• 한국압력기기공학회 논문집
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• 제16권1호
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• pp.65-73
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• 2020

Integrity evaluations on a platen superheater were conducted as per ASME Section VIII Division 2(hereafter 'ASME VIII(2)') which was originally used for design with implicit consideration of creep effects. A platen superheater subjected to severe loading conditions of high pressure and high temperature at creep regime in a supercritical thermal plant in Korea was chosen for present study. Additional evaluations were conducted as per nuclear-grade high-temperature design rule of RCC-MRx that takes creep effects into account explicitly. Comparisons of the two results from ASME VIII(2) and RCC-MRx were conducted to quantify the conservatism of ASME VIII(2). From present analyses, it was shown that the design evaluation results exceeded allowable limits of RCC-MRx for the plant design conditions although limits of ASME VIII(2) were satisfied regardless of operation time, which means that design as per ASME VIII(2) might be potentially non-conservative in case of operation in creep range. A high-temperature design evaluation program as per RCC-MRx, called 'HITEP_RCC-MRx' has been used and it was shown that pressure boundary components can be designed reliably with the program especially for the loading conditions of long-term creep conditions.

• Animal Systematics, Evolution and Diversity
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• 제26권1호
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• pp.15-19
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• 2010

The Russian ratsnake, Elaphe schrenckii, is found in Russia, China, and Korea, and is considered to be an endangered species by the Ministry of Environment in South Korea. Due to habitat loss and use in oriental medicine, their population has been severely decimated. In South Korea, two subspecies of E. schrenckii has been defined according to body color: E. s. schrenckii (blackish) and E. s. anomala (yellow-brownish). Molecular genetic studies on Elaphe schrenckii are very scarce and the taxonomy of Elaphe schrenckii subspecies is uncertain. From the present study, we attempted to identify the genetic differences of these two subspecies using species-specific microsatellites developed from the genomic library of E. schrenckii. Nine polymorphic loci were tested on 19 individuals from E. s. schrenckii (n=10) and E. s. anomala (n=9) in South Korea. The mean number of alleles was 3.78 in E. s. schrenckii and 4.11 in E. s. anomala. The average expected heterozygosity was 0.542 and 0.511 in E. s. schrenckii and E. s. anomala, respectively. We found a lack of genetic structure between two subspecies ($F_{ST}=0.016$) and no genetic discrimination between two subspecies was found. Based on the present findings by microsatellites, two subspecies can be considered as one species, E. schrenckii. However, further investigations on taxonomical status using mitochondrial and nuclear DNA sequences need to be performed and morphological & ecological data should be revised. The genetic markers should benefit future studies of the endangered species of other Elaphe species for the study of genetic diversity and potential conservation management.

• 대한기계학회논문집
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• 제12권3호
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• pp.520-527
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• 1988

본 연구에서는 액체용 이젝터의 성능을 결정하는 여러가지 제약인자중 특히 레이놀즈수 변화에 따른 구동노즐의 면적비 및 목부길이가 액체용 이제터성능에 미치 는 영향을 체계적인 실험을 통하여 연구함으로써 기 개발된 CAD용 전산프로그램의 타 당성을 보다 세밀히 검토하고 이에 보완을 가하는데 연구의 목적이 있다.

• 한국가정과학회지
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• 제7권3호
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• pp.83-106
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• 2004

As the lifespan has been expanded, the marital relationship later in life is getting more important. This study is to find out what the demand for the education of marital couples to improve this relationship. The results can be used as basic data to develop educational programs for elder couples. The results of this study are as follows. 1. Couple role according to socio-demographic variables can be divided into traditional and modern roles. And these variables are shown to be significant in couple role. 2. Need for the education of married couples according to socio-demographic variables. In case of spouses having shorter marriage period, religion, and a nuclear family, and doing social activities, the necessity of education is recognized highly. Those who have a spouse with good health and social activities have experienced a chance to attend the educational program. It is thought that health and social activities have much to do with active living attitude. In case of old age, it can be thought that they don't feel the necessity because they have lived a decent life for a long time. It is just that it comes from the fixed ideas of elder couples who had to spend only a short time with their spouses. That is what elder couples have to overcome. They tend to think that the relationship between the family is more important than that of spouses, and they put family relationship before the quality of their own lives. 3. Influence of the need for the education of married couples according to their role. As their role are becoming modern and their mutual trust, affinity, and cohesion are getting more important, the education of married couples and the experiences of communication and participation in the educational program are thought to be more necessary.

• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.194-200
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• 2020

Perylene bisimide derivatives are developed for red organic phosphor because of their advantages, such as excellent luminous efficiency and high thermal stability. Despite these advantages, they have poor solubility characteristics in organic solvents and short emission wavelength as red organic phosphor for hybrid light-emitting diodes (LEDs). In this study, we prepared terrylene bisimide using a coupling reaction and swallow-tail imide group, which has excellent solubility. The structures and properties of swallow-tail terrylene bisimide (9C) were analyzed using ¹H-nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared (FT-IR), UV/Vis spectroscopy, and thermal gravimetric analysis (TGA). The maximum absorption wavelength of (9C) in the UV/Vis spectrum was 647 nm, and the maximum emission wavelength was 676 nm. In the TGA, (9C) demonstrated good thermal stability with less than 5 wt% weight loss up to 415℃. In the solubility test, (9C) has a good solubility of more than 5 wt% in chloroform and dichloromethane. When the compounds (9C) were mixed with PMMA (polymethly methacrylate), the films showed peaks at 680 nm in the PL spectra. The results verify the suitability of (9C) as a red organic phosphor for hybrid LEDs.

• 한국압력기기공학회 논문집
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• 제8권3호
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• pp.13-22
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• 2012

According to recent research on leak-rate estimates to assess rupture probabilities of nuclear piping which contains a circumferential surface/through-wall cracks due to PWSCC, i.e., xLPR (Extremely Low Probability of Rupture) program, it has been revealed that the use of crack shape with an idealized circumferential through-wall crack during actual crack growth can lead to overestimate of the leak-rate. Thus, for accurate estimation of the leak-rate during crack growth, the more realistic crack shape that can simulate the crack shape transition from surface crack to through-wall crack should be used. In this context, in the present study, the elastic crack opening displacement of slanted circumferential through-wall crack in thick-walled cylinder was proposed based on 3-dimensional elastic finite element fracture mechanics analyses. To propose the elastic crack opening displacement of slanted circumferential through-wall crack in thick-walled cylinder, the geometric variables affecting crack opening displacement, i.e., thickness of cylinder, reference inner crack length and slant crack ratio were systematically varied. In terms of loading conditions, axial tension, global bending moment and internal pressure were considered. The present results can be applied to calculate the leak-rate considering more realistic crack shape transition from surface crack to idealized through-wall crack, and can be expected to enhance current leak-rate estimation scheme, for instance, in xLPR program etc.

• 대한방사선기술학회지:방사선기술과학
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• 제28권2호
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• pp.79-89
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• 2005

본 연구는 방사성동위원소 및 방사선 응용 분야에 있어서 우리나라가 연구개발 사업을 추진하는 데 도움이 될 수 있도록 국제원자력기구(IAEA) 프로그램의 현황을 검토하고 향후 전망을 제시하였다. 특히 국제기구를 통한 공동연구 프로그램 참여를 증진시킬 수 있도록 IAEA 프로그램 참여시 이점을 고찰하고 이의 필요성을 강조하였다. 또한 신규 참여 증진을 위한 방향을 제시하고 이의 효율적인 운영 방안을 제안하였다. 본 논문에서 제시된 전략과 구체적인 방안이 향후 국제공동연구 확대를 위한 정책 수립에 활용되고, 방사선기술 응용 연구를 수행하는 국내 산 학 연 연구기관의 국제공동연구 참여 증진에 기여할 수 있기를 기대한다.

• Journal of Microbiology and Biotechnology
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• 제32권1호
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• pp.15-26
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• 2022

Luteolin is a common dietary flavone possessing potent anti-inflammatory activities. However, when administrated in vivo, luteolin becomes methylated by catechol-O-methyltransferases (COMT) owing to the catechol ring in the chemical structure, which largely diminishes its anti-inflammatory effect. In this study, we made a modification on luteolin, named LUA, which was generated by the chemical reaction between luteolin and 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH). Without a catechol ring in the chemical structure, this new flavone could escape from the COMT-catalyzed methylation, thus affording the potential to exert its functions in the original form when administrated in the organism. Moreover, an LPS-stimulated RAW cell model was applied to detect the anti-inflammatory properties. LUA showed much more superior inhibitory effect on LPS-induced production of NO than diosmetin (a major methylated form of luteolin) and significantly suppressed upregulation of iNOS and COX-2 in macrophages. LUA treatment dramatically reduced LPS-stimulated reactive oxygen species (ROS) and mRNA levels of pro-inflammatory mediators such as IL-1β, IL-6, IL-8 and IFN-β. Furthermore, LUA significantly reduced the phosphorylation of JNK and p38 without affecting that of ERK. LUA also inhibited the activation of NF-κB through suppression of p65 phosphorylation and nuclear translocation.

• 한국추진공학회지
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• 제26권2호
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• pp.40-46
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• 2022

홀추력기는 이온을 가속하여 추력을 얻는 전기추력기의 일종으로, 높은 비추력을 보유하여 다양한 우주임무에 활용되고 있다. 특히, 최근 다양한 우주임무 내 100 kg 내외의 소형 및 초소형위성의 활용이 가파르게 증가하면서, 이를 위한 저전력 전기추력기 연구개발의 중요성 역시 크게 증가하고 있다. 본 연구에서는 양극전력 200 W 미만의 홀추력기 랩모델 두 기를 설계 및 제작하고, 운전변수에 따른 추력성능 혹은 방전특성을 분석하였다. 결과적으로, 양극전력 50-175 W에서 2.5-9.0 mN 수준의 추력과 600-1,150 s의 비추력, 15-28% 양극효율을 확보하였다.

• 한국콘텐츠학회논문지
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• 제22권5호
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• pp.553-564
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• 2022

이 연구의 목적은 <삼시세끼> 어촌편 1이 재현한 가족을 살펴보는 것으로, 이야기 전개구성과 등장인물의 관계 특성을 서사분석을 활용해 분석하였다. <삼시세끼>는 '기상-자유시간-아침-점심-저녁-휴식-취침'의 비교적 단순한 전개구성을 보였다. 각 등장인물에게는 주된 공간과 역할을 배치함으로써 '차줌마', '바깥양반', '호주니'의 캐릭터를 완성해갔다. 출연진이 모두 남성임에도 이들에게는 아내/주부/엄마, 남편/가장/아빠, 아들의 가족지위가 부여되었고, 매우 고정된 감정과 획일적 행동의 가족실천이 탄탄한 관계구조 속에서 반복되었다. 동시에 유자녀 가족, 양부모 가족, 이성애가족, 핵가족이라는 전형적 근대가족, 정상가족, 표준가족을 연출하였다. 즉 <삼시세끼>는 스위트 홈의 표상을 적극 차용해 정상가족 이데올로기를 강화시켰다.