• Journal of Dental Rehabilitation and Applied Science
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• 제37권1호
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• pp.1-15
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• 2021

Additive manufacturing (AM) for dental materials can produce more complex forms than conventional manufacturing methods. Compared to milling processing, AM consumes less equipment and materials, making sustainability an advantage. AM can be categorized into 7 types. Polymers made by vat polymerization are the most suitable material for AM due to superior mechanical properties and internal fit compared to conventional self-polymerizing methods. However, polymers are mainly used as provisional restoration due to their relatively low mechanical strength. Metal AM uses powder bed fusion methods and has higher fracture toughness and density than castings, but has higher residual stress, which requires research on post-processing methods to remove them. AM for ceramic use vat polymerization of materials mixed with ceramic powder and resin polymer. The ceramic materials for AM needs complex post-processing such as debinding of polymer and sintering. The low mechanical strength and volumetric accuracy of the products made by AM must be improved to be commercialized. AM requires more research to find the most suitable fabrication process conditions, as the mechanical properties and surface of any material will vary depending on the processing condition.

• Journal of Dental Rehabilitation and Applied Science
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• 제37권4호
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• pp.232-243
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• 2021

Purpose: The purpose of this study was to evaluate the shear bond strength of various 3D printed denture base resins and the conventional denture base resin to various denture relining materials. Materials and Methods: For denture base materials, a heatcured (Vertex RS) and two types of 3D printed DENTCA Denture base II, NextDent^TM Base) were used. And 4 types denture relining materials (Tokuyama Rebase II fast, Kooliner, Denture Liner, Denture Liner, Lang Jet Denture Repair Kit) with different components were used. It was classified into 12 groups. Adhesion was performed between the resin base and the relining materials in accordance with ISO/TS 11405 standard. The shear bonding strength was measured, and then the adhesion interface was observed with a stereoscopic microscope and a scanning electron microscope. The fracture pattern was investigated through the analysis of the fragment. Results: In the 3D printed denture resin group, the shear bonding strength with relining materials was significantly lower than that of the heat-cured resin group (P < 0.05). The group of polymethyl methacrylate -based relining materials, high shear bonding strength was shown regardless of the type of denture. As for the fracture pattern, adhesive fracture appeared in most groups, and cohesive, mixed fracture appeared in some groups. Conclusion: The polymethyl methacrylate -based denture relining materials showed high shear bonding strength values compared to other denture relining materials. But, for direct methods, it is considered advantageous in terms of shear bonding strength to use a isobutyl methacrylate-based denture relining materials.

• Conservation Science in Museum
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• 제27권
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• pp.67-90
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• 2022

A C-46 transport aircraft, which can be thought of as a large cultural heritage item from the modern period, was subjected to paint analysis and conservation treatment in preparation for its exhibition. The C-46 is the first aircraft ever dispatched to overseas combat zones by the Korean Air Force and carried out missions during the Vietnam War. The aircraft is mainly made of aluminum and shows signs of corrosion on its surface, including pitting and etching, as well as gray and white powdery attachments. In the analysis of the paint, diatomite(SiO₂·nH₂O) was confirmed in the red paint, titanium dioxide(TiO₂) was identified in the white paint, black iron oxide(Fe₃O₄) was detected in the black paint, and colcothar(Fe₃O₄) mixed with putty was confirmed in the blue paint. Infrared spectroscopy revealed the use of alkyd resin in the paint on the main body and nitrocellulose in the Taegeuk pattern. During the conservation treatment, mechanical cleaning, such as sanding, was conducted to remove paint and varnish from the surface. Corrosion was removed by sanding and cleaning with chemical solvents, and new paints and varnishes were applied. Through the paint analysis and conservation treatment, the aircraft was made available for exhibition in a stable condition.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제15권2호
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• pp.95-102
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• 2022

It is a study for the evaluation of the stability of the distribution automation system for the expansion of renewable energy. Through the Renewable Energy 3020 Implementation Plan, the government plans to expand new renewable energy and convert it to participatory energy that improves the quality of life of the people by 2030. The government has set a target of 20% of domestic supply energy for renewable energy generation by 2030. It is planning to establish more than 95 percent of its new facilities with clean energy such as solar power and wind power. By expanding the supply of renewable energy, new energy businesses and distributed power industry were fostered, and short-distance, low-voltage, and small-scale power generation were rapidly expanded rather than large-scale power development in the past. Due to this demand, the importance of power distribution facility operation has emerged and the need for distribution automation system is increasing. This paper discusses the development of a power distribution simulator for the performance and function evaluation of power distribution automation systems and presents the results of an interlocking test with the power distribution automation system. In order to introduce an advanced system into the power distribution system, it is necessary to take advantage of the transmission and distribution system. The DNP3.0 protocol is used in the distribution system and the IEC61850 protocol is used in the transmission and distribution system. It was concluded that the functions and performance of operations were satisfied when these two protocols are mixed and used in the distribution automation system.

• Journal of the Korean Association of Geographic Information Studies
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• 제24권4호
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• pp.113-126
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• 2021

This study was conducted to analyze the forest status and deforestation area changes of the DMZ region in North Korea based on satellite images. Using growing and non-growing season's RapidEye satellite images, land cover of the North Korean DMZ was classified into stocking land(conifer, deciduous, mixed), deforested land(unstocked mountain, cultivated mountain, bare mountain), and non-forest areas. Deforestation rates in the Yeonan-baecheon, Beopdong-Pyeonggang, Heoyang-Geumgang and Tongcheon-Goseong district were calculated as 14.24%, 16.75%, 5.98%, and 16.63% respectively. Forest fire and land use change of forest were considered as the main causes of deforestation of DMZ. Changes in deforestation area were analyzed through Google Earth images. As a results, it was shown that the area of deforestation was on a decreasing trend. This study can be used as basic data for establishing inter-Korean border region's forest cooperation strategies by providing forest spatial information on the North Korea's DMZ.

• Journal of the Korean Recycled Construction Resources Institute
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• 제10권3호
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• pp.314-320
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• 2022

The function of reinforcing fibers used in building materials is to maintain resistance to bending loads and to function for cracking caused by drying shrinkage. High-density fiber-cement composites are mainly used for linear plates and are used to increase bending resistance. Therefore, tensile properties, bonding strength with cement hydrate, alkali resistance, and the like are required. Recently, as the non-combustible performance has been strengthened, a function to minimize the occurrence of sparks during high-temperature heating has been added. Therefore, the use of organic fibers is limited. In this study, a study was conducted to replace polypropylene used as reinforcing fiber with hemp fiber with excellent heat resistance. Hemp fibers have excellent heat resistance, good affinity with cement, and excellent alkali resistance. Based on the total volume of polypropylene fibers used in the existing formulation, the non-combustible performance was compared and evaluated by using hemp fibers instead of the polypropylene fibers, and basic physical properties such as flexural strength were tested. As a result of conducting a non-combustibility and physical property test using hemp fibers with a fiber length of 7 mm using 2 % and 3 % by weight, it was found that there is no remaining time of the flame, and the flexural strength can be secured at 95 % level of the existing polypropylene fiber.

• Journal of Korea Entertainment Industry Association
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• 제14권7호
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• pp.343-362
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• 2020

English is a stress-timed language that has a phonetic system in which the speech is restructured by stress changes. On the other hand, Korean is a syllable-timed language in which each syllable is pronounced at almost the same length and intensity, and Korean and English have distinctly different metrical systems in general speech. However, as the language of the lyrics in K-Pop music is mixed in both languages, Korean and English, the Korean lyrics in K-Pop music have a metrical system by stress changes as in English. The writer's view is that the change in the metrical structure of Korean lyrics is inevitable in order to sustain the new Korean Wave. Therefore, in this study, dance music - a major genre of K-Pop music that focuses on rhythm expression - is classified into 1998, 2003, and 2009 according to the changes in the Korean Wave, and the metrical structure of each period is compared and analyzed. Based on this, the current K-Pop metrical structure features are derived and the K-Pop Korean writing method is proposed that deviates from the existing limited writing method which allocates one syllable per note. The author hopes this research will be used as a methodology for writing lyrics in Korean songs in K-Pop, as well as a way to encourage the use of Korean lyrics.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제67권3호
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• pp.164-171
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• 2022

We studied the influence of Hanwoo (Korean native cattle) manure compost soil application on the growth and yield of maize (Zea mays L.). We compared the soil application of chemical fertilizer (CF), commercial manure (CM), Hanwoo manure (HM), and the mixed Hanwoo manure and chemical fertilizer (HM + CF). CF application showed faster tasseling and silking dates compared to the other treatments. During the early plant growth stage of maize, CF application resulted in taller plant height, However, during later growth stages (55 days after transplanting). HM (226.0 cm) and HM + CF (230.0 cm) treatment resulted in taller plant height compared to CF (216.2 cm). Post-harvest measurement results showed that, the ear length was longer in HM (22.13 cm) and HM + CF (22.70 cm) compared to others, while ear diameter, ear weight, and 100-grains weight showed no significant difference among CF, HM, and HM + CF groups. The use of HM resulted in delayed growth during the early stages of plant development compared to CF. However, crop productivity markers of ear weight and ear diameter showed no significant difference compared to CF. Thus, HM treatment was comparable to CF treatment in maize cultivation.

• Journal of Radiopharmaceuticals and Molecular Probes
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• 제7권2호
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• pp.105-111
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• 2021

⁸⁹Zr is a positron-emitting radioisotope, which has known as well-suited radioisotope for use in a monoclonal antibody-based imaging agent for immuno-PET. The purpose of this study was to quantitatively evaluate the diagnostic ability of general trastuzumab and thio-trastuzumab as HER2 positive receptors based on Df hexadentate iron chelator. Desferrioxamine-p-SCN (Df-Bz-NCS) and desferroixamine-maleimide (Df-Mal) were purchased from Macrocyclics (Dallas, TX, USA). The trastuzumab was purchased from Roche (Schweiz), and thio-trastuzumab was obtained from professor Hyo-Jeong Hong group (Kangwon National University). The radioisotope ⁸⁹Zr was produced by domestic purification system and KIRAMS using medical cyclotron (50 MeV, Scantronix). The conjugates of Df-trastuzumab and Df-thio-trastuzumab were prepared with Df-Bz-NCS and Df-Mal under basic aqueous solution (pH 8-9) at room temperature, respectively. The conjugates purified by PD-10 column were mixed with dried ⁸⁹Zr chloride. ⁸⁹Zr-labeled conjugates were purified and concentrated by Amicon ultra centrifugal filter. The preparation step and time of ⁸⁹Zr-labeled conjugates was shorted as 4 steps within 2 hours. ⁸⁹Zr-labeled conjugates showed the highly radiochemical purity of over 98%, and were very stable until 7 days by the analysis of radio-ITLC method. Each radio-labeled conjugates were also exhibited the highly stability in both PBS buffer and mouse serum. Immuno-PET imaging of ⁸⁹Zr-labeled conjugates in mice bearing gastric cancer xenograft tumors with HER2 expression showed high tumor uptake in the NCI-N87 HER2-expressing. However, ⁸⁹Zr-Df-Mal-thio-trastuzumab showed a relatively lower tumor-to-background ratio than ⁸⁹Zr-Df-Bz-trastuzumab, as well as whole-body distribution. In the results, ⁸⁹Zr-Df-Bz-trastuzumab was evaluated to have a relatively higher HER2 diagnostic ability than ⁸⁹Zr-Df-Mal-thio-trastuzumab.

• International conference on construction engineering and project management
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1352-1358
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• 2009

As the demand for a convergence between construction technologies and IT is on the rise, as seen in the visualization of U-City construction, studies on the ways in which IT in should be utilized in the building and construction field have been continuously and actively performed. However, there has been almost no development of standardized technology criteria relating to the life cycle of a building (planning, design, construction, and maintenance). That is, there are almost no examples of efforts made to combine construction technology and IT in a fundamental way, considering the environment, the facility, its spatial characteristics, engineering, materials, and structure, aspects that are commonly required not only for interior spaces but also for exterior construction of U-City. Despite the fact that a state-of-the-art infrastructure has been built, and the competency of users with the cutting-edge technology, composite studies on technologies, facilities, services and spaces are still lacking, and basic research on the composite operation method including compatibility and linkage between facilities and services within a U-City has been insufficient as well. It is generally known that by fusing IT with construction technologies, the total period of construction taken can be reduced and construction expenses can be curtailed, while construction quality can be improved. For this reason, it is vital to prepare a standardized base to connect cutting-edge IT with the construction technologies. In preparing such a base, the most urgent issue is to develop standardized technology criteria. The ultimate objective of this research is to establish the technological criteria system required to apply construction-IT fused technologies to U-Cities, and to develop the technological criteria for the design, construction and maintenance of the U-Cities. This paper, whose objective is to establish development strategies for construction-IT fused technologies by way of analyzing the criteria for conventional construction projects, the necessity of criteria for construction-IT fused technologies, and the current status of U-Cities' development, is the underlying research for this purpose. The strategies established are expected to be utilized in establishing the system of criteria for construction-IT fused technologies, and to contribute to a knowledge base in the construction-IT field. In addition, based on the strategies established, criteria for construction-IT fused technologies, such as design criteria and construction standards, will be developed, and by applying these criteria and standards, the ultimate objectives of U-Cities, which are the enhancement of urban competitiveness and the satisfaction of residents, will be attained