• Journal of Climate Change Research
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• v.5 no.1
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• pp.13-19
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• 2014

In the past, Korea agro-climatic zone except Jeju-do was classified into nineteen based on rice culture by using air temperature, precipitation, and sunshine duration etc. during rice growing periods. It has been used for selecting safety zone of rice cultivation and countermeasures to meteorological disasters. In this study, the climatic variables such as air temperature, precipitation, and sunshine duration of twenty agro-climatic zones including Jeju-do were compared decennially (1970's, 1980's, 1990's, and 2000's). The meteorological data were obtained in Meteorological Information Portal Service System-Disaster Prevention, Korea Meteorological Administration. The temperature of 1970s, 1980s, 1990s, and 2000s were $12.0{\pm}0.14^{\circ}C$, $11.9{\pm}0.13^{\circ}C$, $12.2{\pm}0.14^{\circ}C$, and $12.6{\pm}0.13^{\circ}C$, respectively. The precipitation of 1970s, 1980s, 1990s, and 2000s were $1,270.3{\pm}20.05mm$, $1,343.0{\pm}26.01mm$, $1,350.6{\pm}27.13mm$, and $1,416.8{\pm}24.87mm$, respectively. And the sunshine duration of 1970s, 1980s, 1990s, and 2000s were $421.7{\pm}18.37hours$, $2,352.4{\pm}15.01hours$, $2,196.3{\pm}12.32hours$, and $2,146.8{\pm}15.37hours$, respectively. The temperature in Middle-Inland zone ($+1.2^{\circ}C$) and Eastern-Southern zone ($+1.1^{\circ}C$) remarkably increased. The temperature increased most in Taebak highly Cold zone ($+364mm$) and Taebak moderately Cold Zone ($+326mm$). The sunshine duration decreased most in Middle-Inland Zone (-995 hours). The temperature (F=2.708, df=3, p= 0.046) and precipitation (F=5.037, df=3, p=0.002) increased significantly among seasons while the sunshine duration decreased significantly(F=26.181, df=3, p<0.0001) among seasons. In further study, it will need to reclassify agro-climatic zone of rice and it will need to conduct studies on safe cropping season, growth and developing of rice, and cultivation management system etc. based on reclassified agro-climatic zone.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.249-260
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• 1995

6 Central commissary and 2 conventional school foodservice operations were assessed in terms of time-temperature relationship and microbiological quality, and monitoring control methods were identified through hazard analysis during the phases of prodution and distribution. 2 conventional schools from Seoul and 6 commissary schools from Kyungkido were participated in the survey. Meals produced in central commissary were distributed to satellites, therefore delivery practices of foods were identified as critical. Microbiological test results for commissary and conventional schools revealed that microbiological quality of foods was mainly related to time-temperature management, types of food, and equipment sanitation not to the foodservice system used. Time-temperature profiles at temperature danger zone (7.2-60$^{\circ}C$) observed were to be related to the following sanitary practices: cooked vegetables were held at temperature danger zone for relatively longer delayed time (15-38$^{\circ}C$: 15-226 min, 7-60$^{\circ}C$: 75-226 min), and same results were observed for deep-fat fried cutlets (15-38$^{\circ}C$: 15-151 min, 7-60$^{\circ}C$: 33-151 min). Menu items with various ingredients and frequent contacts with hands and equipments during the production flow were held at temperature danger zone for longer delaying time than other menu items with brief prodution stages. Based on hazard analysis critical control points, microbiological quality was collectively affected by time-temperature relationships, equipment sanitation, proper cooking methods, and sanitary management competencies of dietitians. Microbiological test results of working equipments and surface of dishes and trays showed that immediate action should be taken. Cutting boards used in central kitchen were also showed similar results of potential dager of cross-contamination. Effective sanitary control methods were urgently needed.

• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.89-97
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• 2018

The purpose of this reaserch is to analyze the charateristics of water quality in space through the operation of ARA River in Artificial Rivers of the Brackish Water Zone. The spatial distribution measured water temperature and salt levels for the surface, middle and deep layers by dividing the four areas of Incheon, Sicheon, Gyeyang and Gimpo. Water temperature did not vary much by water depth and branch, and its purpose is to maintain stable water environment through correlation analysis and operation. To examine the temporal and spatial distribution patterns of the Arachon, we measured DO on the Incheon branch, Sicheon, Gyeyang and Gimpo branch twice a month, and on the surface, the temperature level, The water temperature did not vary much by depth and location, and the water temperature in January and March tended to rise from Incheon to Gimpo, with the average difference of 1.1 degrees during the same period. The salinity difference between Incheon and Gimpo sites was 3.3 psu deep and 5.4 psu deep. In particular, floodgates from July to September are found to be less than 10psu overall, which is considered to be a gas due to the effects of floods and the inflow of Gulpo Stream. D.O. is located in some areas due to summer rains. The hypoxic layer has been identified.Analysis of seasonal data shows that water temperature and DO are strongly correlated in autumn. It was found that the water temperature and salt levels in the fall showed a weak correlation.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.283-296
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• 1992

The Keumryeong deposits is a low grade copper deposits in which copper minerals form disseminated grains and thin veinlets in felsic volcanics seem to be dacite. Alteration of the volcanics consists mainly pervasive propylitization and silicification. Potassic alteration characterized by biotite developed locally adjacent to southwestern contact of granodiorite body. Principal sulfide minerals in altered zone are mainly pyrite and lesser chalcopyrite. Chalcopyrite content in potassic zone is relatively higher than that of surrounding propylitized zone. Pyrite and chalcopyrite accompanies magnetite, molybdenite, sphalerite, pyrrhotite, arsenopyrite, pentlandite, marcasite, hematite, ilmenite, rutile, bismuthinite and native Bi as disseminations, veinlets and knots. Granodiorite body is propylitized and contains veinlets of pyrite, chalcopyrite and molybdenite. Fluid inclusions in sulfide-bearing quartz veinlets and quartz grains of felsic volcanics and granodiorite in altered zone consist of liquid-rich, vapor-rich, $CO_2-bearing$ and halite-bearing inclusions. These four types of inclusion intimately associated on a microscopic scale and indicate condensing or boiling of ore fluid during mineralization. Homogenization temperature of coexisting fluid inclusions are mostly in the range of 350 to $450^{\circ}C$. High salinity fluid contains 28.6 to 48.4 weight percent NaCI equivalent and moderate salinity fluid cotains 0.5 to 12.5 weight percent NaCl equivalent. Pressure estimated from $CO_2$ mole fraction of $CO_2-bearing$ inclusion range 160 to 375 bars. The Kigu copper deposits is a fissure filling copper vein developed 500 m south from the Keumryong deposits. Mineralogy and fluid inclusion data of the Kigu deposits are similar to that of the Keumryeong deposits. Homogenization temperature of fluid inclusions from the Kigu deposits are reasonable agreement with temperature estimated from sulfidation curve of cubanite-chalcopyrite-pyrite-pyrrhotite and pyrite-pyrrhotite mineral assemblages. Not only mineral occurrence and wall rock alteration in the Keumryeong deposits but also fluid inclusion data such as temperature, salinity, pressure and boiling evidences are similar to those of porphyry copper deposits.

• Journal of the Korean Society of Tobacco Science
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• v.12 no.2
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• pp.67-75
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• 1990

The pyrolytlc behavior of cocoa powder, a flavorant of tobacco smoking products, was examined by determining its pyrolyzate constituents. Cocoa powder was pyrolyzed of two cigarette smoking conditions'distillation-pyrolysis zone(35$0^{\circ}C$, 55$0^{\circ}C$) and high temperature zone($650^{\circ}C$, 85$0^{\circ}C$). Pyrolyzate was flushed from the tube by NB gas into CS2 trap in dry ice-acetone cooled bath and charcoal tube and its constituents were analyzed by GC/MS. As results, the major components of pyrolyzates were identified as hydrocarbon and phenolic compounds. In addition to these, aldehyde, ketone, pyrazin in very small amount. Component changes were observed with temperature increase; decane, styrene, tridecane, m-cresol,4-ethylphenol were increased while hexadecane, tetradecane were decreased. o-cresol and 2-ethylphenol were constant in amounts despite temperature change.

• Journal of Mechanical Science and Technology
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• v.15 no.4
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• pp.473-481
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• 2001

By depicting the transfer of heat and combustion reaction to take place within thin gas layers close to the propellant surface burning in a steady-state fashion, a mathematical equation has been deduced to describe the burning rate of solid propellant as a function of initial grain temperature and chamber pressure. It has been also assumed that chemical reaction could take place in premixing-diffusing zone but were carried out mainly in the reaction-flame zone. All these phenomena taken place in each zone of combustion have been assumed to be steady-state. In the present investigation, the equation, γ=$\kappa$$.$(1/R(T(sub)i+C))(sup)n$.$exp(-E(sub)a/R(T(sub)i+C))(P/z) is being presented and it is compared with experimental data. The proposed model has been tested and evaluated vis-a-vis strand burner data for three different propellants based on CTPB, and it has been found that the deviation of the computed burning rates from the measured rates ranged up to 2%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.422-425
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• 2005

This study predicts the heat-affected zone (HAZ) after electrical discharge machining. To predict HAZ, the temperature distribution is calculated using FEM. Heat flux is calculated from electrical energy, and it can be assumed Gaussian distribution. Plasma channel expands as time goes. Copper and NAK80 are used as the workpiece material. The depth of HAZ in simulation is determined by temperature distribution. The simulation results were compared with a developed actual single discharge crater. Through investigating the cross section of simulated & actual craters, the depth of HAZ in simulation and experiment are compared. Simulation model can predict the crater shape.

• Journal of Advanced Marine Engineering and Technology
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• v.13 no.4
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• pp.33-39
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• 1989

A turbulent premixed flames of layer formed between burned hot gas and unburned mixture were investigated by means of schlieren photograph with fluctuations of temperature and ion current. The combustion intensity between burned hot gas and shear layer was higher than the intensity between unburned mixture and shear layer. A wrinkled laminar flame and flamelet were appeared at downstream to exist and distributed reaction zone was at upstream as a result of analyzed probability density functions of temperature fluctuation. The initial combustion intensity of reaction zone of eddy between burned hot gas and shear layer was higher than that of final, flowing downstream, and vice versa between unburned mixture and shear layer.

• 한국연소학회:학술대회논문집
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• 1999.10a
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• pp.201-207
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• 1999

The combustion characteristics for the low NOx 50 kW-class gas turbine combustor have been experimentally investigated. In order to achieve the premixing and the lean burn combustion, the geometries of the primary zone including premixed chamber were modified from conventional combustor. The centerline profiles of CO and NO concentration, and temperature were measured for the premixed combustors with or without dilution holes in the liner. The effects of the pilot fuel injection rate and air dilution on flame stabilization and pollutant (CO, NO) emission are discussed in detail.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.309-317
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• 2018

In this study, a laser sheet technique and PLIF (Planar laser-induced fluorescence) are applied to a laboratory-scale pulverized coal burner of the open type, and the spatial relationship of the pulverized coal particle zone and the combustion reaction zone is examined by simultaneous measurement of Mie scattering and OH-LIF images. It is found that this technique can be used to investigate the spatial relationship of the combustion reaction zone and pulverized-coal particles in turbulent pulverized-coal flames without disturbing the combustion reaction field. In the upstream region, the combustion reaction occurs only in the periphery of the clusters where high-temperature burned gas of the methane pilot flame is entrained and oxygen supply is sufficient. In the downstream region, however, combustion reaction can be seen also within clusters of pulverized-coal particles, since the temperature of pulverized-coal particles rises, and the mixing with emitted volatile matter and ambient air is promoted.