• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.49-59
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• 2002

For the purpose of helping development of a GDI(Gasoline Direct Injection) engine, the spray behaviors and fuel distributions were investigated in a single cylinder GDI engine. The experimental engine is a swirl type GBI engine with a SCV(Swirl Control Valve). PLIF(Planar Laser Induced Fluorescence) system with KrF Excimer laser was used for the measurement of the fuel distributions. The effects of SCV opening angle and the Injector specifications, such as the spray cone angle and the offset an91e on the fuel distributions characteristics were investigated. As a result, it was found that the SCV opening angle had a great effect on the fuel distributions in the late stage of compression process by changing flow fields in the combustion chamber.

• 한국분무공학회지
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• 제2권4호
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• pp.1-6
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• 1997

In the case of analyzing the combustion phenomena in a small high speed DI diesel engine, one demands the experimental results of the impinging spray on the wall as a basic characteristics. In the experiments presented here, diesel fuel oil was injected into a high pressure chamber in which compressed air at room temperature was charged. The single spray was impinged on a flat wall. The growth of the spray was photographed with transmitted light or scattered light. The effect of the spray axis angle to the wall on the impinging spray was revealed. Finally, the experimental results was presented, that is, the radius and height of the impinging spray was influenced by above mentioned variable.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1995년도 Proceedings of the Korea Automation Control Conference, 10th (KACC); Seoul, Korea; 23-25 Oct. 1995
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• pp.79-82
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• 1995

The problem of temperature control for rapid thermal processing (RTP) in semiconductor manufacturing is discussed in this paper. Among sub=micron technologies for VLSI devices, reducing the junction depth of doped region is of great importance. This paper investigates existing methods for manufacturing wafers, focusing on the RPT which is considered to be good for formation of shallow junctions and performs the wafer fabrication operation in a single chamber of annealing, oxidation, chemical vapor deposition, etc., within a few minutes. In RTP for semiconductor manufacturing, accurate and uniform control of the wafer temperature is essential. In this paper, a robustr controller is designed using a recently developed optimization technique. The controller designed is then tested via computer simulation and compared with the other results.

• Journal of Advanced Marine Engineering and Technology
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• 제8권2호
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• pp.88-97
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• 1984

The combustion process and the performance of a diesel engine are considerably affected by the characteristics of fuel spray. It is known that the spray of swirl nozzle for diesel engine injector of small orifice ratio becomes soft spray that has no core, therefore its penetration, one of the characteristics of spray becomes werse inspite of its good dispersion. In this paper, the spray characteristics of variously designed swirl nozzle for diesel injector were investigated by the photographic method. The nozzles, used in this experiment, vary in the diameter of swirl chambers and orifice ratio. From the results of the study, the sprays of this type nozzle of optimum swirl chamber and orifice ratio show that penetration decreased slightly but dispersion and spray volume increased remarcably, compared with unswirled single hole nozzle of the same size. It was suggested as a reason for the results, that the spray of this type swirl nozzle is similar to hard spray, therefore the core of the spray sustains good penetration considerably.

• 대한기계학회논문집
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• 제17권7호
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• pp.1851-1863
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• 1993

A procedure for the prediction of the off-design performance of a gas turbine engine is proposed. The system performance at off-design speed is predicted by coupling the thermodynamic models of a compressor and a turbine. The off-design performance of a compressor is obtained using the stage-stackimg method, while the Ainlay-Mathieson method is used for a turbine. The procedure is applied to a single-shaft gas turbine and its predictability is found satisfactory. The results also show that the net work output increases with the increase of the turbine inlet temperature, while the thermal efficiency is marginal. The maximum thermal efficiency at design point is obtained between the highest pressure ratio and design pressure ratio.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.121-125
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• 2001

We study the feasibility of synthesizing Si particles using PLA method. In the previous studies, it was possible to control the size of Si nanoparticles by the He gas pressure. In this study, we fabricated sub-micron size Si particles with various shapes such as conical, hexagonal, and ring by controlling not only the ambient gas pressure but also the laser energy density. Furthermore, we found that the conical Si particles were uniform-sized and had step shape when observed from FE-SEM and AFM. The conical Si particle has the same crystal structure as the bulk single crystalline Si by the analysis of the Raman scattering. It is shown that the relationship between the laser energy density and the He gas pressure inside the chamber affects the shape of the Si particle.

• 한국정밀공학회지
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• 제27권12호
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• pp.107-112
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• 2010

A gas turbine consists of an upstream compressor and a downstream turbine with a combustion chamber, and also the compressor and the turbine are generally coupled using a single shaft. Large scale gas turbine compressor is designed as multi-stage axial flow and the blade is fan-type which is thick and wide. Recently radial cracking happens occasionally at the compressor blade tip of large scale gas turbine. So, FEM was performed on the compressor blade and vibration modes and dynamic stresses were analyzed. According to the analysis, 9th natural frequency mode of the blade, which is 2 strip mode, is near the vane passing frequency by the vane located at the upstream of the blade.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.892-897
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• 2003

This study deals with the performance of a simplified test apparatus for measurement of sound insulation of panels. In order to investigate its performance, results from experiment and theory of the sound transmission loss for single and double panels are compared. Comparative results show that in evaluation of the sound insulation performance, the test apparatus has a cumbersome problem at the low frequency region, i.e. below 315 ㎐, presumably because of the poor diffuse sound field in the chambers. Meanwhile at the high frequency, it shows a considerable results comparable to the theoretical prediction. One of the objective of this study that compares measured results between a real reverberation chamber and a simplified test apparatus, by using a specimen of a sandwich panel. It shows qualitatively resonable agreement from which one can find a potential to provide a design tool.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.34-43
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• 2001

Analysis and control of intake charge motion such as swirl and tumble are very important to improve the performance of gasoline engines. In this paper, single frame double exposure PTV(particle tracking velocimetry) is used to investigate intake flow characteristic in a steady flow test rig of gasoline engine with 2-valve and pent-roof combustion chamber. To validate this PTV method, we confirmed reliability of this PTV method using chopper, and coaxial burner experiments. The velocity Held of intake flow is measured with the intake valve lift variation. It is shown that maximum flow velocity is increased and tumble flow become stronger than inverse tumble flow as valve lift increase.

• 한국약용작물학회지
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• 제11권4호
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• pp.316-320
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• 2003

A protocol is described for rapid multiplication of Zanthoxylum piperitum DC. (Rutaceae), an important aromatic and medicinal plant, through shoot-tip explant cultures. Murashige and Skoog (MS) medium supplemented with various concentrations of N-6-benzyladenine (BA), N-6-benzylaminopurine (BAP) and thidiazuron (TDZ), in single or in combination with ${\alpha}-naphthaleneacetic$ acid (NAA), was used to determine the rate of shoot proliferation. N-6-benzyladenine (BA) used at 0.5mg/l, was the most effective in initiating multiple shoot proliferation at the rate of 23 microshoots per shoot-tip explants after 40 days of culture. Shoot multiplication increased 1.2-fold in each successive subculture. Induction of rooting (98%) was achieved by transferring the shoots to the same basal medium containing 2 mg/l indole-3-butyric acid (IBA). Plantlets went through a hardening phase in a controlled growth chamber, prior to in vivo transfer. These results represented that possible application for the mass production of plantlets through in vitro culture system of Zanthoxylum piperitum DC.