• 자연과학논문집
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• 제10권1호
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• pp.33-37
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• 1998

식물의 주요 phytohormone의 하나인 cytokinin은 식물체의 줄기와 뿌리성장 그 외에도 영양의 전달이나 노화방지, 열매숙성 등 식물의 성장과 발달에 미치는 영향은 크고 다양하다. Cytokinin 생합성에 관여하는 효소를 생산하는 것으로 알려져 있으며 토양박테리아 Agrobacterium tumefaciens에 존재하는 유전자인 isopentenyl transferase (jpt)를 이용한 많은 분자생물학적 연구가 진행되어 왔는데 그 중 하나로 이 연구에서 jpt 유전자에 의한 cytokinin의 overproduction이 식물체에 성장과 발달에 어떠한 영향을 주는지 관찰하고 그 결과가 제시할 수 있는 작물의 유전 공학적 이용가능성에 대하여 알아본다.

• International Journal of Knowledge Content Development & Technology
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• 제11권1호
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• pp.49-64
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• 2021

This research paper delved into the availability and utilization of library portal services for research in university libraries in Nigeria. Two research questions and two null hypotheses were formulated to guide the study. A structured questionnaire was used for data collection. The study was carried out in Nnamdi Azikiwe Library, University of Nigeria Nsukka (UNN) and Felix Aghagbo Nwako Library, Nnamdi Azikiwe University Library (UNIZIK), Awka. A total of 70 professionals (librarians and system analysts) in these libraries supplied data for the study. Data collected was analyzed using mean and standard deviation. These were used to answer the research questions while the null hypotheses were tested using t-test statistic at 0.05 level of significance and 68 degree of freedom. Major findings showed that portal services available in the library showed that the areas of availability of library portal services in Nnamdi Azikiwe Library, U.N.N. includes Agriculture, Health Sciences, Engineering, Environmental Sciences and information about institution, Social Sciences, Arts and Humanities, Natural Sciences. In Festus Aghagbo Nwako Library, Awka, the areas of Portal Library Services include Career Development, Federal Government Programs, Environmental Sciences, Biological Sciences, Social Sciences, Arts and Humanities, Engineering, and Health Sciences. Findings on extent of utilization of portal services available in the libraries indicated that portal services are utilized to a low extent in the university libraries. Furthermore, librarians did not significantly differ in their opinions on the availability of library portal services and on the extent of utilization of library portal services in the libraries under study. It is therefore recommended that provisions should be made by the universities and library management to provide and update required portal services in addition to creating enabling environment for enhanced access and utilization of these services. The governments must make an effort to provide funds for policy implementation, necessary technology training for librarians and users, and develop general information infrastructure.

• Nuclear Engineering and Technology
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• 제51권4호
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• pp.1008-1016
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• 2019

In the SG (steam generator) of PWR (pressurized water reactor) for a nuclear plant, hundreds of U-shaped tubes are used for the heat exchanger system. They interact with primary pressurized cooling water flow, generating flow-induced vibration in the secondary flow region. A simplified U-tube model is proposed in this study to apply for experiment and its counterpart computation. Using the commercial code, ANSYS-CFX, we first verified the Moody chart, comparing the straight pipe theory with the results derived from CFD (computational fluid dynamics) analysis. Considering the virtual mass of fluid, we computed the major modes with the low natural frequencies through the comparison with impact hammer test, and then investigated the effect of pump flow in the frequency domain using FFT (fast Fourier transform) analysis of the experimental data. Using two-way fluid-structure interaction module in the CFD code, we studied the influence on mean flow rate to generate the displacement data. A feasible CFD method has been setup in this research that could be applied potentially in the field of nuclear thermal-hydraulics.

• 한국환경과학회지
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• 제15권9호
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• pp.871-880
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• 2006

Water management treatment of coastal region has been an important problem in Jeju city since the distributions of pipeline of the pumping system made a bad view in coastal region. To solve the problem, we observed the pipelines that are on the surface around the coastal region from Tapdong to Doduhang. From the observations, we found that Todong and Dodu areas were not unsightliness because the all pipelines were located in underground. However, the other areas, such area Yongdam, Handugi, Yongdam fishing village, had a serious problem for the coastal landscape view. To solve the problem, at we estimated coastal land color characteristics of Jeju city based on the observation of the pipelines. The estimated color panel shows that the green, blue and grey colors are a dominant factors of the Jeju coastal region. Based on the color panel, we proposed two methods, that is, one is a short time treatment, the other is a long time one. The short is based on the colour treatment, which is pipeline colour changing into surround natural one. The long time is the construction plan design method. Although the later method was very useful in Jeju island. However, it takes a lot of time and money. Therefore, in the situation, the short time is the better than the long time one.

• 한국비블리아학회지
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• 제6권1호
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• pp.133-160
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• 1984

The main purpose of the present study is to survey the major abstracting bulletins of national nature in Korea, to define such problem areas as lacunae, duplicates and limitation in coverage in the abstracting services currently available in Korea, and to make some suggestions for action for improving the abstracting services in the light of general principles and the tradition and situations unique to Korea. The major conclusions reached at this study are summarised as follows: (A) A new abstracting bulletin of general nature covering the whole field needs to be created in each of the following fields where no established abstracting service is available for the outcome of research and development activities in Korea. (1) Language (2) Religion (3) Art (4) Language (5) Literature (6) History (B) A new specialised abstracting bulletin needs to be created in each of the following fields of science where abstracting services limited in coverage are partially available. (a) Statistics (b) Sociology (c) political science (d) Public administration (e) Law (f) Folk lore (g) Military science (2) Pure sciences (a) Mathematics (b) Chemistry (c) Astronomy (d) Geology (e) Mineralogy (f) Life sciences (g) Botany (h) Zoology (3) Applied sciences (a) Agriculture (b) Architectural engineering (c) Mechanical engineering (d) Electrical engineering (e) Chemical engineering (f) Manufacturing industry (g) Domestic science (C) Publication of the abstracting bulletins suggested in (A) and (B) above may be ideally carried on by a qualified learned society established in the respective field. and should be financially supported by the public fund under the provisions of Art. 27 of the Research Promotion Act of 1979. (D) The current practice of adding the author's abstract and keywords to each of the records of the "Doctoral Theses in Humanities and Social Sciences" part of the" Catalogue of Doctoral and Master's Theses Submitted to the Universities in Korea" published by the National Assembly Library should be applied to all the other parts, i. e. to the parts of the "Master's Theses in Humanities and Social Sciences" and of the "Doctoral and Master's Theses in Natural Sciences': which will not only increase the Catalogue's use value but also discourage appearance of various theses abstracts of individual academic institutions such as the" Abstracts of the Doctoral and Master's Theses Submitted to Korea Advanced Institute of Science and Technology" which will in turn reduce inefficiency involved in the abstracting services at national level. (E) A general abstracting bulletin covering most part of the outcome of research and development activities in Korea other than that covered by the existing abstracts needs to be created to be temporarily. used till the abstracting journals suggested in this study will be fully available. A realistic way of having such a bulletin may be to expand the present coverage of "The Abstracts of the Reports of the Government-sponsored Projects" currently published by Korean Research Foundation.

• 자연과학논문집
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• 제8권1호
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• pp.47-51
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• 1995

알루미나와 Hydroxyapatite(HAp)의 결합을 연구하기 위하여 9 가지의 중간 유리상을 연구하였다. 그 중간상의 화학 조성은 $CaO-Al_2O_3$에서 정하였으며 CaO/$Al_2O_3$의 몰 비율은 0.5에서 3 까지 변화 시켰다. 가장 낮은 용융은 CaO/$Al_2O_3$의 몰 비율이 2이고 $1355^{\circ}C$때 나타났다. $Al_2O_3$의 양을 증가시킴에 따라 용융점은 점점 높아 졌고 많은 기공들이 발견 되었다. 단면 조직 조사에 따르면 높은 CaO양 시편에서 양호한 흡수접착을 발견할 수 있었고, 이것은 CaO/$Al_2O_3$ 비가 2보다 큰것에서 더좋은 흡수접착을 얻을 수 있음을 의미한다. 열처리후 상변태는 발견되었으나, HAp의 중요한 피크는 그대로 남아 있음을 알 수 있다.

• Biomolecules & Therapeutics
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• 제29권2호
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• pp.220-226
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• 2021

The role of particulate matter (PM) in health problems including cardiovascular diseases (CVD) and pneumonia is becoming increasingly clear. Polycyclic aromatic hydrocarbons, major components of PM, bind to aryl hydrocarbon receptor (AhRs) and promote the expression of CYP1A1 through the AhR pathway in keratinocytes. Activation of AhRs in skin cells is associated with cell differentiation in keratinocytes and inflammation, resulting in dermatological lesions. Oleanolic acid, a natural component of L. lucidum, also has anti-inflammation, anticancer, and antioxidant characteristics. Previously, we found that PM10 induced the AhR signaling pathway and autophagy process in keratinocytes. Here, we investigated the effects of oleanolic acid on PM10-induced skin aging. We observed that oleanolic acid inhibits PM10-induced CYP1A1 and decreases the increase of tumor necrosis factor-alpha and interleukin 6 induced by PM10. A supernatant derived from keratinocytes cotreated with oleanolic acid and PM10 inhibited the release of matrix metalloproteinase 1 in dermal fibroblasts. Also, the AhR-mediated autophagy disruption was recovered by oleanolic acid. Thus, oleanolic acid may be a potential treatment for addressing PM10-induced skin aging.

• 지질공학
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• 제32권4호
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• pp.627-642
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• 2022

최근까지 전 세계 에너지 수요는 화석연료(석유, 석탄, 천연가스)에 의존해왔으며, 이로 인해 지구온난화와 같은 심각한 전 지구적 환경 변화를 유발하고 있다. 에너지 관련 분야의 연구자들은 가장 유망한 에너지 운반체이자 지속 가능한 에너지 개발의 핵심 기술인 수소 에너지에 주목하고 있다. 수소 연료는 생산을 위해 사용되는 연료와 공정처리과정에 따라 그레이수소, 블루수소, 그린수소 등으로 분류된다. 지질학자들은 수소 에너지 개발을 위해 사문암화작용 또는 열수변질작용에 의한 비생물기원 수소 생산메커니즘 규명 연구를 진행하고 있다. 특히, 미국, 호주, 프랑스 등의 국가에서는 실내실험 규모의 물-암석 반응 실험을 통해 다양한 조건에서의 수소 생산성을 연구하였으나, 국내에서는 비생물기원 수소에 대한 연구가 거의 진행된 바 없는 실정이다. 이에 본 리뷰에서는 비생물기원 수소 생산을 위해 물-암석 반응 실험을 진행한 해외 연구 사례의 현황을 파악하고 향후 국내 비생물기원 수소 생산 실험을 위한 발전방향을 제시하였다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1439-1441
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• 2003

The World Health Organisation has identified ‘Fluorosis’as a serious bone disease caused by groundwater. Though the fluoride content in groundwater is a natural phenomenon, when the permissible limit of fluoride is exceeded the consequences may be fatal. This study is identified areas of high fluoride content in the Dharmapuri district of India, which is one of the major districts severely affected by fluorosis (WHO). The approach to this problem is by using GIS as a tool to locate areas of high risk. Ground Water samples collected from 35 randomly located wells (open / bore wells) in the district were analysed for fluoride content. The results were compared with the standards of WHO (World Health Organisation ), ICMR (Indian Council of Medical Research ), BIS (Bureau of Indian Standard) and PHE (Public Health Engineering) and interpolated using IDW and spline methods using Arcview GIS 3.2 a. A computer based automated information system was developed in Arcview Avenue 3.2a, so as to enable the user to visit the risk areas at his desktop and to remediate measures as and when required.

• Natural Product Sciences
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• 제11권3호
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• pp.123-126
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• 2005

Gastrodia elata Blume (Chunma) belongs to Orchidaceae, which is a perennial parasitic herbaceous plant and grows in the woods of the central provinces of China, Korea and Japan. Recently, the constituents of the tubers of this plant have been investigated by researchers who have revealed the presence of phenolic compounds including gastrodin as a major constituent, together with 4-hydroxybenzaldehyde, 4-hydroxybenzyl alcohol, parishin, 4,4-dihydroxybenzyl sulfoxide, vanillin, vanillyl alcohol, beta-sitosterol, organic acids and polysaccharides, etc. In this study, we used ultrasonicator and two kinds of enzymes for enhancement of extraction yield. We also used electronic nose for the aroma pattern analysis of Chunma extracts. The concentrations of glucose and functional constituents (gastrodin, vanillin, 4-hydroxybenzaldehyde and 4-hydroxybenzyl alcohol) were measured by biochemistry analyzer and HPLC, respectively. Therefore, we showed that the yield of extraction was increased and discomfortable odor was reduced.