• Journal of the Korean Chemical Society
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• v.35 no.5
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• pp.452-460
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• 1991

The chemical evidence for involvement of singlet oxygen during photoirradiation for 2-ethylanthracene [2-EA] and 9-phenylanthracene [9-PA] was based on the rapid decomposition of 1,3-diphenylisobenzofuran [DPBF] in methanol-water mixture and aqueous CTAB, and SDS micellar solutions. The average microenvironmental polarities of 2-EA and 9-PA were estimated by UV spectroscopic characteristics sensitive to the polarity of solvent. When 2-EA and 9-PA were solubilized in aqueous CTAB, SDS and Brij 35 solutions, their average microenvironmental polarities were polar, and their microenvironmental polarity parameter showed little dependence on the ionic properties of the micelles. The average microenvironmental polarity of 2-EA was similar to the polarity of 40% (w/w) aqueous ethanol, and that of 9-PA was similar to the polarity between 30 and 40% (w/w) aqueous ethanol. It was found that the greater part of these species might be distributed at the surface of micelles when they were solubilized in aqueous micellar solutions. The methanol-water mixture solution appeared to have characteristics more favorable for photooxidation reaction than aqueous micellar solutions.

• Korean Journal of Plant Tissue Culture
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• v.27 no.1
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• pp.19-23
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• 2000

The experiment was carried out to investigate the influence of light condition and polarity of explant on adventitious shoot formation from cotyledon of apple in vitro The treatment of light culture after 10days dark treatment showed effective result than other treatments on the rate of adventitious shoot formation on light intensity treatments and also the treatment of blue light treatment after 4days dark treatment showed more effective result than other treatments in light quality treatments. The polarity of explant influence on adventitious shoot formation. Adventitious multiple shoot formation occured at the proximal end of an excised cotyledon. In other words. shoot organogenesis occured at the proximal cut surfaces of both proximal and distal explants rather than at the distal cut surface of proximal explants.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.52.1-52.1
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• 2018

We investigate initial Fe/O enhancements for 44 large gradual solar energetic particles events from 2010 to 2014 and examine the associations of the Fe/O enhancements with the structures of the heliospheric current sheet (HCS). For this study, we use STEREO SIT Fe and O data in 0.32-0.45 MeV channel as well as ACE ULEIS Fe and O data in 0.32-0.64 MeV channel. We determine 1) the magnetic polarities of the SEP source regions using the potential field source surface (PFSS) model of the coronal field and 2) the spacecraft magnetic footpoints with Parker spiral approximation of interplanetary magnetic field using the in-situ measurements of STEREO and ACE. We find that 29 out of 44 events have initial Fe/O enhanced more than 5 times of the typical gradual event values. In the 6 events, the enhancements are simultaneously observed by two spacecraft. There is a tendency that the high Fe/O enhancements are observed near SEP source regions. It is also noted that the Fe/O enhancements are associated with the polarity of the magnetic footpoints. The high Fe/O enhancements are usually observed where their footpoints lie in the same polarity regions of SEP sources rather than the opposite polarity regions. Although Fe/O enhancements could be due to a transport effect and/or a flare contribution, our result implies that the structure of HCS is likely to affect particle propagations in the interplanetary space.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1525_1526
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• 2009

In this paper, we have studied the bulging phenomenon of ink-jet printed silver lines. The used silver inks are DGP-40LT-15C and DGH-55HTG of Advanced Nano Product (ANP) Company. We investigated the behavior of bulging by changing the polarity of the inks, the surface energy of substrate and droplet spacing in printing. The contact angle of the polar inks increased much more sensitively than the nonpolar ink as the surface energy of the substrate increases. In the case of the nonpolar ink, the bulging phenomenon occurred seriously as the droplet spacing decreased at the constant surface energy.

• 전기의세계
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• v.30 no.3
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• pp.172-176
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• 1981

The reduction in the breakdown field strength due to electrode surface roughness was calculated by applying the streamer breakdown criterion and the surface roughness factor, and measurements of static breakdown voltage for a gap with an artificial protrusion were made under the uniform field at pressures up to 4 bar in pressurized $SF_{6}$. The effect of polarity of highly stressed electrode on the breakdown field strength was also investigated. The measurements have shown that the measured breakdown levels for a protrusion located on the cathode agree with those calculated and the values measured with an identical anode protrusion are substantially higher and more scattered. This may be explained if it assumed that a high rate of production of initiatory electrons is maintained at the tip of a cathode protrusion by field emission. In practical point of view, the breakdown levels in pressurized $SF_{6}$ can be bereliably estimated from the values calculated.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.2
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• pp.83.2-83.2
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• 2011

The emergence of a magnetic flux tube (flux emergence) is a process of transporting magnetic field from the solar interior to the atmosphere. This process naturally produces bipolar structure at the surface, in which emerging field lines simply connect opposite polarities, while observations suggest that the surface distribution of magnetic field is more complicated than a simple bipole. This study is aimed at solving this apparent mismatch between the model and observations, showing how the surface distribution changes from a simple bipolar distribution to a quadrupolar-like one, where a half-turn rotation of the polarity inversion line plays an important role. We explain the physical reason of this half-turn rotation and also discuss a possible configuration of filament magnetic field in terms of the quadrupolar-like structure formed via flux emergence.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.143-146
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• 2002

Saponins are glycosidic compounds present in many edible and inedible plants. Structurally, they are composed of a lipid-soluble aglycone consisting of either a sterol or, more commonly, a triterpenoid and water-soluble sugar residues differing in type and amount of sugars ［1］. Because of their amphiphilic nature, they are highly surface-active. Their biological activity is closely related to the chemical structures that determine the polarity, hydrophobicith and acidity of compounds ［1］. (omitted)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.343-348
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• 1992

Using the real-time image processing technique, we have developed an automatic visual inspection system which detects the defects of the surface muonted components in PCB( missing components, mislocation, mismounts, and reverse polarity, etc ) and collects the quality control and production management data. An image processing system based on a commercial parallel processor, TRANSPUTER by which the image processing time can be largely reduced was designed. Analyzing the collected data, the proposed inspection system contributes to the productivity improvement throughthe reduction of defective rate.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.13-15
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• 2006

The effects of plasma treatment on the surfaces of the FR-4 (Flame Resistant-4) and copper substrates are investigated in terms of X-ray photoelectron spectroscopy (XPS), contact angle, and atomic force microscopy (AFM). The adhesion strengths of the underfills/FR-4 substrate and underfills/copper substrate are also studied. As experimental results, the plasma treatments of FR-4 and copper substrate surfaces yield several oxygen complexes in hydrophilic surfaces, which can play an important role in increasing the surface polarity, wettability, and adhesion characteristics of the underfills/substrates.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.385-390
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• 1999

Surface corona discharge characteristics of a dc corona charged ferroelectric pellet barrier have been investigated experimentally. Electric charges stored on the surfaces of the ferroelectric pellets by a dc corona discharge provide partial electric fields on the surfaces of the ferroelectric pellets, which could generate surface corona discharges on the ferroelectric pellets. This system utilizes both the surface discharges on the ferroelectric pellet barrier and the corona discharge between corona tip and mesh electrode. Positive and negative dc voltages were applied to the tip to generate partial discharges, and corona currents were estimated to investigate the buildup charge on ferroelectric pellets as a function of the applied time and the charge relaxation time constants of ferroelectric pellets. As a result, in the case of the negative corona discharge with the ferroelectric pellet barrier, the mean corona current and ozone generation increase greatly, and the surface discharges on the ferroelectric pellets can be fenerated efficiently. It is also found that, charge relaxation time, dielectric constants offerroelectric pellets, polarity of applied voltage and applied time affected to the surface discharges among the ferroelectric pellets.