• Analytical Science and Technology
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• v.33 no.5
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• pp.215-223
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• 2020

The objectives of the present study were to assess the oxidative stability of South Korean n-3 (omega-3 fatty acid) supplements carried out from 2018 to 2019 and evaluate the influence of product characteristics on oxidative safety. A total of 76 n-3 supplements were analysed for oxidation safety by four markers, including acid value (AV), primary oxidation (peroxide value, PV), secondary oxidation (p-anisidine value, pAV) and total oxidation value (TOTOX). Among the supplements tested, 5.3 %, 55.3 %, 28.9 % and 46.1 % exceeded the international voluntary recommended levels for AV, PV, pAV and TOTOX, respectively. Purity (%) of products, remainder of expiration date (suggested shelf life), package in press through package (PTP) and products with additives had statistically significant differences oxidation assessment levels (p < 0.05). In addition, n-3 group found in Algae oil had significantly lower AV levels than the group that did not, and product with Alaska pollack oil, had significantly higher pAV levels than without group (p < 0.05). The high oxidation status of South Korean n-3 products in the present study could not be considered a public health problem right now. However, the levels of oxidation may affect a lot the efficacy and safety of using n-3 supplements. Thus, current oxidation safety limits should be reestablished by regulatory bodies to ensure the safety and efficacy of n-3 supplements, so that the standards could be applied to the products available to consumers.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.269-273
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• 1999

Combination of mental stress task with noise background is a traditional tool employed in psychophysiology. However, intensity of background noise is a factor affecting both performance on test and psychophysiological responses associated with stress evoked by mental load in noisy environment. In the current study on 7 subjects we analyzed the influence of white noise (WN) intensity (55, 70, and 85 dB[A] ) on psychophysiological responses during word recognition test performed on noise background. There were recorded following physiological variables: electrodermal activity (EDA) , namely, skin conductance level (SCL), skin conductance response (SCR) amplitude (SCR-A), rise time and total number of SCRs (N-SCR); cardiovascular activity, e.g., heart rate (HR), respiratory sinus arrhythmia (RSA) index, pulse transit time (PTT), finger pulse volume (PV), skin temperature (SKT) and respiratory activity, such as respiration rate (RESP-R) and inspiration wane amplitude (RESP-A) during baseline resting state and 40 s long performance on 3 similar Korean word recognition tests with different WN intensity (55, 70, and 85 dB). Electrodermal responses (SCR-A, SCL, N-SCR) demonstrated gradual increment with increased intensity of noise, and this increase of response magnitude with higher intensity of noise was typical also for r skin temperature (phasic SKT decrease) and pulse volume (phasic and tonic PV decrease). However, some cardiovascular and respiratory responses did not exhibit same tendency of gradual increase of reactivity , namely HR, as well as RESP-R and RESP-A showed decrement of response magnitudes. Important finding in terms of cardiovascular reactivity was that 55 and 70dB evoked similar profiles, while 85dB WN resulted in significantly different profile of reactions, suggesting that there exists a threshold level after which intensive auditory stimulation elicits psychophyslological responses pattern of different quality. There are discussed potential autonomic mechanism involved in mediation of observed physiological responses.

• New & Renewable Energy
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• v.9 no.2
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• pp.30-39
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• 2013

Multi-crystalline silicon solar cells is not exist a specific crystal direction different from single crystalline silicon solar cells. In functional materials, therefore, isotropic wet etching of mc-Si solar cell is easy the acid solution rather than the alkaline solution. The reflectance of wet texturing process is about 25% and the reflectance of RIE texturing process is achieved less than 10%. In addition, wet texturing has many disadvantages as well as reflectance. So wet texturing process has been replaced by a RIE texturing process. In order to apply BIPV, RIE and wet textured multi-crystalline silicon solar cell modules was manufactured by different kind of EVA sheet. Moreover, in case of BIPV, the short circuit current characteristics according to the angle of incidence is more important, because the installation of BIPV is fixed location. In this study, we has measured SEM image and I-V curve of RIE and wet textured silicon solar cell and PV module. Also we has analyzed quantum efficiency characteristics of RIE and wet textured silicon solar cell for PV modules depending on incidence angle.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.17-22
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• 2011

There are some degradation factors for amorphous silicon solar cells. Light inducing is one of the factor that explained by Staebler-Wronski effect. Also, hotspot heating could be the reason that makes amorphous silicon solar cell degrade. Hotspot heating is occurred when a solar cell is shaded so this work is investigated into two types of shading condition and how these affect to solar cell differently. Reduced irradiance for whole cell and partially shaded as 0($W/m^2$) while the other part of cell is soaking as 1000($W/m^2$) of irradiance are two conditions that are experimented. The two types of shading show different characteristics of degradations. The result shows that partially shaded cell dropped maximum powerless and slower. Also sudden drop points have shown that should be concerned to decide the number of cells for a string. Otherwise, the current through a shaded cell might flow more than cell's capability. It makes cell and module damaged. This work would help to manufacture modules.

• Current Photovoltaic Research
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• v.10 no.2
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• pp.56-61
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• 2022

Recently, the expansion of the domestic solar market due to the promotion of eco-friendly and alternative energy-related policies is promising, and it is expected to lead the high-efficiency/high-power module market based on M10 or larger cells to reduce LCOE, 540-560W, M12 based on M10 cells Compared to the existing technology with an output of 650-700W based on cells, it is necessary to secure competitiveness through the development of modules with 600W based on M10 cells and 750W based on M12 cells. For the development of high efficiency/high-power n-type bifacial, it is necessary to secure a lightweight technology and structure due to the increase in weight of the glass to glass module according to the large area of the module. Since the mechanical strength characteristics according to the large area and high weight of the module are very important, design values such as a frame of a new structure that can withstand the mechanical load of the Mechanical Load Test and the location of the mounting hole are required. In this study, a structural analysis design model was introduced to secure mechanical reliability according to the enlargement of the module area, and the design model was verified through the mechanical load test of the actual product. It can be used as a design model to secure the mechanical reliability required for PV modules by variables such as module area, frame shape, and the location and quantity of mounting holes of the structural analysis model verified. A relationship of output drop can be obtained.

• Current Photovoltaic Research
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• v.11 no.4
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• pp.134-143
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• 2023

Efforts are being made to respond to global warming. Interest in and demand for the private sector-led RE100 campaign is also increasing. Self-built solar power generation, one of the implementation tools for RE100, is not expanding. However, it can be an economical means of implementation in the long run. In this study, we intend to analyze the impact on the optimal ratio of self-solar power generation using HOMER simulation. OPR defines the optimal solar power generation ratio and looks into what changes there are in the optimal solar power ratio when self-power consumption increases and external power purchase price changes. As a result, the optimal rate of self-solar power generation has a low impact even if self-power consumption increases. As the external power unit price increases, the optimal ratio increases, and at a power unit price of 100 KRW/kWh, OPR is 24%; at 200 KRW/kWh OPR is 31%; and at 300 KRW/kWh OPR is 34%. This shows that the electricity price replaced during the life cycle has a high impact on the economic feasibility of solar power generation. However, when the external power unit price reached a certain level, the increase in OPR decreased. This shows that it is difficult for domestic companies to achieve RE100 based on the economic feasibility of solar energy alone. Therefore, efforts are needed to supply renewable energy in the public sector.

• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.665-665
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• 2005

The existing DSP for utility interactive photovoltaic generation system control generally uses floating point process type. Because it is easy to use for number crunching, however, it is too late and too expensive. Fixed point process DSP TMS320F2812, has high control speed and is rather inexpensive. A very complicated real system can be simulated using hardware-in-the-loop (HIL) system in a virtual environment Therefore, HIL system can speed up research and development process with a little effort. Also current DSP for utility interactive photovoltaic generation system adopts floating point process type, which is easy to use for number crunching. However, fixed point process DSF, TMS320F2812, has high control speed and is rather inexpensive. This paper presents more efficient method for MPPT control using TMS320F2812 along with HIL System.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.139.2-139.2
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• 2011

Compared with a traditional power system of electricity providers, distributed power systems consist of power suppliers which are small and demand-oriented. Each small power supplier tends to utilizes renewable energy sources such as solar and wind power. It is because that home renewable energy systems do not need a large scale infrastructure which is required for traditional power plants. In this work we study an economic feasibility of such a renewable energy source. We describe how renewable power generation works and what it brings in terms of economic benefits. Also, we analyze limitations by the current policy and their possible solutions.

• Current Photovoltaic Research
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• v.3 no.2
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• pp.45-49
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• 2015

In the past few decade's researchers, scientists, engineers of photovoltaic (PV) industry are working towards low cost high efficiency Si solar cells. Over the last decade the interest in back contact solar cell has been acquiring as well as a gradual introduction to industrial applications is increasing. As an alternative to conventional solar cells with a front and rear contact, the back-contact cells has remained a research topic. The aim of this work is to present a comprehensive summary of results incurred in the back contact back junction solar cells such as interdigitated back-contact (IBC), emitter wrap-through (EWT) and metallization wrap-through (MWT) over the years.

• Bulletin of the Korea Photovoltaic Society
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• v.6 no.1
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• pp.35-44
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• 2020

In line with the goal of achieving a low carbon future, the Philippines made an aspirational target which aims to increase the total installed capacity coming from renewable energy (RE) to at least 20,000 MW by 2040. The country's RE sector has progressively advanced over the years following the enactment of its comprehensive RE Law in 2008. Among other RE technologies, solar achieved the highest installation growth from 2008 to 2018. The paper seeks to assess whether the Philippines' RE target by 2040 is achievable in terms of the current status and future outlook for RE. Major roadblocks that hamper RE development are identified and discussed, including some recommendations for policy-making and energy planning.