• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2005.11a
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• pp.81-85
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• 2005

Recently, fire resistance of high performance concrete for explosive spalling was issued as high performance concrete was vulnerable to the explosive spalling in initial fire. Therefore, in this study, an experiment about reduction effect to explosive spalling of high performance concrete is performed by adding several polymer fiber with various volume fraction, an then final fiber and volume fraction of that which reduce the explosive spalling of high performance concrete is presented. As the result of this study, the most fitted fiber volume fraction of reducing effect for explosive spalling at high performance concrete is under the 0.1%, as consider the flowability and efficiency.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.543-550
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• 2017

Various chemical properties including density and heat of formation of 1-substitued trinitroimidazoles (TNIs) were estimated by using density functional theory (DFT). Using chemical properties estimated by DFT, explosive performance and sensitivity of 1-substitued TNIs were analyzed by following the ADD Method-1 procedure. The results were displayed on two-dimensional performance-sensitivity plot, and were compared with those of explosive molecules commonly used in many military systems. Different 1-substituents of TNI made that both explosive performance and impact sensitivity were changed significantly. Methyl substituted TNI became moderately insensitive and slightly less powerful. Amino, fluoro, picryl, and difluoroamino substituted TNIs were highly powerful like RDX and HMX, but greatly sensitive. Nitro substituted TNI was predicted to be extremely sensitive to be handled as a secondary explosive.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.797-800
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• 2006

Normally, Structural light-weight aggregate concrete(LWC) has been main used in high rise building with the object of wight loss. In spite of LWC have the advantage of light-weight, limit the use of strength restrictions by reason that explosive spalling in fire. Especially, LWC is occurred serious fire performance deterioration by explosive spalling. Thus, this study is concerned with fire performance of LWC for the purpose of using PP fibers prevent to explosive spalling. From the experimental test result, LWC is happened explosive spalling.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2006.04a
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• pp.172-175
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• 2006

Recently, fire resistance of high performance concrete for explosive spatting was issued as high performance concrete was vulnerable to the explosive spatting in initial fire. Therefore, This study is willing to propose fundamental data for quick and accurate diagnosis of deteriorated concrete structure by fire damage with making variable concrete test specimen, exposing high temperature environment, observing the explosive spatting and examining engineering property.

• Journal of Internet Computing and Services
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• v.23 no.4
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• pp.11-19
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• 2022

This paper is a study to evaluate the performance when classifying explosive components by capacity using a convolutional neural network (CNN). Among the existing explosive classification methods, the IMS steam detector method determines the presence or absence of an explosive only when the explosive concentration exceeds the threshold set by the user. The IMS steam detector has a problem of determining that even if an explosive exists, the explosive does not exist in an amount that does not exceed the threshold. Therefore, it is necessary to detect the explosive component even when the concentration of the explosive component does not exceed the threshold. Accordingly, in this paper, after imaging explosive time series data with the Gramian Angular Field (GAF) algorithm, it is possible to determine whether there are explosive components and the amount of explosive components even when the concentration of explosive components does not exceed a threshold.

• Analytical Science and Technology
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• v.28 no.6
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• pp.430-435
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• 2015

Two-dimensional analysis between the explosive performance and the impact sensitivity for methylnitroimidazole derivatives was performed to understand where these new energetic molecules could be utilized. The explosive performance was analyzed with the Cheetah program, while the impact sensitivity was predicted using neural network analysis. Successive nitration of methylimidazole made the molecule more sensitive, but methyltrinitroimidzole appeared to have a relatively good safety characteristic. We recently developed a novel method to analyze the potential usage of new energetic molecules using a two-dimensional chart, where the explosive performance and the impact sensitivity were located on the X-axis and Y-axis, respectively. An analysis of a two-dimensional plot between the performance and the sensitivity indicated that methyldinitroimidazole would be useful for insensitive explosive formulations, while methyltrinitroimidazole was forecasted for use as an ingredient for high explosive formulations.

• Bulletin of the Korean Chemical Society
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• v.32 no.7
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• pp.2319-2324
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• 2011

Molecular structures and chemical properties of 1-aminoimidazole derivatives have been investigated at high levels of density functional theories. Heat of formation, density, explosive performances and impact sensitivities have been estimated at the global minimum of potential energy surface. As more nitro groups are introduced, the explosive performances of 1-aminoimidazole derivatives are enhanced, while the impact sensitivity becomes more sensitive. A two-dimensional plot between explosive performance and impact sensitivity has been utilized to comprehend the technical status of new explosive candidates. Based on locations in the two-dimensional plot, 1-aminodinitroimidzole isomers appears to have a potential to be good candidates for insensitive explosives, and 1-aminotrinitroimidazole may become a powerful explosive molecule whose behavior is quite close to HMX.

• Analytical Science and Technology
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• v.28 no.5
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• pp.347-352
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• 2015

Chemical properties such as heat of formation and density of methylnitroimidazole derivatives were predicted and analyzed by using density functional theory (DFT). Successive addition of energetic nitro groups into an imidazole ring increases both the heat of formation and the density. Using the chemical property values computed by DFT, explosive performance was analyzed with the Cheetah program, and compared with those of TNT, RDX, and HMX, which are currently used widely in military systems. When both C-J pressure and detonation velocity were used as explosive performance, methyldinitroimidazole derivatives show better performance than TNT, while methyltrinitroimidzole is almost close to RDX. Since methylnitroimidazole derivatives have a good merit, i.e. low melting point for melt loading, they are forecasted to be used widely in various military and civilian application.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.269-275
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• 2020

An explosive bolt is one of many representative pyrotechnic release devices that separates two joined structures using explosives inside the bolt. In this study, a 1/2 inch ridge-cut explosive bolt with an EBW detonator was developed for usage in sled tests. The initial shape design was carried out based on the design method, and the performance test showed that the separation performance was outstanding but fragments occurred. Therefore, numerical analysis was performed to reduce the amount of debris by minimizing the amount of explosives. From the numerical analysis, the separation mechanism and characteristics of the ridge-cut explosive bolts were identified, and the minimum amount of explosives that does not generate debris was proposed. Verification tests revealed that the ridge-cut explosive bolts with the proposed explosive weight minimized fragments while maintaining the separation performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.521-524
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• 2005

This study is an experiment for reducing effect of explosive spalling by fiber addition ratio and kinds of fiber at high performance concrete. So, high strength concrete were made addition to PVA and PP fiber as diameter of 34, 100 $\mu$m and 40 $\mu$m by fiber addition ratio as 0.05, 0.1, 0.3$\%$. After those were heated respectively for 30 in accordance with Standard Time-Temperature Curve. And then conditions of explosive spalling were divided into four grades, and characters of explosive spalling were investigated.