• Journal of Wetlands Research
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• v.12 no.1
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• pp.95-103
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• 2010

Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. However, it needs lots of time and money to get the discharge data. So discharge rating curve is usually used in converting discharge data. Therefore reliability of discharge rating curve absolutely depends on quality of discharge data. Many engineers who study hydrologic engineering make high quality discharge data to develop reliable discharge rating curve. And they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and experimental research data from measurement are not enough. In this paper, constant discharge flowed through standard concrete channel, and the velocity is measured using various flow meters. Also Discharge is calculated by measured data to compare and analyze. The equipment for the experiment is Price AA(USGS Type AA Current meter), flow meter, ADC, C2 small current meter, flow tracker, Electromagnetic current meter. The discharge got form various flow meters which are widely used for discharge measurement. The various depths of water were examined and compared such as 0.30 m, 0.35 m, 0.40 m, 0.45 m, 0.50 m, 0.55 m. The experiment progresses a round-measurement on 6-case. Wading measurement(one point method : the 60 % height in surface of the water) was applied to improve creditability and accuracy among measurement methods. USGS Type AA current Meter, Flow Meter, ADC, C2 Small Current meter got the certificate of quality guaranteed. So the results of experiment were used to compare discharge. The Results showed the difference based on USGS Type AA current Meter at average discharge and velocity. Electromagnetic current meter made differences over $\pm$ 10 % and Flow Meter made differences under $\pm$ 10 %. Also ADC, Flow Meter, C2 Small Current meter made differences under $\pm$ 5 %.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.660-667
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• 2018

This study examined the optimal manufacturing conditions of RDF using heat-dried sludge from sewage treatment plant in Cheonan with the oil-drying method. The amounts of oil evaporation and oil drying of the heat-dried sludge were measured at different temperatures to evaluate the value of the product. The performance of the product was then measured using a calorimeter and TGA. In addition, the concentration of odor, NH3, H2S, and TVOC during drying was determined using a portable odor-meter. Ingredient analysis was performed by EDS. Considering mass-production, the oil to heat-dried sludge weight ratio was fixed to 4:1. At $130^{\circ}C$, only physical mixing occurred after the instantaneous drying of internal water. Considering the eco-friendly aspects, there was no significant difference in the drying efficiency between $160^{\circ}C$ and $190^{\circ}C$. Therefore, the optimal conditions were a drying temperature of $160^{\circ}C$ within 5 minutes. Finally, the RDF manufactured in this study and fuel used in the thermal power plants were compared. The calorific value was 4,449kcal/kg, the water content was 2% and the ash content was 34%, which is higher than the fuel of thermal power plants. Therefore, it is believed that coal energy as well as wood pellets can be replaced.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.228-232
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• 2018

Process-based crop models have been used to assess the impact of climate change on crop production. These models are implemented in procedural or object oriented computer programming languages including FORTRAN, C++, Delphi, Java, which have a stiff learning curve. The requirement for a high level of computer programming is one of barriers for efforts to develop and improve crop models based on biophysical process. In this study, we attempted to develop a Chinese cabbage model using Microsoft Excel with Visual Basic for Application (VBA), which would be easy enough for most agricultural scientists to develop a simple model for crop growth simulation. Results from Soil-Plant-Atmosphere-Research (SPAR) experiments under six temperature conditions were used to determine parameters of the Chinese cabbage model. During a plant growing season in SPAR chambers, numbers of leaves, leaf areas, growth rate of plants were measured six times. Leaf photosynthesis was also measured using LI-6400 Potable Photosynthesis System. Farquhar, von Caemmerer, and Berry (FvCB) model was used to simulate a leaf-level photosynthesis process. A sun/shade model was used to scale up to canopy-level photosynthesis. An Excel add-in, which is a small VBA program to assist crop modeling, was used to implement a Chinese cabbage model under the environment of Excel organizing all of equations into a single set of crop model. The model was able to simulate hourly changes in photosynthesis, growth rate, and other physiological variables using meteorological input data. Estimates and measurements of dry weight obtained from six SPAR chambers were linearly related ($R^2=0.985$). This result indicated that the Excel/VBA can be widely used for many crop scientists to develop crop models.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.389-394
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• 2014

This study was conducted to find out the soil $CO_2$ emission characteristic due to rain fall pattern and intensity changes. Using Automatic Opening and Closing Chambers (AOCCs), we have measured annual soil respiration changes in Pinus koraiensis plantation at Seoul National University experimental forest in Mt. Taehwa. In addition, we have monitored heterotrophic respiration at trenching sites ($4{\times}6m$). Based on the one year data of soil respiration and heterotrophic respiration, we observed that 24% of soil respiration was derived from root respiration. During the rainy season (end of July to September), soil respiration at trenching site and trenching with rainfall interception site were measure during portable soil respiration analyzer (GMP343, Vaisala, Helsinki, Finland). Surprisingly, even after days of continuous heavy rain, soil water content did not exceed 20%. Based on this observation, we suggest that the maximum water holding capacity is about 20%, and relatively lower soil water contents during the dry season affect the vital degree of trees and soil microbe. As for soil respiration under different rain intensity, it was increased about 14.4% under 10 mm precipitation. But the high-intensity rain condition, such as more than 10 mm precipitation, caused the decrease of soil respiration up to 25.5%. Taken together, this study suggests that the pattern of soil respiration can be regulated by not only soil temperature but also due to the rain fall intensity.

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.247-252
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• 2014

Gagok Mine, which is skarn deposits, includes sulfide minerals such as sphalerite, galena, chalcopyrite, and pyrrhotite. To explore these minerals, spectral induced polarization (SIP) is relatively effective compared to other geophysical exploration methods because there is a strong IP effect caused by electrode polarization. In the SIP, the chargeability related to sulfide mineral contents and the time constant related to the grain size of the minerals are obtained. For this reason, we aim to compare difference in the mineralized characteristics between two orebodies in the Gagok Mine by using the chargeability and the time constant. For this study, we sampled ores from the south of Wolgok orebody and the north of Sungok orebody. In order to recognize the mineralization characteristics, the metal content of the samples was measured by a potable XRF and the SIP data of the samples were acquired by using a laboratory SIP measurement system. As a result, the metals in the samples such as Pb, Zn, Cu, and Fe were detected by the portable XRF measurement. In particular, the Fe and Zn contents were far higher than the other metals. The Fe and the Zn were caused by the sphalerite and the pyrrhotite through microscopy. The Wolgok orebody had higher sulfide mineral contents than the Sungok orebody and the result corresponded with the chargeability result. However, we considered that the Sungok orebody had a larger sulfide mineral grain size than the Wolgok orebody because the time constant of the Sungok orebody was larger.

• Korean Journal of Agricultural Science
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• v.41 no.4
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• pp.321-326
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• 2014

The aim of this study was to investigate which hydroponic system is the optimum for growth and photosynthetic characteristics of Angelica gigas during experiment. Angelica gigas 'Manchu' were sowed and managed under a growth room chamber. The environmental conditions (temperature $22^{\circ}C/18^{\circ}C$ (day/night), relative humidity 50-70%, photosynthetic photon flux density (PPFD) $120{\pm}6{\mu}mol\;m^{-2}s^{-1}$) were maintained for 3 weeks. Forty eight seedlings with 4-5 leaves were transplanted in deep flow technique (DFT), substrate, and spray culture systems [culture bed: 800 (L) ${\times}$ 800 (W) ${\times}$ 400 mm(H)] under $150{\pm}5{\mu}mol\;m^{-2}s^{-1}$ PPFD provided with fluorescence lamps and cultivated for 11 weeks. At the end of the experiment, fresh and dry weights, leaf lenghth and width, SPAD, root fresh, and dry weights, and root volume of Anglica gigas were measured. Photosynthetic rate of Anglica gigas were measured with portable photosynthesis systems to investigate optimum PPFD, $CO_2$ concentration, and air temperature conditions. Fresh and dry weights of Anglica gigas grown in substrate were significantly greater than DFT-treated, but there were not significant with spray treatment. Leaf photosynthesis of Anglica gigas showed the tendency to sharply increase as PPFD was increased from 50 to $200{\mu}mol\;m^{-2}s^{-1}$. Though $CO_2$ saturation point was around $1000-1200{\mu}mol\;mol^{-1}$, increase in air temperature from 16 to $26^{\circ}C$ did not quite affect photosynthesis of Anglica gigas. In conclusion, Anglica gigas may be optimally cultivated with a spray culture system as air temperature, PPFD, and $CO_2$ concentration for environment are controlled at $20{\pm}3^{\circ}C$, $150{\mu}mol\;m^{-2}s^{-1}$, and around $1000{\mu}mol\;mol^{-1}$ for mass production.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.377-385
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• 2020

Recently, wheat consumption has been increasing in Korea, requiring increased production. Nitrogen fertilization is a critical determinant in crop yield; therefore, it is necessary to optimize the nitrogen fertilization regime with current trends that emphasize the minimum impact of nitrogen fertilizer on the environment. In this study, both nondestructive spectral analysis using a hyperspectral camera and growth analysis were performed to determine the optimal N top-dressing rates after heading. The nitrogen application regimes consisted of three conditions according to the secondary top-dressing rate: N_4:3:0 (0 kg 10 a^-1), N_4:3:3 (2.73 kg 10 a^-1), and N_4:3:6 (5.46 kg 10 a^-1). Subsequently, growth and physiological investigations were performed at the jointing, heading, and ripening stages of wheat, and spectral investigations were conducted. On April 29, as the nitrogen fertilization rate was increased to N_4:3:3 and N_4:3:6, plant height and grain yield increased by 4% and 8%, and 8% and 52%, respectively, compared to those under N_4:3:0. Leaf area index and SPAD value also increased by 13% and 24%, and 32% and 43%, respectively. The R (red), G (green), and B (blue) of leaf color were lowered by 15, 11, and 4 in N_4:3:3 and 44, 34, and 18 in N_4:3:6, respectively, as compared to the control. Grain yield was the highest at high top-dressing (N_4:3:6), however, there was no difference between no top-dressing (N_4:3:0) and intermediat top-dressing (N_4:3:3). The reflectance analyzed using a hyperspectral camera showed a difference in the near-infrared (NIR) region on March 19, and on April 29, there was a difference both in the visible light region greater than 550 nm and the NIR region. Vegetation indices differed according to fertilization regime, except for the greenness index (GI). The results of this study showed that not only growth and physiological analysis but also spectral indices can be used to optimize the nitrogen top-dressing rate.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.928-936
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• 2010

This study was conducted to select efficient foliage plants for improving indoor environment conditions through the investigation of physiological responses including photosynthetic rate according to temperature, light intensity, and $CO_2$ level. Eight popular foliage plants used in this study were $Hedera$ $helix$ L., $Cissus$ $rhombifolia$ Vahl, $Ficus$ $benjamina$ L. 'Hawaii', $Syngonium$ $podophyllum$ Schott 'Albo-Virens', $Dieffenbachia$ $sp.$ 'Marrianne', $Pachira$ $aquatica$ Aubl., $Spathiphyllum$ $wallisii$ Regel, and $Scindapsus$ $aureus$ Engler. Photosynthetic rate and transpiration rate of the plants subjected to various light intensities (0, 25, 50, 75, 100, 150, 300, and $600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD), $CO_2$ levels (0, 50, 100, 200, 400, 700, and $1,000{\mu}molCO_2{\cdot}mol^{-1}$), and two different temperatures (16 and $22^{\circ}C$) were measured. In addition, various parameters in relation to photosynthesis were calculated from the measured data. As a result, the patterns of photosynthesis varied among 8 foliage plants according to light intensity, $CO_2$ level, and temperature. Most foliage plants except $Dieffenbachia$ had high levels of apparent quantum yield, which represents the photosynthetic rate under low light intensity (PPFD $0-100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). $Hedera$ $helix$, $Ficus$ $benjamina$, $Pachira$ $aquatica$, and $Spathiphyllum$ $wallisii$ exposed to high light intensity (PPFD $200-600{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) showed high levels of photosynthesis. $Cissus$ $rhombifolia$ and $Syngonium$ $podophyllum$ were low in $CO_2$ fixation efficiency compared to the other 6 foliage indoor plants. $Hedera$ $helix$ and $Spathiphyllum$ $wallisii$ showed high photosynthetic rate under high $CO_2$ level and vigorous photosynthesis was also observed in $Ficus$ $benjamina$ and $Pachira$ $aquatica$ grown under $22^{\circ}C$. Considering characteristics of indoor environment such as low light, high $CO_2$ level, and low relative humidity, therefore, $Hedera$ $helix$, $Spathiphyllum$ $wallisii$, $Ficus$ $benjamina$, and $Pachira$ $aquatica$ were efficient indoor foliage plants to improve indoor environmental conditions.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.654-661
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• 1999

Background : The upper respiratory tract is the primary target organ of various airborne pollutants and is easily accessible part of the respiratory tract, and also is the predominant structure where chronic cough originates. The nasal peak inspiratory flow(PIFn), which is the peak inspiratory flow via nose with nasal mask and spirometry, could be a reliable parameter of nasal obstruction. The validity of PIFn has been evaluated in several studies by assessing the correlation between PIFn measurements and other parameters of nasal air flow. This study was designed to show the reproducibility of PIFn, the difference of PIFn between patients with chronic cough and normal subjects, and the usefulness of PIFn in the evaluation of nasal obstruction in patients with chronic cough. Methods : PIFn was measured by spirometry with nasal mask, twice a day for 3 consecutive days in 7 young normal subjects to evaluate validity of the test. In 32 patients with chronic cough and 25 age-matched normal subjects, PIFn and pulmonary function test($FEV_1$, $FEV_1%$ pred, FVC, and FVC% pred) were measured at first visiting. Results : Values of PIFn, $FEV_1$, and FVC were nearly constant in 7 young normal adults. Patients with chronic cough were 32 (14 males and 18 females) and the mean age was $41.4{\pm}15.9$ years. Normal subjects were 32(22 males and 10 females) and the mean age was $39.8{\pm}18.6$ years. There was no significant difference of age and pulmonary function test between patients with chronic cough and normal subjects(p<0.05). The PIFn values in patients with chronic cough was significantly lower than those of normal subjects($2.25{\pm}0.68\;L/sec$ vs. $2.75{\pm}1.00\;L/sec$ ; p=0.02). The postnasal drip syndrome(PNDS) comprised the majority of patients with chronic cough(27). The PIFn in patients with PNDS was significantly lower than that of normal subjects (mean$\pm$SD ; $2.18{\pm}0.66$ vs. $2.75{\pm}1.00\;L/sec$, p=0.006). Conclusion : There was a significant difference of PIFn between patients with chronic cough and normal subjects. Among the patients with chronic cough, patients with PNDS showed the most significant difference with normal subjects in PIFn. The PIFn could be a useful parameter of nasal obstruction in patients with chronic cough, especially in patients with PNDS.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.14-20
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• 1996

Growth, nutrient uptake and photosynthesis as affected by submersion of shoot in pickerel weed (Monochoria vaginalis Presl.) were determined. The shoots of pickerel weeds in hydroponic culture were subjected to the submerged or emerged condition at 3- or 5-leaf stage for 8 or 10 days. Under submerged condition, growth in plant height was enhanced, but leaf number, leaf area, fresh and dry weight were reduced compared to those under the emerged condition. Similar responses in growth to submergence were obtained with the pickerel weeds rooted in the soil. Under submergence, chlorophyll content increased during the first 2 days, but thereafter remarkably decreased at 3-leaf stage and after the first 4 days at 5-leaf stage. Compared to the emerged condition, uptakes of $NH_4\;^+$-N, $NO_3\;^-$-N, $P_2O_5$ and $K^+$ were reduced, but uptakes of $Ca^{++}$ and $Mg^{++}$ increased under the submerged condition. Photosynthetic rate of shoot under water, measured by $CO_2$electrode, showed the maximum by 210 ${\mu}$moles $HCO_3\;^-$/g F.W. at the 8th day after submergence(DAS) at 3-leaf stage and 320 ${\mu}$moles $HCO_3\;^-$/g F. W. at 6 DAS at 5-leaf stage. These results indicate that pickerel weeds grow much better when the shoot is air-exposed and are less tolerable to submergence at 3 leaf-stage than at 5-leaf stage.