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        검색결과 24

        1.
        2021.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The reactivity evaluation of copper is performed using ethylenediamine, aminoethanol, and piperidine to apply organic chelators to copper etching. It is revealed that piperidine, which is a ring-type chelator, has the lowest reactivity on copper and copper oxide and ethylenediamine, which is a chain-type chelator, has the highest reactivity via inductively coupled plasma-mass spectroscopy (ICP-MS). Furthermore, it is confirmed that the stable complex of copper-ethylenediamine can be formed during the reaction between copper and ethylenediamine using nuclear magnetic resonance (NMR) and radio-thin layer chromatography. As a final evaluation, the copper reactivity is evaluated by wet etching using each solution. Scanning electron micrographs reveal that the degree of copper reaction in ethylenediamine is stronger than that in any other chelator. This result is in good agreement with the evaluation results obtained by ICP-MS and NMR. It is concluded that ethylenediamine is a prospective etch gas for the dry etching of the copper.
        4,000원
        5.
        2019.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.
        4,000원
        12.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Grifola frondosa has been used as an herbal medicine for the treatment of cancer, diabetes mellitus and high blood pressure. In this study, functional polysaccharide was obtained from Grifola frondosa using four different extraction methods: hot water(HwFP), homogenize(HgFP), acid(AcFP), and alkali(AlFP) extraction methods. The effects of these extracts on KB and HepG2 cell lines were then examined for any anti-cancer activity. Alkaline extraction produced a yield of 0.175% and the total sugar content of the extract was 54.97%. We were able to confirm that the polysaccharide extracts from the mushroom produce an anti-cancer effect. The cytotoxicity of AlFP and AcFP against HepG2 cells were 22.86% and 28.88%, respectively, and the cytotoxicity of AlFP against the KB cell lines was 47.76% at a concentration of 1, 000 ㎍/㎖. Therefore, these results suggest that the optimum method for extracting functional polysaccharides from G. frondosa is the alkali extraction method.
        4,000원
        13.
        2006.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        중수로 원전내 여러 계통으로 부터 발생된 폐수지내에는 핵종이 다량 함유되어 있으며, Class A 및 C 폐기물로 분류되는 폐수지의 적정 처리 기술 개발을 위한 기초연구를 수행하였다. IRN-150 혼상 이온교환수지를 이용하여 비방사성 이온과 양이온의 흡착 특성 및 탈차용액을 이용한 이온의 제거 특성을 고찰하였다. IRN-150 수지의 이온의 흡착능은 이론값에 근접한 11 mg-C/g-IRN-150을 나타내었고, 양이온의 흡착 친화도를 단일성분 및 복합성분 시스템을 이용하여 분석하였다. 여러 가지 탈착용액을 이용한 폐수지로부터 이온의 제거 특성을 평가한 결과, 핵종을 전량 효과적으로 제거하기 위해서는 보다도 용액이 유리한 것으로 나타났다.
        4,300원
        14.
        2006.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        [ ] 핵종이 함유된 IRN-150 혼상 폐수지로부터 이온의 제거 및 제거된 핵종의 기체로의 전환 특성을 고찰하였다. 비방사성 이온이 흡착되어 있는 IRN-150 혼합수지로부터 이온의 탈착용액내로의 분리 및 기체로의 전환 특성을 용액의 농도 변화에 따라 평가하였으며, 탈착용액으로는 를 사용하였고, 비교 평가를 위하여 NaOH, , HCl를 이용한 기체로의 전환 특성을 분석하였다. 아울러 월성 원자력발전소에 저장중인 실제 폐수지를 이용하여 탈착용액을 이용한 폐수지내 핵종의 기체화 특성을 평가하였고, 탈착후 잔류용액내 존재하는 감마핵종을 분석하였다.
        4,000원
        16.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        Hemp (Cannabis sativa L.) is a dioecious plant, although monoecious plants are bred in some cultivars for fiber or seed production. Recently, hemp has received attention for medicinal use with some cannabinoids, including cannabidiol. Self-fertilization for breeding inbred lines is difficult because of dioeciousness and anemophily in hemp. This experiment was conducted to develop a self-fertilization method by forming female flowers and seeds from male plants of dioecious hemp. To induce the formation of female flowers on male plants, 500 ㎎ L-1 of ethephon was sprayed on plants at soon, seven and fourteen days after primordia formation. The plant ratio of female flowers formation and the number of harvested seeds were increased by ethephon treatment. Female flowers of male plants have 5 stigmas in contrast to the dual stigma of female 1plants. Male plant seeds were lighter and smaller than those from female plants. Although the germination rate was lower than that of normal seeds from female plants, the seeds from male plants germinated to grow seedlings. Thus, we suggest that hemp plants should be treated with ethephon at soon after primordia formation to induce the formation of more female flowers on the male plants.
        19.
        2007.06 KCI 등재 서비스 종료(열람 제한)
        Nitrogen (N) fertilization is essential for alleviating nutrient deficiencies of the world’s population by increasing rice production, one of the most important food crops of our time. Here we established an in vivo hydroponics rice seedling culture system to investigate the physio-biochemical and molecular responses of various rice genotypes to low nitrogen application. Yoshida’s nutrient solution (YS) was used to grow rice seedlings, and at three-week-old the seedlings manifested highly stable and reproducible symptoms, such as reduced shoot growth and length. Out of 12 genetically selected or tested genotypes, almost all (11 genotypes) showed varied degrees of growth reduction response to applied nitrogen (4 and 40 ppm N for treatment and control, respectively), but SR19663-B-B-34-3-3-3-1 showed similar growth as the control though its leaf width was smaller than the control. The leaves of a 11 representative low nitrogen-responsive genotype as BG90-2 were sampled for revealing the protein profiles between low and normal (control) nitrogen application by using two-dimensional gel electrophoresis (2-DGE) followed by staining of separated proteins with silver. Fifty differentially expressed silver stained protein spots were excised from 2-D gels and 41 proteins identified using high-throughput mass spectrometry (MS) using matrix-assisted laser desorption/ionization-time of flight-MS and nano electrospray ionization liquid chromatography tandem MS. These proteins could be assigned as major (energy metabolism, photosynthesis and oxidative stress) and minor functional categories, revealing many novel low N-responsive proteins, including those having energy/photosynthesis, and defense/stress, and iron homeostasis-related functions.
        20.
        2006.09 KCI 등재 서비스 종료(열람 제한)
        We study on the dynamic interaction with a simulated physical-biological coupled model response to nutrient reduction scenario in Jinhae Bay. According to the low relative errors, high regression coefficients of COD and DIN, and realistic distribution in comparison to the observation, our coupled model could be applicable for assessing the marine ecosystem response to nutrient input reduction in Jinhae Bay. Due to the new construction and expansion of sewage treatment plant from our government, we reduce 50% nutrient inputs near Masan Bay and sewage treatment plant. COD achieves Level Ⅱ in Korea standard of the water quality from the middle of the Masan Bay to all around Jinhae Bay except the inner Masan Bay remaining at Level Ⅲ. When our experiment reduces 50% nutrient inputs near Masan Bay and Dukdong sewage treatment plant simultaneously, COD decreases to about 0.1-1.2 mg/L (128°30’~128°40’ E , 35°05’~35°11’ N). The COD from the middle of the Masan Bay to Jinhae Bay achieves Level Ⅱ.
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