• Journal of dental hygiene science
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• v.9 no.4
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• pp.405-412
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• 2009

The purpose of this study investigated the effect of Au coating on adhesion between porcelain matrix and metal substructure interface. Titanium, Ni-Cr alloy and Co-Cr alloy are well known as proper metal for the dental restorations. The success of a porcelain fused to metal (PFM) restoration depends upon the quality of the porcelain-metal bond. However, adhesion between dental alloys and porcelain is related to diffusion of oxygen during ceramic firing. The excessive oxidized layers make hard adhesion between dental alloy and ceramic. Ni-Cr and Co-Cr specimens were divided into test and a control group and Titanium specimens were divided into three test groups and a control group. Each group had 20 specimens. The adhesion characteristics of porcelain and metal with Au coating layer and without Au coating layer were observed with scanning electron microscopy(SEM). The adhesion was evaluated by a biaxial flexure test and volume fraction of adherent porcelain was determined by SEM/EDS analysis. Result of this study suggest that Au coating layer is effective barrier to diffuse oxide layer completely protect non-precious alloys from oxidation during the porcelain firing. The SEM photomicrographs of cross-section specimens showed a smooth interface between Au coating layer and metals and porcelain which suggested proper chemical bonding, and no gap, porosity were observed. The mode of failure was mainly adhesive for Ti tested specimens, but mixed failures with adhesive and cohesive were observed in Ni-Cr and Co-Cr specimens. The adhesion between non-precious metals and porcelain would not be improved by Au coating agent. However, It is suggested that the continuous study is required further investigation and development.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.829-836
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• 2016

This study was carried out on Kongju National University and its neighboring area, Mt. Gyeryong national park and Mt. Worak national park in the breeding season of long-tailed tits Aegithalos caudaatus from 2008 to 2012. The result of the inquiry, the nests were found in 15 species of trees, and this result shows me it's not choosy about them. But after having classified them according to the features and analyzed them, long-tailed tits preferred evergreen needleleaf tree and deciduous broad-leaf tree and deciduous bush, especially evergreen needleleaf tree. The concealment rate of long-tailed tits' nests was $11.61{\pm}4.79%]\;4.38{\pm}2.19%$(n=29) in Kongju National University and it's neighboring area, $6.06{\pm}2.31%$(n=43) in Mt. Gyeryong national park and $4.38{\pm}2.19%$(n=32) in Mt. Worak national park. By regional groups, the concealment rates of neighboring nests were almost same, but there are no differences among the areas. The average of the color codes was $26.52{\pm}16.14$(n=32) that those of the nest subtract from those of surroundings of the nest. The nests were procryptic according to their surroundings, and if their nest in a tree were evergreen needleleaf trees, they were made of moss. while if the trees of nest in a tree were yellow because of fungus, made of dried moss, they were yellow, too.

• Archives of design research
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• v.17 no.4
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• pp.211-222
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• 2004

During the 1980s, Textile design achieved a remarkable growth in creating aesthetic effect and in establishing its standing by responding to demands of the time effectively and seeking changes proactively. This was a period when Textile design constructed its modern concept as it was attempting a qualitative improvement through advanced technology, high class, and differentiation. The advent of advanced materials through the development of textile engineering, employment of craft techniques to further cultural and artistic orientation, and restoration of decorativeness in pursuit of sensitivity, all these developments of the 1980s contributed to the rise of above characteristics. In this study, attempts are made to grasp the new trend of Textile design during the 1980s and to review diverse methods of aesthetic creation and plastic possibility which this trend presented for the Textile, and thus to recognize the role of Textile design and its importance in a new light. The new trend of Textile design during the 1980s can be summarized as follows: 1) An appreciation of the creative aspect of the Textile. As attempts are made to emphasize visual and sensitive aspects of the medium, Textile tended to become an object of art itself. 2) A new awareness of the representative and plastic capacity of the fiber material. As attempts are made to develope the creative potential of the Textile, representation of the material tended to become more diversified. 3) A recognition of the Textile as a proper means to deliver the spirit of the time. As the medium accommodates and fuses diverse cultures including traditional culture, more emphasis was place on cultural contents of the Textile. In the process of pursuing these changes, Textile design of the 1980s has also contributed to the creation of new values, laying the groundwork for its emergence as an advanced high value-added industry.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.147-153
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• 2015

Various adverse effects can occur due to direct exposure from toxic substances when toxic materials are used to restore river ecosystems. Thus, this study performed analysis on the development of toxicity in terms of survival and abnormality rates using embryos of Bombina orientalis living in Korea to analyze the toxicity of materials used in the river projects. The results showed that the toxicity in cement (C group) was the strongest whereas the toxicity in plant-based polyurethane (P1 group) was the weakest. Survival rates of B. orientalis embryos were 100%, 94 - 95%, 66 - 89% and 0% in control, P1, polyurethane (P2) and C groups, respectively. Abnormalities of embryos were 10.5%, 5.3 - 10.5%, 26.3 - 27.8% and 35.7% in control, P1, P2 and C groups, respectively. Furthermore, we verified that having a sufficient curing time reduced toxic substances that were extracted. The above result suggest that cement and polyurethane hamper the early development of amphibians. In conclusion, it is highly important to review biological safety with respect to the selection of materials used to restore rivers. This study shows the importance of the selection of eco-friendly materials and processes.

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.27-36
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• 2016

Low Impact Development (LID) techniques are eco-friendly storm water management process for water circulation restoration and non-point pollutant reduction. In this study, four LID techniques (Small constructed wetland, Infiltration trench box, Infiltration trench, Vegetated swale) were selected and installed as a real size at the real site. All facilities were evaluated as monitoring under the real environmental climate situation and an artificial rain with exceeding design rainfall. In various rainfall, runoff reduction efficiency and non-point pollutant removal efficiency are increased to the bigger Surface Area of LID (SA)/Catchment Area (CA) ratio and the bigger Storage Volume of LID (SV)/Catchment Area (CA) ratio. Runoff did not occur at all rainfall event (max. 17.2 mm) in infiltration trench and vegetated swale. But Small constructed wetland was more efficient at less than 10 mm, a efficiency of infiltration trench box was similar at different rainfall. Although different conditions (such as structural material of LID, rainfall flow rate, antecedent dry periods), LID techniques are good effects not only water circulation improvement but also water quality improvement.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.565-577
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• 2019

The purpose of this study was to understand the factors influencing the decline and the patterns of changes in Abies nephrolepis populations on Mt. Seorak. We installed permanent quadrats in the areas of the Gwittagicheongbong (peak), Gwanmoneungseon (ridge), and the Seorak Falls and have monitored the community structure, population dynamics, radial growth, and vitality in the quadrats since 2009. Excluding the Seorak Falls, the three research sites showed a three-layer structure in which the low-tree layer forms the canopy. Major tree species were Khingan fir, Korean arborvitae, Mongolian oak, Erman's birch, and Korean maple. The significance of Khingan fir in Seorak Falls decreased from 45.3% in 2009 to 36.8% in 2018. The number of shoots ($DBH{\geq}5cm$) was highest at 1,800 individuals/ha and 1,700 individuals/ha at the Gwittagicheongbong 2 and the Gwanmoneungseon, respectively. The mortality rates over the past 10 years were very high, at 38.3% and 35.3%, respectively, in the Gwittagicheongbong 1 and Seorak Falls. The most stable inverse J-shaped distribution in the Gwittagicheongbong 1 area was shown in the size-frequency distribution of the Khingan fir populations. The average annual ring growth of the Khingan fir was 0.96 ~ 1.73 mm/year, and the ring growth tended to decrease in the areas of Gwittagicheongbong 1, Gwanmoneungseon, and Seorak Falls, where the vitality was low. If the monitoring process continues, it will be possible to obtain basic data for the conservation and management of subalpine vegetation.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.5
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• pp.203-211
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• 2021

Octacalcium phosphate(OCP, Ca₈H₂(PO₄)₆·5H₂O) is one of biodegradable calcium phosphate materials with osteoconductivity and biocompatibility. It has the advantage of rapid bone formation and resorption due to the property of stimulating stromal cells to differentiate into osteoblasts. However, if OCP is inserted in body, it is immediately decomposed without maintaining of its shape as scaffolds due to their weak cohesive force between powder. On the other hand, hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂), which has a crystal structure similar to that of OCP, remains in the body without decomposition until the bone defect is restored. In this study, the degradation behavior of OCP/HA disc with different amount of HA in SBF (simulated body fluid) solution was characterized in terms of the weight loss, pH variation and microstructure change with immersion duration in SBF solution. As a result, the OCP/HA disc was not quickly decomposed and maintained its own shape for 2 weeks regardless of HA content. In particular, the surface of 40HA specimen was uniformly dissolved and then CDHA (calcium deficient hydroxyapatite) phase were formed onto the surface of disc after 7 days in SBF solution. It would be suggested that the 40HA specimen would be suitable candidate material as the scaffolds for the restoration of bone defect.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.39 no.2
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• pp.39-49
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• 2021

This study was conducted to establish practical goals for the viewing environment and interpretation and delivery system of cultural heritage and to create an viewing environment according to the classification of cultural heritage types, and the conclusions reached are as follows. First, five goals were set based on the international basic principles of the cultural heritage viewing environment and interpretation and delivery system. Second, based on the set goals, cultural heritage was classified into the first type 'disappeared and hidden heritage', the second type 'stuffed memory heritage', and the third type 'living memory heritage'. Third, the directions for creating the viewing environment for each type of cultural heritage were suggested. The first type has to be able to properly convey cultural heritage to visitors through excavation and digital technology. The second type needs a plan to deliver tangible and intangible values by combining various digital technologies with actual cultural heritage. The third type should emphasize the role of local residents in effectively enjoying the tangible and intangible values ??that already exist. Fourth, it proposed comprehensive considerations in the establishment of the cultural heritage viewing environment and interpretation and delivery system. Based on dynamic and sustainable heritage management, cultural heritage viewing should be valuable, satisfying and enjoyable. In addition, local communities should be actively involved, and tourism and conservation activities should be able to benefit the community. Establishment of a viewing environment should protect and strengthen the authenticity of cultural heritage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.50-55
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• 2019

Recently Ransomware attacks are continuously increasing, and new Ransomware, which is difficult to detect just with a basic vaccine, continuously has its upward trend. Various solutions for Ransomware have been developed and applied. However, due to the disadvantages and limitations of existing solutions, damage caused by Ransomware has not been reduced. Ransomware is attacking various platforms no matter what platform it is, such as Windows, Linux, servers, IoT devices, and block chains. However, most existing solutions for Ransomware are difficult to apply to various platforms, and there is a limit that they are dependent on only some specific platforms while operating. This study analyzes the problems of existing Ransomware detection solutions and proposes the onboard module based Ransomware detection system; after the system defines the function of necessary elements through analyzing requirements that can actually reduce the damage caused by the Ransomware from the viewpoint of users, it supports various OS without pre-installation and is able to restore data even after being infected. We checked the feasibility of each function of the proposed system through the analysis of the existing technology and verified the suitability of the proposed techniques to meet the user's requirements through the questionnaire survey of a total of 264 users of personal and corporate PC users. As a result of statistical analysis of the questionnaire results, it was found that the score of intent to introduce the system was at 6.3 or more which appeared to be good, and the score of intent to change from existing solution to the proposed system was at 6.0 which appeared to be very high.

• Journal of Conservation Science
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• v.34 no.6
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• pp.443-458
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• 2018

An archive is a collection of documents or records. Currently, most archived documents are made of paper. Paper is susceptible to biological damage and deterioration due to its material properties. To control the biological damage, treatment with chemical disinfectants and control of the storage environment are often used. In government-controlled bulk public archives, all documents are chemically sterilized before storage. However, an extremely large quantity of public records have been produced, and storage space and conservation management are gradually reaching their limits. In this study, 60 species of microbes were identified using a genetic method. We successfully applied the adenosine triphosphate (ATP) bioluminescence method to detect microbial contamination on paper documents. A calibration curve of the ATP bioluminescence as a function of the microbe quantity was obtained, and the microbial activity on non-sterilized paper archives from 1951 was analyzed using an ATP luminometer. It was found that the microbial activity was suppressed or reduced in climate-controlled storage environments at $22^{\circ}C$ and 55% relative humidity. We anticipate that these results will be used to establish selective sterilization systems for government-controlled bulk public archives.