• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 1999년도 제4차 추계학술대회 초록집
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• pp.96-96
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• 1999

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.301-302
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• 1998

A quadrature RF coil has been developed for 0.3 Tesla permanent MRI systems. The quadrature RF coil is composed of a solenoid coil and a saddle shaped coil. To minimize the coupling ratio between the two coils, each coil is serially connected to a small extra loop. and the small loops are magnetically coupled to each other. By deliberately adjusting relative positions of the small loops, we have decreased the coupling ratio up to -30dB.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.785-788
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• 2005

In this study, micro-scale, high-performance, solenoid-type RF chip inductors were investigated. The size of the RF chip inductors fabricated in this work was $1.0{\times}0.5{\times}0.5mm^3$ The material and shape of the core were 96% $Al_2O_3$ and I-type. The material and number of turn of coil were copper (Cu) and 6. The diameter ($40{\mu}m$) of coil and length (0.35mm) of solenoid were determined by a Maxwell three-dimensional field simulator to maximize the performance of the inductors. High frequency characteristics of the inductance (L) and quality-factor (Q) of developed inductors were measured using an RF Impedance/Material Analyzer (HP4291B with HP16193A test fixture). The inductors developed have inductances of 10.8nH and quality factors of 25.2 at 250MHz, and show results comparable to those measured for the inductors prepared by CoilCraftTm that is one of the best chip inductor company in the world. The simulated data predicted the high-frequency data of the Land Q of the inductors developed well.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.22-25
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• 2001

The research results on the superconducting magnet for whole body MRI are presented. The magnet consists of main coil with 6 solenoid coils, shielding coil with 2 solenoid coils and 6 sets of cryogenic shim coil. The ferromagnetic shim assembly is installed on the inside wall of the room temperature bore for shimming inhomogeneous field components generated due to manufacturing tolerances, installation misalignments and external ferromagnetic materials near the magnet. Also, the magnet is enclosed with the horizontal type cryostat with 80cm room temperature bore to keep the magnet under the operating temperature. The magnetic field distributions within the imaging volume were measured by the NMR field mapping system. Through the test, the central field of magnet was 1.5 Tesla and the field homogeneity of 9.3 ppm has been obtained on 40cm DSV(the diameter of spherical volume) and using this magnet, comparatively good images for human body, fruits and water phantoms have been achieved.

• 한국초전도ㆍ저온공학회논문지
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• 제9권2호
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• pp.7-10
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• 2007

Persistent mode HTS pancake coil has been fabricated using a coated conductor by a "wind-and-flip" method. A coated conductor with the length of 1.2 meters was divided at the center along the length. The sliced coated conductor was wound on a pair of bobbins with a diameter of around 4 cm and two pancake coils connected superconductively without a resistive joint were prepared. By flipping one of the pancake coils, the magnetic field generated by each coil is to be aligned to the same direction and generate meaningful magnetic field while the magnetic fields of two spit coils are canceled without flipping. Permanent current was induced by flowing current to the coil immersed in liquid nitrogen pool using a power supply. A magnetic field of 48.8 Gauss was generated when 20 A of current was flowing in the pancake coils. The "Wind and flip" method can be applied for the fabrication of a long solenoid magnet by winding a sliced coated conductor on a cylindrical bobbin. It is also introduced that the construction of multiple sets of pancake (or solenoid) coils is possible by a "wind-and-flip" method using a wide coated conductor.

• 센서학회지
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• 제9권6호
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• pp.404-415
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• 2000

본 논문에서는 산불에 의한 가공송전선의 열화에 대한 몇 가지 특성들과 비파괴 검사를 다룬다. 노화된 ACSR 도체에 대한 대기부식과 전해부식과 같은 부식기구를 설명한 후에 부식검출에 대해서 기술한다. 솔레노이드 코일의 임피던스 해석을 통하여 와류센서가 도체의 싱한 결함과 국부부식을 검사하는데 유용하게 사용될 수 있음을 확인하였다. 시험 도체를 코일 내부에 삽입한 경우에 센서코일의 임피던스가 변하므로, 산불에 의해 초래된 열화 정도를 측정하는 것이 가능하였다. 인공화염에 의해 열화 된 몇 개의 시료들을 사용하여 인장강도, 신장율과 센서 임피던스가 측정되었다. 화염 기간을 어느 정도 증가시키면, 알루미늄 소선의 인장은 현저하게 감소하기 시작하나 아연도금 강소선은 약간의 아연층이 부식되지만 인장은 초기와 유사하게 유지하였다. 일반적으로 도체의 인장하중이 감소하고 반대로 신장율이 증가하면 센서 임피던스는 감소하는 것을 알 수 있었다. 따라서, 센서의 출력은 도체의 기계적 특성 변화를 나타내므로 이 센서는 산등성이에 가설된 ACSR 도체에 대해 산불로 인한 열화상태를 검출하는데 이용할 수 있다. 결국, 산불에 의한 심한 열화상태에 대한 중요한 정보를 얻는데 솔레노이드 코일을 응용할 수 있다는 것을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.975-980
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• 2001

Like composite material. the coil winding pack of the KSTAR (Korea Superconducting Tokamak Advanced Research) consist of multiphase element such as metallic jacket material for protecting superconducting cable, vacuum pressurized imprepregnated (VPI) insulation, and corner roving filler. For jacket material, four CS (Central Solenoid) Coils, $5^{th}$ PF (Poloidal Field) Coil, and TF (Toroidal Field Coil) use Incoloy 908 and $6-7^{th}$ PF coil, Cold worked 316LN. In order to analyze the global behavior of large coil support structure with coil winding pack, it is required to replace the winding pack to monolithic matter with the equivalent mechanical properties, i.e. Young's moduli, shear moduli due to constraint of total nodes number and element numbers. In this study, Equivalent Young's moduli, shear moduli, Poisson's ratio, and thermal expansion coefficient were calculated for all coil winding pack using Finite Element Method.

• 한국초전도ㆍ저온공학회논문지
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• 제21권3호
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• pp.47-50
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• 2019

The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.

• 전자공학회논문지
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• 제51권10호
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• pp.197-203
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• 2014

신관 안전장전장치는 비행체의 수송, 저장, 취급 중의 안전을 절대적으로 보장하도록 설계되어야 한다. 본 논문에서는 비행체에 적용되는 신관 안전장전장치의 안전성을 증대시키기 위한 솔레노이드 조립체와 솔레노이드 조립체를 구동하기 위한 솔레노이드 구동회로를 포함한 신관 안전장전장치 설계에 대해 기술한다. 솔레노이드 조립체는 신관 안전장전장치에 적용한 추가적인 안전장치로서, 코일 조립체, 복원스프링, 코어 등으로 구성된다. 솔레노이드 조립체의 코어는 평상시에는 1차 안전장치를 구속하고 있어 1차 안전장치가 작동하는 것을 저지해줌으로써 비행체의 취급이나 수송 시 안전을 확보해주게 되며, 발사를 위한 비행체 배터리 전원이 인가 및 활성화되어 신관 안전장전장치에 공급되면, 솔레노이드 구동회로가 코어를 작동시켜 신관 안전장전장치의 1차 및 2차 안전장치를 해제시키는 역할을 한다. 또한, 솔레노이드 구동회로는 비행체 발사 이후, 신관 안전장전장치의 기계적 장전이 완료되어 장전스위치가 turn-on되면 솔레노이드 조립체에 인가되는 전원을 자동 차단시켜 비행 중의 전원 소모량을 줄일 수 있도록 하였다.

• 한국분무공학회지
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• 제19권1호
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• pp.9-14
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• 2014

Performance of DI diesel engine with high-pressure fuel injection equipment is directly related to its emission characteristics and fuel consumption. So, the electro-hydraulic injector for the common-rail injection system should be designed to meet the precise high fuel delivery control capability. Currently, most high pressure injector in use has a needle driven by the solenoid coil energy or the piezo actuator controlled by charge-discharge of output pulse current. In this study, macroscopic spray approaching method was applied under constant volume chamber to research the performance of three different injectors : solenoid, indirect-acting piezo and direct-acting piezo type for CR direct-injection. LED back illumination for Mie scattering was applied on the liquid spray visible of direct-acting piezo injector, including hydraulic-servo type solenoid and piezo-driven injectors. As main results, we found that a direct-acting piezo injector had better a spray tip penetration than hydraulic-servo injectors in spray visualization.