• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.25-27
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• 2005

This paper deals with the comparison and analysis of brushless DC (BLDC) motor with radial and polar anisotropic plastic magnet. The open-circuit field distributions and back-emf for BLDC motor with polar plastic magnet are established analytically and the results are validated extensively by comparison with finite element (FE) analyses. On the basis of two dimensional (2-D) analytical solutions, this paper predicts open-circuit field characteristics according to design parameters and makes a comparison between BLDC motor with polar plastic magnet and it with radial plastic magnet in terms of required magnet volume and harmonic of air-gap flux density waveform.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.183-185
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• 1998

In this paper, a magnetic circuit of plastic magnet roller for laser printer is presented. The magnetization direction of plastic magnet is decided by the flux distribution of injection mold during the manufacturing process. The injection mold is designed and analysed to fit the design specification. The experiment showed that the flux distribution of a magnet is good agreement of the given specification.

• 한국표면공학회지
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• 제32권3호
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• pp.372-376
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• 1999

The deposited Cu film on the ferrite magnet was more deposited comparing with that on the plastic magnet. The Cu film became thicker on the S pole comparing with that on the N pole in the both of magnets. The thickness and texture coefficient of deposited copper film affected with direction of line of magnetic force. The difference of pole had little or no effect to the texture coefficient of deposited nickel film. The reaction rate on ferrite magnet and S pole was faster comparing with that on plastic magnet and N pole.

• 대한기계학회논문집A
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• 제22권1호
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• pp.64-72
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• 1998

This paper was undertaken to develop the fracture toughness testing method using small and single specimen compared to the conventional method in evaluating elastic-plastic fracture toughness of the superconducting magnet structural material at cryogenic temperature. The elastic-plastic fracture toughness test was conducted by using the unloading compliance method recommended by ASTM E813-89 to accomplish the above purpose. And, the 20% side-grooved 0.5TCT and 1TCT specimens were used to evaluate the fracture toughness by using as possible as miniaturized CT specimen. The unloading compliance method was a very useful method in evaluating elastic-plastic fracture toughness at cryogenic temperature. It could be taken valid fracture toughness values by using 20% side-grooved 0.5TCT specimen recommended by ASTM E813-89.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.125-127
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• 1996

This paper deals with the fabrication of 4 poles anisotropic Sr·ferrite plastic magnets. After Polyamide6 and polyamlde12 are kneaded respectively with Sr·ferrite powder, silane coupling and calcium stearate of lwt% are added for coating and pelleting. The pelleted specimen are injection-moulded under the magnetic field using 4 poles mould. For 4 poles anisotropic Sr·ferrite plastic magnets with polyamide6 as a binder, the surface magnetic flux density distribution is +943.8∼-943.87kG and the deviation is 5.2%, where as with polyamide12, the distribution is +1040.9∼-1040.9kG and the deviation is 5.4%. It shows that both of the magnet distributions are stable. As the results of the experiments, we find 4 poles anisotropic Sr·ferrite magnets have good properties as the materials appropriate for manufacturing magnet type synchronous motors.

• 대한두경부종양학회지
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• 제38권1호
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• pp.69-74
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• 2022

Endochondral pseudocyst of the ear is a rare, benign, non-inflammatory cystic disease. It is known that there are a variety of treatment methods for pseudocyst, which is mainly common in the scaphoid or triangular fossa of the ear. Pseudocyst formation is prevalent in the residual cavity of the ear. So, to prevent a recurrence, a surgical approach is also required, but management through compression is necessary after surgery. Applying a cube magnet to the lesion to press provides patient convenience and facilitates continuous management.

• E2M - 전기 전자와 첨단 소재
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• 제10권5호
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• pp.440-446
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• 1997

This research has been performed for the fabrication of high quality ferrite plastic magnet. The magnetic properties of S $r_{5.9}$F $e_2$ $O_3$ ferrite bonded magnets by injection moulding with a variety of applied magnetic field were investigated. 0.3wt% CaCO3, 0.2wt% $SiO_2$, 0.5wt% $Al_2$ $O_3$and 0.5wt% N $a_2$ $SiO_3$are added in order to improve the magnetic properties of Sr-ferrite plastic magnets during the powder fabrication. For carbon coating on chemical compound specimen, 5wt% polyvinyl alcohol is added, and then calcinated under $N_2$ environment of 12$25^{\circ}C$. The particle size is distributed from 0.9~1.2${\mu}{\textrm}{m}$ which approximates to the single domain. The obtained Sr ferrite powder is well mixed with silane coupling and calcium stearate of 1wt%. Nest, the specimen is pelleted after kneading each of them with polyamidel2 as a binder. When the temperature of injection and mould were 25$0^{\circ}C$ and 8$0^{\circ}C$ respectively at injection pressure of 200kgf/$\textrm{cm}^2$, the degree of orientation was 85.3% under the applied magnetic field of 12kOe. As the results, when the packing density of Sr ferrite powder was 90wt%, the magnetic properties of Sr ferrite bonded magnet were follows : $_{B}$ $H_{c}$=2.41kOe, Br=3.1kG, (BH)$_{max}$=2.21MgOe. Especially, the Sr-ferrite bonded magnet with 10wt% N $d_2$F $e_{14}$B additive were as follows : $_{B}$ $H_{c}$=2.57kOe, Br=3.14kG and (BH)$_{max}$=2.39MGOe.GOe.GOe.GOe.e.

• Advances in pediatric surgery
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• 제13권2호
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• pp.112-118
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• 2007

Ingested foreign bodies are common occurrences in the pediatric population. From October 2002 to April 2006, eight patients (6 male, mean age: $30.9{\pm}14.4$ months, range: 7~45 months) who had ingested metallic foreign bodies, such as bar magnets, coin-type magnets, screws, metal beads, and disk batteries, were selected for foreign body removal using a magnetic device under floroscopic control. A 1-cm-long cylindrical magnet (6 mm in diameter) was placed at the end of a 150-cm-long plastic tube from an IV set. The magnet was passed through the mouth into the stomach. Under fluoroscopic control, the magnet was maneuvered so that it attached to the metallic foreign bodies. The forgeign body was then easily removed by retracting the magnet with the metallic object attached. This procedure was successful in six patients of 8 patients. This procedure is a minimally-invasive and may avoid the use of anesthesics, endoscopy or surgery.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.406-408
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• 2019

자동차에 사용되는 전동식 워터펌프에 적용되는 모터는 CANNED TYPE의 모터 구조이다. 모터의 구동 부품인 로터는 플라스틱 사출물의 격벽 구조 내에 위치하며, 부동액에 침수되어 있는 상태로 회전을 하게 된다. 플라스틱 사출물 격벽 구조 외부에 Stator가 위치되어 Rotor가 회전이 가능하도록 한다. Rotor의 구성은 Magnet와 Core, Shaft로 구성되며, Magnet와 Core의 경우 부품 특성상 수분 침투에 부식되는 재질이기 때문에 부품의 기밀 유지는 매우 중요하다. 차량에 장착된 상태에서는 120도의 환경조건에서 구동이 가능하여야 하며, 내부압력이 1 Bar 이상의 압력에도 누수가 없어야 한다. 본 논문에서는 이 조건을 만족하여 개발된 전동식 워터펌프의 불량을 검사하기 위하여 헬륨을 이용한 Leak 검사 자동화 시스템을 설계 및 구현하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.10-13
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• 2021

The method of removing micro-plastics from sea water has been developed using electro-magnetic force. Plastics are difficult to decompose and put a great load on the marine environment. Especially a plastic with a size of 5 mm or less is defined as micro-plastic and are carried by ocean currents over long distances, causing global pollution. These are not easily decomposed in the natural environment. The Lorentz force was generated in simulated sea water and its reaction force was applied to the micro-plastic to control their motion. Lorentz force was generated downward and the reaction force to the plastics was upward. The plastic used in the experiment was polystyrene with a diameter of 6 mm, and the density was 1.07 g/cm³. The polystyrene sphere levitated at the current density of 0.83 A/cm² and the external field of 0.87T. The particle trajectory calculation was also made to design separation system using superconducting magnet.