• Journal of the Korean Wood Science and Technology
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• 제43권3호
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• pp.327-333
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• 2015

진공가압 수지함침 처리에 의한 목재의 치수안정화 정도를 측정하기 위하여 침엽수 3수종에 수용성 멜라민 수지를 수지농도와 처리시간별로 처리한 후, 수지함침 열압축목재(compreg)를 제조한 다음 치수안정성 개선효과를 검토하였다. 수지농도가 높고 처리시간이 길수록 용적 수축률과 항용적 팽윤율은 증가하였으나, 용적 팽윤율, 항용적 수축률 및 흡수성은 감소하였다. 또한 중량 증가율은 수지의 농도가 높을수록 현저히 증가하였으나 처리시간과는 일정한 관계가 없었다.

• Journal of the Korean Wood Science and Technology
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• 제48권5호
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• pp.722-731
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• 2020

The purpose of this research is to determine the efficiency of impregnation using phenol formaldehyde resin to enhance Falcataria wood's stability and better mechanical properties. Impregnation process was carried out after moisture content stabilized at 12% on samples with a dimension of 20 mm × 20 mm × 300 mm at various concentrations and pressure time. Dimensional stability was evaluated by thickness swelling (TS) and anti-swelling efficiency (ASE) and the young's modulus was conducted according to BS 573. The mechanical properties and dimensional stability of impregnated wood were evaluated. Dimensional stability and mechanical properties of Falcataria wood were successfully increased after impregnation. PF impregnation can improve the mechanical properties and the density from 0.26 g/㎤ to 0.30 g/㎤ even with only 10% of weight percent grain. Dimensional stability increases with increasing resin concentration and time pressure. The highest increase in mechanical properties was found at a higher concentration of PF. The penetration of PF into the wood's cell darkens the color of impregnated wood.

• Journal of Forest and Environmental Science
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• 제29권2호
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• pp.109-115
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• 2013

Fast-grown wood generally contains a high proportion of juvenile wood that results in inferior dimensional stability and durability against biological deteriorations. In the present research, the Acacia mangium wood from plantation forests in Vietnam was treated with high temperature in air. The effects of heat treatment on physical properties of Acacia mangium wood, including mass loss (ML), water absorption (WA), water-repellent effectiveness (WRE) and anti-swelling efficiency (ASE) were examined. The results showed that the dimensional stability and the water-repellent effectiveness are increased by about 15-46% and 8-18%, respectively. However, the mass and dimension of wood are decreased. The results also indicated that both treatment temperature and treatment duration significantly affect the wood properties of Acacia mangium. It is thus concluded that heat treatment demonstrates an interesting potential to improve the wood quality of Acacia mangium for solid timber products. This technology provides an environmentally safe method of protecting sustainable common woods to give a new generation of value-added biomaterials with increased stability without the use of toxic chemicals.

• Journal of the Korean Wood Science and Technology
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• 제51권2호
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• pp.133-144
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• 2023

Densification is an effective method for improving the physical and mechanical properties of low-density wood. However, the set-recovery of dimensions was found to be the problem of densified wood due to low fixation during the densification process. Alkali pretreatment before densification is thought to be a modification process to improve the dimensional stability of densified wood. In this research, the wood samples used were boiled in a 1.25 N sodium hydroxide (NaOH) solution at different times, followed by densification for 5 h at 100℃. The alkali pretreatment for 1, 3, and 5 h of boiling increased the dimensional stability of densified woods and anti-swelling efficiency values were 8.52%, 63.24%, and 48.94%, respectively. The boiling of wood in NaOH solution decreased the holocellulose content, as well as lignin to a lesser degree, and a lower crystallinity index was observed. The lower hydroxyl groups and a higher proportion of lignin in treated samples seem to have contributed to the high dimensional stability detected.

• 대한화장품학회:학술대회논문집
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• 대한화장품학회 2003년도 IFSCC Conference Proceeding Book I
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• pp.617-629
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• 2003

A recent development in cosmetics has been the pursuit of wrinkling in the skin. The cosmetics composed of anti-wrinkle agent stand out from the point of view of environmental contamination and pollution. Among them, Indole-3-acetic acid (IAA), studied with wrinkling pigmentation and swelling conditions in the area of the eye, showed clinically significant reduction in depth of lines during one month trial using skin treatment. But, IAA has shown some problems when used in cosmetic formulations, such as stability, permeability and toxicity. The results of the clinical examination were shown that its permeability and toxicity didn't matter. To increase the stability of IAA, antioxidants such as Licorice, ubiquinone, tocopherol, Baicalin, ferulic acid, BHT, ascorbic acid, sodium metabisulfite, and so on were employed in cosmetic formulations. Our main purpose is the study for the stability efficiency and effect of each other of cream formulations containing optimal dosage antioxidants (o/w type emulsion), This study evaluated wrinkle reduction effect of IAA, which is used in cosmetics.

• 농업과학연구
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• 제36권1호
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• pp.19-25
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• 2009

This study was carried for recycling laminated PB and MDF of disused furniture. PB and MDF particles taken from disused furniture were heat-treated at $250^{\circ}C$ and four levels of treatment time, 2, 4, 6 and 8 hours. The recycled boards were made with heat-treated particles after milling and screening with 100 mesh. The bending strength of the recycled boards were lower than that of virgin boards while their anti-swelling efficiency were much improved. Their formaldehyde emissivity were very low. Thus it was concluded that the recylcled boards are prospective environment-friendly material for interial consturction.

• 방사선산업학회지
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• 제9권4호
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• pp.199-207
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• 2015

Typical radiation cross-linked hydrogels has the characteristic that high water content, but low emission efficiency of active ingredients. Therefore, the hydrogel was prepared by the addition to collagen, which is closely related to the formation of skin wrinkles in biocompatibility and highly water-soluble carboxymethyl cellulose sodium salt (CMC) in order to preparation of hydrogels has excellent emission efficiency of active ingredients. Hydrogels were prepared by dissolving CMC and collagen each of 0.5%, 10% concentration in deionized water. Then, prepared hydrogels are performed by gamma-radiation at 1, 3, 5 kGy irradiation dose. The results showed that the gel fraction of after irradiated 3 kGy hydrogel was higher than before irradiated gelation as long as the 55.3%. The swelling rate of irradiated 3 kGy hydrogel was lower than the non-irradiated sample. The compressive strength of 3 kGy irradiated hydrogel was the highest. The visco-elastic did not show any significant differences, even after irradiation. The CMC hydrogel in this study suggested a potential use as a material for the mask pack for improved emission efficiency of the active ingredient and anti-wrinkles.

• 대한의생명과학회지
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• 제18권2호
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• pp.175-179
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• 2012

It is desirable that a wound healing membrane acts as a barrier for coverage of a damaged skin and has the biological activities such as anti-inflammatory effects. In this study, we prepared the hydrogel film containing the propolis nanoparticles as a wound healing membrane. The propolis nanoparticles were prepared by incorporation of propolis into the hydrophobic core of ${\gamma}$-cyclodextrin. The incorporation efficiency of propolis in the nanoparticles was $50{\pm}2.3%$. Propolis nanoparticles observed by a scanning electron microscope (SEM) were spherical with the size of 30~40 nm. The swelling behaviors of the hydrogel film containing propolis nanoparticles showed a similar pattern with the hydrogel film without propolis nanoparticles. The cumulative amount of propolis released from the hydrogel film containing propolis nanoparticles in the buffer of pH 7.4 and 5.5 was $86.0{\pm}2.0%$ and $64.6{\pm}1.0%$ of total propolis loaded in the hydrogel film within 9 h, respectively. These results provide a rationale for studying wound healing application of the hydrogel film containing propolis nanoparticles in a clinical setting.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.49-54
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• 2014

Background: Hydrogels are a class of polymers that can absorb water or biological fluids and swell to several times their dry volume, dependent on changes in the external environment. In recent years, hydrogels and hydrogel nanocomposites have found a variety of biomedical applications, including drug delivery and cancer treatment. The incorporation of nanoparticulates into a hydrogel matrix can result in unique material characteristics such as enhanced mechanical properties, swelling response, and capability of remote controlled actuation. Materials and Methods: In this work, synthesis of hydrogel nanocomposites containing magnetic nanoparticles are studied. At first, magnetic nanoparticles ($Fe_3O_4$) with an average size 10 nm were prepared. At second approach, thermo and pH-sensitive poly (N-isopropylacrylamide -co-methacrylic acid-co-vinyl pyrrolidone) (NIPAAm-MAA-VP) were prepared. Swelling behavior of co-polymer was studied in buffer solutions with different pH values (pH=5.8, pH=7.4) at $37^{\circ}C$. Magnetic iron oxide nanoparticles ($Fe_3O_4$) and doxorubicin were incorporated into copolymer and drug loading was studied. The release of drug, carried out at different pH and temperatures. Finally, chemical composition, magnetic properties and morphology of doxorubicin-loaded magnetic hydrogel nanocomposites were analyzed by FT- IR, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM). Results: The results indicated that drug loading efficiency was increased by increasing the drug ratio to polymer. Doxorubicin was released more at $40^{\circ}C$ and in acidic pH compared to that $37^{\circ}C$ and basic pH. Conclusions: This study suggested that the poly (NIPAAm-MAA-VP) magnetic hydrogel nanocomposite could be an effective carrier for targeting drug delivery systems of anti-cancer drugs due to its temperature sensitive properties.

• Journal of the Korean Wood Science and Technology
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• 제42권1호
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• pp.13-19
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• 2014

국내의 주 생산 수종인 잣나무 $90{\times}90mm$ 각재의 적정한 열처리 조건을 찾기 위해 3가지 열처리 스케줄을 적용하여 재색과 물성에 미치는 영향을 연구하였다. 1차 열처리시 온도는 $170^{\circ}C$와 $190^{\circ}C$, 시간은 예비가열시간 1시간을 포함하여 9시간과 13시간을 적용하였다. 2차와 3차 열처리는 모든 공시 각재에 동일하게 $190^{\circ}C$-9시간을 적용하였다. 열처리 횟수가 증가할수록 백색도 $L^*$는 직선적으로 감소하였으며 표준편차도 감소하였다. 열처리 횟수가 증가할수록 색차 ${\Delta}E^*$는 직선적으로 증가하였으며, 표준편차가 커지는 경향이 있었다. 알려진 바와 달리 열처리 시편의 평균 종압축강도가 무처리 시편보다 9% 높았다. 항팽윤율과 중량증가율을 측정하여 열처리 시편의 치수안정성이 무처리보다 크게 증가하였음을 보였다.