• Applied Microscopy
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• 제50권
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• pp.10.1-10.6
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• 2020

Plant specimens for scanning electron microscopy (SEM) are commonly treated using standard protocols. Conventional fixatives consist of toxic chemicals such as glutaraldehyde, paraformaldehyde, and osmium tetroxide. In 1996, methanol fixation was reported as a rapid alternative to the standard protocols. If specimens are immersed in methanol for 30 s or longer and critical-point dried, they appear to be comparable in preservation quality to those treated with the chemical fixatives. A modified version that consists of methanol fixation and ethanol dehydration was effective at preserving the tissue morphology and dimensions. These solvent-based fixation and dehydration protocols are regarded as rapid and simple alternatives to standard protocols for SEM of plants.

• Computers and Concrete
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• 제17권2호
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• pp.271-280
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• 2016

This study examined the mechanical properties and adiabatic temperature rise of low-heat concrete developed based on ternary blended cement using ASTM type IV (LHC) cement, ground fly ash (GFA) and limestone powder (LSP). To enhance reactivity of fly ash, especially at an early age, the grassy membrane was scratched through the additional vibrator milling process. The targeted 28-day strength of concrete was selected to be 42 MPa for application to high-strength mass concrete including nuclear plant structures. The concrete mixes prepared were cured under the isothermal conditions of $5^{\circ}C$, $20^{\circ}C$, and $40^{\circ}C$. Most concrete specimens gained a relatively high strength exceeding 10 MPa at an early age, achieving the targeted 28-day strength. All concrete specimens had higher moduli of elasticity and rupture than the predictions using ACI 318-11 equations, regardless of the curing temperature. The peak temperature rise and the ascending rate of the adiabatic temperature curve measured from the prepared concrete mixes were lower by 12% and 32%, respectively, in average than those of the control specimen made using 80% ordinary Portland cement and 20% conventional fly ash.

• 한국안전학회지
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• 제15권1호
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• pp.28-35
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• 2000

As huge energy transfer systems like a nuclear power plant, steam power plant and petrochemical plant are operated for a long time, mechanical properties are changed by degradation. The life time of the systems can be affected by the mechanical properties. So determination of the integrity of the metallic structure is required either to en4sure that failure will not occur during the service life of the components or to evaluate the lifetime extension of the structure. An automated ball indentation(ABI) method was developed as a non-destructive technique for evaluating the integrity of such metallic components. In this paper, we would like to present the aging evaluation technique by the ABI method. The five classes of the thermally aged CF8M specimens were prepared using an artificially accelerated aging method. After holding 100, 300, 900, 1800 and 3600 hours at 43$0^{\circ}C$, the specimens were cooled down using water to room temperature respectively. The tensile test, hardness test, charpy impact test, ABI test were performed. The results of the fracture test were compared with those of ABI test and the new evaluation technique of the integrity of metallic structures was developed.

• 한국해양공학회지
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• 제13권2호통권32호
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• pp.99-107
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• 1999

Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep damage due to severe operationg conditions which are high temperature and high pressure for an extended period time. Such material degradation leads to various component failures causing serious accidents at the plants. Conventional measurement techniques such as replica method, electric resistance method, and hardness test method have such disadvantages as complex preparation and measurement procedures, too many control parameters, and therefore, low practicality and they were applied only to component surfaces with good accessibility. In this paper, artificial creep degradation test and ultrasonic measurement for their creep degraded specimens have been carried out for the purpose of evaluation for creep damage which can occur in high-temperature pipeline of fossil power plant. Absolute measuring method of quantitative ultrasonic measurement for material degradation was established, and long term creep degradationtests using life prediction formula were carried out. As a result of ultrasonic tests for crept specimens, we confirmed that the sound velocity decreased and the attenuation coefficient linearly increased in proportion to the increase of creep fractiin(${\phi}$c).

• 식물분류학회지
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• 제47권3호
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• pp.180-188
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• 2017

We evaluated the actual distribution, present status, and number of remnant individuals of Korean Sagittaria aginashi (Alismataceae) based on herbarium specimens and field surveys. We also reidentified Korean S. aginashi by analyzing sequences of the internal transcribed spacer (ITS) region. We found nine specimens of S. aginashi in herbaria from four localities housed at the Osaka Museum of Natural History (OSA) and at the Korea National Herbarium (KH). During our field research, we could not confirm the current statuses of two collection localities (Taereung and Ansan-si), though this was not the case for Ulsan-si. In addition, we found two new localities in Ulsan-si and Yangsan-si. These three remnant populations are distributed in wetlands in mountainous areas (elev. 480-740 m). With regard to the number of flowering and immature individuals in the three localities, there were <50 and <2,000, respectively, in total. ITS sequences demonstrated that the sequences of Korean and Japanese S. aginashi are uniform and distinct from other Sagittaria species. These results indicate that S. aginashi is a rare and threatened species in Korea. It should be listed as an endangered species on the Korean Red List and requires urgent protection by conservation programs, including the extensive surveys of other possible natural habitats.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.627-628
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• 2006

• 한국산학기술학회논문지
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• 제19권5호
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• pp.167-175
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• 2018

정착구의 성능 평가를 위한 대부분의 기존연구와 성능실험들이 ETAG 013 규정에 따라 실험체를 제작하고 실험을 수행한 것으로 명시해오고 있다. 하지만 실험체에 사용된 파열력 보강 철근이나 보조보강철근이 ETAG 013에서 규정된 별도의 승인이 불필요한 최소 철근량을 초과 배치하여 실험이 수행되고 있다. 따라서, 본 논문에서는 ETAG 013 규정에 대한 올바른 이해와 실험을 위해 ETAG 013 규정에서 명시하는 하중전달실험 방법과 성능기준에 대해 고찰하고, 상용화된 PT정착구 시스템을 적용하여 고강도 콘크리트, 고장력 강연선을 변수로 한 실험체를 제작하고 하중전달실험을 수행하여 원형 정착구 시스템의 성능과 보조보강철근의 상관성을 평가하였다. 실험 결과, ETAG 013 규정이 적절한 크기 및 강도의 실험체와 파열력 보강철근을 사용하지 않으면 성능을 만족하지 않는 매우 엄격한 규정임이 확인되었으며, 보조보강철근의 양을 증가 시키는 것이 아니라 실험체의 크기를 최소치수로 한정짓지 않고 규정에 따라 15%크게 적용하는 방법으로 실험을 수행하는 것이 바람직한 것으로 평가되었다.

• The Plant Pathology Journal
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• 제28권3호
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• pp.306-310
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• 2012

Populations of plant-parasitic nematodes were evaluated in soil and root samples from areas planted with passion fruit, or covered with adjacent native cerrado vegetation, in five different cropping regions of the Brazilian Federal District. From July 2007 to January 2008, twenty samples had been collected in five Rural Centers (N$\acute{u}$cleo Rural-NR) planted with passion fruit. In five sites, samples were also collected in native cerrado vegetation. Specimens of nine genera of plant-parasitic nematodes (Meloidogyne, Helicotylenchus, Rotylenchulus, Scutellonema, Pratylenchus, Paratylenchus, Hemicycliophora, Xiphinema and Criconemoides) were found in the present survey. Important nematode pathogens, such as Rotylenchulus reniformis and Meloidogyne spp. were observed in the passion fruit plantations throughout five major producing regions of the Brazilian Federal District.

• 식물분류학회지
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• 제41권2호
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• pp.156-163
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• 2011

국내에 분포하는 이팝나무의 외부형태학적 형질을 재검토하여 기존 문헌과 선행 연구와의 차이를 파악하였으며, 식물상 문헌 및 표본정보를 통해 국내 분포도를 작성하였다. 또한 잎 표피 미세구조학적 형질과 엽병의 해부학적 형질을 추가하여 간략히 기재하였다.

• 식물분류학회지
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• 제37권2호
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• pp.109-113
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• 2007

Miki에 의해 기재된 6종의 수생식물 Myriophyllum oguraense, Najas oguraensis, Najas tenuicaulis, Ruppia truncatifolia, Utricularia minor var. multispinosa and U. tenuicaulis의 기준표본을 선정하였다.