• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.88-89
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• 2002

The aims of this study is to realize the structural design for development of a medium scale E-glass/epoxy composite wind turbine blade for a 750KW class horizontal axis wind turbine system. In this study, the various load cases specified by the IEC61400-1 international specification and GL Regulations for the wind energy conversion system were considered, and a specific composite structure configuration which can effectively endure various loads such as aerodynamic and centrifugal loads, loads due to accumulation of ice, hygro-thermal and mechanical loads was proposed. In order to evaluate the structure, the structural analysis for the composite wind turbine blade were peformed using tile finite element method(FEM). In the structural design, the acceptable blade structural configuration was determined through the parametric studies, and the most dominant design parameters were confirmed. In the stress analysis using the FEM, it was confirmed that the blade structure was safe and stable in any various load cases Moreover the safety of the blade root joint with insert bolts, newly devised in this study, was checked against the design fond and the fatigue.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.116.1-116.1
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• 2011

L1448-MM, known as a class 0 YSO with a prominent outflow, was observed with the Photodetector Array Camera and Spectrometer (PACS) aboard Herschel Space Observatory by the key program, DIGIT (Dust, Ice, Gas in Time, PI: Neal Evans). The PACS covers various molecular and atomic line transitions such as CO, OH, $H_2O$, [OI], and [CII] at wavelengths from 55 to 210 ${\mu}m$. The line emission of $H_2O$, [OI], mid-J CO, and the OH fundamental transition distributes along the outflow direction although high-J CO and other OH emission peaks at the central spatial pixel. According to our excitation analysis, the CO gas has two temperature components: 300 K and 750 K, which are attributed to PDR and shock, respectively. However, the $H_2O$ gas with the rotation temperature ($T_{rot}$) of 200 K seems only affected by shock. Interestingly, the relative strength of OH transitions suggests the IR pumping process in L1448-MM. We also mapped L1448-MM in CO J=2-1 with the SRAO 6m telescope to compare with the FIR line transition maps.

• Journal of the Society of Naval Architects of Korea
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• v.48 no.2
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• pp.171-177
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• 2011

Tensile tests were conducted at low temperatures for the steel materials which are used for outer shell of the vessels making transit through the polar regions. The selected steel materials were GL-DH32, GL-DH36 and GL-EH36. In comparison with the results at room temperature, the yield stress increases approximately by 10 to 13 percent at $-30^{\circ}C$ and by 13 to 19 percent at $-50^{\circ}C$ while the tensile strength increases about by 9 percent at $-30^{\circ}C$ and 11 to 14 percent at $-50^{\circ}C$. To obtain true stress-true strain, i.e. correct plastic hardening characteristics, Bridgman's(1952) necking correction formula was introduced taking triaxial state of stresses after onset of diffuse necking into consideration. Photographs of fractured surfaces were taken by using Scanning Electron Microscope immedately after tensile tests completed and one for GL-EH36 has been presented in this paper.

• Journal of Ocean Engineering and Technology
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• v.37 no.5
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• pp.215-224
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• 2023

While melting glaciers due to global warming have facilitated the development of polar routes, Arctic vessels require reliable anti-icing methods to prevent hull icing. Currently, the existing anti-icing method, i.e., the heating coil method, has disadvantages, such as disconnection and power inefficiency. Therefore, a carbon nanotube-based surface heating element method was developed to address these limitations. In this study, the numerical analysis of the surface heating element method was performed using ANSYS. The numerical analysis included conjugate heat transfer and computational fluid dynamics to consider the conduction solids and the effects of wind speed and temperature in cold environments. The numerical analysis method of the surface heating element method was validated by comparing the experimental results of the heating coil method with the numerical analysis results (under the -30 ℃ conditions). The surface heating element method demonstrated significantly higher efficiency, ranging from 56.65-80.17%, depending on the conditions compared to the heating coil method. Moreover, even under extreme environmental conditions (-45 ℃), the surface heating element method satisfied anti-icing requirements. The surface heating element method is more efficient and economical than the heating coil method. However, proper heat flux calculation for environmental conditions is required to prevent excessive design.

• Journal of Science Education
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• v.38 no.1
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• pp.41-56
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• 2014

This study has developed STEAM educational program designed to cultivate topophilia using Jeonbuk educational resources and applied the program to a science camp. Topophilia is a sense of attachment and nostalgia towards one's birth place and specific objects, which can create positive affection and act as motivations for learning to the students. We developed a 32-hour STEAM program which consisted of 8 experiential activities and 2 travel programs including Gochujang, Hanok Village, a reverse ice spikes in Mai Mountain, and art works by Choi Book. In particular, we emphasized the fun of class, voluntary learning, and process of attaching significance by providing aesthetic and emotional experience of synesthesia. As a result of application, the students' level of confidence(Likert scale level 4, 2.5 points) in science and the level of interests(3.3 points) have improved. The pleasant experience of voluntary learning and active participation in class provided meaningful memories through value recognition and significance ascription. 93.3% of the students participated said they would recommend the Topophilia science camp to their peers. The level of satisfaction overall was 3.8 points(Likert scale level 5) and the program received positive evaluations that the class was fun and interesting(4.1 points).

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.411-424
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• 2019

The purpose of this study is to explore the feasible policy directions for sports welfare that can not only improve the standard of living through health but also ensure a happy and enjoyable life for the people of Gangwon Province. For this purpose, I have conducted studies such as the analysis on the sports class voucher project being implemented by the South Korean government and the case analysis in sports welfare, and present policy directions as follows. First of all, it is about upgrading the sports class voucher project. And as its implementation plans, I suggest ① increased publicity, ② the earmarking of the province's own budget for the sports class voucher project, ③ the establishment of a system for cooperation for work implementation between the related organizations and their staff in charge with a view to activating the sports class voucher project, and ④ the upgraded services for the sports class voucher project and the upgraded access to the life cycle-based universal welfare. Second, it is about using public sports facilities and developing various programs. I suggest the active utilization of the public sports facilities that enable people to learn the skills for such sports disciplines as baseball, badminton, ice sports, and golf and the development and distribution of distinctive educational programs for dance for media entertainment shows for female youths, climbing, cheer leading, fencing, surfing and horseback riding. Third, it is about nurturing the human resources and networking. For this, I suggest the creation of 'Sports Welfare Specialist Training Program' and the training of the college students majoring in sports science with the aim of creating a number of jobs. Fourth, it is about refurbishing the system and establishing the support system. I suggest the dismantling of the partitions in the welfare policy related to sports activities and the formation of (tentatively named) 'Gangwon Province Sports Welfare Implementation Committee', and the creation of (tentatively named) 'Sports Welfare Project Support Team' in Health, Welfare & Women's Affairs Bureau or Culture, Tourism and Sports Bureau in the short term and then its long-term expansion into (tentatively named) 'Gangwon Province Sports Welfare Support Center' in responding to the needs that reflect the provincial demographics, with a view to establishing a single lineup for the administrative support system. Furthermore, as budget and manpower are needed to realize customized sports welfare that suits the characteristics of the province and in which all the provincial residents can collect benefits, I suggest that the province provide the legal basis through creating 'Ordinance Promoting Sports Welfare in Gangwon Province' and pushing forward with (tentatively named) 'Gangwon Province Sports Welfare Competition' as what revises the sports class voucher project for the purpose of broadening the basis for sports welfare promotion.

• Journal of the Korean Society of Costume
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• v.66 no.3
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• pp.107-120
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• 2016

This study examines functions in traditional Korean special costumes in accordance with the climatic factors of the Korean peninsula. The study focused on clothes worn by commoners during the Joseon dynasty. Climate change has been a major global issue in recent times, and it has been a hot topic in social, cultural, scientific, economic, and industrial communities. Studies have been conducted regarding the rapidly changing climate, and finding ways to cope with unusual temperatures. This thesis studies the development of special costumes in preparation for unusual climates, and requirements of the costume in accordance with the climatic factors, as well as the direction of its development. Its biggest significance lies in collecting and organizing the research data on special costume studies, and on costumes of the commoners, which have been fairly insufficient up to this point. After the Little Ice Age, the Joseon Dynasty period faced poor external environment due to unusual temperatures. The results of studying the costumes of the commoners are as follows: The climate of the Korean peninsula displayed different characteristics depending on the season, so the form, material, and appearance of the seasonal clothing items showed clear differences, and the difference in the crops cultivated according to the climate led to difference in material and material preference shown in the costumes. This meant that costumes differed based on region. In addition, difference in social hierarchy, regulations on costume according to class, and farming oriented social background during the period of Joseon dynasty slowed the development of costumes of commoners, but appears to have had a positive effect on the development of special costumes. We anticipate more succeeding studies on costumes of the commoners and special costumes in the future. We hope more costumes that can wisely respond to the approaching changes in temperature in the Korean peninsula can be designed via modernization of traditional Korean special costumes.

• Journal of Nutrition and Health
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• v.9 no.4
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• pp.28-35
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• 1976

To know changes of the food preferences and the practice of pica during pregnancy, ninety two women in the latter half of pregnancy were interviewed in April, 1976 at ten medical centers in Seoul. They were average 27.1 years old, and mostly middle class. 83.7% of the total subjects felt the changes of food preferences due to pregnancy within the first trimester. 60.9% had vomiting as well as losing their appetite and 17.3% vomited three or more times daily which might induce difficulties of water and electrolytes balance in body. The preferences about foods, the taste of foods, and various dishes cooked during morning sickness were changed significantly and showed in lower scores of likes and higher scores of dislikes than those before pregnancy. Particularly, cooked rice and kimchi indicated the increase of more than 50% in dislikes. The preferences after the morning sickness were turned back to those before pregnancy. Desire for water through foods like soft drinks, juice, ice cream, and gamju and salty foods seemed to be spontaneous during pregnancy. A majority of the subjects had three meals and no snack had included more snacks instead of meals during losing appetite and thereafter, had more frequent meals and snacks. Superstitions about chicken, squid, and cuttlefish for pregnant women were prevalent. 11.9% tabooed chicken because of harm for fetus. On the contrary, intended higher inclusions of milk, meat and dried small sardines would be helpful to satisfy the increased recommended allowances of calcium and protein for them. The practice of pica was found in 5.4% and rice was the only real item mentioned. Pica such as amylophagia or geophagia often reported in the U.S. was not answered in this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.9
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• pp.600-605
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• 2014

The interest in development on luminaires which are available up to $-52^{\circ}C$ is surging as demands in vessels navigating a north pole route increase. A conventional incandescent lamp used in vessels is operated stably at $-52^{\circ}C$, but many countries including Korea have eliminated the use of incandescent lamps gradually because of its low luminous efficacy. In this paper, therefore, to develop the LED luminaires with high-efficiency, long lifetime that enables to substitute for incandescent lamp, it has studied about cryogenic characteristics of LED packages, bulbs, driving circuit and power supply. This experiments were carried out according to standards IEC 60945-8.4.1. Temperature range is from $-60^{\circ}C$ to $25^{\circ}C$, and the light output depending on ambient temperature. It showed that, based on $25^{\circ}C$, light output of a CFL decreased by 80% of CFL at $-20^{\circ}C$ while each increased 12% of LED bulbs and 16~19% of LED packages at $-60^{\circ}C$.

• Ocean and Polar Research
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• v.36 no.4
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• pp.319-326
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• 2014

Mineral dust in the polar snow plays an important role both in the climate system of the Earth and in global biogeochemical cycles. Analysis of the concentration and the particle size distribution of mineral dust has been carried out in the snow from the Antarctic surface snow and the Greenland snowpit. Among the various particle size determination techniques, a Multisizer 3 Coulter Counter in a class 100 clean bench counted all particles between 1.1 and $30.0{\mu}m$ with a $50{\mu}m$ aperture tube. The aperture tube size, the concentration of electrolytes and the accuracy of the particle size distribution were determined in this study. The number concentrations from the Antarctic surface snow were 81,843 particles $mL^{-1}$, but those from the Greenland snowpit were 10,666 particles $mL^{-1}$. In the volume distribution, the distributions of mineral dust in both the Antarctic surface snow and the Greenland snowpit showed lognormal distribution in the size interval 1.1 to $6.0{\mu}m$ with the mode, 3.562 and $3.836{\mu}m$, respectively. The analysis technique using a coulter counter for mineral dust could be used for reconstructing paleoclimates from polar ice cores.