• Journal of Dental Rehabilitation and Applied Science
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• v.35 no.1
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• pp.20-26
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• 2019

Purpose: Recently TF-adaptive movement is developed in order to increase the durability of TF files. The purpose of this study was to assess the effects of adaptive movement on durability and performance of twisted files. Materials and Methods: Resin blocks simulating artificial J-shape canals were used for this study. In TFC group, TF-adaptive ML-1 (25/.08 size) files were used to prepare the canals under continuous rotation 500 rpm/4.0 Ncm. In TFA group, TF-adaptive ML-1 (25/.08 size) files were used to prepare the canals under adaptive movement. After preparing each artificial canal, TF files were observed under dental microscope for assessing existence of unwinding, distortion, and fracture. If unwinding of flute was observed, the number of artificial canals until unwinding of flute occurs was recorded. Required time until instruments reach working length and distance of unwinded portion of files from D0 were measured. All test results were conducted by Mann-Whitney U test at a 0.05 level of significance. Results: No Ni-Ti instrument's separation was observed. Number of resin blocks until file unwinding happens and working time was significantly high in TFA group compared to TF group. Distance of distortion from D0 didn't show significant difference between TFA, TF groups. Conclusion: The number of resin blocks prepared until unwinding happens and working time were significantly high in TFA group. The location of unwinding showed no significant difference between 2 groups. Adaptive movement increased the number of canals prepared until unwinding occurs and working time of twisted files.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.860-863
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• 2002

Recently, main nozzle and inner nozzle for EHV class gas circuit breakers were made by PTFE(Poly Tetra Fluoro Ethylen) for the basic material composite. But, nowadays strengthened PTFE was demanded because the supply of electric power increased. This paper shows the research results for nozzles according to the filler materials.

• Journal of the East Asian Society of Dietary Life
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• v.21 no.6
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• pp.871-876
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• 2011

In the present study, we investigated the compositions, antioxidant activities and anti-tumor effects of Artemisia princeps Pampanini (APD) as well as blanched leaves (CNBD) and dried leaves (CND) from Cirsium setidens Nakai on HepG2 cells. Water and ash contents were increased in CND. Protein and lipid contents were increased in CNBD. K, Ca, Mg, Fe and Cu contents of CND were higher than those of CNDB and APD. P contents was significantly decreased in CND. Yields of CND was reached high levels, but TPC, TFC, acacetin, apigenin, cynarin contents, and antioxidant activity were higher in APD. Viability of HepG2 liver cells was significantly decreased in APD. Therefore, extracts of APD are more effective preventing the liver cancer than extracts of CND and CNBD.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.55.3-55.3
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• 2015

We study the possibility of new approach for identifying instrumental noise artifacts and sources of gravitational wave (GW) data such as LIGO and CLIO using various correlation analyses.To improve the quality of data for the GW signal search, the instrumental noises should be reduced in an appropriate way. Furthermore, it is important to understand the correlation between auxiliary channels of the GW detector. In this study, we investigate the possible way of identifying glitch triggers by generating time-frequency-correlation (TFC) maps between the related channels and compare the result to the current conventional schemes.

• Natural Product Sciences
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• v.19 no.2
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• pp.186-191
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• 2013

Screenings of potential antioxidant activities of Crataegus pinnatifida BUNGE Major. fruits extracted 80% methanol were performed using four antioxidant assays. Significant differences were observed both in total phenolic contents (TPC) and total flavonoid contents (TFC), DPPH radical scavenging activity, nitric oxide scavenging activity, ABTS radical scavenging assay, and reducing power assay. The total polyphenol content and total flavonoid content in the extract were measured to be $224.4{\pm}0.52$ mg GAE/100 g and $12{\pm}0.25$ mg QE/100 g, respectively. When the tested concentration was $500{\mu}g/mL$, DPPH and ABTS radical-scavenging activities of methanolic extracts were 84.15% and 88.8%, respectively. The reducing power and nitric oxide scavenging activity were increased at the manner of dose-dependently. These results suggest that methanolic extracts of Crataegus pinnatifida Bge. fruits possess excellent radical scavenging activities and may serve as a potential source of natural antioxidant.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.198-201
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• 2008

매생이의 에탄올 추출물의 기능적 특성과 추출액의 플라보노이드와 페놀함량과의 상관성을 검토하고, 아질산염 분해능과 효소의 영향 등을 측정하였다. 매생이 에탄올 추출액의 클로로필 함량은 물추출보다 에탄올 추출의 경우가 높았으나, 플라보노이드 함량은 물추출액에서 약간 높게 나타났다. 추출액의 TPC함량은 TFC함량이 높을수록 높게 나타났으나 직접 비례하지는 않았다. 그리고 매생이에 함유된 아질산염 함량 측정결과와 아질산염 분해능 결파 비교로부터 에탄올 추출의 경우에는 아질산염 분해능이 시료자체의 아질산염 함량과 직접적인 영향이 없는 것으로 보였으며, 매생이 에탄올 추출액이 나타내는 아질산염 분해작용은 낮은 pH에서 높게 나타났으나, 매생이 자체에 존재하는 효소의 관여는 극히 미약하였다.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1833-1838
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• 2003

In the nuclear power plant, emergency core coolant system(ECCS) is furnished at reactor coolant system(RCS) in order to cool down high temperature water in case of emergency. However, in this coolant system, thermal stratification phenomenon can be occurred due to coolant leaking in the check valve. The thermal stratification produces excessive thermal stresses at the pipe wall so as to yield thermal fatigue crack(TFC) accident. In the present study, when the turbulence penetration occurs in the branch piping, the maximum temperature differences of fluid at the pipe cross-sections of the T-branch with thermal stratification are examine

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.32-38
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• 2008

Galgeuntang water extract exhibited a strong free radical scavenging activity and reducing power determination. However, a gradual increase in the free radical scavenging activity and reducing power determination was obtained with increasing concentrations. The highest radical scavenging activity was shown by the water extract from Galgeuntang (116.93 ${\mu}g$/mL) and the water extract from Cinnamonum cassia Presl. (95.01 ${\mu}g$/mL). These results of phenolic and flavonoid contents of the extracts indicated that the strong radical scavenging activity of the Cinnamonum cassia Presl. extract might be in part due to the phenolic compounds. The correlation coefficient between TPC and DPPH ($r^2$ = 0.9312), TFC and DPPH ($r^2$ = 0.9677), showed positive correlation among total phenolic/flavonoid contents and antioxidant activity. These results suggest that Galgeuntang has a potential antioxidant activity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.202-210
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• 2006

In the nuclear power plant, emergency core coolant system (ECCS) is furnished at reactor coolant system (RCS) in order to cool down high temperature water in case of emergency. However, in this coolant system, thermal stratification phenomenon can be occurred due to coolant leaking in the check valve. The thermal stratification produces excessive thormal stresses at the pipe wall so as to yield thermal fatigue crack (TFC) accident. In the present study, when the turbulence penetration occurs in the branch pipe, the maximum temperature differences of fluid at the pipe cross-sections of the T-branch with thermal stratification are examine.

• Membrane Journal
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• v.12 no.1
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• pp.28-40
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• 2002

The primary objective of this study is to elucidate the contribution of the electrostatic and molecula structural properties of an active layer of the thin film compsite (TFC) membranes to fouling tendency. The studies of surface morphology and surface charge were very effective in understanding fouling behaviors of the reverse osmosis (RO) membranes which were the thin film composite type of ployamide. Results of microscopic morphology analyzed by atomic force microscopy (AFM) and surface charge analyzed by electrokinetic analyzer (EKA) showed important factors affecting the fouling of RO membranes. The active layer of the composite membrane possessing realtively neutral streaming charge and less roughness provided a RO membrane with slowly decreasing flux.