• Journal of Applied Reliability
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• v.15 no.4
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• pp.262-269
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• 2015

Accelerated degradation mechanism of the heat-resistant steel for high temperature plant was analysed in terms of microstructure and hardness. In order to simulate the microstructure of the steel actually used at $540^{\circ}C$ in the field, isothermal exposure was carried out at $630^{\circ}C$ up to 4,800 hours. The artificial degradation mechanism was comparatively verified to successfully simulate degradation of the long-time used field material. For the artificially degraded specimens, databases including size and aspect ratio of carbide, chemical composition (i.e., Cr/Mo ratio) of grain boundary carbide were built up. These degradation parameters were suggested as fingerprints for PHM (i.e., prognostics health management) of power plants.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.133.2-134
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• 2003

Cedar-apple rust fungi had been collected at 36 sites throughout the country from 1984 to 2001 and deposited at the Herbarium of Korea Forest Research Institute (HKFRI). We conducted the morphological examination on the dried specimens by light and scanning electron microscopy and as results six Gymnosporangium species were identified. Three species, G. asiaticum, G. clavaritforme and G. yamadae, were previously described in Korea, while the other three species, G. cornutum, G. globosum, and G. japonicum were new to Korea. Here we present the detailed morphological descriptions, distribution, host ranges and keys to species in both aecial and telial stages of each species. Some morphological characteristics related with telial formation on trees were newly identified; witches brooms for G. asiaticum, small galls for G. yamadae and telial formations on trunk for G. japonicun Geographically G. asiaticum and G. yamadae distributed widely throughout Korea, while the others were collected only at the limited locations. Eight Juniperus species as telial hosts and fifteen Rosaceous plants as aecial hosts were confirmed to be new in Korea.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1349-1352
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• 2005

This paper is to investigate a defect for thermal barrier coating layers by acoustic emission method in 4-point bending test. The two-layer thermal barrier coating is composed of $150\mu{m}\;CoNiCrAlY\;bond\;coating\;by\;vacuum\;plasma\;spray(VPS)\;process\;and\;250\mu{m}\;ZrO_2-8wt%Y_2O_3$ ceramic coating layer by air plasma spray(APS) process on Inconel-718. The specimen prepared by cyclic thermal test(500, 1000, 2000cycle) at $1050^{\circ}C$ The AE monitoring system is composed of PICO type sensor, a wide band pre-amplifier(40dB), PC and AE DSP(16/32 PAC) board. The AE event, amplitude, Cumulative energy and count of coating specimens is evaluated according to cyclic thermal test.

• Korean Journal of Plant Taxonomy
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• v.41 no.3
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• pp.287-297
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• 2011

The objective of this study was to discuss the characteristics of the moss flora of Mt. Deogyu located on the border of the Jeonbuk and Kyungnam provinces in Korea. A total of 21 field surveys were carried out at various sites in the mountain area from August 2007 to September 2008. All the collected materials were processed into voucher specimens and were currently deposited in the herbarium at Chonbuk National University (JNU). In this study, we collected and identified 158 moss taxa, which included 156 species, 1 subsp. and 1 var. of 96 genera and 37 families. Unconfirmed taxa in this study, but previously recorded, belonged to 25 taxa, which included 13 families, 19 genera and 25 species. In addition, 183 taxa were found on Mt. Dreogyu, which belonged to 37 families, 101 genera, 1 subsp. and 1 var. The habitat of each collection was examined and the classification system of Ignatov et al. (2006) was used. New vernacular names of 6 families and 11 genera were then determined. Six species, formerly thought be only in North Korea, were shown to be present on Mt. Deogyu, which included Bucklandiella laeta, Anomobryum filiforme var. concinnatum, Herzogiella turfacea, Brachythecium rutabulum, Eurhynchium angustirete and Campylidium hispidulum.

• Korean Journal of Plant Taxonomy
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• v.41 no.1
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• pp.1-9
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• 2011

Artemisia capillaris Thunb. and A. scoparia Waldst. & Kit. are classified by their root shape, leaf size and capitulum size. However, these characteristics are not nearly as useful when attempting to identify the two species owing to the continuous variation in them. Another important taxonomic characteristics is the habit, whether it is the subshrubs or perennial herbs of A. capillaris Thunb. or the annual or biennial herbs of A. scoparia Waldst. & Kit.. All observed specimens and living individuals in Korea are subshrubs or perennial herbs, and annual or biennial examples are not found. Therefore, it is considered that A. scoparia Waldst. & Kit. is not distributed in Korea.

• Korean Journal of Plant Taxonomy
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• v.42 no.4
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• pp.324-329
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• 2012

The taxonomic identity and distribution of Artemisia integrifolia L. were reviewed based on the specimens collected from Bukchangpyeong, Onseong-gun, Hamgyeongbuk-do (in KYO), Hamrimsan, Gyeongheung-gun, Hamgyeongbuk-do (in KYO) and Hoeyang-gun Gangwon-do (in SKK). A. integrifolia is distinguishable from A. viridissima and A. subulata by middle cauline characteristics such as cauline leaves ellipticlanceolate, 1-3 pairs with coarsely serrated margins. The illustration, description and key to similar species are provided.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.42-42
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• 2018

Two unrecognized species of Sparganium of Korea were found during the our field expeditions and phylogenetic analyses of specimens deposited in the Herbarium of Korea National Arboretum (KH). S. coreanum H. $L{\acute{e}}v$. was first reported as a new species based on the specimen (Taquet, 2150) collected from Jeju Island. It has been recognized as synonym or infraspecific taxa of S. stoloniferum and S. eurycarpum or even never recognized recently. However, phylogenetic tree showed that S. coreanum is monophyletic and has sister relationship with S. eurycarpum. Furthermore, additional distribution localities were also found by herbarium survey. Morphological characteristics and distribution information of S. coreanum will be discussed. Another Sparganium species found from Mt. Daeam is occurring either as floating or emergent. Although we could not identify this species since lack of any flowers or fruits for two year surveys, phylogenetic analyses results showed that this species belong to the clade of S. glomeratum, which is distributed in high elevation lakes and marshes of Europe, Asia, and North America. Additional survey of morphology and report will be needed.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.196-206
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• 1981

We examined the imported Scolytidae and Platypodidae (Coleoptera) specimens preserved at Incheon Plant Quarantine Station. Indentified species are the following 2 subfamilies, 6 genera, 14 species in Scolytidae and 2 subfamilies, 2 genera, 11 species in Platypodidae; Scolytidae Platypodidae Ipinae Platypodinae Arixyleborus granulifer Platypus agnatus A. rugosipes P. biuncus Xyleborus posticepilosus P. curtus X. similis P. geminatus X. subcostatus P. jansoni Ips pini P. maritimus I. plastographus P. pseudocupulatus pseudocupulatus I. tridens P. shoreanus bifurcus Trypodendron lineatum P. solidus Hylesininae Diaporinae Dendroctonus adjunctus Diapus pendleburyi D. brevicois D. pusillimus D. frontalis D. ponderosae Hylurgops porosus.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.37-42
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• 2000

The boiler tubes and steam Pipes operating both at high temperature and pressure for a long period of time in a power plant are degraded by creep because of internal pressure. So, the remaining life of a component is evaluated by the creep rupture strength. Although the conventional method to evaluate the creep damage is widely used, it has some disadvantages such as requires large size specimen and long employed to evaluate the correlation between fracture toughness and evaluation time. Recently, new method so called "small lunch test' is used to evaluate degradation of creep. In this study, a conventional creep test and a small punch test are conducted using 2.25Cr-1Mo steel which is mainly used for the boiler tubes and steam pipes in power plant. The creep life, approximately 1,500 hrs, is determined by conventional method under a severe condition then specimens for a small Punch test are obtained after certain time intervals such as 1/4, 1/2 and 3/4 of final rupture time, respectively.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.969-980
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• 2017

Purpose: The purpose of this study was to estimate the lifetime, and verify the target lifetime at steady state temperature, of communication cable jackets used in nuclear power plants. Method: This study was completed according to test and analysis methods required by international standards. After measuring the residual elongation(%) of specimens at specific points in time with the accelerated degradation test, average failure time of each temperature was computed. Thus, the activation energy could be derived by applying the temperature-Arrhenius law to estimate cable jacket lifetime at steady state temperature. Results: The cable jacket lifetime was estimated as 363.8 years assuming a normal nuclear power plant operating temperature of $90^{\circ}C$. Conclusion: To ascertain stable operating conditions for a nuclear power plant, accelerated degradation tests were performed according to the Arrhenius law for components of the nuclear power plants. The lifetime was estimated from the degradation data collected during the accelerated degradation test.