• The Korean Journal of Mycology
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• v.31 no.3
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• pp.148-154
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• 2003

Extracts from 52 samples of mushrooms were prepared by using water, ethanol and methanol, and then yields and angiotensin I-converting enzyme(ACE) inhibitory activity were investigated. Sample mushrooms contained crude proteins of $7.1{\sim}56.5%$, curde lipids of $0.2{\sim}4.4%$ and carbohydrates of $30.3{\sim}86.6%$. Among 52 samples, the water extract from fruiting body of Pholiota spp. ASI 24027 showed the highest extraction yield of 68%. Water extract of Pholiota spp. ASI 24012 fruiting body had potential ACE inhibitory activity of 66%. The optimal extraction condition of the ACE inhibitor from the fruiting bodyies of Pholiota spp. ASI 24012 was In water at $30^{\circ}C$ for 1 hr and ACE inhibitory activity was 67.6% on the condition with 0.2 mg of $IC_{50}$.

• Korean Journal of Medicinal Crop Science
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• v.15 no.6
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• pp.391-397
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• 2007

To develop new high valuable Gugija (Lycium chinensis), biofunctionalities of Gugija standard species and its hybrids were investigated and compared with each water extracts and methanol extracts from Lycii Fructus, Lycii Folium and buds and Lycii Cortex Radicis. Among various biofunctionalities of Gugija standard species, antioxidant activity was showed the highest in methanol extracts from buds of Cheongwoon species (93%) and antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity was 84.1% in the water extracts from Lycii Cortex Radicis of Cheongyang NO.7. Futhermore, methanol extracts from Lycii Cortex Radicis of Myungan A-2 hybrid showed 93.1% of antioxidant activity and 96.9% of ACE inhibitory activity was also showed in the methanol extracts from Lycii Fructus of DO148-72(A11) hybrid. However, fibrinolytic activity and anticholesteromia HMG-CoA reductase inhibitory activity were weak or not detected in almost of Gugija standard species and its hybrids. Therefore, we finally selected Cheongwoon Gugija standard species (buds) and Myungan A-2 hybrid (Lycii Cortex Radicis) as good antioxidant sources and also DO148-72 (A11) hybrid (Lycii Fructus) as excellent antihypertensive ACE inhibitior sources for manufacturing functional food product.

• Journal of the Korean Institute of Gas
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• v.4 no.3 s.11
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• pp.1-8
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• 2000

It is required that gas accidents should be managed carefully as the consumption of fuel gas increases and high pressure gas process becomes more complex, which may cause a catastrophic accident. Factors to cause accidents were investigated through a systematic analysis of gas accidents between 1995 and 1998, which could be applied to prepare countermeasures to reduce gas accidents. As a result, it was suggested that the effective countermeasures to gas accidents should be kept applied, while new countermeasures were suggested in the field of increasing or not-decreasing number of accident. Totally 2,027 of accidents were reported during this term, and were found to decrease by about $12\%$ every year from 1996. The number of fuel gas such as LPG and city gas accident took up $96\%$, and most of accidents occurred at end-user's facility such as residential house and restaurant business. According to the kind of gas and facility, trend of accident by cause varies, while dominant causes are defective installation, appliance failure, or user's carelessness. Intentional accidents by fuel gas was excluded in this study because of its occurring mechanism and will be analyzed further elsewhere, although it took up $15\%$ and increased by $38\%$ every year.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.346-346
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• 2007

압전세라믹 재료는 현재 압전 변압기, actuator, transducer, sensor, speaker 등에 광범위하게 이용이 되고 있다. 이 중에서 압전세라믹 소결체를 이용한 스피커의 제조는 가공이 까다롭고, 대형의 크기로 제작 시 소자가 깨지는 등의 많은 제약을 받고 있으며, 저음 특성이 떨어져 응용 범위가 한정되어 있다. 따라서 최근에는 이러한 단점을 극복하기 위하여 세라믹/고분자 복합체를 이용한 필름 스피커를 제작하고자 시도하고 있다. 이러한 세라믹/고분자 0-3형 압전 복합체를 이용할 경우, 제품의 경량화를 실현할 수 있고, 크기나 환경의 영향을 거의 받지 않으므로, 고기능성 스피커로의 응용에 적합할 것으로 보인다. 따라서 본 연구에서는 PZT계의 세라믹와 PVDF, PVDF-TrFE, Polyester, acrylic resin 등의 여러 고분자 물질과의 복합체를 제조하여 압전특성을 평가하였다. 본 실험은 먼저 $(Pb_{1-a-b}Ba_aCd_b)(Zr_xTi_{1-x})_{1-c-d}(Ni_{1/3}Nb_{2/3})_c(Zn_{1/3}Nb_{2/3})_dO_3$ (이하 PZT라 표기)의 최적화 조성을 선택하여, $1050^{\circ}C$에서 소결된 분말을 48시간 ball milling방법 로 약 $1{\mu}m$ 크기로 분쇄하였다. 고분자 물질들은 알맞은 용제들을 선택하여 녹였다. 그 다음 소결된 PZT분말과 고분자를 50:50, 60:40, 65:35, 70:30등의 무게 분율로 혼합하고, 분산제, 소포제 등을 첨가하여 3단 roll mill을 이용하여 충분히 분산시켜 페이스트 (Paste)를 제조하였다. 제조된 페이스트를 ITO가 코팅된 PET필름 위에 스크린 프린팅 법을 사용하여 인쇄하여 $120^{\circ}C$에서 5분간 건조하였다. 코팅된 복합체의 두께는 약 $80{\mu}m$ 정도로 측정되었다. Ag 페이스트를 이용한 상부 전극 형성에도 스크린 프린팅 법을 적용하였다. 이를 $120^{\circ}C$에서 4 kV/mm의 DC 전계로 분극 공정을 수행한 후 전기적 특성을 평가하였다. 유전특성을 조사하기 위해서 LCR meter (EDC-1620)를 사용하였고, 시편의 결정구조는 XRD (Rigaku; D/MAX-2500H)을 통해 분석하였으며, 전자현미경(SEM)을 이용하여 미세구조를 분석하였다. 압전 전하상수$(d_{33})$ 값은 APC 8000 모델을 이용하여 측정하였다. PZT의 혼합비가 증가할수록 비유전율 및 압전 전하 상수 등의 전기적 특성이 증가되었다. 또 여러 고분자 물질 중에서 PVDF-TrFE 수지가 가장 우수한 특성을 보였다. 이는 PVDF-TrFE 수지가 압전성을 나타내기 때문인 것으로 판단되었다.

• Korean Journal of Food Science and Technology
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• v.48 no.5
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• pp.525-529
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• 2016

Twenty-nine pepper products commercially available in the market were collected and investigate for contamination levels. Pepper products purchased from traditional markets had a degree of contamination of $10^6-10^7CFU/g$ aerobic bacteria, $10^4-10^5CFU/g$ Bacillus sp., and less than $10^2CFU/g$ yeast and molds. Organic pepper showed a degree of contamination of $10^4$ aerobic bacteria, $10^2-10^3$ Bacillus sp., and less than $10^1$ yeast and molds. Intense pulsed light (IPL) treatment of 10 min (1,000 V, 5 pps and 4 cm sample-to-lamp distance) showed a bacterial death rate of 1.45-1.55 log for whole peppers, and of 0.8-0.85 log for black and white pepper powder. The sterilization rate using IPL was higher than that using other non-thermal sterilization methods, such as ozone treatment or low-pressure discharge plasma sterilization, indicating that the IPL sterilization method may find potential application in the industry. However, further studies may need to be conducted to enhance the effect of sterilization.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.59-68
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• 2021

As artificial intelligence(AI) technologies, which have made rapid growth recently, began to be applied to the marine environment such as ships, there have been active researches on the application of CNN-based models specialized for digital videos. In E-Navigation service, which is combined with various technologies to detect floating objects of clash risk to reduce human errors and prevent fires inside ships, real-time processing is of huge importance. More functions added, however, mean a need for high-performance processes, which raises prices and poses a cost burden on shipowners. This study thus set out to propose a method capable of processing information at a high rate while maintaining the accuracy by applying Quantization techniques of a deep learning model. First, videos were pre-processed fit for the detection of floating matters in the sea to ensure the efficient transmission of video data to the deep learning entry. Secondly, the quantization technique, one of lightweight techniques for a deep learning model, was applied to reduce the usage rate of memory and increase the processing speed. Finally, the proposed deep learning model to which video pre-processing and quantization were applied was applied to various embedded boards to measure its accuracy and processing speed and test its performance. The proposed method was able to reduce the usage of memory capacity four times and improve the processing speed about four to five times while maintaining the old accuracy of recognition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.593-601
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• 2021

The axial fan is an element of a blower used for ventilation in various industrial fields. Many studies on aerodynamic performance have been conducted to assess axial fans using fluid dynamics. The subject was a large axial fan size, 1800 mm in diameter with 100 horsepower. The blower's axial fan consisted of blades, hubs, hub caps, and bosses are important components. The blade design has a great influence on the aerodynamic performance. 3D point data is extracted using an aerodynamic performance prediction program, and a 3D modeling shape is generated. The blades and hubs, which are important components, can be easily modified if processed by cutting owing to the environment in which blades and hubs are manufactured through die casting or gravity casting. In this study, the structural safety of components and the analysis results of weak areas at the rated operating speed of the axial fan were verified using the maximum stress and safety factor. The tip clearance reflected in the design was the rotation of the blade. To check whether there is interference with other components, the displacement result was derived to verify the structural safety of the axial fan.

• Journal of Navigation and Port Research
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• v.44 no.6
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• pp.550-556
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• 2020

Over the past years, the role of ports in the global network of supply chains has becoming increasingly important, not merely as a physical location for loading and unloading goods, but also as an essential center of economic activity where additional value is added to cargo. Due to the overall growing importance of ports, each country has chosen to adopt hub growth as a primary economic strategy. Northeast Asia in particular, due to its high population density, experiences intense competition between its ports. Busan's port, as a result, has used the establishment of Distripark in order to attract high and stable trade volume, and compete more effectively with other ports in the region. This study estimates the unit cost of the logistic process for the all principal cargos handled at Busan New Port, with the findings revealing that unit cost increases gradually starting with chemical products, LME bulk goods, automobile parts, LME containers, general cargoes, and LME inland transportation goods coming in last. Future research will look more closely at all all categories of cargo handled in the Distrpark of Busan New Port, thereby enabling us to better understand the value created by the port, and how to best implement effective trade volume-attraction strategy.

• Journal of Platform Technology
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• v.8 no.3
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• pp.10-21
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• 2020

Partial discharge occurs a lot in high-voltage power equipment such as switchgear, transformers, and switch gears. Partial discharge shortens the life of the insulator and causes insulation breakdown, resulting in large-scale damage such as a power outage. There are several types of partial discharge that occur inside the product and the surface. In this paper, we design a predictive model that can predict the pattern and probability of occurrence of partial discharge. In order to analyze the designed model, learning data for each type of partial discharge was collected through the UHF sensor by using a simulator that generates partial discharge. The predictive model designed in this paper was designed based on CNN during deep learning, and the model was verified through learning. To learn about the designed model, 5000 training data were created, and the form of training data was used as input data for the model by pre-processing the 3D raw data input from the UHF sensor as 2D data. As a result of the experiment, it was found that the accuracy of the model designed through learning has an accuracy of 0.9972. It was found that the accuracy of the proposed model was higher in the case of learning by making the data into a two-dimensional image and learning it in the form of a grayscale image.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.310-316
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• 2021

Conventional satellites are generally large satellites that are multi-functional and have high performance. However, small satellites have been gradually drawing attention since the recent development of lightweight and integrated electric, electronic, and optical technologies. As the size and weight of a satellite decrease, the barrier to satellite development is becoming lower due to the cost of manufacture and cheaper launch. However, solar panels are essential for the power supply of satellites but have limitations in miniaturization and weight reduction because they require a large surface area to be efficiently exposed to sunlight. Space solar cells must be manufactured in consideration of various space environments such as spacecraft and environments with solar thermal temperatures. It is necessary to study structural materials for lightweight and high-efficiency solar cells by applying an unfolding mechanism that optimizes the surface-to-volume ratio. Currently, most products are developed and operated as solar cell panels for space applications with a triple-junction structure of InGaP/GaAs/Ge materials for high efficiency. Furthermore, multi-layered junctions have been studied for ultra-high-efficiency solar cells. Flexible thin-film solar cells and organic-inorganic hybrid solar cells are advantageous for material weight reduction and are attracting attention as next-generation solar cells for small satellites.