• 원예과학기술지
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• 제19권4호
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• pp.550-554
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• 2001

관행적인 MA 저장보다 생리적 장해를 최소화시킬 수 있는 방법을 구명하고자 0.06mm의 PE film 밀봉 시 $O_2$와 $CO_2$의 조성을 각각 0% $O_2$+5% $CO_2$, 2% $O_2$+5% $CO_2$, 2% $O_2$+8% $CO_2$, 5% $O_2$+5% $CO_2$, 5% $O_2$+10% $CO_2$, 진공 및 대조구(air)를 두어 실험하였다. 봉지 내 $CO_2$ 농도는 처리 40일째 2% $O_2$+8% $CO_2$가 가장 높고, 0% $O_2$+5% $CO_2$가 가장 낮았으나 그 이후 처리 간 차이 없이 비슷하게 유지되었다. 감모율, 색도에는 2% $O_2$+8% $CO_2$ 처리구와 진공 처리구가, 경도, 당도, 시장성에는 2% $O_2$+5% $CO_2$ 처리구와 진공처리가 효과적이었다. 저장 중 봉지 내 과실이 심하게 밀착되면 접촉 부분의 연화과 발생이 증가되는 현상을 제외하고는 모든 조사항목에서 진공처리한 과실이 저장성이 가장 좋은 것으로 판단되었다.

• 한국포장학회지
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• 제19권2호
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• pp.61-65
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• 2013

Modified atmosphere (MA) of reduced $O_2$ and elevated $CO_2$ concentrations has been used for keeping the quality of fresh produce and extending the shelf life. As a way to attain the beneficial MA package around the produce, a gas diffusion tube or perforation can be attached onto the container and controlled on real time in its opening/closing responding to $O_2$ and $CO_2$ concentrations measured by gas sensors. The timely-controlled opening of the gas diffusion tube can work in harmony with the produce respiration and help to create the desired MA. By use of the mathematical modeling, the effect of tube dimension on the controlled container atmosphere was figured out in this study. Spinach and king oyster mushroom were used as typical commodities for designing the model container system (0.35 and 0.9 kg in 13 L, respectively) because of their respiration characteristics and the optimal MA condition ($O_2$ 7~10%/$CO_2$ 5~10% for spinach; $O_2$ 2~5%/$CO_2$ 10~15% for mushroom). With a control logic for the gas composition to stay as close as possible to optimum MA window without invading injurious low $O_2$ and/or high $CO_2$ concentrations, the atmosphere of the sensor-controlled container could stay at its lower $O_2$ boundary or upper $CO_2$ limit under certain tube dimensional conditions. There were found to be the ranges of the tube diameter and length allowing the beneficial MA. The desired range of the tube dimension for spinach consisted of combinations of larger diameter and shorter length in the window of 0.3~2 cm diameter and 0.2~10 cm length. Similarly, that for king oyster mushroom was combinations of larger diameter and shorter length in the window of 0.9~2 cm diameter and 0.2~3 cm in length. Clear picture on generally affordable tube dimension range may be formulated by further study on a wide variety of commodity and pack conditions.

• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3297-3300
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• 2010

In this study, the 3D-QSARs (three-dimensional quantitative structure-activity relationships: CoMFA and CoMSIA) between structural changes of N-phenyl-O-phenylthionocarbamate analogues (1-30) and their fungicidal activities against the capsicum phytophthora (Phyophthora capsici) fungi were analyzed, then considered quantitatively in terms of minimum structural requirements for fungicidal evaluation. The statistical qualities ($r^2_{cv.}$ = 0.510 and $r^2_{ncv.}$ = 0.948) of the optimal CoMFA 1 model are improved over the other models in the conditions of field combinations, and the two alignments. In the optimal CoMFA 1 model, relative contribution percentages of the CoMFA field were: steric field, 52.3%; electrostatic field, 37.8%; hydrophobic field, 9.9%. Results were similar for the CoMFA 2 model. Therefore, the steric field of the analogues had the highest contribution ratio for fungicidal activity. Specifically, with the contour map of steric fields, the fungicidal activity increased when bulky steric Y-substituents were introduced to the meta-position on the N-phenyl ring and small steric Y-subsituents were introduced to its para-position.

• 한국식품과학회지
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• 제30권4호
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• pp.871-876
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• 1998

"여봉" 딸기에 적합한 CA조건을 구명하기 위하여 $O_2$ (3,8%)와 $CO_2$ (10, 15, 20%)를 각각 조합한 CA저장 및 대조구인 저온저장중의 딸기 품질변화를 비교하였다. 호흡량은 증가하다가 감소하였으며 $O_2$ 3, 8% 모두 $CO_2$ 15%인 조건에서 적게 나타났고 에틸렌은 저온 저장에서는 계속 증가하였으며 CA저장은 $CO_2$ 20%에서 높게 나타났다. 부패과율은 저온저장 12일에 11.7%가 발생하였으나, $O_2{\;}3%+{\;}CO_2{\;}15%$의 CA저장에서는 28일에 11.7%로 가장 억제되었으며, 경도는 CA저장시 $CO_2$ 10% 및 15%에서는 24일, 20%에서는 16일 까지 비교적 유지되었다. 비타민 C는 저장중에 계속 감소하였으며 $O_2$ 3,8% 모두 $CO_2$ 15%인 조건에서는 저장 24일 까지 약 80% 유지하여 가장 높게 나타났다. 안토시아닌은 $O_2$ 3, 8%모두 $CO_2$ 20%인 조건에서 빠르게 증가한 다음 감소하였으나 $CO_2$ 10% 및 15%인 조건에서는 완만하게 변화하였다. 저장중 Hunter color의 a값은 전체적으로 높아지다가 감소하였으며 저온저장에서 가장 빨리 높은 값에 이르렀고 CA저장에서는 차이가 없었다. 또한 딸기의 이취발생 정도는 $CO_2$농도 20%에서 가장 심하여 저장 16일 후 관능적 수용이 어려웠고, $CO_2$10% 및 15%간에는 관능적으로 이취를 느끼는 차이가 없었으나 $O_2{\;}8%+{\;}CO_2{\;}15%$조건에서 가장 적은 이취발생을 나타내어 저장 24일까지는 품질이 유지되었다. 그리고 이때의 에탄올 함량은 $CO_2$ 농도가 높을수록 높게 나타났으나 $O_2$ 8%에서는 $CO_2$ 10%와 15%간에 차이가 적었다. 이상의 결과로 이취발생 및 에탄올 함량을 제외하고는 $O_2{\;}3%+{\;}CO_2{\;}15%$인 CA조건이 딸기의 선도유지에 가장 뛰어났지만 생식용 딸기에 있어서 이취가 품질에 미치는 영향이 매우 큰 점을 고려할 때 $O_2{\;}8%+{\;}CO_2{\;}15%$ 조건이 보다 적합하였다.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.11-11
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• 2000

Large-size ceramic/metal bulk FGMs have been fabricated on a recently developed and the world's largest Spark Plasma Sintering(SPS) systems, As a part of the development program for practical production processes and machines for FGMs by SPS, the processes, mechanical properties, dimensional size and shape effects, and production machine systems were investigated. In the past, $ZrO_{2}$/TiAI, $ZrO_{2}$/Ni, $Al_{2}O_{3}$/Ti, WC/Co, WC/Co/Steel, A1/P, Polymide, Cu/Polymide, nano-composites, porous and other combinations of bulk FGMs have already been processed using SPS. However, most of the specimen sizes were small, in a range of 20 to 30mm in diameter. Recently disk-shape sintered compacts with diameters of 100 and 150 mm, and thickness of approximately 15 and 17 mm, $ZrO_{2}$(3Y)/ stainless steel FGMs were homogenous consolidated in a shorter sintering time, while maintaining high quality and repeatability by utilizing a temperature gradient sintering method. The SPS heating up and holding time totaled less than one hour. Therefore, the SPS process in expected to find increased use in the fabrication of large-size FGMs as a new industrial processing technology. This paper introduces SPS systems, the processing principles, features and the characteristies of ceramic/metal bulk FGM.

• Journal of Microbiology and Biotechnology
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• 제17권6호
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• pp.960-967
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• 2007

The co-immobilization of Aspergillus niger glucose oxidase (GOD) with bovine liver catalase (CAT) onto florisil (magnesium silicate-based porous carrier) was investigated to improve the catalytic efficiency of GOD against $H_2O2$ inactivation. The effect of the amount of bound CAT on the GOD activity was also studied for 12 different initial combinations of GOD and CAT, using simultaneous and sequential coupling. The sequentially co-immobilized GOD-CAT showed a higher efficiency than the simultaneously co-immobilized GOD-CAT in terms of the GOD activity and economic costs. The highest activity was shown by the sequentially co-immobilized GOD-CAT when the initial amounts of GOD and CAT were 10 mg and 5 mg per gram of carrier. The optimum pH, buffer concentration, and temperature for GOD activity for the same co-immobilized GOD-CAT sample were then determined as pH 6.5, 50 mM, and $30^{\circ}C$, respectively. When compared with the individually immobilized GOD, the catalytic activity of the co-immobilized GOD-CAT was 70% higher, plus the reusability was more than two-fold. The storage stability of the co-immobilized GOD-CAT was also found to be higher than that of the free form at both $5^{\circ}C\;and\;25^{\circ}C$. The increased GOD activity and reusability resulting from the co-immobilization process may have been due to CAT protecting GOD from inactivation by $H_2O2$ and supplying additional $O_2$ to the reaction system.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.217-217
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• 2011

Recently, demand for thermally stable metal nanoparticles suitable for chemical reactions at high temperatures has increased to the point to require a solution to nanoparticle coalescence. Thermal stability of metal nanoparticles can be achieved by adopting core-shell models and encapsulating supported metal nanoparticles with mesoporous oxides [1,2]. However, to understand the role of metal-support interactions on catalytic activity and for surface analysis of complex structures, we developed a novel catalyst design by coating an ultra-thin layer of titania on Pt supported silica ($SiO_2/Pt@TiO_2$). This structure provides higher metal dispersion (~52% Pt/silica), high thermal stability (~600$^{\circ}C$) and maximization of the interaction between Pt and titania. The high thermal stability of $SiO_2/Pt@TiO_2$ enabled the investigation of CO oxidation studies at high temperatures, including ignition behavior, which is otherwise not possible on bare Pt nanoparticles due to sintering [3]. It was found that this hybrid catalyst exhibited a lower activation energy for CO oxidation because of the metal-support interaction. The concept of an ultra-thin active metal oxide coating on supported nanoparticles opens-up new avenues for synthesis of various hybrid nanocatalysts with combinations of different metals and oxides to investigate important model reactions at high-temperatures and in industrial reactions.

• The Plant Pathology Journal
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• 제21권3호
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• pp.283-287
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• 2005

Since the discovery of generation of $O_2^-$ in plant, many evidence for the oxidative burst (OXB) has been accumulated in various combinations of plant and pathogen or elicitor systems. $O_2^-$ generating system responsible for the OXB was coupled with oxidation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) in microsomal fraction isolated from sliced aged potato tuber slices which were treated by hyphal wall components elicitor from Phytophthora infestans (HWC). We developed new assay method for quantitative measurement of oxygen radical $O_2^-$ by using electron spin resonance (ESR) analysis during elicitor­induced OXB on the surface of plant tissues. The ESR analysis using an $O_2^-$ trapper, Tiron (1,2-dihydroxy-3,5­benzenedisulfonic acid), provided a convenient assay for detecting only $O_2^-$ during elicitor-induced OXB producing various active oxygen species (AOS) on plant tissue surface. Tiron was oxidized to Tiron semiquinon radical by $O_2^-$. Quantity of the radical signal was measured by specific spectra on ESR spectroscopy. The level of $O_2^-$ was high in from surface of potato tuber tissue treated with hyphal cell wall elicitor (HWC) from Phytophthora infestans. There was no secondary OXB induction by $H_2O_2$ treatment in plant.

• 대한치과교정학회지
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• 제51권4호
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• pp.270-281
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• 2021

Objective: The aim of this in vitro study was to evaluate the changes in friction between orthodontic brackets and archwires coated with aluminum oxide (Al₂O₃), titanium nitride (TiN), or chromium nitride (CrN). In addition, the resistance of the coatings to intraoral conditions was evaluated. Methods: Stainless steel canine brackets, 0.016-inch round nickel-titanium archwires, and 0.019 × 0.025-inch stainless steel archwires were coated with Al₂O₃, TiN, and CrN using radio frequency magnetron sputtering. The coated materials were examined using scanning electron microscopy, an X-ray diffractometer, atomic force microscopy, and surface profilometry. In addition, the samples were subjected to thermal cycling and in vitro brushing tests, and the effects of the simulated intraoral conditions on the coating structure were evaluated. Results: Coating of the metal bracket as well as nickel-titanium archwire with Al₂O₃ reduced the coefficients of friction (CoFs) for the bracket-archwire combination (p < 0.01). When the bracket and stainless steel archwire were coated with Al₂O₃ and TiN, the CoFs were significantly lower (0.207 and 0.372, respectively) than that recorded when this bracket-archwire combination was left uncoated (0.552; p < 0.01). The friction, thermal, and brushing tests did not deteriorate the overall quality of the Al₂O₃ coatings; however, some small areas of peeling were evident for the TiN coatings, whereas comparatively larger areas of peeling were observed for the CrN coatings. Conclusions: Our findings suggest that the CoFs for metal bracket-archwire combinations used in orthodontic treatment can be decreased by coating with Al₂O₃ and TiN thin films.

• Mycobiology
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• 제40권3호
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• pp.164-167
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• 2012

The effects of aeration through lid filters on the hyphal growth of Lentinula edodes (oak mushroom) in sawdust cultivation bags were investigated. The aeration treatment levels were traditional 27 mm hole cotton plugs, cotton balls and combinations of seven hole sizes ${\times}$ two hole positions (up and under) in the lids covering plastic bags containing 1.4 kg sawdust medium at 63% moisture that had been autoclaved for one hour and inoculated with sawdust spawn of L. edodes strain 921. Aeration treatment effects were measured based on the $CO_2$ concentration at the 15th wk, as well as the hyphal growth rate and degree of weight loss of bags every 14 days for 15 wk. In bags with traditional cotton plugs, the $CO_2$ concentration was $3.8{\pm}1.3%$, daily mean hyphal growth was $2.3{\pm}0.6mm$ and daily mean weight loss was $0.84{\pm}0.26g$. In the bags with 15 mm diameter holes, the $CO_2$ concentration was $6.0{\pm}1.6%$, daily hyphal growth was $2.8{\pm}0.2mm$ and daily weight loss was $0.86{\pm}0.4g$. The bags with 15 mm holes had a higher $CO_2$ concentration and lower water loss than bags with other hole sizes, but the hyphal growth was not significantly different from that of other bags. The weight loss of bags increased proportionally relative to the lid hole sizes. Taken together, these results indicate that traditional cotton plugs are economically efficient, but 15 mm hole lids are the most efficient at maintaining hyphal growth and controlling water loss while allowing $CO_2$ emissions.