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김기윤(G.Y. Kim),김보현(B.H. Kim),김윤년(Y.N. Kim),이용구(Y.G. Lee),허윤석(Y.S.Heo) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Aortic dissection is the most dangerousheart disease. It can cause aortic rupture in any time with treatment or without treatment. Thus patients must manage therisk factors. To control the factor like blood pressure, we need to set a threshold value for the safe zone for each patient.This important threshold can be obtained from analysis of blood flow. In this study, the clinical data was used to obtainthe 3D model of aortic dissection. The fluid flow simulation was done by using comsol multiphysics. We have preformed analysisin laminar fluid condition with inlet pressure. Velocity was analyzed along the 3d model. As we have expected, the velocitywas increased in the point of dissection was occurred. However, the increment of velocity was very large in the criticalarea.
김민영(M.Y. Kim),이용구(Y.G Lee),김윤년(Y.N. Kim),남창욱(C.W Nam),허윤석(Y.S.Heo) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Aortic dissection is a medical emergency situation requiring quick and proper treatments, otherwise patient can suddenly lead to death as a result of rupture of the aorta. The rupture can be triggered by many factors such as blood pressure, velocity, viscosity etc. and it is critical for patients to manage the internal and external factors acting on the blood vessels before the rupture begins. To control the factor like blood pressure, we need to set a threshold value for the safe zone for each patient to provide proper treatment guidelines. This important threshold can be obtained from the analysis of blood flow in the 3D model of aortic dissection. In this study, we analyzed CT images obtained from three patients who had three different type of the aortic dissection, respectively. The fluid flow simulations were done by using COMSOL Multiphysics. The results from the computational simulation are able to explain the blood flow characteristics and are well accordance with the expectation from the patient’s condition and types of aortic dissection.
노즐 모양의 미세 유체 채널을 이용한 크기에 따른 입자 분리 연구
이성한(S.H. Lee),곽봉섭(B.S. Kwak),허윤석(Y.S. Heo) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Recently the research on the particle separation is going along various method and using in a biomedical application. I have demonstrated the separation of particle using the force balance on the size different micro-particles between inertial and viscous force in a nozzle shape of microchannel. If fluid flow rate maintain high velocity(0.01~1㎧), the Reynolds number can attain very high field and ignored inertial force appear compared with viscous force. And Stokes number is relative to the radius of particle other things being equal, so I can forecast the movement of different size particles and convinced these by simulation and experiment. This technique requires only hydraulic force and has high-throughput due to the high flow rate. Thus this research is useful in the case of using a variety of size cells including circulating tumor cells(CTC) instead of particle.
Microfluidic Chip 유동특성을 이용한 PDMS 화학적 식각 및 상처 모델 구현
김민영(M.Y. Kim),정순우(S.W. Jung),이태재(T.J. Lee),허윤석(Y.S. Heo) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
Lab on a chip using microfluidic has many advantages in comparison with existing in vitro experiment. It can make more in vivo like experiment by mimicking human internal environment. Because microfluidic has many advantages, many researcher mimic wound healing mechanisms inside microfluidic chips. But mostly research has conduct an experiment on flat channels without considered wounds depth. Wounds depth has a great influence upon the cell migration, when wounds healing. So in this research, I develop in vivo like wound healing chip having depth by chemical etching using laminar flow.
수축과 이완작용이 가미된 치과용 인상재 믹싱팁의 혼합 효율 향상 연구
김민수(M.S. Kim),양소혜(S.H. Yang),허윤석(Y.S. Heo) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
Mixing tip has many advantage such as minimizing the entry of bubble and mix uniform. However, impression materials remain in the mixing tip because of its disposability. We add esophagus peristalsis on mixing tip and adjusted the location of twist. The form was simulated by COMSOL before the experiment and modeling many kinds of mixing tip by Solid Works to print out using a 3D printer. Then, using Image J confirm degree of mixing uniformity. The result show that the ratio of 2:8 is better than 5:5 in mixing efficiency. With peristalsis effect, we can reduce impression materials by making mixing tip more shorter than existing. We expect that this result can be applied to a micro-fluidic mixing study.
45°의 확장과 축소 배열의 마이크로 채널을 이용한 크기에 따른 입자 분리 연구
곽봉섭(B.S. Kwak),이성한(S.H. Lee),허윤석(Y.S. Heo) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
With the recent development of the micro-particle separation in microfluidic system it has been applied in various fields. We developed a new microfluidic device which 100 repeated 45° angled expansion structures and contraction channels for particle separation with high-throughput. This micro channel use the combination of the momentum change-induced inertial force and the inertial lift force acting on micro particles according to particle Reynolds number. 2μm, 6μm, 13μm diameter particles were used to this study. 13μm particles focus on the centerline of channel and 2μm and 6μm particles move toward both side wall of micro channel in 260μL/min of flow rate.
혈중 종양 세포 분리 Chip을 이용한 미세 유체 채널 내 입자 유동 연구
김정아(J.A. Kim),김태성(T.S. Kim),조치흠(C.H. Cho),허윤석(Y.S. Heo) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
Circulating tumor cells (CTCs) present in the bloodstream of cancer patients. CTCs provide a potentially accessible source for detection, characterization, and monitoring of nonhematological cancers. We demonstrate the effectiveness of the CTC-Chip for the isolation of ovarian cancer cells by adapting the herringbone-chip (HB-Chip). The motion of the particles on the HB chip are simulated by a unique combination of buoyant, gravitational forces, and helical flows with computational modeling. The real motion of cells are demonstrated by applying polystylene bead and ovarian cancer cells into the microfabricated HB chip. The experimental results from beads and cells are well accordance with the simulated ones, as previous reported by Toner group. Thus, we expect that these modeling and experimental skills will play key roles in the clinical applications on CTC isolation as well as the basic research on characterization of CTCs under flow.