• 한국조명전기설비학회지:조명전기설비
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• 제1권2호
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• pp.62-69
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• 1987

이 논문은 Phenolic 수지의 Tracking파괴의 CTI에 관한 고찰로써 전극재료의 일부가 누설재료에 의하여 침식되기 때문에 tracking파괴를 증진시키며 다음과 같은 영향을 받는다. $\circled1$절연재료에서는 C. T. I의 값이 350정도에서는 현재까지 규정하고 있는 백금전극보다도 황동전극이 더욱 근사한 값을 얻을 수 있었다. $\circled2$C. T. I의 값은 전해액의 저항율과는 무관하다. $\circled3$시요표면의 접촉각이 증가함에 따라 Corona 개시전압과 C. T. I의 값은 증가한다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.104-109
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• 2016

Purpose: The purpose of this study is to analyze fracture behavior and failure mechanism of porous titanium for dental implant fabricated by space holder process. Method: Three porous titanium specimens with a specific volume fraction of open pore were test by 3 point bending and compression stress condition, respectively. Fracture appearance was observed by scanning electron microscope and discussed in relation with oxygen content. Results: For compression-tested specimens, two specimen showed brittle failure, while the other one showed normal failure after deformation. High oxygen content was detected in the brittle-fractured specimen. Several micro-cracks initiated at the struts propagated down to the bottom of the specimen resulting in normal failure. Conclusion: Oxygen contamination during the fabrication process can leads brittle premature failure, and hence quality problem of the porous titanium for dental implant.

• 대한기계학회논문집A
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• 제25권4호
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• pp.654-661
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• 2001

In this study, fatigue growth behavior of the transverse crack, which was the most dangerous damage among the various types of rail defects, was investigated using the notched keyhole specimen under constant amplitude loadings. Fatigue limit of smooth specimen in rail steel at R=0 was 110MPa, and the fatigue crack initiation life in the region of the low stress amplitude (ie. long life) occupied the major portion of the total fatigue life. The fatigue strength under variable amplitude loading was converted to the equivalent fatigue strength based upon. Miners rule, which was estimated approximately 9% lower than that under constant amplitude loading. Also, in the low ΔK(sub)rms region ($\leq$21MPa√m), fatigue crack growth rate (da/dN) under constant amplitude loading was higher than that under variable amplitude loading, whereas the tendency was reversed in the high ΔK(sub)rms region. It is believed that this behavior is due to the transition of fracture appearance.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1752-1759
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• 2007

In the new Seoul-Busan high speed railroad construction specially city center passage roadbed establishment is recommended the staibility for the existing subway tunnel segments of Busan subway line No. 1 and No.2. regarding the appearance condition, a quality condition and the durability of the objective facility site exact inspection, and it evaluates the numerical analysis which uses MIDAS GTS it leads and there is the objective of the place where the stability of the objective facility and this tunnel it investigates. To immediacy of the on-the-spot inspection result whole facility it is a condition where the reinforcement which is simple not to be hindrance is necessary, 2nd Line case it is a condition which transfer is good but the general defect and the damage which occur from the tunnel of NATM type were confirmed part. While roadbed establishment constructing that the continuous maintenance is necessary, it is judged. The result of 1st, 2nd Line maximum sinkage, unequal sinkage and the lining stress of numerical analysis are within permission and the damage degree is appearing with the fact that the degree it will can disregard it is slight. But it enforces necessary Pre-grouting in order to minimize an actual tunnel face conduct and when the tunnel is excavated it is judged with the fact that necessary to minimize the outflow possibility.

• 한국식품영양학회지
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• 제25권3호
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• pp.579-589
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• 2012

This study was performed to investigate the eating habit, body image, and weight control behavior by BMI in Korean female high school students. Data on the 16,574 subjects was obtained from the sixth Korea Youth Risk Behavior Web-based Survey (2010). Only 52.2% of the subjects had regular breakfast. The rate of skipping breakfast was higher in the underweight group than in the obese group, but the rate of skipping dinner was on the contrary to this. Underweight students had a higher intake frequency of fruits, fast food, instant noodle, and snacks than the obese groups. 3.5% of underweight students considered themselves to be overweight or obese. 53.4% of obese students considered themselves to be overweight. The experience of weight control increased according to BMI, but underweight students considered weight control as an effort to be slimmer. Meal restriction was used more frequently to control weight. The perceived stress level was higher in obese student, especially due to appearance. Therefore, an appropriate, integrated and personalized high school nutrition program should be established for proper body image perception and to develop the self-esteem of female high school students.

• 대한족부족관절학회지
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• 제17권1호
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• pp.11-16
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• 2013

Freiberg's disease is a osteochondrosis of a metatarsal head that is recognized as primarily a disorder of the second metatarsal. It is seen more often in girls. Pain and limitation of motion of the affected joint is the predominant clincal feature. The radiographic appearance demonstrates from osteosclerosis in the early stage to osteolysis with collapse in the later stage. Conservative therapy may take the form of rest, a stiff shoe, and even a cast support to decrease the stress across the joint. Surgical intervention may also be of benefit. Surgery have been attempted either to modify the diseae process or to salvage the situation once the metatarsophalangeal joint develops degenerative changes. Metatarsophalangeal joint instability is common cause of forefoot pain that can develop in association with a traumatic episode and inflamatory tissue disorders as well as neighboring toe deformities. The second ray is by far the most frequently involved. The diagnosis can be made by clinical observation and physical examination including drawer test. Many surgical procedures have beem recommended when conservative treatment has failed. Procedures described range from soft tissue releases and tendon trasfer to the direct plantar plate repair combined with a Weil osteotomy.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.110-115
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• 1999

The surface gloss of an injection molded part is one of the most significant point for evaluating the quality of products appearance. The effects of process condition on the gloss of ABS(Acrylonitrile-Butadiene-Styrene) molded part were investigated in this work. The measurements of gloss and morphology on the surface of molded part were carried out with different melt temperature, mold temperature, mold surface roughness, injection pressure and holding pressure. Gloss had a maximum value with melt temperature in the range of 210 to 220 ${^\circ}C$ and with mold temperature 40 to 50${^\circ}C$ and with injection pressure 80~90 MPa, respectively. Melt temperature was shown to have the largest effect on gloss in our work. Gloss was not improved in the region of melt temperature 240${^\circ}C$ above and of mold temperature 60${^\circ}C$ above. It was concluded that the variation of gloss was mainly caused by rubber particles migration under shear stress not by their aggregation or necklace.

• 한국지반신소재학회논문집
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• 제2권1호
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• pp.3-13
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• 2003

최근 우수한 경제성과 수려한 외관 및 시공의 간편성 등에 의해 토목섬유를 보강재료로 이용한 보강토 구조물의 건설이 나날이 증가하고 있다. 이러한 토목섬유 보강토 구조물의 해석과 설계 시 가장 중요한 인자인 흙/토목섬유 마찰특성의 평가방법이 표준화되어 있지 않고, 기 제안된 해석 및 설계방법들에 큰 차이가 있어 실무설계자들에게 혼란을 주고 있다. 본 연구에서는 최근 보강재로 놀리 사용되고 있는 토목섬유와 국내 화강풍화토의 마찰특성을 인발시험을 통해 보다 합리적을 평가할 수 있는 방법을 제시하기 위해, 인발시험의 주요 영향인자들인 인발속도, 보강재의 종류, 토목섬유 시료의 폭, 수직하중 및 토목섬유의 수동저항 부재의 유 무 등을 고려하여 흙/보강재의 마찰정수를 도출하였다.

• Journal of Microbiology and Biotechnology
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• 제27권2호
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• pp.365-371
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• 2017

Hydrogen has potential for preventive and therapeutic applications as an antioxidant. However, micro- and macroparticles of hydrogen in water disappear easily over time. In order to eliminate reactive oxygen species (ROS) related with the aging process, we used functional water containing nanoparticle hydrogen. Nanoparticle hydrogen does not disappear easily and collapse under water after long periods of time. We used murine embryonic fibroblasts that were isolated from 12.5-day embryos of C57BL/6 mice. We investigated the ability of nanoparticle hydrogen in water to suppress hydroxyurea-induced ROS production, cytotoxicity, and the accumulation of ${\beta}-galactosidase$ (an indicator of aging), and promote cell proliferation. The accumulation of ${\beta}-galactosidase$ in the cytoplasm and the appearance of abnormal nuclei were inhibited by daily treatment of cells with hydrogen water. When the aging process was accelerated by hydroxyurea-induced oxidative stress, the effect of hydrogen water was even more remarkable. Thus, this study showed the antioxidant and anti-senescence effects of hydrogen water. Nanoparticle hydrogen water is potentially a potent anti-aging agent.

• 동아시아식생활학회지
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• 제22권6호
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• pp.720-733
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• 2012

This study was conducted to investigate the eating habits, self-perception of body image, and weight control behavior in Korean adolescents by gender. Data pertaining to 70,809 subjects(male 37,090, female 33,719) were obtained from the sixth Korea Youth Risk Behavior Web-based Survey(2010). The rate of skipping breakfast was 42.5% in male, and 45.8% in female students. The intake frequency of vegetable, milk, soda, fast food, and instant noddles was higher in male than female students. Moreover, 33% of male and 31.9% of female students considered themselves to be somewhat or very obese. Notably, 2.3% of underweight students considered themselves to be obese. Weight control measures were practiced in 44.6% of male, and 54.6% of female students. Meal restrictions were used more frequently to control weight by females, while exercise was used more by males. The perceived stress level was higher in female than male students, especially that due to appearance. Therefore, integrated and personalized high school nutrition programs according to gender should be implemented to establish proper body image perception and eating habits, as well as to develop selfesteem.