• Journal of the Korean earth science society
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• v.43 no.5
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• pp.604-617
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• 2022

Sea surface temperature (SST) is a key variable that can be used to understand ocean-atmosphere phenomena and predict climate change. Satellite microwave remote sensing enables the measurement of SST despite the presence of clouds and precipitation in the sensor path. Therefore, considering the high utilization of microwave SST, it is necessary to continuously verify its accuracy and analyze its error characteristics. In this study, the validation of the microwave global precision measurement (GPM)/GPM microwave imager (GMI) SST around the Northwest Pacific and Korean Peninsula was conducted using surface drifter temperature data for approximately eight years from March 2014 to December 2021. The GMI SST showed a bias of 0.09K and an average root mean square error of 0.97K compared to the actual SST, which was slightly higher than that observed in previous studies. In addition, the error characteristics of the GMI SST were related to environmental factors, such as latitude, distance from the coast, sea wind, and water vapor volume. Errors tended to increase in areas close to coastal areas within 300 km of land and in high-latitude areas. In addition, relatively high errors were found in the range of weak wind speeds (<6 m s^-1) during the day and strong wind speeds (>10 m s^-1) at night. Atmospheric water vapor contributed to high SST differences in very low ranges of <30 mm and in very high ranges of >60 mm. These errors are consistent with those observed in previous studies, in which GMI data were less accurate at low SST and were estimated to be due to differences in land and ocean radiation, wind-induced changes in sea surface roughness, and absorption of water vapor into the microwave atmosphere. These results suggest that the characteristics of the GMI SST differences should be clarified for more extensive use of microwave satellite SST calculations in the seas around the Korean Peninsula, including a part of the Northwest Pacific.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.141.2-141.2
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• 2007

• Proceedings of the Korean Magnestics Society Conference
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• 2003.06a
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• pp.88-89
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• 2003

During the past decade, giant magnetotransport phenomena such as giant magetoresistance (GMR) in thin films and in manganese perovskites, and, giant magnetoimpedance (GMI) in soft magnetic amorphous ribbons, have brought much interest in the basic physical understanding and their applications as magnetic recording heads and in magnetic sensors technology. Among the parameters required for the quality of a magnetic sensor, temperature dependences of GMR and GMI profiles are playing an important role. In the present work, we have studied temperature dependences of the longitudinal permeability and giant magnetoimpedance effect in $Co_{70}$F $e_{5}$S $i_{15}$ N $b_{2.2}$C $u_{0.8}$ $B_{7}$ amorphous ribbons expecting as a promising candidate in the domain of magnetic sensors.rs.rs.rs.s.

• Journal of Magnetics
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• v.9 no.2
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• pp.47-51
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• 2004

Giant magneto-impedance (GMI) effect in zero-magnetostrictive Co-based amorphous ribbons samples in their as-quenched and stress-released states as well as with intentionally induced magnetic anisotropy were investigated. Magnetic and impedance properties of the samples exhibiting different anisotropy were compared and the optimum operation conditions for the studied samples from the view-point of their utilization as a sensor element have been determined. A design of a model of magnetic field sensor and characteristics of the constructed prototype are presented.

• Journal of Sensor Science and Technology
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• v.15 no.2
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• pp.77-83
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• 2006

A monitoring apparatus for pulse shapes of human heartbeats has been developed using an amorphous MI(Magnetic Impedance) sensor. The pulse shapes are successfully obtained from voltage signals due to the variations of magnetic impedance in the amorphous MI sensor, which is attached to a patient's wrist. This voltage signal was fed into a signal processing module to extract the pulse shapes of heartbeats. The signal processing module, which is proposed to detect a weak variations of impedance in MI sensor under a noisy measurement environment, consists of a high frequency current source, an amplifier stage and a synchronous detection circuit. To evaluate the characteristics of a newly developed apparatus, various experiments were performed. The experimental results show that the developed apparatus could be used as a diagnosis tool for traditional Korean medicine with further systematic clinical studies.

• Journal of Magnetics
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• v.15 no.4
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• pp.194-198
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• 2010

In our present work, we developed a GMI (giant magnetoimpedance) sensor system to detect magnetic fields in the milli gauss range based on the asymmetric magnetoimpedance (AGMI) effect in Co-based amorphous ribbon with self bias field produced by field-annealing in open air. The system comprises magnetoimpedance sensor probe, signal conditioning circuits, A/D converter, USB controller, notebook computer, and program for measurement and display. Sensor probe was constructed by wire-bonding the cobalt based amorphous ribbon with dimensions $10\;mm\;{\times}\;1\;mm\;{\times}\;20\;{\mu}m$ on a printed circuit board. Negative feedback was used to remove the hysteresis and temperature dependence and to increase the linearity of the system. Sensitivity of the milli gauss meter was 0.3 V/Oe and the magnetic field resolution and environmental noise level were less than 0.01 Oe and 2 mOe, respectively, in an unshielded room.