• Membrane and Water Treatment
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• v.9 no.3
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• pp.173-179
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• 2018

Microcystin-LR, one of algal toxins induced by the eutrophication of a reservoir, is known to be harmful to human by adversely affecting our liver and brain. Hypochlorous acid is very efficient to remove Microcystin-LR in a clear well. The previous researches showed that CT, pH and temperature affected removal rate in batch tests. It was noted that hydrodynamic properties of clear well could also influence its removal rate. A mathematical model was built using an axial dispersion reactor model and software was used to simulate the removal rate. The model consisted of the second order differential equations including dispersion, convection, Microcystin-LR reaction with chlorine. Kinetic constants were obtained through batch tests with chlorine. They were $0.430{\times}10^{-3}L/mg/sec$ and $0.143{\times}10^{-3}L/mg/sec$ for pH 7.0 and 8.1, respectively. The axial dispersion reactor model was shown to be useful for the numerical model through conservative tracer tests. The numerical model successfully estimated the removal rate of Microcyctin-LR in a clear well. Numerical simulations showed that a small dispersion number, low pH and long hydraulic retention time were critical for higher removal rate with same chlorine dosage. This model could be used to optimize the operation of a clear well during an eutrophication season.

• The Korean Journal of Cytopathology
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• v.9 no.2
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• pp.213-219
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• 1998

Glycogen-rich clear ceil carcinoma of the breast is an unusual variant of carcinoma with a recorded incidence of $1.4{\sim}3%$ of breast carcinomas. The cytologic characteristics have not been well described. We report two cases of glycogen-rich clear cell carcinoma with corresponding fine needle aspiration(FNA) cytologic findings and compare them to infiltrating ductal carcinoma and other clear ceil malignancies with a review of literature. One was a 62-year-old woman exhibiting a palpable mass of the right breast. The smears showed atypical tight cell clusters and individually scattered single cells containing leanly or clear abundant cytoplasm with well defined cytoplasmic margins. Mild to moderate nuclear pleomorphism and a prominent nucleolus were present. The other was a 42-year-old woman who was admitted with a right breast mass. The smears showed moderately cellular, tightly cohesive tumor cells. The cytoplasmic outline was generally well demarcated. The tumor cells Contained foamy to clear abundant cytoplasm with large and small vacuoles. The nuclear pleomorphism was marked. Both tumors resected by modified radical mastectomy, were diagnosed as glycogen-rich clear cell carcinoma. Histologically, the clear cell nature of tumor cells were not characteristic enough to predict this type of the tumor. Some cytologic features can be distinguished other clear cell breast cancer from glycogen-rich carcinoma. Recognition of these unusual patterns in a breast FNAC should raise the suspicion of a clear cell carcinoma including glycogen-rich subtype. Cytological localization of glycogen using PAS and D-PAS staining may permit the correct Identification and differential diagnosis of this tumor.

• Journal of Advanced Navigation Technology
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• v.24 no.6
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• pp.527-532
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• 2020

Seoul terminal maneuvering area (TMA) that includes Incheon International Airport (ICN) and Gimpo International Airport is a very congested airspace with around 1,000 daily flights and the airspace blocked at the boundary between Incheon flight information region (FIR) and Pyongyang FIR. Consequently, with frequency radar vectorings, separation assurance in this airspace is complicated thus resulting in higher controller workload. In this paper, the conflict and collision risks in Seoul TMA are analyzed using recorded ADS-B data for past three years. Using the recorded trajectories, original flight plan procesures and routes are reconstructed and the risks are quantified using detect and avoid well clear (DWC) metric that is developed for large unmanned aircraft system. The region west of ICN was found to be the highest risk area regardless of the runway directions. In addition, merge and crossing points between procedures displayed relatively high risks.

• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.71-74
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• 2011

A 34-year-old female patient was presented with leg and hip pain for 6 months as well as voiding difficulty for 1 year. Magnetic resonance imaging revealed a well-demarcated mass lesion at L2-3. The mass was hypo-intense on T1- and T2-weighted images with homogeneous gadolinium enhancement. Surgery was performed with the presumptive diagnosis of intradural extramedullary meningioma. Complete tumor removal was possible due to lack of dural adhesion of the tumor. Histologic diagnosis was clear cell meningioma, a rare and newly included World Health Organization classification of meningioma usually affecting younger patients. During postoperative 2 years, the patient has shown no evidence of recurrence. We report a rare case of cauda equina clear cell meningioma without any dural attachment.

• Journal of Yeungnam Medical Science
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• v.29 no.1
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• pp.14-18
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• 2012

Background: The purpose of this study was to differentiate chromophobe renal cell carcinoma and clear cell renal cell carcinoma on helical CT. Methods: The CT images of 9 patients histopathologically proven to have chromophobe renal cell carcinoma and 20 patients with clear cell renal cell carcinoma were reviewed. The tumor sizes, margins, enhancement degrees and patterns, presence or absence of calcification, and tumor spread patterns (including perinephric changes, venous invasion, lymphadenopathy, and distant metastasis) were compared. Results: All the chromophobe renal cell carcinomas showed well-demarcated margins. Thechromophobe renal cell carcinomas showed milder enhancements than the clear cell renal cell carcinomas. The sensitivity and specificity for differentiating the chromophobe renal cell carcinoma from the clear cell renal cell carcinoma were 100 and 88%, respectively, when 101 Hounsfield units was used as the cut-off value in the corticomedullary phase, and 95 and 100% when a less-than-three-time enhancement change was used as a cut-off value in the corticomedullary phase (p<0.05). The chromophobe renal cell carcinomas (67%) tended to show a homogeneous enhancement whereas the clear cell renal cell carcinomas (85%) usually showed a heterogeneous enhancement (p<0.05). Statistical analysis revealed that the frequencies of the tumor spread pattern and calcification in the two subtypes didnot differ significantly (p>0.05). Conclusion: The CT findings of the chromophobe renal cell carcinomascompared to those of the clear cell renal cell carcinomas showed that there were mild enhancements in the corticomedullary phase, homogeneous enhancements, and well-demarcated margins.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.2
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• pp.213-218
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• 2008

Prediction models for post-chlorination require complicated information of reaction time, chlorine dosage considering flow rate as well as environmental conditions such as turbidity, temperature and pH. In order to operate post-chlorination process effectively, the correlations between inlet and outlet of clear well were investigated to develop prediction models of chlorine dosages in post-chlorination process. Correlations of environmental conditions including turbidity and chlorine dosage were investigated to predict residual chlorine at the outlet of clear well. A linear regression model and autoregressive model were developed to apply for the post-chlorination which take place time delay due to detention in clear well tank. The results from autoregressive model show the correlationship of 0.915~0.995. Consequently, the autoregressive model developed in this study would be applicable for real time control for post chlorination process. As a result, the autoregressive model for post chlorination which take place time delay and have multi parameters to control system would contribute to water treatment automation system by applying the process control algorithm.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.497-502
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• 2011

In order to examine the effects of combination of plug flow reactors in series on hydraulic characteristics, comparative tracer tests were conducted for the cases of the existing clear well and clear wells combined in series. From the results of tests, $T_{10}$/T within existing clear well was 0.62~0.68 depending on inlet flowrate, and that in the case of combination in series was 0.69~0.78. While it would be minor improvement in contact efficiency, it would be appropriate to combine two clearwell with pipe in series for expansion.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.37-44
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• 2021

In case of South Korea, the airspace which airlines can operate is extremely limited due to the military operational area located within the Incheon flight information region. As a result, safety problems such as mid-air collision between aircraft or Traffic alert and Collision Avoidance System Resolution Advisory (TCAS RA) may occur with higher probability than in wider airspace. In order to prevent such safety problems, an mid-air collision risk detection model based on Detect-And-Avoid (DAA) well clear metrics is investigated. The model calculates the risk of mid-air collision between aircraft using aircraft trajectory data. In this paper, the practical use of DAA well clear metrics based model has been validated. Aviation safety data such as aviation safety mandatory report and Automatic Dependent Surveillance Broadcast is used to measure the performance of the model. The attributes of individual aircraft track data is analyzed to correct the threshold of each parameter of the model.

• The Korean Journal of Cytopathology
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• v.17 no.1
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• pp.32-37
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• 2006

The objective of this study was to evaluate the cytomorphologic features of histologically confirmed clear cell carcinoma of the ovary and to evaluate the applicability of scrape or fine-needle aspiration cytology in making an intraoperative diagnosis. We reviewed scrape or fine-needle aspiration cytology findings in tissues taken from 6 patients with clear cell carcinoma of the ovary. The cytologic diagnosis was based primarily on findings in alcohol-fixed, hematoxylin-eosin (H-E) stained smears. The formation of material resembling a basement membrane was a characteristic finding in these smears. This extracellular hyaline material was stained light pink with H-E and was frequently found within tumor cell clusters as well as in the background material. Multinucleated giant cells were found occasionally. Each tumor cell had an abundant, clear, or granular cytoplasm with a distinct cellular membrane. Scrape cytology is a simple and rapid supportive method and could be helpful in diagnosing clear cell carcinoma of the ovary, especially when marked artifacts appear in the frozen section.

• The Korean Journal of Cytopathology
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• v.1 no.1
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• pp.103-110
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• 1990

A case of primary non-clear-cell adenocarcinoma of the vagina is reported occurring in a 65-year-old woman without exposure to diethylstilbestrol (DES) in utero. The adenocarcinoma did not appear to be associated with vaginal adenosis. It lacked clear cell component and interestingly composed of columnar epithelial cells of endocervical-type. Cytologically round to oval nuclei revealed one or more small nucleoli and fine granular chromatin pattern. Cytoplasm was plump, faintly basophilic and homogeneously stained. Histologically well differentiated columnar epithelial cells were arranged on trabecular pattern mainly, and also occasional glandular lumina and small solid sheets were found. Mitoses were hardly found.