• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.872-878
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• 2018

Steam tables including superheated, saturated and compressed region were simultaneously modeled using the neural networks. Pressure and temperature were used as two inputs for superheated and compressed region. On the other hand Pressure and dryness fraction were two inputs for saturated region. The outputs were specific volume, specific enthalpy and specific entropy. The neural network model were compared with the linear interpolation model in terms of the percentage relative errors. The criterion of judgement was selected with the percentage relative error of 1%. In conclusion the neural networks showed better results than the interpolation method for all data of superheated and compressed region and specific volume of saturated region, but similar for specific enthalpy and entropy of saturated region.

• Journal of Radiation Protection and Research
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• v.13 no.1
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• pp.1-7
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• 1988

A bubble-damage polymer detector, which operation principles are based on vaporization of superheated liquid drops by interaction with radiations, is developed for neutron dosimetry. The detectors are fabricated by dispersing the superheated liquid drops of Freon12 into transparent and elastic polymer made of acylamide and glycerine. The bubbles formed by neutron irradiation are immediately visible. The neutron sensitivity of the detectors is 4-7 bubbles/10$\mu$ Sv for Am-Be neutrons.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.249-250
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• 2009

• 보일러설비
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• s.81
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• pp.99-100
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• 2000

심야전력 보급이 활성화됨에 따라 예년에 비해 보급업체 및 판매점이 급격히 증가하고 있어, 판매업체의 과열경쟁이나 무리한 마아케팅 과정에서 관리상의 허점을 이용하여 다음과 같은 부적정 공급 사례가 발생하고 있습니다. 향후 아래와 같은 사례를 엄격히 금지하오니 참조하시기 바랍니다.

• 주택과사람들
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• s.201
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• pp.26-27
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• 2007

오는 9월부터 투기과열지구의 민간 아파트 원가가 공개될 예정이다. 일반 택지 개발 아파트뿐만 아니라 재개발, 재건축, 주상복합도 분양가 규제와 함께 원가 공개 적용 대상에 포함됐다. 분양가 원가 공개의 장단점을 분석해본다.

• KAPE Magazine
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• s.229
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• pp.30-32
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• 2015

우리나라는 식육 역사가 짧다. 여기에 부정확한 자료가 사실인 냥 유통되고, 과열 먹방이 더해지고 있어 더 많은 육식 괴담이 성행할 것이다. 영화와 TV프로그램 가이드가 있듯, 원초적 미각 단계에서 '식문화(食文化)'단계로 업그레이드 시키는 음식문화 가이드의 양성이 긴요하다.

• Electric Engineers Magazine
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• v.230 no.10
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• pp.22-29
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• 2001

변압기에서의 고조파의 영향은 두 부분이 있다. 고조파 전류는 동손과 Stay flux 손실을 증가시키는 원인이 되고 고조파 전압은 철손을 증가시킨다. 포괄적으로 순수한 정현파 동작에 비해서 변압기를 과열시킨다.

• Journal of the Korean Institute of Gas
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• v.14 no.1
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• pp.1-7
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• 2010

In this paper, cycle performance analysis of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree, compressor efficiency, and condensing and evaporating temperature in the ammonia(R717) high temperature cycle and the carbon dioxide low temperature cycle. The main results were summarized as follows : The COP of two-stage cascade refrigeration system increases with the increasing subcooling degree, but decreases with the increasing superheating degree. The COP of two-stage cascade refrigeration system decreases with the increasing condensing temperature, but increases with the increasing evaporating temperature. And the COP of two-stage cascade refrigeration system increases with increasing the compressor efficiency. Therefore, superheating and subcoolng degree, compressor efficiency, and evaporating and condensing temperature of $NH_3-CO_2$(R717-R744) two-stage cascade refrigeration system have an effect on the COP of this system.

• Journal of Advanced Marine Engineering and Technology
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• v.37 no.6
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• pp.575-581
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• 2013

In this paper, the influences of several factors, such as subcooling, superheating degree, internal heat exchanger efficiency, and etc. to the optimal amount of refrigerant charge are investigated for the case of R744-R404A cascade refrigeration system. Refrigerants used in the cascade refrigeration system are R404A in high temperature cycle and R744 in the low temperature cycle. The main results are summarized as follows : The mass flow rate ratio decreases with increasing subcooling, superheating degree and internal heat exchanger efficiency in the high temperature cycle, and evaporating temperature and compression efficiency in the low temperature cycle. And the mass flow rate ratio decreases with decreasing temperature difference of cascade heat exchanger and evaporating, condensing temperature in the high temperature cycle, and subcooling, superheating degree and internal heat exchanger efficiency in the low temperature cycle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2565-2571
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• 2009

In this paper, cycle performance analysis of cascade refrigeration system using $NH_3-CO_2$(R717-R744) is presented to offer the basic design data for the operating parameters of the system. The operating parameters considered in this study include subcooling and superheating degree and condensing and evaporating temperature in the ammonia(R717) high temperature cycle and the carbon dioxide low temperature cycle. The COP of cascade refrigeration system increases with the increasing superheating degree, but decreases with the increasing subcooling degree. The COP of cascade refrigeration system increases with the increasing condensing temperature, but decreases with the increasing evaporating temperature. Therefore, superheating and subcoolng degree, evaporating and condensing temperature of cascade refrigeration system using $NH_3-CO_2$ have an effect on the COP of this system. A multilinear regression analysis was employed in terms of subcooling, superheating, evaporating, condensing, and cascade heat exchanger temperature difference in order to develop mathematical expressions for maximum COP and an optimum evaporating temperature.