• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.304-306
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• 2003

The KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting magnet system which consists of 16 TF coils and 14 PF coils. The magnet system adopt a superconducting CICC (Cable-In-Conduit Conductor) type. The KSTAR TF CICC uses Nb$_3$Sn superconducting cable with Incoloy 908 conduit. To prepare for TF CICC jacket defect, repair welding of TF CICC is studied. And to confirm join method of TF CICC joint part, the welding method and the joint part design are also discussed.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2003.10a
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• pp.307-310
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• 2003

The KSTAR (Korea Superconducting Tokamak Advanced Research) prototype TF (Toroidal Field) coil was tested in the superconducting coil test facility in KBSI (Korea basic Science Institute). The test was divided into several campaigns according to the objectives. The objectives of the first campaign were to cool the coil into operating temperature and to find any defect in the coil such as cold leaks. From the results of the first campaign, which was carried out during Jan. 2003, any defect in the TF prototype coil was not found. At the second campaign, the large-current charging experiment was one of the major issues, and was carried out during Aug. 2003 In this paper, the test preparation, and the test results of the second campaign were presented.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.405-409
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• 2008

Over 70% of the land is mountains in Korea, so that many roadways naturally includes tunnels. The air flow inside tunnel has complex characteristics, such that a new flow field is formed by following vehicles passing through the tunnel before previous flow field is stabilized. Due to these time delayed-transient characteristics, the ventilation facility requires the complex control algorithm that can handle adaptive and predictive controls. Also, it needs to be closely related to the disaster prevention system. The technology to integrate these system determines the success of TGMS. The pollutant levels exhausted from the vehicles passing through tunnel depend on vehicle years and passing velocity. They also depend on the slope and altitude of the tunnel. In order to solve this problem, an algorithm for estimating the compensating factors for calculating on design capacity of ventilation facilities was developed. Also, an integrated ventilation control algorithm with disaster prevention program to operate several tunnels was developed based on TGMS.

• Journal of the Korean Society of Safety
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• v.34 no.4
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• pp.32-40
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• 2019

During the manufacturing process of a printed circuit board(PCB), fumes and mists are generated as the ink dries on the PCB surface. The generated fumes and mists are deposited in the dryer wall and the exhaust duct. Deposited fumes and mists may present a fire hazard if the dryer temperature control system fails. In this study, the thermal stability of the fumes and mists deposited in the dryer and ducts has been analyzed by experimental methods such as thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC), auto ignition temperature (AIT), and multiple mode calorimetry(MMC). According to the experimental analyses, experimental samples are likely to generate gas at the temperature ($180{\sim}240^{\circ}C$) that deviates from the normal operating temperature ($150{\sim}156^{\circ}C$). It has been shown that the thermal stability is degraded when the temperature is deviated from the normal operating temperature. In the end, engineering and management safety measures of accidental prevention have been suggested.

• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.26-30
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• 2009

Korea Superconducting Tokamak Advanced Research(KSTAR) device is composed of 30 superconducting magnets, magnet structure, vacuum vessel, cryostat, current feeder system, and etc. KSTAR device is operated in the cryogenic temperature and high magnetic field. We install about 800 sensors - temperature sensors, stain gages, displacement gages, hall sensors - to monitor the thermal, mechanical, electrical status of KSTAR during operation. As a tremendous numbers of sensors should be installed for monitoring the KSTAR device, the method of effective installation was developed. The sensor test was successfully carried out to check its reliability and its reproduction in the cryogenic temperature. The sensor signal is processed by PXI-based DAQ system and communicated with central control system via machine network and is shown by Operator Interface(OPI) display in the main control room. In order to safely operate the device, any violations of mechanical & superconductive characteristic of the device components were informed to its operation system & operator. If the monitored values exceed the pre-set values, the protective action should be taken against the possible damage. In this paper, the system composition, operation criteria, operation result were presented.

• Biomolecules & Therapeutics
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• v.16 no.2
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• pp.87-94
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• 2008

In view of obtaining potential anticancer compounds, we studied the inhibitory activity and the cytotoxic effects of a candidate compound in cancer cells. The cytotoxic effects of cannabidiol (CBD) in vitro were evaluated in NIH3T3 fibroblasts, B16 melanoma cells, A549 lung cancer cells, MDA-MB-231 breast cancer cells, Lenca kidney cells and SNU-C4 colon cancer cells. The cells were cultured in various concentrations of CBD for 48 h and 25 ${\mu}$M of CBD for 6-36 h. The cells were observed to exhibit inhibitory effects of the cell viability in their growth, and then cytotoxicity was estimated. The inhibitory activity of CBD was increased in all cancer cells and showed especially strong increment in breast cancer cells. The cytotoxicity of CBD increased in a dose- and time-dependent manner with growth inhibition in all cancer cell lines. Also, to assess the membrane toxicity induced by CBD, we investigated lactate dehydrogenase (LDH) release. After treatment with various concentrations of CBD, LDH release rate of cancer cells was accelerated. On the other hand, in the induction of cell death, caspase-3, -8 and -9 activations were detected in cancer cells after treatment with various concentrations of CBD, and CBD effectively induced activity of caspase-3, -8 and -9 in A549 lung cancer cells, MDAMB-231 breast cancer cells and Renca kidney cells. Therefore these results suggest that CBD has a possibility of anticancer agents and anticancer effects against cancer cells by modulation of apoptotic pathway in the range of 5-80 ${\mu}$M concentration.

• Journal of Society of Preventive Korean Medicine
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• v.11 no.1
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• pp.23-34
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• 2007

Health promotion program utilizing traditional korean medicine(TKM) is very unique modality uncommonly conducted throughout the world. Korea's TKM public health services went through initial stage from 2001 and spread throughout the country by 2003. 35 public health centers in the nation is appointed as 'TKM health promotion HUB' and in operation from 2007. But the program is still in the early state and evaluation of usage, satisfaction, and community service is still in demand. This study aims to verify current situations of TKM public health service by examining public awareness, usage, and satisfaction and suggest improvements based on findings. 2.5% of local residents were sampled and 1739 were chosen as subjects. Knowledge, attitude, satisfaction and others for TKM public health service were examined. TKM treatment service was most widely utilized(13.2%), followed by CVA prevention program(5.2%). For satisfaction level, CVA prevention program showed highest satisfaction(73.3%), closely followed by (Qi-gong program 63%). In general, awareness and utilization of TKM public health service were low but compensated by high satisfaction level. More active promotion and development of community specific programs should become available in the future.

• Fire Science and Engineering
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• v.19 no.2 s.58
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• pp.75-80
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• 2005

This dissertation is about the development of PTC(Positive Temperature Coefficient) thermistor by composition method. A multilayer-type PTC samples were fabricated under optimal conditions after setting the experimental composition equation as $(0.90Ba+0.05Sr+0.05Ca)TiO_3+0.01TiO_3+0.01SiO_2+0.0008MnO_2+0.0018Nb_2O_5$ and their testing results were analyzed. The fabrication method of SMD(Surface Mounted Device) multilayer -type sample based on the composition ratio has the advantages in lowering its resistivity at room temperature, considerably, and increasing maximum current level, as needed. Although there is a disadvantage of peak resistivity drop by the multilayer, causing the increasement of thermal capacity. and thereby, increasing the switching delay time, a high applying voltage can increase the peak resistivity and shorten the switching delay time. The voltage-current characteristic showed that the more multilayers increased the initial maximum current and the transition voltage that increased the resistivity abruptly according to the curie point. The element it could be applied with the sensor for the fire detector.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.9
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• pp.32-37
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• 2003

The trend of miniaturization has been applied to the research on micro rockets resulting in prototype rockets fabricated by MEMS processes. In this paper, the development of three-dimensional micro rockets using micro milling as well as the results of combustion and flight tests are discussed. The body of rocket was made of 6061 aluminum cylinder. The three-dimensional micro nozzles were fabricated on brass by micro endmill with 127${\mu}m$ diameter. Two different micro nozzles were fabricated, one with 1.0mm of throat diameter and the other with 0.5mm. The total mass of rocket was 7.32g and that of propellant was 0.65g. The thrust-to-weight ratio was between 1.58 and 1.74, and the flight test with 45 degree launch angle form the ground resulted in 46m-53m of horizontal flight distance

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.141-149
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• 2018

In a PCB factory, there is a corrosive chemical substance supply system that can causes major leakage accidents. These accidents can give rise to shut down the factory and do residents damage that cause enormous loss of properties. To mitigate these risks, it is necessary to provide a chemical disaster prevention system. Moreover, after considering the situation and environment of the production site, it is of great importance to build an optimal chemical accident prevention system by reflecting risk reduction measures from the point of process design and by assessing quantitative risk based on reliability data. However, because there was no established database of the reliability about facilities and equipment that can be used in the domestic, the business site and consulting organization had being used the reliability data such as USA CCPS(Center for Chemical Process Safety). In these days, Korean institutes are studying on reliability data utilization method of quantitative risk assessment for preventing chemical accidents and domestic utilization algorithms and storage bed of reliability data. This study presents samples of reliability database about the chemical substance supply system that constructed from the history data such as failure, maintenance for 10 years at a PCB factory. Also, this work proposes the safety design criteria for supply facilities of corrosive chemical substance by assessing quantitative risk on the basis of the reliability data.