• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.72.1-72
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• 2003

Generally, plants defend themselves against pathogens by structural and biochemical reactions. Defense structures act as physical barriers and inhibit the pathogen from gaining entrance and spreading through the plant. Xanthomonas axonopodis pv glycines, the causal pathogen of bacterial pustule of soybean, causes hypersensitive response (HR). When pepper fruits were inoculated with X. axonopodis pv. glycines, in situ, time-series defense-related structural changes occurred in the inoculated sites. Early responses were programmed cell death (PCD), characterized by condensation and vacuolization of the cytoplasm, condensation of nuclear materials, and fragmentation of the nuclear DNA, which were observed by transmission electron microscopy. Nuclear fragmentation was proven by TUNEL method under confocal laser scanning microscopy and DNA laddering through eletrophoresis. At later stages, plant responses were cell elongation and cell division, forming a periderm-like boundary layer that demarcated healthy tissues from the inoculation sites. Using several stains such as toluidine blue, sudan IV, annexin V, and phloroglucinol-HCl, defense-related materials and structural changes were also examined.

• Current Photovoltaic Research
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• v.5 no.1
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• pp.33-37
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• 2017

Today, photovoltaic power generation mostly uses Si crystalline solar cell modules. The most vulnerable part of the Si solar cell module is that the power generation decreases due to the temperature rise. But, it is widely used because of low installation cost. In the solar market, where Si crystalline solar cell modules are widely used. The CPV (Concentrated Photovoltaic) module appeared in the solar market. The CPV module reduces the manufacturing cost of the solar cell by using non-Si in the solar cell. Also, there is an advantage that a rise in temperature does not cause a drop in power generation. But this requires high technology to install and has a disadvantage that the initial installation cost is expensive compared to normal Si solar cell module. So that we built a testbed to see these characteristics. The testbed was used to measure the amount of power generation in a long-term outdoor environment and compared with the general Si solar cell module.

• Journal of Navigation and Port Research
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• v.31 no.3 s.119
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• pp.229-233
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• 2007

This paper presents the performance of PV(Photovoltaic) system, the design of MPPT(Maximum Power Point Tracker). Output of PV power system is DC, and PV power system is linked to the DC bus. The current(I)-voltage(V) output characteristic of PV cells changes with solar irradiance and cell temperature as parameters. As various PV modules respond differently to each of the parameters cited above. Maximum output of PV modules am be achieved by MPPT(Maximum Power Point Tracker) algorithm This paper includes a discussion on the performance of PV module, MPPT algorithm and the influence of PV module angle.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.3
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• pp.107-116
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• 2005

The paper addresses modeling and analysis of a grid-connected photovoltaic generation system (PV system). PSCAD/EMTDC, an industry standard simulation tool for studying the transient behavior of electric power system and apparatus, is used to conduct all aspects of model implementation and to carry out extensive simulation study. This paper is aimed at sharing with the PSCAD/EMTDC user community our user-defined model for PV system applications, which is not yet available as a standard model within PSCAD/EMTDC. An equivalent circuit model of a solar cell has been used for modeling solar array. A series of parameters required for array modeling have been estimated from general specification data of a solar module. A PWM voltage source inverter (VSI) and its current control scheme have been implemented. A maximum power point tracking (MPPT) technique is employed for drawing the maximum available energy from the PV array. Comprehensive simulation results are presented to examine PV array behaviors and PV system control performance in response to irradiation changes. In addition, dynamic responses of PV array and system to network fault conditions are simulated and analysed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.11
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• pp.901-905
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• 2010

PV module has many power loss factors, and series resistance is the most important elements of them. It is therefore easy to expect the partial shading decrease the lifetime of the semiconductor depletion layer in thin film PV module. Different shading losses could be related with the hot spot which is critical in expecting the reliability issue. In this paper we have modelled the series resistance of the PV module with both different direction of the cell line and shading area of the panel. From the results, thin film a-Si PV module has shown different properties by shading direction.

• Journal of the Semiconductor & Display Technology
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• v.17 no.3
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• pp.10-16
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• 2018

In silicon crystalline PV (Photo Voltaic) industry, PV module or panel electric power is directly related to the companies' profit. Thus, many PV companies have invested and focused on R&D activities to get the higher module power. The main BOM (Bills of Material) on the module consists of PV solar cell, ribbon, EVA (Ethylene-Vinyl Acetate copolymer), glass and back sheet. Based on consistent research efforts on enhancing module power using BOM, there have been increase of around 5 watt per module every year as results. However, there are lack of studies related to enhancing accuracy of measurement. In this study, the enhancing on the metrology is investigated and the improvement shows actually contribution to company's profit. Especially, the measurement issues related to heat and to quasi state of bandgap diagram by EL(Electro Luminescence) are described in this study.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.91-95
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• 2012

본 연구에서는 열충격 시험을 통하여 Cell레벨에서의 효율저하 특성을 분석하였다. 열충격 시험은 PV모듈의 시험 규격인 KS C IEC-61215를 이용하여 보다 가혹한 조건인 $-40^{\circ}C$에서 $120^{\circ}C$의 조건으로 500사이클 수행하였다. I-V 측정을 통하여 효율을 분석한 결과, 열충격 시험 전 13.9%에서 열충격 시험 후 11.0%로 효율이 저하 됐으며, 감소율은 20.9% 나타났다.EL촬영을 통해 표면을 분석한 결과 Ribbon접합부 및 Gridfinger의 손상으로 확인 됐으며, 보다 정확한 효율 저하의 원인을 분석하기 위해 단면분석을 실시한 결과 표면손상으로 확인 되었던 위치의 Cell내부에서도 Crack을 확인 할 수 있었다. 또한 FF값을 분석한 결과 열충격 시험 전 72.3%에서 시험 후 62.0%로 11.8%의 감소율을 보였다. 따라서, 경년 시 나타나는 효율저하는 Cell자체의 소모전력 증가와 외부환경에 의한 표면 손상 및 Cell내부의 Crack에 기인하여 가속된다고 판단된다.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.85-92
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• 2005

One of the most effective methods for utilizing solar energy is to combine thermal solar and optical energy simultaneously using a hybrid panel. Many systems using various kinds of photovoltaic panels have already been constructed. But utilizing solar energy by means of a hybrid panel with concentrator has not been to be attempted yet. Normally if sunlight is directed on the solar cell, and there is no increase in temperature, the absorption energy of each cell will increase per unit area. In a silicon solar cell. however, cell conversion efficiency decreases according to the increasing temperature. Therefore, to maintain cell conversion efficiency under normal condition, it is necessary to keep the cell at operating temperature. we design and make new hybrid panel with cooling system to prevent increasing of temperature on cell, collect effectively thermal energy. We compared performance of new hybrid panel with PV module and thermal panel. We also evaluated conversion efficiency, electric power and thermal capacity and confirmed cooling effect from thermal absorption efficiency.

• Korean Journal of Food Science and Technology
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• v.40 no.2
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• pp.220-227
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• 2008

In this study, polysaccharides were isolated from Korean persimmon vinegar to characterize the polysaccharides existing as soluble forms within traditional Korean fermented beverages, and their immuno-stimulating activities were examined. Three successive chromatographies were used to purify the main polysaccharide in the persimmon vinegar, PV-1b-I, to homogeneity from the crude polysaccharide (PV-0). The molecular mass of PV-1b-I was estimated as 110 kDa and it contained significant proportions of mannose (46.8%), galactose (28.5%) and arabinose (19.1%). PV-1b-I strongly reacted with ${\beta}$-glucosyl Yariv reagent, suggesting the presence of an arabino-3,6-galactan moiety. PV-1b-I also induced high levels of macrophage activation and mitogenicity on murine splenocytes in vitro. The intravenous administration of PV-1b-I significantly augmented NK cytotoxicity against YAC-1 tumor cells. PV-1b-I also showed potent anticomplementary activity in a dose-dependent manner. Finally, C3 activation products were identified by crossed immunoelectrophoresis using anti-human C3 and the anti-complementary activity of PV-1b-I under $Ca^{2+}$-free conditions, suggesting that this PV-1b-I causes complementary activations via both alternative and classical pathways. From these results, one can conclude that Korean persimmon vinegar contains select polysaccharides in addition to healthy components, and these polysaccharides appear to provide immuno-stimulating activities beneficial to human health.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.629-634
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• 2013

This study aims to investigate a new structure for a concentrating photovoltaic (PV) module using a III-V compound semiconductor solar cellto solve the problems of existing concentrating PV modules and to explore a concentrating optical system with a flat structure, which shows remarkable advantages in terms of manufacturing cost, installation, and maintenance. This study should greatly contribute toward the development of concentrating PV modules. This study was performed to achieve an improvement in efficiency and economy and to implement an actual product. A new source of renewable energy is the only way in which countries that cannot produce oil can even emerge as an energy power. Therefore, this work can serve as a fundamental study that will help South Korea grow into a country that is a PV power generation force.