• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.317-322
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• 2020

Hydroxylammonium nitrate (HAN; NH₃OHNO₃) is an ionic energy material having a low melting temperature and vapor pressure with a high oxygen balance. To utilize it as an oxidizer for a high content liquid mono-propellant, a dual solvent was used to obtain HAN in a solid particulate form. The dehydrated crystal from an aqueous HAN was washed with dual organic solvents including acetone and ethanol, finally resulting in the moisture content of 13.8 wt%. When acetone was applied as a single solvent, the maximum synthesis yield of 88%, the HAN content evaluated by TGA of 86.2%, and the decomposition temperature ranged 160℃ to 205℃ were achieved.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.972-977
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• 2017

The propellant tile and crack which account for the greatest proportion of solid rockets are profoundly affected by viscosity and mechanical properties of solid propellant. In this paper solid propellant with nitrate ester polyester(NEPE) system has been researched for the viscosity, mechanical properties and burning properties with size and mixing ratio of RDX. the viscosity of propellant was changed significantly depending on the size of RDX and mixing ratio, and mechanical properties of NEPE system propellant were also varied. Considering both lower viscosity and stable mechanical properties, the optimum size and mixing ratio of RDX can be identified as the main factors to the NEPE system propellant.

• KSBB Journal
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• v.24 no.5
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• pp.463-468
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• 2009

Selenium-containing peptide (Selenium peptide) was produced by autolysis of Saccharomyces cerevisiae which was cultured in inorganic selenium-supplemented medium. Selenium peptide showed antioxidant activity and protective effects on UVB irradiated human fibroblast. Minimal toxicity of selenium peptide was observed whereas selenium nitrate exhibited cell toxicity as low as $10^{-9}\;M$. Selenium peptide also increased human fibroblast growth, procollagen type I and also decreased MMP-1 (matrix metalloprotease-1). This result showed the potential of selenium peptide as a nontoxic antioxidant.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.40-45
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• 2018

The propellant tile and crack which account for the greatest proportion of solid rockets are profoundly affected by viscosity and mechanical properties of solid propellant. In this paper solid propellant with nitrate ester polyester(NEPE) system has been researched for the viscosity, mechanical properties and burning properties with size and mixing ratio of RDX. the viscosity of propellant was changed significantly depending on the size of RDX and mixing ratio, and mechanical properties of NEPE system propellant were also varied. Considering both lower viscosity and stable mechanical properties, the optimum size and mixing ratio of RDX can be identified as the main factors to the NEPE system propellant.

• Korean Journal of Crystallography
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• v.1 no.1
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• pp.14-18
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• 1990

Econazole nitrate, 1-{2-[(4-chlorophenyl)methoxy]-2-(2,4-dichlorophenyl) ethy1}-1H-imidazole mono-nitrate.C18 H16 CI13 N3 O4 Mw=444.7 Monoclinic P/2₁c,a=17.337(4)A, b=15.191(5), c=7.601(3)A, β=91.72(2)', V=2000.9A3, Z=4, Dc=1.49g/cm3, Dm=1.45g/cm3(mo-ka)= 0.7107A, μ=4.31cm-1, F(000)=912.0, T=298'K, final R=0.061 for 1330 unique observed reflection. Each of the three ring system for the stars with B,A and C ring in order whilst A and C ring of econazole lie close to the same plane which is nearly 60˚with B ring. The hydrogen binding nitrogen of C ring and oxygen of nitrate contributes to stailization of econazole nitrate. Intr and intermolecular distances and angles are within the values recorded for simiar compounds.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.44-50
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• 2019

HNIW is a high energy material and has four crystalline phases, it is known that the thermal properties of the material depend on the crystal phase. In this sturdy, the viscosity, mechanical and burning properties of a solid propellant with nitrate ester polyester(NEPE) system with respect to the crystal phases of HNIW. According to the crystal phase of HNIW, the mechanical properties of the cured propellant did not change considerably, however differences were observed in the burning properties. Considering both a high density and stable burning properties, the optimum crystal phase of HNIW can be identified as the main factor influencing to the NEPE system propellant.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1480-1488
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• 2003

Synthesis of carbon nanomaterials on a substrate coated with metal nitrates using an ethylene fueled inverse diffusion flame was illustrated. The effects of radial distance, residence time of the substrate, and hydrocarbon composition on the synthesis of carbon nanomaterials were investigated. The effects of catalyst metal particles were also studied using SUS304 substrates coated with Fe(NO$_3$)$_3$ (ferric nitrate, nonahydrate) and Ni(NO$_3$)$_2$(nickel nitrate, hexahydrate), and Cu substrate. Carbon nanomaterials, with diameters ranging from 30 - 70 nm, were observed on the substrate for both cases of using substrates only and using them with metal nitrates. In case of using the substrate with metal nitrates, the formation and growth of carbon nanomaterials were occurred in the lower temperature region than that of using the substrates only due to the easy activation of the metal particles coated on the surface of the substrates.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.215-222
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• 2004

Synthesis of multi-walled carbon nanotubes on a nickel-nitrate-deposited substrate using an ethylene fueled inverse diffusion flame was illustrated. The deposition of nickel-nitrate particles on substrates was used for the smaller-diameter nanotubes than those formed in our previous studies. Also the effect of temperature variations on the size of formed nanotubes was investigated. The diameters of formed multi-walled carbon nanotubes were ranging from 15 to 100 nm in the several radial locations. In case of using a nickel-nitrate-deposited substrate, the smaller-diameter carbon nanotubes were synthesized than those in case of using the substrate with melted nickel-nitrate. In the formation region of carbon nanotubes, the diameter of formed nanotubes was tend to be decrease as the radial distance form the flame center was increased, that is the decreased substrate temperature.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.299-304
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• 2013

The HAN which is an ionic liquid is a non-toxic monopropellant with high storability, and its specific impulse can be increased by blending methanol, thereby it can substitute the hydrazine. The HAN was synthesized by acid-base reaction of hydroxylamine and nitric acid, and the blending ratio of HAN and methanol is 8.2:1. The iridium catalyst was used to decompose the HAN, and 1 N class thruster with shower head type injector having one orifice was used to evaluate the HAN/Methanol propellant. The thermal stability of distributor was increased by using ceramic material to endure the high temperature of product gas. The preheating temperature of catalyst should be $400^{\circ}C$ at least for the complete decomposition. The feeding pressure should be increased to increase the $C^*$ efficiency, thereby the decomposition performance was decreased upstream catalyst, and the performance of thruster was decreased. The fine metal mesh was inserted after the injector to improve the atomization of propellant, thereby it can settle the performance decrease problem. The phenomenon of performance decrease was remarkably improved owing to the insertion of fine metal mesh.

• Clean Technology
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• v.24 no.4
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• pp.371-379
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• 2018

The objective of this study is to develop a platinum/hexaaluminate pellet catalyst for the decomposition of eco-friendly liquid propellant. Pellet catalysts using hexaaluminate prepared by ultrasonic spray pyrolysis as a support and platinum as an active metal were prepared by two methods. In the case of the pellet catalyst formed by loading the platinum precursor onto the hexaaluminate powder and then adding the binder (M1 method catalyst), the mesopores were well developed in the catalyst after calcination at $550^{\circ}C$. However, when this catalyst was calcined at $1,200^{\circ}C$, the mesopores almost collapsed and only a few macropores existed. On the other hand, in the case of a catalyst in which platinum was supported on pellets after the pellet was produced by extrusion of hexaaluminate (M2 method catalyst), the surface area and the mesopores were well maintained even after calcination at $1,200^{\circ}C$. Also, the catalyst prepared by the M2 method showed better heat resistance in terms of platinum dispersion. The effects of preparation method and calcination temperature of Pt/hexaaluminate pellet catalysts on the decomposition of liquid propellant composed mainly of ammonium dinitramide (ADN) or hydroxyl ammonium nitrate (HAN) were investigated. It was confirmed that the decomposition onset temperature during the decomposition of ADN- or HAN- based liquid propellant could be reduced significantly by using Pt/hexaaluminate pellet catalysts. Especially, in the case of the catalyst prepared by the M2 method, the decomposition onset temperature did not show a large change even when the calcination temperature was raised at $1,200^{\circ}C$. Therefore, it was confirmed that Pt/ hexaaluminate pellet catalyst prepared by M2 method has heat resistance and potential as a catalyst for the decomposition of the eco-friendly liquid propellants.