• 한국태양에너지학회 논문집
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• 제28권4호
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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.

• 교육녹색환경연구
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• 제17권3호
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• pp.35-45
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• 2018

본 연구는 학생들의 교육 및 생활 전반에 중요한 영향을 끼칠 수 있는 교육환경 개선 관련 지표를 개발하기 위한 목적으로 수행되었다. 이를 위해 문헌분석을 통해 선행연구와 차별화된 본 연구의 구체적인 방향과 교육환경 개선 개념을 설정하였으며, 교육환경 개선 지표 설정 방향 및 교육환경 개선 분야와 요소를 설정하였다. 이를 토대로 2차에 걸친 전문가 델파이 조사를 실시하였으며, 그 결과 연면적 적정성, 일반교실 적정성, 다목적강당 적정성 등 양적 측면의 지표 43개, 내진성능 확보유무, 소방시설 노후도, 화장실 노후도, 마감재 노후도 등 질적 측면의 지표 34개, 에너지사용량, 사용자 만족도 등 운영 측면의 지표 11개 등 총 88개의 교육환경개선 지표를 최종 설정하였다.

• The Journal of Advanced Prosthodontics
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• 제11권3호
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• pp.162-168
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• 2019

PURPOSE. The aim of this study was to evaluate the effect of occlusal adjustments on the surface roughness of yttria-tetragonal zirconia polycrystal (Y-TZP) and wear of opposing artificial enamel. MATERIALS AND METHODS. Twenty-five Y-TZP slabs from each brand (Lava, 3M and Bruxzir, Glidewell Laboratories) with different surface conditions (Control polished - CPZ; Polished/ground - GRZ; Polished/ground/repolished - RPZ; Glazed - GZ; Porcelain-veneered - PVZ; n=5) were abraded (500,000 cycles, 80 N) against artificial enamel (6 mm diameter steatite). Y-TZP roughness (in ${\mu}m$) before and after chewing simulation (CS) and antagonist steatite volume loss (in $mm^3$) were evaluated using a contact surface profilometer. Y-TZP roughness was analyzed by three-way analysis of variance (ANOVA) and steatite wear by two-way ANOVA and Tukey Honest Difference (HSD) (P=.05). RESULTS. There was no effect of Y-TZP brand on surface roughness (P=.216) and steatite loss (P=.064). A significant interaction effect (P<.001) between surface condition and CS on Y-TZP roughness was observed. GZ specimens showed higher roughness after CS (before CS - $3.7{\pm}1.8{\mu}m$; after CS - $13.54{\pm}3.11{\mu}m$), with partial removal of the glaze layer. Indenters abraded against CPZ ($0.09{\pm}0.03mm^3$) were worn more than those abraded against PVZ ($0.02{\pm}0.01mm^3$) and GZ ($0.02{\pm}0.01mm^3$). Higher wear caused by direct abrasion against zirconia was confirmed by SEM. CONCLUSION. Polishing with an intraoral polishing system did not reduce the roughness of zirconia. Wear of the opposing artificial enamel was affected by the material on the surface rather than the finishing technique applied, indicating that polished zirconia is more deleterious to artificial enamel than are glazed and porcelain-veneered restorations.

• 한국재난정보학회 논문집
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• 제15권1호
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• pp.12-19
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• 2019

연구목적: 촛불화재는 매년 같은 유형으로 반복되어 사상자가 발생하고 있기에 화재조사결과를 바탕으로 주로 발생되는 형태를 재현실험을 통해 분석하여 동종의 화재를 줄이는데 목적이 있다. 연구방법: 촛불화재 분석을 위해 아크릴 재연실험, 포멕스(FOMEX) 아크릴 재연실험, 일반가연물 재연실험, 촛불의 자연소화 재연실험 등 4가지 방법으로 실시하였다. 연구결과: 주변에 가연물의 접촉이 없으면 지속적인 연소가 이루어지기가 힘들다는 것을 확인하였다. 결론: 촛불화재를 예방하기 위해서는 주변 안전확인이 무엇보다 중요하며 초 말단에 은박지와 같은 불연 재료로 마감 처리하는 등 안전규정을 도입하는 것도 하나의 방법이라고 생각한다.

• 한국염색가공학회지
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• 제33권3호
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• pp.153-160
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• 2021

In this study, composite materials were prepared by varying the content of glass fiber and bamboo fiber in PP/glass fiber/bamboo fiber. Experiments were conducted to confirm the mechanical properties(tensile, impact and burst strength) and volatile organic compound content of the bamboo fiber composite prepared under these conditions. An improvement in the main properties was observed at a fiber content of 30wt%. When the fiber fraction was increased above 30wt%, the mechanical properties tended to decrease due to the agglomeration of fibers at higher load fractions. In addition, the content of volatile organic compounds increased as the content of bamboo fibers increased, which is thought to be due to the volatile organic compounds generated during the manufacturing process of the composite material being present in the composite material without escaping from the pores of the bamboo fibers and volatilizing at a certain temperature. As a result of confirming the physical properties of the composite, it is considered that the optimal mixing condition is 30wt% of bamboo fiber for the composite produced by varying the amount of bamboo fiber composite. In the future, it is thought that follow-up experiments to confirm and improve the pre-treatment conditions for reducing the content of volatile organic compounds in the manufactured composite material are possible.

• 패션비즈니스
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• 제25권1호
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• pp.1-15
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• 2021

Consumption value has widened, not only in functional but also aesthetic aspects, and consumers have started to find products that are more individual and emotional. The pattern of natural motifs meets the needs of consumers, and the marble is also widely used in patterns as one of the natural motifs. In this study, we analyzed many fashion items and other products with marble patterns based on the elements of CMF design, which are important points in merchandise design. For research, data on marble and its patterns have been found in professional books about marble. Foreign and domestic cases were investigated from well-known design exhibitions. Results of the study demonstrate the potential for pattern representation that stimulates consumers' senses by using color or material to express a variety of visual patterns, and using many finishing methods to express textured patterns. However, most of the domestic cases have only imitated the visual features of marble patterns, and very few have expanded the scope of the use of the patterns. A domestic research study was conducted only on the chemical features of marble, while research on the color and design of the visual aspects has been conducted passively. Therefore, This study will attribute designers to come up with creative pattern design and secure many consumers. Above all, we hope that the expansion of material representations will help designers break away from today's stereotypes of the characteristics of the materials and emotional expression.

• 한국염색가공학회지
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• 제34권2호
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• pp.117-126
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• 2022

In this study, thermoplastic composites were manufactured using ABS(acrylonitrile butadiene styrene), PC(polycarbonate), and POE(polyolefin elastomer), which are thermoplastic plastics. Twin screw extruder and injection molding were used to manufacture thermoplastic composites. When the ABS/PC/POE thermoplastic composite material was manufactured, the POE mass fraction was set to 1 to 5 wt.%, and the thermal and mechanical properties according to the POE mass fraction were analyzed. Based on the physical properties of ABS/PC/POE, a 3D model in the form of an e-bike frame was created. After setting the boundary conditions, when an external load is applied, geometry simulation was performed to predict product performance. The ABS/PC/POE thermoplastic composite material exhibited the best physical properties when the mass fraction of POE was 3 wt.%. In the simulation results for the physical properties of the 3D model in the form of an e-bike frame, the best physical properties were shown when the mass fraction of POE was 2 ~ 3 wt.%. As a result, the manufacturing conditions for ABS/PC/POE thermoplastic composite materials were set, and research was conducted to reduce product development costs and development time.

• 한국염색가공학회지
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• 제34권3호
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• pp.135-145
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• 2022

In this study, the dyeability of 0.06-denier-per-filament (dpf) ultrafine sea-island-type nylon knitted fabric was investigated and compared with that of 1.0-dpf general nylon with respect to four types of dyes. In particular, leveling, milling, half-milling, and metal-complex dyes were compared at concentrations of 0.5%, 1.0%, 2.0%, 4.0%, and 8.0% on-weight-fabric (o.w.f). In each case, staining was performed at 100 ℃. The dyeabilities of the materials were compared in terms of the depth of color as defined by the ratio of the absorption coefficient (K) to the scattering coefficient (S). Results indicated generally low K/S values for both the 0.06-dpf ultrafine sea-island-type nylon and 1.0-dpf general nylon. In terms of the dye type, the milling and half-milling dyes exhibited K/S values of ≥20 for all colors of yellow, red, and blue for the 0.06-dpf ultrafine yarn sea-island-type nylon, which were superior to those of the other dye types. Hence, the milling and half-milling dyes are considered more suitable than the other dyes. Further, a comparison of dye fastness and compatibility revealed that the half-milling dye was the most suitable dye for the 0.06-dpf ultrafine sea-island-type nylon.

• 한국염색가공학회지
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• 제34권3호
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• pp.157-164
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• 2022

This study tried to analyze the heat resistance properties by blending epoxy and phenolic resin in a certain ratio, and to analyze the adhesive properties at the time of metal-polymer hetero-adhesion by applying Epoxy-phenolic resin between a silicon steel sheet and m-aramid sheet, the viscosity, adhesive peel strength, and adhesive cross section were measured using a rotational rheometer, a tensile tester(UTM), and a field emission scanning electron microscopy(FE-SEM). The thermal stability and heat resistance were confirmed by measuring the mass loss according to the temperature increase using Thermogravimetric analysis(TGA). After blending with epoxy and Phenolic resin(1:0.25 ratio) curing at 110℃ for 10 min, high adhesive strength was improved more than 40% compared to the adhesive strength using epoxy alone. When the space between the silicon steel sheet and m-aramid sheet, which is created during curing of the E-P blend, is cured with a slight weight, it is possible to control the empty space and improve adhesion.

• 대한치과기공학회지
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• 제44권3호
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• pp.67-75
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• 2022

Purpose: This study aimed to comparatively evaluate the stress distribution of bones surrounding the implant system to which both titanium and polyetheretherketone (PEEK) abutments are applied using a three-dimensional finite element analysis. Methods: The three-dimensional implant system was designed by the computer-aided design program (CATIA; Dassault Systemes). The discretization process for setting nodes and elements was conducted using the HyperMesh program (Altair), after finishing the design of each structure for the customized abutment implant system. The results of the stress analysis were drawn from the Abaqus program (Dassault Systèmes). This study applied 200 N of vertical load and 100 N of oblique load to the occlusal surface of a mandibular first molar. Results: Under external load application, the PEEK-modeled dental implant showed the highest von Mises stress (VMS). The lowest VMS was observed in the Ti-modeled abutment screws. In all groups, the VMS was observed in the crestal regions or necks of implants. Conclusion: The bones surrounding the implant system to which the PEEK abutment was applied, such as the cortical and trabecular bones, showed stress distribution similar to that of the titanium implant system. This finding suggests that the difference in the abutment materials had no effect on the stress distribution of the bones surrounding implants. However, the PEEK abutments require mechanical and physical properties improved for clinical application, and the clinical application is thought to be limited.