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쏠림 체험에 대한 부주의한 해석과 관성력의 이른 도입에 대한 비판적 고찰: 뉴턴 역학의 관점에서
정용욱,송진웅 한국물리학회 2011 새물리 Vol.61 No.8
Two interpretations of the inertial force are frequently found in texts and among students conceptions. In one, the inertial force is experienced through a contraction or relaxation of the human body;in the other, the inertial force is directly related to inertia. In this study, we discuss the problem with the interpretations based on analysis of experience with the contraction or the relaxation of the body in everyday life from the perspective of Newtonian mechanics. We argue that the inertia force is unrelated to contraction or relaxation because the force causes uniform acceleration of the elements of the body. On the contrary, by illustrating that the experience can be explained by a contact force and inertia, we argue that the inertia force is not directly related to inertia through the body's experience. In addition, we examine the appropriateness of explanations of the inertial force found in the textbook. Finally, we discuss the validity of introducing the inertial force in the high-school physics curriculum. 관성력이 신체의 쏠림을 통해 느낄 수 있는 힘이라는 해석과 관성력과관성이 직접적으로 관련된다는 해석은 학습자의 사고과정과 교재로부터자주 발견된다. 본 연구는 일상생활에서의 신체의 쏠림 체험을뉴턴역학의 입장에서 분석하여 두 해석이 갖는 문제점을 살펴보았다. 이를 위해 관성력이 신체의 각 부분에 균일한 가속도를 유발하므로신체의 변형과 관련되지 않음을 보였다. 대신에 가속상황에서의 신체의변형이 접촉력과 관성 개념으로 설명된다는 것을 예증함으로써 관성력과관성이 쏠림체험을 통해 직접적으로 관련되지 않음을 보였다. 이러한결과에 기초하여 교재에서 발견되는 쏠림 상황에 대한 설명들의 적절성을검토하였다. 끝으로 고등학교 교과과정에서 관성력을 도입하는 것의교육적 타당성에 대해 논의하였다.
마이크로 채널에서 관성력을 이용한 혈중 종양 세포의 크기에 상응하는 입자 분리 연구
곽봉섭(Bongseop Kwak),이성한(Sung Han Lee),허윤석(Yun Seok Heo) 한국가시화정보학회 2016 한국가시화정보학회 학술발표대회 논문집 Vol.2016 No.12
It is well known that CTCs(Circulating Tumor Cells) separation is critical for cancer diagnoses and therapy. 1 - 1,000 CTCs exist in 1mL volume of cancer patient blood while 5 × 10<SUP>9</SUP> erythrocytes and 4 × 10<SUP>6</SUP> leukocytes exist in thereto. Because of the rarity of CTCs, CTCs enrichment process is necessary before the detection of them. We used the particles corresponding the size and density of cells and achieved particle separation with high-throughput in micro channel. The inertial forces(inertial lift force and momentum change induced inertial force) are used to particle separation at particular flow rate in this microchannel. We expand that this microchannel can apply various cell separation.
확장/축소 배열의 마이크로 채널의 관성력을 이용한 적혈구와 순환 종양 세포 분리 연구
이성한(Sung Han Lee),Thapa Mukesh,박민규(Min Gyu Park),채혜송(Hyeon Song Chae),허윤석(Y.S. Heo) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
Recently, particle separation studies have been conducted in micro systems. Particularly, the method of separating particles by a hydrodynamic method requires no additional external force. It is also possible to separate cells from microfluidics systems using cells instead of particles. We have conducted a study to isolate circulating tumor cells from red blood cells. Because circulating tumor cells are present in very small amounts compared to blood cells, the enrichment step is required for effective detection. We designed expansion/contraction array microchannel, which separates circulating tumor cells(MCF-7) from red blood cells by inertial force. This microchannels have experimentally proven that cells can be separated with high throughput and high efficiency.
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.
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.
박용철(Yong-Chul Park),김봉수(Bong-Soo Kim),김경련(Kyoung-Rean Kim),우종섭(Jong-Sub Wu) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
In HANARO, a multi-purpose research reactor of 30 MWth, the primary cooling system is composed of two heat exchangers, two pumps, piping including valves and instruments for cooling a nuclear fission heat during a normal operation. The flywheel attached to each pump motor shaft provides inertia forces to ensure a slow decrease in coolant flow in order to prevent fuel damage as a result of a loss of power to the pump motor. During operation at normal speed, the flywheel has sufficient kinetic energy to produce high-energy missiles and excessive vibration of the reactor coolant pump assembly if the flywheel should fail. Overspeed of the pump rotor assembly during a transient increases both the potential energy for failure and the kinetic energy of the flywheel. The safety consequences could be significant because of possible damage to the primary cooling system, the containment, or other equipment or systems important to safety. This paper describes the structural integrity of the flywheel including the test requirements, test methods and results. It was confirmed through the test results that the structural integrity of each flywheel is maintained in safety.