• Journal of the Korean Society for Nondestructive Testing
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• v.32 no.5
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• pp.585-596
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• 2012

PVDF(poly vinylidene fluoride) and P(VDF-TrFE)(poly vinylidene fluoride-tetrafluoroethylene) are the typical piezoelectric polymers with unique properties. Even they are inferior to conventional piezoelectric ceramics PZT in electromechanical conversion efficiency and interior loss, though they are superior in receiving sensitivity and frequency bandwidth. Their acoustic impedances are relatively close to water or biological tissue and it is easier to make thin film than other piezoelectric materials. Futhermore, the film is so flexible that it is easy to attach on a complex surface. Those properties are suitable for the ultrasound transducers which are useful for medical and biological application, so that various types of polymer transducers have been developed. In this paper, several important considerations for design and fabrication of piezoelectric polymer transducers were described and their effect on the transducer performance were demonstrated through the KLM model analysis. Then, it was briefly reviewed about the structures of the polymer transducers developed for obtaining images as well as the characteristics of the images in several important medical and biological application fields.

• Fire Science and Engineering
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• v.24 no.1
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• pp.40-45
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• 2010

Asymmetric Slimflor Beam had been unveiled with Thor beam (Hat beam) in Sweden since the late 1970s and had been developed by British Steen and SCI. In the major advanced countries in Europe after the early 1990s have interested in and developed this method, it has been concrened as the absence of hot-rolled section steel in the United Kingdom and welded of asymmetric section steel in Finland in the 2000s. It can be increase total floor area about 10%, save the interior and exterior materials, reduce the waste through reduction of the floor height. And it has more excellent fire resistance performance because less exposed than a regular composite steel beam in fire. This study is purpose that, a fire resistance performance of the Asymmetric Slimflor Beam in fire, it compared the temperature range with deflection of structure by fire behavior and load ratio of structure through change the shape of the steel cross-section in standard fire condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3800-3805
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• 2012

Infrared(IR) reflective black cool pigment and paint which is used for interior/exterior materials(IR reflectance >30%) to prevent heat island effect and to increase energy efficiency were studied. Cool pigment was synthesized using mixture of $Fe_2O_3$ and $Cr_2O_3$ with calcination from 900 to $1,200^{\circ}C$. Cool paint was prepared by formulation of cool pigment, acrylic resins, and other additives. Results showed that optimum color fixation of pigment obtained by mole ratio of Fe to Cr was 0.9 with calcination temperature at $1,000^{\circ}C$. The cool paint formulated by 20% pigment and 1.5% dispersive additive with $125{\mu}m$ thickness of coated layer showed optimum IR reflectance. Temperature difference on surface between cool paint and ordinary paint(STD) was $36.5^{\circ}C$ and IR reflectance(TSR) was 39.3% at wavelength from 700 to 2,500nm. And color change was not detected during 500hrs weathering test.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.54-60
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• 2016

Building information modeling (BIM) has the advantage of having been utilized for various scenarios through a single model. Although extracting 2D drawings from BIM is one of the advantages, there are many difficulties when utilized in practical work. Architectural detail drawings are an important factor for expressing interior finishing materials and complicated construction methods, as well as for cost estimations. However, creating detail drawings does not have a standard, and each design company establishes its own detail drawings, so it is hard to share or exchange information in the construction industry. Therefore, this study suggests a systemized method for making detail drawings, and explains how it can be utilized as back data for quantity take-off and construction expenses linked with BIM libraries.

• Resources Recycling
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• v.4 no.1
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• pp.4-11
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• 1995

The amounts of waste stone and stone powder sludge that occurred in the quarry and processing plant of s stone plates, have been increased with the development of stone industry. The manufactunng process of 따tificial s stone was studied to reduce the outlet of these wastes and utilIze them as raw materials for architecture, interior decoration and art work. In order to compare the properties of artiflcial stone with those of natural building-stone, the physi$\alpha$II properties of artificial stone such as specific gravity, absorption ratio, elastic wave velocity, compressive s strength, tensile strength, shore hardness, elasticity and Poission's ratio were measured. From the mesaured d data of physical properties, it was found that physical propertIes of artificial stone were controlled by homogeneous m mixing ratio of constituents, molding pressure, and amount of binder. Also, from the thermo-gravimetric analysis, it was found that artIfIcial stone manufactured had a good thermal stability up to $300^{\circ}C$. It was concluded that t the optimum conditions for manufacturing process of artificial stone were $200kg/\textrm{cm}^2$ of molding pressure, 12-15 w weight % of binder amounts.

• Journal of agriculture & life science
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• v.46 no.2
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• pp.49-61
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• 2012

This study was carried out to investigate the chemical composition and the inorganic constituents of the green tea at the 3 picking periods (Ujeon, Sejag, Jungjag) in Hadong. The results as follows ; The contents of chlorophyll, tannin, vitamin-c and total catechin were increased as picking periods increased but the contents of total nitrogen, total free amino acids, theanine and caffeine were decreased on the reverse. The inorganic constituents Mg, Ca and Mn were increased as picking periods getting late but the Na, K, B contents were decreased on the reverse. The contents of the total nitrogen, chlorophyll, total free amino acid, theanine, caffeine and total catechin and Na, Mg, Ca, B and Se were insignificant differences between Ujeon and Sejag.

• Journal of the Korean Solar Energy Society
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• v.28 no.4
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• pp.10-16
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• 2008

The fire resistance of thermal insulation and interior finishing materials is recently much emphasized after the fire accident at the Icheon Cold Store in January 2008. Three kinds of thermal insulation are used in buildings. They are Organic, Non-organic and cellulosic insulation. Organic insulation such as polystyrene foam board and urethane foam has high thermal resistance but it has no fire resistance. While non-organic insulation such as rockwool and glassfiber has high fire resistance, it has lower thermal resistance than organic insulation. Cellulose insulation is primarily manufactured from recycled newsprint or cardboard using shredders and fiberizers. Despite of its environmental friendliness and high thermal resistivity, its domestic use has not much increased because of the prejudice that paper can easily burn. However, the cellulose insulation as a product is about 80 wt.% cellulosic fiber and 20 wt.% chemicals, most of which are fire retardants such as boric acid and ammonium sulfate. It is required to secure its fire safety for more consumption as a building insulation in Korea. Therefore, this study investigates the fire resistance of Korean cellulose insulation according to the rate of fire retardant and finally presents the optimum rate of fire retardant in cellulose as building insulation. The fire safety test was conducted according to the ASTM C 1485-00. The test results indicate that above 18 wt% of fire retardant is necessary to secure the fire safety of cellulose insulation.

• Journal of the Korea Institute of Building Construction
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• v.18 no.6
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• pp.621-631
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• 2018

The repair and maintenance cost of domestic public rental housing is an issue of considerable interest and growing financial concern. This paper suggests a quantity-based model as an alternative method for predicting costs, instead of the conventional model which is based on actual cost data. Furthermore, this paper provides a forecast of the repair costs incurred each year during the multi family house's maintenance phase (40 years). The recently changed the long-term repair plan and quality-improved interior materials were considered into the research. In order to estimate the cost of maintenance work, 5 sample apartments were selected and analyzed. The repair and maintenance cost from the case studies was converted to cost per household and per floor area for general use. On the other hand, the net present value method was applied to reflect the effect of time. We expect that the results will help to establish expenditure plans that are more effective for public rental housing in the maintenance stage.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.289-303
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• 2019

This paper presents research on furniture making based on Hojangjul, which is an engraving technique that highlights the wooden patterns of traditional furniture. Somokbang, one of the 12 workshops in Tongyeong, has used Hojangjul as an engraving technique since Imjinwaeran. It was inherited by the late Cheon Sang-won, who was No. 59 of National Important Intangible Cultural Properties, and developed into Samhojang, Ohojang, Seongtoinoimun, Hotguinoimun, and Gyeopguinoimun. It was then spread to Masan, Ulsan, and Gwangyang via marine routes and further into the inland areas via land routes, developing in various patterns and forms. The present study investigated and examined the making techniques and characteristics of Hojangjul engraved in joinery furniture in Tongyeong, Masan, and Ulsan in the Gyeongsang region and Gwangyang and Dongbok in the Jeolla region, thus shedding new light on the traditional techniques that have been gradually disappearing and promoting the transmission, inheritance, and development of the traditional techniques.

• Journal of the Korean Institute of Educational Facilities
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• v.26 no.3
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• pp.15-23
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• 2019

This study aims to suggest a Biophilic classroom design of high school to obtain attention restoration for students. The learning space for youth in the modern society is composed of dry artificial structures. This space is considered to be a space that can not relieve stress caused by learning. "The Attention Restoration Theory" is divided into "Directed Attention" of humans, which is the cause of fatigue and stress, and "Involuntary Attention" as a solution to it. "Involuntary Attention" takes place in a rest state and helps the brain recover when exposed to nature. And the core of "Biophilic-Design Theory" is that humans can recover physical and mental conditions when exposed to nature. The purpose of this study is to apply "The Biophilic-Design Theory" that emphasizes the importance of exposure to nature to the educational space and plan the space where the 'Attention Restoration' can be achieved. The research method is as follows. First, we review previous studies related to "The Biophilic-Design Theory" and "The Attention Restoration Theory". Second, we analyze the application examples of "The Biophilic-Design Theory" and "The Attention Restoration Theory" in domestic and foreign educational spaces. Third, the concept of educational space is set up based on the elements derived from previous studies. Finally, we propose the planning direction of classroom design based on Biophilic-Design. The following conclusions were drawn. First, The creation of the education space to restore the learner's attention requires a visual space plan that utilizes natural elements such as natural light, artificial light, plants, and natural materials that can directly experience nature. Second, the direction in which students in the classroom can be "The Attention Restoration Theory" should consider the use of indirect natural elements that bring the surrounding natural landscape into the interior. This study will be used as the baseline data for the spatial design and planning of education facilities based on Biophilic-Design.