• Proceedings of the KWS Conference
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• 2002.10a
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• pp.570-576
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• 2002

Application of the aged Inconel 718 in hydrogen environment is seriously restraint by its high hydrogen embrittlement (HE) sensitivity. m previous researches, we have suggested the possibility and applicability of the laser surface annealing (LSA) process in improving the HE resistance of this alloy. Sequentially, a study on the effects of the precipitates in the Inconel 718 on its HE sensitivity was conducted in this research. Firstly, flat bar specimens were heat-treated to obtain various kinds of precipitation microstructures concerning the ${\gamma}$" phase and the 6 phase. Hydrogen was charged into the specimen by a cathodic charging process. The loss in reduction of area (RA) caused by hydrogen charging was used to assess the HE sensitivity. The HE sensitivity of the alloy was lowered with decreasing the volume fraction of ${\gamma}$". Moreover, it was possible to increase the HE resistance of the aged alloy by dissolving the $\delta$ phase, keeping the strength at the same level as that of the common aged alloy. Thus, we concluded that both the $\delta$ phase and the ${\gamma}$" phase affected the HE sensitivity of Inconel 718. Next, two kinds of notch tensile specimens were fabricated, one kind having $\delta$ phase and the other having no $\delta$ phase. All these specimens were aged via the same aging heat treatment process. The LSA process annealed a thin layer of the notch bottom of each specimen. One specimen of each kind was charged with hydrogen by the cathodic hydrogen charging process. Loss in the notch tensile strength (NTS) caused by hydrogen was used to evaluate the HE sensitivity. It was found that while the HE sensitivity of conventionally aged Inconel 718 was decreased by the LSA process, the HE sensitivity of the $\delta$-free aged Inconel 718 could further be decreased. Therefore, for applications in hydrogen environments, it is possible to fabricate alloys with both good HE resistance and high strength by controlling the precipitation conditions, and to improve HE resistance further via applying the LSA process.

• The Journal of the Petrological Society of Korea
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• v.19 no.4
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• pp.255-267
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• 2010

The primary utilization of recently improved (U-Th)/He thermochronometry is to reveal the low-T thermal histories of shallow crustal sections or transient episodes (such as wildfires or meteorite impacts) because of the high sensitivity of He diffusion to temperature in host minerals. In this contribution, we present reviews and perspectives regarding how this method can be used to characterize the ejection-related shock metamorphism of Martian meteorites. The temperature conditions of shock metamorphism can be constrained through shock recovery experiments, paleomagnetism, and $^{40}Ar/^{39}Ar$ and (U-Th)/He dating. The most reliable constraints can be deduced when these independent approaches are combined. However, the thermal history of the ALH84001 Martian meteorite has been under serious debate because the different methods have yielded contrasting results. Recent work has shown how single-grain (U-Th)/He and $^{40}Ar/^{39}Ar$ dating, two noble-gas based thermochronometries with different T sensitivities, can be used to resolve this issue, providing a good example for future research on other meteorites.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.719-730
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• 2014

The hot water extract from Artemisia capillaris fermented with Hericium erinaceum mycelium (AC-HE) were assessed for the protection against oxidative modification of biological macromolecules and cell death. Antioxidant activity of AC-HE evaluated using 2,2-diphenyl-1-picrylhydrazyl radical, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical and peroxyl radical scavenging assays. AC-HE showed 61.73% DPPH radical scavenging activity at $500{\mu}g/mL$, 97.39% ABTS radical scavenging activity at $250{\mu}g/mL$, and 44.18% peroxyl radical scavenging activity at $100{\mu}g/mL$. AC-HE were shown to significantly inhibited DNA strand breakage induced by peroxyl radical. AC-HE also prevented peroxyl radical-mediated human serum albumin modification. AC-HE effectively inhibited $H_2O_2$ induced cell death and significantly increased of the 11.47% cell survival at $100{\mu}g/mL$. AC-HE also decreased intracellular reactive oxygen species (ROS) levels in $H_2O_2$-treated cells. The results suggested that AC-HE can contribute to antioxidant and protected cells from oxidative stress-induced cell injury.

• The Journal of Korean Philosophical History
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• no.27
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• pp.145-166
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• 2009

This paper analyzes the views of Gyeongjae O Chiik on Classical Studies. O is the second son of Noju O Heesang (1763-1833). The characteristics of his views are as follows. First, unlike his father, Gyeongjae is more interested in Chinese Textual Criticism than in Hsing-li hsüeh. Therefore, he provides textual interpretation in detail with erudition in his Manrok and Munjip on the formation and problems for such classics as The Four Classics, The Classic of Poetry, The Book of Changes, The Rites of Zhou, The Book of Rites, and The Spring and Autumn Annals. Second, his openness. He didn't canonize The Book of Changes. Also, he thought that the analysis of Jeongja in his Annotation on the Book of Changes and Zhuxi's Original Interpretations, the absolute authority of the time, were not the only interpretation possible. He argued that other interpretation is possible depending on perspectives and it is desirable. We can see that Gyeongjae had transcended the world view of Zhuxi Studies. Third. he put the emphasis on the theories during the Han dynasty. He showed the inclination toward the Yuheung theories rather than Zhuxi theories in regard of the discussion of names in The Analects of Confucius. Fourth, unlike other Confucius scholars in Chosun, he showed interests in Gongyangjeon and Gokryangjeon. He compiled Gonggokmunseon with beautiful writings from both works. Fifth, he was interested in the dynamics of constant numbers. He grasped that what is important in the Book of Changes is not right principles but constant numbers and points. Thus he compiled Sangjeomyuhoe. Besides, he was also interested in the Rites of Zhou.

• Human Ecology Research
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• v.61 no.4
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• pp.673-686
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• 2023

The purpose of this study was to identify home economics (HE) teachers' concerns about and perceptions of HE education using the latest technologies in the era of the 4th Industrial Revolution and to reveal whether they differ according to teachers' general background variables. The questionnaire survey method to measure HE teachers' concerns and perceptions of HE education using the latest technologies in the era of the 4th Industrial Revolution was conducted online using the Google Questionnaire from which 150 responses were received. The main results were as follows. Firstly, HE teachers scored an average of 3.46 out of 5 for the latest technology. Among these interests in the latest technology, interest in "augmented reality and virtual reality technologies" scored the highest at an average of 3.80, while interest in "neural network machine learning" (2.78) was low. HE teacher's concerns about HE education using the latest technologies in the era of the 4th Industrial Revolution were high, with an average score of 4.40. Among these concerns for the latest technology, "concern about the results of HE education using the latest technology" scored the highest at 4.53. HE teachers' anxiety about the latest teaching technology in the era of the 4th Industrial Revolution was moderate, averaging 3.05. The highest form of anxiety was "anxiety about the impact on the job" (4.03) and the lowest was fear of "the disappearance of the teacher's job" (2.50). HE teachers' innovation resistance to the latest teaching technology was low at 2.18. Expectations of the latest technology in HE classes in the era of the 4th Industrial Revolution averaged 3.85, slightly higher than the middle of 3.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.70-70
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• 2003

액체 로켓 엔진에 있어 극저온 추진제인 액체 산소를 사용하는 경우에는 He을 가압제로 사용하는 것이 가장 바람직하지만, 기체인 헬륨은 발사 대기시, 선가압시, 비행중에 액체산소에 서서히 녹게 된다. 일정량 이상의 He이 용해되어 있는 LOX가 엔진에 공급되는 경우에는 터보펌프의 이상 작동 또는 연소 불안정을 야기하게 되므로, 추진기관이 작동하는 동안에 용해되어 있던 He이 액체 산소에서 분해되어 가스로 발생되는지 여부를 판단하고, 이는 엔진의 연소 시험을 통해서 검증되어야 한다. 본 연구에서는 가상의 작동 상태에 대해 최대로 용해될 수 있는 러e의 양을 계산하고, 현재 사용되는 발사체의 경우와 비교를 하여 추진시스템 운용 조건을 적절히 조절하는 방안을 제시하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 1997.07a
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• pp.177-180
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• 1997

현재 플라즈마 디스플레이에 이용되는 He-Ne-Xe 이원가스의 단점을 상호보완하기 위하여 He-Ne-Xe 혼합가스의 방전특성 실험을 수행하였다. Xe(5%)에서 He:Ne의 혼합비는 3:2일 때 최적의 휘도와 구동전압, 색순도를 갖는 것으로 나타났으며, Xe의 혼합비의 대해서는 Xe의 혼합비가 증가할수록 휘도와 색순도가 향상되었으며 구동전압은 높아졌다.

• Journal of the Korean housing association
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• v.10 no.4
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• pp.53-62
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• 1999

Choonwon, Lee Kwang-Soo was a literary man and activist for educational movement in modem age of Korea. This research was to review his arguments about improvement of house living. The major results of the research were as follows. First, he asked Korean people to establish solid identity of living. Second, he placed great emphasis on building hygiene facilities and bathroom. Third, he argued that the space within a household need to be divided in accordance with function. Finally he suggested Korean people to make home environment beautiful and convenient.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 1999.02a
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• pp.161-164
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• 1999

$^{3}$He melting curve thermometer is made, tested, and compared with Greywall scale. The experimental results show that we can identify the temperature within a few percentage. To improve the accuracy of our thermometer we need temperature fixed points like $^{3}$He superfluid phase transition temperature.

• Natural Product Sciences
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• v.9 no.4
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• pp.210-212
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• 2003

In the present study Momordica dioica fruit pulp was successively extracted with hexane and methanol. To the concentrated methanolic extract ethyl acetate was added and ethyl acetate soluble portion was separated. Both hexane extract (HE) and ethyl acetate soluble portion (EASP) of methanolic extract was vacuum dried to yield the respective HE and EASP. HE and EASP were evaluated for its analgesic and anti-inflammatory activities in a dose of 50 and 100 mg/kg in mice and rats. Both HE and EASP significant exhibited analgesic and anti-inflammatory activities when compare to standard drug.