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        검색결과 129

        110.
        2021.03 KCI 등재 서비스 종료(열람 제한)
        Industrial emissions, mainly from industrial complexes, are important sources of ambient Volatile Organic Compounds (VOCs). Identification of the significant VOC sources from industrial complexes has practical significance for emission reduction. VOC samples were collected from July 2019 to June 2020. A Positive Matrix Factorization (PMF) receptor model was used to evaluate the VOC sources in the area. Four sources were identified by PMF analysis, including coating-1, coating-2, printing, and vehicle exhaust. The coating-1 source was revealed to have the highest contribution (41.5%), followed by coating-2 (23.9%), printing (23.1%), and vehicle exhaust (11.6%). The source showing the highest contribution was coating emissions, originating from the northwest to southwest of the sample site. It also relates to facilities that produce auto parts. The major components of VOC emissions from the coating facilities were toluene, m,p-xylene, ethylbenzene, o-xylene, and butyl acetate. Industrial emissions should be the top priority to meet the relevant control criteria, followed by vehicular emissions. This study provides a strategy for VOC source apportionment from an industrial complex, which is helpful in the development of targeted control strategies.
        111.
        2020.05 KCI 등재 서비스 종료(열람 제한)
        This study analyses the characteristics of volatile organic compounds (VOCs) emissions from the painting and printing facilities, as well as ambient VOCs at industrial complexes in Gwangju. The major components of VOCs emissions from painting facilities were toluene, acetone, 2-butanone, ethyl acetate, ethyl benzene, o-xylene and m,p-xylene. The printing facilities mostly emitted ethyl acetate, 2-butanone, acetone and toluene. Aromatics (49.9%) and oxygenated VOCs (43.6%) were dominant in painting facilities, while oxygenated VOCs (92.7%) were the largest group in printing facilities. The total hydrocarbon concentration (THC) in printing facilities was approximately six times higher than in the painting facilities. The painting and printing facilities use many solvents. Their THC concentrations differed considerably depending on the type of prevention facilities. To reduce THC, it is necessary to improve the prevention facilities and operating conditions. The dominant species of ambient VOCs in industrial complexes were investigated with toluene, ethyl acetate, 2-butanone, ethyl benzene, m,p-xylene, butyl acetate, o-xylene, hexane and acetone. Factor analysis of ambient VOCs showed that the main sources of the VOCs were organic solvents used in painting, coating, and printing, as well as automobile emissions.
        112.
        2019.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We investigate solar and lunar motions in the Seonmyeong (SM) calendar that was compiled by Xu, Ang of the Tang dynasty (A.D. 618–907) in China and used for 71 years from 822 to 892. This calendar was also used in Korea during the Goryeo dynasty (A.D. 918–1392) and in Japan for 823 years from 862 to 1684, the longest time among the three countries. Referring to historical documents of China, Korea, and Japan, we analyze the calendrical methods of calculating the daily apparent movements of the Sun and Moon in the SM calendar, which were considered their unequal motions, and compare the movements with the results of modern calculations for three periods in the Goryeo dynasty: 919, 1155, and 1392 years (i.e., the beginning, middle, and ending of the dynasty, respectively). We find that a quadratic equation was employed to obtain the daily movement of the Sun using physical quantities on the instant of each solar term, which was tabulated in its calendar book such as the Goryeosa (History of the Goryeo Dynasty). For quantitative analysis, we compute the mean absolute difference (MAD) of the daily apparent movement between the SM calendar and modern calculations and obtain 0.33, 0.30, and 0.31 arcmin for the periods of 919, 1155, and 1392 years, respectively. Meanwhile, we find relatively large MAD values in the daily movement of the Moon: 0.217, 0.284, and 0.240 degrees for each corresponding year. An interesting point is that the MAD value in the lunar motion shows the maximum in 1155 years, and is the minimum in the solar motion. In conclusion, we believe that this study will facilitate in the understanding of the SM calendar further, particularly in the calendrical methods of calculating sunrise, sunset, and eclipse times.
        113.
        2017.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this paper, we investigate the observations of Venus in daytime that are recorded in the Goryeosa (History of the Goryeo Dynasty, A.D. 918-1392). There are a total of 167 accounts of such observations in this historical book, spanning a period of 378 yr (from 1014 to 1392). These include six accounts where the days of the observation are not specified and two accounts where the phase angles are outside the calculation range of the equation used in our study. We analyze the number distribution of 164 accounts in 16 yr intervals covering the period from 1023 to 1391. We find that this distribution shows its minimum at around 1232, when the Goryeo dynasty moved the capital to the Ganghwa Island because of the Mongol invasion, and its maximum at around 1390, about the time when the dynasty fell. In addition, we calculate the azimuth, altitude, solar elongation, and apparent magnitude of Venus at sunset for 159 observations, excluding the eight accounts mentioned above, using the DE 406 ephemeris and modern astronomical algorithms. We find that the average elongation and magnitude of Venus on the days of those accounts were ~40° and -4.5, respectively, whereas the minimum magnitude was -3.8. The results of this study are useful for estimating the practical conditions for observing Venus in daylight with the naked eye and they also provide additional insight into the corresponding historical accounts contained in the Goryeosa.
        114.
        2015.07 서비스 종료(열람 제한)
        Small heat shock proteins (Hsps) are one of most conserved molecular chaperones that protect stress-inducible denaturation of substrates in living organisms. Small Hsps consist of a large subfamily categorized by subcellular localization ranging in size from 12 to 40 kDa. Here, we identified and characterized a small Hsp 16.9 gene (EsHsp16.9) from Siberian wild rye (Elymus sibiricus L.). EsHsp16.9 is a 456-bp cDNA with an open reading frame predicted to encode a 151-amino acid protein. It possesses a conserved ɑ-crystallin domain, which is a unique domain for small Hsps; shares high sequence similarity with cytosolic class I small Hsps among the small Hsp subfamily in Arabidopsis; and is close (96% similarity) to small Hsp in wheat. Northern blot analysis showed that EsHsp16.9 transcripts were enhanced by heat, drought, arsenate, methyl viologen, and H2O2 treatments. Moreover, we expressed and purified recombinant EsHsp16.9 proteins in Escherichia coli to confirm its activity as a molecular chaperone. We found that recombinant EsHsp16.9 exhibits effective molecular chaperone activity, as determined by inhibition of thermal aggregation of malate dehydrogenase (MDH), which is broadly used as a model substrate.
        115.
        2015.07 서비스 종료(열람 제한)
        To develop transgenic forage crops with enhanced tolerance to abiotic stress, we introduced an alfalfa Hsp23 gene expression vector construct through Agrobacterium-mediated transformation. Integration and expression of the transgene were confirmed by PCR, northern blot, and western blot analyses. Under normal growth conditions, there was no significant difference in the growth of the transgenic plants and the non-transgenic controls. However, when exposed to various stresses such as salt or arsenic, transgenic plants showed a significantly lower accumulation of hydrogen peroxide and thiobarbituric acid reactive substances than control plants. The reduced accumulation of thiobarbituric acid reactive substances indicates that the transgenic plants possessed a more efficient reactive oxygen species-scavenging system. We speculate that the high levels of MsHsp23 proteins in the transgenic plants protect leaves from oxidative damage through chaperon and antioxidant activities. These results suggest that MsHsp23 confers abiotic stress tolerance in transgenic forage crops and may be useful in developing stress tolerance in other crops.
        116.
        2015.07 서비스 종료(열람 제한)
        In order to improve high persistence and forage quality, through selection of various superior parental varieties for breeding and synthesis of them with new lines, there are ongoing worldwide studies aiming to enhance the quality of tall fescue through a traditional breeding method by selection and hybridization. A new tall fescue variety (Festuca arundinacea Schreb.), named Greenmaster3ho, was developed by the National Institute of Animal Science, Rural Development Administration in Korea from 2010 to 2014. For synthetic seed production of this new variety, five superior clones, 09XFa02, 09XFa03, 09XFa11, 09XFa13, and 09XFa14 were selected and polycrossed. The agronomic growth characteristics and forage production capability of the seeds were studied at Cheonan from 2010, and regional trials were conducted in Cheonan, Hoengseong, Jeju, and Jinju from 2012 to 2014. Greenmaster3ho showed enhanced disease resistance, persistence, and regrowth ability as compared to Fawn. The dry matter yield of Greenmaster 2 was 29% higher (15,119 kg/ha) than that of Fawn. However, the nutritive value of both varieties was similar. This study developed a new tall fescue variety with excellent environmental adaptability, aiming to make a contribution to the vitalization of the Korean grassland industry.
        117.
        2015.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        During the reign of King Sejong (世宗, 1418-1450) in the Joseon Dynasty, there were lots of astronomical instruments, including miniaturized ones. Those instruments utilized the technical know-how acquired through building contemporary astronomical instruments previously developed in the Song(宋), Jin(金), and Yuan(元) dynasties of China. In those days, many astronomical instruments had circles, rings, and spheres carved with a scale of 365.25, 100, and 24 parts, respectively, on their circumference. These were called the celestial-circumference degree, hundred-interval (Baekgak), and 24 direction, respectively. These scales are marked by the angular distance, not by the angle. Therefore, these circles, rings, and spheres had to be optimized in size to accomodate proper scales. Assuming that the scale system is composed of integer multiples of unit length, we studied the sizes of circles by referring to old articles and investigating existing artifacts. We discovered that the star chart of Cheonsang yeolcha bunyajido was drawn with a royal standard ruler (周尺) based on the unit length of 207 mm. Interestingly, its circumference was marked by the unit scale of 3 puns per 1 du (or degree) like Honsang (a celestial globe). We also found that Hyeonju ilgu (a equatorial sundial) has a Baekgak disk on a scale of 1 pun per 1 gak (that is an interval of time similar to a quarter). This study contributes to the analysis of specifications of numerous circular elements from old Korean astronomical instruments.
        118.
        2014.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this paper, we report the analysis of Korean historical records on the periodic Halley’s comet according to the period (i.e., the Three Kingdoms, Goryeo Dynasty, and Joseon Dynasty) using various sources such as the Samguksagi (The History of the Three Kingdoms), Goryeosa (The History of the Goryeo Dynasty), and Joseonwangjosillok (The Annals of the Joseon Dynasty). With regards to the apparition time of the comet for each return, we referred to the works of Kronk. For the Three Kingdoms period, we could not find any record relevant to Halley’s comet from the Samguksagi. Furthermore, we examined the suggestion that the phenomenon of “two Suns” which appeared on April 1, 760 (in a luni-solar calendar), as recorded in the Samgukyusa (The Legends and History of the Three Kingdoms), indicates an instance of the the daytime appearance of Halley’s comet. In contrast with the Three Kingdoms period, we found that all returns of Halley’s comet are recorded during the Goryeo Dynasty, although others have questioned some accounts. We also found that the appearance of Halley’s comet in 1145 is mentioned in a spirit-path stele made in 1178. For the Joseon Dynasty period, we found that all apparitions of the comet are recorded, as with the Goryeo Dynasty, except for the return of 1910, at which time the former dynasty had fallen. In conclusion, we think that this study will be helpful for understanding Korean historical accounts on Halley’s comet.
        119.
        2013.11 서비스 종료(열람 제한)
        In Korea, two decommissioning projects have been carried out due to retire of nuclear research facilities such as Korean research reactors (KRR-1 & KRR-2) and a uranium conversion plant (UCP). The decommissioning of the KRR-2 and a uranium conversion plant (UCP) at KAERI were finished completely by 2011, whereas the decommissioning of KRR-1 is currently underway. The large quantity of radioactive waste was generated during the decommissioning the KRR and UCF such as concrete waste, soil, combustible and non combustible waste. The volume reduction of the combustible wastes through the incineration technologies has merits from the view point of decrease in the amount of waste to be disposed of resulting in a reduction of the disposal cost. Incineration is generally accepted as a method of reducing the volume of radioactive waste. The incineration technology is effective treatment method that contains hazardous chemical as well as radioactive contamination. Incinerator burns waste at high temperatures. Incineration of a mixture of chemically hazardous and radioactive materials, known as“mixed waste,”has two principal goals: to reduce the volume and total chemical toxicity of the waste. Incineration itself does not destroy the metals or reduce the radioactivity of the waste. A proven melting technology is currently used for low-level waste (LLW) at several facilities worldwide. These facilities use melting as a means of processing LLW for unrestricted release of the metal or for recycling within the nuclear sector. Fig. 1 shows the schematic diagram of the oxygen-enriched incineration (OEI) and melting facility. The oxygen-enriched incinerator located at the KAERI. The system consists of a waste preparation system, incineration system, off-gas cooling system, and off-gas treatment system. Demonstration incineration facility took over the responsibilities of KHNP for decommissioned combustible waste. After taking over the demonstration incineration facility from KHNP, the facility was modified, and work toward the licensing procedure, and an extension of the object waste including alpha-bearing waste and increase incineration capacity, began in June 2011. The melt decontamination technology is the most effective treatment method for decommissioned metal waste. Melting for size reduction would require no prior surface decontamination and very little sorting of the waste material. Also, the recycling or volume reduction of the metallic wastes through the melt decontamination technologies has merits from the view point of an increase in resource recycling as well as a decrease in the amount of waste to be disposed of resulting in a reduction of the disposal cost and an enhancement of the disposal safety. Melt facility consist of four system such as preparation system, melting system, ingot treatment, and off-gas treatment system. The decommissioned combustible waste has been incineration by incinerator from last year. In case of metal waste, metal waste will be melt for self-disposal and volume reduction by induction furnace. Combustible wastes were treated by incinerator and ash dispose permanently site. In case of metal wastes is treated by induction furnace and slag dispose permanently site and ingot will be reuse.
        120.
        2013.07 서비스 종료(열람 제한)
        Abiotic stress is the major limiting factor of forage crops growth and yields. The objective of this work was to study the stress tolerance and regeneration capability of transgenic forage crops carrying a MsHSP23 gene, encoding a alfalfa mitochondrial sHSP protein. The expression of the MsHSP23 gene was confirmed in bacteria, recombinant mHSP23 conferred tolerance to salinity and arsenic stress. Furthermore, mHSP23 was cloned in a plant expressing vector and transformed into forage crops such as alfalfa, tall fescue and bent grass. The transgenic plants exhibited enhanced tolerance to salinity and arsenic stress conditions. In comparison to wild type plants, transgenic plants were exhibited significantly lower electrolyte leakage. Moreover, the transgenic plants had superior germination rates when placed on medium containing arsenic. Taken together, these overexpression results imply that mHSP23 plays an important role in salinity and arsenic stress tolerance in transgenic forage crops. This approach could be useful to develop stress-tolerant plants including forage crops.
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