraminal stenosis. The FSR obtained using 3D-MRI, described as the ratio of stenosis length, characterized by perineural fat obliteration, to the length of the entire foramen, could indicate the stenosis severity; however, this method is time-consuming and expensive. The FSR also can be calculated using conventional MRI.Methods: We investigated 154 foramina at L5–S1 in 77 patients. All the patients had degenerative lumbar disorders and had undergone both conventional MRI and 3D-MRI during the same visit. Differences between the FSRs calculated from conventional and 3D-MRI reconstructions and any correlations with the plain radiography findings were assessed.Results: In foramina that had a FSR of <50% on conventional MRI, the difference between the FSR obtained using conventional MRI and 3D-MRI was 5.1%, with a correlation coefficient of 0.777. For foramina with a FSR ≥50% on conventional MRI, the difference was 20.2%, with a correlation coefficient of 0.54. FSR obtained using 3D-MRI was significantly greater in patients who required surgery than in those who were successfully treated with conservative methods (88% and 42%, respectively). Segments with spondylolisthesis or lateral wedging showed higher FSRs than those without these conditions on both types of MRI.Conclusions: FSRs <50% obtained using conventional MRI were sufficiently reliable; however, the results were inaccurate for FSRs ≥50%. Patients with high FSRs on 3D-MRI were more likely to require surgical treatment. Therefore, 3D-MRI is recommended in patients with suspected stenosis detected using conventional MRI or plain radiographs.
STUDY ON X-RAYS AND NEUTRONS LEAKED FROM A 45 MeV ELECTRON LINAC FACILITY
Sawamura, Sadashi,Kitaichi, Masatoshi,Nojiri, Ichiro,Yamada, Takuma,Kaneko, Junichi,Sawamura, Teruko Korean Association for Radiation Protection 2001 방사선방어학회지 Vol.26 No.3
Spatial and time distributions of x-rays and neutrons from Hokkaido University 45 MeV electron linac facility were measured and compared with the calculation. In the calculation, x-rays in a Pb-target were evaluated using the EGS-code. The x-rays and the neutrons from the target to the facility building boundary and skyshine process outside the facility building were simulated with the EGS and the MCNP respectively.
Effect of Fertilizer with Low Levels of Potassium on Radiocesium-137 Decontamination
강동진,Hirofumi Tazoe,Yasuyuki Ishii,Katsunori Isobe,Masao Higo,Masatoshi Yamada 한국작물학회 2018 Journal of crop science and biotechnology Vol.21 No.2
Potassium (K) fertilizer closely affects both above-ground biomass production and radiocesium-137 (137Cs) uptake by plants from Cs-contaminated soil. Here we investigated the effects of low levels of K on aboveground biomass, 137Cs concentration, and 137Cs removal ratio (CR) using Napier grass (Pennisetum purpureum Schum.). Experimental plots fertilized with either 2 g K (20% K) or 6 g K (60% K) per m2 were compared with that with no K fertilization (0% K) under low-, medium-, and high-density planting conditions. As a result, with increasing amounts of K fertilizer, the aboveground biomass of Napier grass tended to increase, and the 137Cs concentration significantly decreased. The greatest CR was observed at the plot fertilized with 20% K and with plants grown under highly dense conditions. CR was positively correlated with biomass in all the experimental plots. Moreover, a positive correlation between CR and 137Cs concentration was found only at low levels of K application (0% and 20% K). In the present study, the application of 20% K produced more aboveground biomass and smaller decreases in 137Cs concentration in Napier grass compared with those with 0% K application; therefore, applying a fertilizer with low levels of K, such as 20% K, is better for 137Cs decontamination than applying 0% or 60% K fertilizer.
High-energy Magnetic Excitations in Underdoped La1.90Sr0.10CuO4
Kentaro Sato,Masato Matsuura,Masaki Fujita,Ryoichi Kajimoto,Sungdae Ji,Kazuhiko Ikeuchi,Mitsutaka Nakamura,Yasuhiro Inamura,Masatoshi Arai,Masanori Enoki,Kazuyoshi Yamada 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12
We measured the magnetic excitations in underdoped (UD) La1.90Sr0.10CuO4 by using inelasticneutron scattering over a wide energy range. We succeeded in observing the high-energy excitationsup to '160 meV. Hour-glass-like magnetic excitation, which is commonly seen in the superconductingphase of cuprate oxides, was confirmed. The Ecross (the energy where the dispersion is closestto the ( 12 , 12 ) reciprocal position) of 40 meV follows a linear relation between Ecross and the dopedhole concentration in the UD region. From the dispersion of high-energy excitations above Ecross,we successfully found an effective nearest neighbor interaction (Jeff ) of 102 ± 2 meV. This Jeff issmaller than the nearest neighbor interaction J(=132 meV) in the parent compound La2CuO4,indicating a reduction of Jeff by hole-doping.