• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1590-1592
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• 2000

The time to tracking breakdown of treated filled specimen is longer than untreated filled specimen. And, after the RWDT, the surface of specimen by adding untreated filler appeared heavy erosion. It was found that the addition to surface treated filler. the better tracking resistance. In the RWDT, the breakdown specimen is not affected by the dry flashover voltage. despite the fact that the surface degradation of tracking test has different state on each specimen. This suggests that wet flashover voltage play an important role in evaluating of tracking and erosion on the surface degradation in tracking test. And, the flashover voltage of specimen under wet conditions are greatly affected by the salt concentration and degree of degradation by the RWDT. Because of hydrophobicity and degree of degradation by the RWDT, the flashover voltage of treated filled specimen is higher than that of untreated filled specimen. Different types of specimen may have different hydrophobicity and their surface state under contaminated conditions may not be the same. It is assumed that this phenomenon is related to the decrease in hydrophobicity of the surface of the materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.119-122
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• 2000

Recently polymer insulators are being used for outdoor high voltage applications. Polymer insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymer insulators are a relatively new technology, but their expected life is still unknown. Therefore these estimating technique are very important. Their life time is related to weathering and operating condition. Multi-aging test is requested because aging factor is occurred by multi-aging than unique aging. The aging test about polymer insulators have mainly carried out by IEC 61109. This paper presents multi-stress chamber experiments and tracking wheel test to examine the tracking and erosion performance of polymer insulator for transmission. Multi-stress testing is able to demonstrate deficiencies of polymer insulator materials and designs, including the nature of interfaces in insulation design. We have investigated IEC 61109 Annex C (5000h aging test) and CEA tracking wheel test as test methods of artificial accelerated aging. The aging degree of polymer insulator is estimated by leakage current, measurement of hydrophobicity degree, damage conditions of insulator surface, withstand voltage test etc.

• Journal of Microbiology and Biotechnology
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• 제22권10호
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• pp.1367-1374
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• 2012

Pleurocidin, a 25-mer antimicrobial peptide, has been known to exhibit potent antibacterial activity. To investigate the functional roles in N- and C-terminal regions of pleurocidin on the antibacterial activity, we designed four truncated analogs. The antibacterial susceptibility testing showed that pleurocidin and its analogs exerted antibacterial effect against various bacterial strains and further possessed specific activity patterns corresponding with their hydrophobic scale [pleurocidin > Anal 3 (1-22) > Anal 1 (4-25) > Anal 4 (1-19) > Anal 2 (7-25)]. Fluorescence experiments using 1,6-diphenyl-1,3,5-hexatriene (DPH) and 3,3'-dipropylthiadicarbocyanine iodide [$diSC_3(5)$] indicated that the differences in antibacterial activity of the peptides were caused by its membrane-active mechanisms including membrane disruption and depolarization. Blue shift in tryptophan fluorescence demonstrated that the decrease in net hydrophobicity attenuates the binding affinity of pleurocidin to interact with plasma membrane. Therefore, the present study suggests that hydrophobicity in the N- and C-terminal regions of pleurocidin plays a key role in its antibacterial activity.

• Reproductive and Developmental Biology
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• 제33권3호
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• pp.119-123
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• 2009

The two dimensional quantitative structure-activity relationships (2D-QSARs) models concerning the binding affinity constants ($p[Od.]_{50}$) between 2-cyclohexyltetrahydropyrane and 2-cyclohexyltetrahydrofurane analogues as substrates, and bovine odorant binding protein (bOBP) as receptor were derived by multiple regression analyses method and discussed. The statistical quality of the optimized 2D-QSAR model (5) was good (r=0.907). From the model, the binding affinity constants ($p[Od.]_{50}$) were dependent upon the optimal value ($(TL)_{opt.}$=2.737) of total lipole (TL) of substrate molecules. Based on these findings, the high active compounds predicted by optimized 2D-QSAR model (5) were 2-(dimethylcyclohexyl)tetrahydropyrane molecule and their isomer molecules. The binding affinity constants regarding bOBP of the tetrahydrofuryl-2-yl family compounds were dependent upon the hydrophobicity (logP) of whole substrate molecules. In any case of porcine odorant-binding proteins (pOBP), the constants were dependent upon the hydrophobicity (${\pi}x={\log}P_X-{\log}P_H$) of substituents (R) in substrate molecules. Also, from the optimal values of hydrophobic constant, the hydrophobicity for bOBP influenced ca. twice time bigger (bOBP>pOBP) than that for pOBP.

• 한국식품조리과학회지
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• 제9권1호
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• pp.43-51
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• 1993

Buckwheat protein isolate was tested for the effects of pH, addition of sodium chloride and heat treatment on solubility, emulsion capacities, emulsion stability, surface hydrophobicity, foam capacities and foam stability. The solubility of buckwheat protein isolate was affected by pH and showed the lowest value at pH 4.5, the isoelectric point of buckwheat protein isolate. The solubility significantly as the pH value reached closer to either ends of the pH, i.e., pH 1.0 and 11.0. The effects of NaCl concentration on solubility were as follows; at pH 2.0, the solubility significantly decreased when NaCl was added; at pH 4.5, it increased above 0.6 M; at pH 7.0 it increased; and at pH 9.0 it decreased. The solubility increased above $80^{\circ}C$, at all pH ranges. The emulsion capacity was the lowest at pH 4.5. It significantly increased as the pH approached higher acidic or alkalic regions. At pH 2.0, when NaCl was added, the emulsion capacity decreased, but it increased at pH 4.5 and showed the maximum value at pH 7.0 and 9.0 with 0.6 M and 0.8 M NaCl concentrations. Upon heating, the emulsion capacity decreased at acidic pH's but was maximised at pH 7.0 and 9.0 on $60^{\circ}C$ heat treatment. The emulsion stability was the lowest at pH 4.5 but increased with heat treatment. At acidic pH, the emulsion stability increased with the increase in NaCl concentration but decreased at pH 7.0 and 9.0. Generally, at other pH ranges, the emulsion stability was decreased with increased heating temperature. The surface hydrophobicity showed the highest value at pH 2.0 and the lowest value at pH 11.0. As NaCl concentrationed, the surface hydrophobicity decreased at acidic pH. The NaCl concentration had no significant effects on surface hydrophobicity at pH 7.0, 9.0 except for the highest value observed at 0.8 M and 0.4 M. At all pH ranges, the surface hydrophobicity was increased, when the temperature increased. The foam capacity decreased, with increased in pH value. At acidic pH, the foam capacity was decreased with the increased in NaCl concentration. The highest value was observed upon adding 0.2 M or 0.4 M NaCl at pH 7.0 and 9.0. Heat treatments of $60^{\circ}C$ and $40^{\circ}C$ showed the highest foam capacity values at pH 2.0 and 4.5, respectively. At pH 7.0 and 9.0, the foam capacity decreased with the increased in temperature. The foam stability was not significantly related to different pH values. The addition of 0.4 M NaCl at pH 2.0, 7.0 and 9.0 showed the highest stability and the addition of 1.0 M at pH 4.5 showed the lowest. The higher the heating temperature, the lower the foam stability at pH 2.0 and 9.0. However, the foam stability increased at pH 4.5 and 7.0 before reaching $80^{\circ}C$.

• 한국균학회지
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• 제38권1호
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• pp.69-74
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• 2010

세균갈색무늬병 병원균의 접종에 의해 심한 병징을 보이는 느타리 균주와 매우 약한 병징을 보이는 균주를 모균주로 선발하고, 각각의 모균주로부터 얻은 단핵균주의 교배를 통해 F1 교잡균주를 얻었다. 세균갈색무늬병 발병도가 다른 11개의 F1균주와 모균주의 자실체 표면의 소수성과 발병도를 조사하였다. 발병도와 소수성 사이의 상관계수는 2번의 독립된 실험에서 각각 0.68과 070이었다. 자실체의 발병도와 버섯재배사에서 조사한 발병율 사이의 상관계수는 각각 046과 0.52이었다. GFP을 발현시킨 Pseudomonas tolaasii을 자실체표면에 접종 후 공초점현미경으로 관찰한 결과 발병도가 낮은 균주의 자실체 표면에서보다 높은 균주의 자실체 표면에서 보다 많은 세균의 집단화가 관찰되었는데, 이 결과는 발병도가 높은 균주의 갓 표면에서 더많은 세균이 증식하였음을 의미한다. 이상의 결과는 느타리 자실체 표면의 소수성이 세균갈색무늬병 발병도에 영향을 미치는 것을 암시한다. 즉 세균현탁액 방울이 갓 표면에 오래 유지되면 더 심한 병징이 형성된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.782-782
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• 2003

• 대한약학회:학술대회논문집
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• 대한약학회 2001년도 Proceedings of International Convention of the Pharmaceutical Society of Korea
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• pp.291.1-291.1
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• 2001

• Food Science and Biotechnology
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• 제14권4호
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• pp.493-497
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• 2005

Probiotics are generally excreted within a few days if their ingestion in feces at the same rate as or even more quickly than a transit marker (meaning not clear). Ability of probiotics to adhere to intestine prolongs their persistence in gastrointestinal tract, allowing them to exert healthful effects longer. Hydrophobicities, zeta potentials, Alcian blue-binding capacities, and sedimentation profiles of Pichia farinosa SKM-1, P. anomala SKM-T, and Galactomyces geotrichum SJM-59 were determined to evaluate characteristic properties of cell surfaces responsible for adhesion. Results of intestinal Caco-2 cell line in vitro and murine intestine in vivo studies revealed these strains exhibit adhesive properties regardless of their cell surface hydrophobicity.

• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3378-3382
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• 2012

A superhydrophobic surface with a water contact angle > $150^{\circ}$ has attracted great interest from both fundamental and practical aspects. In this study, we demonstrated that hydrophobicity of a silica nanotube (SNT) array can be easily controlled by the SNT aspect ratio. In addition, the adhesive and anti-adhesive properties were controlled without modifying the hydrophobic surface. Various silica structures on a polydimethylsiloxane substrate were prepared using the desired alumina template. Bundle-arrayed and bowl-arrayed silica surfaces exhibited extraordinary superhydrophobicity due to the large frontal surface area and hierarchical micro/nanostructure. As the strategy used in this study is biocompatible and a wide range of hydrophobicities are capable of being controlled by the SNT aspect ratio, a hydrophobic surface composed of an SNT array could be an attractive candidate for bioapplications, such as cell and protein chips.