• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 초전도 자성체
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• pp.88-95
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• 2002

Recent development in the field of RE-Ba-Cu-O (REBCO, RE: Y or rare earth elements) bulk high-Tc superconductors (HTS) is reviewed in the present paper. After the fatal weak link problem of sintered REBCO superconductors has been overcome by melt processing, this field has been greatly advanced during last ten years. The critical current density $J_c$ at 77 K has been enhanced by introducing effective flux pinning sites into the $REBa_2Cu_3O_y$ (RE123) superconducting matrix. Large melt-textured REBCO bulk crystals have been fabricated with the TSMG(top-seeded melt growth) technique. Mechanical properties of REBCO bulks have been improved by using the Ag additive or epoxy resin. Real bulk applications such as current lead, fault current limiter, flywheel energy storage system, magnetic field source, magnetic separation system, and etc., surely come true near future.

• 한국지역사회생활과학회지
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• 제27권1호
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• pp.67-81
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• 2016

Responsible tourism has become an established area of the tourism industry. This study aims to identify the factors that influence re-participation in responsible tourism in rural Korea. On-site survey was conducted on 436 tourists by seven responsible tourism agencies in Korea. The motivation for responsible tourists was categorized into seven types: family togetherness, escape and relaxation, personal growth, social interaction, various experiences, learning, and natural experience. The estimation of a binary logistic regression model determined the characteristics of responsible tourists who are most likely to opt for re-participation in responsible tourism. Results indicated that important factors for re-participation in responsible tourism were 'age', 'educational level', 'accompany', 'length of stay', and 'motivation'. The results implied that tourists' internal and external factors are important for re-participation in responsible tourism. It is expected that this study will contribute to the market expansion of responsible tourism.

• 한국IT서비스학회지
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• 제8권1호
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• pp.99-111
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• 2009

Rapid growth of Management Information System (MIS) and evolution of software system enlarge maintenance necessity and it needs a process to implement information system service in business. This paper proposes service-oriented maintenance process of component software based on service design and implementation provided by existing processes for maintenance, MaRMI-RE and ITIL. The proposed process derives activities and tasks of the process by identifying services according to service guidelines. Service-oriented maintenance process is produced by analyzing correlation between the derived activities and tasks and MaRMI-RE's and adding the tasks to MaRMI-RE. To verify availability of the proposed service-oriented maintenance process, correlation between artifacts is proved.

• Natural Product Sciences
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• 제10권3호
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• pp.134-139
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• 2004

In this study, an immunoactivity of panaxtriol ginsenosides Re and Rg1 against infection due to Candida albicans was investigated. The ginsenosides were extracted from Red Ginseng with 85% ethanol and heat-treatment and were analyzed by HPLC on water-acetonitrile as a mobile phase. The HPLC analysis revealed that the extract contained ginsenosides Re and Rg1, which were eluted as a combined peak. By agar diffusion susceptibility, the mixture of Re and Rg1 had no growth-inhibitory activity on C. albicans yeast cells. However, in animal tests BALB/c mice given the mixture of Re and Rg1 intraperitoneally (Lp.) before intravenous (Lv.) infection with live C. albicans yeast cells had longer mean survival times (MST) than MST of control mice groups that received only buffer solution instead of Re and Rg1. In experiments 60% of the ginsenosides-treated mice survived the entire duration of the 50-day observation. The Re and Rg1 mixture induced production of nitric oxide when interacted with RAW 264.7 macrophage cell line. In addition, the mixture caused morphological change of the macrophages. These data indicate that immunostimulation by the Re and Rg1 may be responsible for the protection of mice against disseminated candidiasis.

• 한국가금학회지
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• 제34권1호
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• pp.23-29
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• 2007

본 연구는 희토(rare earth RE)와 Chlortetracycline (CTC)의 육계사료에 대한 첨가 효과를 구명하고자 실시하였다. 실험은 pen별 평균 개시시 체중이 비슷하도록 15수씩 평사로 배치하여 4처리구 4반복으로 희토와 항생제-CTC, 그리고 두 가지 혼용였을 경우의 효과를 관찰하고자 0, RE 100 ppm, CTC 200 ppm, RE100 ppm+ CTC200 ppm으로 하였다. 증체량, 사료 섭취량, 사료 요구율이 실험 기간중에 조사 되었으며, 실험 종료후 도살하여 체중에 대한 간 및 복강 지방의 비율과 장내미생물의 변화를 조사하였다. 시험 결과, RE 첨가구가 대조구보다 높은 증체량을 나타냈고(P<0.05), 사료 섭취량은 대조구에 비해 현저히 낮았으며(P<0.05), 사료 요구율도 대조구에 비해 16.08% 개선된 효과를 나타냈다(P<0.05). 생체중에 대한 복강지방의 비율도 RE 첨가구가 대조구 뿐만 아니라 기타 처리구에 비해서도 현저히 감소되었다(P<0.05). 생체중에 대한 간장 무게의 비율은 모든 처리구가 대조구와 비슷한 수준을 보였다. 장내미생물은 회장과 맹장의 미생물에 대한 관찰 결과, 희토첨가로 총 균수와 E. coli의 증식을 현저하게 억제되었으며(P<0.05), Salmonella는 수가 감소되는 경향을 보였으며, Lactobacillus의 수는 차이가 없었다. 이러한 결과 희토는 육계사료에서 항생제를 대체할 가능성을 보였으며, 희토의 첨가로 생산성이 개선되고 복강 지방 감소되는 경향을 보였으며, 장내 병원성 미생물을 억제하는 결과를 보였다.

• 한국초지조사료학회지
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• 제23권1호
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• pp.43-48
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• 2003

질소 시용에 의한 치커리의 질산염 축적과 희토처리가 질산염 강하에 미치는 영향을 검토하기 위하여 질소 시비수준에 따른 치커리 잎의 성장과 수량, 엽록소 함량, 질산엽 함량 등을 조사하였으며, 희토처리가 치커리의 생육촉진과 질산태질소 함량 감소에 미치는 영향 등을 조사한 결과를 요약하면 다음과 같다. 1. 질소 시비수준이 증가할수록 치커리 잎이 두꺼워지고 잎 크기도 커졌으며, 같은 수준의 질소 시비구에서 희토처리로 잎이 두꺼워지고 잎의 크기도 커졌다. N+2구에서 희토처리 효과가 가장 뚜렷하였다(p<0.05). 2. 질소처리 수준이 높아질수록 치커리 엽중 총 엽록소 함량과 엽록소-a 함량은 감소되었으나 엽록소-b에 대한 엽록소-a의 비율은 증가되었다. 희토처리로 총 엽록소 함량, 엽록소-a 함량 및 엽록소 a/b율이 모두 증가되었으나 통계적인 유의성은 인정되지 않았다. 3. 생체와 건물수량이 질소 시비수준 증가에 따라 증가하였으며, N+2구에서 유의성이 인정되었다(p<0.05). 희토 사용으로 생체수량은 6.7∼17.0%, 건물수량은 9.0∼10.8%증가되었다. 질소 시용증가로 건물율이 감소되었으나 희토시용은 건물율을 4.6∼5.8% 증가시켰다. 4. 질소 시용수준이 높을수록 치커리의 질산 태 질소 함량이 증가하였으나, 희토 엽면살포로 그 함량이 감소되었으며 N+2 처리구에서는 45.9%나 감소되었다. 5. 희토시용은 식물 생장에 필수적 요인인 엽록소 함량을 증가시켜 식물 생장을 촉진하고, 특히 식물체내 질산태질소 강하효과가 뚜렷하여 안전 농산물생산의 가능성을 보여 주었다.

• Nuclear Engineering and Technology
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• 제54권8호
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• pp.2801-2808
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• 2022

The synergistic effect of ZrC nanoparticle pining and Re solution in W matrix on the thermal stability of tungsten was studied by investigating the evolution of the microstructure, hardness and tensile properties after annealing in a temperature range of 1000-1700 ℃. The results of metallography, electron backscatter diffraction pattern and Vickers micro-hardness indicate that the rolled W-1wt%Re-0.5 wt% ZrC alloy has a higher recrystallization temperature (1600 ℃-1700 ℃) than that of the rolled pure W (1200 ℃), W-0.5 wt%ZrC (1300 ℃), W-0.5 wt%HfC (1400-1500 ℃) and W-K-3wt%Re alloy fabricated by the same technology. The molecular dynamics simulation results indicated that solution Re atoms in W matrix can slow down the self-diffusion of W atoms and form dragging effect to delay the growth of W grain, moreover, the diffusion coefficient decrease with increasing Re content. In addition, the ZrC nanoparticles can pin the grain boundaries and dislocations effectively, preventing the recrystallization. Therefore, synergistic effect of solid solution Re element and dispersed ZrC nanoparticles significantly increase recrystallization temperature.

• Journal of Ginseng Research
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• 제27권4호
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• pp.178-182
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• 2003

Vesicular-arbuscular mycorrhizae (VAM) fungi naturally colonise American ginseng roots and this relationship is highly beneficial to enhance plant productivity. Our goal was to determine the effect of adding two Glomus species (Glomus etuticatum, G. intraradices) on survival, photosynthetic capacity, growth, morphology and root ginsenoside content of one-year-old American ginseng plants grown in a broadleaf forest. While our study revealed that VAM inoculations significantly affected root morphology and Re ginsenoside content, the survival, photosynthetic capacity and root growth of American ginseng plants were not significantly influenced by VAM inoculations. Surface area and volume of rootlets were 16-25% higher for ginseng grown in VAM-inoculated soil compared to those grown in the control plots. Also, Re ginsenoside content was 18 ％ higher in YAM-inoculated roots compared to controls.

• 산업공학
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• 제16권1호
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• pp.103-110
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• 2003

Growth curves are widely used in forecasting the market demand. When there are only a few data points available, the estimated model parameters have a low confidence. In this case, if some expert opinions are available, it would be better for predicting future demand to adjust the model parameters using these information. This paper proposes the methodology for re-estimation of model parameters in growth curves when adjusting market potential and/or time of maximum sales. We also provide the detailed procedures for five growth curves including Bass, Logistic, Gompertz, Weibull and Cumulative Lognormal models. Applications to real data are also included.

• 한국결정성장학회지
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• 제1권1호
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• pp.5-16
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• 1991

희토류 금속 산화물(RE=Ce, Pr, Nd, Eu, Er)을 1wt% 첨가한 큐빅 $ZrO_2(10 mol% Y_2O_3)$단결정을 스컬법으로 육성하였다. 육성된 단결정의 (111) 면에서의 임피던스 분석에 의한 전기적 성질을 조사하였다. 낮은 온도($500^{\circ}C$)에서 온도와 전기전도도와의 관계를 plot하였으며 $약300-400^{\circ}C$ 사이에서 전이를 관찰하였다. 저온 (전이전)과 고온(전이후 $50^{\circ}C$까지)산소 vacancy 이동에 관한 활성화 에너지를 구하였으며 전이로 인한 활성화 에너지의 차이는 안정제로 첨가한 이트륨 이온과 희토류 dopant 그리고 산소 vacancy와의 defect complexes를 붕괴하고 이온전도에 참여하게되는 산소 vacancy 형성에 관한 활성화 에너지로 볼 수 있다. yttria가 첨가됨에 따라, 또 희토류 산화물들의 첨가에 따른 활성화 에너지를 구하였으면 이온전도기구를 논의하였다. 육성된 단결정들은 첨가된 dopantdp 기인하여 Ce은 orang-red, Pr은 golden-yellow, Nd는 lilac, Eu는 옅은 pink, Er은 pink색으로 발현하였으며 가시광선 영역에서 광흡수 결과로서 나타내었다.