• Journal of Electrical Engineering and Technology
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• v.11 no.3
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• pp.775-780
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• 2016

This induced voltage measurement test and electromagnetic field simulation are related to the possibility of control signal malfunction by power line. Through an experiment, this research analyzed whether the voltage causing control malfunction according to the on/off status of power permitted to power line was induced to control signal line. Also, the research calculated the voltage induced to control signal line and examined the phenomenon by conducting an electro-magnetic field-specific simulation through the finite element method for the cable model used in the experiment.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.786-787
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• 2008

본 논문에서는 1층 주거지역에 미치는 지하 분전반 모선으로부터 발생하는 극저주파 자기장을 억제하기 위한 연구의 일환으로 지하 분전반을 연구모델로 선정한 후 3차원 전자장 유한요소 해석을 이용하여 누설 자속을 분석하였다. 1층 침실에 미치는 자기장을 억제하기 위해 알루미늄 재질의 차폐판을 도입하여 차폐효과를 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.424-424
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• 2000

The implementation of a insect-based flying microrobot has been previously proposed as using magnetic force. The flying principle of a butterfly is different from that of a airplane, which obtain lifting force above the wings by a air stream with low pressure. Butterflies obtain lifting force below the wings by flapping. They can fly when drag during the down stroke is greater that during the up stroke. The structure of flying microrobot must satisfy these condition. And that must be manufacture lightly and keep balance for rising to the air sufficiently. Moreover the efficiency of an electromagnet is high and the flux density is sustained uniformly and widely Nevertheless these condition is satisfied, the implementation of a flying microrobot is very difficult as the flying microrobot has to fly without guides or sensor. We propose differently a new model il] comparison with that other paper has suggested. This imitates the form of the Korean shield-shaped kite.

• Nuclear Engineering and Technology
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• v.55 no.7
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• pp.2407-2418
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• 2023

Internal replaceable electronic module substitutions can impact EMC (ElectroMagnetic Compatibility) qualification testing and results if EMC testing is conducted at the cabinet level. The impact of component substitutions on EMC qualification results therefore should be evaluated. If a qualitative evaluation is not adequate to ensure that the modified product will not impact the cabinet level EMC qualification results, a new qualification testing should be conducted. Component level retesting should be conducted under electromagnetically equivalent conditions with the cabinet level test. This paper analyzes the propagation of conducted susceptibility test waveforms in a representative cabinet and evaluates the impact of component substitutions on cabinet level EMC qualification results according to the location of the replacement items. A guideline for a qualitative evaluation of the impact of component substitutions is described based on the propagation of the conducted susceptibility test waveforms. A module level test method is also described based on an analysis of the shielding effectiveness of the cabinet.

• Journal of electromagnetic engineering and science
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• v.11 no.3
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• pp.166-173
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• 2011

In this paper, we implemented and analyzed a wireless power transfer (WPT) system with a CSPR topology. CSPR refers to constant current source, series resonance circuit topology of a transmitting coil, parallel resonance circuit topology of a receiving coil, and pure resistive loading. The transmitting coil is coupled by a magnetic field to the receiving coil without wire. Although the electromotive force (emf) is small (about 4.5V), the voltage on load resistor is 148V, because a parallel resonance scheme was adopted for the receiving coil. The implemented WPT system is designed to be able to transfer up to 1 kW power and can operate a LED TV. Before the implementation, the EMF reduction mechanism based on the use of ferrite and a metal shield box was confirmed by an EM simulation and we found that the EMF can be suppressed dramatically by using this shield. The operating frequency of the implemented WPT system is 30.7kHz and the air gap between two coils is 150mm. The power transferred to the load resistor is 147W and the real power transfer efficiency is 66.4 %.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.684-688
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• 2016

The magnetic resonance method requires high quality factor(Q-factor) of resonators. Superconductor coils were used in this study to increase the Q-factor of wireless power transfer(WPT) systems in the magnetic resonance method. The results showed better transfer efficiency compared to copper coils. However, as superconducting coils should be cooled below critical temperatures, they require cooling containers. In this viewpoint, shielding materials for the cooling containers were applied for the analysis of the WPT characteristics. The shielding materials were applied at both ends of the transmitter and receiver coils. Iron, aluminum, and plastic were used for shielding. The electric field distribution and S-parameters (S11, S21) of superconducting coils were compared and analyzed according to the shield materials. As a result, plastic shielding showed better transfer efficiency, while iron and aluminum had less efficiency. Also, the maximum magnetic field distribution of the coils according to the shielding materials was analyzed. It was found that plastic shielding had 5 times bigger power transfer rate than iron or aluminum. It is suggested that the reliability of superconducting WPT systems can be secured if plastic is used for the cooling containers of superconducting resonance coils.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.521-522
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• 2008

21세기를 접하면서 산업전자 분야의 비약적인 발전과 함께 과학문명은 눈부시게 발전해 나아가고 있다. 이것의 원천은 바로 전기(Electric)이다. 우리는 풍요로운 삶 자체를 전기 공급에서 누리고 있으며 또 비극적인 사태를 맞이할 때도 있다. 즉, 전기기기를 이용하면 원하건 원치 않건 전자기파가 발생이 된다 이것이 자연현상이며 전자기파는 IT, BT, CT를 비롯하여 산업 전체에 많은 영향을 미치고 있다. 일반적으로 우리가 말하는 전자기파 장해의 기본 요소는 노이즈원(잡음원), 경로매체, 피해장치 등으로 구성되는 데 잡음원(Noise Source)은 각종 시스템에서 구성되고 있는 전자기 에너지의 발생원으로 볼 수 있으며 이 발생원에서 경로매체(금속:전도성, 대기중:전파성 등)를 통하여 피해장치(전기전자통신기기류)에 방해를 주고 있는 상태를 전자기파 장해라고 설명할 수 있다. 전자기파 잡음원에서 경로를 거쳐 전자기파에 대하여 피해장치가 안정된 상태로 동작하도록 규정하는 용어 즉, 전자파 양립성 또는 적합성 (EMC : Electro Magnetic Compatibility))이란 용어를 가지고 전기 전자 통신기기에서 발생되는 불필요한 전자파와 전자파 내성시험을 만족하도록 의무화하고 있다. EMC 는 EMI (불요 전자파 또는 전자파 간섭 : Electro Magnetic Interference) + EMS (전자파 내성 : Electro Magnetic Susceptibility) 2가지 시험을 함께 전자파 적합성 (EMC) 시험으로 표현되고 있다. 전자파 적합성 시험의 목적으로 EMl는 전도성 또는 전파성에 대한 주파수 대역(잡음)을 보호하기 위한 것이 목적이고 EMS는 프로세서가 내장된 기기류의 오동작을 방지하기 위하여 감응평가를 하는 것이다. 즉, 감응(Susceptibility)이란 어떤 장비나 시스템이 전자기파 장해에 쉽게 영향을 받는 것을 뜻하는 데 전자파 장해를 견디면서 본래의 기능을 충분하게 발휘하며 동작할 수 있는 능력을 말한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.57-63
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• 2019

S-parameters were used to analyze the effect of the circuit according to the height of the EMI shield layers. Among the S-parameters, S11, S21, S22, and S31 were used as factors for determining the effect on the circuit function. Simulations were performed using shields made of Graphite and Ferrite, and the frequencies were run from 100 MHz to 1 GHz. As the height of the shield was increased, the value of S21 was getting closer to 0 dB. In addition, the SE value was confirmed to improve the shielding performance according to the thickness of the insulating layer only in a specific frequency band. Based on 800um with thickest silicon dioxide thickness, the FG structure averaged -1 dB in narrow frequency bands between 100 MHz and 300 MHz, showing better efficiency than GF with an average of -2 dB. Although GF structures do not show high efficiency, they exhibit average performance of -3 dB in frequency bands between 100 MHz and 1 GHz rather than FG structures that sway over a wide range. In other words, FG and GF structures have trade-off structures. Therefore, it should be noted that the appropriate structure is selected for use.

• Journal of the Korean Society of Radiology
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• v.13 no.1
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• pp.87-93
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• 2019

Recently, the number of passengers using airplanes is rapidly increasing due to the increase of overseas travelers. Therefore, the probability of exposure to natural radiation due to altitude is increasing due to the increase in flight time. Cosmic-ray penetrates the Earth's magnetic field belt Van Allen, which is located at an altitude of 400 km to 1200 km. Most cosmic rays are blocked at Van Allen belt. However, cosmic-ray could be not completely blocked, and a small amount of cosmic-ray affects the earth. In general, if the altitude was increased by 100m, the natural exposure dose increased by 0.03 mSv on the Earth. In this study, I tried to minimize the exposure to natural radiation in airplanes when boarding airplanes. Especially, I was aimed to minimize radiation exposure by protecting the highly sensitive thyroid gland among human organs. According to the results of the study, the designed shielding handkerchief was able to shield cosmic natural radiation dose by more than 70%. In conclusion, the application of the shielding handkerchief made in this study can be effectively shield natural radiation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.5
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• pp.216-220
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• 2010

Ni-Fe alloys have various applications such as thin film inductor, thin film transformer, magnetic head's shield case, etc. Magnetic properties of Ni-Fe thin films depend on the process parameters such as thickness, contents, deposition rate, substrates, etc. In this study, NiFe films with a thickness of about 150nm were deposited on Si(100) wafer and $SiO_2$/Si(100) substrate at room temperature by a DC magnetron co-sputtering using Fe and Ni targets. Their phase formation and magnetic properties as a function of annealing temperature were investigated with XRD, FE-SEM and VSM. The assputtered films have BCC structure. With increasing annealing temperature, NiFe thin film for $SiO_2$/Si(100) substrate transformed completely from BCC to FCC phase above $500^{\circ}C$, but some BCC phase remained above $500^{\circ}C$ on Si(100) wafer. For samples annealed at $450^{\circ}C$, squareness ratio of NiFe thin film shows peak value and its saturation magnetization is around 0.0118 emu, which means that the optimum annealing temperature of NiFe thin film seems to be $450^{\circ}C$. The saturation magnetization of films decreased rapidly above the annealing temperature of $500^{\circ}C$ due to phase transformation from BCC to FCC phase.