• Elastomers and Composites
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• 제59권2호
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• pp.64-72
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• 2024

As air pollution continues to increase owing to increasing traffic centered in urban areas, the tire industry is researching methods to reduce particulate matter. In this study, functionalized lithium butadiene rubber (F-LiBR) was applied to a natural rubber (NR)/butadiene rubber (BR) blend compound often used in truck bus radial (TBR) tire treads. The effect of the functional group that can react with carbon black (CB) in BR was investigated in terms of the dispersion of CB and the compound performance, including the generation of particulate matter. Compounds that were substituted with F-LiBR exhibited enhanced interaction with CB, resulting in excellent filler dispersion. Although F-LiBR exhibited lower crosslinking density and inferior abrasion resistance due to its high vinyl content, the compound with 30 phr of F-LiBR was advantageous in terms of its rolling resistance due to the excellent filler dispersion, which was also effective in reducing the amount of generated particulate matter (up to 56% reduction for PM_2.5, and 67% reduction for PM₁₀). The results confirmed the benefits of the introduction of functional groups into TBR tire tread compounds, which can aid in improving the fuel efficiency and reducing particulate matter generation.

• 한국세라믹학회지
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• 제46권5호
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• pp.441-446
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• 2009

Dense crack-free yttria film with 10 $\mu m$ thickness was prepared on aluminum by aerosol deposition. X-ray diffraction pattern on the film showed that it contained the same crystalline phase as the raw powder. Transmission electron microscopy revealed a nanostructured yttria film with grains smaller than 100 nm. Tensile adhesion strength between the film and aluminum substrate was 57.8 $\pm$ 6.3MPa. According to the etching test with $CF_4-O_2$ plasma, the etching rate of the yttria film was 1/100 that of quartz, 1/10 that of sintered alumina and comparable to that of sintered yttria.

• 한국육종학회지
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• 제41권3호
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• pp.288-291
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• 2009

"동해진미"는 중만생종이면서 쌀 품위가 좋고 밥맛이 양호하며 내병성이 양호한 품종으로 주요특성과 수량성을 요약하면 다음과 같다 1. 출수기는 평야지의 보통기 재배에서 8월 14일로 "화성벼"보다 2일 늦은 중만생종이다. 2. 주당수수와 수당립수는 "화성벼"보다 약간 많은 편이고 현미천립중은 22.4 g으로 "화성벼"보다 다소 가벼운 중립종이다. 3. 불시출수와 수발아가 안되는 편이고, 위조현상에 강하고 성숙기 엽노화가 느린 편이며 내냉성은 "화성벼"와 출수 지연일수는 비슷하나 임실률은 낮은 편이다. 4. 잎도열병은 중도이상의 저항성이며 도열병 내구저항성도 "화성벼"보다 강하다. 흰잎마름병($K_1{\sim}K_3$)과 줄무늬잎마름병에는 저항성이이나 오갈병 및 검은줄오갈병과 충해에는 약하다. 5. 심복백은 거의 없고 "화성벼"수준으로 맑고 투명하며 도정률, 완전미율이 높다. 아밀로스함량은 "화성벼"보다 조금 높고 단백질함량은 낮으며 밥맛은 양호하다. 6. "동해진미"의 쌀수량은 보통기 보비재배 6개소에서 평균 6.05 MT/ha로 "화성"보다 9% 증수되었으나, 이모작재배에서는 4.97 MT/ha, 만식재배에서는 5.13 MT/ha의 수량을 보였다.

• Journal of Microbiology and Biotechnology
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• 제34권4호
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• pp.871-879
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• 2024

Our group had isolated Bifidobacterium breve strain BS2-PB3 from human breast milk. In this study, we sequenced the whole genome of B. breve BS2-PB3, and with a focus on its safety profile, various probiotic characteristics (presence of antibiotic resistance genes, virulence factors, and mobile elements) were then determined through bioinformatic analyses. The antibiotic resistance profile of B. breve BS2-PB3 was also evaluated. The whole genome of B. breve BS2-PB3 consisted of 2,268,931 base pairs with a G-C content of 58.89% and 2,108 coding regions. The average nucleotide identity and whole-genome phylogenetic analyses supported the classification of B. breve BS2-PB3. According to our in silico assessment, B. breve BS2-PB3 possesses antioxidant and immunomodulation properties in addition to various genes related to the probiotic properties of heat, cold, and acid stress, bile tolerance, and adhesion. Antibiotic susceptibility was evaluated using the Kirby-Bauer disk-diffusion test, in which the minimum inhibitory concentrations for selected antibiotics were subsequently tested using the Epsilometer test. B. breve BS2-PB3 only exhibited selected resistance phenotypes, i.e., to mupirocin (minimum inhibitory concentration/MIC >1,024 ㎍/ml), sulfamethoxazole (MIC>1,024 ㎍/ml), and oxacillin (MIC >3 ㎍/ml). The resistance genes against those antibiotics, i.e., ileS, mupB, sul4, mecC and ramA, were detected within its genome as well. While no virulence factor was detected, four insertion sequences were identified within the genome but were located away from the identified antibiotic resistance genes. In conclusion, B. breve BS2-PB3 demonstrated a sufficient safety profile, making it a promising candidate for further development as a potential functional food.

• 한국육종학회지
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• 제41권4호
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• pp.547-551
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• 2009

"칠보"는 국립식량과학원 영덕출장소에서 2007년에 육성한 쌀 품위가 좋고 밥맛이 양호하며 바이러스병에 강한 중만생 벼 품종으로 주요 특성과 수량성을 요약하면 다음과 같다. 1. 출수기는 평야지의 보통기 재배에서 8월 15일로 "화성벼"보다 3일 늦은 중만생종이다. 2. 주당수수는 18개로 "화성벼"보다 3개 많으며 수당립수는 적은 편이고 등숙비율은 더 높으며 현미천립중은 비슷한 중립종이다. 3. 심복백이 거의 없고 "화성벼"보다 맑고 투명하며 도정률 및 완전미율이 높고 아밀로스 및 단백질함량은 비슷하며 밥맛은 "화성벼"보다 양호하다. 4. 불시출수와 수발아가 않되는 편이고, 위조현상에 강하고 성숙기 엽노화가 느린 편이며 내냉성은 "화성벼"보다 출수지연은 심하고 임실률은 중정도이다. 5. 잎도열병은 중도저항성이며, 줄무늬잎마름병에는 강하나 흰잎마름병, 오갈병 및 검은줄오갈병에는 약하고 벼멸구 등 충해에는 감수성이다. 6. 쌀수량은 5.57 MT/ha로 "화성벼"보다 8% 증수 되었으며, 이모작재배에서는 5.33 MT/ha, 만식재배에서는 4.60 MT/ha의 수량성을 보였다.

• 한국도로학회논문집
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• 제14권5호
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• pp.67-74
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• 2012

PURPOSES: In this study the influence factors related to abrasion resistance of interlocking concrete block have been evaluated, and comparisons between various domestic and foreign abrasion test methods was also accomplished. METHODS: The modified rotational cutting method suggested in ASTM C 944 was applied. Surface materials with different types of fine aggregate such as crushed sand, sea sand, and mixture of crushed and sea sand were tested to compare the aggregate effect for abrasion resistance. RESULTS: The different surface mixtures with various W/C ratios, mortar and fly ash ratios have been investigated for functional and economical considerations. CONCLUSIONS: This study had obtained reliable results by changing diamond blade of rotating cutter. Therefore, in order to improve the abrasion resistance of interlocking concrete block for road, a new mix design was proposed.

• Journal of Magnetics
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• 제16권2호
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• pp.140-144
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• 2011

We report on a numerical calculation study of two new functional properties in magnetic tunnel junctions (MTJs), negative dynamic resistance and RF amplification. The magnetic dynamics in a conventional CoFeB/MgO/CoFeB MTJ with in-plane magnetization was investigated using a macro-spin model simulation. To examine the influence of thermal fluctuations, random external magnetic fields were also included. Using a voltage controlled bias circuit, the negative dynamic resistance was obtained from time averaged I-V characteristics at both 0 K and 300 K under appropriate external magnetic fields and bias voltages. Using this negative dynamic resistance property, we demonstrated RF amplification with a 100 MHz high frequency signal. Sizable RF amplification gain was observed without thermal fluctuation. However, at 300 K, the RF signal was not amplified because low frequency magnetization dynamics were dominant.

• Journal of the Korean Wood Science and Technology
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• 제32권6호
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• pp.23-35
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• 2004

The goal of study was to investigate the influence of the acrylated urethane oligomer on mechanical properties, the chemical resistance and thermal resistance of the UV curable urethane acrylate coatings for fancy veneer overlayed plywood flooring. The pencil hardness and abrasion resistance of the coated fancy veneer overlayed plywood floorings increased with increasing the acrylate functionality of the acrylated urethane oligomer. In the case of the UV cured film containing hexa-functional acrylated aliphatic urethane oligomer, high discoloration of the coated fancy veneer overlayed plywood flooring was observed near the cracks at the beginning of the chemical treatment. In this study, it was found that the degradation of the UV cured film caused by an alkaline reagent was higher than that of the UV cured film caused by an acidic treatment.

• The Journal of Korean Physical Therapy
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• 제35권5호
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• pp.132-138
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• 2023

Purpose: This study compared the effects of the elastic resistance and general training for college Taekwondo athletes, and investigated the biomechanical ability and lower extremity function according to the movement speed of the knee joint. Methods: Twenty university student Taekwondo athletes participated voluntarily in this study. The subjects performed general resistance training for four weeks, followed by elastic resistance training for another four weeks. The biomechanical parameters during the fast and slow isokinetic conditions, Y-balance ability, and vertical jump ability were measured three times: before training, after general resistance training, and after elastic resistance training. Statistical analysis was performed under isokinetic conditions and the intervention effect. Results: The biomechanical ability differed significantly between fast and slow isokinetic conditions (p<0.05). An analysis of the training method revealed a significant difference in the maximum knee extension speed and the posterior-lateral direction of the Y-balance test (p<0.05). Conclusion: Elastic resistance training had a more positive effect on the functional task performance than biomechanical factors related to muscular strength compared to general resistance training. In addition, speed-related knee biomechanical information of subjects with strong physical abilities could be utilized in sports physiotherapy.

• Food Science and Biotechnology
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• 제16권5호
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• pp.691-709
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• 2007

Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. However, inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance are causing a major limitation for their industrial use. By the way, recent advent of nanocomposite technology rekindled interests on the use of natural biopolymers in the food packaging application. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased mechanical strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have huge potential for application in the active food packaging industry. In this review, recent advances in the preparation and characterization of natural biopolymer-based nanocomposite films, and their potential use in food packaging applications are addressed.