• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.32-53
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• 2022

Although lithium-ion batteries are currently the most reliable power supply system for various mobile applications, further improvement in energy density is still required as the need for batteries in large energy-consuming devices is rapidly growing. However, in the anode, the most widely commercialized graphite-based anode materials almost face theoretical limitations. In addition, sodium-ion batteries have been actively studied to replace expensive charge carriers with cheaper ones. Accordingly, conversion-based materials have been extensively studied as high-capacity anode materials in both lithiumion batteries and sodium-ion batteries because their theoretical capacity is twice or thrice higher than that of insertion-based materials. This review will provide a comprehensive understanding of conversion-based materials, including basic charge storage behaviors, critical drawbacks that should be overcome, and practical material design for high-performance.

• 전력전자학회논문지
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• 제18권3호
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• pp.270-278
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• 2013

This paper proposes a control method for high voltage direct current(HVDC) with modular multilevel converter (MMC) under unbalanced voltage conditions considering the submodule(SM)'s current capacity and circulating current. It is aimed to propose a control method in which the current peak value does not exceed the maximum value of HVDC-MMC by considering the current capacity of the SM under unbalance voltage conditions. And it analyzes the effect of the unbalanced voltage on circulating currents in MMC and then proposes a control method considering each component of circulating currents under unbalanced voltages. The effectiveness of the proposed controlling method is verified through simulation results using PSCAD/EMTDC.

• 한국태양에너지학회 논문집
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• 제25권3호
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• pp.47-52
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• 2005

Normally if sunlight is directed on a solar cell without any increasing in temperature, the amount of absorption energy per unit area of each cell is increasing. In a silicon solar cell. however, cell conversion efficiency decreases with the increase of temperature. Therefore, to maintain cell conversion efficiency under normal condition, it is necessary to keep the cell at operating temperature. We tried to design and make new hybrid panel with cooling system to prevent increasing of temperature on cell, collect and use thermal energy more effectively. We compared performance of this new hybrid panel with current thermal panel. We also evaluated conversion efficiency, thermal capacity and confirmed cooling effects from thermal absorption efficiency.

• Advances in Energy Research
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• 제3권3호
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• pp.143-155
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• 2015

The Nile blue has been used as a photosensitizer with Arabinose as a reductant in photogalvanic cell for optimum conversion efficiency and storage capacity. Reduction cost of the photogalvanic cell for commercial utility. The generated photopotential and photocurrent are 816.0 mV and $330.0{\mu}A$ respectively. The maximum power of the cell is $269.30{\mu}W$ where as the observed power at power point is $91.28{\mu}W$. The observed conversion efficiency is 0.6095% and the fill factor 0.2566 has been experimentally found out at the power point of the photogalvanic cell, whereas the absolute value is 1.00. The photogalvanic cell so developed can work for 120.0 minutes in dark if it is irradiated for 200.0 minutes that is the storage capacity of photogalvanic cell is 60.00%. The effects of different parameters on the electrical output of the photogalvanic cell have been observed. A mechanism has also been proposed for the photogeneration of electrical energy.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2002년도 추계학술발표대회
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• pp.301-306
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• 2002

In Japan, the vacancy rates of office buildings have been at high in big cities since 1992. This problem is especially acute in Tokyo, where it is estimated that over 2.27 million square meters of office floor area will be oversupplied in 2003: big urban redevelopment projects will be completed in 2003. Under these circumstances, International Cooperative Research and Development on Sustainable Urban Management by Conversion of Buildings, called “SUMCOB”, has been carried out. This research aims to regenerate urban areas by converting redundant offices into flats, although instances of conversion are still very few in Japan. This paper introduces part of current results by SUMCOB, and discusses legal problems with conversion and basic capacity of vacant offices in Tokyo. It has been confirmed that there are no constraints concerned with Real Estate Registration Law (although it requires the change of the registration after conversion). and City Planning Law. However, some criteria are incompatible with Building Standard Law and Fire Service Law if the use of the building is changed from offices to flats. Typical incompatibility between offices and flats is lightening. If the buildings do not satisfy criteria for flats, the cost of renovation works for conversion will increase. To examine the basic capacity of vacant office buildings for conversion, field surveys in Tokyo have carried out at three areas: Kodenmacho (Chuo-ku), Toranomon (Minato-ku), and Iwamonocho (Chiyoda-ku). They are typical office areas that are included in center core of Tokyo. In Chuo-ku, the oldest commercial area in Tokyo, textile merchants have been located their headquarters. In Minato-ku, many rental office buildings have been located and several large scale redevelopments are advancing. Chiyoda-ku includes Marunouchi area, which is the prime office area in Japan. Thirty percent of the buildings in survey areas suffer from over twenty percent vacant floor rate, and fifty five percent were constructed before 1990. Especially most of buildings over forty percent vacant floor rate were constructed in 1980s. Vacant office problems haven't been seen in old buildings in Tokyo yet. The number of dwelling units made from office space will influence the conversion scheme. Seventy percent of the office buildings in survey areas have floor area of less than two hundred square meters. If they have been subdivided into two bedrooms type or three bedrooms type, the number of dwelling units in a floor would be less than three. The difficulty of conversion planning derives from frontage size, depth size, and their proportion. The five categories are proposed to grasp actual requirements for converting offices into flats.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.383-386
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• 2009

Contract power conversion factor which is applied to estimate contract power of industrial customers is an important standard to calculate transformer capacity. This paper shows a reasonable contract power conversion factor, that was made by the systematic and statistical way considering actual conditions, such as investigated contract power and peak power for the last 5 years of each customer for industrial customers as to AMR system. In this dissertation, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum. minimum and thus it was carried the linear and nonlinear regression analysis. Therefore, this paper compared characteristics for a contract power conversion factor which is applied to calculate contract power with characteristics for a regression model for customers which maximum utilization factor of transformer is more than 60%.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.293-296
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• 2008

Contract power conversion factor which is applied to estimate contract power of general customers IS an important standard to caculate transformer capacity. This paper shows a reasonable contract power conversion factor, that was made by the systematic and statistical way considering actual conditions, such as investigated contract power and peak power for the last 5 years of each customer for 132 office building customers as to AMR system. In this dissertation, it is necessary to analyze the key features and general trend from the investigated data. It made an analysis of the feature parameters, such as average, standard deviation, median, maximum, minimun and thus it was carried the linear and nonlinear regression analysis. Therefore, this paper compared characteristics for a contract power conversion factor which is applied to calculate contract power with characteristics for a regression model for customers which maximum utilization factor of transformer is more than 60%.

• 태양에너지
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• 제12권3호
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• pp.126-136
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• 1992

In this paper an EGD generator of small capacity with the operating gases of $O_2,\;N_2$ and air is made and the electric characteristics in relation to energy conversion range length, corona current and gas pressure are investigated. The results are as follows: 1. There is a critical value in conversion range length for maximum open voltage and the critical value increases with fluid velocity. 2. The open voltage increases approximately linearly with corona current. 3. There is a critical value in the gas pressure for maximum open voltage and this pressure of gas decreases with fluid velocity in constant conversion range length.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1208-1211
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• 2009

This study compares and contrasts the market size, growth rates, business cycles, supply and demand of the of the FPD and Photovoltaic (PV) industries. Using historic, market metric, cycle, capacity and other comparative analysis techniques, implications for implementing effective business strategies are formed.

• 한국통신학회논문지
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• 제35권11B호
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• pp.1596-1606
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• 2010

본 논문에서는 산재-부분-제한영역 파장 변환 방식의 파장분할다중화 광통신망의 불통 확률을 정확하게 계산할 수 있는 수학적 성능분석 모형을 제안하고, 이를 기반으로 파장 변환기를 효율적으로 배치하는 파장 변환기 배치 알고리듬을 제시한다. 제안하는 성능분석 모형은 파장 변환기의 제한된 파장 변환 영역으로 발생하는 영역 불통(Range Blocking)과 파장 변환기의 개수 제약으로 발생하는 용량 불통(Capacity Blocking)을 이론적으로 도출하는 최초의 성능분석 모형이다. 유럽 광통신망에서 수행한 시뮬레이션 결과를 통해 제안하는 성능분석 모형이 광통신망의 불통확률을 정확히 예측함을 보인다. 또한, 기존에 알려진 산재 파장 변환 방식, 부분 파장 변환 방식, 또는 제한영역 파장 변환 방식들과 비교할 때, 이들을 효율적으로 결합한 산재-부분-제한영역 파장 변환 방식이 최소의 파장 변환 비용으로 주어진 광통신망의 불통 성능을 달성할 수 있음을 보인다.