| Project/Area Number |
18560405
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Measurement engineering
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
MATUDA Mizushi Muroran Institute of Technology, Faculty of Engineering, Electrical and Electronic Engineering, Professor (20261381)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥300,000)
Fiscal Year 2007: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2006: ¥2,500,000 (Direct Cost: ¥2,500,000)
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| Keywords | SQUID / Signal-noise ratio / Magnetic flux noise / Sensor array / Non destructive evaluation / 非破壊計測 / 超精密計測 / 超伝導材料・素子 / 計測工学 / 電子デバイス・機器 / 生物・生体工学 |
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| Research Abstract |
Measurement of magnetic nanoparticles is a versatile technique to detect target molecules that are labeled with the magnetic particles in various bio-applications. Magnetic particles accumulated in organs can be a marker of certain diseases and the particles/molecules associated with antigen-antibody reaction are detected in immunoassay.
We are developing sensitive detection technique of magnetic nanoparticles based on ac-susceptibility measurement. We have developed a portable SQUID magnetometer for this purpose to measure the current that was detected with an induction coil. The SQUID magnetometer operates as a current meter having a resolution of 16 pA/Hz^<1/2>.
A capsule that. Contained super-paramagnetic nanoparticles was inserted in a solenoid detection coil. A concentric excitation coil was situated around the detection coil. In its original design, two excitation fields of different frequencies are applied to the sample and a harmonic signal of difference frequency is detected^<1>. This is aimed to measure the ac susceptibility of super-paramagnetic particles having nonlinear field-magnetization curve. In this study we detected the third-order higher harmonic of the excitation frequency using a single excitation frequency, which simplified the detection system from the original type.
The harmonic signal was input as a current into the input coil of the SQUID magneto-meter and then coupled as the magnetic flux. The mutual inductance between the input coil and a high-Tc SQUID was 3 nH. As a result, a detection sensitivity of order of 10 ng of Fe_3O_4 particles was achieved at an excitation frequency of 509 Hz.
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