• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.1
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• pp.40-50
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• 2016

In order to recover the power system during the wide power outage or power failure in the power plant, black start system should be properly operated without any problem. Especially power for black start in the geographically isolated areas of electric island is supplied from small emergency start-up generator, and loads are aux systems of gas turbines such as SFC(Static frequency converter). This paper introduces the international practices to overcome the voltage drop problem with harmonics of the system having the DC output such as SFC during black start in weak feed system and analyzes the relationship between house load inputs and harmonics. By varying the house load and input of power supply, this paper identified boundaries between weak feed and strong feed power. In order to verify the theory of stable condition in weak feed power system with DC output, house load is simulated using ETAP. Additionally MATLAB was used for harmonic analysis between the load inertia moment and non load inertia moment.

• The International Journal of Costume Culture
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• v.9 no.1
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• pp.77-81
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• 2006

From the viewpoint of color perspective, black has more obvious effects to impart images than dress itself This study aims to examine black dress through the fashion history to highlight the aesthetic value of black and to make better use of black in designing. Black in fashion, particularly in the guise of the little black dress, became an indispensable feature of cosmpolitan style after World War I. Designers harnessed the power of black, drawn irresistibly to its innate qualities of drama and strength of line. For the past five hundred years, aside from the use of black for mourning as well as for religious, academic, legal and ceremonial dress, black with a greater or lesser dominance has been a fashion constant. Since then black has been an important color in fashion. How to use black in formative designs should be studied continuously.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2119-2126
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• 2016

In this paper, we developed a smart black box that can monitor and record the information of the sensor from subsystem in the smart grid system. The plant is the complex power system which is integrated by solar power system, grid-connected power systems, and BESS(battery energy storage system). The black box with the web-server application can connect and synchronize to an external monitoring system and a smart phone. We hope that this system is to contribute to improve operational efficiency, reliability, and stability for the smart grid power system.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.229-230
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• 2012

Platinum (Pt) has been commonly used as a counter electrode material in dye-sensitized solar cells, because it has high catalytic activity and electric conductivity as well as chemical inertness with iodide electrolyte. However, Pt is too expensive to be commercialized. Therefore, in the present study, carbon black counter electrode with Pt and carbon nano tube (CNT) was investigated. The power conversion efficiency with Pt added carbon black electrode was lower than hat of pure Pt electrode which was 6.47 %. By adding 3 wt% Pt to the carbon black counter electrode, the power conversion efficiency was maximized at 5.88 %. On them, additional adding of 1 wt % CNT, the power conversion efficiency (${\eta}$)wasincreasedupto6.21%. The reason of power conversion efficiency improvement with a proper amount of Pt and CNT was examined by comparing the impedance properties measured using EIS.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.160-167
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• 2018

In this paper, a black box, which is provided the reliability and user safety of home battery energy storage system connected with solar energy generation, is developed. In the developed scheme, a status and diagnosis data of battery management system, power conditioning system, solar energy generation and grid is measured. This status and diagnosis data is stored and displayed in the developed black box. In addition, this status and diagnosis data is stored and displayed in a monitoring system and a smart phone of user. A performance evaluation of the developed black box is carried out using emulator of home battery energy storage system connected with solar energy generation. Consequently, the developed black box is proved its superiority of the reliability and user safety.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.210-226
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• 2021

The purpose of this study is to explore the American black film director Ryan Coogler and his cinema world. Coogler as a youth director directs three movies as (2013), (2015), (2018) from independence film to Hollywood film, and represents black people' life and racial discrimination base on his cultural identity. For this study, explore traits of esthetics, subject and context meaning by analyzing representative three movies. Lastly examines significance of his movies in Hollywood black film history. He represents blackness and self-reflection as a black youth director, and successfully succeed to the tradition of 'Black Film' in American film history. He also turn white patriarchal ideology upside down in Hollywood. He inherits the tradition of 'Black Film' in American film history, and simultaneously tries to re-write black film tradition. Youth director Coogler is a symbol of 'New Hollywood Black Film Power' at the 21th.

• The Korean Journal of Food And Nutrition
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• v.30 no.1
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• pp.175-180
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• 2017

To enhance the physiological activities and reduce the off-flavor of garlic in the Kimchi, we manufactured the Kimchi seasoning replaced with 25~75% black garlic instead of raw garlic and measured the contents of antioxidants and antioxidant activities. The polyphenol compound content was $270.91{\mu}g/mL$ in the control and $278.18{\sim}305.75{\mu}g/mL$ in the Kimchi seasoning with black garlic. The polyphenol compound content increased by increasing the amount of black garlic in the Kimchi seasoning. The polyphenol compound contents gradually decreased during storage period. The flavonoid compound content was 26.18 mg% in the control and 26.80~38.72 mg% in the Kimchi seasoning replaced with 25~75% black garlic. The flavonoid compound contents increased by increasing the amount of black garlic. The flavonoid contents were different from those of polyphenol compounds during storage periods. In the case of DPPH electron donating abilities, DPPH electron donating ability of the control was 84.82%, which showed a lower antioxidative activity than the Kimchi seasoning replaced with black garlic. The electron donating abilities of the Kimchi seasoning replaced with black garlic were increased as the amount of black garlic was increased. In the lipid peroxidation test, the control showed no lipid peroxidation during the storage period. The Kimchi seasoning replaced with black garlic also inhibited lipid peroxidation during storage as in the control. However, it showed lower activity than the control. Reducing power was higher in the Kimchi seasoning replaced with black garlic than in the control. The higher the ratio of black garlic, the higher the reducing power.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.2
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• pp.256-263
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• 2009

For the power system to keep in a stable operating state, sufficient ancillary services must be available to respond to credible contingency events and return the power system to a satisfactory operating state in the case of contingencies as well as blackout events within specified predefined limits. The logical and reasonable bases of valuing and pricing the ancillary services are required to reach the common ground among market participants. The total amount of black start service transactions is quite small compared to the total ancillary service transactions as well as energy market transactions. Black start services must be provided as one of the ancillary services in the deregulated electricity market. In order to procure and remunerate black start services, it is necessary to quantify the value of the black start sources within the power system. In this paper, an approach to assess the value of the black start service is presented based on the cost-of-service solution. Financial simulation of the influence on market participants for the proposed approach on the service is carried out. The cost of the black start service is allocated in accordance with the principle of "causer pays", and the cost is shared by the producers and consumers equally that created the requirement for the service. Under the present electricity market, the mechanism to recover the cost is not implemented, a new approach to the ancillary services to provide incentive for the service providers has to be studied in the near future.

• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.267-272
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• 2021

In this study, Ag was deposited to investigate its applicability as a surface-enhanced Raman scattering substrate after forming a grass-type black silicon structure through maskless reactive ion etching. Grass-structured black silicon with heights of 2 - 7 ㎛ was formed at radio-frequency (RF) power of 150 - 170 W. The process pressure was 250 mTorr, the O₂/SF₆ gas ratio was 15/37.5, and the processing time was 10 - 20 min. When the processing time was increased by more than 20 min, the self-masking of Si_xO_yF_z did not occur, and the black silicon structure was therefore not formed. Raman response characteristics were measured based on the Ag thickness deposited on a black silicon substrate. As the Ag thickness increased, the characteristic peak intensity increased. When the Ag thickness deposited on the black silicon substrate increased from 40 to 80 nm, the Raman response intensity at a Raman wavelength of 1507 / cm increased from 8.2 × 10³ to 25 × 10³ cps. When the Ag thickness was 150 nm, the increase declined to 30 × 10³ cps and showed a saturation tendency. When the RF power increased from 150 to 170 W, the response intensity at a 1507/cm Raman wavelength slightly increased from 30 × 10³ to 33 × 10³ cps. However, when the RF power was 200 W, the Raman response intensity decreased significantly to 6.2 × 10³ cps.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.205-211
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• 2001

We propose a constant inversion black box model of erbium-doped fiber amplifiers (EDFAs) for exact performance predictions for EDFAs operated in the gain-flattened condition. The validity of the newly proposed model was experimentally verified by predicting the performance of EDFAs for the L band, within 1.9% required pump power discrepancy. The role of ion pairing effects on the power conversion efficiency is also discussed. ussed.