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Analysis on Suitability Light Intensity and Introduction Plan under the Indoor Lighting for the Native Evergreen Daphniphyllum macropodum (자생 상록 굴거리나무의 실내조명 하에서 적정광도 분석 및 도입방안)

  • Shin, Hyeon-Cheol;Yun, Jae-Gill;Choi, Kyoung-Ok
    • Journal of the Korean Institute of Landscape Architecture
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    • v.40 no.1
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    • pp.110-117
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    • 2012
  • This study was performed to determine light-adaptability under indoor lighting for Korean wild Daphniphyllum macropodum, and to provide an introduction plan for indoor spaces of landscape architecture. The experimental plants, Daphniphyllum macropodum were purchased from a farmhouse in Jejudo as anannualplant, and it was acclimatized in the glass-green house of the general farm of Gyeongnam National University of Science and Technology for40 days. The experiment was performed from February 15, 2010 to November 15, 2010. First, in the case of the fluorescent lamp, the growth and development condition was poor because the plants withered, or the leaves fell off under the 100lux to 500lux, but the condition under 1,000lux was good In the aspects of the number of leaves, form of the tree, photosynthesis rate in its body, and the value of sight, the best light intensity for the growth condition was under the 1,000lux. Second, in the case of the LED light, the growth and development condition was poor because the plants withered, or the leaves fell off under 100lux to 1,000lux, but the smooth growth and development was done under a more light intensity. The best intensity for the growth condition was under 2,000lux. Third, in the case of the three-wave light, the withering was serious by 1,000lux, and the growth and development was the worst amongst the four introduced lighting systems, therefore, growth under the three-wave light was incongruous. The best intensity for the growth condition was under 2,000lux. Fourth, in the case of the optical fiver, the withering did not existed under 100lux and growth was possible. The growth and development was the amongst in the four introduced lighting systems. Generally, in the more light intensity, more growth was observed, but the value of sight was higher under 1,000lux than under 2,000lux because the falling rate of leaves and the form of the tree was stable. The most effective light was under 1,000lux due to the high photosynthesis in its body. When Daphniphyllum macropodum is introduced into the indoor landscaping space considering the light, the optical fiber, fluorescent lamp, and LED light are suitable to introduce. The three-wave light is unfit. The most proper light intensity by the light source, in the case of the optical fiber, and fluorescent lamp, is 1,000lux, and, in the case of LED light, is 2,000lux. The wild Daphniphyllum macropodum is the species of tree to substitute the Schefflera actinophylla which is the introduced species, and it is expected to be use as the central tree in indoor spaces.

Feasibility of Phytoremediation for Metal-Contaminated Abandoned Mining Area (광산 인근 토양의 중금속 오염에 따른 식물정화기술의 적용성 탐색)

  • Ok, Yong-Sik;Kim, Si-Hyun;Kim, Dae-Yeon;Lee, Han-na;Lim, Soo-Kil;Kim, Jeong-Gyu
    • Korean Journal of Soil Science and Fertilizer
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    • v.36 no.5
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    • pp.323-332
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    • 2003
  • This study was carried out to provide information for the present status of soil pollution near abandoned old-zinc mining area through analysis of bound form and 0.1 N-HCl extractable concentrations of heavy metals in soils and plants. Feasibility of endemic plants for phytoremediation was evaluated by the investigation of vegetation in soils. Cd contents of the selected samples near old-zinc mining soils ranged from 0.2 to $42mg\;kg^{-1}$. Nonagricultural soils near the mining area contained great amounts of Zn, Pb, Cd, and Cu than the paddy and upland soils. Some Korean wild plants, Artemisia princeps, Artemisia montana, Erigeron canadensis, and Pueraria thunbergiana, were found to grow vigorously in the studied area. Among them, Artemisia princeps was selected as a possible phytoremediator for cleaning heavy metal contaminated soils. Artemisia princeps contained about 43 and $52mg\;kg^{-1}$ of Cd in their root and shoot as dry weight, respectively. Average contents of Cd in the rhizosphere soil, $15.68mg\;kg^{-1}$, was slightly higher than the soil-root interface soils, $14.1mg\;kg^{-1}$. Sequential extraction of Cd contaminated soils showed that average $2.4mg\;kg^{-1}$ (about 7%) of cadmium existed as exchangeable form and the average amounts increased as follows : adsorbed < organically bound < exchangeable << oxide carbonate << sulfide residual fractions. Amendment of organic by-product fertilizer in metal-contaminated soils promoted the growth of roots significantly as compared with the other treatments containing chemical fertilizer.

A Study on the Original Landscape for the Restoration and Maintenance of Buyongjeong and Juhamnu Areas in Changdeokgung Palace (창덕궁 부용정과 주합루 권역의 복원정비를 위한 원형 경관 고찰)

  • Oh, Jun-Young;Yang, Ki-Cheol
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.39 no.4
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    • pp.24-37
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    • 2021
  • This study was conducted to newly examine the original landscape of Buyongjeong(芙蓉亭) and Juhamnu(宙合樓) areas in Changdeokgung Palace(昌德宮), focusing on the modern period including the Korean Empire, and to derive useful research results for restoration and maintenance in the future. The study results can be summarized as follows. First, the artificial island in Buyongji(芙蓉池) was originally made up of a straight layer using well-trimmed processed stone. However, during the maintenance work in the 1960s and 1970s, the artificial island in Buyongji was transformed into a mixture of natural and processed stones. The handrail installed on the upper part of the artificial island in Buyongji is a unique facility that is hard to find similar cases. The handrail existed even during the Korean Empire, but was completely destroyed during the Japanese colonial period. Second, Chwibyeong(翠屛), which is currently located on the left and right of Eosumun(魚水門), is the result of a reproduction based on Northern bamboo in 2008. Although there is a view that sees the plant material of Eosumun Chwibyeong as Rigid-branch yew, the specific species is still vague. Looking at the related data and circumstances from various angles, at least in the modern era, it is highly probable that the Eosumun Chwibyeong was made of Chinese juniper like Donggwanwangmyo Shrine(東關王廟) and Guncheongung(乾淸宮) in Gyeongbokgung Palace(景福宮). Third, the backyard of Juhamnu was a space with no dense trees on top of a stone staircase-shaped structure. The stone stairway in the backyard of Juhamnu was maintained in a relatively open form, and it also functioned as a space to pass through the surrounding buildings. However, as large-scale planting work was carried out in the late 1980s, the backyard of Juhamnu was maintained in the same shape as a Terraced Flower Bed, and it was transformed into a closed space where many flowering plants were planted. Fourth, Yeonghwadang Namhaenggak(暎花堂 南行閣), which had a library function like Gyujanggak(奎章閣) and Gaeyuwa(皆有窩), was destroyed in the late 1900s and was difficult to understand in its original form. Based on modern photographs and sketch materials, this study confirmed the arrangement axis of Yeonghwadang Namhaenggak, and confirmed the shape and design features of the building. In addition, an estimated restoration map referring to 「Donggwoldo(東闕圖)」 and 「Donggwoldohyung(東闕圓形)」 was presented for the construction of basic data.

Surrogate Internet Shopping Malls: The Effects of Consumers' Perceived Risk and Product Evaluations on Country-of-Buying-Origin Image (망상대구점(网上代购店): 소비자감지풍험화산품평개대원산국형상적영향(消费者感知风险和产品评价对原产国形象的影响))

  • Lee, Hyun-Joung;Shin, So-Hyoun;Kim, Sang-Uk
    • Journal of Global Scholars of Marketing Science
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    • v.20 no.2
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    • pp.208-218
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    • 2010
  • Internet has grown fast and become one of the most important retail channels now. Various types of Internet retailers, hereafter etailers, have been introduced so far and as one type of Internet shopping mall, 'surrogate Internet shopping mall' has been prosperous and attracting consumers in the domestic market. Surrogate Internet shopping mall is a unique type of etailer that globally purchases well-known brand goods that are not imported in the market, completes delivery in the favor of individual buyers, and collects fees for these specific services. The consumers, who are usually interested in purchasing high-end and unique but not eligible brands, have difficulties to purchase these items overseas directly from the retailers or brands in other countries due to worries of payment failure and no address available for their usually domestic only delivery. In Korea, both numbers of surrogate Internet shopping malls and the magnitude of sales have been growing rapidly up to more than 430 active malls and 500 billion Korean won in 2008 since the population of consumers who want this agent shopping service is also expending. This etail business concept is originated from 'surrogate-mediated purchase' and this type of shopping agent has existed in many different forms and also in wide ranges of context level for quite a long time. As marketers face their individual buyers' representatives instead of a direct contact with them in many occasions, the impact of surrogate shoppers on consumer's decision making has been enormously important and many scholars have explored various range of agent's impact on consumer's purchase decisions in marketing and psychology field. However, not much rigorous research in the Internet commerce has been conveyed yet. Moreover, since as one of the shopping agent surrogate Internet shopping malls specifically connect overseas brands or retailers to domestic consumers, one specific character of the mall's, image of surrogate buying country, where surrogate purchases are conducted in, may play an important role to form consumers' attitude and purchase intention toward products. Furthermore it also possibly affects various dimensions of perceived risk in consumer's information processing. However, though tremendous researches have been carried exploring the effects of diverse dimensions of country of origin, related studies in Internet context has been rarely executed. There have been some studies that prove the positive impact of country of origin on consumer's evaluations as one of information clues in product manufacture descriptions, yet studies detecting the relationship between country image of surrogate buying origin and product evaluations rarely undertaken regarding this specific mall type. Thus, the authors have found it well-worth investigating in this specific retail channel and explored systematic relationships among focal constructs and elaborated their different paths. The authors have proven that country image of surrogate buying origin in the mall, where surrogate malls purchase products in and brings them from for buyers, not only has a positive effect on consumers' product evaluations including attitude and purchase intention but also has a negative effect on all three dimensions of perceived risk: product-related risk, shipping-related risk, and post-purchase risk. Specifically among all the perceived risk, product-related risk which is arisen from high uncertainty of product performance is most affected (${\beta}$= -.30) by negative country image of surrogate buying origin, and also shipping-related risk (${\beta}$= -.18) and post-purchase risk (${\beta}$= -.15) get influenced in order. Its direct effects on product attitude (${\beta}$= .10) and purchase intention (${\beta}$= .14) are also secured. Each of perceived risk dimension is proven to have a negative effect on purchase intention through product attitude as a mediator (${\beta}$= -.57: product-related risk ${\rightarrow}$ product attitude; ${\beta}$= -.24: shipping-related risk ${\rightarrow}$ product attitude; ${\beta}$= -.44: post-purchase risk ${\rightarrow}$ product attitude) as well. From the additional analysis, the paths of consumers' information processing are shown to be different based on their levels of product knowledge. While novice consumers with low level of knowledge consider only perceived risk important, expert consumers with high level of knowledge take both the country image, where surrogate services are conducted in, and perceived risk seriously to build their attitudes and formulate decisions toward products more delicately and systematically, which is in line with previous studies. This study suggests several pieces of academic and practical advice. Precisely, country image of surrogate buying origin does affect on consumer's risk perceptions and behavioral consequences. Therefore a careful selection of surrogate buying origin is recommended. Furthermore, reducing consumers' risk level is required to blossom this new type of retail business whether its consumer are novices or experts. Additionally, since consumer take different paths of elaborating information based on their knowledge levels, sophisticated marketing approaches to each group of consumers are required. For novice buyers strong devices for risk mitigation are needed to induce them to form better attitudes and for experts selections of better and advanced countries as surrogate buying origins are advised while endorsement strategy for the site might work as a reliable information clue to all consumers to mitigate the barriers to purchase goods online. The authors have also explained that the study suffers from some limitations, including generalizability. In future studies, tests of and comparisons among different types of etailers with relevant constructs are recommended to broaden the findings.

Expression and Deployment of Folk Taoism(民間道敎) in the late of Chosŏn Dynasty (조선 후기 민간도교의 발현과 전개 - 조선후기 관제신앙, 선음즐교, 무상단 -)

  • Kim, Youn-Gyeong
    • The Journal of Korean Philosophical History
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    • no.35
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    • pp.309-334
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    • 2012
  • This study attempts to study in what form Folk Taoism in the late of $Chos{\breve{o}}n$ Dynasty has existed and discuss the contents and characteristics of ideological aspects forming the foundation of private Taoism. While Guan Yu Belief(關帝信仰) in the late of $Chos{\breve{o}}n$ Dynasty is a folk belief focusing on Guan Yu, Seoneumjeulgyo(善陰?敎) and Musangdan(無相壇) are religious groups with organization. In case of Seoneumjeulgyo(善陰?敎), 'Seoneumjeul' contains perspective of Tian(天觀) of Confucianism but the ascetic practice method is to practice by reciting the name of the Buddha and the targets of a belief are Gwanje, Munchang, Buwoo. This shows the unified phenomenon of Confucianism, Buddhism, Taoism of Folk Taoism in the late of $Chos{\breve{o}}n$ Dynasty. Guan Yu Belief started at the national level led by the royal family of $Chos{\breve{o}}n$ after Japanese Invasion of Korea in 1592 was firmly settled in non-official circles. Guan Yu in the late of $Chos{\breve{o}}n$ Dynasty is expressed as the incarnation of loyalty and filial piety as well as God controlling life, death and fate. As this divine power and empowerment were spreading as scriptures among people, Guan Yu Belief was settled as a target to defeat the evil and invoke a blessing. Seoneumjeulgyo is the religious group that imitated 'Paekryunsa(白蓮社)' of Ming Qing time of China. Seoneumjeulgyo emphasized 'sympathy' with God through chanting. And it expressed writing written in the state of religious ecstasy as 'Binan(飛鸞).' Binan is also called as revelation and means to be revealed from heaven in the state united with God. Seoneumjeulgyo pursued the state united with God through a recitation of a spell and made scriptures written in the state united with God as its central doctrine. Musangdan published and spread Nanseo(鸞書,Book written by the revelation from God) and Seonso(善書) while worshipping Sam Sung Je Kun(三聖帝君). The scriptures of Folk Taoismin the late of $Chos{\breve{o}}n$ Dynasty can be roughly divided into Nanseo(鸞書) and Seonso(善書). Nanseo is a book written by the revelation from God and Seonso is a book to the standards of good deeds and encourage a person to do them such as Taishangganyingbian(太上感應篇) and Gonghwagyuk(功過格). The characteristics of Folk Taoism in the late of $Chos{\breve{o}}n$ Dynasty are as follows. First, a shrine of Guan Yu built for political reasons played a central role of Folk Taoism in the late of $Chos{\breve{o}}n$ Dynasty. Second, specific private Taoist groups such as Temple $Myory{\breve{o}}nsa$ and Musangdan appeared in the late of $Chos{\breve{o}}n$ Dynasty. These are Nandan Taoism(鸞壇道敎) that pursued the unity of God through 'sympathy' with God. Third, private Taoism of $Chos{\breve{o}}n$ was influenced by the unity of Confucianism, Buddhism, Taoism with private Taoism in the Qing Dynasty of China and religious organization form etc. Fourth, the Folk Taoism scriptures of $Chos{\breve{o}}n$ are divided into Nanseo and Seonso and Nanseo directly made in $Chos{\breve{o}}n$ is expected to be the key to reveal the characteristics of Folk Taoism.

Mother's Emotional Expressivity, Young Children's Self-regulation and Peer Competency (어머니의 정서표현성과 유아의 자기조절능력 및 또래 유능성)

  • Lee, Young Soon;Chong, Young Sook;Lee, Ki Young
    • Korean Journal of Childcare and Education
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    • v.2 no.1
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    • pp.41-63
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    • 2006
  • The purpose of this study is to investigate the differences among mother's feeling expression, children's self-regulation, and children's peer competency by socio-demographic background and provide a basic material to develop the parents' education for mother's promosing emotional environment to help development of children by understanding the correlation among mother's feeling expression children's self-regulation, and children's peer competency. The research objects were 361 of 4 to 6-year-old children and their mothers. The tool adapted by Woo Sookyong(2002) was used for Mother's emotional expressivity, and the tool of Lee Jeongran(2003) for the of self regulation and the tool of park Joohee and Lee Eunhae for the children's peer competency. Data analysis was performed with population, percentage, t-test, Cronbach $\alpha$, F-test, and co-relation of LSD posteriori test. The summary of this study are as follows; First, the more negative expressivity was shown as mother's academic career was higher and the more positive one was appeared as family income was greater according to the background of socio-demography. Female children showed the higher self-regulation, and the self-decision and action control were greater as their age was higher. Children's peer competency was higher as they were social and friendly personality. Second, there was the strong relationship among the mother's feeling expressivity, children's self-regulation and peer competency one. Mother's positive expressivity had the relationship with children's self-regulation and peer competency one while weak expressivity had it with self-decision, regulation and children's peer competency. But the strong negative heartstrings' expressivity was an improper co-relation with action control and no relation with similar age competent ability. A definitive relation existed between all low level area except the emotion of self-regulation and children's peer competency. Form the above study, it was Known that there was the relationship among the mother's feeling expressivity, children's self-regulation and peer competency. In particular, there was strong relationship between positive and weak positive expressivity, and children's self-regulation and peer competency. These results could be reflected to parents' heartstrings education by knowing the impact of a positive emotional expressivity and weak-negative one.

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Reconsideration of Acer pictum complex in Korea (한국산(韓國産) 고로쇠분류군(分類群)에 대한 재고(再考))

  • Chang, Chin-Sung
    • Korean Journal of Plant Taxonomy
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    • v.31 no.3
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    • pp.283-309
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    • 2001
  • Acer pictum complex (A. pictum Thunb. ex Murray with varieties, A. okamotoanum Nakai, A. truncatum Bunge) in eastern Asia causes frequent difficulty in identification. One hundred twenty five specimens from A. pictum complex of China, Korea and Japan and A. cappadocicum var. sinicum of China were compared to investigate patterns of intra- and interspecific variation and to evaluate a recognition of several species as well as many varieties using 22 characters for morphometric analysis. The first three PCA accounted for 59% of the total variance. No strong discontinuities existed among taxa with respect to fruit and leaf characters. Much overlap among all taxa occurred the central region of the scatter diagram. Many characters appeared to show some clinal variation with changes from east of China to Japan through Korea. This was true not only when all species as considered as a single taxon, but when characters of individual taxa were compared with geography. As one considers a path from the western part of the ranges to areas to the east, the leaves become larger in most respects and become increasingly many lobed (five to seven or nine). In general, there was a tendency toward larger nutlet with smaller wing in the area toward northeast of China (=A. truncatum), while in the east of ranges (Island Ullung-do), plants were larger with respect to characters of fruit and leaves (=A. okamotoanum). The morphological differentiation between A. okamotoanum and Japanese and Korean individuals of A. pictum was not considered sufficient to warrant recognition of either specific or varietal status and should be treated as con specific under A. pictum var. mono. Since the lectotype of Acer pictum had minute hairs uniformly on the under surface of leaves(A. pictum var. pictum), the glabrous type of A. pictum was called A. pictum var. mono as Ohahsi suggested. The univaraite analysis (the mean and maximum/minium of nutlet size and wing/nutlet length ratio) indicated geographical differentiation of northeastern populations, A. truncatum, was distinctive, but Korean individuals of A. truncatum showed an affinity between Chinese individuals of A. truncatum and Korean individuals of A. Pictum var. mono. The current results, together with qualitative character, trunk features, justify subspecific status for this taxon. The previous varieties of A. mono in Korea were indistinguishable from typical form of A. Pictum var. mono on the basis of the wing angle and nutlet size, rejecting continued recognition of these taxa as distinctive varieties. Therefore, it is recommended that only one polymorphic species of A. pictum be recognized in addition to three varieties.

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Mathematics and Society in Koryo and Chosun (고려.조선시대의 수학과 사회)

  • Joung Ji-Ho
    • The Mathematical Education
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    • v.24 no.2
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    • pp.48-73
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    • 1986
  • Though the tradition of Korean mathematics since the ancient time up to the 'Enlightenment Period' in the late 19th century had been under the influence of the Chinese mathematics, it strove to develop its own independent of Chinese. However, the fact that it couldn't succeed to form the independent Korean mathematics in spite of many chances under the reign of Kings Sejong, Youngjo, and Joungjo was mainly due to the use of Chinese characters by Koreans. Han-gul (Korean characters) invented by King Sejong had not been used widely as it was called and despised Un-mun and Koreans still used Chinese characters as the only 'true letters' (Jin-suh). The correlation between characters and culture was such that, if Koreans used Han-gul as their official letters, we may have different picture of Korean mathematics. It is quite interesting to note that the mathematics in the 'Enlightenment Period' changed rather smoothly into the Western mathematics at the time when Han-gul was used officially with Chinese characters. In Koryo, the mathematics existed only as a part of the Confucian refinement, not as the object of sincere study. The mathematics in Koryo inherited that of the Unified Shilla without any remarkable development of its own, and the mathematicians were the Inner Officials isolated from the outside world who maintained their positions as specialists amid the turbulence of political changes. They formed a kind of Guild, their posts becoming patrimony. The mathematics in Koryo significant in that they paved the way for that of Chosun through a few books of mathematics such as 'Sanhak-Kyemong', 'Yanghwi-Sanpup' and 'Sangmyung-Sanpup'. King Sejong was quite phenomenal in his policy of promotion of mathematics. King himself was deeply interested in the study, createing an atmosphere in which all the high ranking officials and scholars highly valued mathematics. The sudden development of mathematic culture was mainly due to the personality and capacity of king who took anyone with the mathematic talent into government service regardless of his birth and against the strong opposition of the conservative officials. However, King's view of mathematics never resulted in the true development of mathematics perse and he used it only as an official technique in the tradition way. Korean mathematics in King Sejong's reign was based upon both the natural philosophy in China and the unique geo-political reality of Korean peninsula. The reason why the mathematic culture failed to develop continually against those social background was that the mathematicians were not allowed to play the vital role in that culture, they being only the instrument for the personality or politics of the king. While the learned scholar class sometimes played the important role for the development of the mathematic culture, they often as not became an adamant barrier to it. As the society in Chosun needed the function of mathematics acutely, the mathematicians formed the settled class called Jung-in (Middle-Man). Jung-in was a unique class in Chosun and we can't find its equivalent in China or Japan. These Jung-in mathematician officials lacked tendency to publish their study, since their society was strictly exclusive and their knowledge was very limited. Though they were relatively low class, these mathematicians played very important role in Chosun society. In 'Sil-Hak (the Practical Learning) period' which began in the late 16th century, especially in the reigns of Kings Youngjo and Jungjo, which was called the Renaissance of Chosun, the ambitious policy for the development of science and technology called for. the rapid increase of he number of such technocrats as mathematics, astronomy and medicine. Amid these social changes, the Jung-in mathematicians inevitably became quite ambitious and proud. They tried to explore deeply into mathematics perse beyond the narrow limit of knowledge required for their office. Thus, in this period the mathematics developed rapidly, undergoing very important changes. The characteristic features of the mathematics in this period were: Jung-in mathematicians' active study an publication, the mathematic studies by the renowned scholars of Sil-Hak, joint works by these two classes, their approach to the Western mathematics and their effort to develop Korean mathematics. Toward the 'Enlightenment Period' in the late 19th century, the Western mathematics experienced great difficulty to take its roots in the Peninsula which had been under the strong influence of Confucian ideology and traditional Korean mathematic system. However, with King Kojong's ordinance in 1895, the traditional Korean mathematics influenced by Chinese disappeared from the history of Korean mathematics, as the school system was hanged into the Western style and the Western mathematics was adopted as the only mathematics to be taught at the Schools of various levels. Thus the 'Enlightenment Period' is the period in which Korean mathematics shifted from Chinese into European.

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Evaluation of Fate of $NH_4{^+}$ of Condensed Molasses Solubles(CMS) in Soil Using by $^{15}N$-Tracer Method (중질소 추적자법을 이용한 Condensed Molasses Solubles(CMS) 함유 $NH_4{^+}$의 토양 중 행동 연구)

  • Lee, Sang-Mo;Choi, Woo-Jung;Yun, Seok-In;Choi, Young-Dae;Ro, Hee-Myong;Park, Jee-Won
    • Korean Journal of Soil Science and Fertilizer
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    • v.35 no.2
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    • pp.69-76
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    • 2002
  • To study the behavior of $NH_4{^+}$ of CMS (condensed molasses solubles) in soil, a laboratory incubation experiment was conducted during a period of up to 21 days at $25^{\circ}C$. The $NH_4{^+}$ of CMS was labeled with $^{15}N$ and was applied to water-unsturated and water-saturated conditions. Soil pH was gradually decreased from 6.1 to 5.4 under unsaturated condition. However, soil pH was increased to 6.5 within 2 days under saturated condition and then was constant. The concentration of ammonium was decreased 3 times faster under unsaturated condition than under saturated condition. The concentration of nitrate was increased from 17.4 to $155.4mg\;kg^{-1}$ under unsaturated condition. But concentration of nitrate was kept with low(below $8.0mg\;kg^{-1}$) under saturated condition. During the incubation, 52.4% of $^{15}NH_4{^+}$ applied was existed in the form of $NO_3{^-}$ by nitrification under unsaturated condition. Most of applied nitrogen was immobilized within 4 days of incubation. On 21 days of the incubation the percentage of immobilized nitrogen derived from $^15NH_4{^+}$(NDFA) was 19.6% under unsaturated condition and 17.0% under saturated condition. The percentage of unaccounted N, which was lost by denitrification, was 28.4% under unsturated condition and 67.6% under saturated condition.

Evaluation of Biological Characteristics of Neutron Beam Generated from MC50 Cyclotron (MC50 싸이클로트론에서 생성되는 중성자선의 생물학적 특성의 평가)

  • Eom, Keun-Yong;Park, Hye-Jin;Huh, Soon-Nyung;Ye, Sung-Joon;Lee, Dong-Han;Park, Suk-Won;Wu, Hong-Gyun
    • Radiation Oncology Journal
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    • v.24 no.4
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    • pp.280-284
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    • 2006
  • $\underline{Purpose}$: To evaluate biological characteristics of neutron beam generated by MC50 cyclotron located in the Korea Institute of Radiological and Medical Sciences (KIRAMS). $\underline{Materials\;and\;Methods}$: The neutron beams generated with 15 mm Beryllium target hit by 35 MeV proton beam was used and dosimetry data was measured before in-vitro study. We irradiated 0, 1, 2, 3, 4 and 5 Gy of neutron beam to EMT-6 cell line and surviving fraction (SF) was measured. The SF curve was also examined at the same dose when applying lead shielding to avoid gamma ray component. In the X-ray experiment, SF curve was obtained after irradiation of 0, 2, 5, 10, and 15 Gy. $\underline{Results}$: The neutron beams have 84% of neutron and 16% of gamma component at the depth of 2 cm with the field size of $26{\times}26\;cm^2$, beam current $20\;{\mu}A$, and dose rate of 9.25 cGy/min. The SF curve from X-ray, when fitted to linear-quadratic (LQ) model, had 0.611 as ${\alpha}/{\beta}$ ratio (${\alpha}=0.0204,\;{\beta}=0.0334,\;R^2=0.999$, respectively). The SF curve from neutron beam had shoulders at low dose area and fitted well to LQ model with the value of $R^2$ exceeding 0.99 in all experiments. The mean value of alpha and beta were -0.315 (range, $-0.254{\sim}-0.360$) and 0.247 ($0.220{\sim}0.262$), respectively. The addition of lead shielding resulted in no straightening of SF curve and shoulders in low dose area still existed. The RBE of neutron beam was in range of $2.07{\sim}2.19$ with SF=0.1 and $2.21{\sim}2.35$ with SF=0.01, respectively. $\underline{Conclusion}$: The neutron beam from MC50 cyclotron has significant amount of gamma component and this may have contributed to form the shoulder of survival curve. The RBE of neutron beam generated by MC50 was about 2.2.