• 한국초전도ㆍ저온공학회논문지
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• 제16권1호
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• pp.32-35
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• 2014

Recently, many researches on the system of superconducting power supply and superconducting magnetic energy storage (SMES) using high temperature superconducting (HTS) tapes has been progressed. Those kinds of superconducting devices use the heater trigger switches that have a control delay problem at moments of heating up and cooling down. One way to reduce the time delay is using a different HTS tape at trigger part. For example, HTS tape having lower critical temperature can reduce time delay of heating up and heating down stage for heater trigger operation. This paper deals with resistances joint with different kinds of HTS tapes which have different properties to verify usefulness of the suggested method. Three kinds of commercial HTS tapes with different specifications are selected as samples and two kinds of solders are used for comparison. Joint is performed with temperature and pressure controllable joint machine and the joint characteristics are analyzed under the repeatable conditions.

• 접착 및 계면
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• 제11권1호
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• pp.26-34
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• 2010

가열에 의해 해체가 가능한 열적특성을 갖는 폴리우레탄 접착제를 합성하였으며 열팽창비드를 혼합하여 해체성 접착제를 제조하였다. Dynamic mechanical thermal analyzer (DMA)를 사용하여 폴리우레탄의 열적특성을 확인하였고 접착강도와 열팽창비드의 함량, 가열 trigger의 종류와 처리조건에 따른 해체특성을 연구하였다. 열풍과 microwave 처리에 의해서 해체성 폴리우레탄 접착제의 부피팽창에 따른 접착된 시편의 해체가 가능하였으며, 열팽창비드의 함량이 증가될수록 접착된 피착재가 더 쉽게 분리되었다. 해체성 접착제에서 접착력과 해체특성 모두를 만족시킬 수 있는 가장 적합한 열팽창비드 사용량은 40%이였으며, 가열 trigger로 열풍을 사용한 경우에는 $160^{\circ}C$, 30 min의 조건에서, 가열 trigger로 microwave를 사용한 경우에는 조사시간 4 min의 조건에서 접착되어 있는 피착재가 완전히 해체되었다.

• Journal of Power Electronics
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• 제12권6호
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• pp.974-981
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• 2012

A FPGA based delta modulated single phase matrix converter has been developed that may be used in both cyclo-converters and cyclo-inverters. This converter is ideal for variable speed electrical drives, induction heating, fluorescent lighting, ballasts and high frequency power supplies. The peripheral input-output and FPGA interfacing have been developed through Xilinx 9.2i, to generate delta modulated trigger pulses for the converter. The controller has been relieved of the time consuming computational task of PWM signal generation by implementing the method of trigger pulse generation in a FPGA by using Hardware Description Language VHDL in Xilinx. The trigger circuit has been tested qualitatively by observing various waveforms on an oscilloscope. The operation of the proposed system has been found to be satisfactory.

• 천문학회지
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• 제56권2호
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• pp.225-229
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• 2023

We investigated an emerging magnetic loop dynamically formed on the Sun, which has the effective footpoint heating source that may play a key role in heating a solar atmosphere with free magnetic energy in it. It is suggested that the heating source could be related to local compression of a plasma in the emerging loop by means of Lorentz force, which converts the magnetic energy to the internal energy of the plasma that is used to reaccelerate a decelerated downflow along the loop, eventually generating the source when the kinetic energy of the downflow is thermalized. By analyzing very high-cadense data obtained from a magnetohydrodynamic simulation, we demonstrate how the local compression is activated to trigger the generation of the heating source. This reveals a characteristic of the emerging loop that experiences a dynamic loop-loop interaction, which causes the local compression and makes the plasma gain the internal energy converted from the magnetic energy in the atmosphere. What determines the characteristic that could distinguish an illuminated emerging loop from a nonilluminated one is discussed.

• 한국안전학회지
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• 제36권5호
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• pp.1-9
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• 2021

With the convergence of the information and communication technologies, a new age of technological civilization has arrived. This is the age of intelligent revolution, known as the 4th industrial revolution. The 4th industrial revolution is based on technological innovations, such as robots, big data analysis, artificial intelligence, and unmanned transportation facilities. This revolution would interconnect all the people, things, and economy, and hence will lead to the expansion of the industry. A high-density, high-capacity energy technology is required to maintain this interconnection. As a next-generation energy source, lithium-ion batteries are in the spotlight today. However, lithium-ion batteries can cause thermal runaway and fire because of electrical, thermal, and mechanical abuse. In this study, thermal runaway was induced in 72.5 Ah NCM pouch-type lithium-ion batteries because of thermal abuse. The surface of the pouch-type lithium-ion batteries was heated by the hot plate heating method, and the effect of the rate of increase in the surface temperature on the thermal runaway trigger time was analyzed using Minitab 19, a statistical analysis program. The correlation analysis results confirmed that there existed a strong negative relationship between each variable, while the regression analysis demonstrated that the thermal runaway trigger time of lithium-ion batteries can be predicted from the rate of increase in their surface temperature.

• 천문학회보
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• 제46권1호
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• pp.51.1-51.1
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• 2021

Spiral arms greatly affect gas flows and star formation in disk galaxies. We use local 3D simulations of vertically-stratified, self-gravitating, gaseous disks under a stellar spiral potential to study the effects of spiral arms on galactic star formation as well as formation of gaseous spurs/feathers. We adopt the TIGRESS framework to handle radiative heating and cooling, star formation, and ensuing supernova (SN) feedback. We find that more than 90% of star formation takes place inside spiral arms. The global star formation rate (SFR) in models with spiral arms is enhanced by less than a factor of 2 compared to the no-arm counterpart. This supports the picture that spiral arms do not trigger star formation but rather redistribute star-forming regions. Correlated SN feedback produces interarm feathers in both magnetized and unmagnetized models. These feathers live short, have parallel magnetic fields along their length, and are bounded by SN feedback in the lateral direction, in contrast to instability-induced feathers formed in our previous isothermal simulations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2441-2444
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• 2003

This paper describes fabrication of a micro cell counter integrated with an oxygen micropump and Sephadex G-25 beads counting experiment. The device utilized a phototransistor, microwindow, and light source of microscope for beads detection. Microheater and microchannel were used for pumping and guiding of beads to the microwindow. Counting capability of the device was tested with a peristaltic pump and the measured signals (${\sim}10\;mV$) with oscilloscope showed peak shape when beads passed the microwindow. Pumping of beads by the oxygen micropump was carried out by heating paraffin, which enveloped manganese dioxide (catalyst), to trigger the decomposition of hydrogen peroxide into water and oxygen. It lasted for 5 min with $7\;{\mu}l$ of wt. 30 % hydrogen peroxide. Beads counting by oxygen micropump showed peaks ($2{\sim}20\;mV$) with $30\;{\mu}l$ of beads sample and the number of peaks by magnitude was acquired.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3405-3409
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• 2013

The activation of heat shock factor 1 (HSF1) can be induced by the changes in environmental pH, but the mechanism of HSF1 activation by acidification is not completely understood. This paper reports that a low pH (pH~6.0) can trigger human HSF1 activation. Considering the involvement of the imidazole group of histidine residues under acid pH stress, an in vitro EMSA experiment, Trp-fluorescence spectroscopy, and protein structural analysis showed that the residue, His83, is the essential for pH-dependent human HSF1-activation. To determine the roles of His83 in the HSF1-mediated stress response affecting the cellular acid resistance, mouse embryo fibroblasts with normal wild-type or mutant mouse HSF1 expression were preconditioned by heating or pH stress. The results suggest that His83 is essential for HSF1 activation or the HSF1-mediated transcription of heat shock proteins, in protecting cells from acid pH stress.

• 한국해양공학회지
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• 제22권5호
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• pp.7-24
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• 2008

Masan-Jinhae Bay, in Korea, is known for its frequent algal bloom outbreaks. This study was conducted in order to examine the environmental characteristics of the area, with the aim of identifying indicators that could be used to speculate about future algal blooms. The water temperatures and salinities in Haengam Bay, one of the small inner bays within Jinhae, appeared to re relatively higher than those in Masan and Jinhae bays, across most seasons. Furthermore, stratification begins to develop in all three regions from spring to summer as a result of the local heating effects and an increase in the efficient from the surrounding land. As a result, anoxic conditions appear near the bottom layer of the bay, leading to the deterioration of water quality, which has been identified as one of the causes of bloom outbreaks. Compared to Haengam and Jinhae bays, concentrations of DIN and DIP were remarkably higher in Masan Bay. However, the mean ratio of DIN to DIP was 3.3$\sim$13.6 in all three regions throughout the year, suggesting that nitrogen can function as a growth-limiting factor for phytoplankton. The results of mathematical models showed that cumulative organic pollutants may be a trigger for direct algal bloom occurrences, since residual tidal currents appeared to be less than $3\;cm\;\cdot\;s^{-1}$. Furthermore, computed DO concentrations in the four small inner bays of Jinhae during the summer appeared to be $3\;cm\;\cdot\;l^{-1}$ indicating a hypoxic state. Likewise, computed Chl-a concentrations turned out to be more than $0.01\;mg\;\cdot\;l^{-1}$, indicating eutrophication across most seasons. Based on the overall results, Masan-Jinhae Bay appeared to possess a very high potential for algal bloom outbreaks at anytime during the year.

• The Plant Pathology Journal
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• 제29권3호
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• pp.350-355
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• 2013

Plants protect themselves from diverse potential pathogens by induction of the immune systems such as systemic acquired resistance (SAR). Most bacterial plant pathogens thrive in the intercellular space (apoplast) of plant tissues and cause symptoms. The apoplastic leaf exudate (LE) is believed to contain nutrients to provide food resource for phytopathogenic bacteria to survive and to bring harmful phytocompounds to protect plants against bacterial pathogens. In this study, we employed the pepper-Xanthomonas axonopodis system to assess whether apoplastic fluid from LE in pepper affects the fitness of X. axonopodis during the induction of SAR. The LE was extracted from pepper leaves 7 days after soil drench-application of a chemical trigger, benzothiadiazole (BTH). Elicitation of plant immunity was confirmed by significant up-regulation of four genes, CaPR1, CaPR4, CaPR9, and CaCHI2, by BTH treatment. Bacterial fitness was evaluated by measuring growth rate during cultivation with LE from BTH- or water-treated leaves. LE from BTH-treatment significantly inhibited bacterial growth when compared to that from the water-treated control. The antibacterial activity of LE from BTH-treated samples was not affected by heating at $100^{\circ}C$ for 30 min. Although the antibacterial molecules were not precisely identified, the data suggest that small (less than 5 kDa), heat-stable compound(s) that are present in BTH-induced LE directly attenuate bacterial growth during the elicitation of plant immunity.