• 한국해안해양공학회지
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• 제15권1호
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• pp.33-38
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• 2003

가덕도 인근 연안해역에서 채취된 해저 퇴적물과 연직방향으로 배열된 표사포획장치로부터 획득된 부유물질을 이용하여 탁도계 검교정을 수행하였다. 포획된 부유물질은 모래 함량이 약 6%인 해저 퇴적물에 비하여 주로 실트 및 점토로 조성되었으며, 해저면으로부터의 놀이가 증가함에 따라 세립화하는 경향을 보였다. 해저 퇴적물에 대한 탁도계 검교정 선형 회귀식의 기울기는 최소값으로 나타났으며, 수심별로 포획된 부유물질에 의한 선형 회귀식의 기울기는 포획 고도가 증가함(즉, 입도가 감소함)에 따라서 점진적으로 증가하였다. 이러한 결과는 해저 퇴적물에 대한 탁도계 검교정 결과로부터 부유물질 농도를 환산할 경우 과대추정의 오차가 발생되며, 본 연구해역의 경우에는 그 오차가 최대 25％까지 증가할 수 있다는 것을 보여준다. 따라서 해저 퇴적물보다는 수층에서 포획된 부유물질의 입도분포를 고려하여 보정된 검교정식을 적용하는 것이 부유물질 농도의 측정오차를 최소화하는 방법으로 사료된다.

• 한국재료학회지
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• 제28권11호
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• pp.627-632
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• 2018

Two dimensional(2D) crystals, composed of a single layer or a few atomic layers extracted from layered materials are attracting researchers' interest due to promising applications in the nanoelectromechanical systems. Worldwide researchers are preparing devices with suspended 2D materials to study their physical and electrical properties. However, during the fabrication process of 2D flakes on a target substrate, contamination occurs, which makes the measurement data less reliable. We propose a dry transfer method using poly-methyl methacrylate(PMMA) for the 2D flakes to transfer onto the targeted substrate. The PMMA is then removed from the device by an N-Methyl-2-pyrrolidone solution and a critical point dryer, which makes the suspended 2D flakes residue free. Our method provides a clean, reliable and controllable way of fabricating micrometer-sized suspended 2D nanosheets.

• 한국해양공학회지
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• 제24권1호
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• pp.99-105
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• 2010

The concentration and size analysis of in-situ suspended particulate material were measured using an optical instrument, LISST-100, in the bottom layer at the three inlets of the Seomjin River Estuary, mouth of Gwangyang bay, and Gwangyang bay-side of the Namhae Bridge. In the Seomjin river estuary and mouth of Gwangyang bay-side of the Namhae Bridge, the in-situ mean grain size of the suspended material changed from a uni-modal distribution with a dominant peak at a coarse fraction to a bi-modal distribution with a secondary peak at the finer particles. Seomjin River. The interactions between suspended particulate concentration and beam attenuation coefficient of suspended particulate matters depended on the supply of finer and coarser particles in the mouth of Gwangyang Bay and Seomjin River. So, interactions reflected difference of the concentration, mean size and sorting of suspended particulate matters. The difference of interaction showed dynamic behaviors to the resuspension and deflocculation processes increased river discharge. This showed that it may be possible to use the interactions between the suspended particle concentration and beam attenuation coefficient to monitor the temporal and spatial distributions of in-situ particles.

• 융합정보논문지
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• 제10권12호
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• pp.236-244
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• 2020

본 연구에서는 하천실험센터에서 부유 물질 실험을 수행하여 부유 물질의 거동 및 확산을 관찰하고 이를 입자분산모형을 통하여 그 이동을 구현하고자 하였다. 규사를 물과 믹서기를 이용하여 혼합한 후 실규모 크기의 실험수로에 인위적으로 투입하고 레이저부유사측정기(LISST)를 이용하여 부유 물질의 농도를 측정하였다. 실험에서 드론 이미지 및 부유사 측정기 관측 데이터와 입자 분산 모형을 통해 부유 물질의 거동을 모의하여 비교한 결과, 비교적 실험 결과가 구현이 잘 된 것을 확인할 수 있었다. 이를 통하여 입자 분산 모형의 적용성은 물론, 높은 강우량으로 인한 유량 발생 시 부유 물질 예측 활용성을 기대할 수 있게 되었다.

• 한국해양학회지
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• 제29권3호
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• pp.269-277
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• 1994

득량만의 20여개 지점에 대한 표층퇴적물 입도분포와 부유물총량을 해수에 의한 부유물이동 및 침전작용으로 해석하였다. 득량만의 표층퇴적물은 대부분 비대칭 단일 모드 입도분포를 보이며 거문고 욕지도간의 내대륙붕에 분포하는 뻘구역의 입도분포와 매우 유사하다. 입도분포자료의 분석에 의하면 득량만의 표층쾨적물은 황애쪽에서 동 진하는 부유이동 세립질퇴적물이 만으로 유입되어 퇴적된 것으로 보인다. 조립질퇴적 물의 함량과 계산에 의해 얻어진 조류의 유속(Lee, 1994)이 서로 유사한 공간적인 분 포를 나타내는 것으로 볼 때, 득량만내의 표층퇴적물은 강한 조류와 얕은 수심으로 인 하여 부유이동 및 침전작용을 거듭하는 것으로 판단된다. 이러한 작용이 퇴적물로 하 여 금 특징적인 비대칭 단일모드 입도분포를 가지게끔 하는 것으로 보인다. 또 이러한 작용은 부유물총량의 분포에도 큰 영향을 미치는 듯하다. 득량만에서 의 평균 부유물 농도는 표저층간의 차이는 하계가 동계에 비해 2배 정도크다. 이것은 득량만에서 하계 에는 수괴의 성층현상이 발달하는데 반해 동계에는 균질한 수괴가 발달하는데 원인이 있는 것으로 판단된다. 부유물질의 양적인 분포와 계절적인 변동특성을 종합해서 볼 때 득량만내의 부유물 총량을 크게 좌우하는 요인은 유속 및 성층변동과 같은 수괴의 물리적인 특성, 수심과 같은 지형적 특성 그리고 부분적으로 육지로부터 의 부유물질 의 공급등이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.87-88
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• 2006

It is needed several large reservoirs and long time in order to remove suspended solid like steel fines and iron oxide at steel making factory. If removing rate of suspended solid in rolling coolant is improved, the productivity of working process can be increased and the area of reservoir can be reduced. Pre-treatment to add extra magnetization of suspended solid was studied Iron hydroxide and electrolytic dissociation were used for pretreatment. High gradient magnetic separation (HGMS) system was used for removing of magnetized suspended solid. Removing ratio showed over than 99% in the coolant containing magnetic fines. Magnetic properties of suspended solid were investigated after mixed with Al2(SO2)3 and organic flocculant by using electrochemical treatment.

• Journal of the korean society of oceanography
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• 제37권3호
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• pp.178-186
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• 2002

The mud deposit located to the south of Cheju Island, the East China Sea, is characterized by an upwelling system or, on occasions, a combined upwelling-downwelling system. The water mass here is associated with relatively high suspended matter concentrations. In the present study, a vertical I-D model is used to undertake numerical experiments for evaluating the upwelling and downwelling effects on the suspended particulate matter distribution patterns within the water column. The results show that: (1) because the upwelling or downwelling velocity tends to be of the same order of magnitude as the settling velocity of suspended particles, a number of different patterns of suspended matter concentration distribution are possible, depending on the relative importance of the velocities; (2) the presence of upwelling can enhance the suspended particulate matter concentration; and (3) in an upwelling-downwelling system, maximum concentrations may or may not lie in the middle of the water column, depending on, once again, the interrelationships between the opwelling/downwelling velocities and the settling velocity. Hence, the physical processes associated with upwelling/downwelling appear to be relevant to the suspended material distribution over shelf mud areas.

• 한국항만학회지
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• 제14권4호
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• pp.451-461
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• 2000

The design and maintenance of navigation channel and water facilities of an harbor which is located at the mouth of river or at the estuary area are difficult due to the complexity of estuarial water and sediment circulation. Effects of deepening navigable waterways, of changing coastline configurations, or of discharging dredged material to the open sea are necessary to be investigated and predicted in terms of water quality and possible physical changes to the coastal environment. A borad analysis of the transport mechanism in the estuary area was made in terms of sediment property, falling velocity, concentration and flow characteristics. In order to simulate the transport processes, a two-dimensional finite element model is developed, which includes erosion, transport and deposition mechanism of suspended sediments. Galerkin’s weighted residual method is used to solve the transient convection-diffusion equation. The fluid domain is subdivided into a series of triangular elements in which a quadratic approximation is made for suspended sediment concentration. Model could deal with a continuous aggregation by stipulating the settling velocity of the flocs in each element. The model provides suspended sediment concentration, bed shear stress, erosion versus deposition rate and bed profile at the given time step.

• 한국수산과학회지
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• 제52권1호
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• pp.74-80
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• 2019

Nonylphenol is an endocrine-disrupting chemical that is the degradation product of the nonionic surfactants nonylphenol ethoxylates. To understand the contamination and behavioral characteristics of nonylphenol, we measured the nonylphenol concentrations in surface water in the lower reaches of the Suyeong River, Korea. The results were used to estimate the material balance. The target area was divided into three regions to estimate the material balance of nonylphenol. In region 1, in flux of the dissolved nonylphenol was 282.3 g/day and the nonylphenol influx in particulate suspended solids was 1,582.8 g/day. The dissolved nonylphenol outflow discharged toward region 2 was 192.5 g/day, while the adsorption to particulate suspended solids was 89.8 g/day. Within the particulate suspended solids, the outflow to region 2 was 1,250.0 g/day, while the estimated amount settling in the sediments was 422.7 g/day. The adsorption of dissolved nonylphenol to the particulate suspended solids in regions 1 and 2 was 31.8% and 54.9%, respectively. In region 3, the desorption rate was 8.8%.

• 한국환경과학회지
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• 제20권12호
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• pp.1533-1540
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• 2011

This study was conducted to identify the sedimentation quantity and settling velocity, sediment fundamental data that an important position of water quality management of Seston, POC, PP and PN in Nakdong river basin using a sediment traps to collect suspended material pollutants. Nakdong river basin is that average sedimentation quantity of seston, POC, PP and PN were 124~1,125 g/$m^2$/d, 2,963~25,072, 26~347, 445~2,184 mg/$m^2$/d, respectively. Settling velocity of Seston, POC, PP and PN were 17.0, 35.5, 8.7, 2.4 m/d. It was appeared that various results according to the river flow, weather and other environmental factors. There was no significant correlation, each suspended material pollutants. Sedimentation rates are likely to be overestimated because the flow is not considered to resuspended materials. Therefore diversification through continued monitoring is needed to be analyzed.