• Bulletin of the Korean Space Science Society
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• 2009.04a
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• pp.27.1-27.1
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• 2009

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.2
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• pp.165-171
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• 2016

The attitude control, station keeping and wheel off-loading at GEO-KOMPSAT-2 are realized by thrusters firings. Thrusters 1, 2 and 3 are mounted on the same axis as the solar array, which generates the plume disturbance largely. Therefore the effect of plume disturbance should be analyzed from satellite design phase. In this paper, we described the calculation method of plume disturbance and analyzed the plume disturbance of thruster 1,2 and 3 using GEO-KOMPSAT-2 initial configuration.

• Journal of Radiation Protection and Research
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• v.11 no.2
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• pp.146-151
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• 1986

In this paper, general features and measured results of vacuum pressure on the vacuum system of 50 MeV proton KCCH-cyclotron which was installed in Korea Cancer Center Hospital are described. The vacuum system comprises five subgroups and the operating sequences are automatically controlled by EPROM-programmable controller. In normal operation, the obtained ultimate pressures of vacuum groups were $5{\times}10^{-6}mbar(I,\;II),\;2{\times}10^{-6}mbar(III),\;1.2{\times}10^{-5}mbar(IV),\;1.5{\times}10^{-6}mbar(V)$, respectively. It was confirmed that these pressures was enough to accelerate the 50 MeV-proton beam.

• Publications of The Korean Astronomical Society
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• v.22 no.4
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• pp.151-168
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• 2007

We have analyzed the comet records in the Korean history books: Samguksagi, Goryeosa, and Joseonwangjosillok. For a comparison, the Chinese and Japanese comet records collected by Kronk (1999) have also been analyzed. Power spectrum of the time series of the comet records is used to find periodic comets. Statistically significant periodicities in the power spectrum are detected at the periods of 38-40 years, about 76 years, and 300-400 years for all Korean, Chinese, and Japanese comet records. We have also calculated the past orbits of some comets that have been recently observed, to check whether or not they were recorded in the history books. We use a multistep method to numerically integrate the comet's orbital motion backward in time to 51 B.C. The gravitational force due to the Sun and the nine planets, non-gravitational force, and the relativistic effects have been considered. Comparison of comet's perihelion passage time and the position on the sky with the historical records shows that the comet Halley were recorded at every passage in both Goryeo and Joseon periods. The orbital motion of the comet Pons-Brooks has also been compared with the Korean records. For the comet Tempel-Tuttle, Swift-Tuttle, and Ikeya-Zhang, we have compared our calculation of the orbital motions with those of the previous studies.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.41-48
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• 2016

Korea has introduced Korea Emissions Trading Scheme (Korea ETS) since 2015. However, not many companies voluntarily participate in the emissions trading. The goal of this paper is to provide the way to improve the Korea ETS. This study compares the Korea ETS with EU Emissions Trading System, which has been practiced for a decade, and suggests three strategies to activate the Korea Emissions Trading Scheme. The first thing is to encourage more companies to participate in the emissions trading since the number of companies in the emissions trading in Korea is quite limited compared with that of EU. The second thing is to activate the trading of Korean Credit Unit in order to stimulate various emission reduction mechanisms. Currently, the most of the trading in the emissions market is through the Korean Allowance Unit. The third thing is to establish concrete measures to continuously improve the Korea ETS. A comprehensive evaluation of the Korea ETS is needed along with the ongoing convergence with the associated comments. The improvement of Korea ETS would be one of the most efficient ways to compete the climate change, and would also play a role to raise the status of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.673-677
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• 1997

It has been reported that E. senticosus is effective for strengthening the liver, reduction of blood sugar levels, antistress and rainforcement of stamina. However, most of the extraction from this medicinal plant is imported from foreign countries. Therefore, farmers have tried to grow it in this country even though it is difficult to propagate by seeding method. This study was carried out to improve seeding propagation using seeds in National Honam Agricultural Experinment Station from '92 to '93. The seeds of E. senticosus were immature embryo at the time of gathering seeds in autumn, and needed wet stratification treatment for after-ripening. Embryo elongated slowly for a few days after stratification treatment, and cotyledon started to develop from 40 days after treatment. There were significantly positive correlation between after-ripening period and the ratio of embryo length. Dehiscence was the highest in the ratio of embryo length of 60∼70％, and percentage of dehiscent seed after treatment for 150 days was 76.5％.

• Korean Journal of Soil Science and Fertilizer
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• v.38 no.2
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• pp.78-84
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• 2005

This study was conducted to investigate the effects of chemical treatments and electric and magnetic field treatments on germination and seedling growth of onion (Allium cepa L.). Germination ratios of the onion seed were not much different among the tested species. However, germination ratio was much higher in species of small and medium size seed than that of large one. Moisture content of the seeds was shown to be more suitable in the range of 10-15% for seed germination compare to that of 20%. The germination ratio of onion seeds was found to be increased by the chemical treatments in the order of GA<$NaNO_3$<$KNO_3$. In particular, the treatments with 0.1 and 0.2% $KNO_3$ increased the germination ratio by 13 and 15% compared to that of the non-treatment. The seeds treated with electric or magnetic field resulted in much higher germination ratio and better initial growth. Germination ratios of 86 and 88% were found in the 10 kV and 4 Gauss treatments, respectively. The length and weight of the seedlings grown for 40 days after transplanting were increased by 23-45% with 8 kV and 12 Gauss treatments compared to those of non-treatment.

• Research in Plant Disease
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• v.18 no.1
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• pp.1-9
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• 2012

A total of 20 agricultural organic materials including inorganic compounds, plant oils and plant extracts were used in the study for assessing the control efficacy on pepper diseases. Among inorganic compounds, only copper hydroxide showed inhibitory effect on both Phytophthora capsici causing Phytophthora blight and Colletotrichum acutatum causing anthracnose. Phosphorous acid inhibited the growth of P. capsici on PDA, and Sulfur/quicklime had it on that of C. acutatum. Plant essential oil, rosemary oil, and rapeseed oil among plant oils and plant extract of Japanese apricot/ginkgo nut inhibited the mycelial growth of the two pathogens. In the screening using pepper plant seedlings, the control efficacy on Phytophthora blight in 6-leaf stage of seedling was superior to that in 4-leaf stage of seedling. A protective effect on Phytophthora blight was displayed by copper hydroxide, sulfur/quicklime, water soluble calcium, phosphorous acid, plant essential oil, and cloves extract. When C. acutatum was inoculated by the non-wound method, copper hydroxide and rapeseed oil showed excellent protective activities with control values of 91.3% and 82.6%, respectively. However, copper hydroxide did not show any activity, when C. acutatum was inoculated after wounding pepper fruits. All organic materials never showed the curative effect on Phytophthora blight and anthracnose in pepper seedling assay and fruit assay.

• Korean Journal of Plant Resources
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• v.36 no.4
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• pp.402-412
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• 2023

Peucedanum japonicum Thunberg is a biennial plant that usually flowers and dies after seed setting at 2^nd year. We inspected the flowering and fertilization characteristics to establish the breeding system. The plant forms complex umbel inflorescences consisting of multiple umbellets and numerous flowers. Each flower is bisexual but allogamous because of protandry. A flower bloomed for three days with matured pollen and no stigma appearance. Inspection of pollen tube growth indicates that the pollen viability can be maintained for up to 3~7 days after first flowering (DAF). In a umbellet, flowers bloomed during 1~5 DAF and the pollen maintained viability during 3~10 DAF, and the pistil developed and maintained fertility during 8~12 DAF. Theoretically, self-pollination can be possible during 8~10 DAF in the same umbellet. Approximately 4.4% of seeds were developed by self-pollination among flowers in an enveloping solitary umbel. There is at least a 9~10 days difference for the development of an umbel with another umbel at the next branch, which indicates pollination can be permitted between different branches in an individual plant. Finally, we have established a rapid breeding method to shorten the breeding cycle to one year from two years by integrating the flowering and pollination characteristics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.239-244
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• 2003

The common errors in preoperative treatment plan for the orthognathic surgery can be occurred during cast impression, cast mounting procedure with face-bow transfer, surgical stent fabrication, and so on. One of the most common errors exists during mounting process of the model on the articulator. Accurate mounting of dental casts to articulator should be achieved by transferring the 3-dimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used for transfer this relationship to articulator, usually by relating the face-bow to a plane of reference of maxillary cast. The purpose of this study is evaluation of the accuracy of face-bow transferring of maxillary model to the articulator. The maxillary casts of thirty patients for orthognathic surgery were mounted on articulator with an face-bow instrument. The relationship of occlusal plane angle to Frankfort horizontal plane relations were compared the cephalogram with the cast-mounted articulator. As a result of this study, the significant difference between the maxillary occlusal planes angle in the cephalogram and articulator were found. The results were followed, 1. The mean occlusal plane angle in cast-mounted articulator was $13.5^{\circ}\;(SD{\pm}5.4)$. 2. The mean occlusal plane angle in cephalogram was $10.4^{\circ}\;(SD{\pm}4.3)$. 3. The mean difference of occlusal plane angle between cast-mounted articulator and cephalogram was $3.3^{\circ}\;(SD{\pm}4.6)$. According to the result, we should suggest that the occlusal plane angle to Frankfort plane in cast-mounted articulator is more steeper than that of cephalogram. And then, maxillofacial surgeon should try to get a more predictable result by suggesting the proper correction method and mounting the cast accurately.