| Project/Area Number |
12555016
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Applied physics, general
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| Research Institution | University of Tsukuba |
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Principal Investigator |
KOSE Katsumi Institute of Applied Physics, Professor, 物理工学系, 教授 (60186690)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥12,400,000 (Direct Cost: ¥12,400,000)
Fiscal Year 2001: ¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2000: ¥9,100,000 (Direct Cost: ¥9,100,000)
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| Keywords | MRI / MR Microscope / permanent magnet / NMR / 勾配コイル / 静磁場 |
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| Research Abstract |
Compact MR microscopes were developed using yokeless permanent magnets. Two different size permanent magnets with 1.0 T central magnetic fields were used ; larger one : gap width ; 60 mm, weight ; 210 kg, size ; 36 cm x 32 cm x 28 cm, homogeneous regions ; 20 mm dsv (13 ppm), and smaller one : gap width ; 41 mm, weight ; 85 kg, size ; 27 cm x 24 cm x 18 cm, homogeneous regions ; 13 mm dsv (13 ppm). The most serious problem in the development of the MR microscopes was temperature drift of the central magnetic field mainly due to the large negative temperature coefficient (-1200 ppm/deg) of the residual magnetic flux density of the Nd-Fe-B magnetic material. Long-term changes of magnet temperatures and Larmor precession frequencies were measured under various thermal conditions of the magnets. As a result, we concluded that the internal NMR locking technique in a time-sharing mode of which time interval was several minutes could compensate the frequency drift and present high-resolution 3D images of chemically fixed animal samples with less than 100 microns cube voxel dimensions.
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