• 비파괴검사학회지
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• 제30권2호
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• pp.110-115
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• 2010

발전용 밸브 내부의 누설은 냉각 기능 상실 및 방사선물질 방출 동 안전계통의 성능 저하와 수많은 에너지 손실 등 발전소 운전에 막대한 손상 및 사고를 초래하게 된다. 본 논문은 신뢰성 높은 진단 방법 개발을 위하여 국내 원자력발전소 2차계통의 누설 발생 또는 내부 부품의 손상이 발생할 수 있는 밸브를 대상으로 현장시험 및 모의누설실험시의 적외선열화상 측정 실험을 수행함으로써 단일계측방식의 불확실성을 제거하고 향후 누설진단에 대한 확대 적용을 도모하고자 하였다. 발전소 현장시험 및 밸브 모의누설시험시의 밸브 누설 상태에 따른 적외선열화상 이미지 측정 실험을 통하여, 적외선열화상 측정 방법은 밸브 누설 상태의 과정을 신속하고 정밀하게 측정 가능하며 향후 많은 종류의 밸브 누설진단에 활용함으로써 누설에 따른 막대한 에너지 손실 및 사고 예방의 유용한 기법으로 확대 적용이 가능할 것으로 생각된다.

• 비파괴검사학회지
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• 제32권5호
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• pp.545-550
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• 2012

원자력발전소 증기발생기 세관은 방사성물질이 외부로 누출되지 않도록 압력경계 역할을 하는 주요부품이다. 설비 운전기간이 증가함에 따라 이차측에서 유입된 슬러지가 증기발생기 2차측 유체 흐름을 따라 상부로 이동하면서 유체비등과 난류에 의해 세관 외면에 스케일이 부착되어 세관열화, 유로홈 막힘 및 열전달을 감소시키는 파울링을 유발하는 원인으로 작용한다. 따라서, 원전 운영자는 세관 외면에 쌓인 스케일의 두께를 확인하여 일정시점이 되면 화학세정 등의 정비를 수행한다. 본 논문에서는 보빈코일 와전류신호를 이용하여 세관 외면에 부착된 스케일 두께를 정량적으로 평가하는 기술을 개발하고자 스케일 시험편을 제작하여 스케일 두께와 와전류신호 진폭 간의 상관관계를 분석하였고, 이를 바탕으로 스케일의 두께를 정량적으로 평가하는 기법과 대량의 와전류 데이터를 평가할 수 있는 프로그램을 개발하였다.

• 방사선산업학회지
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• 제4권3호
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• pp.253-257
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• 2010

This experiment was carried out to investigate the effects of gamma-radiation on the rooting, growth, and color mutation in poinsettia. Using 10 poinsettia varieties ('Lollipop', 'Little Peace', 'Happy Day', 'Early Bird', 'Pixy Red', 'Happy Time', 'Heidi', 'Red Bell', 'Clara', and 'Scarlet') bred by National Institute of Horticultural and Herbal Science, 100 Gy of gamma ray was irradiated at the stage of callused cuttings. Four weeks after sticking cuttings in the rooting media, 8 cultivars showed 100% of root formation, but 'Early Bird' rooted 24.4% and even died off during the cutting propagation. After planting rooted cuttings, survival rate until flowering time varied among irradiated cultivars. While 'Pixy Red' and 'Heidi' survived about 98%, 'Clara', 'Happy Day', and 'Early Bird' survived lesser than 30%. All irradiated plants showed remarkably shorter plant height, lesser branch numbers than non-irradiated control plants. Thirty color mutants were obtained among 281 plants survived until flowering time. Nine mutants were complete color mutated branches, whereas 21 mutants were partially color mutated bracts and transitional leaves. Color patterns mutated by 100 Gy of gamma ray were divided into pink, hot pink, light red and spotted (pink spots with red main color). Pink mutants were commonly obtained. Complete color mutants were discovered from 4 plants of 'Pixy Red', 2 plants of 'Red Bell' and 3 plants of Lollipop.

• 방사선산업학회지
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• 제8권2호
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• pp.133-140
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• 2014

The sterilization of health care products is widely used to choose conventional Ethylene Oxide gas sterilization in South Korea. But the method has brought serious issues because of the toxic residual gas and global warming of $CO_2$ evacuation after the sterilization process. This study is carried out to confirm the application possibility of gamma sterilization instead of Ethylene Oxide in sanitary aid products. Four kinds of products (gauze, menstrual pad, bandage, menstrual tampon) were treated with gamma irradiation of 15 kGy, then analyzed the achievement of the sterility assurance level (SAL) $10^{-6}$ through BI test. The cytotoxicity of accelerated samples of 6 months elapse evaluated by means of colony forming rate at various concentration of the extracts. pH and UV measurements at extract concentrations were tested according to the MFDS (Ministry of food & drug safety) guideline to verify a stability & safety of product sterilized. The results revealed that the extracts did not show any significant changes in cytoxicity assay as well as pH and UV values by gamma sterilization. All extract concentration was observed high cell viability, pH and UV values were calculated within the acceptable range prescribed by the guideline. It indicates that gamma sterilization could effectively substitute for conventional sterilization such as Ethylene Oxide sterilization in the sanitary aid products.

• 방사선산업학회지
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• 제4권3호
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• pp.209-213
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• 2010

Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of $M_3$ mutants, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In $M_4$ generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

• 방사선산업학회지
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• 제8권3호
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• pp.161-168
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• 2014

Increasing utilization of radiation and RI (Radioisotope) in nuclear industry including non-power area has achieved sustainable development of radiation industry. Industries are no longer confined by a single technology or abilities but expanded for application gradually. RI-Biomics fields are one of the convergence technology that is recognized on a high-tech industry. Unlike the conventional industry, RI-Biomics field needs to various specialists to perform related task. There is no domestic training program to educate the whole process. This study aims to suggest the plan for improvement of practical skills for specialists in RI-Biomics through development of our training program. For this purpose, we have first investigated the opinion about classification scheme from experts and then analyzed the results in order to reflecting our training program. Based on analyzed results, conformity assessment was executed to organize curriculum through status of constructed device and instructor in domestic. Our training program was performed jointly with KAERI (Korea Atomic Energy Research Institute). RI-Biomics center is prepared with facilities of overall experiment to improve quality of education. Due to the fact that specialists have routine task, we organized a five-day short course to reflect temporal difficulties. We performed a trial operation to 6 participants in RI-Biomics field. Through the survey for the specialists who participated in the program, we evaluated the efficiency of our training program. The results showed that participants were satisfied with the organized curriculum and educational materials. Therefore, our program is expected to be utilized as basic research data to develop feasible program for policy development and to improve practical skills in RI-Biomics.

• 방사선산업학회지
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• 제5권3호
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• pp.203-210
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• 2011

To evaluate the ability of Bamboo (Phyllostachys nigra var. henenis Strapf) leaf extract (BL) to protect the skin from photodamage, the gross and microscopic changes in the skin of hairless mice and BL-treated mice exposed chronically to ultraviolet (UV) were examined. The skin of the UV-irradiated mice showed characteristic signs of photoaging, such as deep wrinkles across the back, increased epidermal thickeness, numerous cell infiltration, and many enlarged keratinizing cysts. BL-treated mice showed a significantly decreased wrinkling score and lack of proliferation of cysts. By the 22nd week, 88.9% (i.p. with saline) or 60.0% (topical administration with cream base) of the UV-irradiated mice developed at least one tumor. BL delayed tumor onset significantly. BL (i.p.) was also effective in reducing the occurrence of UV radiation-induced skin tumors and reduced the number of tumors per mouse. After 22 weeks of treatment, 37.5% (i.p.) of the mice treated with BL were tumor-free. Tumor multiplicity was reduced by 81.2% (i.p.) in the BL treated groups. It is noted that skin that is chronically exposed to UV is subject to photoaging and photocarcinogenesis and regular use of BL would prevent these photodamaging effects of UV.

• 한국재료학회지
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• 제31권9호
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• pp.525-531
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• 2021

Carbon-encapsulated Ni catalysts are synthesized by an electrical explosion of wires (EEW) method and applied for CO₂ methanation. We find that the presence of carbon shell on Ni nanoparticles as catalyst can positively affect CO₂ methanation reaction. Ni@5C that is produced under 5 % CH₄ partial pressure in Ar gas has highest conversions of 68 % at 350 ℃ and 70 % at 400 ℃, which are 73 and 75 % of the thermodynamic equilibrium conversion, respectively. The catalyst of Ni@10C with thicker carbon layer shows much reduced activity. The EEW-produced Ni catalysts with low specific surface area outperform Ni catalysts with high surface area synthesized by solution-based precipitation methods. Our finding in this study shows the possibility of utilizing carbon-encapsulated metal catalysts for heterogeneous catalysis reaction including CO₂ methanation. Furthermore, EEW, which is a highly promising method for massive production of metal nanoparticles, can be applied for various catalysis system, requiring scaled-up synthesis of catalysts.

• 한국육종학회지
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• 제41권4호
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• pp.510-514
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• 2009

난 시장이 확대되고 있지만 일반대중이 선호하고 있는 동양계 심비디움 난은 대부분 수입 또는 산채에 의존하여 고가로 판매되고 있고, 서양계 심비디움은 외국 품종에 대한 로열티 지불 등의 문제가 대두되고 있다. 본 연구에서는 관상가치가 있고 대량증식이 가능하여 외국산 품종을 대체할 수 있는 소형 심비디움 난을 육성하고자 하였다. 동양계 및 서양계 심 비디움의 교배종인 "동양"의 바이러스 무병주를 생장점배양에 의해 기내에서 대량증식을 하던 중, 잎무늬 돌연변이 식물체를 선발하여 고정계통을 "대국"이라 명명하였다. "대국"은 잎의 가장자리에 백색이나 노란색 줄무늬가 있는 복륜 무늬종으로 광택이 있다. "대국"의 잎 길이는 약 40 cm, 엽폭은 1.6 cm, 엽수는 4~5장으로 동양에 비교하여 잎 및 초세가 작고 단아하다. 꽃에도 복륜무늬가 있으며 개화시기는 3~5월과 9~10월 연 2회이다. 신품종 "대국"은 잎무늬 줄무늬와 초세가 단정하여 분화용 엽예품으로 관상가치가 뛰어나며, 기존 동양계 심비디움 품종에 비교하여 조직배양 및 순화가 잘되고 생육이 왕성하여 값싸게 공급 가능한 품종이다.(품종특허 등록번호: 특허 제 0478734).

• 방사성폐기물학회지
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• 제17권2호
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• pp.203-212
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• 2019

처분 부적합 폐기물이란 원전운영이나 해체 시 처리, 고화 및 포장이 요구되는 방사성폐기물 등을 일컬으며, 대표적으로 분산 특성을 갖는 입자성 방사성폐기물을 예로 들 수가 있다. 이들 폐기물에는 원전 운영과정에서 발생되는 농축폐액의 건조분말, 슬러리 및 슬러지, 향후 원전 해체과정에서 발생되는 온갖 분말 상태의 폐기물(콘크리트 파쇄물, 제염 슬러지 등), 그리고 제염이 용이치 못한 미세 크기의 방사능오염 토양 등이 있다. 입자성 폐기물을 기존의 고화방식으로 처리할 경우에는 최종 폐기물의 부피가 증가하는 단점을 갖게 되어 처분 비용의 증가 및 처분장의 수용성을 감소하는 결과를 야기할 수가 있다. 따라서 이들 문제를 해결하고자 본 연구에서는 최종 폐기물 부피의 감용화를 위해 롤 압축 기술을 이용하여 분말의 펠렛화 연구를 수행하였다.