• Current Photovoltaic Research
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• 제9권4호
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• pp.128-132
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• 2021

Advances in screen printing technology have been led to development of high efficiency silicon solar cells. As a post PERx structure, an n-type wafer-based rear side TOPCon structure has been actively researched for further open-circuit voltage (Voc) improvement. In the case of the metal contact of the TOPCon structure, the poly-Si thickness is very important because the passivation of the substrate will be degraded when the metal paste penetrates until substrate. However, the thin poly-Si layer has advantages in terms of current density due to reduction of parasitic absorption. Therefore, poly-Si thickness and firing temperature must be considered to optimize the metal contact of the TOPCon structure. In this paper, we varied poly-Si thickness and firing peak temperature to evaluate metal induced recombination (Jom) and contact resistivity. Jom was evaluated by using PL imaging technique which does not require both side metal contact. As a results, we realized that the SiN_x deposition conditions can affect the metal contact of the TOPCon structure.

• Journal of the Korean Wood Science and Technology
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• 제45권1호
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• pp.1-11
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• 2017

건축물에서 냉방과 난방에 많은 양의 에너지가 소요되고 있다. 건축은 $CO_2$ 발생을 줄이고 에너지 소비 저감을 위하여 냉 난방 부하를 최소화할 필요성이 있다. 그리고 최근 주거문화는 친환경적이고 실내 쾌적성을 중시하는 방향으로 변화하면서 단독주택의 수요가 증가하고 있다. 국내 단독주택의 구조는 크게 조적조, 콘크리트조, 목조 주택으로 구분할 수 있다. 따라서 본 논문은 세 가지 구조방식(조적, 콘크리트, 목조)으로 구성된 동일 면적 단독주택의 냉 난방 부하와 에너지 요구량을 분석하였다. 구조방식별 벽체, 지붕, 바닥 레이어를 구성하였고, 각 레이어의 열관류율(U-value)은 목조 벽체와 같이 스터드를 고려해주기 위하여 PHPP 계산법을 이용하였다. 또한 스터드 유무에 따른 차이를 비교 분석하기 위하여 목조 벽체에서 스터드를 고려하지 않은 경우(비 스터드)를 분석하였다. 분석은 엑셀을 기반으로 자체 개발한 냉 난방 부하 산출 프로그램(CHLC)과 ECO2를 이용하였다. 냉 난방 부하와 에너지 요구량 결과, 목조 구조가 가장 높은 결과를 보였고 콘크리트 구조는 두 번째로 높은 값을 유지하는 것을 확인하였다. 두 구조방식은 에너지소비 측면에서 불리하다고 판단하였다. 결론적으로, 동일한 조건에서의 조적 구조는 다른 구조방식에 비하여 냉 난방 부하 및 에너지 요구량에 있어 유리하며, 목조 구조에서 스터드로 인한 열교를 제외한다면 에너지소비를 줄일 수 있다고 판단되었다.

• 한국지진공학회논문집
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• 제19권4호
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• pp.145-159
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• 2015

A seismic response analysis method for three-dimensional floating offshore structures due to seaquakes is developed. The hydrodynamic pressure exerted on the structure is calculated taking into account the compressibility of the sea water, the fluid-structure interaction, the energy absorption by the seabed, and the energy radiation into infinity. To validate developed method, the hydrodynamic pressure induced by the vibration of a floating massless rigid circular disk is calculated and compared with an exact analytical solution. The developed method is applied to seismic analysis of a support structure for a floating offshore wind turbine subjected to the hydrodynamic pressures induced from a seaquake. Analysis results show that earthquake response of a floating offshore structure can be greatly influenced by the compressibility of fluid, the depth (natural frequencies) of the fluid domain, and the energy absorption capacity of the seabed.

• 대한조선학회지
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• 제19권4호
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• pp.1-10
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• 1982

An experimental investigation on the energy absorption of two staged combined structures is presented, which deals with the plastic collapse test as a series of research on soft bow structure involved in a ship collision. The principle of arithmetic superposition of energy absorption is derived upon experimental analysis and based upon the characteristics of the energy absorptions of component structures. This relationship is related to the further approach toward the design of soft bow.

• 한국시스템다이내믹스연구
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• 제6권2호
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• pp.95-116
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• 2005

The purpose of this study is to analyze the structure of renewable energy market in order to deploy more renewable energy in Korea on the basis of information asymmetry between suppliers and demanders. To attain this purpose we develop the model to analyze and simulate the renewable market using system dynamics. This model is developed not to forecast the accurate size of market but to learn more structure of market using our limited data, mental model and knowledge of market.

• Structural Engineering and Mechanics
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• 제82권6호
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• pp.785-799
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• 2022

The effect of earthquakes in earthquake resistant structure design stages is influenced by the highest ground acceleration value, which is generally a strength-based approach in seismic codes. In this context, an energy-oriented approach can be suggested as an alternative to evaluate structure demands. Contrary to the strength-based approach, the strength and displacement demands of the structure cannot be evaluated separately, but can be evaluated together. In addition, in the energy-oriented approach, not only the maximum effects of earthquakes are taken into account, but also the duration of the earthquake. In this respect, it can be said that the use of energy-oriented earthquake parameters is a more rational approach besides being an alternative. In this study, strength and energy-oriented approaches of earthquake parameters of 11 different periods of single degree of freedom systems were evaluated over 28 different earthquake situations. The energy spectra intended to be an alternative to the traditional acceleration spectra were created using the acceleration parameter equivalent to the input energy. Two new energy parameters, which take into account the effective duration of the earthquake, are proposed, and the relationship between the strength-oriented spectral acceleration parameters and the energy parameters used in the literature is examined by correlation study. According to the results obtained, it has been seen that energy oriented earthquake parameters, which give close values in similar period situations, will be a good alternative to strength oriented earthquake parameters. It was observed that the energy parameters were affected by the effective duration of the earthquake, unlike the strength-based parameters. It has been revealed that the newly proposed energy parameters considering the effective duration give good correlations. Finally, it was concluded that the energy parameters can be used in the design, and the newly proposed effective energy parameters can shorten the analysis durations.

• Steel and Composite Structures
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• 제34권6호
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• pp.891-907
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• 2020

Many studies reveal that during destructive earthquakes, most of the structures enter the inelastic phase. The amount of hysteretic energy in a structure is considered as an important criterion in structure design and an important indicator for the degree of its damage or vulnerability. The hysteretic energy value wasted after the structure yields is the most important component of the energy equation that affects the structures system damage thereof. Controlling this value of energy leads to controlling the structure behavior. Here, for the first time, the hysteretic behavior and energy dissipation capacity are assessed at presence of elliptical braced resisting frames (ELBRFs), through an experimental study and numerical analysis of FEM. The ELBRFs are of lateral load systems, when located in the middle bay of the frame and connected properly to the beams and columns, in addition to improving the structural behavior, do not have the problem of architectural space in the bracing systems. The energy dissipation capacity is assessed in four frames of small single-story single-bay ELBRFs at ½ scale with different accessories, and compared with SMRF and X-bracing systems. The frames are analyzed through a nonlinear FEM and a quasi-static cyclic loading. The performance features here consist of hysteresis behavior, plasticity factor, energy dissipation, resistance and stiffness variation, shear strength and Von-Mises stress distribution. The test results indicate that the good behavior of the elliptical bracing resisting frame improves strength, stiffness, ductility and dissipated energy capacity in a significant manner.

• 한국지열·수열에너지학회논문집
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• 제7권2호
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• pp.1-9
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• 2011

Geothermal heat pumps are known as the most efficient and environment-friendly heating and cooling system, and are also gaining acceptance in buildings. Building energy simulation program, EnergyPlus is used to calculate the energy consumption of residential buildings. This simulated energy consumption is essential for accurate economic analysis. Residential buildings with geothermal heat pumps have complex energy price structure. Electricity rates for residential buildings increase rapidly as the monthly use increases. This complex energy price structure makes the economic analysis complicated. The purpose of this study is to conduct economic comparison of residential geothermal heat pumps and provide a feasible approach in finding their economically feasible capacity.

• 설비공학논문집
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• 제24권2호
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• pp.196-203
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• 2012

Energy foundations and other thermo-active ground structure, energy wells, energy-slab, and pavement heating and cooling represent an innovative technology that contributes to environmental protection and provides substantial long-term cost savings and minimized maintenance. This paper focuses on earth-contact concrete elements that are already required for structural reasons, but which simultaneously work as heat exchangers. Pipes, energy slabs, filled with a heat carrier fluid are installed under conventional structural elements, forming the primary circuit of a geothermal energy system. The natural ground temperature is used as a heat source in winter and a heat sink in summer. The geothermal heat pump system with energy-slab represented very high heating and cooling performance due to the stability of EWT from energy slab. However, the performance of it seemed to be affected by the atmospheric air temperature.

• 한국전기전자재료학회논문지
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• 제23권8호
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• pp.601-604
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• 2010

In this study, the piezoelectric energy harvester was investigated employing the pillar structure with the diameter size of 50~500 um. Usually, the aspect ratio between the height and diameter was related with the piezoelectric performance. High aspect ratio was showed the low electric noise and high piezoelectric properties than low aspect ratio. Therefore, we have selected the Su-8 photo-resist and modified lithography process to manufacture the pillar structure with height above the 250 ${\mu}m$. In this presentation, we will report the process and properties of micro pillar structure based on the PMN-PZT (Pb$(Mg_{1/3}Nb_{2/3})O_3$-PbZrTiO$_3$) materials.