• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.1
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• pp.67-75
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• 2016

In this paper, a pressure-time history curve of blast load and Conwep model are presented, and a simplified blast load formula is suggested. Generally, a blast load are applied as a pressure-time history curve, and it is calculated by blast load formula such as Conwep model. The Conwep model which is used in most of the blast analysis is quiet difficult to calculate because of its complex process. Therefore, a simplified formula is proposed to calculate blast load by simple rational expressions and to make a simplified pressure-time history curve. In this process, a curve fitting method was used to find the simple rational expressions. The calculation results of the simplified formula have an error of less than 1% in comparison with the Conwep model. And, blast analyses using finite elements method are accomplished with the Conwep model and simplified formula for verification.

• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.8-14
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• 2012

Hydrogen is considered to be the most important future energy carrier in many applications reducing significantly greenhouse gas emissions, but the explosion safety issues associated with hydrogen applications need to be investigated and fully understood to be applicable as the carrier. The risk associated with a explosion depends on an understanding of the impacts of the explosion, particularly the pressure-time history during the explosion. This work provides the effects of explosion parameters, such as specific heat ratio of burned and unburned gas, equilibrium maximum explosion pressure, and burning velocity, on the pressure-time history with flame growth model. The pressure-time history is dominantly depending on the burning velocity and equilibrium maximum explosion pressure of hydrogen-air mixture. The pressure rise rate increase with the burning velocity and equilibrium maximum explosion pressure. The specific heat ratio of unburned gas has more effect on the final explosion pressure increase rate than initial explosion pressure increase rate. However, the specific heat ratio of burned gas has more influence on initial explosion pressure increase rate. The flame speeds are obtained by fitting the experimental data sets. The flame speeds for hydrogen in air based on our experimental data is very low, making a transition from deflagration to detonation in a confined space unlikely under these conditions.

• Explosives and Blasting
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• v.42 no.2
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• pp.12-28
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• 2024

Explosion involving rapid energy diffusion are causing enormous human and economic damage. Due to the advancement of the industry, various and widespread explosion accidents are occurring worldwise, and to prevent such explosion accidents, accurate cause analysis should be the basis. Research analysis related to worldwise explosion accidents was carried out in a limited range for some accidents. By conducting bibliometric analysis of keywords on all the papers published in international journals, this study attempted to derive the overall research trend by period and the latest fields in which future researchers may be interested. As a result of the study of keywords, the number of papers was generally small and the number of overall key words was small from 2005 to 2014, but numerical simulation and artificial intelligence have been used for the analysis of explosion accident cases since 2015, and various studies such as lithium-ion battery and mixed gas, which are the latest research fields, are currently being actively conducted.

• 건강소식
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• v.36 no.4
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• pp.32-33
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• 2012

트라우마(trauma)는 외상 후 스트레스 장애다. 극단적인 트라우마의 기억은 그 당시에 경험했던 생생한 감정이나 신체 감각의 잔재가 뇌 안의 신경 회로에 그대로 남아 있다가 일상생활에서 사소한 자극에 의해 그대로 폭발 되어 나온다.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.47.1-47.1
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• 2010

태양전파폭발위치관측기(KSRBL)는 단일 안테나 전파분광기로써 미 뉴저지공과대학과의 협력으로 2009년 8월에 한국천문연구원에 개발 설치되었다. 1 MHz 스펙트럼 분해능과 1초의 시간 분해능을 가지고 있고 관측할 수 있는 주파수 대역은 245, 410 MHz 와 0.5-18 GHz에 이르는 광대역이다. 또한 태양 전면 $0.03^{\circ}$ 각거리 안의 오차 범위 내에 태양 폭발 위치를 감지할 수 있다. 전파 관측은 LabVIEW와 IDL 프로그램에 의해 미리 짜여진 관측 스케줄에 따라 매일 자동으로 진행된다. KSRBL 설치 이후 현재까지의 데이터에 대한 관측 통계를 분석 하였다. 관측된 전파폭발의 수를 다른 사이트와 비교하고, 정상 관측 되는 날의 빈도, 기기 오류 발생 빈도, 데이터 안정도 및 손실률 등의 변화양상을 추적하였다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.131.2-131.2
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• 2012

태양전파폭발위치감지기(KSRBL)는 단일 안테나 전파분광기로써 미 뉴저지공과대학과의 협력으로 2009년 8월에 한국천문연구원에 개발 설치되었다. 1 MHz 스펙트럼 분해능과 1초의 시간 분해능을 가지고 있고 관측할 수 있는 주파수 대역은 245, 410 MHz 와 0.5-18 GHz에 이르는 광대역이다. 또한 태양 전면 태양 폭발 위치를 감지할 수 있다. 전파 관측은 LabVIEW와 IDL 프로그램에 의해 미리 짜여진 관측 스케줄에 따라 매일 자동으로 진행된다. 데이터 분석을 위해 필요한 플럭스, 안테나, 전파 이득에 대한 눈금조정 작업을 위한 소프트웨어를 개발하였다. 2009년 설치이후 지금까지 12개의 이벤트를 관측하였고 그 중 5개의 이벤트를 가지고 관측된 스펙트럼의 모듈레이션 패턴을 분석하여 태양면상에서 전파 폭발의 위치 값을 구했다. Solar Dynamics Observatory(SDO) AIA 이미지와 비교해 KSRBL의 위치감지 성능을 분석하였다.

• Journal of the Korea Concrete Institute
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• v.25 no.1
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• pp.107-114
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• 2013

In this study we experimentally evaluated an impact resistant performance of fiber reinforced concrete in the moment of explosion by high-velocity projectile with emulsion explosive. To assess the impact resistance, we conducted the impact test of high-velocity projectile which reaches an impact speed of 350 m/s and the experiment of contact exploding emulsion explosive. As a result, bending and tensile performance depending on type of PVA, PE fiber (polyvinyl alcohol fiber, polyethylene fiber) and steel fiber affects destruction of rear side in the form of spalling. Destroying the backside of the concrete compressive strength compared to suppress the bending and tensile performance is affected. In addition, the experiment shows that the destruction patterns of concrete specimen producted by high velocity impact and contact explosion are significantly similar. Therefore, it is possible to predict the destruction patterns of specimens in the situation of contact explosion by high-velocity projectile.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.65-75
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• 2022

Recently, the possibility of fire and explosion due to hydrogen leakage and the resulting risk are increasing since the operating pressure of the electrolysis increases. This study performed the hazardous area classification in accordance with KS C IEC 60079-10-1 and KGS GC101 in consideration of the general operating conditions of the electrolysis. In addition, in order to achieve a To Non-hazardous, an appropriate ventilation rate was estimated to maintain a concentration of less than 25 % of the lower explosive limit. As a result, it was reviewed that the electrolysis is classified as an hazardous area when only natural ventilation is applied, and a huge amount of ventilation is required to classify it as a non-hazardous area.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.33.1-33.1
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• 2010

태양전파폭발위치관측기(KSRBL)는 단일 안테나 전파분광기로써 미 뉴저지공과대학과의 협력으로 2009년 8월에 한국천문연구원에 개발 설치되었다. 1 MHz 스펙트럼 분해능과 1초의 시간 분해능을 가지고 있고 관측할 수 있는 주파수 대역은 245, 410 MHz 와 0.5-18 GHz에 이르는 광대역이다. 또한 태양 전면 $0.03^{\circ}$ 각거리 안의 오차 범위 내에 태양 폭발 위치를 감지할 수 있다. 전파 관측은 LabVIEW와 IDL 프로그램에 의해 미리 짜여진 관측 스케줄에 따라 매일 자동으로 진행된다. 하루에 생성되는 원시데이터는 90 GB 정도이며, 태양이 지고나면 원시데이터는 적분과정을 통해 용량이 6 GB 정도로 줄어들게 된다. 이렇게 처리된 파일은 바로 데이터 서버에 자동 전송된다. 또한 KSRBL 관측일지 홈페이지를 웹기반으로 개발하였으며 조만간 이를 데이터 전송과 연계하여 전파 폭발이 감지될 경우 원시데이터도 데이터 서버에 자동 전송되도록 할 예정이다. 2010년 1월에서 2월 8일 사이 5개의 전파 폭발이 관측되었고 태양활동이 점차 활발해짐에 따라 관측횟수는 더욱 늘어날 전망이다. 관측된 사례들에 대해 다른 전파 및 X선 관측과 비교분석하였다.

• Analytical Science and Technology
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• v.30 no.6
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• pp.405-410
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• 2017

High energetic materials (HEMs) have been used in fuels, civil engineering and architecture as well as military purposes such as explosives and propellants. The essential process for the development of new energetic compounds is to accurately calculate its detonation performances. The most typical equation for calculating the explosive performance is the Kamlet-Jacobs (K-J) equation. In the K-J equation, the parameter such as the number of moles of gaseous products at the explosion, the average molar mass of gas products, and the explosion heat greatly affect the explosion performance. These depend on the product composition for the detonation reaction. In this study, detonation products of 65 high energetic molecules (HEMs) were calculated from the various rules such as Kamlet-Jacobs, Kistiakowsky-Wilson, modified Kistiakowsky-Wilson, Springall-Roberts rules to calculate more accurate detonation velocity (Dv). In addition, they were applied to five kinds of detonation velocity equations proposed by K-J, Rothstein, Xiong, Stine and Keshavarz. The mean absolute error and root mean square error of HEMs were obtained from experimental and calculated velocity value for each method. The K-J and Xiong equation that is slightly complex showed a lower mean absolute error than the simple Rothstein and Keshavarz equation. When the mod-KW rule was applied to the Xiong equation, the detonation velocities were the most accurate. This study compared the various method of calculating the detonation velocity of HEMs to obtain accurate HEMs performance.