• Mycobiology
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• 제35권2호
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• pp.97-99
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• 2007

Specimens collected from sweet potato plants with slime mold symptoms in fields in Daejeon, Korea were examined. Two species of Myxomycetes, Fuligo septica and Stemonitis herbatica were identified based on their morphological characteristics. This is the first report that the two species of Myxomycetes cause slime mold of sweet potato in Korea.

• Journal of Plant Biology
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• 제20권1호
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• pp.29-44
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• 1977

During a week from 6th August in 1976 to survey the fungal flora on higher fleshy fungi around Mt. Jogye 193 specimens were collected and then examined tentatively. As a result fo identification except several troublesome ones it was known that they lie within 66 genera, 110 species, 3 varieties, and 2 forms. Out of them five genera, Eutypa, Sarcosoma in Ascomycetes, and Corticium, Heimiella, Clitopilus in Basidiomycetes were confirmed as unrecorded genera to Korea. And therefrom 26 species and 1 form corresponding almost to the fourth of sum were identified as unrecorded species to Korea, among which Basidiomycetes are provided with descriptions and figures in this survey report.

• 한국자원식물학회지
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• 제33권4호
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• pp.404-416
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• 2020

생물 다양성을 유지하고 기후 변화를 조절하는 데에 중심적인 역할을 하는 열대림에는 식품 또는 의약품 개발 등 산업적으로 이용 가능한 자원 식물이 풍부하다. 이들을 활용하기 위하여 열대 및 아열대 식물의 보존 및 증식에 관한 연구가 필요한데, 국내에서는 이에 관한 연구가 미비한 실정이다. 본 연구는 국립수목원 열대식물자원연구센터가 2013년부터 미얀마 천연자원 환경보전부(Ministry Of Natural Resources and Environmental Conservation)와 미얀마 산림과학원(Forest Research Institute)과 함께 미얀마 보호지역 및 Sagging 지역 내 식물 다양성 보존을 위한 공동 현장조사, 연구 및 출판 등의 협력사업을 진행하고 있는 정보를 제공하고자 한다. 국립수목원과 미얀마 산림과학원 공동연구의 성과로 2018년 12월 미얀마 산림과학원으로부터 미얀마 유용 및 관상식물 65과 326종의 식물 생체 및 표본 등을 기증받아 국립수목원 열대식물자원연구센터에 보존과 교육 목적으로 전시 중이다. 이 기증은 미얀마에서 식물 생체를 국외로 반출한 첫번째 사례이며, 국립수목원은 2008년 독일에서 열대식물을 기증받은 사례 다음으로 두번째로 외국 정부의 공식적인 대량 식물 도입 사례다. 도입한 식물 중 Santalum album L.은 IUCN Red List of Threatened Species (IUCN, 2017)에 취약종으로 분류되어 있다. 본 연구 결과를 토대로 열대 및 아열대 식물의 생육에 적합한 인공 환경을 구명하고 국내의 실내 정원소재 및 미세먼지, 공기정화 능력을 가진 열대식물의 발굴하고 추후 열대 및 아열대 식물의 보존 및 증식 방법과 더 나아가 생물 다양성 보존 및 산업적 이용을 위한 연구에 박차를 가할 수 있을 것이다.

• 식물분류학회지
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• 제50권2호
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• pp.120-147
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• 2020

Solenostomataceae are revised for the Korean Peninsula. In total, 27 species in four genera (Metasolenostoma, Plectocolea, Protosolenostoma, Solenostoma) are recorded, the occurrence of 24 of which is confirmed. Each confirmed species is provided with an ecological overview, and a list of specimens examined and illustrations based on materials from Korea. Solenostoma jirisanense sp. nov. is described.

• 식물분류학회지
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• 제51권1호
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• pp.33-48
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• 2021

We investigated the bryophyte flora of the Gayasan Mountain National Park in Korea by conducting 18 field surveys in from April of 2009 to November of 2016 at various sites on the mountains. During the surveys, we discovered 204 taxa comprising 57 families, 106 genera, 199 species, 2 subspecies, and 3 varieties. Among these, 145 species were reported as new to the flora of Gayasan Mountain. A checklist based on a study of 903 specimens is provided. The most notable species recorded during the surveys were the rare bryophytes Hattoria yakushimensis (Horik.) R. M. Schust., Nipponolejeunea pilifera (Steph.) S. Hatt., Drepanolejeunea angustifolia (Mitt.) Grolle, Lejeuena otiana S. Hatt., Cylindrocolea recurvifolia (Steph.) Inoue and Pogonatum contortum (Menzies ex Brid.) Lesq.

• Nuclear Engineering and Technology
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• 제35권5호
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• pp.471-481
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• 2003

In order to evaluate the microstructural characteristics of irradiated fuel claddings (Zircaloy-4), two irradiated specimens having different burnups (18 GWD/MTU and 42 GWD/MTU) were prepared from the G23-M4 fuel rods, which were loaded in Kori Unit 1 for 4 fuel cycles. The oxide thickness, hydride morphology and hardness change were characterized by an optical microscope and a micro-hardness tester after preparing the irradiated specimens in the PIE (Post Irradiation Examination) facilities. The dislocation loops and the amorphous transformation of precipitates induced by the neutron irradiation in the nuclear plant were also examined by a TEM. As the burnup increased from 18 GWD/MTU to 42 GWD/MTU, the oxide thickness increased from $6.0{\mu}m\;to\;25.3{\mu}m$ and the contents of hydrogen pick-up in the Zr matrix also greatly increased. In the comparison of the hardness of the unirradiated fuel cladding, the amount of hardness increase was nearly $9.3\%\;and\;24.2\%$ for the irradiated samples of 18 and 42 GWD/MTU, respectively. Both -type dislocation loops and -type dislocation components were observed simultaneously in the irradiated specimens and the densities of the dislocation was increased by increasing the burnup. The precipitates in both the irradiated specimens were amorphously transformed by the neutron irradiation and the trend of the amorphous transformation of the precipitates was enhanced at a higher burnup.

• 대한기계학회논문집A
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• 제24권10호
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• pp.2597-2602
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• 2000

The most effective means of evaluating remaining life is through the creep testing of samples removed from the component. But sampling of large specimen from in-service component is actually impossible. So, sampling device and small-specimen creep tester have been applied. Sampling device has been devised to extract mechanically small samples by hemispherical, diamond -coated cutter from the surface of turbine rotor bores and thick-walled pipes without subsequent weld repairs requiring post weld heat treatment. A method of manufacturing small creep specimen, 2min gage diameter and 10min gage length, using electron beam welding to attach grip section, has been proven. Small-specimen creep tester has been designed to control atmosphere to prevent stress increment by oxidation during experiment. To determine whether the small specimens successfully reproduce the behavior of large specimens, creep rupture tests for small and large specimens have been performed at identical conditions. Creep rupture times based on small specimens have closely agreed within 5% error compared with that of large specimen. The errors in rupture time have decreased at longer test period. This comparison validates the procedure for fabricating and testing on small specimen. This technique offers potential as an efficient method for remaining life assessment by direct sampling from in -service high temperature components.

• Nuclear Engineering and Technology
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• 제53권9호
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• pp.3112-3121
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• 2021

One of the major factors affecting the life span of a Reactor Pressure Vessel (RPV) is the Pressurised Thermal Shock (PTS). PTS is a thermo-mechanical load on the RPV wall due to steep temperature gradients and structural load created by internal pressure of the fluid within the RPV. Safe operating life of a nuclear power plant is ensured by carrying out fracture analysis of the RPV against thermal shock. Carrying out fracture tests on RPV/large scale components is not always feasible. Hence, studies on laboratory level specimens are necessary to validate and supplement the prototype results. This paper aims to study the fracture behaviour of standard Compact Tension [C(T)] specimens, made of RPV steel 20MnMoNi55, subjected to thermal shock through experimental and numerical investigations. Fracture tests have been carried out on the C(T) specimens subjected to thermal transient load and tensile load to quantify the effect of thermal shock. Crack resistance curves are obtained from the fracture tests as per ASTM E1820 and compared with those obtained numerically using XFEM and a good agreement was found. A quantitative study on the crack tip plastic zone, computed using cohesive segment approach, from the numerical analyses justified the experimental crack initiation toughness.

• 식물분류학회지
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• 제33권4호
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• pp.455-472
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• 2003

수우(樹友) 이창복교수는 1946년 서울대학교에 부임하여 1984년 퇴임하기까지 우리 나라 식물분류학계의 기반을 다지는데 큰 기여를 하였다. 특히, 1952년부터 1984년까지 33년간 남한지역에서 약 7만여 점의 표본을 채집하여 서울대학교 농업생명과학대학 수우(樹友)표본관(SNUA)의 근간을 확립하여 체계적인 국내 최대의 표본관으로 발전시켰다. 시기별 주요 채집 활동으로 1950년대는 소지 식별을 위한 채집과 박사학위 논문연구를 위한 채집, 1960년대는 1920-1930년에 걸쳐 일본학자인 T. Nakai가 채집한 희귀식물에 대한 분포 확인차원의 채집을 시도한 시기였고, 1970년대와 1984년까지 학술조사 목적으로 특정지역의 식물상을 조사하는 채집이 주를 이루었다. 이창복교수는 참나무속과 싸리속 표본에 대한 채집과 기타 목본, 희귀식물과 관련된 수집을 직접 현장에서 식물을 확인하고 확증 표본 확보에 주력하여 현재 SNUA의 소장표본이 전국 주요 지역 식물상의 대표성을 가지는데 많은 공헌을 하였다. 특히 이창복교수의 1950년 후반에서 1960년 초반에 걸쳐 채집하여 연구한 아시아산 낙엽성 참나무속에 대한 결과는 많은 관련 연구에 근간이 되고 있다. 그러나, 불행히도 표본을 제외한 기타 채집기록이 별로 남아 있지 않아 주요 채집지와 채집 날짜 이외에 조사와 채집의 목적을 명확하게 검증하기 어렵다.

• Animal Systematics, Evolution and Diversity
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• 제36권3호
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• pp.240-250
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• 2020

Member of the genus Tobrilus Andrássy, 1959, which belongs to Tobrilidae Filipjev, 1918, are known as free-living nematodes in freshwater habitat. This genus was previously unknown from Korea. Five Tobrilus species are here reported for the first time from Korea: Tobrilus aberrans (Schneider, 1925), Tobrilus diversipapillatus (Daday, 1905), Tobrilus gracilis (Bastian, 1865), Tobrilus longus (Leidy, 1851), and Tobrilus wesenbergi (Micoletzky, 1925). Specimens were collected from sediments of the Nakdong River in Korea. Morphological characters and measurements of the specimens generally agree with the original descriptions of Tobrilus species, except for some differences that can be attributed to intraspecific variation among populations(e.g., nerve ring position [% pharynx] and reproductive length). Each species can be distinguished from other members of the genus by specific characters (e.g., cephalic setae length and position, buccal cavity and pocket shape, vulva position, degree of development of reproductive system, and tail length and shape). Here, five species in the genus Tobrilus are fully redescribed and illustrated using optical microscopy images. DNA barcode sequence information (the D2-D3 region of 28S rDNA) is also provided for molecular species identification.