• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.5
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• pp.451-456
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• 2000

The development of an integrated technology including fabrication of corrosion defect specimens and their practical use is needed to enhance the reliability of eddy current test for nuclear steam generator tubing. In this paper, the necessity and importance are presented from the viewpoint of the structural integrity, simulation specimens for real defects, and experiences from the destructive examination of pulled tubes. The models for several corrosion defects we also briefly introduced, with the scheme for their practical use.

• Journal of Chest Surgery
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• v.45 no.4
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• pp.225-229
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• 2012

Background: Reoperation of cardiac surgery via median sternotomy can be associated with significant complications. Thoracotomy is expected to reduce the risk of reoperation and to enhance the surgical outcomes. We retrospectively analyzed two operative approaches (thoracotomy vs. sternotomy) in cardiac reoperation. Materials and Methods: From September 2007 to December 2010, 35 patients who required reoperation of the mitral valvular disease following previous median sternotomy were included. Average age of patients was $45.8{\pm}15.4$ years (range, 14 to 76 years) and male-to-female was 23:12. Interval period between primary operation and reoperation was $135.8{\pm}105.6$ months (range, 3.3 to 384.9 months). Results: Comparative analysis was done dividing the patient group into two groups that are thoracotomy group (22 patients) and sternotomy group (13 patients). Thoracotomy group was significantly lower in operative time ($415.2{\pm}90.3$ vs. $497.5{\pm}148.0$, p<0.05), bleeding control time ($108.0{\pm}29.5$ vs. $146.4{\pm}66.8$, p<0.05) and chest tube drainage ($287.5{\pm}211.5mL$ vs. $557.3{\pm}365.5mL$, p<0.05) compared to sternotomy group. Conclusion: The thoracotomy approach is superior to sternotomy in some variables, and it is considered as a valid alternative to repeat median sternotomy in patients who underwent a previous median sternotomy.

• The Journal of the Korea Contents Association
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• v.20 no.1
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• pp.16-24
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• 2020

The study empirically explored factors influencing How storytelling factors in social networking services, SNS, affect consumer response on the uses and gratification theory. conducted an analysis of 120 university students attending universities in the Seoul metropolitan area using an experiment. The results of this study are as follows: first, The storytelling factors, relevance and veracity have a positive effect on clarity. second, it has been shown that only veracity has a positive effect on parai-social interaction with media figures with emotional attachment. third, para-social interactions have been shown to influence content attitudes and orality sequentially. This study deals with the effect of SNS storytelling on the consumer's part, providing practical implications for enhancing content attitudes and word-of-mouth, by increasing para-social interactions with consumers while identifying the components that should enhance the way SNS is delivered in terms of storytelling.

• International Journal of Knowledge Content Development & Technology
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• v.7 no.3
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• pp.67-86
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• 2017

The emergence of smart devices such as smartphones (e.g., iPhone) and tablets (e.g., iPad) may enhance e-learning by increasing communication and collaborative learning outside the classroom. These devices also facilitate the use of online technologies such as Facebook. However, the adaptation of Learning Management System (LMS) services to mobile devices took longer than social networks or online tools such as Facebook and Twitter have already been long used via smartphone. The main purposes of this study are to explore students' skill levels of LMS (Moodle) and their knowledge of online tools or technologies and then examine if there is a correlation between smartphone use and using of online tools and Moodle in learning. The study conducted among 173 students in the Department of Information Studies (DIS) in Oman, using online survey. The study found that most students demonstrated high levels of accessing course/subject materials and regularly engaging with studies of using LMSs. YouTube, Wikipedia and Facebook were clearly recorded as the most popular sites among students while LinkedIn and Academia.edu were two online tools that had never been heard of by over half of the 142 participants. Emailing and searching are recorded the most popular online learning activities among students. The study concluded that students prefer to use smartphone for accessing these tools rather than using it to access LMSs, while a positive correlation was found between the use of these tools and smartphones, but there was no correlation between smartphones and using LMSs.

• Journal of the Korean institute of surface engineering
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• v.52 no.6
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• pp.298-305
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• 2019

We investigated a correlation between morphology and photoelectrochemical properties of TiO₂ nanotubes fabricated by well-controlled anodization processes. Anodization in an ethylene-glycol-based electrolyte solution accelerated the rapid grow rate of TiO₂ nanotubes, but also cause problems such as delamination at the interface between TiO₂ nanotubes and a Ti substrate, and debris on the top of the nanotube. The applied voltages for the anodization of TiO₂ were adjusted to avoid the interface delamination. The heat treatment and the anodizing time were also controlled to enhance the crystallinity of the as-prepared TiO₂ nanotubes and to increase the surface area with the varied length of the anodized TiO₂ nanotubes. Additionally, a 2-step anodization process was utilized to remove the debris on the tube top. The photoelectrochemical properties of TiO₂ nanotubes prepared with the carefully tailored conditions were investigated. By removing the debris on TiO₂ nanotubes, applied bias photon-to-current efficiency (ABPE) of TiO₂ nanotubes increased up to 0.33%.

• Journal of Information Technology Applications and Management
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• v.28 no.1
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• pp.53-61
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• 2021

The year 2020 was a time when the coronavirus infections-19 (COVID-19) caused various changes in society. In particular, the fields that have been conducted face-to-face have been greatly confused by the transition to an online non-face-to-face method, and this is the case with the field of education. There are two main advantages of offline education. The first is that we can improve our understanding through communication with teachers, and the second is that we can develop social skills through interaction with friends. But as online classes progressed due to corona 19, interaction could not be achieved. As a result, the motivation for learning has been reduced due to difficulties in real-time feedback, and the participation rate has been significantly lowered, especially in lower grades, raising concerns about the learning gap that will occur after corona 19. However, there are some cases in which online classes were conducted as effectively as offline classes by utilizing various contents. What they have in common is the use of content. Teachers generally improved the quality of education by linking interesting sights and videos that enhance learning comprehension. The provided video conveys learning-related content into stories, enabling intuitive observation. Many students were already enjoying these videos through VOD (Video on Demand) such as TV and YouTube, they were able to connect their easy access to content and interest in learning. Appropriate use of video content has rather increased the learning effect and should continue after corona 19. Therefore, it is necessary to study methodologies that apply video content efficiently to education. This study looked at the steps that needed content application through the development of education programs, and observed its meaning. Students were curious about the content, motivated to learn and participated in learning on their own. Intuitive learning, conducted through appreciation, play and content production, provided an opportunity to learn on their own in everyday life.

• Tribology and Lubricants
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• v.37 no.6
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• pp.253-260
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• 2021

Metal pipes are used in a wide range of applications, from plumbing systems of large construction sites to small devices such as medical tools. When a liquid is enforced to flow through a metal pipe, a higher flow rate is beneficial for higher efficiency. Using high pressures can enhance the flow rate yet can be harmful for medical applications. Thus, we consider an optimal geometrical design to increase the flow rate in medical devices. In this study, we focus on cannulas, which are widely used small metal pipes for surgical procedures, such as liposuction. We characterize the internal flow rate driven by a negative pressure and explore its dependence on the key design parameters. We quantitatively analyze the suction characteristics for each design variable by conducting computational fluid dynamics simulations. In addition, we build a suction performance measurement system which enables the translational motion of cannulas with pre-programmed velocity for experimental validation. The inner diameter, section geometry, and hole configuration are the design factors to be evaluated. The effect of the inner diameter dominates over that of section geometry and hole configuration. In addition, the circular tube shape provides the maximum flow rate among the elliptical geometries. Once the flow rate exceeds a critical value, the rate becomes independent of the number and width of the suction holes. Finally, we introduce a slippery liquid-infused nanoporous surface (SLIPS) coating using nanoparticles and hydrophobic lubricants that effectively improves the flow rate and antifouling property of cannulas without altering the geometrical design parameter.

• Journal of Chest Surgery
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• v.29 no.1
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• pp.59-62
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• 1996

Chemical pleurodesis with doxycycline has been used during video-assisted thoracoscopic surgery (VATS) as an auxiliary method to enhance therapeutic goal in patients with pneumothorax. However, the therapeutic effect of doxycycline pleurodesis (DP) has not been clearly defined yet. To evaluate the effect of DP, we compared two groups of patients who were given VATS bullectomy from October 1993 to June 1995. Group I composed of 21 patients who received DP and group II composed of 20 patients who did not received DP Doxycycline 500mg with saline 200ml were instilled into the pleural cavity upon a completion of bullec omy, and retained there for 0.5-1 hour and then drained out. The age of group I was 30.9 $\pm$ 20.0 and that of group II was 24.3 $\pm$ 9.49 years. Male to female ratio was 20: I in group I and 20 : 0 in group II. The postoperative indwelling time of chest tube was 5.86 $\pm$ 4.69 days in group I and 3.80 $\pm$ 2.28 days in group II. Seven patients had more than 100m1/day of chest tube drainage on the postoperative third day in group I compared to one patient in group II. Five patients had postoperative indwelling time of chest tube greater than 7 days in group I compared to two in group II. The number of patients who had postoperative fever were 3 in both group, analgesic requirements were 2.19 $\pm$ 2.77 amples in group I and 2.30 $\pm$ 1.95 ambles in group II. Follow-up was done from 2 months to 16 months after surgery. During the follow up periods, four patients had recurrence 2 (9.5%) in group I and 2 (10%) in group II. We conclude that concomitant doxycycline pleurodesis with video-assisted thor coscopic bullectomy In patients with pneumothorax is not necessary.

• Journal of the Korean GEO-environmental Society
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• v.13 no.11
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• pp.61-68
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• 2012

Most widely methods for reinforcement of soil utilized in Korea are anchor method, soil nail method and micro pile method. These methods are classified by the intended use of the structure to be constructed, but the reinforcement of the ground is accomplished contains in common the process of grouting work after inserting the reinforcements. Domestically, gravity grouting has been used mostly so far, but there has always been the risk of insufficient restoration of the loose ground area from the drill holes because the grouting is conducted only by gravity. On the other hand, pressure reinjection grouting may enhance the grouting quality by solving the problem of the existing grouting method considerably since it additionally reinjects grouting through pre-installed tube a certain time after the first grouting. Accordingly, this study evaluated the pullout characteristics by the grouting methods by performing model test on decomposed granite soil, and investigated the support increasing characteristics of reinforcements depending on the curing time, reinjection pressure, and uplift force variation of the pressure reinjection grouting. The result of this research shows that the pressure reinjection grouting demonstrated 1.1~1.3 times of performance of the gravity grouting, and suggests some analysis on optimal water content, reinjection pressure and curing time of the pressure reinjection grouting.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1348-1352
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• 2004

More than 200 Bifidobacterium sp. originated from human intestine were investigated for their ability to produce conjugated linoleic acid (CLA). Of the Bifidobacteria tested, 1 of culture type strain and 12 isolated strains from Korean infants showed CLA producing ability. cis-9, trans-11 octadecadienoic acid presented more than 90% of the total CLA isomers produced by the Bifidobacteria. CLA content in fermented milk by Bifidobacterium sp. KHU 141 increased by 39.6 mg/l00 g, which showed the potential use for producing fermented milk containing high content of CLA. In fermented milk, little changes showed in lauric acid, myristric acid, palmitic acid, oleic acid, and linolenic acid contents, whereas the content of linoleic acid (LA) decreased and the content of CLA increased. Bifidobacterium sp. KHU 141 converted 86.0% and 84.8% of LA consumed to CLA for 24 hr and 48 hr fermentation, respectively. Prolonging incubation from 24 to 48 hours did not appear to enhance CLA formation and CLA producing ability was stable whether bottle, test tube, or fermenter was used for making fermented milk by Bifidobacterium sp. KHU 141.