• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.76-79
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• 2003

Recently, many attempts have been made to develop high strength and high modulus fibers from conventional polymers such as poly(vinyl alcohol) (PVA)[1-4] and polyethylene (PE). PVA has potentiality to yield high strength and high modulus fiber, since they have high theoretically attainable moduli because of their planar zig-zag structure. As PVA has a melting temperature as high as 230$^{\circ}C$ in contrast to PE with a low melting temperature such as 130$^{\circ}C$, it seems possible that high strength and high modulus fibers comparable to Aramid can be fabricated from PVA. (omitted)

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.182-188
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• 2006

This study propose cutting body portion-high strength bolts to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connection. And, we report that loading test results of steel beam-to-column connection using high deformation capacity-high strength bolts in accordance with SAC2000 loading program. As a result, the initial stiffness and the maximum strength of the connection using high deformation capacity-high strength bolts, are approximately the same in comparison with those of the end-plate connection using the existing high strength bolts. But the deformation capacity of the connection is more than twice as much as those.

• Progress in Superconductivity and Cryogenics
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• v.24 no.1
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• pp.1-7
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• 2022

So far, large-scale scientific devices such as nuclear fusion tokamaks and high energy circular accelerators were constructed using high-current conductors made of metallic superconducting wires. Recently, as REBCO superconducting wires usable in high magnetic fields have been developed by several companies, researchesto apply high current cable type REBCO conductors to next-generation large superconducting magnets were also started. High critical currents of several kA or more in high magnetic fields have been successfully demonstrated on test samples of REBCO cable conductors by several research groups. In this review article, the main features and properties of the representative high current REBCO conductors such as CORC(Conductor On Round Core), TSTC(Twisted Stacked-Tape Cable) and RACC(Roebel-Assembled Coated Conductor), which are currently being developed at abroad are briefly introduced. Research activities of high-current density REBCO MHOS(Multi HTS layers on One Substrate) conductor at KERI, whose structure is different from other cable type REBCO conductors are also shortly introduced.

• Korean Journal of Health Education and Promotion
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• v.10 no.1
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• pp.87-97
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• 1993

The purpose of this study is to give practical information about eyesight care-preventing refractive error and actual conditions of wearing glasses(or contact lenses) to help school health education, For this study, 1,216 freshmen were sampled from liberal and vocational high schools in Seoul and the survey was successfully accomplished. Following are the major findings results of this study: 1. The percentage of the freshmen wearing glasses in girls high school were 57.5 percent in liberal high school and 41.7 percent in vocational high school. 2. The percentage of both the students and parents wearing glasses were 49.9 percent in liberal high school and 33.8 percent in vocational high school. 3. From the survey, the majority of the students began to wear glasses during their middle school years. The percentages were 46.6 percent in liberal high school and 62.1 percent in vocational high school. 4. The percentage of the students who got their glasses prescribed from an ophthalmic clinic were 60.6 percent in liberal high school, 31.5 percent in vocational high school and the rest got their glasses from the optician.. 5. The percentage of the students wearing glasses who didn't have optometry check-up for 6 months were 57.2 percent in liberal high school and 38.4 percent in vocational high school. The percentage of the students not wearing glasses in the same situation were 61.9 percent in liberal high school and 41.5 percent in vocational high school. 6. The percentage of the students who believe that the health education in school is necessary for the prevention of amblyopia were 79.2 percent of strdents attending in liberal high school, 82.9 percent in vocational high school, 81.5 percent of students wearing glasses and 80.8 percent of students not wearing glasses.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.3
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• pp.770-782
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• 2015

The purpose of this study was to inquiry of perception of Meister high school and specialized vocational high school' teachers and students on problem solving ability domain of test for enhanced employ ability & upgraded proficiency. Research subjects and region were teachers and sophomore students of each one of Meister high schools and specialized vocational high schools in Gyeongsangnamdo and Gwangju region. The questionnaire was composed of 4 research areas. Research areas were demographic characteristics, questions aspects, operational and enforcement aspects and side support for the development of test for enhanced employ ability & upgraded proficiency. Teachers questionnaire were composed of 15 items and students questionnaire were composed of 8 items. Further the research were interviewed research and targets were teachers and students of Meister high school and specialized vocational high school. The samples(N=719) of teachers and students were drawn from 2 high schools and collected data were analyzed with SPSS. The results were as follows. Perception of Meister high school students regarded more items of test for enhanced employ ability & upgraded proficiency as appropriate than specialized vocational high school students. Perception of Meister high school students regarded more CBT system as appropriate than specialized vocational high school students. Perception of specialized vocational high school teachers regarded more items of level of difficulty, degree of completion, validity than Meister high school teachers.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.168-168
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• 2022

According to the 5th Climate Change Report, global average temperature in 2081~2100 will increase 1.8℃ based on RCP 4.5 and 3.7℃ based on RCP 8.5 from the current climate value (IPCC Working Group I AR5). As temperature is expected to increase due to global warming and the intensity and frequency of rainfall are expected to increase, damage to crops is expected, and countermeasures must be taken. This study intends to evaluate rice growth in terms of nitrogen utilization efficiency according to future climate change conditions. In this experiment, Oryza sativa cv. Shindongjin were planted at the SPAR facility of the NICS in Wanju-gun, Jeollabuk-do on June 10, and were planted and grown according to the standard cultivation method. Cultivation conditions are high temperature, high CO₂ (current temperature+4.7℃·CO₂ 800ppm), high temperature (current temperature+4.7℃·CO₂ 400ppm), current climate (current tempreture·CO₂ 400 ppm). Nitrogen was varied as 0, 9, 18 kg/10a. The N content and C/N ratio of all rice leaves, stems, and seeds increased at high temperature, and the N content and C/N ratio decreased under high temperature and high CO₂ conditions com pared to high temperature. Compared to the current climate, NUE increases by about 8% under high temperature and high CO₂ conditions and by about 2% under high temperature conditions. This seems to be because the increase in temperature and CO₂ induced the increase in biomass. ANUE related to yield decreased by about 70% compared to the current climate under high temperature conditions, and decreased by about 45% at high temperature and high CO₂, showing a tendency to decrease compared to high temperature. This appears to be due to reduced fertility and poor ripening due to high temperature stress. However, as the nitrogen increased, the number of ears and the number of grains increased, slightly offsetting the production reduction factor.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.106-112
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• 2003

High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining and an estimate about machining accuracy of high-speed machining.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.460-465
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• 2003

High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages fur the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining and an estimate about machining accuracy of high-speed machining.

• Fire Science and Engineering
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• v.3 no.2
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• pp.3-10
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• 1989

The results on high strength concrete by heating high are as follows: 1. High strength concrete appeared an estimated 5.5% higher than ordinary concrete in the central temperature of specimens by heating. 2. High strength concrete is higher than ordinary concrete in the decreased width of the ratio on the residual compressive strength by heating high. According to heating temperature and time, the inferred formula of compressive strength on high strength concrete showed: Fc=-0.53Te -2.4Ti +748.4

• Journal of Power Electronics
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• v.5 no.4
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• pp.257-263
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• 2005

This paper describes the development and testing results of a high density High Voltage Power Supply (HVPS) that drives microwave Traveling Wave Tubes (TWTs) of phased array transmitters for airborne EW systems. The HVPS is designed to consist of a number of modules connected in series. Among them, especially, the high-density pulse transformer module including the resonant circuit is newly designed to make the HVPS much more reliable. In addition, this paper describes the development of high voltage solid-state modulation using fast switching devices (FETs) and also represents the test results of a modulator module.