• 한국전자파학회논문지
• /
• 제18권6호
• /
• pp.648-655
• /
• 2007

본 논문에서는 유도결합을 이용한 RFID 시스템에서 주변의 RF 잡음의 영향을 감소할 수 있는 이중 코일 안테나를 새로이 제안하고 실험하였다. 이중 코일 안테나는 동일한 구조의 코일 2개가 직렬로 연결되어 있으며 두 코일에 유도되는 잡음 전압의 크기가 같고 극성이 반대가 되어 서로 상쇄되도록 고안된 구조이다. RFID 리더에 이중 코일 안테나를 사용한 경우에 단일 코일 안테나에 비하여 RF 유도 잡음이 약 15 dB 감소하였다.

• 한국초전도ㆍ저온공학회논문지
• /
• 제3권1호
• /
• pp.16-21
• /
• 2001

Bubble behavior is studied with an electrode system which consists of coaxial spiral coil-to-cylindrical electrode with an insulation barrier and spacers and is immersed in liquid nitrogen for simulation of insulation environments in high temperature superconducting(HTS) coils The results show that the bubble behavior Is affected severely by electric field: (1) under low applied voltage bubbles rise by buoyancy, but at higher applied voltage they are trapped in a lower electric field region below the coil electrode, and (2) the trapped bubble flows along the downside of coil electrode if no obstruction is in a groove between coil turns. but it splashes out of the groove after its growing if the obstruction such as spacer-exists.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권5호
• /
• pp.333-338
• /
• 1999

Thin film inductors of $10 mm \times 10 mm$ with inner coil type of 14 turns were fabricated by sputtering, photo-masking, and etching processes. Their characteristics of impedances and annealing after were investigated. The properties of impedances of the thin film magnetic core inductors with inner coil type were improved by magnetic field annealing due to the removal of residual stress and the improvement magnetic properties of magnetic films. But the characteristics of frequency of the thin film magnetic core inductors were not improved by magnetic field annealing due to properties of the spiral pattern and inner coil type. The thin film magnetic core inductor annealed by uniaxal field annealing method showed an inductance of 1000 nH and resistance of$ 6 \Omega$ of 1 at 2 MHz.

• Tuberculosis and Respiratory Diseases
• /
• 제51권1호
• /
• pp.53-58
• /
• 2001

기관지 동맥 색전술에도 불구하고 반복되는 대량 객혈을 보이는 동공성 폐결핵 환자에서 나선형 CT를 이용하여 Rassmusen 동맥류의 위치 및 크기를 비교적 정확히 진단하여 coil 이용한 경도관 폐동맥 색전술로 성공적으로 지혈 시킨 사례를 경험하였기에 보고하는 바이다.

• 소성∙가공
• /
• 제23권7호
• /
• pp.431-438
• /
• 2014

For electromagnetic forming(EMF) the most important feature is a forming coil which creates the electromagnetic force(Lorentz force), using current density and a magnetic field. Most previous papers have concentrated on the final configuration of the blank or the efficiency of EMF process. Studies focused on the design parameters affected by the forming coil performance have not been conducted. In order to design a suitable forming coil for an object, the current study uses LS-DYNA EM-Module to not only optimize the coil but also to examine the effect of coil performance. By this method a suitable forming coil was made and tested to determine whether or not good formability was achieved in a free bulge test Numerical analysis was also used. The workpiece was Al 1100-O with a thickness of 1.27mm and the coil was made from copper CW004A, which has good electrical conductivity and is suitable for electrical components.

• 대한기계학회논문집B
• /
• 제25권12호
• /
• pp.1676-1683
• /
• 2001

An experimental study on condensation heat transfer characteristics of helically coiled spiral tubes was performed. The refrigerant is R-113. A refrigerant loop was established to measure the condensation heat transfer coefficients. Experiments were carried out uniform heat flux of 15 kw/m$^2$, refrigerant quality of 0.1∼0.9, curvature ratio of 0.016, 0.025 and 0.045. The curvature of a coil was defined as the ratio of the inside diameter of the tube to the diameter of the bending circle. To compare the condensation heat transfer coefficients of coiled spiral tubes, the previous results on coiled plain tubes and straight plain tubes were used. The results shows that the condensation heat transfer coefficients of coiled spiral tubes largely increase, as increasing Re and quality, compared to those of coiled plain tubes and straight plain tubes. As increasing degree of subcooling, however, the condensation heat transfer coefficients on coiled spiral tubes decrease. It is found that the heat transfer enhancement is more better than coiled plain tubes and straight plain tubes, as increasing curvature ratio.

• 태양에너지
• /
• 제19권2호
• /
• pp.1-8
• /
• 1999

The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

• Journal of Yeungnam Medical Science
• /
• 제14권1호
• /
• pp.237-244
• /
• 1997

A 14-year old boy was admitted with stuporous mentality. CT scan, MRI and cerebral angiogram revealed SAH and a giant aneurysm of right middle cerebral artery($4{\times}5{\times}5.3cm$). To minimize surgical risk, endovascular treatment was done with MDS(mechanical detachable system)-spiral coil. Follow up MRI showed intraluminal thrombus formation of the aneurysm.

• 전력전자학회논문지
• /
• 제24권2호
• /
• pp.78-83
• /
• 2019

In this study, we analyze the structure of the transceiver coil in the inductive power transfer (IPT) system. In the IPT system, the transceiver coil design needs to have the highest magnetic coupling possible because of the relatively low magnetic coupling due to the large gap of distance without the core. The transmitting coil may be formed as a multi-layer type according to the distance between the transmitting and receiving coils if the receiving coil is configured as a multi-layer type on the inner structure of the receiving apparatus, thereby improving the magnetic coupling and system efficiency. We compare and analyze the coil magnetic coupling, and system efficiency according to the layer structure of the transmitting and receiving coils and verify the analysis by JMAG simulation. Experimental results show that the layer structure of the transceiver should be considered according to the inner space of the receiving device and the spacing distance.

• 드라이브 ㆍ 컨트롤
• /
• 제12권4호
• /
• pp.1-7
• /
• 2015

In this study, a spiral valve which is used with a cryogenic linear expander and composed of plural plate coil shapes was examined. Generally, a spiral valve is well known for having excellent efficiency and low noise characteristics. In order to determine the movement characteristics and to investigate the limit of valve displacement, the stress variations according to the changes of operating pressure, displacement and workable temperature are discussed. From this examination, it is considered that the results of this study will significantly facilitate the design and development of a spiral valve for the cryogenic linear expander.