• Journal of the Korean Society of Combustion
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• v.16 no.3
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• pp.12-20
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• 2011

Oxy-coal combustion for $CO_2$ capture in coal power plants entails a mode switching from air-firing to oxyfiring. In this study, procedure of the mode switching was investigated and discussed through experiments in pilot scale facilities: (1) a 0.3 $MW_{th}$ furnace with a vertical single burner and a FGR(Flue Gas Recirculation) system (2) a 1 $MW_{th}$ furnace with horizontal 4 burners and a FGR system. Principle of the mode switching was established and performed with control of FD fan, FGR fan, ID fan and oxygen flow rates. We have found that equivalence ratio in the oxy-firing mode should be increased more than that in the air-firing to achieve stable mode switching. Control of FD, ID and FGR fans should be performed carefully in the mode switching, in the sense of complete combustion and flame attachment. Moisture contents in the ash and the flue gas recycled to the primary oxidizer stream should be removed to prevent condensation, corrosion and duct clogging.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.1
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• pp.9-14
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• 2011

Due to the improvement of science technology, the future tank system will have the multi-function for more powerful firing. and the tank, mounted this multi-function, must be lighter to maintain the mobility. Therefore, new brecoil technology would be necessary to reduce the recoil force for lighter platform. The present study covers a FOOB(Fire-Out0-Of-Battery) system that can reduce the recoil force dramatically. The firing sequence of the FOOB system is radically different from that of a conventional system. The gun is latched in out-of-battery position prior to firing. As soon as firing is occurred, the gun is unlatched and accelerated. The forward momentum is imparted to the recoiling parts. This momentum is opposed by the ballistic force imparted by firing and the recoil force and recoil length will be reduced. In this study, the ADAMS simulation has been performed with the scale model of the FIB(Fire-In-Battery) system and the FOOB system. The ADAMS simulation results show that the FOOB system could reduce the operating time and recoil length and the recoil force.

• Journal of the military operations research society of Korea
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• v.36 no.2
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• pp.11-24
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• 2010

Quick precision-strike capability of the artillery will be an important factor in modern and future war and it's represented by NCW and EBO. This study is based on artillery which has time limitation of firing, such as artillery which hides when not firing, and modeling various situations to decide firing order and who to shoot. The main purpose of this study is to suggest a mathematical programming model and a genetic algorithm which satisfies the limitation of firing time. The objective function is to minimize the total firing time to spend. The results of the suggested algorithm quickly gives a best solution for a large scale field artillery targeting problems.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.3
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• pp.259-265
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• 2009

In the traditional percussion locks of small arms, a firing pin is struck by a hammer rotating on a single center of rotation, which makes the percussion mechanism simple and reliable. In order to strike the firing pin by the hammer, however, the firing pin should be located within the radius of rotation of the hammer. As the distance between the striking point of the firing pin and the center of rotation of the hammer becomes longer, the radius of rotation of the hammer should also be increased, which results in the increase of the volume and weight of the small arms because the hammer needs the more space for its operation inside of the small arms. In this paper, a link type percussion lock was newly proposed in order to overcome the limitation of designing small arms when using traditional percussion locks, as mentioned above. The link type percussion lock was modeled by using multi-body dynamics software and designed to satisfy the requirements such as striking force level of the hammer exerting on the firing pin enough to detonate the percussion cap of ammunitions and the safety on the accidental drop. It was applied to the newly developed dual-barrel weapon system, in which the weight and overall length are important design factors, and verified by durability test and drop test on the ground.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.1
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• pp.69-75
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• 2011

Firing tests have been carried out for a technology demonstration model of 75-tonf-class combustor which is to be used on the liquid rocket engine of a Korean space launch vehicle. Firing tests were done at 50% of the nominal flow rate because of incapability of the test facility and limit of the test bed strength. Through the low pressure firing tests of 75-tonf-class channel cooling thrust chamber, operability and stability at the ignition and combustion phases were confirmed. Additionally it was foreseen that the 75-tonf-class thrust chamber would satisfy the performance requirements.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.827-832
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• 2008

One of the most important issues in AC PDP is luminance and luminous efficacy. To improve the luminance and luminous efficacy, new sustain electrode structure which contains long discharge gap is necessary. However, it causes a rise of firing voltage. In this experiment, a new structure is proposed in order to solve this problem. To drop the firing voltage, the hump shaped electrode is inserted into the forward area of the main discharge gap. The experimental results show that proposed structures with 160um discharge gap have high firing voltage by 38V, high luminance by 30% and high luminous efficacy by 15% compared with conventional type having 60um discharge gap. In addition, the proposed structure with hump electrode shows lower firing voltage by 24V compared with the test panel with 160um discharge gap which doesn't have hump electrode though they have similar luminous efficacy.

• Journal of the Korean Society of Combustion
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• v.15 no.2
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• pp.34-40
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• 2010

The effect of co-firing with pulverized coal and wood biomass on ignition and burn-out temperature was investigated at air and oxy-fuel conditions by thermo gravimetric analyzer(TGA). Three kinds of coal(shenhua, adaro, wira) were selected and mixing ratios of coal and wood biomass was set to 1, 0.5, and 0.8. The ignition temperature depended on the amount of volatile matter of blended fuel, while the burn-out temperature was dominated by the oxidant ingredients. The oxy-fuel condition with an oxygen ratio(Ofr,o) of 0.3 showed similar tendency with air condition in the heat flow measurement. Volatile matter reaction, however, became dominant when oxygen ratio exceeded 0.8 for co-firing combustion of wood biomass and pulverized coal.

• The Journal of Advanced Prosthodontics
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• v.6 no.3
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• pp.177-184
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• 2014

PURPOSE. The aim of this study was to measure the changes on the marginal and internal adaptation of zirconia based anterior fixed partial dentures after the porcelain firing process. MATERIALS AND METHODS. A total of 34 anterior fixed partial dentures using LAVA CAD/CAM system (3M ESPE, Germany) were applied. Two silicone replicas were obtained: one is obtained before porcelain firing process (initial) and the other is obtained after porcelain firing process (final), followed by the examination under a binocular stereomicroscope. Kruskal Wallis and Wilcoxon Signed Ranks tests were used for the statistical analysis (P<.05). RESULTS. No statistically significant difference was found between initial and final marginal gap values (P>.05). At the internal gap measurements, final marginal area values ($59.54{\mu}m$) were significantly lower than the initial marginal area values ($68.68{\mu}m$)(P<.05). The highest and the lowest internal gap values were observed at the incisal/occlusal area and at the marginal area, respectively. In addition, lower internal gap values were obtained for canines than for central incisors, lateral incisors and premolars at the incisal area (P<.05). CONCLUSION. The firing cycles did not affect the marginal gap of Lava CAD/CAM system, but it is controversial for the internal gap.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.6
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• pp.573-578
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• 2004

EED consists of bridgewire, explosive charge, lead pins and metal case. If a firing signal is injected to EED， the explosive charge in EED is initiated by heating of bridgewire. Electromagnetic waves radiated from high power transmitters or radars can also cause unexpected firing of EED. Therefore, EMC design and test requirements for EED in military specifications are established and applied. This report describes the characteristics of RF sensitivity fur a firing fuse which is used fur EMC test instead of a real EED installed in aircraft. RF firing level of the fuse was predicted using transmission line(TL) theory. n sensitivity and RF sensitivity specified in military specifications were measured.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.4
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• pp.94-102
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• 2011

Sub-system requirements of a pressure-fed hot-firing test facility for performance assessment of a Liquid Rocket Engine(LRE) thrust chamber using Liquid oxygen and kerosene were described. These requirements were based on the experience of construction and operation of the ground hot-firing test facility which was used for the development of the KSR-III and a 30 tonf-class LRE thrust chamber. So it is expected that this paper is used as a basic material and an itemized previous review statement for the design and construction of a large hot-firing test facility.