• Carbon letters
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• v.12 no.3
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• pp.177-179
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• 2011

The use of carbon nanotubes (CNTs) as a reinforcing material in a polymer matrix has increased in various industries. In this study, the flexural behavior of CNT-modified epoxy/basalt (CNT/epoxy/basalt) composites is investigated. The effects of CNT modification with silane on the flexural properties of CNT/epoxy/basalt composites were also examined. Flexural tests were performed using epoxy/basalt, oxidized CNT/epoxy/basalt, and silanized CNT/epoxy/basalt multi-scale composites. After the flexural tests, the fracture surfaces of the specimens were examined via scanning electron microscopy (SEM) to investigate the fracture mechanisms of the CNT/epoxy/basalt multi-scale composites with respect to the CNT modification process. The flexural properties of the epoxy/basalt composites were improved by the addition of CNTs. The flexural modulus and strength of the silane-treated CNT/epoxy/basalt multi-scale composites increased by approximately 54% and 34%, respectively, compared to those of epoxy/basalt composites. A SEM examination of the fracture surfaces revealed that the improvement in the flexural properties of the silane-treated CNT/epoxy/basalt multi-scale composites could be attributed to the improved dispersion of the CNTs in the epoxy.

• Structural Engineering and Mechanics
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• v.49 no.2
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• pp.261-271
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• 2014

This paper reported an experimental study on creep behaviors of PVB and Ionoplast laminated glass (LG) under load duration of 30 days. The tests were carried out in room temperature ($23^{\circ}C$). The study revealed that after sustaining loads for 30 days, the mid-span deflection of PVB LG increased by almost 102% compared with its short term deflection, while that of Ionoplast LG approximately increased by 14%; composite effects between two glass plies in PVB LG gradually reduced with time, but did not fully vanish at the 30th day; two glass plies in Ionoplast LG on the other hand was able to withstand loads as an effective composite section during the entire loading period; the creep behaviors of both LG were not finished yet at the 30th day. In addition to this, also studied was the varying of the bending stresses of PVB and Ionoplast LG under load duration of 2 hours. The tests were carried out in ambient temperatures of $30^{\circ}C$, $50^{\circ}C$ and $80^{\circ}C$ respectively. It was found that under a given load, although the bending stresses of both LG increased with increasing temperature, for PVB LG the increasing rate of the bending stress decreased with increasing temperature, while for Ionoplast LG the increasing rate of the bending stress increased with increasing temperature.

• ETRI Journal
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• v.32 no.6
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• pp.871-880
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• 2010

Many applications dealing with image management need a technique for removing duplicate images or for grouping related (near-duplicate) images in a database. This paper proposes a concentric circle-based image signature which makes it possible to detect near-duplicates rapidly and accurately. An image is partitioned by radius and angle levels from the center of the image. Feature values are calculated using the average or variation between the partitioned sub-regions. The feature values distributed in sequence are formed into an image signature by hash generation. The hashing facilitates storage space reduction and fast matching. The performance was evaluated through discriminability and robustness tests. Using these tests, the particularity among the different images and the invariability among the modified images are verified, respectively. In addition, we also measured the discriminability and robustness by the distribution analysis of the hashed bits. The proposed method is robust to various modifications, as shown by its average detection rate of 98.99%. The experimental results showed that the proposed method is suitable for near-duplicate detection in large databases.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.4
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• pp.499-510
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• 2007

This study examined the intake patterns and information-seeking behaviors of elderly individuals with regard to health foods, according to sociodemograhic characteristics, awareness of health, and concerns and awareness about health foods. The data were collected from 421 elderly living in Seoul, Busan, Daegue, Daejon, and Gwangju, between January 17th and February 23rd, 2006. Frequencies and chi-square tests were conducted using SPSS Windows. The results are as follows: The respondents were highly concerned about their own health as well as health foods, and individuals primarily took nutritional supplements and glucosamine containing products. In addition, they had taken various health-improving foods. Most had intentionally consumed at least one health food, in order to maintain a condition of health. According to chi-square tests, women were more likely to consume health foods than men. The most important sources of information regarding health foods were family, relatives, and friends. Some respondents answered they had difficulties in obtaining and understanding health food-related information. Many respondents desired to get health food information regarding efficacy from TV, radio, and newspapers, as well as doctors, pharmacists, and dieticians.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.3
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• pp.513-524
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• 2015

The effects of four different oligosaccharides with 2, 4, 6% (w/w) (fructo-oligosaccharide, xylo-oligosaccharide, chito-oligosaccharide and soybean-oligosaccharide) on gelatinization and retrogradation of sulgidduks (Korean rice cake) were examined. The amylograph results of rice flour showed that chito-oligosaccharide hastened gelatinization, and delayed retrogradation. Blue value results of chito-oligosaccharide added sulgidduks showed retarded retrogradation during storage (1, 2 and 3 days). Chitooligosaccharide and xylo-oligosaccharide added sulgidduks showed significantly lower hardness during storage. Lightness (L) decreased and redness (a) and yellowness (b) increased with increasing oligosaccharide amounts. In the sensory evaluation of sulgidduks, color of fructo-oligosaccharide added sulgidduks obtained the highest score among oligosaccharide added sulgidduks. During storage, xylo-oligosaccharide and fructo-oligosaccharide added sulgidduks had higher flavor, taste, graininess and overall quality scores than the control. Physicochemical tests showed that chito-oligosaccharide retarded retrogradation, whereas chitooligosaccharide- added sulgidduks had low scores in sensory tests due to aftertaste of chito-oligosaccharide. To improve the sensory quality of chito-oligosaccharide added sulgidduks, mixtures of chito-oligosaccharide with xylo-oligosaccharide and fructooligosaccharide were applied at ratios of 3%:3%, 2%:4% and 1%:5%, respectively. The addition of chito-oligosaccharide and xylo-oligosaccharide at ratios of 2%:4% and 1%:5% to sulgidduks showed relatively high scores in the sensory evaluation retarding retrogradation.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.85-93
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• 2015

In this study, tensile tests were performed on aluminum alloys (AA6061 and AA6082) to investigate their mechanical behaviors at cryogenic temperatures. The temperature was varied from 110 K up to 293 K, and quasi-static strain rates of 10⁻⁴ s⁻¹ −10⁻² s⁻¹ were taken into account for the tests. The experimental results were analyzed to find the dependence on the temperature, strain rate, and fractured surfaces. As a result, it was found that the strength and elongation of the aluminum alloys were improved when the temperature was decreased. In addition, it was confirmed that the mechanical behaviors of the aluminum alloys were not dependant on the strain rate. Under a tensile load, two types of fractures were seen in the aluminum alloys: cup-cone (AA6061) and shear (AA6082).

• Steel and Composite Structures
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• v.18 no.4
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• pp.925-946
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• 2015

This paper presents a new cost-effective hybrid GFRP-Concrete deck system that the GFRP panel serves as both tensile reinforcement and stay-in-place form. In order to understand the fatigue behavior of such hybrid deck, fatigue test on a full-scale specimen under sagging moment was conducted, and a series of static tests were also carried out after certain repeated loading cycles. The fatigue test results indicated that such hybrid deck has a good fatigue performance even after 3.1 million repeated loading cycles. A three-dimensional finite element model of the hybrid deck was established based on experimental work. The results from finite element analyses are in good agreement with those from the tests. In addition, flexural fatigue analysis considering the reduction in flexural stiffness and modulus under cyclic loading was carried out. The predicted flexural strength agreed well with the analytical strength from finite element simulation, and the calculated fatigue failure cycle was consistent with the result based on related S-N curve and finite element analyses. However, the flexural fatigue analytical results tended to be conservative compared to the tested results in safety side. The presented overall investigation may provide reference for the design and construction of such hybrid deck system.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.18 no.4
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• pp.463-471
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• 2011

Purpose: The purpose of this study was to develop nursing practice guidelines for water treatment system used in hemodialysis and to evaluate the guidelines by applying them in practice. Method: The first draft for the guidelines was developed based on advice and recommendations obtained from procedure review of critical literature. The draft was modified through evaluation by an expert group and pilot application to practice. The final draft was evaluated by the expert group using the AGREE instrument (Appraisal of Guidelines for Research and Evaluation). Results: For the pilot test using the draft guidelines, 144 samples were collected from the water treatment system and hemodialysis machines. Results showed no bacteria. Endotoxin tests and chemical tests passed the criteria. After revision of the draft guidelines and additions to the draft guidelines, the final draft was confirmed. The quality of the final draft was evaluated by 4 experts using the AGREE instrument. The mean standard score was 76.9% for the 19 items. Conclusion: The clinical guidelines developed in this research can be utilized as systematic and scientific guidelines for water treatment systems used in hemodialysis. In addition, the results of the research can contribute to improving care services.

• Journal of Korean Academy of Nursing
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• v.37 no.4
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• pp.442-452
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• 2007

Purpose: The purpose of this study was to develop an online education on death, 'successful life, and beautiful death' for university students and to evaluate students' changes regarding perception of self and death. Method: A quasi-experimental design was used with one experimental group pre-post test. Subjects were 154 students who enrolled for online education about death for 16 weeks. SPSS/WIN 12 was used for analyzing data. Result: The results of the study clearly indicated this class had positive effects on students' perception of death-related concepts, attitudes toward death, and self-concept, showing statistically significant higher scores in post-tests than in pre-tests. In addition, the result of class evaluations showed a positive response, Conclusion: Findings suggested that this online education about death was effective to change students' perceptions of death related knowledge, attitude toward death, and self-concept. Recommendations for further studies were provided.

• Explosives and Blasting
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• v.36 no.2
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• pp.10-18
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• 2018

The shaped charge is used in explosive demolition of steel frame structure, but it was often not used because it was limited to use or impossible to supply at domestic and foreign. To solve this problem, we needed a device that could generate matal jets using industrial explosive. In this study, we made a charging container, which metal jets were generated when explosives were detonated. Cutting performance tests were carried out to evaluate the effect of cutting of a charging container on a steel plate of 25mm thickness. In addition, we compared the results between the numerical simulation of penetration process and cutting performance tests and then was evaluated a cutting performance for steel plates of 35mm and 70mm thickness.