• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.340-343
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• 2011

Explosive bolts are reliable and efficient mechanical fastening devices having the special feature of a built-in release. The disadvantage of explosive bolt lies in that it is based on the high explosive effect of a pyrotechnic charge. The aim of the present work is to propose a pyrotechnically releasable mechanical linking device for two mechanical elements that does not suffer from such drawbacks. The pyro-lock using the pressure cartridge has the release characteristic without fragmentation and minimum pyro-shock. The present work is focused on the design, the interpretation of structure, the separation mechanism, separation force, and the results of various tests.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.253-258
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• 2020

Petrochemical industry complex in Korea always has high riskiness due to explosive and inflammable gases. To prevent these explosion, most facility of petrochemical industry complex requires the performance of explosive proof. The control panel, which is used as explosive proof, has been used the air injection method by manually from outside to constantly keep the temperature and pressure between inside and outside of the panel. In this paper, we propose the automatic temperature controller, which performs automatic heating and cooling according to temperature inside the panel in order to control temperature automatically.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.100-106
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• 2014

High strength concrete has a structural advantage as well as superior usability and durability, so that its application in building is being steadily augmented. However, in the high temperature like in a fire, the high strength concrete has extreme danger named explosive spalling. It is known that the major cause of explosive spalling is water vapour pressure inside concrete. General solution for preventing concrete from spalling include applying fire protection coats to concrete in order to control the rising temperature of members in case of fire. The purpose of this study is to investigate the high temperature properties of fireproof mortar using organic fiber and various types of fine aggregate for fire protection covering material. The results showed that addition of perlite and polypropylene fiber to mortar modifies its pore structure and reduces its density. This causes the internal temperature to rise. As a results, it is found that a new fireproof mortar can be used in the fire protection covering material in high strength concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.11a
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• pp.22-23
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• 2015

For the facility using explosive gas, it is very important to use anti-explosive structure. Therefore, using FRC of high stiffness should be used, but the research on actual application under the construction conditions is not sufficient. Hence, in this research, based on the case study on application of FRC for anti-explosive structure, the strength characteristics of FRC with combined fibers were evaluated comparing between before and after the pumping.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.3
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• pp.280-284
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• 2011

The mass change during the molecular interaction between explosive specific bio-receptors and target molecules has been measured using quartz crystal microbalance(QCM), which has a mass change detection limit up to ~ng/$cm^2$. The environmental effect on the molecular interaction has been evaluated. In the liquid phase molecular interaction experiments, the high selectivity of the bio-receptor to DNT compared with toluene has been shown and the sensitivity for various concentrations of DNT has been demonstrated.

• Journal of Korean Society for Atmospheric Environment
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• v.33 no.5
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• pp.521-528
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• 2017

In the combustion treatment of explosive gases with a high heating value such as $H_2$ and $NH_3$ used in semiconductor and chemical processes, the heat recovery modeling and exergy analysis of the process using the Aspen Plus simulator and its thermodynamic data were performed to examine the recovery of high temperature thermal energy. The heat recovery process was analyzed through this process modeling while the exergy results clearly confirmed that the rigorous reaction mainly occurs in the condenser and the chamber. In addition, the process modeling demonstrated that approximately 95% of the exergy is destructed on the basis of the exergies injected and the exergy being exhausted. Using the exergy technique, which can quantitatively analyze the energy, we could understand the energy flow in the process and confirm that our heat recovery process was efficiently designed.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.1
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• pp.43-51
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• 2020

In this study, numerical analysis was carried out on a complex pressure field of blast waves caused by the detonation of high explosives in various environments. The generated blast waves propagated in the air, upon the sudden release of high energy induced by the explosion. Reflected waves were created when the pressure waves encountered certain obstacles such as the ground or the walls of structures. The propagation of the blast waves and its interaction with the reflected waves were simulated. An adaptive mesh refinement was applied to improve the efficiency of distribution of computer resource, for the computational calculation of the blast wave propagation in a wide open space. In addition, the integration of the calculation domains for the explosive and air were considered when the maximum density of the explosive region was below critical value. The results were verified by comparison with the pressure time history from blast wave experiments performed under two topographical conditions.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.736-742
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• 2000

Mass removed from crystalline silicon samples during high power single-pulse laser ablation was studied by measuring the resulting crater morphology with a white light interferometric microscope. The volume and depth of the craters show a strong nonlinear change as the laser irradiance increases across a threshold value, that is, approximately $2.2{\times}10^{10}\;W/cm^2$. Time-resolved shadowgraph images of the ablation plume show the ejection of large particulates from the sample for laser irradiance above the threshold, with a time delay of about 300-400 nsec. The thickness of superheated liquid layer near the critical temperature was numerically estimated, considering the transformation of liquid metal into liquid dielectric near the critical state (i.e., induced transparency). The estimated thickness of the superheated layer at a delay time of 200 nsec agreed with the measured crater depths, suggesting that induced transparency promotes the formation of a deep superheated liquid layer which leads to an explosive boiling responsible for the sudden increase of crater volume and depth.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.6
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• pp.857-866
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• 2013

This paper is concerned with the material properties of functional high explosive(FHX) simulant at various strain rates ranging from $10^{-4}/sec$ to $10^1/sec$. Material properties of FHX at high strain rates are important in prediction of deformation modes of FHX in a warhead which undergoes dynamic loading. Inert FHX stimulant which has analogous mechanical properties with FHX was utilized for material tests due to safety issues. Uniaxial tensile tests at quasi-static strain rates ranging from $10^{-4}/sec$ to $10^{-2}/sec$ and intermediate strain rates ranging from $10^{-1}/sec$ to $10^1/sec$ were conducted with JANNAF specimen using a tensile testing machine, INTRON 5583, and developed high speed material testing machine, respectively. Uniaxial compressive tests at quasi-static strain rates and intermediate strain rates were conducted with cylindrical specimen using a dynamic materials testing machine, INSTRON 8801. And cyclic compressive loading tests were performed with various strain rates and strains. Deformation behaviors were investigated using captured images obtained from a high-speed camera.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.210-210
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• 2003