• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.3
• /
• pp.280-285
• /
• 2023

A breakdown voltage and breakdown electric field of the transformer insulating oil of liquid dielectric were studied in uniform electric field and non-uniform electric field and the transformer insulating oil was observed by the process reached breakdown. Insulation performance evaluation of the liquid dielectric was evaluated at the electrode spacing of 2.5 mm under the conditions of domestic and international standards (KS C IEC 60156), so a comparative review was conducted at the electrode spacing of 2.5 mm. When the electrode spacing is 2.5 mm, the average breakdown voltage is 38.5 kV for sphere-sphere electrodes, 26.6 kV for plate-plate electrodes, 22.9 kV for needle-needle electrodes, and 24.3 kV for sphere-needle electrodes. 23.7 kV for the sphere-plate electrode, and 20.7 kV for the needle-plate electrode. From these results, it can be seen that the average value of the breakdown voltage at the electrode spacing of 2.5 mm, in ascending order, is sphere-sphere, plate-plate, sphere-needle, sphere-plate, needle-needle and needle-plate. It was found that the breakdown voltage of the unequal field was lower than that of the equal field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.4
• /
• pp.403-407
• /
• 2023

In this paper, in order to investigate the efficiency of solar power generation system operation, we have studied operation cases such as generation amount, utilization rate, and generation time, and the following conclusions were obtained. The amount of power generation in 2017 was 1,311.48 MWh, and the amount of power generation in 2018 was 1,226.03 MWh. In 2021, 1,184.28 MWh was generated, and 90.30% compared to 2017, and the amount of power generation decreased by 1.94% every year. The deterioration of photovoltaic modules could be seen as one cause of the decrease in power generation. 1,977.74 MWh was generated in the spring, and 1,621.77 MWh was generated in the summer. In addition, 1,478.87 MWh was generated in the fall, and 1,110.55 MWh was generated in the winter, showing a lot of power generation in the order of spring, summer, fall, and winter. From 2017 to 2022, the seasonal utilization rate, daily power generation time, and daily power generation were investigated, and it could be seen that the spring utilization rate varies from 19.29% to 16.99%. It could be seen that the daily generation time in winter decreased from 2.67 hours to 2.13 hours, and in spring it generated longer than spring from 4.63 hours to 4.08 hours. In addition, the daily power generation in winter also decreased from 2.67 MWh to 2.13 MWh, and in spring it decreased from 4.63 MWh to 4.08 MWh, but it could be seen that it is more than in winter.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.4
• /
• pp.408-412
• /
• 2023

In this paper, in order to analyze high electrical insulation and cooling performance using mineral oil, the liquid insulating oil was changed in electrode shape and distance between electrodes to compare and analyze electrical characteristics according to equal electric field, quasi-equivalent electric field, and unequal electric field. As a result, the breakdown voltages were 36,875 V and 36,875 V in the form of sphere-sphere and plate-plate electrodes with equal electric fields. The breakdown voltage was 31,475 V in the sphere-plate electrode type, which is a quasi-equilibrium field, and the breakdown voltage was 28,592 V, 27,050 V, and 22,750 V in the needle-needle, sphere-needle, and needle-plate electrode types, which are unequal fields. Through this, it is possible to know the difference in breakdown voltage according to the type of electric field. The more equal the field, the higher the breakdown voltage, and the more unequal field, the lower the breakdown voltage. The difference in insulation breakdown voltage could be seen depending on the type of electric field, the insulation breakdown voltage was higher for the more equal electric field, and the insulation breakdown voltage was lower for the more unequal electric field. Also, it was confirmed that the closer the distance between the electrodes, the higher the insulation breakdown voltage, the higher the insulation breakdown current, and the insulation breakdown voltage and the insulation breakdown current were proportional.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.4
• /
• pp.369-375
• /
• 2023

In this paper, we compared and analyzed the power load patterns of dormitory buildings and office buildings to use them as basic data (demand analysis and capacity design) for the design and operation of microgrids for multi-use facilities, and the following conclusions were got. During the daytime on regular weekdays, the power consumption load pattern of office buildings was relatively large at 264.0~332.3 kWh, and during the evening hours, the power consumption load pattern of dormitory buildings was relatively large at 233.0~258.3 kWh. In the case of vacation, during the daytime on weekdays, the power consumption load pattern of office buildings was relatively large at 279.1~407.4 kWh, and in the evening, the power consumption load pattern of dormitory buildings was relatively high at 280.1~394.1 kWh. During the daytime on regular weekends, the power consumption of dormitory-type buildings was relatively high at 133.5~201.6 kWh, and it was found that the power consumption of dormitory-type buildings appeared relatively high at 187.5~252.1 kWh. During a vacation in the daytime on weekends, the power consumption of dormitory-type buildings was found to be 186.5 kWh~ and 218.6 kWh. The increase in power consumption during a vacation (December-February) compared to normal (April-June) was thought to be due to an increase in electricity demand, and the reason for the higher power consumption in dormitory buildings during the vacation was due to reduced working hours in office buildings.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.12a
• /
• pp.68-68
• /
• 2020

최근 기후온난화 및 다문화 가정 증가에 따라 아열대작물 재배 및 수요가 증가하고 있다. 차요테(Sechium edule (Jacq.) Sw.)는 멕시코 남부와 중앙아메리카가 원산인 아열대 채소로 박과에 속하는 다년생 덩굴식물이다. 차요테는 아삭아삭한 식감에 가벼운 단맛을 가지고 있으며, 그 맛이 오이, 무와 비슷하다. 라틴아메리카에서는 튀김, 샐러드, 수플레로 필리핀에서는 수프과 볶음의 재료로 활용한다. 국내에서는 식감이 좋아 열매를 장아찌 용으로 이용하거나 어린순과 잎을 무침용으로 이용하기도 한다. 차요테는 매우 낮은 칼로리를 지녔으며 포화지방이나 콜레스테롤을 함유하지 않아 다이어트 식품으로 알맞은 채소이다. 또한 비타민 C와 E, K가 풍부하여 피로 해소, 면역력 개선, 피부 미용, 감기 예방, 골다공증이나 암 예방, 동맥경화 방지는 물론 신경전달물질인 세로토닌과 멜라토닌 형성에도 도움을 준다. 그밖에 칼륨, 마그네슘, 망간, 구리, 아연 등의 미네랄이 함유되어 있어 세포의 성장과 분열, 면역체계의 활성화, 심장과 근육 기능 유지 등에 기본적인 도움을 준다. 따라서, 본 연구는 차요테의 가공식품 소재화를 위해 부위별 유용성분 함량 분석을 통한 차요테 이용 확대를 위해 수행하였다. 차요테는 잎에서 열매와 어린순에 비해 지방, 단백질, 탄수화물, 식이섬유 등이 높게 나타났으며, 비타민 C, E 및 칼슘과 철분도 높은 함량을 나타내었다. 또한 장에 존재하여 다당류를 단당류로 분해하는 효소인 Alpha-Glucosidase의 활성을 억제하여 탄수화물 흡수를 지연시켜 체내 혈당을 낮추는 효과를 나타내는 AGI 활성은 열매 부위에 가장 높게 나타났다.

• Journal of Korean Ophthalmic Optics Society
• /
• v.9 no.2
• /
• pp.233-239
• /
• 2004

This study investigated the status of soft contact lens wear in college students. The results were as follows: 1. The most prevalent age of initial contact lens wear was 19 years or 20 years, with an age distribution in females from as early as 10 years to 20 years. 2. For almost all subjects, the test clinic for the contact lens wear assessment and purchase of the contact lenses was an optical shop. 3. The main advantage for most male subjects was use for sports, whereas most female subjects used contact lenses for cosmetic reasons. 4. The most common side-effects experienced due to contact lens wear were red eye, foreign body sensation, and eye pain. 5. The most frequently reported eye disease caused by contact lens wear was conjunctivitis, with only few subjects experiencing keratitis. 6. Following treatment for the side effects of contact lens wear, most subjects hoped to re-use the previous contact lenses, some subjects wanted to change to new contact lenses, and others subjects refused further contact lens wear.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.18 no.6
• /
• pp.242-247
• /
• 2008

The glass and glass-ceramics containing EAF dust $30{\sim}70\;wt%$ were fabricated and the dependance of physical properties upon crystal phases and microstructure formed was studied. The crystallization behavior of glass and glass-ceramics containing various contents of EAF dust composing of mainly $Fe_2O_3$ and ZnO was analyzed by crystal identification and microstructure observation. The glass specimen with EAF dust 30 wt% showed a typical amorphous pattern in XRD results and the specimen with above 30 wt% EAF dust had some un-dissolved crystals which was originated from EAF dust. The all glass-ceramics had franklinite, willemite and augite crystal phases. The density of glass-ceramics was higher than that of same composition glass, and it increased with EAF dust contents. In addition, the thermal and mechanical properties of glass-ceramics were always higher than those of glasses. In other words, the thermal expansion coefficient of glass increased with EAF dust contents while it decreased for the glass-ceramics. The vickers hardness for the glass and glass-ceramics increased with EAF dust content, the glass-ceramics always being higher those of glass of same composition.

• Journal of the Korean Applied Science and Technology
• /
• v.33 no.2
• /
• pp.311-323
• /
• 2016

By studying bioactivity in the aspect of skin care via curcumin, the main component of turmeric, and isoflavones, the soybean extract, this research tried to prove the possibilities as cosmetic ingredients. This research identified the curcumin and soybean extract's anti-inflammatory and toxic effects on skin cells through cell experiment, and using HPLC, the moisture, oiliness, and changes in erythema were measured when the soybean extract was applied to the skin. The result showed that curcumin had the least toxin on RAW 264.7 cell and the anti-inflammatory effect was identified. There were statistically significant changes on the moisture, oiliness and erythema when cosmetics containing curcumin and soybean extract were used. Therefore, it showed the possibilities of the utilization of curcumin and soybean extract to be used as cosmetics for acne skin.

• Fashion & Textile Research Journal
• /
• v.9 no.1
• /
• pp.89-95
• /
• 2007

The purposes of this study were to investigate the names and locations of beauty-related high schools, and to examine the cources and subjects of beauty-related high schools according to types of high schools. Data were obtained from 8 beauty-related high schools, which consisted of 2 schools for each beauty-related high schools types and permitted the investigation of their curriculum. The findings of this study were as follows: First, These were about 30 beauty-related high schools that were mostly industrial high schools, located in Busan and Kyungsang Province, and almost used "Beauty" or "Aesthetics" as the name of department. Second, the rates of common and professional courses of business high schools and industrial high schools were similar to those suggested from the Ministry of Education and Human Resources. But for specialized high schools and integrated high schools, the rate of these courses were not in accord with those of the Ministry of Education and Human Resources. Third, The credit hour of special study in beauty-related high schools largest in hair care, followed by skin care and makeup courses. But nail and foot care were established only 2-3 beauty-related high schools. Fourth, The number of subjects of special study were largest in specialty high school. Industrial high schools offered the least number of subjects of special study. Fifth, as a result of making a comparative analysis of their subjects of special study, eight high schools offered hair care, skin care, public health and makeup courses, which had the same or similar titles. The independence titles were established nail care and foot care. The others titles were established actual training, food and nutrition, digital image processing, accounts theory, coordinatin.

• The Korean Journal of Community Living Science
• /
• v.25 no.2
• /
• pp.193-205
• /
• 2014

This study investigates soldiers' and civilians' interest in and behaviors toward cosmetics and skin beauty. Responses to a self-administered questionnaire were collected from 150 soldiers and 156 civilians residing in Chung-chung Province, Korea. The mean age of the respondents was $21.9{\pm}1.8$. More than 90% used skin toner and lotion products, and more than 50% used sunblocks and foam cleansers. Soldiers were more likely to use essence (p<.001) and after-shave (p<.01) products than civilians. In addition, soldiers were more likely to use carrier cosmetics than their counterparts (p<.001~p<.05). Soldiers were more likely to be concerned about their skin (p<.01) and unsatisfactory environments for skin care (p<.001), more likely to engage in skin care behaviors (p<.01), and less likely to have skin knowledge than civilians (p<.001). There was a negative relationship between skin knowledge and skin care behaviors (p<.01). The level of interest in appearance was correlated with that in skin (p<.001). The number of skin related concerns was positively correlated with unsatisfactory environments for skin care (p<.001). Concerns over appearance (p<.001), skin (p<.001), and unsatisfactory environments for skin care (p<.05) were positively correlated with skin care behaviors. The results suggest the necessity of providing a diverse and differentiated range of cosmetics to meet the needs of soldiers and men, particularly the former, according to the differences in their environments.