• Clean Technology
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• v.9 no.3
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• pp.133-144
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• 2003

In this study, Insoluble catalyst electrode for oxide systems were manufactured, by using of them, carried out experiments on electrolytic treatment of dyeing wastewater containing persistent organic compounds, and then made a comparative study of the efficiency of treatment for environmental pollutants and whether each of them is valuable of not as an electrode for soluble electrode(Fe, Al) and insoluble electrode(SUS, R.C.E; Replaced Catalyst Electrode) which were used in the electrolytic system. Besides, it was investigated the conditions for electrolytic treatment to find the maximum efficiency of electrolytic treatment. As the result of this study, by using of insoluble catalyst electrode for oxide can solved the stability of electrode that is one of the greatest problems in order to put to practical use of electrolysis process in the treatment of the sewage and wastewater and the result runs as follows; 1. The durability of insoluble catalyst electrode(R.C.E) can be verified the most favorable when the molar ratio of $RuO_2-SnO_2-IrO_2-TiO_2$(4 compounds system) is 70/20/5/5. 2. The efficiency of treatment was obtained a more than 90% goodness for CODMn and also a good results for T-N removal in the experimental conditions of the distance of electrode 5 mm, time of electrolysis 60 minutes, permissible voltage 10V, processing capacity $0.5{\ell}$.

• Clean Technology
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• v.18 no.4
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• pp.398-403
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• 2012

Selective nitrification and granulation have been carried out in a pilot scale air-lift sequencing batch reactor (SBR) for stable and economical nitrogen removal from wastewater. The SBR showed about 100% nitrification efficiency up to 1.0 kg ${NH_4}^+-N/m^3{\cdot}d$, about 90% efficiency at 1.0-2.0 kg ${NH_4}^+-N/m^3{\cdot}d$, and it was less than 90% when the load was higher than 2.0 kg ${NH_4}^+-N/m^3{\cdot}d$. Nitrite accumulation was induced by selective inhibition of nitrite oxidizing bacteria by free ammonia inhibition and dissolved oxygen limitation. For the purpose, high nitrite ratio (> 0.95) was obtained by keeping the pH higher than 8.0 and dissolved oxygen lower than 1.5 mg/L. In addition, sludge granulation was achieved by keeping reactor settling time to 5 minutes to wash out poor settling sludge and to promote the growth of granulation sludge. The operation accelerated sludge granulation and the sludge volume index (SVI) decreased and stably maintained to less than 75 in 60 days.

• Journal of Periodontal and Implant Science
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• v.28 no.3
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• pp.389-401
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• 1998

In this study, 21 patients diagnosed as adult periodontitis were divided into 4 groups. One quadrant with an average of 6mm deep pocket depth was chosen from each individual - Group A inserted tetra-cycline fiber after removing supragingival calculus while group RP had calculus removal and root planning alone. Group RP+A received combination of these treatments while group C received none. Plaque index, bleeding on probing, pocket depth, attachment level, and distribution of subgingival plaque were compared and evaluated among these groups at periods of first visit, 4th week and 8th week. The results were as follows ; 1. Plaque index and bleeding on probing improved after treatment and no significant difference was found between the groups. 2. When comparing the change in pocket depth between the groups, the use of tetracycline fiber showed significant reducton in pocket depth comparable to root planing. Combined therapy of tetracycline fiber and root planing showed synergistic effect in pocket depth reduction. 3. When comparing the change in attachment level between the groups, the use of tetracycline fiber showed significant increase in clinical attachment level comparable to root planing, but no synergistic effect was found in the combined therapy. 4. When comparing the change in the motile bacteria ratio between the groups, group RP and group RP+A showed significant decrease compared with control group. 5. There were no severe adverse effects from using tetracycline fiber, except for a few patient who experienced mild discomfort. In summary, the use of local adminstration of tetracycline fiber in adjunction to mechenical treatment can be effective for adult periodontitis.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1983.05a
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• pp.6.3-6
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• 1983

A total of 287 patients with foreign body in the air and food passage was treated in our unit between 1972 and 1982 and the following results were obtained : 1) The ratio between food and air passage was about 8 : 1. 2) The most common foreign bodies in the esophagus were coin (55.8%) and bone (28.5 %). Beans were the most common in the air passage (39.4%). 3) In sex distribution, there was no significant difference between male and females in the esophageal foreign bodies, but in the air passage male were prevalent (M : F = 57.9% : 42.1%). 4) In the age incidence, 61.8 % of the esophageal foreign bodies and 71 % of the foreign bodies in the air passage were under 5 Years of age. 5) The most prevalent site of Lodgement in the esophagus was the first narrowing (82.3 %). In the air passage, bronchial foreign bodies were more common and the right bronchus was the more frequent site (2 : 1). 6) In duration of lodgement, 62.2 % of esophageal foreign bodies and 55.2 % of foreign bodies in the air passage were removed within one day. 7) The most common complication of foreign bodies in the air passage was pneumonia (55.5%). 8) The removal of the foreign bodies in the air passage was performed by ventilation - bronchoscopy (84.3%). Two of 38 cases expired.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1981.05a
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• pp.4.1-4
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• 1981

The statistical study was done on 74 cases of foreign bodies in the air passages, who visited the department of otolaryngology of SNUH during recent 5 years from 1975 to 1980. The result was as follows, 1) Of the total 74 cases, 55 cases were male and 18 cases were female. The ratio between male and female was 3 : 1. 41.8% of all-cases were under 2 years of age, 75.5% were under 3 years, and 83.6% were under 5 years. 2) Major symptoms on visit were dyspnea, cough, cyanosis. No significant symptoms was noted in 6.7%. Initial physical findings were coarse breathing sound, decreased breathing sound, and stridor. No abnormal physical findings were noted in 10.8%. 3) 48.6% of total cases visited hospital within 24 hours. There was one case who visited hospital over 2 years later. 4) Initial simple chest film showed atelectasis in 25.0%, emphysema in 32.8%, definite foreign body shadow in 17.2% and within normal limit in 17.2%. 5) 60.8% of total cases were vegetables, 15.5% were metals, 16.2% were fish bone, and 2.7 % were others. 6) Vegetables were most frequent foreign bodies in the cases under 5 years of age. 7) 40.5% of total cases were lodged in the right main bronchus, 31.0% were in the left main bronchus, 9.8% were in trachea and 6.7% were in multiple sites, 8) Foreign bodies were removed by ventilating bronchoscopy in 82.3%, by tracheostomy only in 2.7%, by tracheal suction in 2.7%, by spontaneous removal in 1.3%, by thorachotomy in 5.4% and 5.4% of total cases were expired.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.1-6
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• 2012

Down Stream K River has high COD (4-10 mg/L) and high $NH_3$-N concentration (3.5 mg/L during winter period). Although $NH_3$-N itself is not reported harmful at this level, it must be removed to meet drinking water standard (0.5 mg/L). We constructed a pilot plant modifying the processes of conventional drinking water facilities. Prechlorination and powdered activated carbon (PAC) dechlorination was adopted prior to a flocculation tank to remove ammonia and prevent disinfection byproducts (DBPs) formation. Also, GAC processes was included after sand filter to remove residual DOC. This pilot having a capacity of 36 ton/day was operated for one year. The GAC processes were successful to remove ammonia and many organic pollutants (DOC, MBAS, UV-254 nm absorbance, etc). Influent DOC concentrations were very high as 3~6 mg/L throughout the plant operation. It was impossible to achieve 1.0 mg/L effluent DOC, indicating that bed depth (2 m) should be increased to achieve more strict DOC quality standards. When $Cl_2$ dose was well controlled ($Cl_2/NH_3$-N ratio 10~11 on a weight basis), $NH_3$-N removal was 98% and THMs was very low possibly due to low free residual chlorine and PAC dechlorination.

• Korean Journal of Microbiology
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• v.34 no.4
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• pp.200-206
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• 1998

The distributions and characteristics of bacteria on the deodorizing biofilters were studied as a part of biofiltration research for odor gas removal. The odor gas originated from a currently operating nightsoil treatment plant were mainly nitrogenous compounds of ammonia and amines. The filter media were consisted various ratio of pine bark, nightsoil cast and compost, and were sampled before and after operation of 153 days. Before operation, the level of bacteria on nitrification agar medium, nutrient agar medium and thiosulfate agar medium were around $10^7{\sim}10^8cfu/g$ media. After operation, the level decreased but still high as $10^5{\sim}10^7cfu/g$ media. The bacteria from reactors before and after operations were either rod or coccus after growth on nitrification agar media. The 45 isolated heterotrophic bacteria were further characterized and Pseudomonas, Bacillus, Flavobacterium, Alcaligenes were dominant genera. Genus Alcaligenes was particularly dominant when the isolates were incubated on nitrification agar media first and then transfered to nutrient media. The portion of Alcaligenes in the biofilter increased after operation, and was higher in the media contained nightsoil cast, which showed better treatment than the media with pine bark only.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1063-1070
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• 2011

In this study, total of 5 different chemical amendments were evaluated for determining kinetic parameters and stabilization efficiency of heavy metals in aqueous phase. Standard solution of Cd and Pb ($100mg\;L^{-1}$) was mixed with various ratio of amendments (1, 3, 5, 10%) and heavy metal stabilization efficiency was monitored for 24hrs. All examined amendments showed over 90% of removal efficiency for both Cd and Pb except zerovalent iron (ZVI) for Cd (43-63%). Based on result of heavy metal stabilization efficiency, it was ordered as $CaCO_3$ > Dolomite > Zeolite > Steel slag > ZVI for both Cd and Pb in aqueous phase. For kinetic study, first order kinetic model was adapted to calculate kinetic parameters. In terms of reaction rate constants (k), zeolite showed the fastest reaction rate (k value from 0.4882 for 1% to 2.0105 for 10%) for Cd and ZVI (k value from 0.2304 for 1% to 0.5575 for 10%) for Pb. Considering reaction rate constant and half life for heavy metal stabilization, it was ordered as Zeolite > $CaCO_3$ > Dolomite > Steel slag > ZVI for Cd and $CaCO_3$ > Dolomite > Steel slag > Zeolite > ZVI for Pb. Overall result in this study can be interpreted that lime containing materials are more beneficial to remove heavy metals with high efficiency and less time consuming than absorbent materials.

• The Journal of Korean Institute of Information Technology
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• v.15 no.12
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• pp.157-164
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• 2017

Mobile ECG signal measurement is a technique to measure small signals of several mV, and many studies have been conducted to remove noise including wandering scheme. Removal of the equipotential line noise caused by shaking or movement of the electrode cable is one of the core research contents for the electrocardiogram measurement. In this study, we proposed a modified step-size of combined NLMS(normalized least squares) and DLMS(delayed least squares) adaptive filter to eliminate baseline noise from ECG signals. The proposed method mainly adjusts initial filter step-size to reduce distortion of original ECG signals characteristic after eliminating baseline noise. The modified filter step-size is scaled by filter order size and distortion minimization factor. This method is suitable for portable ECG device with a small processor and less power consumption. This technique also decreases computation time which is essential for real-time filtering. The proposed filter also increase the signal to noise ratio (SNR) compared to conventional NLMS filter.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1545-1557
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• 2021

Crops show sensitive spectral characteristics according to their species and growth conditions and although frequent observation is required especially in summer, it is difficult to utilize optical satellite images due to the rainy season. To solve this problem, Constrained Cloud-Maximum Normalized difference vegetation index Composite (CC-MNC) algorithm was developed to generate periodic composite images with minimal cloud effect. In thisstudy, using this method, monthly Sentinel-2A/B Normalized Difference Vegetation Index (NDVI) composite images were produced for paddies and high-latitude cabbage fields from 2019 to 2021. In August 2020, which received 200mm more precipitation than other periods, the effect of clouds, was also significant in MODIS NDVI 16-day composite product. Except for this period, the CC-MNC method was able to reduce the cloud ratio of 45.4% of the original daily image to 14.9%. In the case of rice paddy, there was no significant difference between Sentinel-2A/B and MODIS NDVI values. In addition, it was possible to monitor the rice growth cycle well even with a revisit cycle 5 days. In the case of high-latitude cabbage fields, Sentinel-2A/B showed the short growth cycle of cabbage well, but MODIS showed limitations in spatial resolution. In addition, the CC-MNC method showed that cloud pixels were used for compositing at the harvest time, suggesting that the View Zenith Angle (VZA) threshold needsto be adjusted according to the domestic region.