• 전기의세계
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• v.9
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• pp.11-17
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• 1962

본 연구는 냉음극방전등의 기동특성에 방사성동위원소의 이온화작용을 이용하여 기동특성의 개량을 시도하려는 것이다. 냉음극이나 열음극방전등을 막론하고 일반으로 사용되는 것은 상용전압인 저전압에서는 직접 점등이 불능하기 때문에 순시 또는 한시적인 승압장치가 필요하나. 예컨데 네온 관과 같는 냉음극방전등에서는 한시적인 승압 및 방전전류의 제한때문에 누설변압기를 사용하고 또 형광방전관 및 저압수은방전관과 같은 열음극방전관은 저전압기동을 위한 음극의 가열과 순시적인 승압장치로 점등관 및 쵸크코일등을 사용하고 있다.이와같이 방전등에서는 고전압기동으로 말미암은 승압장치 때문에 경제적 부담과 전력의 손실을 초래하고 있다. 그러기 때문에 저전압기동을 해결하는 것과 방전등의 방전개시전압의 부정으로 인한 방전개시전압의 시간적인 변동을 해결하는 것이 중요한 방전등 기동특성의 개량이다. 그리고 일반방전등에서는 그다지 문제되여 있지 않지만 방전이 늦임도 기동의 한 요소로 되어있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.53-58
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• 2001

The main noise sources in SMPS are divided into three parts: the switching devices, the rectifiers in secondary part, the output transformer and choke coil. In this paper we performed the noise analysis with respect to bobbin type and winding method, and designed an optimized transformer focusing on the transformer. For the comparison. we measured four parameters for each cases, including EMI conducted emission noise. signal from the switching devices, output ripple/noise voltage and leakage current. As the result, the transformer using a vertically-typed bobbin and a parallel, sandwich winding method showed the best performance. We confirmed that the SMPS developed in this research is satisfied with the IEC 601-1 international standard for the medical instrumentation. by testing its electrical characteristics and safety.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.05a
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• pp.59-63
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• 2003

This paper describes the conceptual design method of subscale direct-connect test facility for liquid fuel ramjet combustion study and preliminary analysis of test results. The measured pressure signal represents the successful operation of the test facility. The pressure oscillation in combustion chamber shows the dominant frequency of 190Hz, relatively very low frequency to 1L acoustic mode (1200Hz) based on the length of combustor. It is suspected that there were several driving sources, which are vortex street at backward step of combustor, inlet resonance induced by the long length of unchecked inlet, and/or combustor configuration with optical window.

• Journal of the Korean Magnetics Society
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• v.15 no.1
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• pp.30-36
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• 2005

Recently, It has been reported that the spin sprayed ferite film shows better magnetic properties at high frequeny that the ferrite by co-firing over $800^{\circ}C$ . Besides, there is no limitation to select the substrate materials because it can be processed with relatively low temperature below $100^{\circ}C$. Therefore, we fabricated film inductor as a passive device for DC-DC converter by a use of spin sprayed embedded form was completed by via hole process of pad opening. Saturation magnetization of 0.61 T and real part of permeability of 110 were obtained in Ni-Zn ferrite. In addition, inductance of 1.52 ${\mu}H$, quality factor of 24.3 at 5 MHz were measured with spiral 16 turn inductor. The rated current of inductor was 863 mA.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.352-359
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• 2003

In this paper, we designed the bluetooth receiver using the microstrip bandpass filter and the high gain low noise amplifier with the 0.2$\mu\textrm{m}$ CMOS technology. A cascode inverter is adopted to implement the low noise amplifier and is one stage amplifier with a voltage reference and without the choke inductor. The designed 2.4GHz LNA was achieved a power gain of 18dB, a noise figure of 2.8dB, and the power consumption of 255mW at 2.5V power supply. Also, the microstrip receiver bandpass filter was designed that the center frequency was 2.45GHz, the bandwidth was 4% and the insert attenuation was -1.9dB. When the microstrip bandpass filter and LNA was simulated together the power gain was 16.3dB.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.90-103
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• 2018

This paper presents the development of two ANN models which can predict an optimum production rate by controlling choke size in oil well, and gas injection rate in gas-lift well. The input data was solution gas-oil ratio, water cut, reservoir pressure, and choke size or gas injection rate. The output data was wellhead pressure and production rate. Firstly, a range of each parameters was decided by conducting sensitive analysis of input data for onshore oil well. In addition, 1,715 sets training data for choke size decision model and 1,225 sets for gas injection rate decision model were generated by nodal analysis. From the results of comparing between the nodal analysis and the ANN on the same reservoir system showed that the correlation factors were very high(>0.99). Mean absolute error of wellhead pressure and oil production rate was 0.55%, 1.05% with the choke size model, respectively. And the gas injection rate model showed the errors of 1.23%, 2.67%. It was found that the developed models had been highly accurate.