• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.57-65
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• 2006

In this study, WASP6 was used to predict the water quality of the reservoir and the lake. This can help the managers make the right choice of water quality policy. The results through studying are below. Raw pollutant load caused by the tourists in pollutant load of the study area takes 91.66% and 92.75% in total amount T-N, T-P. It showed high value when compared to raw pollutant load by land and stock farm and it seems that the main contamination is the population of tourists. From the result of the prediction model, BOD will increase about 1.5 times, T-N and T-P will be 1.5 times in 2012. It means that some counter plan is needed to reduce pollutant load. Enviroment grade of Suokjeong reserver is in I~II grade which is in good condition comparatively. However, the water contamination will be in poor as the year passes. when considering T-N T-P, which are the nutrients to control eutrophication, the concentrated administration about contamination sources is in urgent.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.244-250
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• 2022

The changes in COD, TOC, T-P, and T-N concentrations were investigated for 2 years in the constructed wetland of Sookcheon, which was installed to improve the water quality of Daecheong reservoir in South Korea. In order to evaluate the pollution level of sediments in the wetland, settling velocity of particulate material (4 times) and sedimet material contents (6 times) were measured. COD and TOC concentrations increased slightly as they passed through wetlands, and T-N and T-P concentration tended to decrease. The material content (COD, T-P, T-N) of aquatic plants was higher in floating-leaved and free-floating macrophytes than emergent macrophytes. As a result of measuring the sedimentation rate of suspended materials, most of the suspended materials introduced into constructed wetlands were sedimented at a rapid rate in the first sedimentation site. In addition, sediment pollution of T-P and T-N in constructed wetland was in severe pollution. The sediments containing a large amount of T-P and T-N were eluted by physical and chemical environmental changes, which is likely to act as internal pollution sources in wetlands.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.9-15
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• 2011

The first objective of this study was to investigate water pollution status of Meejae Reservoir, Kunsan, irregularly receiving river water for agricultural and recreational purposes. The second objective of the study was to compare nutrient pollution loads of three nutrient sources: sediment leaching, non-point sources and the receiving water. Water analysis results showed that eutrophication was a concern especially in summer and the calculated TSI (secchi depth), TSI (chlorophyll-a), and TSI (TP) were 53.6, 57.7 and 56.7, respectively. Although there was no significant difference in seasonal mean values of sediment T-N, sediment T-P and sediment organic content, mean differences were found for sampling points. However, T-N and T-P sediment release flux showed seasonal mean differences, while showing no mean difference for sampling points. Water T-N data proportionally correlated with sediment T-N and sediment organic content data, while no statistical correlation was found for water T-P data. Comparison of nutrient loads calculated from three sources showed that the highest T-N load was occurred from the receiving (pumped) water while T-P loads of the receiving water and sediment release flux were similar. The first solution would be considered for the receiving water to improve the water quality of Meejae Reservoir. Reduction of nutrient flux from the sediment would be then tried as the second alternative solution.

• Bulletin of the Korean Chemical Society
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• v.35 no.8
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• pp.2471-2476
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• 2014

The aim of the present study is to explore the possibility of utilizing loess for the adsorption of total phosphorous (T-P) and total nitrogen (T-N) in water. Batch adsorption studies were performed to evaluate the influences of various factors like initial concentration, contact time and temperature on the adsorption of T-P and T-N. The adsorption data showed that loess is not effective for the adsorption of T-N. However, loess exhibited much higher adsorption capacity for T-P. At concentration of $1.0mgL^{-1}$, approximately 97% of T-P adsorption was achieved by loess. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher $R^2$ compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium $q_{e,cal}$ from pseudo-second-order kinetic model was relatively similar to the experimental adsorption equilibrium $q_{e,exp}$. The thermodynamic parameters such as free energy ${\Delta}G$, the enthalpy ${\Delta}H$ and the entropy ${\Delta}S$ were also calculated.

• Journal of the Korean Ceramic Society
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• v.18 no.2
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• pp.119-125
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• 1981

The thermostable resistor was made by using P.T.C.R-N.T.C.R. ceramics. In this study $BaTiO_3$ type P.T.C.R. ceramics and $SnO_2-Sb_2O_3$ type N.T.C.R. ceramics were cocrystallized in one body and electrical resistance was stable under the temperature variation between $25^{\circ}C$-40$0^{\circ}C$. The ceramics showed the most stable electrical resistance for the mal variation when the composition was 0.6P.T.C.R. $BaTiO_3$,$ 0.4SnO_2$ and 0.01 $Sb_2O_3$.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.41-46
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• 2004

The influence of pollutant loads on the water quality in Jeongeupcheon of Dongjin river was evaluated from Jan. 2002 to Dec. 2003 for two years. The range of pH in water was $6.87{\sim}7.53$. The EC level in upstream ranged from 83 to $95\;{\mu}s/cm$ with the highest value in autumn. The BOD level in upstream rang ed from 0.61 to 1.27 mg/L, which would be I grade according to water quality criteria by Ministry of Environment, but that in downstream was III grade. The average T-N level in midstream ranged from 6.10 to 10.84 mg/L which was the highest values throughout the stretch of the river. The average T-P levels ranged from. 0.41 to 0.98 mg/L Jeongeupcheon was suitable for the agricultural usage based upon one year analysis of river water quality. The effluent loads of BOD was high in midstream (J4) with 553 kg/day. The major sources of T-N loads were livestock, population, land use, and industry in order. The effluent loads of T-N was high in J4 by population and industry while that of T-N was high in J5 and J6 by livestock and land use. The delivered loads of T-N was high in downstream The delivered loads of T-P was low as compared with those of BOD and T-N. The delivery ratio of T-N ranged from 6 to 38%.

• Bulletin of the Korean Mathematical Society
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• v.34 no.3
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• pp.385-394
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• 1997

In this paper, we prove in p-uniforlmy convex space a fixed point theorem for a class of mappings T satsfying: for each x, y in the domain and for n = 1, 2, 3, $\cdots$, $$ \left\$\mid$ T^n x - T^n y \right\$\mid$ \leq a \cdot \left\$\mid$ x - y \right\$\mid$ + b(\left\$\mid$ x - T^n x \right\$\mid$ + \left\$\mid$ y - T^n y \right\$\mid$) + c(\left\$\mid$ c - T^n y \right\$\mid$ + \left\$\mid$ y - T^n x \right\$\mid$, $$ where a, b, c are nonnegative constants satisfying certain conditions. Further we establish some fixed point theorems for these mappings in a Hilbert space, in $L^p$ spaces, in Hardy spaces $H^p$ and in Sobolev spaces $H^{p,k}$ for 1 < p < $\infty$ and k $\leq$ 0. As a consequence of our main result, we also the results of Goebel and Kirk [7], Lim [8], Lifshitz [12], Xu [20] and others.

• KSBB Journal
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• v.18 no.2
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• pp.140-144
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• 2003

The artificial sewage was treated using a vertical flow zeolite-filled reed bed. The artificial sewage was fec into the reed bed for 10 minutes every 6 hours at the hydraulic load 314 L/$m^2$ \ulcorner day. The filtering height of the reed bed was 100 cm and the zeolite mixture was filled in the reed bed. The mixture consisted of the same volume of two types of zeolites ; 0.5~1 mm and 1~3 mm in diameter. Annual average removal efficiency was CO$D_{Cr}$ 95.1%, T-N 49.5%, $NH{_4^+}$-N 99.4% and T-9 56.4%. T-N removal efficiency decreaced remarkably from 73 to 27% with the operating time. Most of T-P was adsorbed in the uper area of the reed bed. The major portion of adsorbed phosphorus was composed of Fe-, Ca- and reductant selubele Fe-P.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.218-223
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• 2015

Purpose: To investigate whether volumetric analysis based on T2WI and contrast-enhanced (CE) T1WI can distinguish between isocitrate dehydrogenase-1 mutation-positive ($IDH1^P$) and -negative ($IDH1^N$) glioblastomas (GBMs). Materials and Methods: We retrospectively enrolled 109 patients with histopathologically proven GBMs after surgery or stereotactic biopsy and preoperative MR imaging. We measured the whole-tumor volume in each patient using a semiautomatic segmentation method based on both T2WI and CE T1WI. We compared the tumor volumes between $IDH1^P$ (n = 12) and $IDH1^N$ (n = 97) GBMs using an unpaired t-test. In addition, we performed receiver operating characteristic (ROC) analysis for the differentiation of $IDH1^P$ and $IDH1^N$ GBMs using the tumor volumes based on T2WI and CE T1WI. Results: The mean tumor volume based on T2WI was larger for $IDH1^P$ GBMs than $IDH1^N$ GBMs ($108.8{\pm}68.1$ and $59.3{\pm}37.3mm^3$, respectively, P = 0.0002). In addition, $IDH1^P$ GBMs had a larger tumor volume on CE T1WI than did $IDH1^N$ tumors ($49.00{\pm}40.14$ and $22.53{\pm}17.51mm^3$, respectively, P < 0.0001). ROC analysis revealed that the tumor volume based on T2WI could distinguish $IDH1^P$ from $IDH1^N$ with a cutoff value of 90.25 (P < 0.05): 7 of 12 $IDH1^P$ (58.3%) and 79 of 97 $IDH1^N$ (81.4%). Conclusion: Volumetric analysis of T2WI and CE T1WI could enable $IDH1^P$ GBMs to be distinguished from $IDH1^N$ GBMs. We assumed that secondary GBMs with $IDH1^P$ underwent stepwise progression and were more infiltrative than those with $IDH1^N$, which might have resulted in the differences in tumor volume.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.383-392
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• 2013

The objective of this study was to determine the effects of N:P ratio on primary productivity measured as chlorophyll-a (CHL) using the approach of In Situ Nutrient Enrichment Bioassays (NEBs) in Daechung Reservoir. The effects of NEBs on the N:P mass ratios were compared with the field data obtained from monthly-chemical monitoring during 2009~2012. The short-term NEBs showed that the response of primary productivity in the phosphorus spiked treatments (5, 15, 20 and 30 N:P ratios) were greater than the responses in the control (C) and nitrogen spiked treatment (N:P ratio=150, $T_{VI}$). The response in the nitrogen treatment (N:P ratio=150, $T_{VI}$) was less compared to control and all five treatments ($T_I{\sim}T_{VI}$). The outcomes of the NEBs suggest that phosphorus limited the phytoplankton growth and nitrogen addition inhibited the algal growth. In the analysis of nutrients and CHL from the ambient epilimnetic water in Daechung Reservoir, minimum N:P ratios resulted in maximum concentrations of CHL. Overall, our results suggest that the N:P ratio was the key factor in regulating the phytoplankton growth in NEB experiments.