• Korean Chemical Engineering Research
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• 제50권3호
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• pp.535-544
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• 2012

수평 여과매체를 사용한 케이크 여과에서는 침전이 수반된다. 이 침전 현상을 고려하지 않을 경우 여과기간의 케이크 평균비저항 값이 두 배 이상까지도 잘못 측정될 수 있다. 저자의 전번 논문에서는 여과기간에 침전으로 인해 케이크에 들어가는 현탁액의 고체분율이 변화한다는 것을 이론적으로 주장하였으나, 그 변화가 어느 정도인지를 알아내지 못하였다. 이 논문에서는 먼저 여과-투과 실험방법에 대한 분석에서 투과기간에 측정된 케이크 평균비저항 값이 옳다는 것을 여러 방법으로 증명하고, 여과기간에 통상적인 방법으로 측정된 평균비저항 값은 여과가 진행되는 순간의 현탁액의 고체분율 대신 초기 고체분율을 사용하므로 정확하지 못하다는 것을 입증하였다. 여과와 투과에서 측정된 실험값을 사용하여, 여과 진행 동안 침전에 의해 변화한 현탁액의 고체분율을 계산하였다. 그 후 여과 진행 동안 측정한 현탁액의 높이 변화 값과 이 논문에서 새로 만든 수식을 사용하여 여과 진행 중의 현탁액 고체분율을 결정하였다. 두 가지 방법으로 결정된 현탁액의 고체분율을 비교하여 두 가지가 거의 일치함을 입증하였다.

• 한국지반공학회논문집
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• 제26권6호
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• pp.21-28
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• 2010

화강풍화토는 가장 일반적인 흙의 종류이다. 비등방성 화강풍화토의 응력-변형-강도를 측정하는 것은 사면, 옹벽, 굴착의 변형과 안정을 위하여 매우 중요하다. 불포화 강도특성을 알기 위하여 일련의 불포화 배수삼축압축시험을 시행하였다. 시험시료는 다짐방향에 각각 0, 45, 90도의 축방향각을 갖도록 하였다. 등방압축을 받는 시료의 축변형률은 다짐방향에 의하여 크게 영향을 받으며 이차압축과정에는 시간의존성은 다짐방향과 관계가 거의 없다. 삼축압축강도와 변형에 미치는 다짐방향의 영향은 저구속압과 포화토에서 더 확연한것으로 나타났다. 다짐방향과의 각도를 고려하는 불포화화강풍화토의 강도를 추정하는 방법을 제안하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.85-85
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• 2020

South Korea experiences few large scale erosion and sedimentation problems, however, there are numerous local sedimentation problems. A reliable and consistent approach to modelling and management for sediment processes are desirable in the country. In this study, field measurements of sediment concentration from 34 alluvial river basins in South Korea were used with the Modified Einstein Procedure (MEP) to determine the total sediment load at the sampling locations. And then the Flow Duration-Sediment Rating Curve (FD-SRC) method was used to estimate the specific degradation for all gauging stations. The specific degradation of most rivers were found to be typically 50-300 tons/㎢·yr. A model tree data mining technique was applied to develop a model for the specific degradation based on various watershed characteristics of each watershed from GIS analysis. The meaningful parameters are: 1) elevation at the middle relative area of the hypsometric curve [m], 2) percentage of wetland and water [%], 3) percentage of urbanized area [%], and 4) Main stream length [km]. The Root Mean Square Error (RMSE) of existing models is in excess of 1,250 tons/㎢·yr and the RMSE of the proposed model with 6 additional validations decreased to 65 tons/㎢·yr. Erosion loss maps from the Revised Universal Soil Loss Equation (RUSLE), satellite images, and aerial photographs were used to delineate the geospatial features affecting erosion and sedimentation. The results of the geospatial analysis clearly shows that the high risk erosion area (hill slopes and construction sites at urbanized area) and sedimentation features (wetlands and agricultural reservoirs). The result of physiographical analysis also indicates that the watershed morphometric characteristic well explain the sediment transport. Sustainable management with the data mining methodologies and geospatial analysis could be helpful to solve various erosion and sedimentation problems under different conditions.

• 상하수도학회지
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• 제23권5호
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• pp.517-526
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• 2009

This research has been conducted to investigate the characteristics of hydraulic behavior within the PAC contactor, the rectangular shape sedimentation basin without inclined tube and the other one with inclined tube those are parts of demonstration plants(capacity : $2,000m^3/d$) in Korea Institute of Water and Environment. As results of tracer tests, the flow within PAC contactor was evaluated to divided into plug flow and dead space distinctly, and characteristics of dead space was close to that of CSTR(Complete/continuous Stirred Tank Reactor). Also, considering Reynolds number, Froude number, Morill, Modal, NCSTR Inex and plug flow/mixed flow fraction, in the case of the rectangular shape sedimentation basin without inclined tube, the characteristics of flow pattern was close to CSTR. On the other hand, in the case of the basin with inclined tube, the region of CSTR decreased precisely compared with the case of no-tube. Until now we have recognized that the inclined hydraulic structure just reduces the surface loading rate within a sedimentation basin. Actually besides, the inclined structure have an important effect on the hydraulic behavior within the basin.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1446-1451
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• 2008

The clay found in the river or in any waste water treatment plant usually have a very high content of water. A large amount of sediments hinder the navigation in river. In waste water treatment plant, there is requirement of settling the thick sludge. These problems are overcome by using rapid means of sedimentation and settling. This paper focus on how method of Electrokinetic sedimentation can be made faster. Sedimentation using Electrokinetic phenomenon has been discussed with varied voltage applied and effect and dose of coagulant in increasing the process. The experimental test has been carried out at water content that are generally present in the case of river and small canals carrying waste water. This paper also focus on different heavy metals concentration during the process and the power aspects of process. A series of experiment were done to support the proposed theory and how a bubble formation could hinder the purpose of experiment.

• 한국세라믹학회지
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• 제47권3호
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• pp.232-236
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• 2010

In recent years abrasive water jet (AWJ) has received significant attention as a technology used in the manufacturing industry for cutting materials. In this paper we report the development of a new preparation method of abrasives for water jet by using an air bubbling sedimentation rate control technique. The SiC abrasives prepared by an air bubbling sedimentation rate control technique using latex resin are found to be superior to the conventional abrasives not only in surface roughness uniformity but also in lifetime. The AWJ test results also show that the former has also better impact-resistance and wear-resistance than the latter.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 1996년도 학술발표회 논문집
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• pp.689-694
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• 1996

새만금지구의 조류 변화와 만경강, 동진강의 부유사유입의한 퇴적 과정을 알아보았다. 퇴적과정은 새만금지구해역의 조석잔차류와 수온, 염분에 의한 잔차류, 바람에 의한 잔차류성분을 포함한 흐름 성분과 입자의 침강속도를 고려한 3차원 수치실험에 의하여 재현하였다. 계산에서 안정성이 높고, 오차가 축적되지 않고, 복잡한 경계조건에서도 적용이 간단하다는 특성이 있는 Monte Carlo 방법을 사용하여 부유사의 분산, 퇴적과정을 수치실험한 결과와 농어촌진흥공사의 관측결과와 거의 유사하였다.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.999-1004
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• 2011

폭발법으로 얻어진 나노다이아몬드가 용매 내에 균일하게 분산되고, 일정 시간 침강이 이루어지지 않고 유지할 수 있도록 하고자, 표면에 카르복시기, 하이드록시기, 아민기 등의 기능기를 형성시킴으로써 나노다이아몬드의 활용성을 증대시키고자 하였다. 화학반응을 통하여 표면에 형성된 기능기, 입자의 크기 모양 등의 확인은 적외선흡수 스펙트럼과, X레이회절, 전자현미경, 원자현미경으로 관찰하였고, 용매의 종류에 따른 분산 특성을 조사하였다.

• 한국수정란이식학회지
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• 제31권1호
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• pp.73-80
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• 2016

An in vitro assay following culture of endometrial epithelial cells is essential for understanding epithelial cell function in reproduction. Several diverse techniques have been developed for isolating endometrial epithelial cells, although an optimal technique has not been identified. In this study, we describe a sedimentation-adherence (S-A) isolation technique with a high-yield cell-separating ability to isolate endometrial epithelial cells from 8-week-old female C57BL/6 mice. We analyzed total cell number, viability, morphology, and expression of cytokeratin 18 as an endometrial epithelial cell-specific marker in cells isolated using a mechanical method compared to the S-A technique. There were no significant differences in the total number, viability, or morphology of the putative endometrial epithelial cells with either method. In contrast, significantly more endometrial epithelial cells harvested using the S-A method were positively stained for cytokeratin 18 than those isolated using the mechanical method. These results confirm that the S-A method is more efficient for retrieving endometrial epithelial cells than a mechanical method.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1998년도 추계학술발표강연 및 논문개요집
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• pp.48-48
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• 1998