• Journal of Energy Engineering
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• v.29 no.1
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• pp.52-57
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• 2020

OLM(On-Line Maintenance) is PM(Preventive Maintenance) activity of safety related equipment during running of Nuclear Power Plants. Korea Hydro & Nuclear Power-co.(KHNP) and regulator institute already reviewed the adoption of on-line maintenance in 2010 but now because of changing conditions of nuclear industry it has been halted. Even though that, OLM is one of the most effective programs to enhance safety and operability of Nuclear power plant. Therefore this paper introduce the strengths of OLM and explain why we should apply to Nuclear power plant.

• Smart Structures and Systems
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• v.24 no.5
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• pp.617-630
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• 2019

Currently most of the vision-based structural identification research focus either on structural input (vehicle location) estimation or on structural output (structural displacement and strain responses) estimation. The structural condition assessment at global level just with the vision-based structural output cannot give a normalized response irrespective of the type and/or load configurations of the vehicles. Combining the vision-based structural input and the structural output from non-contact sensors overcomes the disadvantage given above, while reducing cost, time, labor force including cable wiring work. In conventional traffic monitoring, sometimes traffic closure is essential for bridge structures, which may cause other severe problems such as traffic jams and accidents. In this study, a completely non-contact structural identification system is proposed, and the system mainly targets the identification of bridge unit influence line (UIL) under operational traffic. Both the structural input (vehicle location information) and output (displacement responses) are obtained by only using cameras and computer vision techniques. Multiple cameras are synchronized by audio signal pattern recognition. The proposed system is verified with a laboratory experiment on a scaled bridge model under a small moving truck load and a field application on a footbridge on campus under a moving golf cart load. The UILs are successfully identified in both bridge cases. The pedestrian loads are also estimated with the extracted UIL and the predicted weights of pedestrians are observed to be in acceptable ranges.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.164-169
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• 2018

A detailed fatigue evaluation procedure was developed to mitigate the excessive conservativeness of the conventional environmental fatigue evaluation method for the pressurizer spray line elbow of domestic new nuclear power plants. The pressurizer spray line is made of austenitic stainless steel, which is relatively sensitive to the environmentally assisted fatigue, and has a low degree of design margin in terms of environmentally assisted fatigue due to the thermal stratification phenomenon on the pipe cross section as a whole or locally. In this study, to meet the environmental fatigue design requirements of the pressurizer spray line elbow, the new environmental fatigue evaluation has been performed, which used the ASME Code NB-3200-based detailed fatigue analysis and the environmental fatigue correction factor instead of the existing NB-3600 evaluation method. As a result, the design requirements for environmentally assisted fatigue were met in all parts of the pressurizer spray line elbow including the fatigue weakened zones by thermal stratification.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.73.1-73.1
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• 2010

Using the spectroscopic data secured with the Hamilton Echelle Spectrograph attached to a 3-m telescope at the Lick Observatory, we derived the expansion velocities from various line profiles in the 3600 $\AA$ to 10,000 $\AA$ based on the full width at half maximum and double peak of the high dispersion line profiles. The symmetrical shapes of the permitted line profiles indicate that the permitted line zone is symmetrical e.g., a spherical shell or bipolar + torus structures, which might be evidence of relatively recent ejection from the central star. Most other stronger forbidden lines might be coming from a main shell which appears as a bilateral symmetrical morphology, seen in HST and other ground-based telescopic images. The overall expansion velocities of this main shell structure that are responsible for most lines, seem to show the Hubble type expansion, i.e., accelerating shell. The faster expansion velocities of the permitted OII, NII, NIII and perhaps CII lines that do not suit to the Hubble type expansion, imply the existence of a somewhat smaller inner shell inside the outer main shell. We conclude that the nebular shell consists of a swiftly expanding inner shell and an outer normal shell excited by a central star of about 55,000K. The former compact zone appears to be responsible for the permitted C, N, and O lines while the latter extended shell appears to be responsible for H, He, and forbidden lines. We present some evidence that NGC 6833 be a member of the Galactic halo.

• Journal of The Korean Astronomical Society
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• v.34 no.1
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• pp.17-24
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• 2001

We have studied the central parts of M82, which is a well-known infrared luminous, starburst galaxy, by analyzing archival data from the Infrared Space Observatory (ISO). M82 was observed at 11 positions covering $\pm$45" from the center along the major axis. We analyzed 4 emission lines, [ArIII] 8.99 ${\mu}m$, $H_2$ 17.034 ${\mu}m$, [FeII] 25,98 ${\mu}m$, and [SiII] 34,815 ${\mu}m$ from $SWSO_2$ data. The integrated flux distributions of these lines are quite different. The $H_2$ line shows symmetric twin peaks at $\~$18" from the center, which is a general characteristic of molecular lines in starburst or barred galaxies. This line appears to be associated with the rotating molecular ring at around $\~$200 pc just outside the inner spiral arm. The relative depletion of the $H_2$ line at the center may be due to the active star formation activity which dissociates the $H_2$ molecules. The other lines have peaks at the center and the distributions are nearly symmetric. The line profiles are deconvolved assuming that both intrinsic and instrumental profiles are Gaussian. The velocity dispersion outside the core is found to be $\~50 km s^{-1}$. The central velocity dispersion is much higher than $50 km s^{-1}$, and different lines give different values. The large central velocity dispersion ($\sigma$) is mostly due to the rotation, but there is also evidence for a high $\sigma$ for [ArIII] line. We also generated position-velocity maps for these four lines. We found very diverse features from these maps.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.43.2-44
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• 2020

We have carried out high-resolution near-infrared (NIR) spectroscopic observations toward 16 Galactic supernova remnants (SNRs) showing strong H2 emission features. A dozen bright H2 emission lines are clearly detected for individual SNRs, and we have measured their central velocities, line widths, and fluxes. For all SNRs except one (G9.9-0.8), the H2 line ratios are well consistent with that of thermal excitation at T~2000 K and their line widths are broader than ~10 km s-1, indicating that the H2 emission lines are most likely from shock-excited gas and therefore that they are physically associated with the remnants. The kinematic distances to the 15 SNRs are derived from the central velocities of the H2 lines using a Galactic rotation model. We derive for the first time the kinematic distances to four SNRs: G13.5-0.2, G16.0-0.5, G32.1-0.9, G33.2-0.6. Among the rest 11 SNRs, the central velocities of the H2 emission lines for six SNRs are well consistent (±5 km s-1) with those obtained in previous radio observations, while for the other five SNRs (G18.1-0.1, G18.9-1.1, Kes 69, 3C 396, W49B), they are significantly different. We discuss the velocity discrepancies in these five SNRs. In G9.9-0.8, the H2 emission shows non-thermal line ratios and very narrow line width (~4 km s-1), and we discuss its origin.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1456-1458
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• 1999

As the system reliability of power supply is highly increased, we need distribution maintenance techniques without any power interruption. To meet such an increasing demand, a groat deal of hot line work on the high voltage overhead distribution lines has been carried out. In this regard, Hot line work techniques has being applied widely. However, hot line work techniques can not cover all kinds of work without interruption. To cope with those problems, the temporary power supply work technique such as bypass cable truck technique, temporary switch technique and mobile transformer technique was developed and applied. This paper presents the most optimal method according to distribution work contents through the comparison and analysis the characteristis and problems of the existing various work techniques. Also this paper suggested the countermeasers of the prsent problems.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.35-43
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• 2012

The Government is implementing the safety measures for pedestrian in living zone to decrease the traffic accident casualties in half. It is urgently to study the guideline because it contains to make the guideline of a median strip in City to prevent the violation of central line and jaywalking on the main contents. So, this study analyzed the pedestrian accidents and the violation of central line, and studied the type of a median strip, the installation guideline through studying the minimum crossing. Consequently, this study found out that a median strip which revised the attention inducement stick to decrease jaywalking could not have the strong prevention function of a crash barrier, so if it happens separation after the collision between vehicles, it induced the secondary accidents, and could take negative effects on traffic safety. In consideration of driving safety, this study analyzed that if it installs a median stirp, it has to ensure one meter, and such a thing could prevent the separation of lane or damage of facilities. However, if it is hard to ensure the space because of narrow road width, it could install a median strip in case of installing the road surface mark 0.5m. And the installation of the attention inducement stick or a median strip on the central line could be possible to induce the violation of central line, thus it is desirable not to install only anythings but also raised pavement markers.

• Clinical and Experimental Pediatrics
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• v.62 no.3
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• pp.79-84
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• 2019

Newborn infants, including premature infants, are high-risk patients susceptible to various microorganisms. Catheter-related bloodstream infections are the most common type of nosocomial infections in this population. Regular education and training of medical staffs are most important as a preventive strategy for central line-associated bloodstream infections (CLABSIs). Bundle approaches and the use of checklists during the insertion and maintenance of central catheters are effective measures to reduce the incidence of CLABSIs. Chlorhexidine, commonly used as a skin disinfectant before catheter insertion and dressing replacement, is not approved for infants <2 months of age, but is usually used in many neonatal intensive care units due to the lack of alternatives. Chlorhexidine-impregnated dressing and bathing, recommended for adults, cannot be applied to newborns. Appropriate replacement intervals for dressing and care sets are similar to those recommended for adults. Umbilical catheters should not be used longer than 5 days for the umbilical arterial catheter and 14 days for the umbilical venous catheter. It is most important to regularly educate, train and give feedback to the medical staffs about the various preventive measures required at each stage from before insertion to removal of the catheter. Continuous efforts are needed to develop effective and safe infection control strategies for neonates and young infants.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7747-7752
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• 2014

Kr$\ddot{u}$ppel-like factor 4 is a transcription factor which plays an important role in development and progression of various carcinomas. Curcumin characterized by excellent anti-cancer properties is regarded as a serviceable natural compound used in carcinoma therapy. This study aimed at exploring the impact of KLF4 overexpression in cooperation with curcumin on the proliferation, apoptosis and invasion of human gastric carcinoma BGC-823 cells. Flow cytometry analysis, CCK-8 assays, transwell assays and Western blot results showed that KLF4 overexpression combined with curcumin had significant anti-proliferation, pro-apoptosis and anti-invasion effects on BGC-823 cells. We also found that KLF4 had synergistic effects with curcumin, better promoting apoptosis and inhibiting proliferation and invasion of gastric carcinona cells. These results indicate that KLF4 could be used as a potential therapeutic target; curcumin could act as an auxiliary and provide a promising therapeutic strategy in stomach cancer.