• Journal of the Korean Wood Science and Technology
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• 제41권2호
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• pp.111-122
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• 2013

The steam explosion-chemical pretreatment is a more effective wood pretreatment technique than the conventional physical pretreatment by accelerating reactions during the pretreatment process. In this paper, two-stage pretreatment processes of hardwood were investigated for its enzymatic hydrolysis and the succinic acid yield from the pretreated solid. The first stage pretreatment was performed under conditions of low severity to optimize the amount of solid recovery. In the second stage pretreatment washed solid material from the first stage pretreatment step was impregnated again with chemical (alkaline or chlorine-based chemicals) to remove a portion of the lignin, and to make the cellulose more accessible to enzymatic attack. The effects of pretreatment were assessed by enzymatic hydrolysis and fermentation, after the two stage pretreatments. Maximum succinic acid yield (16.1 g $L^{-1}$ and 77.5%) was obtained when the two stage pretreatments were performed at steam explosion -3% KOH.

• 펄프종이기술
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• 제43권1호
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• pp.1-10
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• 2011

To investigate the combination dyeing properties of natural dyes, the combination dyeing using gallnut,-Al, Cu, Fe-sappan wood, and gallnut-Al, Cu, Fe-gardenia was performed on bast fiber of mulberry, cotton, silk, and their K/S values, colors, and sunlight fastness were measured. The gallnut-Al, Cu, Fe-gardenia dyeing showed the highest K/S values when the dyeing concentration of gallnut is 3%. It tended to show the higher K/S values than gallnut-Al, Cu, Fe-sappan wood. The silk showed the highest values of in K/S, and then followed by cotton, and bast fiber of mulberry. The mordants developed different colors on the bast fiber and the cotton treated with gallnut-Al, Cu, Fe-sappan wood. However, the silk showed a series of YR, showing no effect of the mordants on the development of color. The combination dyeing of gallnut-Al, Cu, Fe-gardenia showed a series of Y. The results showed that sappan wood could develop various colors but gardenia could develop a series of Y. No distinct improvement on sunlight fastness of the combination dyeing was observed.

• 펄프종이기술
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• 제43권1호
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• pp.57-64
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• 2011

The purpose of this research is to investigate the anatomical and chemical properties of arrowroots for the use of paper fibers. The cells consisting of arrowroots showed certain affinities with those in the fibers and vessels of hardwood. Its parenchyma cells showed different shapes with those of hardwood. It was observed that starch was filled in the multi-shape cells. The average width and length of arrowroot fibers were $15.2{\mu}m$ ($11.1-20.3{\mu}m$) and 1.9 mm (1.49 mm-2.31 mm), respectively. In the chemical characteristics of arrowroots, the contents of cold- and hot-water, alcohol-benzene, and alkali extractives were 12-17%, 15.6%, and 38.8%, respectively. Its chemical composition was 61.3% holocellulose, 15.5% lignin and 2.0% ash.

• 펄프종이기술
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• 제45권6호
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• pp.55-63
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• 2013

To offer a basic information for the fibers of commercial leaflets, authors examined and analyzed the distribution, size, and printing types of leaflets sandwiched in the newspaper. The number of different leaflet size were almost 30 in two years including B5 ($182{\times}257mm$), A4 ($210{\times}297mm$), B4, ($257{\times}364mm$), A3 ($297{\times}420mm$), and large flyers such as $545{\times}395mm$, and $790{\times}550mm$. The number of different leaflets size were 25 in 2011, which was reduced to 15 in 2012. Both the number and amount of the leaflets were reduced. The high quality leaflets were issued and distributed in the corporate sector and the leaflets issued in other sectors such as shopkeeping, restaurant business, educational institutions were one-sided leaflets printed on single side of the paper. Compared to the previous year, large stores showed the increased number of leaflets but the number of leaflets from restaurant business and educational institutions and building trade were decreased.

• 소성∙가공
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• 제29권6호
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• pp.323-330
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• 2020

The surface region of a sheet metal may have different characteristics from the inner region because the surface region is less restricted than the interior. In addition, the grains on the free surface are less hardened because of surface adsorption of the dislocations, rather than piling up. In the case of bulk or thick sheet metals, this effect is negligible because the fraction of the surface region is much smaller than that of the inner region. However, this surface effect is important in the case of ultra-thin sheet metals. In order to evaluate the surface effect, tensile and bending tests were performed for the SS304 stainless steel with a thickness of 0.39 mm. The bending force predicted using the tensile behavior is higher than the measurement because of the surface effect. To account for the surface effect, the surface layer model was developed by dividing the sheet section into surface and inner layers. The mechanical behaviors of the two regions were calibrated using the tensile and bending properties. The surface layer model reproduced the bending behavior of the ultra-thin sheet metal.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2009년도 춘계학술논문발표회 논문집
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• pp.557-563
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• 2009

FMVSS 302 수평 연소 시험법을 통과한 자동차 내장재의 열적 특성을 평가하기 위해서 콘칼로미터를 이용하여 시험을 수행하였다. 화재 위험과 관련된 착화시간(time to ignition), 열방출률(heat release rate), 질량감소율(specific mass loss rate), 감쇠계수(extinction coefficient) 그리고 연기요소(smoke factor)와 같은 여러 가지 요소들을 분석하였다. 최대 열방출률값은 시험편에 따라 232${\sim}$635kW/$m^2$으로 큰 편차를 보였으며, 연기요소 또한 99${\sim}$551MW/$m^2$로 큰 편차를 보였다. 보조매트의 최대 열방출률은 다른 시험편에 비해서 상대적으로 낮은 값을 보였지만, 총연기 발생이 다른 시험편에 비해서 상당히 높았다. 따라서 최대 열방출률과 총 연기발생을 함께 고려한 연기요소값은 상대적으로 다른 시험편에 비해서 높게 나타났다.

• 패션비즈니스
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• 제23권5호
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• pp.124-136
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• 2019

Capstone design is a creative and comprehensive educational program requiring practical adaptation skills for the industry. The purpose of this study was to analyze the results of design development, lectures and curriculum satisfaction for textile fashion products based on four years of capstone design curriculum from 2015 to 2018. The curriculum consists of 26 groups of 72 students and a total of 26 final results were obtained via industry-university cooperation. The materials for product design development included differentiated clothing, leisure goods, bags, dog goods, smart goods, interior goods and recycled products based on textiles. The degree of satisfaction with lectures involving the capstone design class was very high, with 4.2 out of 5.0 when the number of students was less than 10. However, when the number of students was 20 or higher and the number of students was large, the level of satisfaction was below 3.88. Therefore, the capstone design class comprising less than 10 students was better at individual teaching and teamwork. In terms of satisfaction with capstone design curriculum, the respondents indicated that the teaching method addressing the needs of industry and academia facilitated practical learning. It was very helpful in improving competency related to the design and development majors and future employment. The capstone design curriculum was effective in the training for practical design development and planning.

• Smart Structures and Systems
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• 제24권4호
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• pp.427-434
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• 2019

This study investigates the structural integrity of the amphibious tour bus under the rollover condition. The multi-purpose bus called Dual Mode Tour Bus (DMTB) which explores on land and water has been designed on top of a truck platform. Prior to the fabrication of new upper body and sailing equipment of DMTB, computational analysis investigates the rollover protection of the proposed structure including superstructure, wheels, and axles. The Computer-Aided Design (CAD) of the whole vehicle model is meshed and preprocessed under high performance using the Altair HyperMesh to attain the best mesh model suited for finite element analysis (FEA) on the proposed system. Meanwhile, the numerical model is analyzed by employing LS-DYNA to evaluate the superstructure strength. The numerical model includes detail information about the microstructure and considers wheels and axles as rigid bodies but excludes window glasses, seats, and interior parts. Based on the simulation analysis and proper modifications especially on the rear portion of the bus, the local stiffness significantly increased. The vehicle is rotated to the contact point on the ground based on the mathematical method presented in this study to save computational cost. The results show that the proposed method of rollover analysis is highly significant not only in bus rollover tests but in crashworthiness studies for other application. The critical impartments in our suggested dual-purpose bus accepted and passed "Economic Commission for Europe (ECE) R66".

• 소성∙가공
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• 제30권5호
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• pp.226-235
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• 2021

The strain aging behavior of a low carbon dual phase steel was examined in two conditions: representing room temperature strain aging (100 ℃ × 1 hr after 7.5 % prestrain) and bake hardening process (170 ℃ × 20 min after 2 % prestrain), basing on carbon effective diffusion and dislocation distribution. The first principle calculations revealed that (Mn or Cr)-vacancy-C complexes exhibit the strongest attractive interaction compared to other complexes, therefore, act as strong trapping sites for carbon. For room temperature strain aging condition, the carbon effective diffusion distance is smaller than the dislocation distance in the high dislocation density region near ferrite/martensite interfaces as well as ferrite interior considering the carbon trapping effect of the (Mn or Cr)-vacancy-C complexes, implying ineffective Cottrell atmosphere formation. Under bake hardening condition, the carbon effective diffusion distance is larger compared to the dislocation distance in both regions. Therefore, formation of the Cottrell atmosphere is relatively easy resulting in to a relatively large increase in yield strength under bake hardening condition.

• 한국표면공학회지
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• 제52권1호
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• pp.43-51
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• 2019

The environmental pollution which is global warming and abnormal climate is caused by increasing population and activated economics. To reduce environmental pollution, we have being efforts into reducing $CO_2$ emission and use of energy, resources. Especially, for the sake of light weight and fuel efficiency of automotive industry, many countries have defined the restrict environmental regulation which stipulate high magnitude of reducing $CO_2$ emission. In this study, we have predicted the problem of Mu-cell injection molding through the finite element analysis as a function of temperature controlled by Joule heating or in terms of mold temperature. From the result of finite element analysis, we have determined the optimized process and made the injection mold included electric current heating system with Mu-cell manufacturing. Lastly, we analyzed the surface characteristics of the injection products with mold temperature.