• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1181-1189
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• 2022

Clouds are composed of tiny water droplets, ice crystals, or mixtures suspended in the atmosphere and cover about two-thirds of the Earth's surface. Cloud detection in satellite images is a very difficult task to separate clouds and non-cloud areas because of similar reflectance characteristics to some other ground objects or the ground surface. In contrast to thick clouds, which have distinct characteristics, thin transparent clouds have weak contrast between clouds and background in satellite images and appear mixed with the ground surface. In order to overcome the limitations of transparent clouds in cloud detection, this study conducted cloud detection focusing on transparent clouds using machine learning techniques (Random Forest [RF], Convolutional Neural Networks [CNN]). As reference data, Cloud Mask and Cirrus Mask were used in MOD35 data provided by MOderate Resolution Imaging Spectroradiometer (MODIS), and the pixel ratio of training data was configured to be about 1:1:1 for clouds, transparent clouds, and clear sky for model training considering transparent cloud pixels. As a result of the qualitative comparison of the study, bothRF and CNN successfully detected various types of clouds, including transparent clouds, and in the case of RF+CNN, which mixed the results of the RF model and the CNN model, the cloud detection was well performed, and was confirmed that the limitations of the model were improved. As a quantitative result of the study, the overall accuracy (OA) value of RF was 92%, CNN showed 94.11%, and RF+CNN showed 94.29% accuracy.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.511-519
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• 2022

In order to develop an air-stripping based remediation process to remove the TOC (Total Organic Carbon) in groundwater around the underground LPG storage cavern, the laboratory scale experiments at various conditions (change of air injection volume and temperature, the application of ultrasonic treatment, etc.) for two types of groundwater (initial TOC concentration of 608 mg/L and 153 mg/L, respectively). From results of experiment, as the air injection rate for stripping into groundwater increased from 2 L/min to 11 L/min and as the air-stripping time increased from 1 hour to 24 hour, the TOC removal efficiency of air-stripping increased. However, the TOC concentration of treated groundwater was higher than the discharge tolerance limit (100 mg/L) even after 24 hour stripping at the maximum air injection rate of 11 L/min. The main compounds of the TOC in groundwater were identified as methanol and propane and the long stripping time (more than 24 hour) was needed to separate the methanol from groundwater because of the affinity between water and methanol. At 20℃ and 4 L/min of air injection, the TOC removal efficiency increased to 59.1% after 24 hour air-stripping. When the temperature of groundwater increased to 30℃ and 40℃, the TOC removal efficiency increased up to 80.0% and 82.8%, suggesting that more than 24 hour air-stripping at 40℃ is needed to lower the TOC concentration to below 100 mg/L and the additional TOC removal process as well as the air-stripping is necessary. When the temperature increased to 60℃ and the ultrasonic treatment was conjugated with the air-stripping, the TOC removal efficiency increased to 87.8% within 5 hour stripping and the final TOC concentration (72.4 mg/L) was satisfied with the TOC discharge tolerance limit. The TOC removal efficiency for groundwater having low TOC concentration (153 mg/L) also showed similar removal efficiency of 89.7% (the final TOC concentration: 18.9 mg/L). Results in this study supported that the air-stripping conjugated with the ultrasonic treatment could remove successfully the TOC in groundwater around the underground LPG strorage cavern.

• Economic and Environmental Geology
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• v.56 no.2
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• pp.167-183
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• 2023

Gases originated from the final SNF (spent nuclear fuel) disposal site are very mobile in the barrier and they may also affect the migration of radioactive nuclides generated from the SNF. Mechanisms of gas-nuclide migration in the multi-barrier and their influences on the safety of the disposal site should be understood before the construction of the final SNF disposal site. However, researches related to gas-nuclide coupled movement in the multi-barrier medium have been very little both at home and abroad. In this study, properties of gas generation and migration in the SNF disposal environment were reviewed through previous researches and their main mechanisms were summarized on the hydrogeological evolution stage of the SNF disposal site. Gas generation in the SNF disposal site was categorized into five origins such as the continuous nuclear fission of the SNS, the Cu-canister corrosion, the oxidation-reduction reaction, the microbial activity, and the inflow from the natural barriers. Migration scenarios of gas in porous medium of the multi-barrier in the SNF repository site were investigated through reviews for previous studies and several gas migration types including ① the free gas phase flow including visco-capillary two-phase flow, ② the advection and diffusion of dissolved gas in pore water, ③ dilatant two-phase flow, and ④ tensile fracture flow, were presented. Reviewed results in this study can support information to design the further research for the gas-nuclide migration in the repository site and to evaluate the safety of the Korean SNF disposal site in view points of gas migration in the multi-barrier.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.35-45
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• 2023

In this study, the sludge formation in the wastewater drain from the advanced packaging process mechanisms are revealed as well as the key factors, materials, and sludge prevention methods using surfactant. Compared with that of conventional packaging process, advanced packaging process employ similar process to the semiconductor fabrication process, and thus many processes may generate wastewater. In specific, a large amount of wastewater may generate during the carrier wafer bonding, photo, development, and carrier wafer debonding processes. In order to identify the key factors for the formation of sludge during the advanced packaging process, six types of chemicals including bonding glue, HMDS, photoresist (PR), PR developer, debonding cleaner, and water are utilized and mixing evaluation is assessed. As a result, it is confirmed that the black solid sludge is formed, which is originated by the sludge seed formation by hydrolysis/dehydration reaction of HMDS and sludge growth via hydrophobic-hydrophobic binding with sludge seed and PR. For the sludge prevention investigation, three surfactants of CTAB, PEG, and shampoo are mixed with the key materials of sludge, and it is confirmed that the sludge formations are successfully suppressed. The underlying mechanism behind the sludge formation is that the carbon tails of the surfactant bind to PR with hydrophobic-hydrophobic interaction and inhibit the reaction with HMDS-based slurry seeds to prevent the sludge formation. In this regard, it is expected that various problems like clogging in drains and pipes during the advanced packaging process may effectively solve by the injection of surfactants into the drains.

• The Korean Journal of Zoology
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• v.18 no.2
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• pp.51-60
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• 1975

The present study was performed histologically and histochemically to observe the cutaneous mucous glands in the frog, Rana nigromaculata during metamorphosis. The cutaneous thssues including dermal plicae in the dorsal portions of the frog tadpoles at each metamorphosis stage were fixed in 10% buffered formalin at$4^{\circ}C$, embedded in paraffin wax, sectioned 4 $\mu$m thickness and stained with periodic acid-Schiff(PAS) and alcian blue (AB) at both pH 2.5 and pH 1.0. The results of observation were as follows: 1. The developments of cutaneous mucous glands of the frog tadpole were begun with appearance of gland cell nest in the dermis at metamorphosis XV stage and significant numerical increases could be seen at metamorphosis XX, XXIII and XXIV stages. 2. This cutaneous mucous gland of the frog tadpole could be divided into two types; A-type glands showed strong positivities to both PAS and AB at pH 2.5 in the gland body cells and to PAS in the gland neck cells, and B-type glands at AB pH 2.5 in the gland body cells. 3. In the A-type mucous glands, the reactivities of the glandular epithelial cells to both PAS and AB stain could be first seen at the metamorphosis XIX stage of frog tadpole. The reactivities of the glandular epithelial cells to both PAS and AB pH 2.5 were gradually increased according to the process of metamorphosis after XX stage of metamorphosis. 4. The B-type mucous glands were first seen at the XX stage and the reactivity of the glandular epithelial cells to AB at pH 2.5 was gradually increased according to the process of metamorphosis after XX stage. 5. The A-type and the B-type mucous glands were in the ratio of 99 : 1, 7 : 3 and 5.5 : 4.5 for each of metamorphosis XX, XXI-XXII and XXIII-XXV stages. 6. The remarkable development of the cutaneous mucous glands of the frog tadpoles might be needed to maintain water and electrolyte balances according to the change of way from aquatic life to amphibious.

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.43-60
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• 1968

In order to find the effects of nitrogen type (ammonium sulfate and urea fertilizer) and fertilized depth, (0~10cm, 0cm, 5~10cm, 10~15cm, 15~20cm, and 20cm below) on leaching and absorption of nitrogen in paddy soil, and growth and yields of rice, the pot culture experiment was carried out, using the variety Jaekun, one of the Korean leading variety. Experimental results were Summarized as follows: 1. No variations of the pH of percolating water were induced by the differences of nitrogen types and their fertilized depth (Table. 2). 2. The leaching of nitrogen was less in ammonium sulfate and top soil fertilizing plots than in urea and subsoil fertilizing plot, and the growth of rice in early stage was more promoted in ammonium sulfate and topsoil fertilizing plots (Table. 1, 7 and 8). 3. Leachng of nitrogen through the percolating water almost came to an end at the most numerous tiller stage (Table 1). 4. The absorption of nitrogen of each part of the rice plant in the harvesting stage correlated closely with the yields of each part (Table 5, 6, 9 and 10) and the leaching of nitrogen in the early stage was inversely proportion to the absorption of nitrogen of rice plant in the harvesting time (Table 1, 5, 6, 9 and 10). 5. The number of spikes was more numerous in ammonium sulfate plots than in urea plots on an average, so that the yields were higher in the ammonium sulfate plots than in urea plots although no differences in the grain number per spike were found in above two plots. The number of spikes was more numerous in topsoil fertilizing plots than in subsoil fertilizing plots, but the grain number per spike was less in former than in latter, so that no difference in yields was found. The absorption of nitrogen correlated closely with the yields in complete paddy grains (Table 5, 9, and 10). 6. At the ammonium sulfate fertilizing plots, the number of spikes was more numerous in topsoil fertilizing plots than in subsoil fertilizing plots, (among the each of the topsoil plots, 0~10cm and 5~10cm fertilizing plots kept more spikes than the 0cm fertilizing plots), but the grain number per spike was less in former than in latter (among the each of topsoil plots, no differences were found), so that no significant difference in yields was showed between the topsoil and subsoil fertilizing plots, but the results showed the tendency that the yields were highest in 0~10cm plots and the lowest in 20cm below plots. At the urea fertilizing plots, the number of spikes decreased in proportion to the increasing of fertilized depth, but no variations were found in the grain number per spike, so that the yields decreased in proportion to the increasing of fertilized depth. The absorption of nitrogen correlated closely with the yields in complete paddy grains (Table 5, 6, 9, and 10). 7. When fertilized in topsoil, the number of spikes was more numerous in ammonium sulfate plot than in urea plot, but the grain number per spike variated reversely, so that no differences were found in the yields between the ammonium sulfate and the urea plots, when fertilized in subsoil, both the number of spikes and the grain number per spike were larger in ammonium sulfate than in urea plot, so that the yields were also higher in ammonium sulfate plots (Table 5, 6, 9 and 10). 8. The weight of straw and its nitrogen absorption were higher in ammonium sulfate plot than in urea plot and decreased in proportion to the increasing of fertilized depth. Among the each of topsoil fertilizing plots, the 0~10cm and the 5~10cm fertilizing plots excelled the 0cm plot (Table 5, 6, 9 and 10). 9. No significant variations in the fertilizer treatments were found in the characters of heading date, maturing date, length of culm, length of spike, weight of empty grain, 1,000 grain weight, and one liter weight.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.9 no.1
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• pp.1-18
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• 1973

For regulating the depth of midwater trawl nets towed at the optimum constant speed, the changes in the shape of warps caused by adding a weight on an arbitrary point of the warp of catenary shape is studied. The shape of a warp may be approximated by a catenary. The resultant inferences under this assumption were experimented. Accordingly feasibilities for the application of the result of this study to the midwater trawl nets were also discussed. A series of experiments for basic midwater trawl gear models in water tank and a couple of experiments of a commercial scale gears at sea which involve the properly designed depth control devices having a variable attitude horizontal wing were carried out. The results are summarized as follows: 1. According to the dimension analysis the depth y of a midwater trawl net is introduced by $$y=kLf(\frac{W_r}{R_r},\;\frac{W_o}{R_o},\;\frac{W_n}{R_n})$$) where k is a constant, L the warp length, f the function, and $W_r,\;W_o$ and $W_n$ the apparent weights of warp, otter board and the net, respectively, 2. When a boat is towing a body of apparent weight $W_n$ and its drag $D_n$ by means of a warp whose length L and apparent weight $W_r$ per unit length, the depth y of the body is given by the following equation, provided that the shape of a warp is a catenary and drag of the warp is neglected in comparison with the drag of the body: $$y=\frac{1}{W_r}\{\sqrt{{D_n^2}+{(W_n+W_rL)^2}}-\sqrt{{D_n^2+W_n}^2\}$$ 3. The changes ${\Delta}y$ of the depth of the midwater trawl net caused by changing the warp length or adding a weight ${\Delta}W_n$_n to the net, are given by the following equations: $${\Delta}y{\approx}\frac{W_n+W_{r}L}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}{\Delta}L$$ $${\Delta}y{\approx}\frac{1}{W_r}\{\frac{W_n+W_rL}{\sqrt{D_n^2+(W_n+W_{r}L)^2}}-{\frac{W_n}{\sqrt{D_n^2+W_n^2}}\}{\Delta}W_n$$ 4. A change ${\Delta}y$ of the depth of the midwater trawl net by adding a weight $W_s$ to an arbitrary point of the warp takes an equation of the form $${\Delta}y=\frac{1}{W_r}\{(T_{ur}'-T_{ur})-T_u'-T_u)\}$$ Where $$T_{ur}^l=\sqrt{T_u^2+(W_s+W_{r}L)^2+2T_u(W_s+W_{r}L)sin{\theta}_u$$ $$T_{ur}=\sqrt{T_u^2+(W_{r}L)^2+2T_uW_{r}L\;sin{\theta}_u$$ $$T_{u}^l=\sqrt{T_u^2+W_s^2+2T_uW_{s}\;sin{\theta}_u$$ and $T_u$ represents the tension at the point on the warp, ${\theta}_u$ the angle between the direction of $T_u$ and horizontal axis, $T_u^2$ the tension at that point when a weights $W_s$ adds to the point where $T_u$ is acted on. 5. If otter boards were constructed lighter and adequate weights were added at their bottom to stabilize them, even they were the same shapes as those of bottom trawls, they were definitely applicable to the midwater trawl gears as the result of the experiments. 6. As the results of water tank tests the relationship between net height of H cm velocity of v m/sec, and that between hydrodynamic resistance of R kg and the velocity of a model net as shown in figure 6 are respectively given by $$H=8+\frac{10}{0.4+v}$$ $$R=3+9v^2$$ 7. It was found that the cross-wing type depth control devices were more stable in operation than that of the H-wing type as the results of the experiments at sea. 8. The hydrodynamic resistance of the net gear in midwater trawling is so large, and regarded as nearly the drag, that sweeping depth of the gear was very stable in spite of types of the depth control devices. 9. An area of the horizontal wing of the H-wing type depth control device was $1.2{\times}2.4m^2$. A midwater trawl net of 2 ton hydrodynamic resistance was connected to the devices and towed with the velocity of 2.3 kts. Under these conditions the depth change of about 20m of the trawl net was obtained by controlling an angle or attack of $30^{\circ}$.

• Journal of Korean Society of Forest Science
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• v.52 no.1
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• pp.1-30
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• 1981

The origin and development of adventitious roots was studied using hypocotyl and epicotyl cuttings of 34 species, 24 genus of woody plants. These cuttings obtained from young seedlings cultured in vials containing distilled water only. The several characteristics of cuttings materials studied are shown in Table 1. The results are summerized as follows: 1. The circumference shapes of cross-sections of hypocotyl and epicotyl cuttings can be divided into six categories, namely, round, irregular round, ellipse, irregular ellipse, square, and triangle. Species differences within a genus did not show any difference of hypocotyl and epicotyl cross-sections shape, however, a noticeable variation among genus or higher taxa. 2. The arrangements of vascular bundles in the cross-sections of hypocotyls or epicotyls were almost all collateral types and generally showed generic characteristics differing one to the other. However, there were some variations between species within the genus. Six models of vascular bundle arrangement were proposed for all the above speices. 3. The rooting portions of hypocotyl and epicotyl cuttings in this experimental materials can be grouped as follows: (1) Interfascicular parenchyma; (Thuja orientalis. T. orientalis for. sieboldii, Acer microsieboldianum, A. palmatum, A. saccharinum, Cercis chinensis, Lespedeza bicolor, Magnolia obovata, M. sieboldii, Mallotus japonicus, Staphylea bumalda) (2) Cambial and phloem parenchyma: (Chamaecyparis obtusa, C. pisifera, Albizzia julibrissin, Buxus microphylla var. Koreana, Cereis chinensis, Euonymus japonica, Firmiana platanifolia, Lagerstroemia indica, Ligustrum salicinum, L. obtusifolium, Magnolia kobus, M. obovata, Mallotus japonicus, Morus alba, Poncirus trifoliata, Quercus myrsinaefolia, Rosa polyantha, Styrax japonica, Styrax obassia) (3) Primary ray tissues; (Euonymus japonica, Styrax japonica) (4) Leaf traces; (Quercus acutissima, Q. aliena) (5) Cortex parenchyma; (Ailanthus altissima) (6) Callus tissues; (Castanea crenata, Quercus aliena, Q. myrsinaefolia, Q. serrata) 4. As a general tendency throughout the species studied, in hypocotyl cuttings, the adventitious root primordia were originated from the interfascicular parenchyma tissue, however, leaf traces and callus tissues were contributed to the root primordia formation in epicotyl cuttings. The hypocotyl cuttings of Ailanthus altissima exhibited a special performance in the root primordia formation, this means that cortex parenchyma was participated to the origin tissue. And in Firmiana platanifolia, differening from the other most species, the root primordia were formed at the phloem parenchyma adjacent outwardly to xylem tissue of vascular bundle system as shown photo. 48. 5. All the easy-to, or difficult-to root species developed adventitious roots in vials filled with distilled water. In the difficult-to-root species, however, root formations seemed to be delayed because they almost all had selerenchyma or phloem fiber which gave some mechanical hindrance to protrusion of root primordia. On the other hand, in the easy-to-root species they seemed to form them more easily because they did not have the said tissues. The rooting portions between easy-to-root and difficult-to-root species have not clearly been distinguished, and they have multitudinous variations. 6. The species structured with the more vascular bundles in number compared with the less vascular bundles exhibited delayed rooting. In the cuttings preparation, the proximal end of cuttings was closer to root-to-stem transition region, the adventitious root formation showed easier. 7. A different case occured however with the mature stem cuttings, in both the needle-leaved and the broad-leaved species. In the hypocotyl cuttings, parenchymatous tissues sited near the vascular bundles become the most frequent root forming portions in general and relevant distinctions between both species were hardly recognizable. 8. In the epicotyl cuttings, root primordia originated mainly in leaf traces in connection with cambial and phloems or callus tissues itself. In the hypocotyl cuttings, interfascicular parenchyma was the most frequent portion of the root primordia formation. The portions of root primordia had more connection with vascular cambium system, as the tissues were continuing to be developed.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.259-266
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• 1998

There are three different types of gynecological applicator sets available in microSelectron-high dose-rate(HDR) System by Nucletron; standard applicator set(SAS), standard shielded applicator set(SSAS), and Fletcher-Williamson applicator set(FWAS). Shielding effect of a SAS without shielding material was compared with that of a SSAS with shielding material made of stainless steel(density ${\varrho}=8,000kg/m^3$) at the top and bottom of each ovoid, and of a FWAS with shielding material made of tungsten alloy(density ${\varrho}=14,000kg/m^3$ at the top and bottom of each ovoid. The shielding effects to the rectum and bladder of these two shielded applicator sets were to be measured at reference points with an ion chamber and specially designed supporting system for applicator ovoids inside of the computerized 3-dimensional water phantom. To determine the middle point of two ovoids the measurement was performed with the reference tip of ion chamber placed at the same level and at the middle point from the two ovoids, while scanning the dose with the ion chamber on each side of ovoids. The doses to the reference points of rectum were measured at 20(Rl), 25(R2), 30(R3), 40(R4), 50(R5), and 60(R6) mm located posteriorly on the vertical line drawn from M5(the middle dwell position of ovoid), and the doses to the bladder were measured at 20(Bl), 30(B2), 40(B3), 50(B4), and 60(B5) mm located anteriorly on the vertical line drawn from M5. The same technique was employed to measure the doses on each reference point of both SSAS and FWAS. The differences of measured rectal doses at 25 mm(R2) and 30 mm(R3) between SAS and SSAS were 8.0 % and 6.0 %: 25.0% and 23.0 % between SAS and FWAS. The differences of measured bladder doses at 20 mm(Bl) and 30 mm(B2) between SAS and SSAS were 8.0 % and 3.0 %: 23.0 % and 17.0 % between SAS and FWAS. The maximum shielding effects to the rectum and bladder of SSAS were 8.0 % and 8.0 %, whereas those of FWAS were 26.0 % and 23.0 %, respectively. These results led to the conclusion that FWAS has much better shielding effect than SSAS does, and when SSAS and FWAS were used for gynecological intracavitary brachytherapy in microSelectron-HDR system, the dose to the rectum and bladder was significantly reduced to optimize the treatment outcome and to lower the complication rates in the rectum and bladder.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.206-211
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• 1983

This study was carried out to compare the feed utilization between pelleted and all-mash diet of similar composition by growing chickens. Day-old broilers (Hubbard) and egg-type chickens(Hy-line) of commercial strain were employed in this experiment. The results obtained were summarized as follows. 1. The chickens fed pelleted diets were heavier than those of birds fed all-mash diets. The Hubbard broilers and Hy-line chickens fed pelleted diets weighed 2,702g and 812g respectively, at 9 weeks of age. In comparison, the Hubbard broilers and Hy-line chickens fed all-mash diets weighed 2,571g and 777g respectively, at 9 weeks of age. 2. The pellet-fed chickens consumed more feeds than birds fed all-mash diets in both types of strain. Feed efficiencies (gain/feed) of Hubbard and Hy-line chickens were 0.38 and 0.26 in pellet feeding groups, and 0.36 and 0.25 in all-mash feeding groups, respectively. The Hy-line chickens fed pelleted diets drank more water than birds fed all-mash diets. 3. Pellet feeding groups produced more dry matter excreta as compared with all-mash feeding groups, reflecting the pattern of feed consumption by these chickens. Nitrogen retention ratio of the Hubbard and Hy-line chickens were 57-67% and 65-73%, respectively. Chickens fed pelleted diets showed 1-4% higher nitrogen retention than chickens fed all-mash diets. 4. The ME/GE ratio of the Hubbard and the Hy-line at 8 weeks of age were 73.4-74.3% and 82.8-83.8%, respectively. Pellet feeding groups showed 1% higher ME/GE ratio than all-mash feeding groups. 5. The dietary productive energy calculated from respiratory quotient was $94.1-102.6kca/kg^{\frac{3}{4}}$ BW/day in pellet feeding groups. The ratios of PE/GE were 41.3-48.9% in pellet feeding groups and 39.0-45.8% in all-mash feeding groups. 6. It appears that pelleting the all-mash diet increases feed consumption and body weight gain of growing chickens. Feed efficiency and energy utilization were also improved by pelleting process. More research work should be done to establish the relationship clearly between feed pelleting and heat increments.