• 한국태양에너지학회 논문집
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• 제39권4호
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• pp.41-54
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• 2019

The proportion of solar photovoltaic power generation has steadily increased in the power trade market. Solar energy forecast is highly important for the stable trade of volatile solar energy in the existing power trade market, and it is necessary to identify accurately any forecast error according to the forecast lead time. This paper analyzes the latest study trend in solar energy forecast overseas and presents a consistent comparative assessment by adopting a single statistical variable (nRMSE) for forecast errors according to lead time and forecast technology.

• 한국태양에너지학회 논문집
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• 제37권3호
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• pp.33-45
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• 2017

Crystalline silicon photovoltaic module certification began in 2007. "Renewable Energy Equipment Certification Scheme" was implemented until July 28, 2015. Then, the scheme was changed to "KS Certification Scheme" since July 29, 2015. A total of 2,331 models have been certified by 2016. The proportion of multi crystalline modules in certified products is higher than that of mono crystalline modules, and Korean modules account for 78% of the total certification modules. Chinese solar cells account for the highest percentage of 40% of the total modules and 62.4% of modules certified in 2016 use Chinese solar cells. With the development of technology, module power is continuously increasing, and efficiency is also rising. The average efficiency of mono crystalline module is 0.74% higher than the average of multi crystalline module. As a result of comparing domestic module with Chinese module, the highest efficiency of mono crystalline module and multi crystalline module and the average efficiency of mono crystalline module are higher than those of Chinese module, but the average efficiency of multi crystalline module is similar to that of Chinese module.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.215-221
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• 2023

A rapid and environment-friendly electrochemical sensor to determine the chemical oxygen demand (COD) has been developed. The boron-doped diamond (BDD) thin-film electrode is employed as the anode, which fully oxidizes organic pollutants and provides a current response in proportion to the COD values of the sample solution. The BDD-based amperometric COD sensor is optimized in terms of the applied potential and the solution pH. At the optimized conditions, the COD sensor exhibits a linear range of 0 to 80 mg/L and the detection limit of 1.1 mg/L. Using a set of model organic compounds, the electrochemical COD sensor is compared with the conventional dichromate COD method. The result shows an excellent correlation between the two methods.

• 방사선산업학회지
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• 제6권1호
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• pp.17-21
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• 2012

The effects of gamma ray or electron beam irradiation on herbaceous medicinal plants were investigated in terms of the composition of volatile constituents using the aerial parts or leaves of Artemisia princeps Pamp. cv. Ganghwayakssuk and Artemisia argyi cvs. Namhaeyakssuk and Hwanghaessuk. The composition of volatile constituents in leaves was clearly distinguishable among the three Artemisia cultivars. However, the relative proportions of the major volatile constituents such as 1,8-cineole, ${\alpha}$-pinene, camphene, santolina triene, and artemesia triene, were similarly changed in two or three cultivars by gamma ray or electron beam irradiation. In particular, the proportion of 1,8-cineole was increased up to 1.29- to 1.71-fold in the three cultivars after irradiation with gamma ray. These results suggest that gamma ray or electron beam irradiation can be applied to modulate the composition of volatile constituents in the leaves of Artemisia plants.

• 한국광학회지
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• 제13권4호
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• pp.332-335
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• 2002

가류고무의 접착력을 향상시키기 위해서 엑시머 펄스 레이저 광으로 표면처리를 하였다. 레이저 광 조사 수의 증가에 따라, 접착력은 크게 향상되어, 100회의 조사 수에서 1500 N/m의 가장 큰 값을 얻었다. 또한 에너지 밀도 증가에 대해서도 접착력은 증가하여 에너지 밀도 176 mJ/$cm^{2}$에서 가장 큰 접착력 1500 N/m를 얻게 되었다. 에너지 밀도의 증가에 따라 접착력이 증가하는 것은 표면적의 증가와 관련이 있음을 알았다.

• 전력전자학회논문지
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• 제17권6호
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• pp.516-522
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• 2012

Recently trends of home appliance has been changed in house and the demand for functional refrigerator has been increased. Power consumption of refrigerator accounts for a large proportion in consumer electronics. Also, compressor accounts for most of the power consumption in refrigerator parts. Therefore, this paper proposes a multi-refrigerator system with single compressor & condenser fan in order to reduce energy. To verify the availability of the proposed multi refrigerant system, integration experiment is carried out.

• 신재생에너지
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• 제18권1호
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• pp.35-45
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• 2022

The renewable energy based MG is becoming one of the prominent solutions for greenhouse gas and constructing less power lines. However, how to procure the economics of MG considering the CO₂ emission and utility network impact is one of major issues as the proportion of renewable resource increases. This paper proposes the feasibility study scheme of campus MG and shows that the LCOE and CO₂ emission can be reduced by utilizing the excess power and introducing hydrogen system and plus DR. For this, the three cases: (a) adding the PV and selling excess power to utility, (b) producing and selling hydrogen using excess power, and (c) participating in plus DR are considered. For each case, not only the topology and component capacity of MG to secure economic feasibility, but also CO₂ emission and utility network effects are derived. If an electrolyzer with a capacity of 400 kW participates in plus DR for 3,730hours/year, the economic feasibility is securable if plus DR settlement and hydrogen sale price are more than 7.08¢/kWh and 8.3USD/kg or 6.25¢/kWh and 8.6USD/kg, respectively. For this end, continuous technical development and policy support for hydrogen system and plus DR are required.

• 콘크리트학회논문집
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• 제12권5호
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• pp.13-23
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• 2000

In this study, an flexural test on half-scale spliced PSC-I girder was conducted to verify the efficiency of the long span spliced girder as suggested by the Korean Highway Design Specification. The experimental results showed that the specimens developed a complex failure mode due to flexural-compression and torsional stress. The cracking moment of each girder was higher the experiment than was calulated by the ACI and the ultimate strength were the almost same. To estimate the safety and the structural efficiency of the spliced girder, the proposed Yielding Resistance Index(YRI) and ductility index by American Concrete Institutes were used based on the energy concept. The proposed YRI defined the ratio of crack resisting energy and the total energy calculated from load-displacement relationship. Based on the analysis of YRI and ductility index, the flexural behavior of the spliced girder was found to be efficient. Through the experimental results, the structural behavior of proposed spliced PSC I-type girder for long span bridge was found to be more efficient than the exsisting PSC I-type girders.

• 한국식품영양과학회지
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• 제22권4호
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• pp.367-373
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• 1993

본 연구는 15~16세의 여자 고등학생 7명을 대상으로 4주간 평상시와 같은 생활양식과 식생활 환경하에서 에너지 섭취량(GE)과 체내 에너지 보류량(BE)의 변동을 측정하므로써 (에너지 평형법) 에너지 소비량을 산출하였다. 에너지 섭취량과 대변으로의 에너지 손실량(FE)은 열량계로 측정하였고 소변으로의 에너지 손실량 (UE)은 질소 배설량으로부터 환산하였다. 체내 지방조직량 (FM)은 피부두께를 측정하여 산출한 신체 밀도법에 의하였다. 총 에너지 섭취량에 대한 당질, 단백질 및 지방질의 구성비는 각각 70.1$\pm$1.8%, 12.2$\pm$0.7% 및 17.7$\pm$2.0% 이었다. 총 에너지 섭취량에 대한 대변으로의 에너지 손실율은 2.8%이었다. 대변과 소변으로의 에너지 손실량을 감하여 산출한 1일 1인당 평균 대사에너지량(ME)은 2022 $\pm$50㎉ 이었다. 28일동안의 체성분 변동량으로부터 산출한 체내 총 에너지변동량(BE)은 평균 2400$\pm$950㎉ 가 증가하였다. 1일 1인당 평균 에너지 소비량은 1958$\pm$87㎉로서 체중 kg당 39$\pm$2㎉ 이었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.650-654
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• 1995

In this study, in order to measure energy-absorbing charactistics in collapse test of CFRP thin-walled laminates and interpretate the cause of decreasing age when collapse test is carried out under the environments of high temperatures and hygrothermals, the moisture absorbing behavior according to the variety of orientation angel is observed and collapse characteristics is compared with the influence of high temperatures and hygrothermals. Especially, we supposed to clearly understand reationship between collapse characteristics in proportion to the variety of orientation angel and moisture absorbing. The value of the maximum loading, mean loading,rate of energy absorption energy per unit volume and mass in CFRP thin-walled laminates on the high temperatures and hygrothermals is measured lower than under no moisture absorbing. The maximum collapse loading in dynamic impact test is taken measurement lower than in static collapse test regarding compared with collapse characteristics conformity with the variety of the CFRP circular laminates in high temperatures and hygrothermals. But the absorbed energy per unit mass and volume is almost same and the biggest amount of energy is shown in the CFRP circular laminates with orientation angel of 15 .deg.. Therefore, in the case of use to CFRP circular laminates with axisymmetric mode, CFRP thin-walled structal members with orientation angel of 10 .deg. , 15 . deg. are generally useful.