• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.1
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• pp.15-24
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• 2015

$CH_4$ is a trace gas and one of the key greenhouse gases, which requires continuous and systematic monitoring. The application of eddy covariance technique for $CH_4$ flux measurement requires a fast-response, laser-based spectroscopy. The eddy covariance measurements have been used to monitor $CO_2$ fluxes and their data processing procedures have been standardized and well documented. However, such processes for $CH_4$ fluxes are still lacking. In this note, we report the first measurement of $CH_4$ flux in a rice paddy by employing the eddy covariance technique with a recently commercialized wavelength modulation spectroscopy. $CH_4$ fluxes were measured for five consecutive days before and after the rice transplanting at the Gimje flux monitoring site in 2012. The commercially available $EddyPro^{TM}$ program was used to process these data, following the KoFlux protocol for data-processing. In this process, we quantified and documented the effects of three key corrections: (1) frequency response correction, (2) air density correction, and (3) spectroscopic correction. The effects of these corrections were different between daytime and nighttime, and their magnitudes were greater with larger $CH_4$ fluxes. Overall, the magnitude of $CH_4$ flux increased on average by 20-25% after the corrections. The National Center for AgroMeteorology (www.ncam.kr) will soon release an updated KoFlux program to public users, which includes the spectroscopic correction and the gap-filling of $CH_4$ flux.

• The Journal of the Petrological Society of Korea
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• v.13 no.4
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• pp.179-190
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• 2004

Precambrian metamorphic rocks of Yeongyang-Uljin area, which is located in the eastern part of Sobaegsan Massif, Korea, are composed of Pyeonghae, Giseong, Wonnam Formations and Hada leuco granite gneisses. These show a zonal distribution of WNW-ESE trend, and are intruded by Mesozoic igneous rocks and are unconformably overlain by Mesozoic sedimentary rocks. This study clarifies the deformation history of Precambrian metamorphic rocks after the formation of gneissosity or schistosity on the basis of the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area experienced at least four phases of deformation i.e. ductile shear deformation, one deformation before that, at least two deformations after that. (1) The first phase of deformation formed regional foliations and WNW-trending isoclinal folds with subhorizontal axes and steep axial planes dipping to the north. (2) The second phase of deformation occurred by dextral ductile shear deformation of top-to-the east movement, forming stretching lineations of E-W trend, S-C mylonitic structure foliations, and Z-shaped asymmetric folds. (3) The third phase deformation formed I-W trending open- or kink-type recumbent folds with subhorizontal axes and gently dipping axial planes. (4) The fourth phase deformation took place under compression of NNW-SSE direction, forming ENE-WSW trending symmetric open upright folds and asymmetric conjugate kink folds with subhorizontal axes, and conjugate faults thrusting to the both NNW and SSE with drag folds related to it. These four phases of deformation are closely connected with the orientation of regional foliation in the Yeongyang-Uljin area. 1st deformation produced regional foliation striking WNW and steeply dipping to the north, 2nd deformation locally change the strike of regional foliation into N-S direction, and 3rd and 4th deformations locally change dip-angle and dip-direction of regional foliation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.969-977
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• 2001

The purpose of this study was to investigate disinfection state and effective factors of utensils and equipments used to foodservice of elementary schools in Busan area, The questionnaire which was administered to 160 dietitians was used in this study as a survey method. The results were as follows. The disinfection method of tray was mainly used by electric gas. Table and other products of stainless steel sanitized by sodium hypochlorite and hot water, but above 51% of slicer. grinder and peeler were not sanitized after used. The products of wood and plastic also used mainly sodium hypochlorite and hot water as sanitizers. In disinfection time, knife, wood spoon and plastic products should be sanitized on demand, but 30.9~53.5% of this utensils except rice scoop were sanitized on demand that showed deficiency of cognition for sanitation. The disinfection of most of utensils and equipments was conducted every day, but food case, slicer, peeler, grinder and wood spoon showed lower disinfection frequency than other products, The method of disinfection was related to dietitians age and career number of total serving, duration of foodservice and serving place, The disinfection time was also affected by dietitians age and educational level, and serving place. The disinfection frequency was affected by number of employee, number of total serving and duration of foodservice. Therefore based on the results of this study, it should be given to the microbiological study on disinfection method of utensils such as slicer, grinder, peeler, large spoon, plastic prouducts and the dietitians sanitation training also should be conducted continuously.

• Geophysics and Geophysical Exploration
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• v.8 no.1
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• pp.67-72
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• 2005

To investigate the feasibility of a new concept of storing Liquefied Natural Gas (LNG) in a lined hard rock cavern, and to develop essential technologies for constructing underground LNG storage facilities, a small pilot plant storing liquid nitrogen (LN2) has been constructed at the Korea Institute of Geoscience and Mineral Resources (KIGAM). The LN2 stored in the cavern will subject the host rock around the cavern to very low temperatures, which is expected to cause the development of an ice ring and the change of ground condition around the storage cavern. To investigate and monitor changes in ground conditions at this pilot plant site, geophysical, hydrogeological, and rock mechanical investigations were carried out. In particular, geophysical methods including borehole radar and three-dimensional (3D) resistivity surveys were used to identify and monitor the development of an ice ring, and other possible changes in ground conditions resulting from the very low temperature of LN2 in the storage tank. We acquired 3D resistivity data before and after storing the LN2, and the results were compared. From the 3D images obtained during the three phases of the resistivity monitoring survey, we delineated zones of distinct resistivity changes that are closely related to the storage of LN2. In these results, we observed a decrease in resistivity at the eastern part of the storage cavern. Comparing the hydrogeological data and Joint patterns around the storage cavern, we interpret this change in resistivity to result from changes in the groundwater flow pattern. Freezing of the host rock by the very low temperature of LN2 causes a drastic change in the hydrogeological conditions and groundwater flow patterns in this pilot plant.

• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.379-388
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• 1994

Background : In sleep apnea syndrome, arterial oxygen saturation($SaO_2$) decreases at a variable rate and to a variable degree for a given apneic period from patient to patient, and various kinds of cardiac arrythmia are known to occur. Factors supposed to affect arterial oxygen desaturation during apnea are duration of apnea, lung voulume at which apnea occurs, and oxygen consumption rate of the subject. The lung serves as preferential oxygen source during apnea, and there have been many reports related with the influence of lung volume on $SaO_2$ during apnea, but there are few, if any, studies about the influence of oxygen consumption rate of an individual on $SaO_2$ during breath holding or about the profile of arterial oxygen resaturation after breathing resumed. Methods : To investigate the changes of $SaO_2$ and heart rate(HR) during breath holding(BH) and rebreathing(RB) and to evaluate the physiologic factors responsible for the changes, lung volume measurements, and arterial blood gas analyses were performed in 17 healthy subjects. Nasal airflow by thermistor, $SaO_2$ by pulse oxymeter and ECG tracing were recorded on Polygraph(TA 4000, Gould, U.S.A.) during voluntary BH & RB at total lung capacity(TLC), at functional residual capacity(FRC) and at residual volume(RV), respectively, for the study subjects. Each subject's basal metabolic rate(BMR) was assumed on Harris-Benedict equation. Results: The time needed for $SaO_2$ to drop 2% from the basal level during breath holding(T2%) were $70.1{\pm}14.2$ sec(mean${\pm}$standard deviation) at TLC, $44.0{\pm}11.6$ sec at FRC, and $33.2{\pm}11.1$ sec at RV(TLC vs. FRC, p<0.05; FRC vs. RV, p<0.05). On rebreathing after $SaO_2$ decreased 2%, further decrement in $SaO_2$ was observed and it was significantly greater at RV($4.3{\pm}2.1%$) than at TLC($1.4{\pm}1.0%$)(p<0.05) or at FRC($1.9{\pm}1.4%$)(p<0.05). The time required for $SaO_2$ to return to the basal level after RB(Tr) at TLC was not significantly different from those at FRC or at RV. T2% had no significant correlation either with lung volumes or with BMR respectively. On the other hand, T2% had significant correlation with TLC/BMR(r=0.693, p<0.01) and FRC/BMR (r=0.615, p<0.025) but not with RV/BMR(r=0.227, p>0.05). The differences between maximal and minimal HR(${\Delta}HR$) during the BH-RB manuever were $27.5{\pm}9.2/min$ at TLC, $26.4{\pm}14.0/min$ at RV, and $19.1{\pm}6.0/min$ at FRC which was significantly smaller than those at TLC(p<0.05) or at RV(p<0.05). The mean difference of 5 p-p intervals before and after RB were $0.8{\pm}0.10$ sec and $0.72{\pm}0.09$ sec at TLC(p<0.001), $0.82{\pm}0.11$ sec and $0.73{\pm}0.09$ sec at FRC(p<0.025), and $0.77{\pm}0.09$ sec and $0.72{\pm}0.09$ sec at RV(p<0.05). Conclusion Healthy subjects showed arterial desaturation of various rates and extent during breath holding at different lung volumes. When breath held at lung volume greater than FRC, the rate of arterial desaturation significantly correlated with lung volume/basal metabolic rate, but when breath held at RV, the rate of arterial desaturation did not correlate linearly with RV/BMR. Sinus arrythmias occurred during breath holding and rebreathing manuever irrespective of the size of the lung volume at which breath holding started, and the amount of change was smallest when breath held at FRC and the change in vagal tone induced by alteration in respiratory movement might be the major responsible factor for the sinus arrythmia.