• Elastomers and Composites
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• 제51권1호
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• pp.38-42
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• 2016

For improving the heat loss of a refrigerator around door gasket, it is very important to reduce the amount of rubber magnet used, of which thermal conductivity is much higher than the plastics, and enhancing the magnetic properties of rubber magnet itself is crucial for this. In the present study, therefore, a relationship between the optimum conditions of rubber magnet fabrication process and raw material compositions in the ferrite powder/CPE binder compounds was investigated for finding a way to enhance the magnetic properties of rubber magnet. Magnetic attraction forces of a sample rubber magnet was measured as function of distance, and thermal properties of the sample ferrite powder/CPE binder compound were analyzed with TG/DTA thermal analyzer. As a results, a rubber magnet strip with enhanced magnetic properties was expected to be fabricated, of which raw material compound was prepared by compounding with higher ferrite magnetic powder concentration.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.834-839
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• 2007

This paper investigates the distortion of magnetic field of a brushless DC (BLDC) motor due to deformed rubber magnet. Global or local deformation of rubber magnet in the BLDC motor is mathematically modeled by using the Fourier series. Distorted magnetic field is calculated by using the finite element method, and unbalanced magnetic force are calculated by using the Maxwell stress tensor. The first harmonic deformation in the global deformation of rubber magnet generates the first harmonic driving frequency of the unbalanced magnetic force, and the rest harmonic deformations of rubber magnet except the harmonic deformation with multiple of common divisor of pole and slot introduces the driving frequencies with multiple of slot number ${\pm}1$ to the unbalanced magnetic force. However, the harmonic deformation with multiple of common divisor of pole and slot does not generate unbalanced magnetic force due to the rotational symmetry. When the rubber magnet is locally deformed, the unbalanced magnetic force has the first harmonic driving frequency and the driving frequencies with multiples of slot number ${\pm}1$.

• 에너지공학
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• 제23권4호
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• pp.240-246
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• 2014

본 연구는 냉장고의 본체와 냉장고 문 사이에 있는 가스켓 주위에 냉장고 본체와 문의 밀착을 위해 설치하는 고무자석의 재질과 형상을 변경하여 냉장고 열손실을 개선하는 것을 목적으로 하였다. 냉동실과 냉장실을 포함한 냉장고 수평 단면에 대하여 가스켓 주위에 대한 열전달 해석을 수행하였다. 본 연구를 통해 가스켓 내부와 Hotline 옆의 고무자석의 열전도율을 기존 10W/mK에서 1W/mK로 변화하면 냉장고 열손실이 약 7% 저감되고 Hotline 옆의 고무자석을 제거하고 대신에 철판을 설치하면 냉장고의 열손실을 약 17% 저감 되는 것을 알 수 있었으며 Hotline 옆의 고무자석을 제거하고 대신에 철판을 설치하는 것이 냉장고 열손실에 큰 효과가 있음을 알 수 있었다.

• 한국강구조학회 논문집
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• 제28권4호
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• pp.223-229
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• 2016

이 연구에서는 고무 스프링과 자력마찰을 조합한 스마트 댐퍼의 동적 실험을 수행하여 스마트 댐퍼의 깃발모양 (flag-shaped) 거동을 확인하고자 하였다. 스마트 댐퍼 동적실험을 수행하기 위하여, 네오디뮴 (NdFeB) 자석을 사용하였으며 $50mm{\times}50mm{\times}25mm$ ($B{\times}L{\times}H$)의 크기를 사용하였다. 또한 폴리우레탄 고무를 사용하였으며 길이 80mm 외경 80mm 내경 20mm의 크기의 원주형 고무스프링을 사용하였다. 동적 실험에서 자석의 개수와 진동수를 제어하여 수행하였으며, 자석의 개수는 0, 4, 8, 12개의 순서로 증가하였으며, 이는 자력 마찰력이 증가함을 의미하였다. 진동수는 0.1부터 2.0Hz까지 증가시키면서 진행하였다. 실험의 진행은 고무 스프링이 장착되지 않은 자력마찰 댐퍼의 자력 마찰력 평가 실험, 고무 스프링의 기압축량 평가 실험 및 최종적으로 자력 마찰력과 기압축 고무스프링이 합성된 스마트 댐퍼의 동적 실험 순서로 진행하였다. 실험 결과를 통하여 스마트 댐퍼의 깃발모양 거동을 평가하고 에너지 소산능력, 감쇠비를 평가하여 스마트 댐퍼로서의 성능을 확인하였다.

• 마이크로전자및패키징학회지
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• 제31권3호
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• pp.18-23
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• 2024

나노임프린트 리소그래피(Nanoimprint lithography, NIL)는 저렴한 공정비용으로 고해상도 패턴을 제조할 수 있는 장점을 가지고 있기 때문에 마이크로 크기부터 나노스케일까지 패턴을 형성하는데 많이 사용되고 있다. 그러나, 대부분의 NIL 공정 기술은 기본적으로 임프린트용 레지스트 사용이 필요하고, 자외선, 열과 같은 외적인 요소 또한 필요로 하기 때문에, 타겟 소재를 패터닝하기 위해서 식각공정 또는 금속 증착 등의 추가적인 후공정이 요구된다. 그리고, 유연 필름이나 굴곡이 있는 소재를 패터닝 하기에 어려움이 있다. 본 연구에서는, 유연한 자성고무 복합재(rubber magnet composite, RMC) 기판 표면에 마이크로/나노 수준의 패턴을 상온에서 식각 공정 없이 형성할 수 있는 극압 임프린트 리소그래피(extreme pressure imprint lithography, EPIL) 공정을 소개하고자 한다. EPIL 기술은 금속, 고분자, 세라믹과 같은 다양한 재료의 표면에 직접적이고 영구적인 변형을 통해 초미세 구조물을 대면적으로 형성할 수 있는 공정으로서, 본 연구에서는 RMC 필름에 적용하여 서브 마이크로 크기의 패턴 형성이 가능함을 보여준다. 우리는 스트론튬계 페라이트와 염소화폴리에틸렌으로 구성된 유연한 RMC 기판 표면에 마이크로/나노 스케일의 다양한 패턴 크기 및 형상을 갖는 균일한 구조물을 형성할 수 있는 공정 및 결과물을 보여주고자 한다. RMC 필름 표면 상 미세한 패턴구현이 가능한 EPIL 공정은 미세한 자기 방향의 변화 및 제어를 요구하는 첨단 전자기소자 부품 제조에 널리 적용될 수 있을 것으로 기대한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권1호
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• pp.41-55
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• 2015

This study is proposed a new hybrid mount having a moving-magnet type electromagnetic actuator to reduce the vibration transmitted from naval shipboard equipment to the structure of the ship's hull. Optimal design specifications are determined through experimental analysis. The detailed design of the hybrid mount is determined through several design steps with electromagnetic numerical analysis using Maxwell Software(S/W). The hybrid mount that combines a rubber mount and an electromagnetic actuator has a fail-safe function for shock resistance. The mount is fabricated and tested using a universal testing machine to evaluate the design specifications. Finally, numerical simulation of the hybrid mount is performed to confirm control performance and applicability.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권5호
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• pp.315-320
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• 2000

This paper presents the fabrication and test of a micropump with an electromagnetic actuator and a pair of aluminum flap valves. The actuator consists of a solenoid coil, a permanent magnet and an actuator diaphragm. The actuator diaphragm is fabricated by the spin coating of silicone rubber. The valve are passive ones and are fabricated by micromachining. The deflection of the fabricated actuator diaphragm is measured with a laser vibrometer. The deflection of the actuator diaphragm is proportional to the input current. The measured deflection of the fabricated diaphragm is $400 \mum$,/TEX> when the input is 118 mApp, and the cut-off frequency is 50 Hz. The maximum flow rate of the fabricated micropump with the electromagnetic actuator is about 5$0 \muell/min$ at 5 Hz when the input current and the duty ratio of the square was are 118 mApp and 50%, respectively.

• 한국소음진동공학회논문집
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• 제24권3호
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• pp.236-246
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• 2014

This paper presents a hybrid rubber mount with magnet to isolate effectively the vibration in vehicle, forklift, and so on. The hybrid mount does not have any controller of the magnetic force. Dynamic stiffness of the mount is reduced by only magnetic suction according to the applied magnetic field and damping coefficient increased. Performance of conventional rubber mount with using electromagnet has been investigated by MTS Tester. The governing equation of the hybrid mount was derived and verified by comparison with experimental and theoretical results. The equation can be used practically and usefully in the design of the mount and analysis of the mounting system. The hybrid mount provides excellent performance in vibration isolation and its structure is very simpler than active with controller and a semi-active mount with a functional fluid. Furthermore, production cost of the mount using permanent magnets is very lower than that of the active mount with electromagnets. Therefore, commercial potential of the mount is very high.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.873-878
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• 2008

Doosan Mecatec has developed alignment system for Organic Light-Emitting Diode (OLED) display production using large size substrate. In the present article, The alignment system between the substrate and the mask, which is a core technology for producing the OLED product using the fourth-generation substrate with $730{\times}920mm^2$ or more, will be described by dividing into a substrate loader, a magnet unit, a CCD camera, etc. The substrate loader is optimized through the simulation where the central portion of the substrate droops by about 1.5mm by clamping each of a long side (920mm direction) and a short side (730mm direction) thereof by 6 point and 4 point. A magnet unit using a sheet type of rubber magnet is constituted and a CCD camera model with the specifications capable of minimizing the errors between a clear image and the same image is selected. The system to which an upward evaporation technique of small molecular organic materials will be applied has been developed so that repeatability and position accuracy becomes ${\pm}1{\mu}m$ or less using an UVW type of stage. Also, the vision accuracy of the CCD camera becomes ${\pm}1{\mu}m$ or less and the align process TACT becomes 30sec. or less so that the final alignment accuracy between the substrate and the mask becomes ${\pm}3{\mu}m$ or less. In order to meet an extra-large glass substrate, an evaporation system using an extra-large AMOLED substrate has been developing through a vertical type of an alignment system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.121-126
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• 2001

This paper presents the experimental study for the reduction of transmitted shock waves in smart structures incorporating MR insert. MR fluid is filled within the two aluminum layers and two piezoceramic disks are embedded on the host plate as a transmitter and a receiver of the shock wave. Pulse wave generated by the transmitter is transmitted to the receiver through the MR insert and the plate. By applying magnetic field to the MR insert, the amplitude of the transmitted shock wave is reduced remarkably. The attenuation performance is tested by changing the applied magnetic field on MR inserts in two ways: by changing angle of permanent rubber magnet from 90 to 5 with 5 decrements, by using electromagnet in which magnetic field is controllable. The propagating wave speed of MR insert is also investigated.