• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.541-550
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• 2019

An emergency generator is key equipment for fire-fighting to supply power to fire-fighting facilities, which protect property and people in cases of fire accidents. A rated load test for emergency generators must be carried out by connecting an emergency load to the generator in accordance with related regulations. However, a no-load test has been performed for emergency generators in general since serious problems can occur when the main power is cut off, including the damage of customer devices and shut down of critical loads. Therefore, this paper proposes a load test method for an emergency generator using energy storage system (ESS) without the interruption of main power. The emergency power system was also modeled based on PSCAD/EMTDC software, and a 200-kW scale ESS load test device was implemented. The simulation and test results show that the load test method is useful and practical for an emergency power supply system.

• Applied Chemistry for Engineering
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• v.30 no.3
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• pp.365-370
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• 2019

In this study, effects of the ultrasonic irradiation during the reaction process were investigated for the enantioselective kinetic resolution (EKR) reaction of racemic epoxides in the presence of chiral cobalt salen catalysts, as compared to that of using the conventional mechanical stirring. In order to compare catalytic activities, the chiral cobalt salen complexes having $AlCl_3-$, $BF_3-$ and nitrobenzenesulfonic acid (NBSA) were synthesized and used as catalysts, and then three kinds of the racemic epoxides such as ephichlorohydrine (ECH), epoxy phenoxypropane (EPP) and propylene oxide (PO) were used as reactants. In addition, EKR reactions have been performed using the water and methanol as nucleophiles, respectively. The unique contribution of ultrasonic irradiation as a powerful mixing medium was evaluated in this study to improve the kinetics in comparison to the conventional mechanical agitation during EKR reactions. The reaction time to obtain the highest 99 ee% became shorten more than that of above 60%, when the ultrasonic irradiation was used. This result may be interpreted by the cavitation effect of ultrasound in the solution, generating a powerful shear force for the very violent mixing.

• Journal of the Korean Geosynthetics Society
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• v.18 no.3
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• pp.33-44
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• 2019

Clinker layer is a stratum structure distributed in volcanic area such as Jeju Island. The clinker layers were formed in between the repetitive action of eruption and solidification of lava flows. Since the clinker layer contains a large amount of voids accompanied by the lava gas ejection process, there is a possibility of inducing overall stability of the ground due to the low stiffness and strength of the clinker layer. Therefore, in this study, site investigation was carried out at both ends of the 00 bridge where the clinker layers exist. And, based on the ground survey results, the behavior of shallow foundations was analyzed numerically. In addition, the improved shallow foundation behavior in grouting substitution using the chemical injection method of the clinker layer was compared with the shallow foundation behavior in the ground, and the grouting substitution efficiency of each layer was analyzed. As a result, the bearing capacity, the replacement efficiency and elastic settlement were different according to the presence or absence of the sediment layer. This is because the sediment layer has a lower stiffness and density than the clinker layer.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.4
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• pp.43-52
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• 2020

As the membrane gas separation technology grows, various models were developed by numerous researchers to describe the separation process. In this work, the counter-current model was compared thoroughly with experimental data. Experimentally, hollow fiber membrane using CA module was prepared for the separation of biogas. The pure gas permeation properties of membrane module for methane, nitrogen, oxygen, and carbon dioxide were measured. The permeance of CO2 and CH4 were 25.82 GPU and 0.65 GPU, respectively. The high CO2/CH4 selectivity of 39.7 was obtained. the separation test for three different simulated mixed gases were carried out after pure gas test, and the gas concentration of the permeate at various stage-cut were measured from CA membrane module. Results showed that the experimental data agreed with the numerical simulation. A mathematical model has implemented in this study for the separation of biogas using a membrane module. The finite difference method (FDM) is applied to calculate the membrane biogas separation behaviors. Futhermore, the counter-current model can be considered as a convenient model for biogas separation process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.197-207
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• 2021

According to the analysis of Kolb's learning style, Korean university student pilots interpret and attach meaning to themselves. Moreover, as the school year progresses, they enter the flight-training course with a 100 % diverger style, which is a variety of thoughts and imaginative learning styles. As the school year progresses, some changes occur with accommodator (11.1%) and assimilator (15.9%) styles. On the other hand, most students remain as the diverger style (71.4%). In the case of U.S. student pilots, most in first-year are assimilator (35.5%) and converger (24.3%) styles, and the proportion of the converger style increases as the senior year is approached. In the first grade, most Chinese student pilots are assimilators (41.5%) and convergers (28.4%), but in the higher grade, the proportion of assimilators and convergers decrease, and the proportion of diverger styles increases dramatically. In the fourth grade, the accommodator was similar to the first grade, but the converger style continued to decrease (41.5% in the first grade and 27.0% in the fourth grade).

• Journal of Legislation Research
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• no.54
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• pp.217-259
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• 2018

The Trust Act, which was first enacted back in 1961, was fully revised on 25. July 2011 and enacted on 26. July 2012. The Act is a fundamental norm governing trust relation, so the revision was expected to play an important role to promote trust institutions. However many problems were also revealed after the enactment. The Act has already inherent limitations because the previous discussions were not enough and the amendment process was not meticulously reviewed. Now it is needed to consider the comprehensive amendment of the Act reflecting detailed legal doctrines developed hitherto by the courts and the legal academia. This paper aims to call for the revision of the Act and to propose the ways and the grounds for revision. The purpose of the revision is to rectify obvious errors on several provisions, to minimize legal uncertainty by presenting detailed rules on many issues, to enhance the coherence and consistency between the rules along with supplementing the relevant laws, and to strike a proper balance between the parties.

• 한국노년학
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• v.28 no.4
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• pp.1113-1128
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• 2008

Purpose: The aim of the present study was to investigate toilet terms and pictograms recognized by elders living in Seoul and Incheon. Method: Data were collected from 308 elders by individual interviews using questionnaires. Result: As for the name of places for elimination, those elders responded Hwajangsil 88.3%, followed by Byeonso 49.3% and Dwitgan 44.4%. Most elders preferred Hwajangsil as the term indicating the place for elimination. The mean age of the group preferred Bunso was significantly higher than that of the group preferred Hwajangsil, whereas educational level was higher in the latter group. Of the 256 respondents, 55% preferred the pictogram of international toilet sign, while 34.8% preferred the pictogram of toilet stool. Those with no formal education tended to prefer the pictogram of toilet stool. Conclusion: The term Hwajangsil is suggested for indicating toilet for elders in general. Other terms familiar with residents need to be investigated in the facilities for elders and those terms should be used in combination with Hwajangsil. English toilet signs alone are not recommended for elders. Simple pictograms of toilet stool is suggested for elders with low educational level. Toilet signs for elders need to include both terms and pictograms.

• (The)Study of the Eastern Classic
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• no.72
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• pp.97-126
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• 2018

has many sexual elements among our literature. So is considered obscene. But if you take a closer look at , you can see that he is dealing with the real problem. Especially, the conflict between Gangsoe and Jangseung shows the contradiction of reality. However, it can not be questioned because it is hidden behind sexual elements. 's strategy of revealing is similar in Media Narrative. has been made into a film since the 1980s. However, these films stayed at the level of B-erotic movies. The real meaning of is gone, and the sexual image is more emphasized. Incidentally, this aspect is related to reality at the time. At that time, the military was in control of politics. So I wanted the people not to be interested in politics. For this reason, many erotic movies were created. Eventually, the strategy of revealing was even more maximized in Media Narrative. But recently there was a new attempt like . This was a new attempt to go beyond the standardized approach. Future interpretations of are expected more.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.768-776
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• 2021

Current protection-coordination methods use the reverse time characteristics of the T-C curve, which is not effective for a LVDC distribution system because the protective operation time of converters and DC circuit breakers is much faster than AC protection devices. Therefore, an algorithm is proposed for fault-section isolation using the fault current slope to minimize the blackout region and coordinate between converters and protection devices in a rapid and accurate manner. The method deals with the slope characteristics of a fault current, which may depend on the fault location in an LVDC distribution system. Thus, an LVDC distribution system can be operated in a stable manner by isolating the fault section selectively before the shutdown of the main converter using slope characteristics, which change in proportion to the line impedance and fault location. A 1.5-kV LVDC distribution system was modeled to verify the effectiveness of the proposed algorithm using PSCAD/EMTDC. The system is composed of a distribution substation, LVDC converter, and distribution lines. The simulation results confirm that the proposed algorithm is a useful tool for minimizing the fault section in an LVDC distribution system.

• Journal of the Korean Institute of Gas
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• v.25 no.6
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• pp.53-65
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• 2021

While the hydrogen refueling station is rapidly expanded and installed, the safety inspection of the hydrogen pressure vessel in the station should be very important. Of these, according to ASME, hydrogen embrittlement tests must be performed for hydrogen vessel that store hydrogen above a certain pressure. The main test method for hydrogen embrittlement inspection is to carry out fracture tests and fatigue fracture tests in a high pressure hydrogen atmosphere, which allows the durability limit of the pressure vessel to be measured and the endurable limit to be determined in the hydrogen atmosphere. In detail, the critical crack depth can be calculated by the stress intensity factor(K), and the service life can be determined by da/dN (fatigue growth rate). API579-1/ ASME FFS-1 part 9 exemplifies the calculation method according to the mode of crack-like flaws, but for various shapes such as plates and cylinders, there are about 55 modes according to the shape and location of the crack. Due to the fairly complex formula, it is not easily accessible. In this study, we will show you how to calculate fracture mechanics numerically via Excel and VBA. In addition, this was applied to analyze the effects of the thickness and inner diameter of the pressure vessel on the service life.