• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.60-63
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• 2008

Phase change in combustion of energetic materials happens inevitably. The product gas generated by combustion is at extreme temperature and pressure state. The interaction between a gas and metal generates high strain rate deformation and complex wave phenomena. In order to perform combustion simulation containing phase changes, we develop an elegant model for phase change and provide a proof of performance via vapor explosion example.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.6
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• pp.97-104
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• 2013

N-Guanylurea dinitramide (GUDN) is an energetic material with low sensitivities and good performance for use as propellants or insensitive munitions explosives. The efficient synthesis and characterization of high energy density material of GUDN is reported. GUDN was characterized spectroscopically as well as elemental analysis. In addition, the heats of formation were calculated with the Gaussian 09 suite of programs. For initial safety testing, the impact sensitivity and the friction sensitivity were tested following BAM procedure.

• Journal of Electrochemical Science and Technology
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• v.7 no.3
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• pp.190-198
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• 2016

Application of fuel cell to produce renewable energy for commercial purpose is limited by the high cost of Pt based electrode materials. Development of inexpensive, high energetic electrode is the need of the hour to produce pollution free energy using bio-fuel through a fuel cell. Ni-Cu and Ni-CeO₂-Cu electrode materials, electro synthesized by pulse current have been developed. The surface morphology of the electrode materials is controlled by different deposition parameters in order to produce a high current from the electro-oxidation of the fuel, the ethanol. The developed materials are electrochemically characterized by Cyclic Voltammetry (CV), Chronoamperometry (CA) and Potentiodynamic polarization tests. The results confirm that the high current is due to their enhanced catalytic properties viz. high exchange current density (i₀), low polarization resistance (R_p) and low impedance. It is worthwhile to mention here that the addition of CeO₂ to Ni-Cu has outperformed Pt as far as the high electro catalytic properties are concerned; the exchange current density is about eight times higher than the same on Pt surface. The morphology of the electrode surface examined by SEM and FESEM exhibits that the grains are narrow and sub spherical with 3D surface, containing vacancies in between the elongated grains. The fact has enhanced more surface area for electro oxidation of the fuel, giving rise to an increase in current. Presence of Ni, CeO₂, and Cu is confirmed by the XRD and EDXS. Fuel cell fabricated with Ni-CeO₂-Cu material electrode is expected to produce clean electrical energy at cheaper rates than conventional one, using bio fuel the derived from biomass.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.525-530
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• 2008

We present a model for simulating high energy laser heating and ignition of confined energetic materials. The model considers effect of ablation of steel plate with long laser pulses and continuous lasers of several kilowatts and the thermal response of well-characterized high explosives for ignition. Since there is enough time for the thermal wave to propagate into the target and to create a region of hot spot in the high explosives, electron thermal diffusion of ultra-short(femto- and pico-second) lasing is ignored; instead, heat diffusion of absorbed laser energy in the solid target is modeled with thermal decomposition kinetic models of high explosives are used. Numerically simulated pulsed-laser heating of solid target and thermal explosion of cyclotrimethylenetrinitramine(RDX), triaminotrinitrobenzene(TATB), and octahydrotetranitrotetrazine(HMX) are compared to experimental results. The experimental and numerical results are in good agreement.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.51-54
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• 2008

Various types of beam distributions of high energy lasers are classified by the mode patterns. We study two dimensional laser initiation of confined energetic materials with multiple beam profiles.

• Journal of Powder Materials
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• v.24 no.3
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• pp.242-247
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• 2017

In this study, the electroless nickel plating method has been investigated for the coating of Ni nanoparticles onto fine Al powder as promising energetic materials. The adsorption of nickel nanoparticles onto the surface of Al powders has been studied by varying various process parameters, namely, the amounts of reducing agent, complexing agent, and pH-controller. The size of nickel nanoparticles synthesized in the process has been optimized to approximately 200 nm and they have been adsorbed on the Al powder. TGA results clearly show that the temperature at which oxidation of Al mainly occurs is lowered as the amount of Ni nanoparticles on the Al surface increases. Furthermore, the Ni-plated Al powders prepared for all conditions show improved exothermic reaction due to the self-propagating high-temperature synthesis (SHS) between Ni and Al. Therefore, Al powders fully coated by Ni nanoparticles show the highest exothermic reactivity: this demonstrates the efficiency of Ni coating in improving the energetic properties of Al powders.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.5
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• pp.53-59
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• 2019

Solid fuel reacts with an oxidizer during combustion of a propellant to increase performance. Representative solid fuels are aluminum, cyclotrimethylenetrinitramine (RDX) and octahydro-1, 3,5,7-tetra nitro-1,3,5,7-tetrazocin (HMX). During combustion, these compounds generate white smoke by reacting with moisture and produce materials that are harmful to the environment, such as carbon monoxide, carbon dioxide, and methane gas. This study prepared a high-nitrogen-containing energetic material, hydrazinium 5-aminotetrazolate (HAT), which could be applied as a solid fuel. The compound was characterized by nuclear magnetic resonance (NMR) spectroscopy, and a thermal analysis was measured by differential scanning calorimetry (DSC). Also, the specific impulses and volumes of detonation gases were calculated using the EXPLO5 program.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.274-278
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• 2011

We present an innovative method of multi-physics application involving energetic materials. We use an Eulerian methodology to address these problems. We have devised a new level set based tracking framework that can elegantly handle large gradients typically found in energetic response of high explosive and metals. Proper constitutive relations are employed to model the transient phases of gas, lliquid, and solid in the high strain rate regime. We use the confined and unconfined rate stick results to validate against the experimental data.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.5
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• pp.591-598
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• 2018

The reaction characteristics of aluminum-copper(II) oxide composites initiated by the electrostatic discharge were studied as changing the aluminum particle size. Three different sizes of aluminum particles with nano-size copper(II)-oxide particle were used in the study. These composites were manufactured by two methods i.e. a shock-gel method and a self-assembly method. The larger aluminum particle size was, the less sensitive and less violent these composites were based on the electrostatic test. On the analysis of high speed camera about ignition appearances and burning time, the burning speed was faster when aluminum particle size was smaller.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.3
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• pp.41-46
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• 2020

In this study, measurement and analysis results from Differential scanning calorimetry(DSC) and Thermogravimetric analysis(TGA) on the newly developed high-energy thermoplastic elastomer(ETPE) propellant are described, followed by the previous study done under the same title as this paper [1]. The characteristics of high-energy thermoplastic propellant were also verified by conducting thermal analysis, and the LSGT, Shotgun & RQ Bomb test, was carried out as well. High energetic thermoplastic binders containing 45% of GAP(Glycidyl Azide Polymer), energetic plasticizer(DEGDN) and Oxidizer Aonium Perchlorate), RDX(reseach development explosive, cyclotrimethylenetrinitramine) were used to formulate the propellant.