• Ceramist
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• v.21 no.2
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• pp.75-82
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• 2018

In the photovoltaics (PV) industry, there were many efforts to reduce the cost of production with high efficiency. The single most important cost factor in silicon technology is the wafer, accounting presently for ~35% of the module cost. it was already shown that the solar cell efficiency can be maintained up to the thickness range of $40-60{\mu}m$. The direct production of ultra-thin silicon wafer is very attractive and numerous different techniques, such as electrochemical process, ion implantation, and epitaxial growth, have been proposed and developed in many academic and industrial laboratories.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.60.1-60.1
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• 2010

공동주택에서 태양광발전(PV)을 통한 세대 전기에너지 이용은 모듈 설치 면적의 제약으로 인해 전 세대를 대상으로 활용하기에 현실적으로 어려움이 있다. 특히 남향이나 남동, 남서향으로 위치한 거실 창호를 활용하는 경우에도 결정질 실리콘(crystalline silicon) 태양전지 셀로 인한 실내 음영문제 등으로 건물통합형 태양광발전(BIPV) 시스템의 가시성을 확보하는데 한계가 있다. 따라서 이런 문제점을 극복하고자 투광형 비정질실리콘(amorphous silicon) 태양전지를 이용한 발코니창호/커튼월 BIPV 시스템을 구축하고, 테스트베드를 통한 적용성 평가 검증을 수행하였다. 테스트베드는 KCC 중앙연구소 1층 외부 측창에 결정질 BIPV 모듈(A2PEAK 사(社), 최대 출력 210 Wp, W 2,000 mm ${\times}$ H 1,066 mm)과 10% 및 30% 투광형 비정질 BIPV 모듈(Sharp 사(社) See Through type, 최대 출력 135 Wp/123 Wp, W 1,930 mm ${\times}$ H 1,180 mm)을 각각 설치(남서 $30^{\circ}$, 수직 $90^{\circ}$)하여, 2009년 5월에서 8월 사이 4개월에 걸친 모니터링을 통해 실제 발전량 데이터를 확보, 시스템에 대한 분석을 진행하였다. 분석 결과, 설치용량당 일평균 발전량은 결정질형이 1.46 kWh/kWp, 10% 투광형은 1.10 kWh/kWp, 30% 투광형은 0.73 kWh/kWp을 나타내었다. 10% 투광형과 30% 투광형의 모듈 성능 차이는 크지 않으나 발전량에 있어서는 큰 차이를 보였고, 10% 투광형의 설치용량당 일평균 발전량은 경정질형의 75.2% 수준으로 투광형 비정질실리콘 BIPV 시스템의 창호 적용 가능성을 확인하였다. 특히 세대 거실 창호를 통한 가시성 확보는 기존 결정질 BIPV 창호의 단점을 개선하였다. 건자재 일체화로 구축된 가시성확보 BIPV시스템 창호는 단위 세대별 적용이 쉽고, 공동주택에서 PV 시스템의 설치면적을 극대화시키므로 향후 Zero Energy 공동주택 구축에도 활용성이 클 것으로 기대된다.

• Current Photovoltaic Research
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• v.1 no.1
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• pp.17-26
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• 2013

In contrast to conventional crystalline cells, back-contact solar cells feature high efficiencies, simpler module assembly, and better aesthetics. The highest commercialized cell and module efficiency was recorded by n-type back-contact solar cells. However, the mainstream PV industry uses a p-type substrate instead of n-type due to the high costs and complexity of the manufacturing processes in the case of the latter. P-type back-contact solar cells such as metal wrap-through and emitter wrap-through, which are inexpensive and compatible with the current PV industry, have consequently been developed. In this paper the characteristics of EWT (emitter wrap-through) solar cells and their status and prospects for development are discussed.

• Polymer(Korea)
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• v.30 no.5
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• pp.407-411
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• 2006

The SiC-based ceramic nanopatterns were prepared by placing polydimethylsiloxane (PDMS) mold from DVD master on the spincoated polyvinylsilaeane (PVS) or allylhydridopolycaybosilane (AHPCS) as ceramic precursors to fabricate line pattern via UV-nanoimprint lithography (UV-NIL), and subsequent pyrolysis at $800^{\circ}C$ in nitrogen atmosphere. As the dimensional change of polymeric and ceramic patterns was comparatively investigated by AFM and SEM, the shrinkage in height was 38.5% for PVS derived pattern and 24.1% for AHPCS derived pattern while the shrinkage in width was 18.8% for PVS and 16.7% for AHPCS. It indicates that higher ceramic yield of the ceramic precursor resulted in less shrinkage, and the strong adhesion between the substrate and the pattern caused anisotropic shrinkage. This preliminary work suggests that NIL is a promissing route for fabricating ceramic MEMS devices, with the development on the shrinkage control.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.525-527
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• 1996

Hysteresis current control is one of the simplest techniques used to control currents for high speed drive systems, because of its simplicity of implementation, fast current control response, and inherent peak current limiting capability. However the conventional fixed-band hysteresis control has a variable switching frequency throughout the fundamental period, and consequently the load current harmonics spreaded on the wide frequency range. In this paper, a simple, novel alterative approach is proposed for a variable-hysteresis band current controller which uses feedback techniques to achieve constant switching frequency with good dynamic response. The method is easily implemented in hardware, the resultant controller is easily tuned to a particular load, and has good immunity to variation in PV parameter and dc supply voltage.

• Current Photovoltaic Research
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• v.6 no.1
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• pp.17-20
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• 2018

The dependency of the photovoltaic performance of p-/n-type silicon solar-cells on the metallic contaminant type (Fe, Cu, and Ni) and concentration was investigated. The minority-carrier recombination lifetime was degraded with increasing metallic contaminant concentration, however, the degradation sensitivity of recombination lifetime was lower at n-type than p-type silicon wafer, which means n-type silicon wafer have an immunity to the effect of metallic contamination. This is because heavy metal ions with positive charge have a much larger capture cross section of electron than hole, so that reaction with electrons occurs much more easily. The power conversion efficiency of n-type solar-cells was degraded by 9.73% when metallic impurities were introduced in the silicon bulk, which is lower degradation compared to p-type solar-cells (15.61% of efficiency degradation). Therefore, n-type silicon solar-cells have a potential to achieve high efficiency of the solar-cell in the future with a merit of immunity against metal contamination.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.16-21
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• 2010

It is well-known that Boron-doped Cz Si solar cells suffer light-induced degradation due to boron-oxygen defect which is responsible of a reduction in lifetime and hence efficiency. In this paper, we assume that PV solar cell has been connected with variable load to account the real operating condition and it shows different light-induced degradation of Si solar cell. To evaluate the effect of light-induced degradation for solar cell with various load, Single crystalline solar cells are connected with open and short circuits during light exposure. Isc-Voc curve evaluate light induced degradation of solar cells and the reason is explained as a change for serial resistance. From the results, Electrical characteristics of solar cells show better performance under short circuit conditions, after light exposure.

• KIEAE Journal
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• v.14 no.1
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• pp.67-74
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• 2014

There have distinctly been no the installation criteria and maintenance management of BIPV systems, although the BIPV market is consistently going on increasing. In addition, consideration of the BIPV generation quantity which has been installed at several diverse places is currently almost behind within region in Korea. Therefore, the main aim of this study is to evaluate the BIPV generation and to be base data of reducing rate depending on regional installation angles using PVpro which was verified by measured data. Various conditions were an angle of inclination and azimuth under six major cities: Seoul, Daejeon, Daegu, Busan, Gwangju, Jeju-si for the BIPV system generation analysis. As the results, Seoul showed the lowest BIPV generation: 1,054kWh/kWp.year, and Jeju-si have 5percent more generation: 1,108.0kWh/kWp.year than Seoul on horizontal plane. Gwangju and Daejeon turned out to have similar generation of result, and Busan showed the highest generation: 1,193.5kWh/kWp.year, which was increased by over 13percent from Seoul on horizontal plane. Another result, decreasing rate of BIPV generation depending on regional included angle indicate that the best position was located on azimuth: $0^{\circ}$(The south side) following the horizontal position(an angle of inclination: $30^{\circ}$). And the direction on a south vertical position(azimuth: $0^{\circ}$, an angle of inclination: $90^{\circ}$) then turned out reducing rate about 40percent compared with the best one. Therefore, these results would be used to identify the installation angle of the BIPV module as an appropriate position.

• The Plant Pathology Journal
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• v.29 no.2
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• pp.182-192
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• 2013

Numerous root-associated bacteria (rhizobacteria) are known to elicit induced systemic resistance (ISR) in plants. Bacterial cell-density-dependent quorum sensing (QS) is thought to be important for ISR. Here, we investigated the role of QS in the ISR elicited by the rhizobacterium, Serratia marcescens strain 90-166, in tobacco. Since S. marcescens 90-166 produces at least three QS signals, QS-mediated ISR in strain 90-166 has been difficult to understand. Therefore, we investigated the ISR capacity of two transgenic tobacco (Nicotiana tabacum) plants that contained either bacterial acylhomoserine lactone-producing (AHL) or -degrading (AiiA) genes in conjunction with S. marcescens 90-166 to induce resistance against bacterial and viral pathogens. Root application of S. marcescens 90-166 increased ISR to the bacterial pathogens, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas syringae pv. tabaci, in AHL plants and decreased ISR in AiiA plants. In contrast, ISR to Cucumber mosaic virus was reduced in AHL plants treated with S. marcescens 90-166 but enhanced in AiiA plants. Taken together, these data indicate that QS-dependent ISR is elicited by S. marcescens 90-166 in a pathogen-dependent manner. This study provides insight into QS-dependent ISR in tobacco elicited by S. marcescens 90-166.

• Journal of the Korean Solar Energy Society
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• v.35 no.5
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• pp.57-65
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• 2015

The Potential Induced Degradation(PID) in PV module mainly affected by various performance conditions such as a potential difference between solar cell and frame, ambient temperature and relative humidity. The positive charges as sodium ions in front glass reach solar cell in module by a potential difference and are accumulated in the solar cell. The ions accelerate the recombination of generation electrons within solar cell under illumination, which reduces the entire output of module. Recently, it was generally known that PID generation is suppressed by controlling the thickness of SiNx AR coating layer on solar cell or using Sodium-free glass and high resistivity encapsulant. However, recovery effects for module with PID are required, because those methods permanently prevent generating PID of module. PID recovery method that voltage reversely applies between solar cell and frame contract to PID generation begins to receive attention. In this paper, PID recovery tests by using voltage under various outdoor conditions as humidity, temperature, voltage are conducted to effectively mitigate PID in module. We confirm that this recovery method perfectly eliminates PID of solar cell according to repeative PID generation and recovery as well as the applied voltage of three factors mainly affect PID recovery.