• Journal of Korean Society on Water Environment
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• v.33 no.4
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• pp.434-440
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• 2017

In order to understand the characteristics of phosphorus in the paddy field, this study analyzed $PO_4-P$ and T-P concentrations of irrigation water, flooding water, and runoff from 2008 to 2010. The variation of phosphorous form within hydrologic cycle around the rice paddy field was investigated using the ratio of $PO_4-P$ to TP. In addition, the correlation between pH, EC, and DO in flooding water was analyzed and the factors affecting phosphorus form in paddy field were investigated. The concentration of T-P in flooding water was high during the survey period, and the concentration of T-P in runoff was assumed to be decreased by dilution due to irrigation and rainfall. On the other hand, the ratio of $PO_4-P$ to T-P was lower in flooding water than those of irrigation water and runoff, which was interpreted to be due to the fact that the phosphorus fertilizer was applied in the paddy field but the adsorption was rapidly occurred to the paddy field by the soil. The similar proportions of $PO_4-P$ to T-P in flooding water and runoff suggest that the form of phosphorus outflowed from the paddy is influenced by the form of phosphorus in the flooding water of paddy field. In addition, DO concentration in flooding water showed negative correlation with the concentrations of $PO_4-P$ and T-P. The effort to survey frequent irrigation water quality data is required for the analysis of phosphorus behavior in the paddy water system since concentration of phosphorous and DO in irrigation water would influence rhe form of phosphorous in flooding water and subsequent runoff.

• Journal of Korean Society on Water Environment
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• v.39 no.1
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• pp.20-29
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• 2023

This study analyzed the relationship between harmful cyanobacterial abundance and environmental factors in order to figure out the causes of the recent increase of cyanobacteria in Lake Dukdong from 2019 to 2021. Lake Dukdong, which is used as a drinking water source for Gyeongju City, has an algae alert system in place. Lake Dukdong has maintained good water quality, but algae alert level 1 (over 1,000 cells/mL) has been issued in recent years. As a result of Pearson correlation analysis (from May to Oct.), the cell density of Microcystis and Aphanizomenon, which form part of the most harmful cyanobacteria genus, were significantly positively correlated with the water temperature and water storage volume. T-test was performed to compare the data from 2016-2018 and 2019-2021 (from May to Oct.). The average density of harmful cyanobacteria cells increased about six-fold from 54 to 344 cells/mL. There were significant differences in water temperature, pH, total nitrogen (TN), total phosphorus (TP), TN/TP ratio, water storage volume, and cyanobacterial cell density. Water temperature increased from 19.2 to 22.8 ℃. TP concentration increased from 0.017 to 0.028 mg/L. The main cause of the recent increase of harmful cyanobacteria in Lake Dukdong is thought to be the increase in water temperature, TP concentration, and water storage volume from 2019 and 2021, resulting in more favorable conditions for cyanobacterial growth.

• The Journal of the Korea Contents Association
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• v.15 no.5
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• pp.436-443
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• 2015

The purpose of this study was to develop a self-diagnostic linearity quality control techniques of computed tomography (CT) by using measured CT number values from the various concentrations of iodine contrast media (CM) is diluted with distilled water under each condition of the tube voltage. The equipment was used for four-channel MDCT, the iodine concentration were using 300 mgI/ml, 350 mgI/ml, 370 mgI/ml and 400mgI/ml. Dilution of CM in distilled water was increased by each 5% until the maximum CT number values were measured. We applied the tube voltages for 90 kVp, 120 kVp, 140 kVp. As a result, we was obtained to the nearest linearity as 0.993 of correlation coefficient between the iodinated CM from 5% to 25% in 400 mgI/ml and the CT number values by 90 kVp. In conclusion, the proposed self-diagnostic linearity quality assurance technique by using iodine CM can be utilized to replace the AAPM CT performance phantom.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.1
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• pp.45-54
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• 1994

Cooking characteristics of ninety five non-glutinous and twenty six glutinous varieties were checked for understanding the varietal variation and interrelationship between the cooking and physicochemical properties of rice grain. The greatest variation in non-glutinous and glutinous rice varieties was observed in iodine blue value and the next large variation was recognized in amount of soluble solid in cooking water. Average values of volume expansion rate, iodine blue value and amounts of soluble solid in cooking water were different among domestic-bred japonica, Korean local and foreign rice varieties. Korean-bred japonica rice cultivars can be classified into several groups having same cooking quality such as <Jangan.·Seoan>, <Jinmi·Ilpum· Daeseong>, <Seohae·Namwon·Yeongduk>, <Chucheong·Bongkwang>, <Odae·Keumo> and <Hwacheong·Donghae·Palgong> by the distribution on the plane of 1st and 2nd principal components contracted from four cooking characteristics. Glutinous rice cultivars can be grouped into several different cooking quality types such as <Nonglimna 1·Suwon 357·Jodo·Inbujinado>, <Sangnambatbyeo·Jeokdo>, <Mujudo·Daigol-mochi>, <Daegoldo·Jindo>, <Jinbuchal·Colored Daegoldo>, <Shinseonchal·Hung-Tsan> and <Agudo·Irakdo> by the same analysis. Positive correlation was found between volume expansion rate and water absorption rate at 21℃. Iodine blue value was correlated negatively with amounts of soluble solid, and positively with amylose content in non-glutinous rices. In glutinous rices volume expansion rate showed positive relationship with iodine blue value, amounts of soluble solid and gel consistency. Iodine blue value was also positively correlated with alkali digestion value in glutinous rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.298-298
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• 2022

Milling is an important process that determines the quality of flour and is affected by milling machine type, scale, and tempering conditions. In addition, seed hardness is an important factor in determining the amount of tempering water and has been reported to affects flour yield and flour quality. There are reports that vitreousity is used as a measure to distinguish between soft and hard seeds, and the higher the vitreousity, the higher the protein contents. However, there is no established system for measuring viterousity of seeds and studies on the vitreousity and quality characteristics of flour are insufficient. Therefore, in this study, vitreousity, hardness, and milling characteristics were evaluated for 46 major domestic varieties, and their relationship was confirmed. After cutting the seeds using a seed cutter, vitreousity was measured, and seed hardness and flour particle size was measured using SKCS and PSI, respectively. As for the seed hardness index, 'Joa' was the lowest with 11.6, 'Yeonbaek' was the highest with 78.7. As for the milling yield, 'Saeol' had the lowest at 58.1%, and 'Hcjoong' had the highest at 88.6%. Seed hardness index and wheat flour production showed a high positively correlation, showing a similar to that of previous studies. Also, in flour particle size, 'Gobun' was the largest at 75.5 pm, and 'Joa' was the smallest at 43.1 um. Flour yield and flour particle size showed a high positively correlation. As a result of vitreousity, 'Hwangeumal' (55.2%), 'Saekeumkang' (59.1%), 'Baekkang' (52.3%), 'Goso' (44.6%), and 'Joa' (19.2%) were showed. Seed hardness and vitreousity showed a high positively correlation. Also as the vitreousity increased, the flour yield also showed a tendency to increase. In addition, as the seed hardness increased, particle size of the flour yield also showed a tendency to increase. It is thought that this result can be used as a measure to determine the quality of flour with vitreousity. However, further analysis of wheat varieties and methods of analyzing vitreousity are needed.

• Journal of Wetlands Research
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• v.12 no.2
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• pp.67-73
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• 2010

This study was performed to figure out what would be effective to maintain good water quality in the retention pond which was badly polluted before. In order to keep the good water quality of the retention pond it is necessary to prevent outer non-point source pollutants from flowing into the pond. In this study, we proposed to use porous slag as a blockage of the inflow into the pond from external non-point sources. We experimented with porous slag nets to see how the water is effected. With the results of the experiments, we found out there is a close correlation($r^2=0.9765$) between contact time and the removal rate of phosphorus, therefore we can conclude that contact time affects removal rate greatly. Synthetic wastewater, activated sludge effluent, and sewage were passed through a porous slag packed bed, both phosphorus and the suspended solid in water were removed highly. With the results of these tests, we proposed to set up a porous slag packed bed inside of the retention pond and revetment to prevent external non-point source pollutants flowing into the retention pond.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.139-160
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• 2024

The community structure of benthic macroinvertebrates in the Madongho Wetland protected area and inflow river located in Goseong-gun, Gyeongsangnam-do, was investigated in 2022 and 2023. We collected and identified 3,582 individuals belonging to 7 classes, 23 orders, 51 families, and 78 species over the 2 years from six sites. Gnorimosphaeroma naktongense was the dominant species with a ratio of 20%, and Caridina denticulata denticulata was the subdominant species with a ratio of 13.32%. Predators and gathering collectors were the most abundant in the functional feeding group, while sprawlers were the most diverse and numerous in the habitual dwelling group. Diversity, richness, dominance, and evenness were calculated as the biological indices. In addition, various biological water quality indices were calculated. Most insects in the inflow rivers belonged to group I in evaluating relative resistance and resilience, showing high colony stability. The results of analyzing the correlation between salinity and substrate particle size with brackish water species showed that Gnorimosphaeroma naktongense and Hediste japonica had a significant positive correlation with salinity, while Assiminea lutea and Neomysis awatschensis had a significant positive correlation with substrate particle size. Additionally, Sinelobus kisui was found to be a new record of Korean Tanaididae in this study.

• Journal of Korean Society on Water Environment
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• v.39 no.4
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• pp.329-342
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• 2023

Turbid water and suspended sediment (SS) load are having negative consequences such as water quality degradation and ecological damage, thus necessitating the establishment of management guidelines to reduce their impact. The present work investigates the spatio-temporal distribution of fish species and the effects of turbid water from 2011-2016 in the upper reaches of Soyang-Dam. The family Cyprinidae is the largest population in the study area, among which Zacco platypus and Zacco koreanus are the dominant species. The diversity of species is relatively abundant in the upper watershed, while the seasonal effect on the population distribution remains unclear. Using two main common components of the empirical orthogonal function (EOF) analysis, the distribution characteristics of 27 species at five survey sites are revealed. Zacco koreanus is found to be predominant at the upstream A-Naerincheon, while Zacco platypus and Rhinogobius brunneus are found to be predominant at the upstream B-Bukcheon. Disturbance of an aquatic ecosystem has a relatively greater impact in the downstream, as-compared to the upper area-the high proportion of forest area is decreased whereas that of agricultural and urbanized areas is increased. The patterns of representative species are changed according to the mid- to long-term effects of turbid water and SS. Accordingly, the significant correlation between the SS load and fish distribution EOF analysis indicates that it should be considered as a potential alternative that can overcome the limitations of impact assessment on turbid water to the Fish Assessment Index (FAI). A comprehensive study examining the long-term effects of SS load to the fish ecosystems with a systematic statistical analysis of sufficiently accumulated data at the national level is needed as future research.

• Korean Journal of Food Science and Technology
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• v.16 no.2
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• pp.223-227
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• 1984

Quality of flours of 166 different wheat varieties and breeding lines from the 1980-1982 year crop was evaluated with Mixograph. Protein content had a correlation coefficient of 0.68 with sedimentation value and of 0.67 with bread volume. Sedimentation value showed highly significant correlation (r = 0.74) with bread volume. Positive significant correlations were found between protein content and sedimentation value vs. Mixography water-absorption, however the protein content and sedimentation value were not consistently related with mixing time or height to peak. Mixograph curve of the flour in a cultivar showed the specific pattern regardless the environmental conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.259-262
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• 2002

Relationship between yield and palatability value measured by vice taster among 9 rice varieties was investigated to obtain basic information for production of rice with high quality in reclaimed paddy field. The rice yield showed a highly negative correlation with palatability value of milled rice (r=-0.49$^{**}$). The varieties of high palatability value tend to show low yield. The protein content of milled rice grown in reclaimed paddy field was higher than 7.5% mainly due to heavy fertilization of nitrogen and irrigation of eutrophicated water, The rice varieties such as Daeanbyeo, Jinpumbyeo and Sindongjinbyeo were recommendable only for higher yield, but in view of rice quality, Kwanganbyeo, Surabyeo and Nampyoengbyeo were more recommendable because of their lower protein content and higher palatability value.e.