• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.177-180
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• 2010

Two-stage light gas gun, sorted with Ballistic Range System, is used to research spray characteristics of supersonic liquid jets. When high pressure tube was pressurized to the 135 bar, diaphragm films which composed with OHP film are ruptured. Expansion gases accelerate a projectile approximately 250 m/s at the exit of pump tube. And accelerated projectile collides with liquid storage part and liquid jets were injected into supersonic conditions. Supersonic liquid jets show the multiple jets and generate shockwave at the forward region of jets. Supersonic liquid jets of speed and shockwave angle have different value at each case. Supersonic liquid jets with minimum velocities are injected with M=1.53 at the geometry condition of L/d=23.8.

• Korean Journal of Food Science and Technology
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• v.54 no.3
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• pp.257-263
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• 2022

Various dietary pigments are added to processed foods to improve their sensory and commercial properties. In this study, autoclave sterilization (121℃ for 15 min at 15 psi) was performed on 34 food pigments, and changes in their color stability and antioxidant activity were analyzed. The autoclaving process drastically reduced the peak color intensities of water-soluble paprika and beet red (BR) by ~90%. Turmeric oleoresin (TO), water-soluble β-carotene, and grape skin color were also unstable and showed a remaining color intensity of 45-60%. The colors of all the synthetic pigments tested were stable under this process. The scavenging activities of BR and paprika against ABTS, DPPH, and AAPH radicals decreased significantly, whereas those of TO were enhanced after the autoclaving treatment. The results suggest that the chemical and bioactive properties of certain dietary pigments are affected by the autoclaving process, and this phenomenon should be considered during food processing.

• Fire Science and Engineering
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• v.28 no.6
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• pp.1-7
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• 2014

Vestibule pressurization system should produce uniform air egress velocity to prevent the intrusion of smoke into escape route when fire accidents occur inside a building and fire doors are open for evacuation of people. Air supplying units in the vestibule need to be arranged by taking account of the location of doors and the volume of the vestibule. In this study, computational fluid dynamics (CFD) simulations were conducted for the vestibule where two doors are installed varying the location of a damper and louver angle. From simulations, we found that when the damper in the vestibule is located at the center of the wall opposite to two fire doors, the uniform air egress velocity can be obtained.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.26 no.5
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• pp.363-374
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• 1997

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.158-163
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• 1997

신형 경수로심의 네가지 개념설계안을 제시하였다. 각 설계안은 압력관내에 농축우라늄 핵연료 다발을 CANDU처럼 장전하고 냉각수를 경수로 바꾼 안으로써 본 연구는 각 설계안의 장단점과 타당성을 검토하였다. 가연성 독봉인 IFBA를 사용하여 기존 CANDU 제어 시스템만으로 노심 잉여반응도의 제어가 가능함을 확인하였다.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.177-177
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• 2004

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.637-639
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• 2012

본 논문에서는 대형 공조기기에서 냉매의 회수시간을 단축하기 위해 진공과 가압방식을 겸용하면서 작업 시 이동이 손쉽게 소형으로 회수 및 충전이 가능할 수 있는 냉매 회수 및 충전 전용기 개발을 하고자 한다. 냉매회수시스템의 작업과정은 냉매회수 장치와 냉동기의 증발기 하부에 충진용 밸브를 호스로 연결하고 진공펌프를 운전하여 저장 탱크 내에 부착된 압력계가 진공상태가 될 때까지 액냉매를 회수 한 후, 자체적으로 증발, 흡입, 액화시켜 탱크내의 온도와 압력을 낮추어 액화된 냉매를 저장탱크로 회수하는 장치로 구성되어 있다.

• Nuclear Engineering and Technology
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• v.20 no.1
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• pp.1-8
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• 1988

During power plant operation, the flow rate from the CVCS makeup system is estimated using the continuity equation and mass balance equation, when the primary loop boron concentration change is required due to the power transient. For this purpose, primary loop, pressurizer and VCT(volume control tank)(in CVCS) are modeled by three control volumes which contain each mass and boron concentration. Connecting pipes between primary loop, pressurizer and CVCS are also modeled by time delay. Calculation for 14-2-6-2 (power 100-50-100) load follow case (at EOL, for KNU 7) is made using these models.

• Fire Science and Engineering
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• v.23 no.4
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• pp.145-153
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• 2009

We are generally applicate smoke control only vestibule about special escape staircase, it is one of some smoke control model of NFSC 501A. But there are some point at issue in this system. The smoke control system on supervision field of writer is smoke control only vestibule same as the other resemble field. Writer studied in the concrete to find a solution at this issue, and derived a conclusion the most reasonable system on the field is "same time smoke control for staircase and vestibule" by the engineering analysis considering stack effect.

• Fire Science and Engineering
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• v.21 no.4
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• pp.12-17
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• 2007

This paper investigated pressure differentials in the elevator lobby depending on reference pressures of the pressurizing damper using FDS fire modeling. The results showed the temperatures and pressures in the contained fire room with small leak gaps can increase significantly. Setting reference pressure of the pressurizing dampers to 0 Pa can cause reduction of real pressure differentials and air velocity to resist smoke flow. This would cause smoke movement from fire room to elevator lobby which should be safe area for evacuation.