• Proceedings of the Korean Biophysical Society Conference
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• 1997.07a
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• pp.11-12
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• 1997

A concept that extracellular ATP plays a role as a neurotransmitter is now widely accepted. ATP released from nerve terminals transmits both excitatory and inhibitory signals to postsynaptic neurons, muscle cells, and non-excitable cells. ATP-activated channels are effectors that convert the binding of ATP into the opening of ion channel pores in postsynaptic membrane.(omitted)

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.65-72
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• 2007

The purpose of this study was to examine the 7th national science curriculum (chemistry domain) regarding the meanings of ‘mulgil' (Korean), the particulate nature of matter, and the state of matter. It was found that the term of ‘mulgil' was being used vaguely as representing material, matter, or substance without clear definition. This was problematic by reason that it could hinder students from having the concept of substance. Regarding the particulate nature of matter, molecule was introduced as a basic unit of matter at grade 7, prior to atom and ion, which were introduced at grade 9 and 10, respectively. It is necessary to reconsider the sequence of each particle concept to provide students with more consistent and comprehensive understanding of structure of matter. In the case of change of state, key concepts such as conservation of matter or reversibility were omitted in the curriculum document, and explanations based on various aspects of particles were somewhat insufficient. The concept of matter is fundamental to chemistry, and we must recognize it as a concept that needs to be taught clearly. Implications for curriculum revision were discussed.

• Polymer(Korea)
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• v.26 no.6
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• pp.785-791
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• 2002

The effect of the supercritical carbon dioxide (sc$CO_2$) on ion-conductive behaviors for polyether electrolytes based on, both poly (ethylene oxide) (PEO) and poly [oligo (oxyethylene glycol) methacrylate] (PMEO) with lithium triflate, LiCF$_3$SO$_3$, has been investigated. In particular, the present research is a new concept for improving the ionic conductivity of polyether electrolytes. The maximum ionic conductivity ($\sigma$$_{max}$) at room temperature of the PEO electrolyte was more than 100 times higher, and the $\sigma$$_{max}$ at 9$0^{\circ}C$ of the PMEO electrolyte was 30 times improved by the se$CO_2$ treatment, respectively. It was revealed that the penetration of $CO_2$ molecules into the polymer matrix causes the increase of carrier ions by ion-dispersion effect and the decrease of glass transition temperature (T$_{g}$) by plasticizing effect that results in the improvement of the ion transport behaviors.viors.

• Journal of the Korean Chemical Society
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• v.60 no.5
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• pp.362-373
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• 2016

In this study, ionic compound in the science textbooks developed under the 2009 revised national curriculum were analyzed in terms of the scientific concept and model description and the student understanding through the questionnaires. Analysis of textbooks was performed for science2 of middle school and chemistry I & II of high school. Questionnaire was carried out with 194 students including middle school 2nd grade and high school 1st-3rd grade. The results are as follows: First, as a result of analysis of textbooks, scientific concepts and models used to explain the ionic compound showed differences depending on the types of textbooks. In addition, scientific models were provided with or without explanation for the scientific concepts. Second, analysis of the questionnaire showed that students didn’t properly understood scientific concepts and models in the ion formation, stoichiometric ratio between ions.

• Journal of the Korean Chemical Society
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• v.60 no.1
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• pp.48-58
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• 2016

This study was to investigate the types of middle school students’ conceptual change on electrolyte and ion. Data were collected by pre- and post- exams of 9th grade students’ conceptions of electrolyte and ion, and by semi-structured interviews with nine students served as case representatives who participated in the study. All interviews were transcribed, analyzed and classified by conceptual change according to the responses of the students. The results are as follows: First, students’ ion conceptual change was classified into four types; simple conception to sophisticated conception, incomplete conception to scientific conception, misconception to confused conception, and misconception to misconception. Most students had difficulty in understanding of the concepts of ion in pre- and post-class, and they failed to distinguish between atom and subatomic particles precisely. Second, students’ conceptual change of electrolyte was also classified into the following four types; partially scientific conception to sophisticated conception, misconception to partial misconception, incomplete conception to incomplete conception and misconception to misconception. The study found that students had difficulty distinguishing the difference between electrolytes and nonelectrolytes. Third, students also had difficulty understanding the concepts on particles because they learned the ‘electrolyte and ion’ unit so quickly in the second semester of 9th grade in order to fill in the academic reports for applying high schools. Furthermore, some suggestions were made based on the results for understanding scientific concepts on particles.

• Journal of the Korean Society of Safety
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• v.31 no.5
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• pp.22-27
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• 2016

The Electrostatic Charge Prevention Technology is a core factor that highly influences the yield of Ultra High Resolution Flat Panel Display and high-integrated semiconductor manufacturing processes. The corona or x-ray ionizations are commonly used in order to eliminate static charges during manufacturing processes. To develop such a revolutionary x-ray ionizer that is free of x-ray radiation and has function to control the volume of ion formation simultaneously is a goal of this research and it absolutely overcomes the current risks of x-ray ionization. Under the International Commission on Radiological Protection, it must have a leakage radiation level that should be lower than a recommended level that is $1{\mu}Sv/hour$. In this research, the new generation of x-ray ionizer can easily control both the volume of ion formation and the leakage radiation level at the same time. In the research, the test constraints were set and the descriptions are as below; First, In order not to leak x-ray radiation while testing, the shielding box was fully installed around the test equipment area. Second, Implement the metallic Ring Electrode along a tube window and applied zero to ${\pm}8kV$ with respect to manage the positive and negative ions formation. Lastly, the ion duty ratio was able to be controlled in different test set-ups along with a free x-ray leakage through the metallic Ring Electrode. In the result of experiment, the maximum x-ray radiation leakage was $0.2{\mu}Sv/h$. These outcome is lower than the ICRP 103 recommended value, which is $1{\mu}Sv/h$. When applying voltage to the metallic ring electrode, the positive decay time was 2.18s at the distance of 300 mm and its slope was 0.272. In addition, the negative decay time was 2.1s at the distance of 300 mm and its slope was 0.262. At the distance of 200 mm, the positive decay time was 2.29s and its slope was 0.286. The negative decay time was 2.35s and its slope was 0.293. At the distance of 100 mm, the positive decay time was 2.71s and its slope was 0.338. The negative decay time was 3.07s and its slope was 0.383. According to these research, the observation was shown that these new concept of ionizer is able to minimize the leakage radiation level and to control the positive and negative ion duty ratio while ionization.

• Journal of the Korean Chemical Society
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• v.33 no.6
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• pp.588-595
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• 1989

Log K, ${\Delta}$H and ${\Delta}$S for the complexation of $La^{3+},\;Ce^{3+}$ and $Eu^{3+}$with various multidentate ligand containing crown ether, diaza crown ether and diamine ether have been determined in methanol and acetonitril solutions at $25^{\circ}C$ by solution calorimetric titration method. The greater stability constant of $La^{3+}$-15C5 than those of 18C6 diaza [2.2] in methanol are discussed in terms of the size of metal ion and the ligand cavity and of metal ion solvation. The stabilities of $Ce^{3+}$ and $La^{3+}$ ion complexes with a various multidentate ligand in acetonitril are in the order of (diamine ether)<18C6<15C5$Ce^{3+}$, $La^{3+}$ and $Eu^{3+}$-diaza [2.2] complexes in acetonitril are increased with the following order: $Eu^{3+}$ < $La^{3+}$ < $Ce^{3+}$, that is increasing order of the optimum size and of the charge density of metal ion.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.53-58
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• 2016

Because a progressive tax of home electricity rates is charged and a continuous rise of industrial electricity rates is expected in order to solve the global warming, the high oil prices and the serious power shortage problem, the efforts to apply the energy storage systems which can significantly improve the energy usage efficiency to the smart grid are trying newly. In this study, characteristics of the secondary battery which can be used as energy storage devices, the structure and operation principle of a lithium-ion battery, and the concept of energy storage systems are research and analyzed. In addition, in this paper, the base technologies which are required to apply to the energy storage system to electric power system are established by studying about installation location and application methodology of energy storage system to electric power system.

• Journal of Electrochemical Science and Technology
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• v.5 no.2
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• pp.37-44
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• 2014

The $Li-O_2$ battery has been attracting much attention recently, due to its very high theoretical capacity compared with Li-ion chemistries. Nevertheless, several studies within the last few years revealed that Li-ion derived electrolytes based on alkyl carbonate solvents, which have been commonly used in the last 27 years, are irreversibly consumed at the $O_2$ electrode. Accordingly, more stable electrolytes are required capable to operate with both the Li metal anode and the $O_2$ cathode. Thus, due to their favorable properties such as non volatility, chemical inertia, and favorable behavior toward the Li metal electrode, ionic liquid-based electrolytes have gathered increasing attention from the scientific community for its application in $Li-O_2$ batteries. However, the scale-up of Li-$O_2$ technology to real application requires solving the mass transport limitation, especially for supplying oxygen to the cathode. Hence, the 'LABOHR' project proposes the introduction of a flooded cathode configuration and the circulation of the electrolyte, which is then used as an oxygen carrier from an external $O_2$ harvesting device to the cathode for freeing the system from diffusion limitation.

• Journal of Astronomy and Space Sciences
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• v.35 no.1
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• pp.31-37
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• 2018

Pc1 pulsations are geomagnetic fluctuations in the frequency range of 0.2 to 5 Hz. There have been several observations of Pc1 pulsations in low earth orbit by MAGSAT, DE-2, Viking, Freja, CHAMP, and SWARM satellites. However, there has been a clear limitation in resolving the spatial and temporal variations of the pulsation by using a single-point observation by a single satellite. To overcome such limitations of previous observations, a new space mission was recently initiated, using the concept of multi-satellites, named the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE). The SNIPE mission consists of four nanosatellites (~10 kg), which will be launched into a polar orbit at an altitude of 600 km (TBD) in 2020. Four satellites will be deployed in orbit, and the distances between each satellite will be controlled from 10 to 1,000 km by a high-end formation-flying algorithm. One of the possible science targets of the SNIPE mission is observing electromagnetic ion cyclotron (EMIC) waves. In this paper, we report on examples of observations, showing the limitations of previous EMIC observations in low earth orbit, and suggest possibilities to overcome those limitations through a new mission.