• Atmosphere
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• v.26 no.1
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• pp.185-192
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• 2016

In this paper, I studied about historical seasonal subdivision system and a theory of traditional monthly order, which was used for so long from Koryo dynasty to the late of Choseon dynasty in Korean histoy. Especially, I took note of the fact that there used the table of solar terms and meteorological observation what we called the table of Kihoo-pyo in the historical Sunmyung-calendar and the Soosi-calendar during the Koryo dynasty. This table of Kihoo was developed for explaining meteorological change during a year at that time. Here are largely four elements related meteorological nature : the first is the list of 24 solar terms, and the second is 12 monthly seasonal terms and 12 monthly central terms, the third is about four right hexagon based I-ching, the fourth is 72 meteorological observations called 72-hoo. Among them, the 72-hoo system is important to know how premodern people observed natural materials including animals and plants, weather, climate about meteorological phenomena according to the seasonal change or solar terms' change during a year. I argued in this article to need developing modern new table of Kihoo system like that, in order to show common people to recognize annual meteorological change more easy and clear. I also argued to need a distinct definition of meteorological seasons from a view point of modern meteorology.

• Journal of Astronomy and Space Sciences
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• v.24 no.2
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• pp.91-98
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• 2007

The existence of the North-South asymmetry of the solar activity is widely accepted even though the phenomenon is not yet satisfactorily understood. We have studied the temporal variations in the North-South asymmetry of the sunspot area during the period from May in 1874 to April in 2007. The combined data have been examined for periodicity in the solar activity North-South asymmetry. We have found that (i) solar northern and southern hemispheres show an asymmetric behavior, in terms of a sunspot area, (ii) sunspot areas in northern and southern hemispheres show clearly the 11 year periodicity when they were analyzed separately, as they do when analyzed together, (iii) in addition to the general 11 year periodicity in both northern and southern hemisphere solar activities, there are also noticeable shorter periodicities other than the 11 year periodicity in the asymmetry in North-South activity. Finally, we conclude by pointing out the importance of studying the North-South asymmetry of the solar activity.

• The Journal of the Korea Contents Association
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• v.22 no.10
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• pp.195-212
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• 2022

Based on the kinetic typography principle and the structure features of Chinese characters, this study took the Chinese'24 solar terms' theme dynamic poster as the research object, explored the visual expression of dynamic Chinese characters, and tried to summarize the visual expression law of Chinese characters in dynamic poster design. It can be found that, there could be 6 different types of Chinese character expressions in the 24 solar terms poster design. Among them, 'Drawing' design method has the meaning of text structure and form expression, and 'Assembling' design method has the meaning of text stroke and texture association, also, 'Forming' design method bring its meaning through stroke deformation, 'Transforming' design method conveys the content through text disintegration, 'Replacing' design method mainly bring the meaning through simulation, while 'Rotation' design method always express through visual three-dimensional and space. Finally, the findings could not only provide analytical logic and methods for the expression of Chinese characters in dynamic poster design, but also fill the lack of formative research on dynamic Chinese characters, which hopefully provide basic information for the research related to dynamic Chinese character structure, as well as the dynamic poster designers.

• Bulletin of the Korean Chemical Society
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• v.24 no.10
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• pp.1501-1504
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• 2003

Single-wall carbon nanotubes (SWCN) were integrated in $TiO_2$ film and the beneficial influence on the dyesensitized solar cells in terms of improved photocurrent was studied in the light of static J-V characteristics obtained both under illumination and in the dark, photocurrent transients, IPCE spectra and impedance spectra. Compared with a solar cell without SWCN, it is established that the photocurrent density of the modified cell increases at all applied potentials. The enhanced photocurrent density is correlated with the augmented concentration of electrons in the conduction band of $TiO_2$ and with increased electrical conductivity. Explanations are additionally corroborated with the help of SEM, Raman spectra and dye-desorption measurements.

• Journal of Astronomy and Space Sciences
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• v.34 no.1
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• pp.55-65
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• 2017

We studied the hour-lines of six extant Yangcheon-cheoks in Korea. To find whether Yangcheon-cheok was used in the whole area of Korea, we calculated the length of shadows of Yangcheon-cheok on the Korean Peninsula, Nanjing and Beijing as well as Hanyang (Seoul), according to 24 solar terms. Comparing the length of shadows with hour-lines of those relics, we could find that Yangcheon-cheok was suitable for use at limited times (from 9:00 to 15:00) during the year. Also, this sundial is more appropriate for use at low latitudes than high ones. Among existing relics, that of Seoul Museum of History made with porcelain was much more suitable to use at Hanyang and its higher latitude. Lee's collection was also suitable to use at Nanjing. It is certain that Yangcheon-cheok was a portable sundial which could be used from nine to fifteen of clock all the year around except for the winter season.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.23-36
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• 2015

The temperature change patterns of climatic solar terms and their climatic fitness were analyzed. Harmonic analysis based on thirty-year(1981-2010) time-series data from sixty one weather stations across South Korea showed that the central peaks of the extreme heat had shifted toward start of autumn with increasing mean temperature. The overall climatic fitness of solar terms, such as major heat, frost descent, major snow, and major cold, was low, and it showed significant regional variations. The actual meteorological phenomenon representing each climatic solar term was observed much later than the day of the solar term at most weather stations. The number of observations, where an actual meteorological condition for each climatic solar term was recorded within ${\pm}1$ week from the day of that solar term, ranged only from 7.7% to 40.4% of the entire data. Study results also showed that the climatic fitness of major heat, frost descent, and major snow gradually changed in the east-west direction. Major cold, a solar term with higher climatic fitness, was influenced more strongly by latitude than longitude. Considering geographically uneven magnitude and trends in temperature changes, rearrangement and adjustment of time intervals between the solar terms may help us improve their applicability as realistic indicators of seasonal changes.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.82-82
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• 2015

Industrial crystalline silicon (c-Si) solar cells with using a screen printing technology share the global market over 90% and they will continue to be the same for at least the next decade. It seems that the $2^{nd}$ generation and the $3^{rd}$ generation technologies have not yet demonstrated competitiveness in terms of performance and cost. In 2014, new world record efficiency 25.6% (Area-$143.7cm^2$, Voc-0.740V, $Jsc-41.8mA/cm^2$, FF-0.827) was announced from Panasonic and its cell structure is Back Contact $HIT^*$ c-Si solar cell. Here, amorphous silicon passivated contacts were newly applied to back contact solar cell. On the other hand, 24.9% $TOPCon^{**}$ cell was announced from Fraunhofer ISE and its key technology is an excellent passivation quality applying tunnel oxide (<2 nm) between metal and silicon or emitter and base. As a result, to realize high efficiency, high functional technologies are quite required to overcome a theoretical limitation of c-Si solar cell efficiency. In this presentation, Si solar cell technology summarized in the International Technology Roadmap for Photovoltaics ($^{***}ITRPV$ 2014) is introduced, and the present status of R&D associated with various c-Si solar cell technologies will be reviewed. In addition, national R&D projects of c-Si solar cells to be performed by Korea University are shown briefly.

• Publications of The Korean Astronomical Society
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• v.34 no.3
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• pp.49-65
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• 2019

We investigate the provenance and the changes in the timekeeping system focusing on official records such as almanacs and textbooks published by the government after the solar calendar was introduced. We found that the solar calendar and the 12-hour clock time first appeared in 1884 during Joseon dynasty, at that time the solar calendar was used at the open port in Busan to facilitate the exchanges with Japan. The 12-hour clock time first appeared in the 『Hansung Sunbo』 published by the government in 1884. We also found that the Joseon dynasty also used 12 diǎnzhōng or 12 diǎn. In addition, the term of the 'Sigan' first appeared in the first official academic textbook in August 1895, and the chapter related to time contained the information about 12-hour clock time instead of the 12 Shi. In 1908, the meaning of the solar time, the equation of time, and the differences in longitude with the adoption of Korean Standard Time were introduced. Meanwhile, the 24-hour clock time was first introduced in Joseon and applied to railway times in 1907. The 1946 almanac, the first issue after liberation, used the 12-hour clock time which uses 'Sango', 'Hao' and the 24-hour clock time started to be used from the following year and is still used to this day. Finally, the 12-hour clock time, which was introduced around 1884, was enacted as Article 44 of the law in 1900 and was revised again in 1905 and 1908. In Korea, the terms related to the time in the current astronomical calendar system were newly defined around 1884, 1896, and 1908, and gradually standardized through the establishment of laws.

• Korean Journal of Materials Research
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• v.16 no.1
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• pp.19-24
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• 2006

ZnO:Al(AZO) films prepared by rf magnetron sputtering on glass substrate and textured by post-deposition chemical etching were applied as front contact and back reflectors for ${\mu}c$-Si:H thin film solar cells. For the front transparent electrode contact, AZO films were prepared at various working pressures and substrate temperature and then were chemically etched in diluted HCl(1%). The front AZO films deposited at low working pressure(1 mTorr) and low temperature ($240^{\circ}C$) exhibited uniform and high transmittance ($\geq$80%) and excellent electrical properties. The solar cells were optimized in terms of optical and electrical properties to demonstrate a high short-circuit current.

• Journal of the Korean Association of Geographic Information Studies
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• v.22 no.3
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• pp.65-81
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• 2019

The twenty-four Solar Terms are Chinese traditional astronomical divisions that describe seasonal cycles of the year. Based on the analyses of meteorological data during 1979~2018, study results showed that the temperatures of the Solar Terms had increased in general in the Korean Peninsula. In North Korea, temperature increases were observed on 21 Solar Terms, and their seasonal mean temperatures were increased by $0.87^{\circ}C$, $1.19^{\circ}C$, $1.45^{\circ}C$, and $0.64^{\circ}C$ on average in spring, summer, fall, and winter, respectively. The duration of summer has lengthened due to the temperature rise in fall, and the magnitude of temperature change was greater in summer compared to winter. As for South Korea, increases in temperature were observed on 18 Solar Terms, and the temperature changes were more pronounced in fall and winter than spring and summer. The Great Snow temperature decreased more than any other Solar Terms during the study period, and this temperature change was observed both in North and South Koreas. The Great Cold, which represents the coldest day of the year, showed a significant temperature increase of $3.08^{\circ}C$, while the Slight Heat had a marginal temperature increase of $0.29^{\circ}C$. The hottest day and the first day of frost tended to come later than the Great Heat and the Frost's Decent. By contrast, the coldest day tended to occur later than the Great Cold in the study area. On average over the entire study period, the climatic fitness of the Great Heat and the Frost's Decent was higher in North Korea, and that of the Great Cold was higher in South Korea, respectively.