• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1785-1791
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• 2010

This paper describes a separable microfluidic device fabricated with PDMS (polydimethylsiloxane) and glass. The device is used for sample preparation involving cell lysis and the DNA purification process. The cell lysis was performed for 2 min at $80^{\circ}C$ in a serpentine-type microreactor ($20 {\mu}l$) using a Au microheater that was integrated with a thermal microsensor on a glass substrate. The DNA that was mixed with other residual products during the cell lysis process was then filtered through a new filtration system composed of microbeads (diameter: $50 {\mu}m$) and PDMS pillars. Since the entire process (sample loading, cell lysis reaction, DNA purification, and sample extraction) was performed within 5 min in a microchip, we could reduce the sample preparation time in comparison with that for the conventional methods used in biochemistry laboratories. Finally, we verified the performance of the sample preparation chip by conducting PCR (polymerase chain reaction) analysis of the chip product.

• Proceedings of the Costume Culture Conference
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• 2004.04a
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• pp.44-46
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• 2004

심하게 퇴색된 출토 복식유물의 경우 유물의 고유색을 알지 못함은 물론 사용된 염료의 종류를 알지 못함으로 인하여 유물의 보존처리 및 장기간 보관과 전시에 큰 어려움을 지닌다. 이화학 분야에서는 미지시료의 기초 성분분석 방법으로서 thin layer chromatography(TLC)법이 오래 전부터 사용되었는데, 퇴색된 복식유물의 염료분석을 다룬 일부 선행연구에서는 이를 활용하여 유물의 염료를 판정하였다(Kharbade ＆ Agrawal, 1985; Schweppe, 1989). (중략)

• Food Science and Preservation
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• v.17 no.2
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• pp.190-195
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• 2010

Pressure, used as a minimal processing technology in the food industry, is a valuable tool ensuring microbiologically safe, shelf-stable fruit and vegetable production. Pressure could be used to deliver a greater variety of minimally processed products, as demanded by today's consumers. Weevaluated the effect of <400 MPa pressure, applied during chilling, on fresh fruit purees (strawberry, kiwi, aloe, and pomegranate) and vegetable extracts (from carrot and spinach) during cold storage (<$10^{\circ}C$) for 15-20 days. Samples were prepared in a processing facility in which total plate counts of falling and floating bacteria were controlled at $1{\times}100-10^1$ CFU/plate and $1{\times}10^2-10^3$ $CFU/m^3$ under conditions of $21-25^{\circ}C$ and 55-60% relative humidity. The aerobic plate counts of raw materials were less than $1{\times}10^3$ CFU/g. Evaluation parameters included microbiological safety, vitamin content, and sensory qualities. Although the overall quality of non-treated samples deteriorated with storage time at $10^{\circ}C$, samples pressurized at 250-350 MPa at $5-7^{\circ}C$ for 10 min showed less change, with no significant difference in microbiological safety, vitamin content, or sensory quality. The use of pressure extended the shelf-life during storage at $10^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.100-107
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• 2017

This study was conducted to evaluate the quality characteristics of got mul-kimchi during storage by type of kimchi container using a plastic ark shell. The pH level, acidity, hardness, color, sensory evaluation, and microbiological activity were performed. Kimchi containers were prepared with 0%, 2%, and 3% plastic ark shell. The pH level of 2% container samples showed no significant difference compared with that of the control, whereas pH levels of 3% container samples were significantly (P<0.05) higher than those of the control and 2% sample. Acidity was not different among treatments up to 4 weeks, whereas acidity of 3% container samples was significantly (P<0.05) lower than those of the control and 2% samples after 8 weeks. Hardness significantly decreased (P<0.05) upon 0, 2, and 3% treatments with increasing storage time, but there was no significant difference among the treatments. Hunter color L values increased in the order of 0, 3, and 2% with increasing storage time. In sensory evaluation of crunchiness, 3% container samples had significantly (P<0.05) higher crunchiness than the control. Total viable cells in the 3% container with got mul-kimchi were significantly (P<0.05) lower than those of other samples at 12 and 16 weeks of fermentation. Numbers of lactic acid bacteria in the 2% and 3% container samples were significantly (P<0.05) lower than those of the control samples after 16 weeks of fermentation. These results show that the plastic ark shell kimchi container extended storage compared with the control.

• Korean Chemical Engineering Research
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• v.51 no.2
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• pp.263-266
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• 2013

It was investigated the electrochemical characteristics of the Ni-MH battery by hydrophilic process. For adopting the Ni-MH battery in water-electrolyte, polyolefin separator was processed the hydrophilic treatment. No treatment sample did not meet KS standard (KSC 8544) but hydrophilic treatment ones satisfied with the KS standard in electrochemical characteristics, such as discharge performance, retention capacity, and cycle performance. All hydrophilic treatment samples showed similar battery performances. Among them, sulfonation treatment sample exhibited the highest value in aspect of capacity retention rate (> 88%). Furthermore, fluoride treatment sample showed the best cycle performance during battery test. This sample maintained a good cycling performance until $1,480^{th}$ cycle, which was about 3 times as compared with that of KS standard (500 cycle).

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.2
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• pp.176-180
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• 1986

A study was carried out to investigate the threshold values of four taste qualities by using electrogustometer for Korean female college students. The mean values of taste threshold before the treatments were for $7.5{\mu}A$, sweet taste area, $19.6{\mu}A$, salty taste area, $23.5{\mu}A$, sour taste area, $18.4{\mu}A$, bitter taste area and $50.7{\mu}A$, middle area, respectively. The thresholds of taste for the each area of tongue of the after-treatments were more sensitive than those of the before-treatments except the after-treatment with sodium chloride in which the sensitivity was much reduced. There were no significant differences between the thresholds of left and right side of the tongue. (p＜0.05). Taste qualities of electrical stimuli were also evaluated by using electrogustometer. The major tastes (Approx. 90%) of the feelings for the electrical stimuli were metallic, sour, bitter and salty.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.318-323
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• 2011

대규모 화재실험 또는 실제 화재에서 발생되는 독성가스의 분석은 화재가스에 대한 샘플링, 시료전처리, 분석데이터 처리 등의 여러 가지 문제로 인해 측정이 불가능하였다. 본 논문에서는 개방형 FT-IR 장비를 활용하여 대공간에서 발생되는 유해가스를 직접적인 접촉 없이 원거리에서 검출하는 실험적 연구를 수행하여 측정 가능성을 입증하였다.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.551-557
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• 2019

The purpose of this study was to investigate the changes of flavor and taste characteristics of black pepper treated with three different nonthermal sterilization methods, which are intense pulsed light (IPL), ultraviolet (UV), and cold plasma (CP). Also, the sensorial and instrumental evaluation of black pepper before and after nonthermal treatments were analyzed. As a result of color value, UV and CP treatments did not show chromacity difference (ΔE), but IPL treatment showed a significant difference of 6.58. Piperine contents of sample before nonthermal treatments was 10.7±0.53 mg/g and the piperine contents of all samples decreased after nonthermal treatments. The result of the electronic nose analysis were divided into two groups before and after nonthermal treatments, and divided into three group by principle component analysis. According to the intensity test, after nonthermal treatments, all sample had low flavor and taste, and the intensity was in the order of IPL, CP, and UV. In thirteen sensory attribute languages developed through quantitiative descriptive analysis (QDA), the intensity value of the samples were low after nonthermal treatments.

• Food Science and Preservation
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• v.22 no.3
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• pp.452-457
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• 2015

This study was conducted to evaluate the quality characteristics of pickled radish wrap supplemented with calcium chloride ($CaCl_2$) at different concentrations. With $CaCl_2$ supplementation, initial pH and acidity were 3.8~4.0 and 2.7~3.0% (w/v), respectively. During the 28 day-preservation at $4^{\circ}C$ or $50^{\circ}C$, the initial pH and acidity were maintained. However, when the pickled radish wrap was preserved at $25^{\circ}C$, it had lower pH (by 0.5) and higher acidity (by 1.9~2.2%) when compared with the initial values. The difference in color (${\Delta}E$-value) of the pickled radish wrap preserved at $50^{\circ}C$ was significant (${\Delta}E$-value 23~27), though the hardness of the sample prepared at $4^{\circ}C$ or $25^{\circ}C$ showed no distinguishable differences at various concentrations of $CaCl_2$ supplementation (0.1, 0.2, 03, 0.4, and 0.5%). However, once preserved at $50^{\circ}C$, it resulted in the greater hardness with the higher concentrations of $CaCl_2$ supplementation. In terms of softness, the overall trend in changes was similar to the hardness. A sensory evaluation using the samples preserved at $4^{\circ}C$ for 28 days demonstrated that the preparation with 0.4% $CaCl_2$ ranked highest in taste, hardness and overall acceptability. It wass suggested that supplementation with 0.4% $CaCl_2$ would be most appropriate to improve the textural properties of pickled radish wrap while maintaining its organoleptic quality.

• Journal of the Korean Chemical Society
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• v.39 no.2
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• pp.28-81
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• 1995

Inductively coupled plasma atomic emission spectrometry was used for the determination of all 14 rare earth elements (REE) in geological materials. Samples were decomposed by using acid digestion followed by alkaline fusion. Group separation of the REE was achieved by solvent extraction with TOPO (trioctylphosphine oxide) and back extraction into HCl. The results for standard rock sample, AGV-1, showed a good agreement with those obtained by US Geological Survey as well as reported values in other articles.