• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.143-146
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• 2009

One of the most important issues of crystalline silicon solar cell is minimizing reflectance at the surface. Laser texturing is an isotropic process that will sculpt the surface of a silicon wafer, regardless of its crystallographic orientation. We investigated surface texturing process using Nd-YAG laser ($\lambda$=1064 nm) on multi-crystalline silicon wafer. Removal of slag formed after the laser process was performed using acid solution (HF : $HNO_3$ : $CH_3COOH$ : DI water). The reflectance and carrier lifetime of the samples were measured and analyzed using UV-Vis spectrophotometer and carrier lifetime tester. It was found that the minimum reflectance of the samples was 16.39% and maximum carrier life time was $21.8\;{\mu}s$.

• Transactions on Electrical and Electronic Materials
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• 제4권5호
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• pp.10-14
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• 2003

A low-cost, large area, random, maskless texturing scheme independent of crystal orientation is expected to have significant impact on terrestrial photovoltaic technology. We investigated silicon surface microstructures formed by reactive ion etching (R IE) in Multi-Hollow cathode system. Desirable texturing effect has been achieved when radio-frequency (rf) power of about 20 Watt per one hollow cathode glow is applied for our RF Multi -Hollow cathode system. The black silicon etched surface shows almost zero reflectance in the visible region as well as in near IR region. The etched silicon surface is covered by columnar microstructures with diameters from 50 to 100 nm and depth of about 500 nm. We have successfully achieved 11.7 % efficiency of mono-crystalline silicon solar cell and 10.2 % for multi-crystalline silicon solar cell.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2015년도 춘계학술대회 논문집
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• pp.43-44
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• 2015

Electrodeposited Ni and Ni-SiC composite coatings were prepared on Cu substrates by using the Ni-Sulfamate electrolytic bath. Thus prepared samples were subjected for the two different types of post surface modification techniques; i.e. Laser Surface Texturing (LST) and Ultrasonic Nano Surface Modification (UNSM), respectively in order to investigate their effects on surface and interface related properties of the coatings. Hemispherical dimples, with 80 to 200 um dimple spacing, were created and examined on the surfaces of the materials studied. The results revealed that micro-surface texturing with 150 um dimple spacing considerably improved the coefficient of friction. Dimple spacing accuracy and incorporated second phase ceramic particles both contributed significantly to reduction in coefficient of friction. On the other hand, application of UNSM considerably modified the surface topography, led to increase the Vickers microhardness, and reduced the wear and coefficient of friction as compared to non UNSM treated Ni and Ni-SiC samples.

• 공업화학
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• 제24권1호
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• pp.31-37
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• 2013

텍스쳐링에 의해 실리콘 웨이퍼의 표면반사율을 감소시키는 것은 실리콘 태양전지의 효율향상을 위해 매우 중요한 공정이다. 본 연구에서는 에칭속도 제어를 위해 촉매제를 포함한 산 용액으로 텍스쳐링 처리한 웨이퍼의 표면효과와 그 태양전지 특성을 평가 고찰하였다. 텍스쳐링 전 $HNO_3-H_2O_2-H_2O$ 용액의 전처리는 표면반사율의 초기 저감효과를 가져왔다. 이는 산화특성에 의해 유기 불순물이 제거되고 텍스쳐링을 위한 핵의 생성에 기인한다고 할 수 있다. 이후 공정에서 불산/질산 용액에 인산 및 초산과 같은 완충제를 첨가한 혼합용액을 제조하고, 적정 농도 조합과 그 처리시간의 최적화를 통해 개선된 텍스쳐링 효과를 얻을 수 있었으며 이 효과는 표면반사율 감소를 통해 확인할 수 있었다. 이렇게 제조된 실리콘 웨이퍼에 반사방지막 코팅 후 태양전지를 제작하여 그 변환효율을 측정한 결과 16.4%의 양호한 특성을 나타냈다. 이는 개선된 텍스쳐링 처리에 의해 저감된 표면특성에 의한 단락전류의 증가에 기인한 것으로 추정된다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.349-352
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• 2004

4D-CAD 시스템에 대한 공사관리 도구로서의 활용가능성이 제기되기 시작한 것은 1990년대 후반이후의 일이다. 현재까지 몇몇 4D 시스템틀이 개발 $\cdot$ 적용되고는 있으나, 상용화 및 보편화를 위한 해결되어야 할 다수의 문제점들을 가지고 있다. 특히 자연지형과 계획시설물의 형상을 함께 표현하여야 하는 토목시설물에 대한 4D 시스템 구현에 있어서는 더 많은 해결되어야할 과제들이 존재하고 있다. 토목시설물에 대한 4D 시스템 구현에 있어서의 주요문제점 중 하나는 계획 시설물의 3차원 형상을 그와 접하고 있는 자연지형과 함께 표현할 수 있는 3D 모델을 생성하는 작업량의 방대성이다. 현재까지 이러한 작업은 대부분 수작업으로 진행되어 왔으나, 본 연구에서는 수치지도로부터 얻어지는 지형 삼각망과 계획단면으로부터 생성될 수 있는 계획삼각망을 자동으로 합성할 수 있는 방법론을 제안하며, 더 나아가 양삼각망 간의 합성과정을 생략하고 4D 모델을 구현학 수 있는 방안으로서 VRML의 멀티텍스처링 (multi-texturing) 기법을 적용하는 방법론을 각각 제안하고, 실제 4D 시스템의 구성기능으로서 적용하였다. 이러한 3D 모델 생성의 간편화 기법은 토목시설물에 대한 4D 시스템의 대중화 및 보편화를 위한 핵심기술로서 활용될 수 있을 것으로 판단된다.

• 한국재료학회지
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• 제20권12호
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• pp.649-653
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• 2010

In this paper, double texturization of multi crystalline silicon solar cells was studied with laser and reactive ion etching (RIE). In the case of multi crystalline silicon wafers, chemical etching has problems in producing a uniform surface texture. Thus various etching methods such as laser and dry texturization have been studied for multi crystalline silicon wafers. In this study, laser texturization with an Nd:$YVO_4$ green laser was performed first to get the proper hole spacing and $300{\mu}m$ was found to be the most proper value. Laser texturization on crystalline silicon wafers was followed by damage removal in acid solution and RIE to achieve double texturization. This study showed that double texturization on multi crystalline silicon wafers with laser firing and RIE resulted in lower reflectance, higher quantum yield and better efficiency than that process without RIE. However, RIE formed sharp structures on the silicon wafer surfaces, which resulted in 0.8% decrease of fill factor at solar cell characterization. While chemical etching makes it difficult to obtain a uniform surface texture for multi crystalline silicon solar cells, the process of double texturization with laser and RIE yields a uniform surface structure, diminished reflectance, and improved efficiency. This finding lays the foundation for the study of low-cost, high efficiency multi crystalline silicon solar cells.

• Current Photovoltaic Research
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• 제5권1호
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• pp.25-27
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• 2017

Nanoscale textured black silicon has attracted intensive attention due to its great potential as applications in multicrystalline silicon-based solar cells. It absorbs sunlight over a broad range of wavelengths but introduces large recombination centers, non-uniform doping into cell. In this study, we present a metal-assisted chemical etching technique plus alkaline etching process to fabricate nanoscale pyramid structures with optimized condition. To make the structures, silver nanoparticles-loaded mc-Si wafer was submerged into $H_2O_2/HF$ solution first for nanohole texturing the wafer and textured wafer etched again with KOH solution for making nanoscale pyramid structures. The average reflectivity (350-1050 nm) is about 8.42% with anti-reflection coating.

• 한국염색가공학회지
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• 제13권2호
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• pp.49-49
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• 2001

Interlace texturing is very useful method to make compound yarns for new synthetic fabrics. In this study, we make the compound yarns for peach skin fabric by interlace texturing method. This study surveys relationship between physical properties of interlace textured yarns and process conditions such as air pressure, yarn tension and take-up speed. Nip density, tensile properties and multi-step shrinkage of the various specimens were discussed with process conditions.

• 한국염색가공학회지
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• 제12권5호
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• pp.273-279
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• 2000

Interlace textured yarn was developed in order to increase weaving process efficiency. Today, interlace texturing is very useful method of manufacturing the high added value compound yarns for new synthetic fabrics. In this research, new silky type high added value compound yarns were. manufactured by interlace texturing technology and tested their properties. The object of this research is to investigate the relationship between interlace textured yarn properties and processing parameters that is air pressure, yarn tension and take-up speed. The original filament yarns used were TTD(Thick & Thin Semi-Dull) 110d/72f and SCD(Semi-Dull Cation Dyeable) 75d/36f. 27 specimens were manufactured and tested for their physical properties-nip density, tensile properties, multi-step shrinkage test and surface structure by SEM. The air pressure was main process condition to change properties of interlace textured yarns. And interlace textured process had influence on weaving preparation process, weaving, knitting and so on. It has some influence on shrinkage properties of dyeing and finishing processes.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.182-183
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• 2014

Hemispherical dimples with diameter, ø=$60{\mu}m$ and depth, d= $30{\mu}m$ were created on the metal and ceramics surfaces using INYA 10 watt Laser of 1064 nm wavelength. This study reports the influence of dimple pitch on friction and wear behavior rather than dimple size, depth and density. LST was performed on the specimens with dimple pitch and density in the range of 80 to-$200{\mu}m$ and 44 to 7 %, respectively. Surface topography was analyzed by using roughness measurement, scanning electron microscopy (SEM), and optical microscopy. Friction and wear characteristics were analyzed on textured surfaces at lubricating environment to observe the effect of surface texturing on reduction of friction and wear. Reduction on coefficient of friction was achieved by more than 70% due to the dual behavior of dimples as wear (debris) traps and lubricant reservoirs. Wear reduced significantly for the textured surface as compared to the polished surface. Moreover, the friction coefficient of the textured specimens reduced with increasing load and speed which may be attributed to the transition of lubrication regime.