• Journal of Environmental Health Sciences
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• v.22 no.4
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• pp.49-54
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• 1996

The anaerobic landfill leachate treatment can surmount dilution problem of high concentration landfill leachate, collect methane gas as byproduct, and treat low phosphate concentration leachate because of low nutrient salt requirement. The problems of conventional anaerobic treatment that are requirement of large reactor because of low microbial growth rate(HRT=20-30 days) and low volumetric loading rate(VLR=0.5-2.0 kg $COD/m^3\cdot day$) are able to surmount by introduction of high rate anaerobic treatment. In this study, the upflow blanket filter(UBF) which is high rate anaerobic process was applyed to the landfill leachate treatment. The acceptable volumetric loading rate and HRT were 18.23 kg $SCOD/m^3\cdot day$ and 13 hrs. SCOD removal rate was over 90% at VLR 18.23 kg $SCOD/m^3\cdot day$. The methane gas yield was $0.15 lCH_4/g$ SCOD added(at STP) at VLR 18.23 kg $SCOD/m^3\cdot day$. The solids accumulation yield was 0.40 g VSS/g COD removed.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.5
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• pp.58-64
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• 2006

Homogeneous charge compression ignition(HCCI) combustion is an advanced technique for reducing the hazardous nitrogen oxide(NOx) and particulate matter(PM) in a diesel engine. NOx could be reduced by achieving lean homogeneous mixture resulting in combustion temperature. PM could be also reduced by eliminating fuel-rich zones which exist in conventional diesel combustion. However previous researches have reported that power-output of HCCI engine is limited by the high intensive knock and misfiring. In an attempt to extend the upper load limit for HCCI operation, supercharging in combination with Exhaust Gas Recirculation(EGR) has been applied: supercharging to increase the power density and EGR to control the combustion phase. The test was performed in a single cylinder engine operated at 1200 rpm. Boost pressures of 1.1 and 1.2 bar were applied. High EGR rates up to 45% were supplied. Most of fuel was injected at early timing to make homogeneous mixture. Small amount of fuel injection was followed near TDC to assist ignition. Results showed increasing boost pressure resulted in much higher power-output. Optimal EGR rate influenced by longer ignition delay and charge dilution simultaneously was observed.

• Natural Product Sciences
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• v.10 no.6
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• pp.325-329
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• 2004

The composition of essential oil from O. javanica was analyzed by gas chromatography-mass spectrometry. Using the broth dilution method and disk diffusion test, anti-microbial activities of the oil fraction and its main components were evaluated against various antibiotic-susceptible and resistant strains of pathogenic microorganisms. As a result of GC-MS analysis, 57 compounds, including ${\alpha}-terpinolene$ (28.1%), dl-limonene (16.0%), ${\gamma}-terpinene$ (10.3%), ${\beta}-pinene$ (9.7%) and ${\alpha}-pinene$ (6.0%) were identified in the essential oil fraction. The essential oil fraction of O. javanica and its main components exhibited significant inhibitory activities, particularly against Candida albicans (antibiotic-susceptible strains) and Streptococcus pneumoniae (antibiotic- susceptible and resistant strains). The main components of the O. javanica oil fraction displayed different patterns of activity against the three tested Candida species as exemplified by the differential minimum inhibiting concentration (MIC) values. The disk diffusion test showed that the activities were dose dependent.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.197-200
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• 2001

Novel Enhanced Inductively Coupled Plasma is applied to etch $SiO_2$. Effect of $O_2$ or Ar addition to $C_{4}F_{8}$ gas is monitored by Optical Emission Spectroscopy and Quadrupole Mass Spectrometer. It is fund that Ar or $O_2$ dilution to $C_{4}F_{8}$ increases F emission intensity and decreases $CF_2$ intensity. However, the ac frequency to the Helmholtz coil decreases the F intensity and thus increases $CF_2$/F ratio. By adjusting the ac frequency, the optimum etch rate and PR to $SiO_2$ selectivity can be obtained in E-lCP.

• Journal of Korean Society of Water and Wastewater
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• v.7 no.1
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• pp.5-12
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• 1993

The objectives of this paper are to present data to illustrate how an advanced digestion process, two-phase digestion, can provide superior performance in terms of waste stabilization efficiency and net energy recovery. As the result, it is possible to separate enrichment cultures of acidogenic and methanogenic organisms in isolated environments by kinetic control involving manipulation of dilution rates. In single-phase digestion process, HRT and COD loading for effective operation were 14.29 days and 2.33kg $COD/m^3$ day, but two-phase digestion may be conducted efficiently at 7 days of HRT and 5.71kg $COD/m^3$ day of loading. Data from this studies showed that the two-phase process is better than single-phase digestion under all test conditions when compared on the bases of gas yield and production rate, reductions of COD and VS, buffer capacity, and unconverted volatile acids in the effluent.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2001.05a
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• pp.31-34
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• 2001

Laser cladding Processing allows rapid transfer of heat to the material being minimum conduction into base metal. The effects of CO$_2$ laser cladding with high powder were investigated. High viscosity bronze powder consists of bronze powder used at a high temperature. The material has a high viscosity So that it can be substrate. Therefore. Laser cladding can be processed on a curved or slope surface. CO$_2$ laser cladding was designed It consists of the high viscosity bronze powder the shielding gas system and the preheating system The high viscosity powder properly at 0.3g/s and 0.50g/s. Because of the metallic bond between bronze per the hardness of dilution layer was suddenly increased. Experimental as results viscosity mixed powder can be a useful cladding material.

• Journal of ILASS-Korea
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• v.22 no.4
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• pp.190-196
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• 2017

The aim of this work is to investigate the combustion and exhaust emission characteristics of low-temperature combustion (LTC) at various EGR test conditions using a single cylinder common-rail diesel engine. In high EGR rate combustion mode with DME fuel, 30% (${\Phi}=0.61$) and 50% (${\Phi}=0.86$) of EGR were respectively examined, and then the combustion, exhaust emissions, nano-particle characteristics of each cases were measured. From these results, it revealed that The ignition delay and combustion duration are prolonged as the increase of EGR rate. In addition, at an advanced injection timing (BTDC $30^{\circ}$), ignition delays were fairly increased because the dilution effect of EGR and also low charge in-cylinder temperature created a lean mixture, thus decreased the peak release rate.

• YAKHAK HOEJI
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• v.54 no.2
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• pp.122-125
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• 2010

The essential oil fraction was extracted from the aerial parts of the plant by steam distillation method and its composition was analyzed by GC-MS (gas chromatography-mass spectrometry) which led to the identification of 43 compounds. Dehydroelsholtzia ketone (56.81%) and elsholtzia ketone (30.05%) were identified as the predominant components of this oil. The antibacterial activities of the essential oil fraction were assessed by micro-dilution tests against antibioticsusceptible and -resistant strains of Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enteritidis, and S. typhimurium. The oil inhibited most of the tested strains significantly resulting MICs (minimum inhibiting concentrations) between 2 mg/ml and >16 mg/ml. In most cases of this study Streptococcus pneumoniae and Staphylococcus aureus showed higher sensitivity to this oil than Salmonella strains.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.152-157
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• 2006

The air pollutant emission from the railroad diesel locomotive is still a significant environmental concern in many countries including Korea and Unites States. The emission characteristics of the railroad diesel locomotive were extensively studied in this study. Particulate matter (PM) and nitrogen oxides ($NO_x$) emitted from a large locomotive engine (2-cycle, 16-cylinder, and 3,000-horsepower) under various engine-rating conditions was analyzed with a scanning mobility particle sizer and a gas stack sampler by using a dilution tunnel. We could gain the emission values of 2.1 g/horsepower-hour for PM and 42.7 g/horsepower-hour for $NO_x$. We proposed the emission reduction goal of the railroad diesel locomotive for Korea in comparison with the regulation of United States.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.58.1-58.1
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• 2011

We present elemental abundances of 95 blue compact dwarf galaxies (BCDs) at z=0.2~0.35 using the Sloan Digital Sky Survey (SDSS) DR7. We derived element abundances using Te method. We found that nitrogen abundance of merging BCDs are more enriched than normal BCDs by fast rotating young massive star. On the other hand, neon and oxygen abundances for merging BCDs are slightly lower than the normal BCDs. This might be result from the dilution by metal-poor gas infall during the interaction. This means that merging BCDs undergone star formation event for a long time than normal BCDs and we trying to explain using STARLIGHT code and various star formation rates (SFRs) ratios. At a result, merging BCDs have older stellar population (>10 Myr) more than normal BCDs and have clear distinction in elements abundances versus Ha/UV diagram. We also discuss the characteristics of post merger candidate using FUV to NUV ratios.