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Band Dispersion in Lab-on-a chip for protein separation
Jaesool Shim,Prashanta Dutta,Cornelius F. Ivory 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.10
Ampholyte based isoelectric focusing (IEF) simulation was conducted to study dispersion of proteins in a horse shoe microchannel. Four model proteins (pls= 6.49, 7.1, 7.93 and 8.6) are focused in a 1 ㎝ long horse shoe channel under an electric field of 300 V/㎝. The pH gradient is formed in the presence of 25 biprotic carrier ampholytes (?pK = 3.0) within a pH range of 6 to 9. The proteins are focused at 380 sec in a nominal electric field of 300 V/㎝. Our numerical results show that the band dispersions of a protein are large during the gradient formation stage, but the dispersions are significantly reduced when the double peaks start to merge. This rearrangement of spreading band isvery unique compared to linear electrokinetic phenomena (capillary zone electrophoresis) and is independent of channel position and channel shape. Hence, one can perform IEF and other self-sharpening electrokinetic methods, such as, isotachophoresis (ITP), in complex geometries without incorporating hyperturns.
Dispersion of protein bands in a horseshoe microchannel during IEF
Shim, Jaesool,Dutta, Prashanta,Ivory, Cornelius F. WILEY-VCH Verlag 2009 Electrophoresis Vol.30 No.5
<P>Ampholyte-based IEF is simulated for a 2-D horseshoe microchannel. The IEF model takes into account ionic-strength-dependent mobility corrections for both proteins and ampholytes. The Debye–Huckel–Henry model is employed to correct the protein mobilities and the Onsager–Debye–Huckel model is used to obtain effective mobilities of ampholytes from their limiting mobility. IEF simulations are conducted in the presence of 25 ampholytes (ΔpK=3.0) within a pH range of 6–9 under an electric field of 300 V/cm and using four proteins (pIs=6.49, 7.1, 7.93 and 8.6) focused in a 1-cm-long microchannel. The numerical results show that the concentrations of proteins and ampholytes are different when mobility corrections are considered but that the focusing positions remain the same regardless of mobility corrections. Our results also demonstrate that, unlike linear electrophoresis in which the bands deform significantly as they traverse a bend, during the transient portion of IEF racecourse dispersion is mitigated by focusing and, at focused-state, those bands that focus in the bend show no radial concentration dependence, i.e. they completely recover from racecourse dispersion, even within a tight turn.</P>
The Problems of Korean School Science Curriculum and Suggestions for a New Direction
Kwon, Jaesool 한국과학교육학회 2001 한국과학교육학회지 Vol.21 No.5
The Korean national curriculum has changed several times. The curriculum reforms could be divided into three periods. This study reviewed briefly the history of Korean science curriculum reforms, and then treated of the problems the Koreas science curriculum has. Lastly, some suggestions were proposed for the improvement of the Korean science curriculum as a new direction for the future.
Bhargav Akkinepally,Jaesool Shim 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
The world is moving towards the renewables and Li-batteries play a vital role in that green future. Owing to the safety issues of liquid electrolytes, solid electrolytes are in demand to replace the already existing Li-ion battery infrastructure. This necessitates the research efforts into discovering suitable solid electrolytes which have higher ionic conductivities. As the process of screening of electrolytes by trial and error is time consuming and resource intensive, thereby demands the development of appropriate machine learning algorithms. In this work, we focus on developing a novel machine learning algorithm to predict the ionic conductivity of Li Super Ionic Conductors (LiSICON). The elemental features derived from the unit cell information and the atomic properties of the elements of 40 LiSICON compounds. The logistic regression model we developed is capable of classifying in which category the compound falls into from either good, average or bad with an accuracy of over 88 %. The test data results are validated with the molecular dynamics simulations. These findings exhibit the benefits of using such a tool in the preliminary screening of potential solid electrolytes with the existing data which helps in focusing only on the promising candidates thereby reducing the time consumption for experimentalists.
Opto-electrokinetic 효과에 의한 Toroidal Microvortex 형성에 관한 수치해석적 연구
김동(Dong Kim),심재술(Jaesool Shim),김경천(Kyung Chun Kim) 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.12
In this study, the formation of a toroidal microvortex by optoelectrokinetic effect was numerically simulated using COMSOL v4.2a multiphysics software. AC voltage was applied to the two parallel electrodes in a microchannel to generate temperature gradient in the fluids. In addition to the AC electrothermal (ACET) effect, local heating by a laser illumination was also considered. Numerical simulations were conducted for dielectric fluids. The toroidal microvortex induced by the optoelectrokinetic effect shows that two counter-rotating vortices are produced above the bottom electrodes. Fluid motions in the middle of bottom boundary are cancelled out by flows in opposite directions and consequently producing stagnation. It is expected that micro/nano particles are deposited in bottom electrode. Local heating enhanced the intensity of microvortex substantially due to the additional temperature gradient, it was confirmed that the ACET effect with laser illumination can be used for rapid concentration of micro/nano particles in the spot area.
The Korean Elementary Students' Conceptions of the Simple Electric Circuit
Seo, Sangoh,Kwon, Jaesool 한국과학교육학회 2002 한국과학교육학회지 Vol.22 No.5
The purpose of this study was to investigate students' conceptions of the simple electric circuit using a battery and a bulb. 19 fourth grade students from a rural elementary school in Korea participated in this study. Data on the children's understandings of electric circuit were collected through three sources; prediction test, drawing tests and individual interviews. The prediction test were paper and pencil composed of 10 problems, prediction whether bulbs in 10 simple circuit diagrams would light. For each prediction, the children were asked to provide a written explanation of their thinking. The drawing tests consisted of 6 problems. One was to draw the inside of the bulb base, and the others were to make the wire connections between a battery and a bulb in the diagrams, to light the bulb. The interviews were conducted with seven children who showed differing degrees of understanding. No student was aware of the wire connections inside the bulb base. Many students stated whether the bulb would light or not, according to the tip of the bulb contacting the positive battery terminal and an end of wire contacting the negative battery terminal. Most of them thought that the tip of the bulb should contact the positive battery terminal, so that the bulb would light. In short, students did not use a scientific conceptions of electric current to predict and explain the electric circuit.