• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.320-320
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• 2010

최근 결정질 태양전지에 관한 연구 중, 후면 공정에 대한 연구가 중요시 되고 있으며 local back contact 구조는 후면 공정에 관한 연구 중 가장 많은 연구가 이루어지고 있는 분야이다. 특히 local back contact이 형성하는 BSF의 폭, 깊이, 간격은 태양전지의 전기적 특성 및 광학적 특성을 결정짓는 결정적인 요인중 하나이다. 하지만 local back contact 형성을 위한 실험에는 많은 시간과 노력이 필요하며, 많은 시행착오를 겪어야 한다. 따라서 2차원 modeling 함수를 통한 TCAD simulation으로 실험하기 이전에 local back contact구조의 태양전지를 만들고 SR로 각 파장별 양자효율의 변화와 전기적 특성을 분석하여 최적화된 local back contact 구조를 제시할 것이다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.49-50
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• 2021

광산 분야 등의 채굴을 위한 천공 과정에서 현재 진행 중인 천공 위치의 실시간 측정이 요구되는데 이를 위해 드릴 후면에 부착된 센서 정보를 로드 파이프를 통해 지상으로 전송할 수 있는 통신방식을 제안하였다. 드릴 후면에 장착된 센서에서 검출된 신호는 송신부에서 변조를 통해 로드 파이프로 전송하고, 수신부에서는 이에 대응되는 복조 과정을 통해 센서 데이터를 추출하였다. 제안된 방법의 검증을 위해 설계된 장치를 사용하여 실험을 수행하였으며, 실험 결과 제안된 방법에 의한 데이터 송수신이 정상적으로 동작함을 확인하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.353-354
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.151-152
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• 2013

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.230-230
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• 2007

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.119-128
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• 2015

This study investigates the wave pressure characteristics of the pile-supported breakwater with single or double perforated walls through 2-D hydraulic experiments and the measured wave pressures are compared to those of wave pressures by Goda's formula. For single chamber, the measured wave pressures in the front wall and rear wall decreased to about 25% and 30%, respectively, compared to those of wave pressures by Goda's formula. Also, the decrease in the wave pressures for double chamber were about 27%, 53%, and 64% in the front wall, middle wall, and rear wall, respectively. It was found that the pile-supported breakwater with double perforated walls was more efficient than the single chamber due to wave dissipation effects of double slit walls with horizontal slits.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2317-2328
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• 2013

In this study, the effect of wave chamber slab on wave pressure along the first and second wall of the perforated caisson breakwater was investigated by performing physical experiment. The experiment was performed without and with the wave chamber slab of the perforated caisson by varying the front wall porosity. The discrepancy in magnitudes of the measured wave pressure along the both walls of the perforated caisson was apparent according to the existence of the wave chamber slab as significantly greater pressures were acquired for all the test cases when the wave chamber was closed upward by the slab. As a result, the magnitudes of the total wave force calculated by integration of the measured wave pressure also were much larger for the caisson breakwater having the wave chamber slab, exceeding the value based on the well known Takahashi's formula (Takahashi and Shimosako, 1994). With respect to the porosity of the front wall, meanwhile, higher pressures were obtained with a larger porosity, at both the first and second wall of the breakwater.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.72.2-72.2
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• 2010

Nowadays, the crystalline Si Solar cell are expected for economical renewable energy source. The cost of the crystalline Si solar cell are decreasing by improvement of its efficiency and decrease of the cost of the raw Si wafers for Solar cells. This Si wafer based crystalline Si solar cell is the verified technology from several decade of its history. Now, I will introduce one method that can be upgrade the efficiency by using simple and economical method. The name of this method is Rear Side Etching(RSE). The purpose of rear side etching is the elimination of n+ layer of rear side and increase of the flatness. The effects of rear side etching are the improvement of Voc and increase of efficiency by reducement series resistance and forming of uniform BSF. The experimental procedure for rear side etching is very simple. After anti-reflection coating on solar cell wafer, Solar cell wafer is etched by the etching chemical that react with only rear side not front side. This special chemical is no harmful to anti-reflection coating layer. It can only etched rear side of solar cell wafer. We can use etching image by optical microscope, minority carrier life time by WCT 120, SiNx thickness and refractive index by ellipsometer, cell efficiency for the RSE effect measurement. The key point of rear side etching is development of etching process condition that react with only rear side. If we can control this factor, we can achieve increase of solar cell efficiency very economically without new device.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.91.1-91.1
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• 2010

There are some methods for increasing efficiency of crystalline silicon solar cells. Among them, It is important to reduce the recombination loss of surface for high efficiency. In order to reduce recombination loss is a way to use the BSF(Back Surface Field). The BSF on the back of the p-type wafer forms a p+layer. so, it is prevented to act electrons of the p-area for the rear recombination. As a result, the leakage current is reduced and the rear-contact has a good Ohmic contact. therefore, open-circuit-voltage and Fill factor(FF) of solar cells are increased. This paper investigates the formation of rear contact process comparing Aluminum-paste(Al-paste) with Aluminum-Metal(99.9%). It is shown that the Aluminum-Metal provides high conductivity and low contact resistance of $21.35m{\Omega}cm$ using the Vacuum evaporation process but, it is difficult to apply the standard industrial process because high Vacuum is needed and it costs a tremendous amount more than Al-paste. On the other hand, using the Al-paste process by screen printing is simple for formation of metal contact and it is possible to produce the standard industrial process. however, it is lower than Aluminum-Metal(99.9) of conductivity because of including mass glass frit. In this study, contact resistances were measured by 4-point prove. each of contact resistances is $21.35m{\Omega}cm$ of Aluminum-Metal and $0.69m{\Omega}cm$ of Al-paste. and then rear contact have been analyzed by Scanning Electron Microscopy(SEM).

• Journal of the Korean earth science society
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• v.27 no.1
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• pp.61-72
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• 2006

Numerical studies on the influence of interaction between atmosphere and ocean on the variation of Karman vortex at the lee side of Jeju Island were carried out. Karman vortex tends to be occurred at limited height associated with Hanla mountain. And we can find clear Karman vortex at 900 hPa height in this study. One big vortex cell occurred at lee side of Jeju Island in the begging stage of its development and the cell was divided into three small cells as time goes by. And the strength and lifetime of small vortexes depend on the distribution of SST (Sea Surface Temperature). Weak gradient of SST makes long-lasting Karman vortex but produces weak potential vorticity at lee side of Jeju-do in comparison with the vortex under strong SST gradient. Strong SST gradient also increases not only the mixing depth but also the mixing ratio at lower level of troposphere. And the increased atmospheric mixing decreases the mechanical forcing due to isolated topography. Then the strength of Karman vortex at the lee side of Jeju Island becomes weak under strong gradient of SST. Thus the evolution of Karman vortex is closely related to distribution of SST around the isolated island.