• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.605-608
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• 2007

• Defense and Technology
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• no.3 s.229
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• pp.18-21
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• 1998

• 대한치과교정학회:학술대회논문집
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• 2003.10a
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• pp.106.1-106.1
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• 2003

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.10
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• pp.1178-1183
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• 2004

The purpose of this study was to investigate the influence of compression ratio on engine performance in a LPG(Liquefied Petroleum Gas) engine converted from a diesel engine. In ordor to determine the ideal compression ratio, a variable compression ratio 4-cylinder engine was developed. Retrofitting a diesel engine into a LPG engine is technically very complicated compared to a gasoline to LPG conversion. The cylinder head and the piston crown were modified to bum LPG in the engine. Compression ratios were increased from 8 to 10 in an increment of 0.5, the ignition timing was controlled to be at MBT(Minimum Spark Advance for Best Torque) for each case.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.241-248
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• 1999

The photocatalytic decolorization and photodegradation of wastewater contamininated with dyes such as methyleneblue tetrahydrate(MBT), methyl orange(MO), phenol red(PR) and the mixed dyes have been studied using a batch reactor in the presence of aerotropic and titania. Degussa P25 titanium oxide was used as the photocatalyst and proved to be effective for the dyes-degradation when irradiated with UV-light source emitting the wavelength of 253.7 nm in the presence of air. In addition to removing the color from the wastewater, the photocatalytic reaction simultaneously reduced the COD and optical density which suggests that the dissolved organic compounds have been photooxidized. The reaction rate of disappearance of the dyes were measured as a function of the irradiation times. The photooxidative procedure of the aquatic solution have the first order reaction-kinetics. The rate constants were increased in the order of PR < MBT < $gL^{-1}-TiO_2$ powder were irradiated with the UV -light source.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.2
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• pp.121-132
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• 1982

Engine torque, specific fuel consumption and MBT spark advance of a domestic automotive engine fueled with methanal-gasoline blends or straight methanal were studied under steady state condition and compared to those obtained with gasoline. The effects of adding methanal to gasoline on engine performance were studied with or without any carburetor modification. At first, the engine was operated without any modification. Next, the diameters of metering orifices in carburetor were modified to give the same excess air factor regardless of fuel type under each fixed engine operating condition. Finally, the diameters of metering orifices in carburetor were modified to give the same excess air factor for 15% mixture of methanal in gasoline by volume as for gasoline with standard metering orifices in carburetor. The effects of adding methanal to gasoline on engine torque, specific energy consumption and MBT spark advance can be explained on the basis of change in stoichiometry caused by the addition of methanal to gasoline.

• Journal of Energy Engineering
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• v.15 no.3 s.47
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• pp.139-145
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• 2006

The purpose of this study is to obtain low-emission and high-efficiency in LPG engine with hydrogen enrichment. The objective of this paper is to clarify the effects of hydrogen enrichment in LPG fuelled engine on exhaust emission, thermal efficiency and performance. The compression ratio of 8 was selected to avoid abnormal combustion. To maintain equal heating value of fuel blend, the amount of LPG was decreased as hydrogen was gradually added. The relative air-fuel ratio was increased from 0.8 to 1.3, and the ignition timing was controlled to be at MBT (minimum spark advance for best torque)

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.6
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• pp.14-20
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• 2008

A battle management system should be introduced to improve mission success capabilities and accommodate integrated combat capabilities through increasing SA(Situation Awareness), or spatiotemporal synchronization of military operation in battle field environment. Conventional Korean Main Battle Tanks(Korean MBTs), which have been operated without digital network, were developed for 1980s. Korean new MBTs, which are mounted the battle management system, will be fielded soon. Therefore, old Korean MBT is needed to improve performances for co-operation with new one. This paper is reviewed each improved MBTs of world countries and domestic maintenance facilities. And this study suggests some processing methods which might be applicable to improve information network performance of old Korean MBTs.

• Journal of Power System Engineering
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• v.12 no.4
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• pp.12-17
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• 2008

The purpose of this study is to analyse and compare the fuel combustion characteristics between LPG and gasoline on SI engine. Pressures of combustion chamber were measured on the state that engine speed was 2000rpm and BMEP was 2.0bar And we measured pressures of combustion chamber regarding variation of the MBT We could know that the combustion pressure of LPG fuel use engine is appeared lower than that of gasoline fuel use engine. At the lean mixture ratio area we could blow that Ignition timings are pulled very forward, and ignition timing of LPG fuel is advanced to $5\sim12^{\circ}$ CA than gasoline fuel. We learned that the value of coefficient of variation of LPG fuel is higher than gasoline fuel.

• IE interfaces
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• v.18 no.3
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• pp.350-360
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• 2005

This paper considers a strategy for planning of rework in semiconductor monitoring burn-in test process. The equipment error in monitoring burn-in test process generates many defects. These defects are transformed into good products by rework process, i.e. retest. Rework has the advantage of saving production costs. But rework increases holding costs and incurs rework costs. In monitoring burn-in test process, rework depends on operator's experience with no pre-defined specification. In practice, a number of rework activities are performed with respect to the product importance and inventory quantity. Moreover, disregard for order jobs schedule have caused due date penalties. So a strategy for planning of rework by which order jobs schedule are not affected is suggested. Futhermore, production costs, rework costs and inventory costs for planning of rework are considered.