• 제목/요약/키워드: Sun:activity

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MAGNETIC HELICITY OF SOLAR ACTIVE REGIONS AND ITS IMPLICATIONS

  • SAKURAI T.;HAGINO M.
    • 천문학회지
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    • 제36권spc1호
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    • pp.7-12
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    • 2003
  • We have studied the magnetic helicity of active regions by using the data from (1) the photo-electric magnetograph of the Okayama Observatory (1983-1995) and (2) the video magnetograph of NAOJ/Mitaka (1992-2000). The latitude distribution of helicity showed a tendency that the regions in the north (south) hemisphere have negative (positive) helicities, respectively, which is already known as the hemispheric sign rule. If we look into the sign of helicity as a function of time, the sign rule was less definite or was reversed sometimes in the sunspot minimum phase. We also studied the relation between the magnetic helicity and the sunspot tilt angles, and found that these two quantities are positively correlated, which is opposite to the expectation of a theoretical model. The implications of this cycle-phase dependence of helicity signs and the correlation between magnetic he Ii city and sunspot tilt angles are discussed.

Studying the influence of the concentration of alkaline solution to the formation of TiO2 nanotube prepared by microwave-assisted hydrothermal method

  • Hao, Nguyen Huy;Cho, Sung Hun;Lee, Soo W.
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2014년도 추계학술대회 논문집
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    • pp.260-261
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    • 2014
  • $TiO_2$ nanotubes (TNT) synthesized by microwave-assisted hydrothermal method by using $TiO_2-P25$ as a precursor at hydrothermal temperature $150^{\circ}C$ in 4 hours. The concentration of alkaline solution is between 4M and 10M. Samples were characterized by X-ray diffraction (XRD), Raman spectroscopy (RS), Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) and UV-vis DRS spectroscopy. The results demonstrated the effects of the alkali concentration to the formation of nanotubes. The photocatalytic activity was investigated by degradation of Methylene Blue (MB).

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고객반응에 따른 CRM효과에 관한 연구 - 대전지역 백화점 의류제품 고객을 중심으로 - (A Study on Effect of CRM according to Customers' Response -Focused on clothing product customers of department store of Daejeon area-)

  • 박혜선;박선희
    • 한국생활과학회지
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    • 제14권3호
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    • pp.441-451
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    • 2005
  • The purpose of this study is to investigate the factors of CRM(Customer Relationship Management) activity and the difference in CRM effects according to customers responses. The investigators interviewed the buyers of three department stores in Daejeon area and surveyed 468 people aged over 20 who had ever shopped at those stores. For data analysis, we used factorial analysis, multiple regression analysis, path analysis, and ANOVA, etc., along with SPSS 10.0. The results of this study are as follows: 1) Six CRM activity factors were identified as 'Benefit & Information,' 'Service,' 'Customer Invitation,' 'Customer Contact,' 'Special Management,' and 'Purchase-related Help.' 2) Customer satisfaction of CRM-positive group was affected by such factors as 'Service,' 'Customer Invitation,' and 'Special Management,' and also customer loyalty directly by 'Customer Satisfaction' and 'Benefit & Information.' On the other hand, customer satisfaction of CRM-less-positive-group was influenced by the factors such as 'Service,' 'Purchase-related Help,' 'Customer Contact,' and 'Special Management,' and also customer loyalty directly by 'Customer Satisfaction' and 'Service.'

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Inhibition of the Calcineurin Pathway by Two Tannins, Chebulagic Acid and Chebulanin, Isolated from Harrisonia abyssinica Oliv.

  • Lee, Won Jeong;Moon, Jae Sun;Kim, Sung In;Kim, Young Tae;Nash, Oyekanmi;Bahn, Yong-Sun;Kim, Sung Uk
    • Journal of Microbiology and Biotechnology
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    • 제24권10호
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    • pp.1377-1381
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    • 2014
  • In order to discover and develop novel signaling inhibitors from plants, a screening system was established targeting the two-component system of Cryptococcus neoformans by using the wild type and a calcineurin mutant of C. neoformans, based on the counter-regulatory action of high-osmolarity glycerol (Hog1) mitogen-activated protein kinase and the calcineurin pathways in C. neoformans. Among 10,000 plant extracts, that from Harrisonia abyssinica Oliv. exhibited the most potent inhibitory activity against C. neoformans var. grubii H99 with fludioxonil. Bioassay-guided fractionation was used to isolate two bioactive compounds from H. abyssinica, and these compounds were identified as chebulagic acid and chebulanin using spectroscopic methods. These compounds specifically inhibited the calcineurin pathway in C. neoformans. Moreover, they exhibited potent antifungal activities against various human pathogenic fungi with minimum inhibitory concentrations ranging from 0.25 to over $64{\mu}g/ml$.

Latitudinal Distribution of Sunspot and North-South Asymmetry Revisited

  • Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
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    • 제35권2호
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    • pp.55-66
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    • 2018
  • The solar magnetic field plays a central role in the field of solar research, both theoretically and practically. Sunspots are an important observational constraint since they are considered a discernable tracer of emerged magnetic flux tubes, providing the longest running records of solar magnetic activity. In this presentation, we first review the statistical properties of the latitudinal distribution of sunspots and discuss their implications. The phase difference between paired wings of the butterfly diagram has been revealed. Sunspots seem to emerge with the exponential distribution on top of slowly varying trends by periods of ~11 years, which is considered multiplicative rather than additive. We also present a concept for the center-of-latitude (COL) and its use. With this, one may sort out a traditional butterfly diagram and find new features. It is found that the centroid of the COL does not migrate monotonically toward the equator, appearing to form an 'active latitude'. Furthermore, distributions of the COL as a function of latitude depend on solar activity and the solar North-South asymmetry. We believe that these findings serve as crucial diagnostic tools for any potential model of the solar dynamo. Finally, we find that as the Sun modulates the amount of observed galactic cosmic ray influx, the solar North-South asymmetry seems to contribute to the relationship between the solar variability and terrestrial climate change.