• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.32 no.3
• /
• pp.66-73
• /
• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90% of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.

• Journal of Energy Engineering
• /
• v.5 no.2
• /
• pp.176-182
• /
• 1996

The effects of some additives (black liquor, NaOH, water and wood) on the conversion of coal and product were investigated in the lab-scale, high pressure reacting system around 375$^{\circ}C$. The addition of black liquor enhances the coal conversion yield about 38.6%, which is mainly due to NaOH in black liquor. Also, sulfur of the black liquor in coal liquefaction process evolved hydrogen sulfide, which causes the odor problem. Addition of water in coal liquefaction increased CO$_2$content in the gas phase, and low boiling range components in liquid products. Coprocessing of wood and coal at 400$^{\circ}C$ increased yield of liquid product about 8%, but higher temperature above 400$^{\circ}C$ reduced liquid product due to increase of gas products.

• Journal of the Korean Electrochemical Society
• /
• v.13 no.3
• /
• pp.181-185
• /
• 2010

Polyaniline-ionic liquid composite was prepared and investigated its physical and electrochemical properties. The quasi-solidification was presented in imidazolium-based ionic liquid (1-methly-3-propylimidazolium iodide, PMI-I) containing above 30 wt% of polyaniline (emeraldine base), which exhibited around 80% decrease of conductivity compared to pristine ionic liquid, resulting in fibril structure trough ${\pi}-{\pi}$ self-assembled of imidazolium aromatic ring of ionic liquid on polyaniline framework.

• Journal of the Korean Applied Science and Technology
• /
• v.31 no.3
• /
• pp.337-344
• /
• 2014

In this paper, we have examined the interaction of low bandgap polymer {poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole)(PHVTT)} with ionic liquids. Further, we have studied the temperature dependent interactions between the ionic liquids [tri-butyl methyl ammonium methyl sulfate ([TBMA][$MeSO_4$]), methyl imidazolium chloride ([MIM]Cl) and butyl methyl imidazolium chloride ([BMIM]Cl)] and polymer using UV-vis spectroscopy, FT-IR spectroscopy, photoluminescence (PL) spectroscopy, as a function of temperature at 21, 28, 32, $37^{\circ}C$. These experimental results suggest that interactions of polymer with ionic liquids ([MIM]Cl, [TBMA][$MeSO_4$]) showed weak interactions by increasing temperature but [BMIM]Cl has no significant effect with increase in temperature.

• Applied Chemistry for Engineering
• /
• v.31 no.6
• /
• pp.603-606
• /
• 2020

A hydrophilic alkaline room temperature ionic liquid electrolyte (RT-IL) carrying hydroxide ion as an anion and 1-benzyl-3-butylimidazolium as a cation was synthesized. Electrochemical, physical and structural properties of the synthesized RT-IL were characterized using cyclic voltammetry, ionic conductivity, viscosity, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), FT-IR, and 1H-NMR measurements. High ionic conductivity and low viscosity characteristics comparable to 0.1 M KCl electrolyte solution were achieved for the RT-IL in addition to a wide electrochemical potential window of about 4.4 V. The results indicate that the RT-IL is promising for future applications as an alternative electrolyte to energy and environmental research fields.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.6
• /
• pp.71-75
• /
• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale dump-cooled liquid rocket engine using LOX and kerosene as propellants. The nozzle of the rocket engine was film cooled with water as coolant. A special film cooling adapter was fabricated to introduce the film-coolant into the thrust chamber. The flow rates of film coolant was approximately 15~19 percent of the total propellant. The nozzle heat flux was determined from the measured temperature rise and flow rate of the coolant(water). Large reductions in the nozzle heat flux was resulted when film cooling adapter located directly upstream of the nozzle.

• Analytical Science and Technology
• /
• v.5 no.4
• /
• pp.381-387
• /
• 1992

Optimum counting condition of a low level liquid scintillation counter for radiocarbon dating has been determined to minimize the contribution of tritium activity and get the highest FOM by the variation of scintillation solutions, scintillation solution to benzene ratio, and ${\beta}$-ray spectrum counting ranges. Under the condition, background count rate has been reduced to $2.26{\pm}0.03cpm$, and the maximum measurable age reached to about 40,000 years. And the practicality of counting system has been verified by the analysis of shell and peat samples.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.877-880
• /
• 2011

A coaxial swirl/shear injector using GCH4/LOx as propellants was degisned and manufactured. Flow analysis by Fluent was performed to decide the number of orifice and the rear shapes of inlet orifice etc. Flow rate of the injector was measured according to differential pressure and uniformity of injector's spray pattern was confirmed by a patternator. The results showed that the difference of flow rate was around 10% and the spray angle of oxidizer was $66^{\circ}$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.658-661
• /
• 2011

A coaxial swirl/shear injector using GCH4/LOx as propellants was degisned and manufactured. Flow analysis by Fluent was performed to decide the number of orifice and the rear shapes of inlet orifice etc. Flow rate of the injector was measured according to differential pressure and uniformity of injector's spray pattern was confirmed by a patternator. The results showed that the difference of flow rate was around 10% and the spray angle of oxidizer was $66^{\circ}$.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.337-337
• /
• 2010

하나로 반사체의 수직공 안에 설치된 냉중성자원 시설계통의 수조내기기는 원자로에서 생성되는 열중성자를 약 22K의 감속재로 감속시켜 0.1~10 meV 범위에서 높은 선속을 갖는 냉중성자를 생산한다. 냉중성자를 생산하기 위한 냉중성자원 시설계통의 구성은 감속재인 수소를 포함하고 있는 수소계통, 수소의 외부누출을 방지하기 위한 가스블랭킷계통, 극저온의 액체수소를 생산하기 위한 헬륨냉동계통, 극저온인 액체수소 층을 감속재용기 내에 유지하기 위한 진공계통 등으로 되어있다. 이들 계통 중 진공계통은 냉중성자원 시설계통의 정상운전 시 액체수소 열사이펀, 감속재용기 등의 냉중성자원 극저온 부품의 단열을 위하여 진공용기의 내부 진공도를 공정진공도 이하로 유지하기 위한 계통이다. 정상운전 시 진공계통으로부터 발생되는 배기 가스는 배기 수집탱크에 포집된다. 냉중성자원 시설계통으로부터 발생되는 배기가스는 배기수 집탱크를 통하여 수소의 누출여부를 확인한 후 원자로홀로 배기되도록 되어 있으며, 만일의 경우 탱크내부의 배기가스 수소 농도가 기준치인 3.5%이상일 때는 유입 원을 자동으로 차단하고, 희석용 가스인 고압의 질소를 주입하여 수소의 농도를 기준치 이하로 낮춘 후 원자로 홀로 자동 배출하도록 되어 있다. 본 논문에서는 냉중성자가 생산되는 냉중성자원 시설계통의 운전과정에서 진공계통으로부터 배출되는 배기가스를 배기수집탱크로 포집하고, 이 가스에 대해 수소가스의 농도를 분석하여 원자로 홀로 안전하게 배기할 수 있도록 수행된 수소가스 분석에 대해 기술하였다.