• Transactions of Materials Processing
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• v.33 no.3
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• pp.193-199
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• 2024

The friction welding characteristics of stainless steels, mainly used in energy and chemical plant industries due to its excellent corrosion resistance and high strength, was evaluated in this study. Friction welding was introduced and conducted at a rotation speed of 2,000 RPM, friction pressure of 30 MPa, burn-off length of 5 mm and upset pressure of 110 ~ 200 MPa on rod typed specimens. The grain boundary characteristics distributions such a grain size, shape, misorientation angle and kernel average misorientation of the welds were clarified by electron backscattering diffraction method. The application of friction welding on SUS304 alloy resulted in a significant refinement of the grain size in the weld zone (5.11 mm) compared to that of the base material (48.09 mm). The mechanical properties of the welds, on the other hand, appeared to be relatively low or similar to those of the base material, which were mainly caused by dislocation density in the initial material and grain refinement in the welds.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.434-466
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• 2016

In order to illustrate the flora of vascular plants distributed in the Five West Sea Islands, the authors collected vascular plants intensively in Baengnyeongdo and Socheongdo from May 2015 to August 2015. Also, voucher specimens from the previous investigations (Daecheongdo, Yeonpyeongdo and Soyeonpyeongdo) deposited at the Korean National Arboretum (KH) were re-identified. All of them were comprised of 108 families, 420 genera, 728 species, 6 subspecies, 86 varieties and 14 forms, totally 834 taxa. There were 8 endemic taxa, 19 rare taxa, 27 taxa for floristically specific to Korean floral zone except the species of their 1st and 2nd degree, and 107 naturalized taxa among the collected plants. Owing to their unusual phytogeography and low number of populations, the taxa Rosa maximowicziana Regel, Allium anisopodium Ledeb., Bistorta pacifica (Petrov ex Kom.) Kom., Scorzonera austriaca subsp. glabra (Rupr.) Lipsch. & Krasch. ex Lipsch., Iris dichotoma Pall., Amsonia elliptica (Thunb.) Roem. & Schult. were considered the most important. Based on these results, it is clear that appropriate plants to conserve the natural habitat of the Five West Sea Islands must be made immediately.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.72-80
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• 2004

Electrolytic dissolution study was carried out to evaluate the applicability of electrochemical decontamination process using a neutral salt electrolyte as a decontamination technology for the recycle or self disposal with authorization of large amount of metallic wastes contaminated with uranium compounds generated by dismantling a retired uranium conversion plant using SUS-304 and Inconel-600 specimen as the main materials of internal system components of the plant. The effects of type of neutral salt as an electrolyte, current density, and concentration of electrolyte on the dissolution of the materials were evaluated. On the basis of the results obtained through the basic inactive experiments, electrochemical decontamination tests using the specimens contaminated with uranium compounds such as $UO_2$, AUC (ammonium uranyl carbonate) and ADU (ammonium diuranate) taken from an uranium conversion plant were peformed in $Na_2SO_4$ and $NaNO_3$ solution. It was verified that the electrochemical decontamination of the dismantled metallic wastes was quite successful in $Na_2SO_4$ and $NaNO_3$ neutral salt electrolyte by reducing $\beta$ radioactivities below the level of self disposal with authorization within 10 minutes regardless of the type of contaminants and the degree of contamination.

• Korean Journal of Plant Resources
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• v.23 no.4
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• pp.274-292
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• 2010

The flora of resource plants in Middle and Northern region of Yangsan-si were investigated for 7 times from March to Sept., 2009. The study indicated that, based on voucher specimens, the flora of this area consist of 427 taxa in total; 90 families, 256 genera, 376 species, 4 subspecies, 41 varieties and 6 forms. The resource plants in this area were categorized by their use into 9 groups inclusive of 1 unidentified group. Resources plants which were investigated in this area were 167 edible, 132 pasturing, 118 medicinal, 98 stainable, 52 ornamental, 15 timber, 6 fiber, 2 industrial taxa and 101 unknown resource plants, respectively. Also, there were remarkable plants such as 16 taxa of Korean endemic plants and 36 taxa of specific plants which were designated by the Ministry of Environment. Furthermore, 22 taxa of naturalized plants were observed in this investigated area where Urban Indexn UI) was 8.9%. Although the ecological status of investigated area was comparatively well conserved, the degree of (UI) was relatively high. Based on the results of this investigation, UI has been rapidly increased due to urbanization and construction of recreation objects in this area.

• The Korean Journal of Mycology
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• v.31 no.1
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• pp.1-7
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• 2003

One hundred fifty one specimens of Beauveria spp. from 19 different locations were collected from September 1 to August 31, 2002. Most of the isolates were identified as Beauveria. bassiana. Cordyceps staphylinidaecola collected from Mt. Obong in Chunchon City covered the host with mycelia which were produced 1 to 4 stromata along with asexual spores. The size of bright yellow ununiform stromata were about 45 mm and the head about $17mm{\times}4mm$. Perithecia completely immersed were $530{\sim}550{\times}290{\sim}300{\mu}m$ in size and mainly scattered on the head. Ascospore produced in asci in the size of $400{\sim}450{\times}4{\sim}5{\mu}m$ developed thread-like secondary spores, which were directly separated into secondary conidial spores. Conidia produced at apical portion of synnemata were $2.6{\sim}3.4{\times}1.2{\sim}1.9{\mu}m$ in size. High density of mycelium was observed at $25^{\circ}C$ ranged from pH 6.5 to 8.5 after 11 days of inoculation. It took 15 to 18 days after inoculation to fully grow on the medium mixed brown rice with pupa. Mycelium developed stromata on the medium 30 days after completion of mycelial growth, where perithecia were produced in 40 days.

• Korean Journal of Plant Taxonomy
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• v.46 no.1
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• pp.65-82
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• 2016

Korean Peninsula Flora Database (KPF database), developed by T.B. Lee Herbarium of Seoul National University comprises ca. 65,000 accessions of vascular plants collected from Korean peninsula from 1850 to 1945. Among these, material from North Korea (Democratic People's Republic of Korea) is represented with ca. 33,000 accessions. The largest part of this material [ca. 4287 accessions (13%) from North Korea] originates from five Japanese and one American collectors, such as Imai, Hanjiro, Mills, Ralph Garfield, Furumi, Masatomi, Nomura, Naohiko, Saito, Tatsumoto, and Okuyama, Shunki from 1909 to 1942. These data are the third largest holding (13%) of North Korean collections after Komarov, V.L and Nakai, T. A part of scientific report about the results of these expeditions had been published before, but the present publication set it sights on giving a first overview of the itineraries and the materials collected by five collectors in North Korea. Among these, Saito has by far the largest collection with 1,730 specimens, followed by five collectors in order with 1,067, 532, 510, 368 and 370 accessions by Mills, Nomura, Okuyama, Furumi, and Imai respectively.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.383-397
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• 2011

This study was carried out to investigate the flora of the southeastern areas, including Donghae-si and Samcheok-si, of Gangwon-do. Vascular plants based on voucher specimens were summarized as 750 taxa, including 109 families, 394 genera, 642 species, 5 subspecies, 90 varieties, and 13 forms. Among the investigated 750 taxa, 17 Korean endemic, 38 rare plants and 147 specially designated plants by the Ministry of the Environment were also included. The naturalized plants were 28 taxa, and the percent of naturalized plant species was estimated as 3.7%. The life form of the investigated taxa was the H-R5-D4-e type. The usefulness of the plants of the 750 taxa listed consists of 284 taxa (37.9%) of edible plants, 232 taxa (30.9%) of medicinal plants, 124 taxa (16.5%) of pasture plants, 88 taxa (11.7%) of ornamental plants, 21 taxa (2.8%) of timber plants, 20 taxa (2.7%) of fiber plants, 7 taxa (0.9%) of miscellaneous plants and 3 taxa (0.4%) of industrial plants.

• Korean Journal of Plant Taxonomy
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• v.50 no.1
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• pp.27-55
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• 2020

We investigated the flora of Ibamsan Mt. and Baekamsan Mt., and discuss here important vascular plants found on these mountains. We created a plant list using voucher specimens collected from Ibamsan Mt. and Baekamsan deposited at CNU. There are 769 taxa in Ibamsan Mt. and Baekamsan Mt., consisting of 116 families, 403 genera, 687 species, 16 subspecies, 58 varieties, and 8 forms. Twenty-four endemic plants of Korea were found, including Coreanomecon hylomeconoides Nakai and Eranthis byunsanensis B. Y. Sun. There are 15 rare plants on Ibamsan Mt. and Baekamsan as designated by the Korea Forest Service, including Iris koreana Nakai and Chamaegastrodia shikokiana Makino & F. Maek., as well as 14 red-list plants as designated by the Ministry of the Environment, including Lycoris chinensis var. sinuolata K. Tae & S. C. Ko ex K. Tae & S. C. Ko and Cymbidium macrorhizon Lindl. In total, there are 133 taxa of floristic regional indicator plants, including four level V taxa, such as Iris koreana Nakai; ten level IV taxa, such as Lindera sericea (Siebold & Zucc.) Blume; 28 level III taxa, such as Botrychium japonicum (Prantl) Underw.; 22 level II taxa, including Hylomecon vernalis Maxim.; and 69 level I taxa, including Dryopteris erythrosora (D. C. Eaton) Kuntze. There are 37 invasive plants, including Rumex acetosella L. and Symphyotrichum pilosum (Willd.) G. L. Nesom.

• Korean Journal of Plant Taxonomy
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• v.38 no.3
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• pp.271-313
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• 2008

Though numerous Korean plants were described by $L{\acute{e}}veill{\acute{e}}$, there has been no comprehensive taxonomic examination of those taxa. The taxonomic literature has been thoroughly reexamined to determine the taxonomic status of $L{\acute{e}}veill{\acute{e}'s}$ taxa reported in serial papers of the Decades plantarum novarum using plant specimens from Korea. It was confirmed that $L{\acute{e}}veill{\acute{e}}$ described a total of 275 Korean taxa including a new genus, Hydrolirion $H. L{\acute{e}}v.$, which is now merged into the genus Blyxa Noronha ex Thou. Among 231 of the taxa described as species, 17 are currently recognized as species or varieties. The taxonomic status of 52 taxa were proved disputable as species. There were also 11 taxa which have never been a subject of discussion among Korean taxonomists.

• Korean Journal of Plant Taxonomy
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• v.50 no.4
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• pp.427-452
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• 2020

This study of vascular plants was conducted over a period of 33 days from March to October of 2018 in Byeonsanbando National Park, South Korea. Based on voucher specimens and photographs, 829 taxa in total were recorded, including 141 families, 458 genera, 748 species, 16 subspecies, 59 varieties, and 6 forma. Two endangered taxa were identified, Iris koreana Nakai and Saururus chinensis (Lour.) Baill. Five rare taxa were found, including Abeliophyllum distichum Nakai and Hypodematium glanduloso-pilosum (Tagawa) Ohwi. A total of 17 Korean endemic plants were investigated. Examples include Elsholtzia byeonsanensis M. Kim, Eranthis byunsanensis B. Y. Sun, and Lycoris flavescens M. Kim & S. T. Lee. Of floristic regional indicators (third to fifth degree), 52 taxa were identified. Naturalized plants were identified, which included 79 taxa, and 7 species of ecosystem disturbance plants, such as Ambrosia artemisiifolia L., Lactuca serriola L., and Solidago altissima L. were found. We recorded 39 taxa of the plants vulnerable to climate change.