• Korean Journal of Plant Taxonomy
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• v.49 no.1
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• pp.28-69
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• 2019

We conducted taxonomical investigations based on morphological characteristics, fruit morphology, and literature research on the tribe Potentilleae (Rosaceae) in Korea covering seven genera and 24 species. The style position on the ovary and the shape of style were useful characteristics for the classification of subtribal and generic levels in the tribe Potentilleae. The subtribe Fragariinae is characterized by subbasal or lateral style on the ovary and anthers with one theca. The subtribe Potentillinae has a subterminal style on the ovary, except for Argentina, which presents a subterminal and lateral style and anthers with two thecae. These results support the recent taxonomic recognition that i) the tribe Potentilleae consists of two subtribes, and ii) genera such as Dasiphora, Comarum, and Sibbaldianthe sometimes included in Potentilla s.l. are treated as independent genus. In the subtribe Potentillinae, Argentina, which has been treated as Potentilla, is supported as a distinct genus according to the characteristics of the subterminal and lateral style position and the ventral stipular auricles. In Fragaria, F. nipponica subsp. chejuensis, which has generally small leaves and a limited distribution only on Hallasan Mt., is supported by treatment as an endemic species. Duchesnea chrysantha is distinguished from D. indica by the characteristics of light green or yellowish green leaves, thin and somewhat membranous leaflets, and broad ovate or obovate leaflets. Each complex of P. dickinsii and P. chinensis remains unresolved with regard to controversy over the taxonomic circumscription due to their external morphological variations. Additional taxonomical research and molecular population studies are required for a more in-depth understanding of the tribe Potentilleae in Korea.

• Korean Journal of Environment and Ecology
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• v.34 no.6
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• pp.551-557
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• 2020

This study surveyed the ecological characteristics of Ladislabia taczanowskii at Songcheon Stream from March to November 2019. The species inhabited upstream, where the riverbed structure was mostly covered with boulders and cobbles. The water depth was 31-148 cm, and the stream velocity was fast at 0.94±0.23 (0.51-1.39) m/sec. The gender ratio of females to males was 1 : 0.89. The age according to the total length frequency distribution indicated that the group with 38-70 mm below in total length was one year old, the group with 70-100 mm was two years old, the group with 100-120 mm was three years old, and the group over 120-128 mm was over four years old. The total length of sexually mature fishes was 70 mm for females and 75 mm or more for males. The spawning season was from May to August, and the water temperature was 15.5-20.1℃ during the period. The prosperous spawning season was from June to July, and the water temperature was 15.8-17.2℃ during the period. The spawning ground was where the riffle began in the pool, and its bottom was formed of sand and gravel. The width was about 150 cm, and the water depth was 20 to 50 cm. The average number of eggs in the ovaries was 821 (401-1,314) per matured female, and the matured eggs were yellowish and spherical with a mean diameter of 1.62±0.02 (1.43-2.01) mm. The live foods of L. taczanowskii Cyanophyta, Chlorophyta, Bacillariophyta, Ephemeroptera, and Diptera. The feeding habit of L. taczanowskii is omnivorous, but more than 90% of the stomach content was attached algae.

• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.277-284
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• 2021

This study surveyed the ecological characteristics of Squalidus gracilis majimae at Nakdong River tributary Sinan Stream from January to December 2020. The species inhabited the riverbed that was mostly covered with gravel and sand. The water depth was 27-158 cm, and the average was rather deep at 54 cm. The stream velocity was slow at 0.41±0.19 (0.24-0.86) m/sec. The gender ratio of females to males was 1:0.73. According to the total length-frequency distribution, the age indicated that the group with less than 50 mm in total length was one year old, the group with 70-69 mm was two years old, and the group over 70 mm was three years old. The total length of sexually mature fishes was 50 mm for females and 60 mm for males. The spawning season was from June to July, and the water temperature was 20.9-23.4℃ during the period. The prosperous spawning season was July. The average number of eggs in the ovaries was 1,009 (595-1,630) per matured female, and the matured eggs were yellowish and spherical with a mean diameter of 0.78±0.08 (0.57-0.83) mm. The live foods were S. gracilis majimae Protozoa, attached algae, zooplankton, and aquatic insects. The feeding habits of S. gracilis majimae are omnivorous, but more than 80% of the stomach content was aquatic insects, Chironomidae spp. The larger the size of this species, the greater the amount and frequency of eating aquatic insects, which are animal feeds. The population that ate aquatic insects did not eat vegetable food.

• Korean Journal of Environment and Ecology
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• v.35 no.6
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• pp.601-608
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• 2021

This study surveyed the ecological characteristics of Squalidus multimacultus at Taehwa River tributary Cheokgwa Stream from January to December 2020. The species inhabited the riverbed that was mostly covered with sand. The water depth was 25-164 cm, and the average was rather deep at 68 cm. The stream velocity was slow at 0.21±0.26 (0.16-0.43) m/sec. The gender ratio of females to males was 1:0.99. The age according to the total length-frequency distribution indicated that the group with less than 50 mm (29.4 - 49 mm) in total length was one year old, the group with 50 - 69 mm was two years old, the group with 70 - 89 mm was three years old, and the group over 90 mm was four years old. The total length of sexually mature fishes was 40 mm for both males and females. The spawning season was from July to August, and the water temperatures was 23.8 - 25.4℃ during the period. The prosperous spawning season was August. The average number of eggs in the ovaries was 1,395 (648 - 2,201) per matured female, and the matured eggs were yellowish and spherical with a mean diameter of 0.67±0.24 (0.62 - 0.83) mm. The live foods were of S. multimacultus attached algae, zooplankton, aquatic insects, and Mollusca. The feeding habits of S. multimacultus were omnivorous, but more than 95% of the stomach content was plant-attached algae. The larger the size of this species, the greater the amount and frequency of eating aquatic insects, which were animal feeds. The population that ate aquatic insects did not eat vegetable food.

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.104-113
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• 2022

Plants under the genus Orostachys have been known as medicinal plants. This study deems to determine the growth and leaf color of Orostachys japonica and O. boehmeri when subjected to various LED light sources. A total of seven LED light treatments were used, i.e. red (630 nm), green (520 nm), blue (450 nm), purple (650 and 450 nm), 3000 K white (455, 600 nm), 4100 K white (455, 590 nm), and 6500 K white (450, 545 nm) LEDs. Results showed that O. japonica plants showed favorable growth under 4100 K white LED, while O. boehmeri plants had a positive growth response under white light LEDs (3000, 4100, and 6500 K). In leaf color analysis, the use of green LED showed the greatest change in CIELAB L^* and b^* values which were relatively higher compared to other treatments indicating that leaves turned yellowish. Further statistical analysis using Pearson's correlation also suggested that there is a small negative association between dry weight and b^* values of O. japonica, and a negative moderate association between plant weights (fresh and dry weight) and leaf color (L^* and b^*) and positive association between said plant weights and a^* color values of O. boehmeri. Therefore, it is recommended to cultivate O. japonica under 4100 K white LED and O. boehmeri under 3000, 4100, 6500 K white LEDs.

• Korean Journal of Materials Research
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• v.32 no.1
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• pp.9-13
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• 2022

Bullets flying with a light from the back are called "tracers". Tracers are ignited by the combustion gas of the propellant and emit bright light that allows the shooter to visually trace the flight path. Therefore, tracers mark the firing point for allies to assist shooters to hit target quickly and accurately. Conventional tracers are constructed with a mixture of an oxidizing agent, raw metal, and organic fuel. Upon ignition, the inside of the gun can be easily contaminated by the by-products, which can lead to firearm failure during long-term shooting. Moreover, there is a fire risk such as forest fires due to residual flames at impact site. Therefore, it is necessary to develop non-combustion type luminous material; however, this material must still use the heat generated from the propellant, so-called "thermoluminescence (TL)". This study aims to compare the TL emission of Dy³⁺, La³⁺ and Ho³⁺ doped MgB₄O₇ phosphors prepared by solid state reaction. The crystal structures of samples were determined by X-ray diffraction and matched with the standard pattern of MgB₄O₇. Luminescence of various doses (200 ~ 15,000 Gy) of gamma irradiated Dy³⁺, La³⁺ and Ho³⁺ (at different concentrations of 5, 10, 15 and 20 %) doped MgB₄O₇ were recorded using a luminance/color meter. The intensity of TL yellowish (CIE x = 0.401 ~ 0.486, y = 0.410 ~ 0.488) emission became stronger as the temperature increased and the total gamma-ray dose increased.

• Korean Journal of Environment and Ecology
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• v.36 no.4
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• pp.381-389
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• 2022

This study investigated the ecological characteristics of Microphysogobio yaluensis at Dugye Stream of Geum River basin from January to December 2021. The river bed structure of this species' habitat was rich in pebbles and gravel. The water depth ranged from 12 to 85 cm with an average of 23 cm, which was shallow. The stream velocity was rapid at 1.03±0.34(0.72-1.47) m/sec. The ratio of females to males was 1:0.86. The age according to the total length-frequency distribution as of summer (June, July) indicated that the group with less than 50 mm (30.4-49 mm) in total length was one year old, the group with 50-69 mm was two years old, and the group over 70-92 mm was three years old. Both male and female fish sexually matured at 50 mm long and two years old in June and July. The spawning season was from July to August, and the water temperature was between 25.8℃ and 28.2℃ during the period. The prosperous spawning season was July. The matured eggs were yellowish and spherical with a mean diameter of 0.52±0.16 (0.33-0.77) mm, and the average number of eggs found in the ovaries of mature female fish was 2,593 (1,343-4,672). As for the food of M. yaluensis, only attached algae, which grow by attaching to stones and gravel of the stream rapids, were identified. The feeding habit of M. yaluensis was reported to be herbivorous, ingesting Cyanophyta, Chlorophyta and Bacillariophya. Also, the species belonging to Bacillariophya and Chlorophyta were abundant in Dugye Stream.

• Journal of the Korean Wood Science and Technology
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• v.30 no.4
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• pp.74-79
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• 2002

Three different kinds of the crude vinegars obtained from oak(Quercus serrata), bamboo(Phyllostachys pubescens) and pine(Pinus densiflora) species were stored for approximately one year and periodically analyzed to monitor their physicochemical changes. Small changes in physical properties, such as the pH, specific gravity and amount of organic acids as well as water-soluble tar were observed in the entire course of aging period. However, the color difference of the vinegars showed a remarkable change between 7 and 10 months. In addition, these vinegars' colors changed from light yellowish orange to much deeper purple and orange during this period. The amount of organic acids and neutral compounds(dihydro-2(3H)-furanone, furfural, furfuryl alcohol, 2-hydroxy-1-methyl-1-cyclopenten-3-one, 1-hydroxy-2-propanone and methanol) in the vinegars increased or decreased periodically every three months. A good linear relationship (correlation coefficient of ca. 0.92) was obtained between the amount of organic acids and the amount of neutral compounds in such changes. However, although the amount of phenols increased or decreased periodically, its amount was decreased over the entire aging.

• Korean Journal of Ichthyology
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• v.34 no.1
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• pp.25-33
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• 2022

We investigated to elucidate the early life history of siberian stone loach, Barbatula nuda (Pisces: Nemacheilidae). Adult fish were collected using net in the Sangcheoncheon Stream, Cheongpyeong-myeon, Gapyeong-gun, Gyeonggi-do, Korea, 26th April 2020. HCG 10 IU/g was injected to female and male fish and fertilized by dry method in the laboratory. The number of eggs of B. nuda was 1,308±293 (TL: 70.64~79.24 mm), and the egg color was yellowish grey. Fertilized eggs measured 1.13±0.01 mm (n=10) in diameter and showed adhesion. The fertilized eggs started hatching after 104 hours. At the time of egg development, the 15℃ group showed an average hatching rate of 80.1±1.2% and the 20℃ group showed 61.5±6.8%, so the 15℃ group was suitable (p<0.05). Newly hatched larva an average were 3.12±0.06 mm (n=10) in total length. At 4 days after hatching, the total length was 4.89±0.09 mm (n=10), and feeding began with the mouth and anus opened, and entered to preflexion larvae stage. At 21 days after hatching, the total length was 10.98±0.40 mm (n=10), and the distal part of the notochord was bent to 45°, and entered to postflexion larvae stage At 26 days after hatching, the total length was 13.47±0.37 mm (n=10), and entered the juvenile stage.

• Journal of Mushroom
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• v.20 no.3
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• pp.107-112
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• 2022

This study was conducted to reduce the phenomenon of biased cultivation and to pursue the diversification of mushroom items. We focused on developing Sparassis latifolia varieties with a short cultivation period, stable pinheading, and a high yield. We have collected and determined the characteristics of genetic resources domestically and abroad since 2016. We bred the unique domestic variety, "Hanyeoul" and the results of this study are as follows. The optimal temperatures for mycelial growth and fruit body growth were 22~25℃ and 19~21℃, respectively. The color of the pileus was pale-yellowish white, which was similar to the color of the control variety, "Neoul". The number of days required for cultivation was 125 for bottle cultivation and 98~102 for bag cultivation, which was shorter than the number of days required for the control variety. Bottle cultivation took 39 days shorter for the new variety than the control variety. The fruiting body of the new variety was similar in size or larger than that of the control variety. The pinheading rate was more than 90% in bottle cultivation and bag cultivation, which was more stable than pinheading in the control variety. The yield was 79.1 g/bottle (1,100 cc) for bottle cultivation, which was 22.6% higher than the yield of the control variety, and 641.1~689.5 g/bag (2.6 kg) for bag cultivation, which 5.8~10.4% higher than yield of the control variety.