• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.421-426
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• 2005

In general, structural integrity of rolling stock structures should last more than 25 years. During the lifetime corrosive degradation occurs. For structural design and diagnosis, quantitative relationship between corrosive degradation and variation of mechanical properties such as tensile strength and fatigue strength is needed. In this study, first of all we established the atmospheric corrosion test procedure. At regular intervals using specimens of SM490A and SS400 on the atmospheric corrosion test bed, we carried out tensile and fatigue tests. The fatigue strength decreases as the atmospheric corrosion period increases. And we studied the effect of post-weld heat treatment on the tensile and fatigue behaviour.

• 수산해양교육연구
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• 제28권1호
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• pp.118-126
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• 2016

The purpose of this study is for old-aged women to analysis variation of Body composition and BMD so that help to keep healthy life by doing low-intensity workout. the subjects for this study consist of 20 persons being aged over 65 women, doing not regular workout, living in P metropolitan, and do workout for 12 weeks by catergorizing into 2 groups in half depending upon whether doing workout or not. Two-way Repeated Measures ANOVA of SPSS 18.0 was used for data processing. the statistical significant is set as p<.05. In result, there's none of dramatical difference in radius, ulna's BMD. there is dramatical difference in (%)Fat, WHR in workout group but none difference in LBM.

• 음성과학
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• 제15권2호
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• pp.101-110
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• 2008

The purpose of this study was to investigate the speech intelligibility of voice disordered patients when we consider the severity and utterance level as variables. Based on the severity level, 12 patients were divided into three groups, G1, G2, and G3 group, respectively. Words, phrases and sentences produced by the speakers were judged by four listeners with normal hearing, and we compared the intelligibility scores of the three groups. As a result, the speech intelligibility was decreased as the severity level was increased, and the difference was statistically significant. However, the mean difference among words, phrases and sentences was not significant, and the variation of intelligibility according to the utterance level was not under the regular rules.

• 대한수학회보
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• 제55권5호
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• pp.1463-1481
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• 2018

Let $X=\{X_t\}_{t{\geq}0}$ be a $L{\acute{e}}vy$ process in ${\mathbb{R}}^d$ and ${\Omega}$ be an open subset of ${\mathbb{R}}^d$ with finite Lebesgue measure. The quantity $H_{\Omega}(t)={\int_{\Omega}}{\mathbb{P}}^x(X_t{\in}{\Omega})$ dx is called the heat content. In this article we consider its generalized version $H^{\mu}_g(t)={\int_{\mathbb{R}^d}}{\mathbb{E}^xg(X_t){\mu}(dx)$, where g is a bounded function and ${\mu}$ a finite Borel measure. We study its asymptotic behaviour at zero for various classes of $L{\acute{e}}vy$ processes.

• 설비공학논문집
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• 제11권2호
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• pp.176-184
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• 1999

Numerical and experimental studies were performed to examine the characteristics of heat and mass transfer processes for a Micro Heat Pipe(MHP) with a triangular cross-section. Solutions on mass flow rate, pressure variation, and radius of meniscus were obtained using the mathematical model developed by Faghri and Khrustalev. To obtain an increase in capillary limitation, a triangular tube with curved walls was designed and fabricated. The measurement by microscope showed that the radius at corners of the tube was ranging between 0.03-0.05mm. Performance test for MHPs using the triangular tube with curved walls proved a substantial increasement in heat transport limitation, with 4.5W and 2.0W in case of using water and ethanol as a working fluid, respectively. In the previous study by Faghri a limitation of 0.5W was reported for a water MHP with a regular triangular tube.

• 한국동물학회지
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• 제9권1호
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• pp.16-20
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• 1966

The frequency of sex chromatin in neutrophil leukocyte of 14 female and 4 male normal, adult rabbits was examined and compared to those of single total X-ray irradiation. 1. The average frequency of of drumstck was 9 % in female and 0.1% in male, and that of sessile nodule was 3.35% in female and 0.9% in male , in normal condition rabbit . These results fairly determined sex ratio by sex chromatin in neutrophil leukocyte. 2. The drumstick frequency reduces to half after X-irradiaton but did not show any regular tendency or variation in morphologicla form, indicating the stability of chromatin to X-irradiation. 4. The chromatin satellite was found with a reasonable frequency in the some kinds of irradiated cells, polymorphonuclear neutrophil (above 7 lobes 0 and megakarycyte.

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.45-50
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• 2014

Ambiguity in the root morphology of the mandibular second molars is quite common. The most common root canal configuration is 2 roots and 3 canals, nonetheless other possibilities may still exist. The presence of accessory roots is an interesting example of anatomic root variation. While the presence of radix entomolaris or radix paramolaris is regarded as a typical clinical finding of a three-rooted mandibular second permanent molar, the occurrence of an additional mesial root is rather uncommon and represents a possibility of deviation from the regular norms. This case report describes successful endodontic management of a three-rooted mandibular second molar presenting with an unusual accessory mesial root, which was identified with the aid of multiangled radiographs and cone-beam computed tomography imaging. This article also discusses the prevalence, etiology, morphological variations, clinical approach to diagnosis, and significance of supernumerary roots in contemporary clinical dentistry.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 추계학술대회 논문집
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• pp.73-76
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• 2002

A one-dimensional fluid model has been established for Raman amplification of a short laser pulse in a plasma by a counter-propagating pump. The laser pulse is amplified with a large gain and also may be compressed by nonlinear three-wave Interactions. The spatiotemporal evolutions of the seed and the pump pulses were visualized for linear and nonlinear regimes, and the transition from regular to chaotic behavior of subsidiary pulses was investigated with variation of pump intensity.

• Ocean Systems Engineering
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• 제2권4호
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• pp.239-255
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• 2012

Analysis of ship parametric roll has generally been restricted to simple analytical models and sophisticated time domain simulations. Simple analytical models do not capture all the critical dynamics while time-domain simulations are often time consuming to implement. The model presented in this paper captures the essential dynamics of the system without over simplification. This work incorporates various important aspects of the system and assesses the significance of including or ignoring these aspects. Special consideration is given to the fact that a hull form asymmetric about the design waterline would not lead to a perfectly harmonic variation in metacentric height. Many of the previous works on parametric roll make the assumption of linearized and harmonic behaviour of the time-varying restoring arm or metacentric height. This assumption enables modelling the roll motion as a Mathieu equation. This paper provides a critical assessment of this assumption and suggests modelling the roll motion as a Hills equation. Also the effects of non-linear damping are included to evaluate its effect on the bounded parametric roll amplitude in a simplified manner.

• 원예과학기술지
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• 제34권5호
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• pp.677-691
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• 2016

To assess South Korean commercial tomato cultivars, regular and cherry tomato cultivars were grown in the greenhouse and evaluated for color attributes, titratable acidity, pH, total soluble solids, carotenoids (lycopene and ${\beta}$-carotene), total phenols, flavonoids, vitamin C, and antioxidant activity. Significant differences (p < 0.05 using Duncan's multiple range test (DMRT)) were observed in the levels of most phytochemicals, quality parameters, and antioxidant activity among the twenty South Korean tomato cultivars tested. Lycopene and ${\beta}$-carotene contents varied significantly (p < 0.05 using DMRT), from $0.95mg{\cdot}100g^{-1}$ to $5.12mg{\cdot}100g^{-1}$ and $0.65mg{\cdot}100g^{-1}$ to $3.56mg{\cdot}100g^{-1}$ of fresh weight, respectively. ${\beta}$-carotene contents exhibited the highest genetic variation (59.2%), followed by naringenin (52.8%) and other phytochemicals. Most of the cherry tomato cultivars had statistically higher levels (p < 0.05 using DMRT) of carotenoids, phenols, flavonoids, vitamin C, and antioxidant activity compared to the regular tomato varieties, suggesting their higher nutritional value. Lycopene content was highest in the cultivars YoYo, Jicored, Titi-Chal, TY-Endorphin, and Rubyking. Cultivars Rubyking, TY-Endorphin, and Titi-Chal also showed relatively higher antioxidant activities in three assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric ion reducing antioxidant power (FRAP) assays. All the antioxidants, except luteolin, were positively correlated with antioxidant activities; the highest correlation was observed between total phenol and antioxidant activities, followed by the correlation between rutin and vitamin C. Cultivars identified to have superior nutritional status would be useful in tomato breeding programs to further improve quality and health benefits of tomatoes for the fresh and processed markets.