• 한국지구물리탐사학회:학술대회논문집
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• 2004.08a
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• pp.118-137
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• 2004

Recently underwater geophysical problems for historical relics or UXO's are raised frequently. This study includes the applicabilities and limitations of the recent underwater metal detector and domestic case stories for underwater survey by electrical and magnetic method. Direct or indirect case stories are electrical and vertical magnetic gradiometry surveys beneath Han-river bottom for planning subway tunnel, electrical exploration on lake-bottom, electrical exploration on the tidal flats using high-power transmitter, and borehole three-component magnetic and electromagnetic surveys for detecting the undersea objects. A design of potable real-time, high-speed measurement system using multi-channel array sensors is also introduced here. Further study will be focussed on practical field applications of the fast water-bottom scanning system which is lately required by actual field.

• Investigative Magnetic Resonance Imaging
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• v.23 no.4
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• pp.296-315
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• 2019

Cardiac magnetic resonance (CMR) imaging is widely used in many areas of cardiovascular disease assessment. This is a practical, standard CMR protocol for beginners that is designed to be easy to follow and implement. This protocol guideline is based on previously reported CMR guidelines and includes sequence terminology used by vendors, essential MR physics, imaging planes, field strength considerations, MRI-conditional devices, drugs for stress tests, various CMR modules, and disease/symptom-based protocols based on a survey of cardiologists and various appropriate-use criteria. It will be of considerable help in planning and implementing tests. In addressing CMR usage and creating this protocol guideline, we particularly tried to include useful tips to overcome various practical issues and improve CMR imaging. We hope that this document will continue to standardize and simplify a patient-based approach to clinical CMR and contribute to the promotion of public health.

• Journal of the Korean Magnetics Society
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• v.22 no.4
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• pp.142-146
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• 2012

Records regarding to magnetism in the written Korean history were surveyed. In this article, we depicted how the magnetism (magnet) was understood by the public in the past in the Korea. The records about magnetism could be chronically categorized into three eras; 1) an era of recognizing a magnetic characteristics, 2) era of recognizing a magnetic pole, and 3) era of acquiring a modern knowledge. The written history of the Silla dynasty (BC57-AD935) revealed that a magnet was produced in this era. However, no record about magnet was found in the written history of the Goryo dynasty (918-1392). It was revealed that throughout the Korean history the interest in the magnetism (magnet) was emphasized most in the Josun dynasty (1392-1910). The magnetism (magnet) was most widely exploited in a geomancy. A magnetic compass was used widely to find a merciful direction and place in everyday life. In the era of Josun dynasty, a magnet was exploited as a magnetic compass for a navigation over the sea. An interesting usage of the magnet in the Josun dynasty was found in the pharmaceutical purpose.

• Journal of the Korean Magnetics Society
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• v.19 no.1
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• pp.28-34
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• 2009

Magnetic nanoparticles are widely used for bio-medical applications such as MRI contrast agents, drug-delivery systems, cell separation and hyperthermia, thanks to their unique magnetic properties and physico-chemical characteristics. In the early stage, efforts were focused on synthesis of uniform nanoparticles of desired dimension to achieve targeted, stable functionalities. Recently, it has been of great interest in dispersion of such nanoparitcles in aqueous solution and to render the nanoparticles bio-compatible with biofunctionality on request for utilization in bio-medical fields. In this paper, we survey the research status and give prospective on future work of magnetic nanoparticles for biomedical applications.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.235-235
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• 2011

Lau basin of south Pacific, as an active back arc basin, is promising area bearing seafloor massive hydrothermal deposit that is located in a subduction zone between the Pacific ocean plate and Indo-Australian continental plate. Korea Ocean Research and Development Institute tracked from 2004 to 2006 the hydrothermal activity to the extension of the northeast Lau Basin, targeting seamount. hydrothermal activity by tracking was found hydrothermal evidences. In this study, Marine seismic survey was carried out in the Lau basin seamount of the possibility of hydrothermal deposit. In particular, Marine magnetic survey and seismic survey was carried out at the same time in TA-12 seamount and noise characteristics were found in the seamount. the main process of data processing is Bandpass filter, FK filter, Deconvolution for noise attenuation such backscatter and multiple reflections. the migration is performed to compensate for reflection points followed by seamount of a slope. In this study, bedrock and upper strata could be identified and in the Future, the comparative method with Multi Beam Echo Sounder(MBES) are likely to derive the correct velocity model, the marine magnetic survey results should be considered.

• Korean Journal of Radiology
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• v.24 no.11
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• pp.1102-1113
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• 2023

Objective: To elucidate the use of radiological studies, including nuclear medicine, and biopsy for the diagnosis and staging of prostate cancer (PCA) in clinical practice and understand the current status of PCA in Asian countries via an international survey. Materials and Methods: The Asian Prostate Imaging Working Group designed a survey questionnaire with four domains focused on prostate magnetic resonance imaging (MRI), other prostate imaging, prostate biopsy, and PCA backgrounds. The questionnaire was sent to 111 members of professional affiliations in Korea, Japan, Singapore, and Taiwan who were representatives of their working hospitals, and their responses were analyzed. Results: This survey had a response rate of 97.3% (108/111). The rates of using 3T scanners, antispasmodic agents, laxative drugs, and prostate imaging-reporting and data system reporting for prostate MRI were 21.6%-78.9%, 22.2%-84.2%, 2.3%-26.3%, and 59.5%-100%, respectively. Respondents reported using the highest b-values of 800-2000 sec/mm² and fields of view of 9-30 cm. The prostate MRI examinations per month ranged from 1 to 600, and they were most commonly indicated for biopsy-naïve patients suspected of PCA in Japan and Singapore and staging of proven PCA in Korea and Taiwan. The most commonly used radiotracers for prostate positron emission tomography are prostate-specific membrane antigen in Singapore and fluorodeoxyglucose in three other countries. The most common timing for prostate MRI was before biopsy (29.9%). Prostate-targeted biopsies were performed in 63.8% of hospitals, usually by MRI-ultrasound fusion approach. The most common presentation was localized PCA in all four countries, and it was usually treated with radical prostatectomy. Conclusion: This survey showed the diverse technical details and the availability of imaging and biopsy in the evaluation of PCA. This suggests the need for an educational program for Asian radiologists to promote standardized evidence-based imaging approaches for the diagnosis and staging of PCA.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.47.2-47.2
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• 2016

We introduce a magnetic field survey of the Gould Belt clouds using the James Clerk Maxwell Telescope (JCMT) POL-2: B-fields In STar-forming Region Observations (BISTRO). POL-2 with SCUBA-2 on JCMT is a unique facility, as it is the only facility world-wide that can map the magnetic field within cold dense cores and filaments on scales of ~1000 AU in nearby star-forming regions, such as Taurus and Ophiuchus. It can provide a link between the B-field measured on arc-minute scales by Planck and BLASTPOL and measurements made on arc-second scales by interferometers such as CARMA, SMA, and ALMA. BISTRO was awarded 224 hours toward 16 fields for the next 3 years and started to take data in the 2016A semester.

• Journal of Environmental Impact Assessment
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• v.13 no.5
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• pp.243-250
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• 2004

Recently, concerns about health risks exposed to electromagnetic fields have been brought in the safety of electric power lines. A number of governmental and international organizations have advised to avoid the magnetic field exposure to the schools and residential areas. Some epidemiologic studies showed that electromagnetic fields should not exceed the exposure limits of 2-3mG to the people living near high-voltage transmission lines. In this study, the principles, ranges and survey methods of the assessment for powerfrequency electromagnetic fields were reviewed from the relevant research papers and documents. The ranges of electromagnetic fields were determined from 50m to 100m and have been defined according to the properties of each electric power lines and a new methodology was suggested in this study. It would be necessary to develop and improve specific assessment methods for various high-voltage transmission lines projects.

• Imaging Science in Dentistry
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• v.41 no.4
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• pp.171-175
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• 2011

Gorlin-Goltz syndrome is an infrequent multi-systemic disease which is characterized by multiple keratocysts in the jaws, calcification of falx cerebri, and basal cell carcinomas. We report a case of Gorlin-Goltz syndrome in a 23-year-old man with emphasis on image findings of keratocyctic odontogenic tumors (KCOTs) on panoramic radiograph, computed tomography, magnetic resonance (MR) imaging, and Ultrasonography (US). In this case, pericoronal lesions were mostly orthokeratinized odontogenic cyst (OOC) concerning the MR and US study, which tended to recur less. The aim of this report was to clarify the characteristic imaging features of the syndrome-related keratocysts that can be used to differentiate KCOT from OOC. Also, our findings suggested that the recurrence rate of KCOTs might be predicted based on their association to teeth.

• Journal of The Korean Astronomical Society
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• v.38 no.2
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• pp.283-287
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• 2005

The slow evolution of global magnetic fields and other dynamical processes in atmospheres of CP magnetic stars lead to the development of induced electric currents in all conductive atmospheric layers. The Lorentz force, which results from the interaction between a magnetic field and the induced currents, may modify the atmospheric structure and provide insight into the formation and evolution of stellar magnetic fields. This modification of the pressure-temperature structure influences the formation of absorption spectral features producing characteristic rotational variability of some spectral lines, especially the Balmer lines (Valyavin et al., 2004 and references therein). In order to study these theoretical predictions we began systematic spectroscopic survey of Balmer line variability in spectra of brightest CP magnetic stars. Here we present the first results of the program. A0p star $\Theta$ Aur revealed significant variability of the Balmer profiles during the star's rotation. Character of this variablity corresponds to that classified by Kroll (1989) as a result of an impact of significant Lorentz force. From the obtained data we estimate that amplitudes of the variation at H$\alpha$, H$\beta$, H$\gamma$ and H$\delta$ profiles reach up to $2.4\%$during full rotation cycle of the star. Using computation of our model atmospheres (Valyavin et al., 2004) we interpret these data within the framework of the simplest model of the evolution of global magnetic fields in chemically peculiar stars. Assuming that the field is represented by a dipole, we estimate the characteristic e.m.f. induced by the field decay electric current (and the Lorentz force as the result) on the order of $E {\~} 10^{-11}$ cgs units, which may indicate very fast (< < $10^{10}$ years) evolution rate of the field. This result strongly contradicts the theoretical point of view that global stellar magnetic fields of CP stars are fossil and their the characteristic decay time of about $10^{10}$ yr. Alternatively, we briefly discuss concurring effects (like the ambipolar diffusion) which may also lead to significant atmospheric currents producing the observable Lorentz force.