• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.424-425
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• 2018

In the introduction, this paper introduces LS Industrial Systems' medium-voltage drive installed at Hyundai Green Power, an 800MW gas power plant. In the body, it explains the synchronous transfer technology and new speed search technology applied to Forced Draft(FD) Fan and Boiler Feed-water(BF) Pump, which are power generation facilities. Lastly, it shows the annual energy saving amount and operation status which are applied to each facility and proves that it is a successful application case.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.13 no.2
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• pp.1-9
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• 1984

This paper presents design conditions due to the NTU of counter and cross flow type cooling tower. In the calculation of optimum design conditions for above two types which are widely used in our country, standard water-air ratio, ambient wet bulb temperature and bulk water temperature were adopted by domestic wheather conditions. The important result of this study is obtained as follows : Under the constant value of Ka and L, the number of transfer unit of cross flow type cooling tower Is about 1.1 times as large as that of counter, so the volume of cross flow type is about $10\%$ greater than that of counter.

• Journal of the Korean Society of Industry Convergence
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• v.19 no.4
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• pp.216-222
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• 2016

Thus, this study aimed to develop a gear-type vane damper in order to replace the link-type vane damper. To achieve this goal, the torque generated in a gear-type vane damper was analyzed, and a structural analysis was conducted. In addition, the fluid flow was analyzed according to the changes in the vane's angle, and experimental tests such as a dry-heat test and cold test were conducted considering the operating conditions of the vessels. Moreover, an appropriate actuator was selected for the developed gear-type vane damper, and studies on the reduction in the backlash due to the facing-pressure adjustment length and flow rate and leakage test due to the vane's angle were conducted.

• Bulletin of the Society of Naval Architects of Korea
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• v.14 no.3
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• pp.13-22
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• 1977

The hydrodynamic forces acting on a forced oscillating 2-dimensional cylinder on a free surface of a fluid of a finite depth are calculated by distributing singularities on the immersed body surface. And the Haskind-Newman relation in a fluid of a finite depth is derived. The wave exciting force of the cylinder to an oscillation is also calculated by using the above relation. The method is applied to a circular cylinder swaying in a water of finite depth, and then, to a rectangular cylinder heaving, swaying, and rolling. The results of above cases give a good agreement with those by earlier investigators such as Bai, Keil, and Yeung. Also, this method is applied to a Lewis form cylinder with a half beam-to-draft ratio of 1.0 and a sectional area coefficient of 0.941, and to a bulbous section cylinder which is hard to represent by a mapping function. The results reveal that the hydrodynamic forces in heave increase as the depth of a water decrease, but in sway or roll, the tendency of the hydrodynamic forces is difficult to say in a few words. The exciting force to heave for a bulbous section cylinder becomes zero at two frequencies. The added mass moment of inertia for roll is seemed to mainly depend on the sectional shape than the water depth.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.3
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• pp.130-136
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• 2014

The present study is performed to set up the framework of cooling tower performance predictions. The performance of mechanical forced draft cooling tower is directly related to the state of a nuclear power plant system, such as the condenser and evaporator. The main parameters related to the state of systems are as follows : wet bulb temperature, dry bulb temperature and absolute humidity. The performance evaluation of cooling tower must be considered at the power plant design. In this study, the toolkit developed by the American Cooling Tower Industry association (CTI) has been used for the framework construction. In order to validate the framework, it is being applied to the cooling tower constructed for the U.S. Nuclear Power Plant. The test results have shown good agreements with the cold water temperature on the cooling tower performance curves provided by manufacturers.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.375-380
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• 2008

This study have processed the developing of vane damper with accurate control by using gear which is a flow-control equipment of marine boiler's FD fan on this research. For the developing of vane damper, we have corrected some problem from welding & assembly process by changing the design, and for the case of an emergency case, we have applied the easy disassembly & assembly on that vane damper. Compared to Rink type vane damper in current, we have focused on high efficiency with low price of that new developing damper. For selection of actuator, we have tried to find the propriety with our developing focus. Also, we have developed a jig of assembly processing for high productivity with quality, it caused the best assembly performance with heat-treated & processed parts.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.8
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• pp.24-30
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• 2019

This study investigated the heat dissipation characteristics of a heat-sensitive LED. The results of the empirical test showed that the best temperature intensification was found at 90 with 15-fins, and the heatsink installed perpendicular to the direction of the flow of air was directly connected to the air in the largest heat shield area, leading to the best cooling, and the number of fin also resulted increase in the heat discharge area, resulting in the largest cooling action with 15 fins. It was found that the rate of air flow changed in the range of 1.5m/s to 2.5m/s, but only by a deviation of about $2^{\circ}C$ to $3^{\circ}C$ from the current state of 15 fins at 2.5m/s, and the rate of air flow increased, but the performance of the heat release was not significantly increased. As a result wind speed with minimum air flow conditions of 1.5m/s can greatly contribute to the heat dissipation performance.

• Asia pacific journal of information systems
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• v.33 no.2
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• pp.389-417
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• 2023

Social distancing required the use of doorstep delivery for nearly all purchases during the COVID-19 pandemic. Foreign users in Korea are forced to participate in superfluous tasks, leading to an increase in their anxiety and fatigue while online shopping. This study examines how digital shadow work stemming from the language barrier can affect the emotions and behaviors of foreign shoppers that use Korean shopping sites. By interviewing 37 foreign users in Korea, this draft examined their experiences, behaviors, and emotional output, classifying them into 14 codes and seven categories. Using grounded theory, we found that online shoppers' emotions, feelings, experiences, and decision making may be changed in the stages of the pre-use, use, and post-use activities. User responses regarding shadow work and related obstacles can be seen with the continue, discontinue, and optional (occasional use) of Korean online shopping sites. Pleasure and satisfaction come from high efficiency and privileges, whereas anger and disappointment come from poor self-confidence and pessimism. Furthermore, buyer behavior and product orientation are identified as intervening conditions, while the online vs. offline shopping experiences are identified as contextual conditions. In conclusion, language barriers and other factors make online shopping difficult for foreign shoppers, which negatively affects their psychological mechanisms and buying behaviors. The implications from the study findings and future research are also discussed.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.24-27
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• 2003

In this paper it was investigated 15 heaters of CDU plant heater, NCC plant heater, CO plant heater, Aromatic plant heater and so on while running in our country. It was also analysed the standard of operation procedure, the action in alarm, the interlock system, the operating situation of the interlock by-pass and major accident about the heater and so on. This paper presents the installation of the on-line monitoring, the additional installation of the local pressure gauge and temperature gauge, the check in starting operation,'the management of the interlock by-pass, the change of manufacturer causing the disorder of instrument sensor, the management method of DCS alarm for methods of the interlock prevention and facilities improvement. It was few information about the heater interlock in the inside and outside of the country We mainly have studied with reflecting the opinion of the operator and manager on site, the sheet of process trouble and operation procedure and so on. we think that the accident relating to the interlock will significantly reduce if the companies apply the conclusion of this study(i.e. methods of the interlock prevention and facilities improvement).

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1355-1364
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• 1998

This study was planned to investigate the effect of 40 plant ethanolic extracts on antioxidant activities in vitro. The total phenolics, $\beta$-carotene, $\alpha$-tocopherol and selenium contents were also determined . Antioxidant activities fo the ethanolic extracts(0.02%, w/w) in the soybean oil were measured both by determining the peroxide value (POV) during 35 days of storage at 4$0^{\circ}C$ in a forced draft air-incubator and by determining changes in conductivity at 11$0^{\circ}C$(Rancimat method.). Soybean oil without any additives was used as a control and that treated with 0.02% BHT was used as a positive control. Based on the POV determination, green tea extract was found to be the most effective in stabilizing soybean oil, then followed by long tea, which both of them showed higher antioxidant activities compared to the BHT treatment. The antioxidant activities of them showed higher antioxidant activities compared to the BHT treatment. the antioxidant activities of coffee, cinnamomi cortex, acanthopanacis cortex, black tea, orange peel , instant coffee, peony and crni fructus extracts were stronger compared to the control .By the Rancimat method, green tea leaf and oolong tea leaf, foxglove, acanthopanacis cortex and peony extracts. Compared to other extracts, green tea leaf, black tea leaf, foxglove, acanthopanacis cortex and peony extracts had stronger antioxidative effects in both the POV and Rancimat methods used in this study. ethanolic extracts which showed the stronger antioxidative effect also has the higher contents of total phenolics, $\beta$-carotene, and/or $\alpha$-tocopherol. The antioxidative effect of ethanolic extracts was found to be due to the combined effect of various antioxidants.