• The Korean Journal of Malacology
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• v.25 no.2
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• pp.91-92
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• 2009

Two molluscan species belonging to Bivalvia (Atrina teramachii Habe) and Cephalopoda (Liocranchia reinhardti Steenstrup) were found new to the Korean malacofauna. The author report, consequently, two additional molluscan species new to the fauna with figures and remarks on slight morphological variation comparing to the original and previous descriptions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2018.04a
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• pp.160-160
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• 2018

• Proceedings of the Korean Society of Crop Science Conference
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• 1998.04a
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• pp.163-164
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• 1998

• Korean Journal of Plant Taxonomy
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• v.42 no.4
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• pp.267-274
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• 2012

To understand morphological and genetic differentiation between Euphorbia esula and E. maackii we examined 12 morphological characters and 11 isozyme loci from 14 populations of two species. Species of E. esula complex (A = 1.63, P = 44.83, $H_e$ = 0.198) in Korea maintain nearly as high as the genetic diversity reported in East Asian E. jolkinii and E. fauriei while lower than those of E. ebracteolata and E. pekinensis in Korea. Although the ranges of most morphological character variation of the two species overlap, E. esula and E. maackii were well recognized by the combination of the morphological traits, and the result of UPGMA phenogram supports the two distinct species inhibited in Korea. However, isozyme data do not support the recognition of E. esula and E. maackii. The discordance between morphological and allozyme data should be explained by the recent divergence or gene flow via introgressive hybridization between two species.

• The Korean Journal of Ecology
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• v.24 no.6
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• pp.359-364
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• 2001

Regional variations of Dictyostelid cellular slime molds were examined using molecular data. The intertranscribed spacer regions including the 5.8S ribosomal DNA of 2 species(D. purpureum, P. violaceum) of Cellular Slime Molds were sequenced and analyzed. Among 13 strains of D. purpureum and 12 strains of P. violaceum analyzed, each two strains were obtained from ATCC and the others were isolated from the forest soils in Korea. The sequences of the 5.8S ribosomal DNA were conserved among the strains of the same species, but unexpectedly highly variable among species. A high level of genetic diversity was found which was best resolved at the genus/species level as well as the family level by sequence data from the ITS 1 and ITS 2 regions. According to the sequence alignments by CLUSTAL X and the phylogeographic analyses by PAUP, 12 strains of P. violaceum were divided into three groups among which there were no difference of the morphological characteristics. Among 13 strains of D. purpureum, genetic variations were related to two morphological types, the temperate and subtropical type. There was no variation pattern according to geography in Korea, but there were some variations between Korea and other countries.

• Journal of Marine Bioscience and Biotechnology
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• v.11 no.2
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• pp.62-70
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• 2019

We investigated the variation of morphological features, density, biomass and characteristics of reproductive shoot on Zostera marina. This species was monthly monitored and collected during a year in Tongyeong (from January 2016 to December 2016). Morphological features, biomass and density showed significantly seasonal variation (p<0.001). Dimensions of Z. marina were highest in spring and early summer but lowest in winter. Biomass and leaf density of Z. marina showed highest value in May (4,700.5 g w·wt m^-2) and June (858.0 leaves m^-2) respectively and lowest value in November (515.9 g w·wt m^-2 and 312.0 leaves m^-2). Reproductive shoot was monitored from April (13℃) to June (21℃) and grew up to ca. 200 cm. Spathe length, spadix weight, numbers and weight of fruit showed significantly different on monthly. None mature flowers were monitored in April but matured flowers, fruits were founded in May and seed releasing were occurred in June.

• Development and Reproduction
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• v.16 no.1
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• pp.47-51
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• 2012

Genomic DNAs (gDNAs) were isolated from the hard clam ($Meretrix$ $lusoria$, Roding, 1798) populations of Gunsan located in the Yellow Sea of the Korean peninsula. Genetic distances among different individuals of the LSCP (light shell color population) population of the hard clam (lane 1-11), GSCP (grey shell color population) population of the hard clam (lane 12-22) and DSCP (dark shell color population) population of the hard clam (lane 23-33), respectively, were generated using Systat version 10 according to the bandsharing values and similarity matrix. The dendrogram, generated by seven reliable oligonucleotides primers, indicates 3 genetic clusters. LSCP population could be evidently discriminated with the other two populations among three populations. The longest genetic distance (0.801) was found to exist between individuals in the two populations, between individuals' no. 33 of the DSCP population and no. 06 of the LSCP population. The higher fragment sizes (>2,000 bp) are much more observed in the GSCP population. Three hard clam populations can be clearly distinguished, especially, by their morphological characters and PCR-based approach.

• Journal of Korea Foundry Society
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• v.12 no.5
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• pp.403-411
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• 1992

The growth characteristics of bainite at early stage in the fast quenched spheroidal graphite cast irons containing 0.06%Mn and 0.45%Mn during austempering process, was investigated with optical and scanning electron microscope. The following results regarding the effects of Mn and isothermal heat treatment on the morphological variation of bainitic ferrite were obtained. The morphology of bainite varies from acicular below 350$^{\circ}C$ to feather shape above 350$^{\circ}C$. The period of isothermal treatment also affects the shape of bainite at the fixed temperature. At 350$^{\circ}C$, bainite is bamboo leaf-like up to 200 secs of isothermal holding time and with further increasing time up to 300 secs, changes to a mixed structure consisting of both feather and bamboo leaf and, finally becomes all feather shape at 900 secs. The morphology of bainitic ferrite formed at early stage of 300$^{\circ}C$ isothermal treatment is similar to that of bainitic ferrite formed at 250$^{\circ}C$ or 350$^{\circ}C$ with unbranched, linear ferrite. However, bainitic ferrite divides into branches with increasing isothermal treatment, which occurs more fast at 400$^{\circ}C$ than at 350$^{\circ}C$. The difference in adding amount of Mn influences the morphology of bainitic ferrite in upper bainite. The bainitic ferrite with 0.45%Mn is observed to be more stable than that with 0.06%Mn, remaining unbranched for a longer period at the same temperature.

• Korean Journal of Plant Taxonomy
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• v.52 no.3
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• pp.144-155
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• 2022

Daphne kiusiana is an evergreen shrub with dense head-like umbels of white flowers distributed in southern Korea, Japan, China, and Taiwan. Plants in China and Taiwan are recognized as var. atrocaulis by having a dark purple stem, elliptic leaves, and persistent bracts. Recently, plants on Jejudo Island were segregated as a separate species, D. jejudoensis, given their elliptic leaves with an acuminate apex, a long hypanthium and sepals, and a glabrous hypanthium. Morphological variations of three closely related taxa, the D. kiusiana complex, were investigated across the distributional range to clarify the taxonomic delimitation of members of the complex. Twelve characters of the leaf and flower were measured from digitized herbarium specimens using the image analysis program ImageJ and were included in a morphometric analysis, the results of which indicate that the level of variation in the characters is very high. The results of a principal component analysis weakly separated D. jejudoensis from D. kiusiana according to their floral characteristics, such as a longer, glabrous hypanthium, and larger sepals. However, some individuals of D. kiusiana, particularly those from Bigeumdo Island, were included in D. jejudoensis. Recognition of D. kiusiana var. atrocaulis based on the leaf shape was not supported in the analysis, and D. jejudoensis may be recognized as a variety of D. kiusiana. Our morphometric analysis shows that digitized images of herbarium specimens could be useful and an additional method by which to investigate more diverse specimens.

• Korean Journal of Plant Taxonomy
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• v.37 no.1
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• pp.17-40
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• 2007

Patterns of morphological variation in Korean Cirsium were examined using numerical analysis, and the delimitation of taxa was evaluated. Principal components analysis of individuals of taxa using 61 morphological characters revealed the presence of two major groups. One group included C. lineare, C. vlassovianum, and C. setidens, the other contained C. pendulum, C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. nipponicum, and C. rhiniceros. Also, the result of cluster analysis recognized three sections, Onotrophe, Pseudo-eriolepis, and spanioptilon. Korean Cirsium was classified into three sections; C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. rhiniceros and C. nipponicum were belonged to sect. Onotrophe, C. setidens, C. vlassovianum and C. lineare were belonged to sect. Spanioptilon, and C. pendulum was belonged to sect. Pseudo-eriolepis. In conclusion, Korean Cirsium was classified into three sections, eight species, three varieties, and five forms.