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오늘 본 자료
김덕종,김재윤,박상진,허필우,윤의수,Kim, Deok-Jong,Kim, Jae-Yun,Park, Sang-Jin,Heo, Pil-U,Yun, Ui-Su 한국기계연구원 2003 硏究論文集 Vol.33 No.-
In this work, thermal design of a PCR chip for LOC is systematically conducted. From the numerical simulation of a PCR chip based on the finite volume method, how to control the average temperature of a PCR chip and the temperature difference between the denaturation zone and the annealing zone is presented. The average temperature is shown to be controlled by adjusting heat input and a cooler as well as a heater is shown to be necessary to obtain three individual temperature zones for polymerase chain reaction. To reduce the time required, a heat sink for the cooler is not included in the calculation domain for the PCR chip and heat sink design is conducted separately by using a compact modeling method, the porous medium approach.
다공성 매질과 비투과성 벽면 사이의 경계면에 대한 열적 경계 조건
김덕종,김성진,Kim, Deok-Jong,Kim, Seong-Jin 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.12
The present work investigates a heat transfer phenomenon at the interface between a porous medium and an impermeable wall. In an effort to appropriately describe the heat transfer phenomenon at the interface, the heat transfer at the interface between the microchannel heat sink, which is an ideally organized porous medium, and the finite-thickness substrate is examined. From the examination, it is clarified that the he heat flux distribution at the interface is not uniform for the impermeable wall with finite thickness. On the other hand, the first approach, based on the energy balance for the representative elementary volume in the porous medium, is physically reason able. When the first approach is applied to the thermal boundary condition, and additional boundary condition based on the local thermal equilibrium assumption at the interface is used. This additional boundary condition is applicable except for the very th in impermeable wall. Hence, for practical situations, the first approach in combination with the local thermal equilibrium assumption at the interface is suggested as an appropriate thermal boundary condition. In order to confirm our suggestion, convective flows both in a microchannel heat sink and in a sintered porous channel subject to a constant heat flux condition are analyzed. The analytically obtained thermal resistance of the microchannel heat sink and the numerically obtained overall Nusselt number for the sintered porous channel are shown to be in close agreement with available experimental results when our suggestion for the thermal boundary conditions is applied.
초등학교 교사들의 학습부진학생 지도 경험에 대한 인식탐색-코로나19 상황 비대면 수업을 중심으로-
김덕종(Deok-Jong KIM),황미영(Mi-Young HWANG),원효헌(Hyo-Heon WON) 한국수산해양교육학회 2021 水産海洋敎育硏究 Vol.33 No.2
The purpose of this study is to explore the capacity of teachers that can help the academic achievement and emotions of underachiever students, which are increasing due to online classes of COVID-19, and to explore the direction in which school education should go for underachiever students. Seven elementary school teachers were interviewed in this study and the results were analyzed using the NVivo12 program. As a result, 3 subjects, 13 upper categories, and 45 subcategories were derived. Each subject was categorized into the impact of online class, the difficulty of online class and management of underachieving students. The teachers who participated in this study generally recognized the importance and necessity of education for underachievers, but the difficulties in managing students, lack of competence and guidance of parents, and class difficulties and problems in content production, excessive workload, widened learning gaps, changes in students life and learning habits, parents non-cooperation, and not knowing how to teach various underachiever students were pointed out. However, teachers were trying to improve their own problems, such as listening to related training and coaching after school. In addition, it showed that he was thinking and contemplating various areas such as government support necessary for students with poor learning, required qualities of external experts, coaching method and mind education necessary for teachers, and parental education. Based on the research results, suggestions for consideration for underachieving students are as follows. First, institutional support should be provided so that teachers, who can be said to be the subject of student guidance from the teachers perspective, can manage underachiever students well. Second, from the perspective of students, support from outside experts who can replace the vacant positions of parents who are difficult to manage their children due to busy work life to maintain a livelihood, compulsory parental education, and support for external facilities and programs.
허필우(Pil-Woo Heo),김덕종(Deok-Jong Kim),김재윤(Jae-Yun Kim),박상진(Sang-Jin Park),윤의수(Eui-Soo Yun),고광식(Kwang-Sik Koh) 한국유체기계학회 2003 유체기계 연구개발 발표회 논문집 Vol.- No.-
Micromixer plays an important role in Bio-MEMS or μ-TAS. Mixing is generally generated by turbulence and interdiffusion of two fluids. Because of low Reynolds number(Re << 2000) in μ-channel, it is difficult to generate turbulence, so mixing mainly depends on interdiffusion. Thus long channel distance is required to mix two different fluids. To reduce the channel length required for mixing, we propose the a new active μ-mixer that two fluids are effectively mixed in μ-channel by the ultrasonic wave which is generated by PZT. The ultrasonic wave is radiated into a chamber in the cross-section directional direction to interface with the two fluids. The two fluids are positioned one on top of the other. Mixing state is measured by the changing of color due to the reaction of NaOH and phenolphtalein.