• Proceedings of the KSME Conference
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• 2003.11a
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• pp.373-378
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• 2003

It is important that overheat protection of super heated tube in boiler operation and maintenance. The overheat of super heat tube can make damage and rupture of tube material, which causes accidental shutdown of boiler. The super heated tube overheat is almost due to the lack of uniformity of gas temperature distribution. There are two ways to protect overheat of super heated tube. The one is to control hot gas operation pattern which is temperature or flow distribution. the other is to control super heated steam flow distribution. The former is difficult than the later, because of control device design. In this paper steam flow control method which uses orifices is proposed to protect overheat of super heat tube.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.222-227
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• 2003

Recent advances in room-temperature, visible and near-IR diode laser sources for telecommunication, optical data storage applications are enabling combustion diagnostics system based on diode laser absorption spectroscopy. In contrast to some traditional sampling-based gas-sensing instruments, tunable diode laser absorption spectroscopy system is advantageous because of their non-invasive nature, high sensitivity, fast response time and real-time measurement capability. So, combined with fiber-optics and high sensitive detection strategies, compact and portable sensor system arc now appearing for a variety of applications. The objective of this research is to take advantage of distributed feed-back diode laser and measure the $CO_{2}$ concentration (by using direct absorption and wavelength modulation spectroscopy methods). In addition to survey spectra of $CO_{2}$ bands and spectroscopic parameters between 1565 and 1579 run were computed at temperatures between 296 and 1200 K (by using HITRAN 2000 database). It experimentally found out that the features of direct absorption and wavelength modulation spectroscopy methods.

• Journal of ILASS-Korea
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• v.21 no.1
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• pp.37-46
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• 2016

For the SI engines, at only full load, the pumping loss has a negligible effect, while at part load conditions, the pumping loss increases. To avoid the pumping loss, the spark-ignited engines are designed to inject gasoline directly into the combustion chamber. In the spark-ignited direct-injection engines, ignition probability is important for successful combustion and the flame propagation characteristics are also different from that of pre-mixed combustion. In this paper, a visualization experiment system is designed to study the ignition probability and combustion flame characteristics of spark-ignited direct-injection CNG fuel. The visualization system is composed of a combustion chamber, fuel supply system, air supply system, electronic control system and data acquisition system. It is found that ambient pressure, ambient temperature and ambient air flow velocity are important parameters which affect the ignition probability of CNG-air mixture and flame propagation characteristics and the injected CNG fuel can be ignited directly by a spark-plug under proper ambient conditions. For all cases of successful ignition, the flame propagation images were digitally recorded with an intensified CCD camera and the flame propagation characteristics were analyzed.

• Journal of ILASS-Korea
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• v.14 no.3
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• pp.103-108
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• 2009

This research investigated spray characteristics using LPG fuel under compression ignition to contribute to develop a high efficiency LPG fuel is an environmentally-friendly fuel since it emits lower $CO_2$ compare to other conventional fuels. In order to observe spray process, a high speed digital camera and high pressure common-rail injector were applied. Using the spray behaviors of LPG and diesel fuel from the experiment, this research analyzed the mixing process of air-fuel mixture numerically with FLUENT 6.3 when LPG and diesel fuel injected directly into the cylinder while compression stroke occurs. Spray characteristics of LPG fuel was investigated by using numerical method, in which KH-RT model was adapted for phase change. As a result of numerical analysis, this work found out that LPG spray has a wider mixing formation and uniform diffusion of air-fuel mixture compare to diesel.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.3 s.14
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• pp.83-87
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• 2004

In underground culvert are established main and basic facilities for electric power, communication, gas and heating pipe etc. In the future the use of underground culvert will be enlarged and the peril of fire will be increased. Thus it is necessary to make a general plan to prevent fire. The skills to prevent fire in underground culvert will be accumulated by the spray distribution of the nozzle and domestic skills in fire fighting will be upgraded. It will also contribute to the construction of common small fire fighting system suitable to the domestic surrounding and the growth of domestic skills for fire fighting and disaster prevention.

• Analytical Science and Technology
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• v.23 no.3
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• pp.269-277
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• 2010

Air samples were collected and analyzed to investigate regional level of PAHs and its emission sources. The average concentrations of PAHs in the suburban (Gwanak) and in the urban (Seodaemun) area were $16.52\;ng/m^3$ and $59.1\;ng/m^3$, respectively. Phenanthrene, fluoranthene, pyrene, and fluorene were predominant PAHs species, as their sum contributed to 55.6% and 60.8% of the total PAHs, respectively. The possible major source of PAHs was suspect to be the combustion of diesel fueled vehicles in both areas, particularly for Seodaemun.

• Fire Science and Engineering
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• v.31 no.6
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• pp.112-117
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• 2017

This research discusses the correlation about fire mechanism based on real fire cases. Electric power condenser failure mechanism is classified into 7 steps and fire mechanism is classified into 12 steps. In the 5th step, the procedure of operating a protection channel of a protection relay was identical in the case of the failure and fire. As the fire occurrence mechanism was applied from the 6th step, internal pressure was increased because of gas generation produced by internal combustion phenomenon and arc. This caused explosion in 10st step of fire occurrence mechanism. In 11th step, the flame such as arc gushed out with insulating oil which caused fire and leaded to second accident. This kind of step correlation could play an important part to examine fire.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.436-440
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• 2011

본 연구는 산불발생에 따른 온실가스 배출량 추정을 위한 기초 data 제공에 주안점을 두고 산림연료를 대상으로 연소실험을 수행하였다. 연료의 대상은 참나무(굴참, 떡갈, 신갈, 갈참, 졸참, 상수리)를 대상으로 부위별(생엽, 가지, 수피) 채취하여 사용하였으며, 콘칼로리미터를 이용하여 $CO_2$ 배출량을 분석하였다. 중량 50g의 연료 기준에 대한 $CO_2$ 배출량은 생엽 42.38~95.41g, 가지 82.92~113.10g, 수피 72.64~100.70g 정도 범위에서 $CO_2$를 배출하는 것으로 나타났다. 부위별 평균배출량을 살펴보면, 생엽 72.10g, 가지 101.88, 수피 86.46g 정도의 값을 보여 가지부위가 가장 많은 $CO_2$를 배출하는 것을 알 수 있었으며, 또한, $CO_2$를 상대적으로 많이 배출한 수종으로는 상수리나무인 것으로 나타났다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.248-252
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• 2011

화재가 지속되기 위해서는 화재 3요소 또는 4요소가 충족되어야 하지만 역으로 한 개 이상의 화재 요소를 제어하거나 통제할 경우 화재를 진압할 수 있다. 원자력발전소에서는 화재방호계획에 의해 방화지역마다 화재 요인인 점화원, 가연성물질, 산소 등 지연성가스를 분석하고 연속적인 연소반응을 억제할 수 있도록 화재위험 요인을 관리하고 있다. 최근에는 정량화된 화재위험 분석도구인 화재모델을 활용한 성능기반 화재방호 기술이 원자력발전소의 화재리스크 관리를 위해 도입되고 있다. 성능기반 화재위험 분석 방법은 일반 산업계에서도 사용되고 있으나 원자력발전소의 경우 화재로 유발될 수 있는 원자로 손상 가능성을 수치화하고 통제하기 위하여 위험도정보 활용기술과 성능기반 기술을 통합하여 사용하고 있다. 본 논문에서는 원자력발전소의 화재요인 관리 방법을 위험도정보 활용기술과 성능기반 화재방호 기술에 의거하여 분석하는 방법을 제시하였다. 이 분석의 목적은 원자력발전소의 화재위험 관리 방법을 산업계의 화재방호 전문가들이 공유하고 산업계의 특화된 방법과 원자력발전소의 전문화된 분석기술을 실용화하여 화재리스크를 효과적으로 관리할 수 있는 방법을 마련하기 위한 것이다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.93.2-93.2
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• 2012

연료전지는 전기화학반응을 이용한 발전 장치로서 기존 장치에 비하여 발전 효율이 높아 화석연료를 사용하면서 현재 당면 과제인 $CO_2$ 배출량 절감이 가능하고, 환경 보전성이 우수하여 미래의 전원으로 많은 연구개발이 진행되고 있다. 특히 제3세대 연료전지라 불리는 고체산화물 연료전지(Solid Oxide Fuel Cell이하 SOFC)는 고가의 외부 개질 장치 없이도 연료가 갖는 화학에너지를 연소과정 없이, 공기와 $H_2$, CO, $CH_4$와 같은 환원성 가스를 공급받아 $600{\sim}1000^{\circ}C$에서 전기화학적 반응을 통하여 직접 전기를 얻는 방식이며, 낮은 소음과 진동으로 인하여 온 사이트(On-site) 발전이 가능한 장점이 있는 연료전지이다. Decalcomanie는 전사용지에 Screen printing하여 건조 후 coating하는 방법으로 기존의 여러 coating 방법보다 다전지셀 제작이나 Buffer layer의 적용이 용이하고, 소재의 크기나 두께조절이 간편하며, 구성층의 표면조도나 굴곡에 대응이 용이한 방법이다. 새로운 Decalcomanie를 사용하여 평관형 다전지식 SOFC Cell 제작 및 각 Buffer layer에 적용, Screen printing법과 동일한 Cell 제조 후 MPD와 Impedance 분석을 통하여 Support 위에 전사지를 이용, 적층한 Cell의 전기화학적 특성에 관하여 분석하였다.