• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.32-38
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• 2003

Staged combustion, such as air- and fuel-staging, is a relatively well-known technique fur reduction of NOx emission and used in combination with other techniques nowadays. However, the design variables are still selected depending upon operating conditions. There are many variables tested to investigate the NOx emission characteristics fur changing of fuel or air velocity, swirl intensity, and staging ratio of air and fuel in multi-staged burner. In air-staging case, the fuel-rich condition of the primary combustion zone is very helpful to reduce NOx emission and its range is known to be restricted by the increase of carbon monoxide. However, in many cases carbon monoxide level is not too high to be restricted operating condition. So we tried to expand the equivalence ratio range to the richer condition in the primary combustion zone and certificate the function of each burner component and its contribution to the overall NOx production.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1763-1773
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• 2014

It is known that mackerel and pork belly release a strong odor in the process of roasting. We evaluated a dilution factor of odor arising during roasting mackerel or pork belly and the relative odor strength using several cooking tools and analyzed compounds causing odors with gas chromatograph/mass detector. Roasting pans used were grill with lid, electric grill without lid and general roasting pan, and a grill with lid can attach the activated carbon charcoal deodorant at the inside of lid. And all electric grills have a drip tray under the heater. We investigated characteristics of odor emission depending on the presence of water and deodorants in these cooking tools. Study has shown that roasting mackerel produces approximately 36 time more odors than roasting pork belly, and the reduced odor emission when roast with water. And it shows the reduced deodorant effect when cooked with water after attaching activated carbon charcoal in the cooking pan. Major odor causing compounds arising when cooking mackerel and pork belly were aldehydes with high boiling point such as octyl aldehyde with a low odor threshold value.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.3
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• pp.208-213
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• 2002

We present the temperature and excitation power density dependence of the photoluminescence from carbon-doped GaAs epilayers grown on GaAs (311)A substrate by atmospheric pressure metalorganic chemical vapor deposition. The measured temperature dependence of the PL peak energy is well expressed by an empirical formula proposed by Varshni. The thermal quenching mechanism of the intensity of 16 K luminescence peak at 1.480 eV is described with the dominant activation energy of 27$\pm$2 meV. The activation energy shows an evidence that the emission band involves the carbon acceptor in the recombination process.

• Analytical Science and Technology
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• v.17 no.5
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• pp.416-422
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• 2004

Time-resolved laser induced breakdown spectroscopy (TRELIBS) has been developed and applied to the qualitative analysis of the component materials of nuclear power plant. The alloy samples used in this work were carbon steels (A106 Gr. B; A336 P11; A335 P22), stainless steels (type 304; type 316) and inconel alloys (Inconel 600; Inconel 690; Inconel 800). Carbon steels can be individually distinguished by the intensity ratio of chromium to iron and molybdenum to iron emission lines observed at the wavelength raging from 485 to 575 nm. Type 316 stainless steel can be easily differentiated from type 304 by identification of the molybdenum emission lines at an emission wavelength ranging from 485 to 575 nm: type 304 does not give any molybdenum emission lines, but type 316 does. The inconel alloys can be individually distinguished by the intensity ratio of Cr/Fe and Ni/Fe emission lines at the wavelength raging from 420 to 510 nm. TRELIBS has been proved to be a powerful analytical technique for direct analysis of alloys due to its non-destructivity and simplicity.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.297-299
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• 2014

Petroleum coke has high heating value and low price. Due to the steadily increasing demand for heavy oil processing, the production volume of petroleum coke tends to be expanded. The high availability and low price of petroleum coke have been strongly considered as candidate fuel for power generation facilities. However the high carbon content, high sulfur content and nitrogen content of petroleum fuel are known to produce relatively large quantity of CO2, high NOx and SO2 emission. In this work, a series of numerical simulations have been carried out in order to investigate the effects of swirl flow intensity on combustion furnace, which is most important operating condition. Results show that the temperature distribution was spatially uniform at about 1600K but high temperature region are located quite differently depending on swirl number. In addition, numerical temperature data was compared with experimental temperature data and its temperature difference shows less than 10%. On the other hand, discrepancy between numerical and experimental emission data were slightly large with necessities of improved emission model.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.162-169
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• 2012

Our country set the mid-term reduction goal of greenhouse gases up to 2020 in accordance with Bali roadmap agreed in 2007 through the negotiation with UNFCCC in 2009 and specified the proper goal as by the Basic Act on Green Growth that went into effect at April, 2010. First of all the enlargement of green building construction has been suggested as a worldwide strategy to achieve the green house gas reduction. Building area is one of most important sectors for the countermeasure of climate change agreement and the achievement of national green house gas reduction goal and the need to reduce its green house gases has been increased accordingly. The objective of the study is to examine the status and characterization of mass energy consumption local governmental buildings' green house gas emissions depending on usage (hotel, school, apartment, hospital) through the green house gas emission source unit analysis. The result indicated that the energy source unit was proportional to green house gas source unit and hotel showed the highest green house gas emission source unit per open area of construction unit, followed by hospital, apartment, and then school. In case of apartment, green house gas emission source unit per open area of construction unit decreased as year went on. Meanwhile school building showed a striking increase in the annual energy source unit.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.89-92
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• 2011

Hydrogenated amorphous carbon (a-C:H) films were deposited by plasma enhanced chemical vapor deposition on silicon substrates. a-C:H thin film was irradiated to a typical He-Cd laser to study its emitting properties. The photoluminescence (PL) intensity during the irradiation achieved a maximum value when 2,000 seconds elapsed. Fourier transform infrared measurement revealed a-C:H thin film suffered transformation from a polymer-like to graphite-like phase during laser irradiation. Thermal annealing was done at various temperatures, ranging from room temperature to $400^{\circ}C$ in the atmosphere, to investigate structural changes in a-C:H film by heat generation during the emission. PL intensity of a-C:H thin film increased 1.5 times without apparent structural change, as annealing temperature increased up to $200^{\circ}C$. However, a-C:H film above $200^{\circ}C$ exhibited significant decrease of PL accompanying dehydrogenation. This led to a red shift of the PL peak.

• Proceedings of the Korean Vacuum Society Conference
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• 1994.06a
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• pp.92-92
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• 1994

Relative intensities of photons emitted from tilted carbon foils have been measured in the wavelength region 300800 nm by 0,6-2,4 MeV $H^{+}\;and\;He^{+}$ ion impacts, Ions were directed onto target surfaces at tilt angles with respect to the sllrface normal, Experimental results support the model that the observed continuum radiation is emitted from the exited carbon foil itself. At each incident projectile energy, the photon intensities of continuum spectra for tilted carbon foi Is were compatred to the stoppi ng powers of carbon for $H^{+}\;and\;He^{+}$ ions, It was found that the photon emission intensity for $H^{+}$ ion is linearly proportional to the stopping power, whereas that for $He^{+}$ ions is proportional to a higher power of the stopping power, and that this tendency increases wi th decreasing velocity of the projectiIes[1, 2].[1, 2].

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.272-277
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• 2009

Three dimensional numerical analysis for the coal fired boiler has been performed to investigate the effect of yaw angle variation of the secondary air nozzles on the combustion characteristics and NOx emission. It was found that the prediction gives a good agreement with plant data. The increase in yaw angle up to $20^{\circ}$ have results in the decrease in NOx emission at furnace exit and recirculation flow intensity, together with the increase of unburned carbon in ash. It also has been recognized the remarkably change in configuration of fire ball with increase in yaw angle. The results from this study would be valuable in the case of the combustion modification of the corner firing coal-fired utility boiler.

• Journal of Korean Society on Water Environment
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• v.37 no.5
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• pp.344-354
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• 2021

Optical methods such as UV and fluorescence spectrophotometers can be applied not only in the qualitative analysis of dissolved organic matter (DOM), but also in real-time quantitative DOM monitoring for wastewater and natural water. In this study, we measure the UV₂₅₄ and fluorescence excitation emission spectra for a sewage treatment plant influent and effluent, and river water before and after sewage effluent flows into the river to examine the composition and origin of DOM. In addition, a correlation analysis between quantified DOM characteristics and dissolved organic carbon (DOC) was conducted. Based on the fluorescence excitation emission spectra analysis, it was confirmed that the protein-type tryptophan-like DOM was the dominant substance in the influent, and that the organic matter exhibited relatively more humic properties after biological treatment. However, DOM in river water showed the fluorescence characteristics of terrestrial humic-like and algal tyrosine-like (protein-like) organic matter. In addition, a correlation analysis was conducted between the DOC and optical indices such as UV₂₅₄, the fluorescence intensity of protein-like and humic-like organic matter, then DOC prediction models were suggested for wastewater and river monitoring during non-rainfall and rainfall events. This study provides basic information that can improve the understanding of the contribution of DOC concentration by DOM components, and can be used for organic carbon concentration management in wastewater and natural water.