• Journal of Magnetics
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• v.8 no.1
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• pp.70-73
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• 2003

We have developed a new tracking system of jaw movement. The system consists of two permanent NdFeB magnets and 32 elements of two-axial fluxgate sensor array, The two magnets are attached to head portion and front tooth. This system does not need any attachments of the head portion or mouth such as clutch or magnetic field sensor except magnets. The proposed system is applicable for five degree of freedom. Position accuracy within 2]m was achieved. We developed a 3D computer input device by using the above mentioned technique.

• Imaging Science in Dentistry
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• v.32 no.4
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• pp.221-225
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• 2002

Purpose: To evaluate the relationship between internal derangement and osteoarthrosis in the temporomandibular joint (TMJ) using magnetic resonance imaging (MRI). Materials and Methods: One hundred and six MR images of TMJs in 53 patients were evaluated. Disc displacements and osseous changes of the TMJs were assessed. Lateral and rotational disc displacements were also evaluated on coronal images. Results: No significant differences in the frequency of osseous changes of the TMJs between disc displacement with reduction and disc displacement without reduction groups were found. The erosion of the condylar head and the sclerosis of the articular eminence were more frequent in the internal derangement group than in the no disc displacement group. The flattening was the most frequently observed osseous change of both the condylar head and articular eminence. Conclusion : The relationship between internal derangement and osteoarthrosis is obscure, but it is thought that both disorders adversely affect each other.

• Electrical & Electronic Materials
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• v.9 no.1
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• pp.76-92
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• 1996

본 고에서는 대표적인 연자성재료인 Soft 페라이트, 퍼멀로이, 센더스트와 비정질 자성합금계의 특성과 용도를 살펴봄으로써 현재의 기술현황을 알아보고 그 문제점 해결과 특성개선을 위한 연구동향에 대하여 검토하여 보기로 한다. 또한 연자성재료 일반에 걸쳐 용도별 분류와 각 응용기술 분야에서의 기술동향 및 전망에 대하여 소개하고자 한다.

• Journal of the Korean Magnetics Society
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• v.6 no.1
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• pp.7-14
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• 1996

According to demands of high density and wide band magnetic recording systems, a composite MIG head was developed. This head has the sufficient performance for use of a SD VCR : its characteristics are a good recoding performance, a low rubbing noise, a good frequency dependence of efficiency, and a good compatibility with ME tape. In a SD VCR system, the C/N value of a composite MIG head at 20.92MHz was 51 dB.

• Progress in Medical Physics
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• v.28 no.4
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• pp.190-196
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• 2017

For the $ViewRay^{(R)}$ system (ViewRay Inc., Cleveland, OH, USA) which is representative of magnetic resonance (MR) guided radiotherapy machine, it is important to evaluate effectiveness of AAPM's TG-51 protocol and the effect of the magnetic field on absolute dosimetry. In order to measure the absolute dose, MR-compatible chamber and water phantom system manufactured in this study were used. The materials of the water phantom system were plastic of polymethyl methacrylate (PMMA) and non-ferrous materials. Due to the inherent feature of the $ViewRay^{(R)}$, all Co-60 sources are not located at gantry angle of $0^{\circ}$ while being located at gantry angle of $90^{\circ}$. For this reason, absolute dosimetry was performed based on the measurements in solid water phantom (SWP) and water which determine the SWP to water correction factor. For evaluation of output constancy with gantry angle, measurements were made with ionization chamber inserted in cylindrical water-equivalent phantom. For measured doses in water, the values of dose deviation according to a reference dose of 200 cGy for Head 1, Head 2 and Head 3 were -0.27%, -0.45% and -0.22%, respectively. For measured doses in SWP, the values of dose deviation according to a reference dose of 200 cGy for Head 1, Head 2 and Head 3 were -1.91%, -2.07% and -1.84%, respectively. All values of dose measured in SWP tended to be less than those measured in water by -1.63%. With the reference gantry angles of $0^{\circ}$ and $90^{\circ}$, the maximum values of deviation for Head 1, Head 2 and Head 3 were 0.48%, 1.06% and 0.40%, respectively. The measurement agreement is within the range of results obtainable for conventional treatment machines. The low strength of the magnetic field does not affect dose measurements. Using the SWP to water correction factor, absolute doses for $ViewRay^{(R)}$ system can be measured.

• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.262.1-262.1
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• 2007

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.16-16
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• 2003

Purpose： Recently, a major interesting method of fast MR imaging is sensitivity encoding (SENSE) using arrays of multiple receiver coils. In this study, we have designed and implemented a 4-channel head array coil and optimized the structure and arrangement of the coil to improve the performance.

• 한국초전도학회:학술대회논문집
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• 2009.07a
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• pp.71-71
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• 2009

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.47-49
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• 2003

수직 기록 방식은 그 기록 방식의 차이로 인하여 수평 기록 방식에서 쓰여 오던 Write Head의 Design을 적용하였을 경우 기록 밀도를 높이는데 많은 문제점과 낮은 기록 밀도 상승률을 동반하게 된다. 따라서 수직 기록 방식의 자기 기록에서는 수직 기록 방식에 적합한 Write Head의 Design을 적용하여야만 한다. 본 논문에서는 3차원 유한요소법을 이용하여 수직 기록용 Write Head의 한 종류인 SPT Head(Single Pole Tip Head)를 최적 설계하여 그 Write Field의 특성을 분석 제시하였다. 또한 기록 Media의 차이에 따른 기록 특성을 분석하기 위하여 기존 Single Layer 방식과 SUL (Soft Magnetic Under layer)를 사용한 Double Layer 방식을 이용하였을 경우 SUL이 자기 기록에 미치는 영향에 대한 내용을 연구 분석하여 제시하였다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.5
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• pp.38-43
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• 2009

We derive an equation that predicts the induced voltage across the receiving terminals of the three-coil head of a metal detector using a magnetic vector potential approach. We also derive an equation that relates the change of the impedance of the transmitting coil to the properties of the metal. We utilize the results to obtain the optimum spacing between the driving and the receiving coils at which the maximum induced voltage is attained. Further, we determine the position of the metallic object where the voltage reaches its peak. We verify our work by comparing the results with those of a previous work.