• Journal of the Korean Vacuum Society
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• v.2 no.4
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• pp.480-485
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• 1993

Factros considered building the magnetron sputtering system for TFT LCD (thin film transistor liquid crystal display0 metallization were thin film thichnes uniformity, temperature uniformity and the pressure gradient of sputtering gas flow in vacuum chamber, base pressure, and the stability fo the carrier moving . The system was consisted of a deposition chamber, a pre-heating chamber, a RF-precleaning chamber and a load/unload lock chamber. The system was designed to handle a substrate with dimension of 400$\times$400mm. The temperautre uniformity of a heater table developed showed $250 ^{\circ}C\pm$5% accuracyon the substrate glass. A base pressure of 1.8 $\times$10-7 torr was obtained after 24 hours pumping with a cryo pump. After an aluminum target was installed in a sputtering source and the film wa sdeposited on the glass, the uniformity, reflectivity and sheet resistance of the deposited film were measured.

• Development and Reproduction
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• v.1 no.2
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• pp.173-180
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• 1997

This study has been conducted to investigate the molting behavior and the effects of rearing temperature and day length on molting in the behavior and the effects of rearing temperature and day length on molting in the giant freshwater prawn, Macrobrachium rosenbergii reared in the laboratory. The results obtained were summarized as follow: 1. After pre-spawning molting, the protopodites of 1st, 2nd, 3rd, and 4th except 5th pleopod bore new breeding setae which conserve eggs in the brooding chamber and the basis of 3rd, 4th, and 5th pereiopods bore new breeding dresses which transport the ovulated eggs into the brooding chamber. 2. Adult females reared in 27.5-$29.4^{\circ}C$ molted 10-12 times per year at interval of 27-35 days, of which four or six moltings were common molting for growth and another four or five moltings were pre-spawning molting for spwaning and brooding. In winter season, pre-spawning molting did not happen to most of adult females in spite of the same temperature. 3. Duration of intermolt cycle was 31-38 days and 26-30 days at 25.3- $26.5^{\circ}C$ and 28.7- $30.4^{\circ}C$ of rearing temperature, respectively.

• Journal of the Korean Society of Combustion
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• v.9 no.1
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• pp.25-31
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• 2004

Various types of the air/fuel pre-mixer have been designed and tested to investigate the combustion characteristics of the lean-premixed gas turbine combustor, such as NO emission and flame stability. One type of the pre-mixers has been selected and installed to a 70 kW lean-premixed gas turbine combustor. The concentrations of CO and NO were measured with varying equivalence ratios in the combustion chamber at ambient pressure. The result shows that the emissions of CO and NO are heavily affected by the shape of the pre-mixer. The NO and CO emissions decreased, as the mixing ratio of air and fuel increased. In addition, the NO emission of the lean-premixed low NOx combustor is more dependent on the equivalence ratio than that of the conventional combustor.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.1
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• pp.30-38
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• 1993

In this study, the combustion characteristics in a pre-combustion chamber diesel engine was investigated with experimental conditions of marine engine load. The heat release analysis used was a single-zone single-chamber thermodynamic analysis based on pre-combustion chamber pressure-time data. Based on the results of this investigation, the following conclusions were reached: 1) Increasing the load, peak pressure was increased and position of P sub(max) was retarded in crank angle degrees. 2) Ignition delay time was almost constant without relating to the load and the heat values to form a combusitible mixture were decreased apparently with increasing the load. 3) In premixed-combustion mode, the pattern of heat release rate was resembled without relating to the load and premixed-combustion time was shortened with increasing the load. 4) Increasing the load, mass of premixed-burned fuel was increased slightly, but was invariable beyond a certain fuel-air ratio. 5) Increasing the load, premixed-burned fraction was decreased.

• Journal of the Korean Society of Combustion
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• v.4 no.1
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• pp.141-153
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• 1999

Numerical analysis for the combustion flow in the combustion chamber of incineration system has been carried out in order to acquire the basic design capability of incineration system. Established mathematical model was applied to the performance prediction of the pre-designed combustion chamber of commercial plant. Especially, combustion characteristics and the variation of flow pattern have been deeply discussed in accordance with secondary air injection. Secondary air injection was effective for the turbulent mixing between air and carbon monoxide/volatile matter resulting in considerably reduced CO content at the exit. Secondary air injection was found to be one of the key design parameters because the size of recirculation zone could be changed with the variation of injection characteristics.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.244-248
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• 2012

A series of hybrid rocket combustion experiments were carried out with PMMA/GOx changing diameter and length of the disk installed at pre-chamber. The disk can generate vortex shedding flow and change flow conditions prior to entering the fuel grain which could also alter the combustion characteristics and pressure oscillations. The interaction of vortex shedding in the pre-chamber and small-scale vortices adjacent to burning surfaces by using combustion test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.265-268
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• 2005

A series of ignition tests had been conducted for a thrust chamber propelled by Jet A-1 and liquid oxygen with a chamber pressure of 52.5 bara and a thrust of 30 tonf. The chamber ignited by a hypergolic fluid, TEAL, keeps its first constant pressure low at $63\%$ of the design value by $61\%$ of a liquid oxygen mass flow rate and $67\%$ of fuel for 0.25 sec. The operating O/F ratio of the chamber was kept at lower values than that of the design operating condition throughout the whole ignition procedure. Surge of the chamber pressure is below $6\%$ of the design value.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.469-473
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• 2010

In this study, combustion tests using liquefying fuels with fast regression rate were performed. The chamber pressure oscillation was analyzed and hazards of combustion instabilities were examined. In case of Liquefying fuel with fast regression rate, the amplitude of chamber pressure oscillation was increased compared to the polymeric fuels. However, the critical combustion instability can hardly occur in liquefying fuel. This is because the rapid change of inner chamber diameter limits the amplification of chamber pressure oscillation. The chamber pressure oscillation due to the large increase of fuel production and the vortex shedding in pre-chamber violently occurs during combustion using single-port axial injector.

• Journal of Mechanical Science and Technology
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• v.20 no.6
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• pp.874-881
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• 2006

Combustion stability characteristics in actual full-scale combustion chamber of a rocket engine are investigated by experimental tests with the model (sub-scale) chamber. The present hot-fire tests adopt the combustion chamber with three configurations of triplet impinging-jet injectors such as F-O-O-F, F-O-F, and O-F-O configurations. Combustion stability bound-aries are obtained and presented by the parameters of combustion-chamber pressure and mixture (oxidizer/fuel) ratio. From the experimental tests, two instability regions are observed and the pressure oscillations have the similar patterns irrespective of injector configuration. But, the O-F-O injector configuration shows broader upper-instability region than the other configurations. To verify the instability mechanism for the lower and upper instability regions, air-purge acoustic test is conducted and the photograph or the flames is taken. As a result, it is found that the pressure oscillations in the two regions can be characterized by the first impinging point of hydraulic jets and pre-blowout combustion, respectively.

• Journal of Advanced Marine Engineering and Technology
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• v.11 no.3
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• pp.31-44
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• 1987

Nowadays, the problems of energy and environmental pollution become serious day by day and the diesel engine, which has been proved to be superior to gasoline engine with respect to fuel consumption and ecological problems of exhaust gas, has been adopted widely for various purposes from the marine diesel engine and the dynamo engine to all kinds of engine on land. Therefore, extensive parametric studies on combustion of diesel engine should be done for its desing and improvement. To predict the behavior of diesel engien according to variable operating conditions by means of cycle simulation, the reasonable pattern of heat release rate has to be asumed. But it is necessary to know the actual variation of heat release rate in order to assume the reasonable pattern of heat release rate according to the actual operating conditions. In this paper, on a high speed small bore diesel engine with pre-combustion chamber, experimental investigations were carried out to determine the relationship between the heat release pattern and parameters such as engine load and speed. And also, the theoretical investigations about the performance variations of the above diesel engine according to the predicted pattern of heat release rate variation were performed. From the above observations, it may be said that the Fanboro indicator, which was used to get the cylinder pressure, can be used to estimate a reasonable pattern of heat release rate and it is confirmed that the pattern of heat release rate for the pre-combustion type engine is different from that of the direct injection type engine.