• Journal of the Korean Wood Science and Technology
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• v.44 no.6
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• pp.913-922
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• 2016

This study attempted to measure molecular weight (MW) of melamine-urea-formaldehyde (MUF) resins prepared by two different synthesis methods: the one-step MUF resins were synthesized in one batch procedure, while the two-step MUF resins were prepared by a physical mixing of urea-formaldehyde (UF) resin with melamine-formaldehyde (MF) resin that had been synthesized in a separate procedure. The properties of medium density fiberboard (MDF) panels bonded with two types of MUF resins were also investigated. MWs of these MUF resins were measured using gel permeation chromatography (GPC). In addition, this study measured the MWs of one-step MUF resin during its synthesis procedure. The performance of two types of MUF resins was evaluated by determining properties of MDF panels prepared in laboratory. As the synthesis procedure progressed, both number average MW ($M_n$) and weight average MW ($M_w$) of one-step MUF resin gradually increased, while the polydispersity index (PDI) decreased. And low Mw species of the resin predominantly decreased as the synthesis step progressed. The one-step MUF resin showed greater $M_n$ and $M_w$ than those of the two-step ones even though the PDI values of both resins were very similar each other. As expected, the one-step MUF resin resulted in better properties of MDF panels than those of two-step resins. In particular, the one-step MUF resin provided better internal bond (IB) strength and thickness swelling (TS) with MDF panels than those of two-step ones, indicating better water resistance of the one-step resin. These results suggest that the preparation method of MUF resins have a great impact on the MW and final panel properties.

• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.360-367
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• 2017

This study was carried out to compare the characteristics of low density fiberboards (LDFs) manufactured with different adhesive types such as melamine urea formaldehyde (MUF), phenol formalehyde (PF), emulsified MDI (eMDI) and latexes resins. As results, hard LDFs were successfully manufactured by MUF, PF and eMDI resins. Thermal conductivities of all LDFs were significantly lower than commercial medium density fiberboard. Especially, all LDFs showed comparable thermal insulation performance with extruded polystyrene foam (XPS). LDF manufactured with eMDI resins showed the highest physical properties such as thickness/length swelling by water absorption and bending strength.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.449-458
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• 2010

This study attempted to investigate the effect of panel thickness on the horizontal density distribution (HDD) of medium density fiberboard (MDF) in a destructive way. Full size MDF panels with five different thicknesses such as 2 mm, 4.5 mm, 9 mm, 18 mm and 30 mm were cut into two different specimen sizes, i.e., $500{\times}500\;mm$ and $120{\times}120\;mm$ to measure the HDD. In general, the overall density of MDF panel diminished as the thickness increased, showing the highest density for the thinnest MDF panels. The HDD variation was significant for the samples of smaller specimen size ($120{\times}120\;mm$). MDF panel thickness significantly influenced to the HDD, which increased as the thickness decreased. In addition, the thinner panels showed much wider range in the HDD than those of thicker panels. The coefficient of variation (COV) of HDD also followed a similar trend to the panel density as the thickness increased. In summary, MDF panel thickness had a significant impact on the HDD within a panel. The sample size also showed a considerable effect to the HDD of MDF panels.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.2
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• pp.17-23
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• 1999

Top-to-bottom compression strength of corrugated fiberboard boxes is partly dependent on the load-carrying ability of the central panel areas. The ability of these central areas to resist bending under load will increase the stacking strength of the box. The difference of box compression strengths, among boxes which are made with identical dimensions and fabricated with same components but different flute sizes, is primarily due to difference of the flexural stiffness of the box panels. Top-to-bottom compression strength of a box is accurately predicted by flexural stiffness measurements and the edge crush test of the combined boards. This study was rallied out to analyze the flexural stiffness, maximum bending force and maximum deflection for various corrugated fiber-boards by experimental investigation. There were significant differences between the machine direction (MD) and the cross-machine direction (CD) of corrugated fiberboards tested. It was about 50% in SW and DW, and $62%{\sim}74%$ in dual-medium corrugated fiberboards(e.g. DM, DMA and DMB), respectively. There were no significant differences of maximum deflection in machine direction among the tested fiberboards but, in cross direction, DM showed the highest value and followed by SW, DMA, DMB and DW in order. For the corrugated fiberboards tested, flexural stiffness in machine direction is about $29%{\sim}48%$ larger than cross direction, and difference of flexural stiffness between the two direction is the lowest in DMA and DMB.

• Journal of the Korean Wood Science and Technology
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• v.37 no.4
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• pp.293-299
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• 2009

In manufacturing the crack-free carbonized boards using fiberboards, shrinking ratio, weight loss and density variation of carbonized boards at each carbonization temperature were investigated. Fiberboards with thickness of 3, 4.5, 6, and 18 mm were carbonized while pressed with pressure plates at different temperature from $400^{\circ}C$ to $1,000^{\circ}C$ using a ordinary laboratory furnace. Either of crack or twist was not observed in fiberboards by adapting the pressing carbonization method. The ratios of shrinkage of length, width, and thickness were 10~25%, 12~25%, and 28~48%, respectively, and shrinkage ratio of thickness was higher than those of length and width with increasing the carbonization temperature. Weight loss tended to increase with increasing the carbonization temperature, but low correlation between weight loss in thickness of fiberboards and carbonization temperature was observed. Density of 3 mm carbonized hardboard had the highest value and it tended to increase with increasing the carbonization temperature.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.1
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• pp.51-56
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• 2013

From the time the product is manufactured until it is carried and ultimately used, the product is subjected to some form of handling and transportations. During this process, the product can be subjected to many potential hazards. One of them is the damage caused by shocks. In order to design a product-package system to protect the product, the peak acceleration or G force to the product that causes damage needs to be determined. When a corrugated fiberboard box loaded with products is dropped onto the ground, part of the energy acquired due to the action of the gravitational acceleration during the free fall is dissipated in the product and the package in various ways. The shock absorbing characteristics of the packaging cushion materials are presented as a family of cushion curves in which curves showing peak accelerations during impacts for a range of static loads are shown for several drop heights. The new method for determining the shock absorbing characteristics of cushioning materials for protective packaging has been described and demonstrated. It has been shown that cushion curves can be produced by combining the static compression and impact characteristics of the material. The dynamic factor was determined by the iterative least mean squares (ILMS) optimization technique in which the discrepancies between peak acceleration data predicted from the theoretical model and obtained from the impact tests are minimized. The approach enabled an efficient determination of cushion curves from a small number of experimental impact data.

• International Journal of Reliability and Applications
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• v.6 no.2
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• pp.79-85
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• 2005

We show how comparative mean residual life functions (MRL) can be used to give unique insights into strengths of materials data. Recall that Weibull's original reliability function was developed studying and fitting strengths for various materials. This creative comparing of MRL functions approach can be used for regular life data or any time to response data. We apply graphical MRL's to real data from tests of tensile strength of high quality engineered wood.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2013.04a
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• pp.105-106
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• 2013

본 연구에서는 현재 사용되고 있는 대표적인 목질계 건축 재료를 대상으로 소방방재청 고시에 근거한 $45^{\circ}$연소성 실험을 실시하여 대상 실험 재료들의 방염 성능을 비교 평가 하였다. 실험결과, 잔진시간은 일반합판에서 높게 나타났고, 잔염시간은 OSB보드(Oriented Strand Board)에서 높게 나타난 것으로 분석되었다. 탄화면적과 탄화길이는 OSB보드와 중질 섬유판 보드(Medium Denstity Fiberboard)에서 높게 측정 되었으며, 6종류의 실험 제품들 모두 탄화면적과 탄화길이에서 기준치를 만족 못하는 것으로 평가 되었다.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.1
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• pp.30-36
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• 2009

Cracking of scored or creased lines on boards is a serious problem in converting process of corrugated fiberboard. It is important to reduce the possibility of score crack in advance by controlling the related quality factors of linerboard. To find out the key properties affecting score crack, we carried out the correlation analysis between score crack and physical properties of linerboards. Score crack was evaluated by visual rating on surface crack after folding a linerboard using laboratory folding resistance tester. Thickness of linerboard was the most important factor to score crack. The critical limits of thickness and strain can be determined by correlation analysis for reducing the possibility of score crack.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.170-173
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• 2003

음향방출 신호를 이용하여 목재 섬유판(fiberboards)의 위치표정의 유용성 유무를 실험적으로 검증하였다 위치표정의 정확도를 향상하기 위해 신호처리 방법중의 하나인 웨이블릿 변환 디노이징 기법을 활용하여 저주파수인 대칭모드(굽힘파)를 활용하고, 고주파수인 비대칭모드(팽창파)를 제거하여 신호를 재구성함으로써 섬유관의 위치표정시 문턱값 통과방법을 사용할 때 발생하는 도달시간차를 최소화 할 수 있음을 확인하였다. 디노이징 기법을 활용한 섬유판의 위치 표정과 굽힘강도에 대한 사상총수를 기초로 하여 목재 구조물 및 문화재의 건전성을 평가 할 수 있을 것으로 기대된다.