• Fire Science and Engineering
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• v.27 no.6
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• pp.89-96
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• 2013

The purpose of this study is to check the fire origin and cause of the fire by observing the shape of the flame propagation in air-conditioner indoor unit through the fire tests. We supposed that the flame is spread from the surroundings to the top of the air-conditioner and ignited on top of the air-conditioner with n-heptane. And then repeated this experiment twice under the same conditions. After the ignition, refrigerant filled in air-conditioner and lubricating oil exploded with large explosion and flame having high temperature and pressure belched out rapidly due to bursting refrigerant pipe linked air-conditioner between 734 seconds and 559 seconds. After result of checking the combustion residue we found that almost all of that was lost except a part of the evaporator, motor and metal. The position of short-circuit traces of wiring for the air-conditioner ignited itself is similar to that of fire damage by external flame. Therefore, we verified that it is not certain to determine the ignition cause and point by only the shape of the combustion residues.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1051-1057
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• 2011

By the recently developed GMP(Glass Molding Press) process, aspheric glass lenses are widely used in many optical applications such as digital cameras, optical data storages and electrical devices etc. The GMP process can economically produce complex shaped glass lenses with high precision and good repeatability. This study deals the optimization of molding conditions for aspheric glass lenses in progressive GMP process through Design Of Experiment(Taguchi method). Tree main factors for molding conditions were selected based on pressure, temperature and cooling time at 1st cooling stage. From the analysis of experiments which were preformed with 3-cavity glass mold, it was revealed that the cooling time was the most sensitive parameter for form accuracy(PV) in progressive GMP process.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.623-634
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• 2006

In this study, characteristics of fog at Mokpo as the west coastal area of Jeonnam were investigated, using statistical analysis of observed fog and meteorological data. Higher frequency of the fog occurrence at Mokpo was showed in spring(32%) and summer(34%) due to the seasonal high atmospheric pressure. Regional characteristics as radiation cooling, advection of fog and water vapor from surrounding sea and Yeongsan lake, and frontal fog had major effect on the coastal fog at Mokpo on the meteorological conditions of north-west/south wind and calm($0{\sim}2m/s$). Also, as the results of analyzing data of before and after the construction of Yeongsan dam, the frequency of annual mean fog days increased 41 %, specially increased 178% in autumn. The increase of fog days mainly resulted from evaporation during colder seasons and from temperature inversion during warmer seasons over the water surface of Yeongsan lake. The construction of Yeongsan dam had a little effect on the meteorological conditions concerning fog occurrence, because Yeongsan dam which only supplies the water for use do not always carry out outlet of the cold water. In addition, the sea fog at Heuksando located in offshore had not effect on the occurrence of fog at Mokpo.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.775-788
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• 2007

This study was aimed to understand the structures of preservice secondary school teachers' alternative conceptions on radioactive isotopes in the interior of earth. The structure of their conceptions were analyzed by the suggestions of Niaz (1988) based on the Lakatosian frameworks. The survey was carried out on a group of seventeen students who were major in science education. The research method was open-ended written questionnaire. The results of this study show that students had apparent alternative conceptions. The high temperature and pressure' explanation for radioactive decay in earth's interior had most import effects on their alternative conceptions. It was also intended to survey their conceptional change by our teaching strategies of the philosophy of science in order to construct science concepts.

• Atmosphere
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• v.29 no.4
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• pp.451-461
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• 2019

Medium-range forecast is highly dependent on ensemble forecast data. However, operational weather forecasters have not enough time to digest all of detailed features revealed in ensemble forecast data. To utilize the ensemble data effectively in medium-range forecasting, representative weather patterns in East Asia in this study are defined. The k-means clustering analysis is applied for the objectivity of weather patterns. Input data used daily Mean Sea Level Pressure (MSLP) anomaly of the ECMWF ReAnalysis-Interim (ERA-Interim) during 1981~2010 (30 years) provided by the European Centre for Medium-Range Weather Forecasts (ECMWF). Using the Explained Variance (EV), the optimal study area is defined by 20~60°N, 100~150°E. The number of clusters defined by Explained Cluster Variance (ECV) is thirty (k = 30). 30 representative weather patterns with their frequencies are summarized. Weather pattern #1 occurred all seasons, but it was about 56% in summer (June~September). The relatively rare occurrence of weather pattern (#30) occurred mainly in winter. Additionally, we investigate the relationship between weather patterns and extreme weather events such as heat wave, cold wave, and heavy rainfall as well as snowfall. The weather patterns associated with heavy rainfall exceeding 110 mm day^-1 were #1, #4, and #9 with days (%) of more than 10%. Heavy snowfall events exceeding 24 cm day^-1 mainly occurred in weather pattern #28 (4%) and #29 (6%). High and low temperature events (> 34℃ and < -14℃) were associated with weather pattern #1~4 (14~18%) and #28~29 (27~29%), respectively. These results suggest that the classification of various weather patterns will be used as a reference for grouping all ensemble forecast data, which will be useful for the scenario-based medium-range ensemble forecast in the future.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.45-55
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• 2017

Release and fire/explosion tests of flammable gas are extremely dangerous. Furthermore, it is difficult to select the site where the experiment can be performed. In these reasons, gas flow analysis(CFD) has been used as much as possible. However, with the opening of the Energy Safety Empirical Research Center in Yeongwol-gun, Gangwon-do in October 2016, it was possible to conduct releases and detection tests of small scale combustible gas as well as large scale / high pressure / ultra low temperature experiments. In this study, LPG leaked after the calibration and placement of the sensor, the sensor detected LPG and the data were visualized as a contour map. And the differences between the actual release(28s, max 3.7[m]) and the analysis were analyzed compared to the FLACS analyzed under the same conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1857-1863
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• 2010

We present the fabrication and characterization of transparent carbon nanotube film (CNF) piezoresistors. CNFs were fabricated by vacuum filtration methods with 65?92% transmittance and patterned on Au-deposited silicon wafer by photolithography and dry etching. The patterned CNFs were transferred onto poly-dimethysiloxane (PDMS) using the weak adhesion property between the silicon wafer and the Au layer. The transferred CNFs were confirmed to be piezoresistors using the equation of concentrated-force-derived resistance change. The gauge factor of the CNFs was measured to range from 10 to 20 as the resistance of the CNFs increased with applied pressure. In polymer microelectromechanical systems, CNF piezoresistors are the promising materials because of their high sensitivity and low-temperature process.

• Biomolecules & Therapeutics
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• v.12 no.2
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• pp.114-121
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• 2004

This study was undertaken to evaluate the general pharmacological properties of CJ-11828, an amlodipine adipate, in experimental animals and in vitro system. CJ-11828 had no effects on general behavior, motor coordination, writhing syndromes, pentetrazol-induced chemoshock and electric shock in mice at dose levels of 3,10, anti 30 mg/kg, po. But there were decrease of body temperature, prolongation of sleeping time, and inhibition of intestinal activity in mice treated with CJ-11828 at doses of 10 and 30 mg/kg, po. CJ-11828 decreased the blood pressure in coscuous fog at the dose level of 2mg/kg, po, but it was expected as a result of pharmacological activity of CJ-11828. Any effect on respiratory system was not observed in conscious rat at doses of 3,10, and 30 mg/kg, po. The slight decrease in spontaneous motor activity was observed in mice treated with CJ-11828 at high dose, 30 mg/kg. In vitro experiments, CJ-11828 had no effect on agonists-induced contraction of isolated guinea pig ileum at 0.1, 1, and 10 ${\mu}$M. Based on these results, it was concluded that CJ-11828 had no pharmacological effect ill these studies even up to the 36-fold anticipated clinical dose, 3 mg/kg.

• Journal of fish pathology
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• v.33 no.1
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• pp.97-101
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• 2020

Although aquaculture production rates grown over the years, aquatic animal diseases occur every year which causes substantial economic losses. When an aquatic animal is infected with an aquatic animal pathogen it is either incinerated or buried according to the aquatic life disease control act. Although these methods prevent the spread of disease, it is not environment friendly. Here, we developed an aquatic animal rendering equipment for disposal of fish waste which is environment-friendly and efficient. Also, fertilizer components of fish waste were evaluated value for recycling. The mobile rendering equipment was designed for field operation and/or high temperature and pressure system, oil and water separator, and shredding drying apparatus. During the experiment (July-2016 to November-2016), a total of 53,824 kg fish waste was collected, and 29,216 kg compost of rendering by-product was made. Also, compost made from viral (Viral hemorrhagic septicemia virus) infected fish did not reflect any detectable pathogen. The concentration of nitrogen, phosphorus, and organic matter in the fish waste compost were 2.17%, 26.98%, and 92.44%, respectively. The results suggest that fish waste used in this study was decomposed efficiently as per the official standard for fertilizer product. This equipment can be useful for efficient inactivation of the aquatic animal pathogenic agents and recycling of the fish waste in an environment-friendly manner.

• Annals of Clinical Neurophysiology
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• v.19 no.2
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• pp.118-124
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• 2017

Electroencephalography (EEG) is frequently used to assist the diagnosis of brain death. However, to date there have been no guidelines in terms of EEG criteria for determining brain death in Korea, despite EEG being mandatory. The purpose of this review is to provide an update on the evidence and controversies with regarding to the utilization of EEG for determining brain death and to serve as a cornerstone for the development of future guidelines. To determine brain death, electrocerebral inactivity (ECI) should be demonstrated on EEG at a sensitivity of $2{\mu}V/mm$ using double-distance electrodes spaced 10 centimeters or more apart from each other for at least 30 minutes, with intense somatosensory or audiovisual stimuli. ECI should be also verified by checking the integrity of the system. Additional monitoring is needed if extracerebral potentials cannot be eliminated. Interpreting EEG at high sensitivities, which is required for the diagnosis of brain death, can pose a diagnostic challenge. Furthermore, EEG is affected by physiologic variables and drugs. However, no consensus exists as to the minimal requirements for blood pressure, oxygen saturation, and body temperature during the EEG recording itself, the minimal time for observation after the brain injury or rewarming from hypothermia, and how to determine brain death when the findings of ECI is equivocal. Therefore, there is a strong need to establish detailed guidelines for performing EEG to determine brain death.