• Food Science and Preservation
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• v.23 no.7
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• pp.977-988
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• 2016

The volatile flavor compounds in five Jeju citrus fruit varieties (Cheonhyehyang, Hallabong, Jinjihyang, Hwanggeum hyang and Redhyang) were extracted by simultaneous distillation-extraction (SDE) using solvent mixture of n-pentane and diethyl ether (1:1, v/v) and analyzed by using gas chromatography-mass spectrometry (GC-MS). The number of aroma compounds were identified with : 104 (4,939.77 mg/kg) in Cheonhyehyang, 98 (3,286.38 mg/kg) in Hallabong, 105 (3,317.56 mg/kg) in Jinjihyang, 102 (4,293.39 mg/kg) in Hwanggeumhyang, and 108 (4,049.94 mg/kg) in Redhyang. The detected main volatile compounds were; limonene, sabinene, ${\beta}$-myrcene, ${\alpha}$-pinene, ${\beta}$-pinene, linalool, 4-terpineol, ${\alpha}$-terpineol, (E)-${\beta}$-ocimene and ${\gamma}$-terpinene. Among the identified volatiles compounds, ethyl-benzene, nonanol, 1-p-menthen-9-al, (E)-isocarveol, methyl salicylate, ${\alpha}$-terpinen-7-al, perilla alcohol, and ethyl-dodecanoate were detected in Cheonhyehyang. only Furthermore, ${\beta}$-chamigrene and ${\alpha}$-selinene were in Hallabong only; 3-hydroxybutanal, (E)-2-nonenal, isoborneol, octyl acetate, (E)-2-undecenal, ${\beta}$-ylangene and guaia-6,9-diene in Jinjihyang. ${\rho}$-Cymenene, ${\beta}$-thujone, selina-4,11-diene and (E,E)-2,6-farnesol in Hwanggeumhyang only; and ${\rho}$-cymen-8-ol, bornyl acetate, carvacrol, bicycloelemene, ${\alpha}$-cubebene and 7-epi-${\alpha}$-selinene in Redhyang only. This study confirmed the differences in composition and content of volatile aroma components in five varieties of Jeju citrus fruits.

• Analytical Science and Technology
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• v.20 no.5
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• pp.383-392
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• 2007

The water soluble components were analyzed in the $PM_{2.5}$ fine particles collected at the 1100 site of Mt. Halla for the spring seasons between 1998 and 2004. The $PM_{2.5}$ mass concentrations were within $13.4{\pm}9.6{\sim}21.7{\pm}20.0{\mu}g/m^3$, and the concentrations of ionic components were in the order of nss-$SO{_4}^{2-}$ > $NH{_4}{^+}$ > $NO{_3}{^-}$ > $Ca^{2+}$ > $K^+$ > $Na^+$ > $Cl^-$ > $Mg^{2+}$, in which the concentration of nss-$SO{_4}^{2-}$($3.41{\pm}2.42{\mu}g/m^3$) was the highest. The concentrations of $NH{_4}{^+}$, $SO{_4}^{2-}$, and $NO{_3}{^-}$, the secondary pollutants, were respectively 0.60~1.50, 2.86~4.42, and $0.24{\sim}1.57{\mu}g/m^3$, which had occupied 88 % of the total ionic components, on the other hand, the concentrations of marine species were less than 5 %. The nss-$SO{_4}^{2-}$ showed the high correlation with $NH{_4}{^+}$, $K^+$, so that $NH{_4}{^+}$ and nss-$SO{_4}^{2-}$ might exist in the form of $(NH_4)_3H(SO_4)_2$ and $(NH_4)_2SO_4$ in fine particles. From the backward trajectory analysis, in case of high concentrations of $NH{_4}{^+}$ and nss-$SO{_4}^{2-}$ simultaneously, the air masses were originated and stagnated at the east region of China for a while, then moved into the atmosphere of Jeju. However, in case of $NO{_3}{^-}$ and nss-$Ca^{2+}$, the air masses originated at China and Siberia were moved into Jeju via the eastern China.

• Korean Journal of Plant Resources
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• v.15 no.3
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• pp.227-236
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• 2002

The study was performed to understand the actual vegetation by using the phytosociological method on Hypochoeris radicata community group in Jeju-Island. 1. Tracheophyte belonged to the flora species is composed of 194 taxa which comprise 47 families,136 genera, 171 species, 22 varieties and 1 forma (Naturally plants 16 families, 47 genera, 67 taxa, including 64 species, 3 varieties). 2. According to the character species, the Hypochoeris radicata community group vegetation was classified into two communities; Erigeron annuus - Conyza sumatrensis, Setaria viridis var. pachystachs -Zoysia sinica community, distributed species. 3. This species is distributed from the shore to 1,700m the sea, on Jeju Island. 4. In terms of dominance and sociability of Hypochoeris radicata, the Seohong-dong, Seogwipo city site ranked highest site and the Seongsan-ri, Namjeju-gun site ranked lowest. 5. Catapodium rigidium which is belonged Gramineae was for the Hirst time found in JeJu.

• Journal of The Korean Association of Information Education
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• v.23 no.4
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• pp.283-292
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• 2019

In this study, an unplugged education method which focuses on the data visualization training was applied to third grade students of an elementary school and analyzed its impact on enhancing their computational thinking. The analysis was conducted on 60 elementary school teachers and 124 third grade students and the unplugged education program based on the data visualization procedure was developed. The education program developed was carried out with 24 third grade students for 36 hours over six days. The effect of the program applied was analyzed through the pre-to-post comparison performed with perceptive strength test and creativity test in order to examine the enhancement in computational thinking. According to the analysis result, the unplugged education method which focuses on the data visualization training has significant effect on the 'computational perception' and 'creativity' of third grade students.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.230-236
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• 2010

Jeju Island is a volanic island which is located about 96 km south of Korean Peninsula. Volcanic ejecta, and volcaniclastic materials are widespread as soil parent materials throughout the island. Soils on the island have the characteristics of typical volcanic ash soils. This study was conducted to reclassify Jeju series based on the second edition of Soil Taxonomy and to discuss the formation of Jeju series in Jeju Island. Morphological properties of typifying pedon of Jeju series were investigated, and physico-chemical properties were analyzed according to Soil survey laboratory methods manual. The typifying pedon has dark brown (10YR 3/3) silt clay loam A horizon (0~22 cm), strong brown (7.5YR 4/6) silty clay BAt horizon (22~43 cm), brown (7.5YR 4/4) silty clay Bt1 horizon (43~80 cm), brown (7.5YR 4/6) silty clay loamBt2 horizon (80~105 cm), and brown (10YR 5/4) silty clay loam Bt3 horizon (105~150 cm). It is developed in elevated lava plain, and are derived from basalt, and pyroclastic materials. The typifying pedon contains 1.3~2.1% oxalate extractable (Al + 1/2 Fe), less than 85%phosphate retention, and higher bulk density than 0.90 Mg $m^{-3}$. That can not be classified as Andisol. But it has an argillic horizon from a depth of 22 to 150 cm, and a base saturation (sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. That can be classified as Ultisol, not as Andisol. Its has 0.9% or more organic carbon in the upper 15 cm of the argillic horizon, and can be classified as Humult. It dose not have fragipan, kandic horizon, sombric horizon, plinthite, etc. in the given depths, and key out as Haplohumult. A hoizon (0~22 cm) has a fine-earth fraction with both a bulk density of 1.0 Mg $cm^{-3}$ or less, and Al plus 1/2 Fe percentages (by ammonium oxalate) totaling more than 1.0. Thus, it keys out as Andic Haplohumult. It has 35% or more clay at the particle-size control section, and has thermic soil temperature regime. Jeju series can be classified as fine, mixed, themic family of Andic Haplohumults, not as ashy, thermic family of Typic Hapludands. In the western, and northern coastal areas which have a relatively dry climate in Jeju Island, non Andisols are widely distributed. Mean annual precipitation increase 110 mm, and mean annual temperature decrease $0.8^{\circ}C$ with increasing elevation of 100m. In the western, and northern mid-mountaineous areas Andisols, and non Andisols are distributed simultaneously. Jeju series distributed mainly in the western and northern mid-mountaineous areas are developed as Ultisols with Andic subgroup.

• Journal of The Korean Society of Grassland and Forage Science
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• v.23 no.3
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• pp.143-150
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• 2003

This study was conducted to determine the response of main growth characters, yield and chemical composition of Jeju native soybean based on the difference between phosphate rates (0, 50, 100, 150, 200, 250kg/ha) from May 11 to September 10 in 2002 in Jeju island. Days to flowering was delayed from 92 days to 97 days as the increasing of phosphate rate. Also plant height grew longer from 109cm to 124cm. The number of branches and leaves, stem diameter, root length and weight of root grew powerful as phosphate rate increased from 0 to 250kg/ha. Fresh forage yield was 26.5MT/ha in the nonphosphate plot and then was 36.9MT/ha as phosphate rate increased to 250kg/ha. And the difference between 200kg/ha and 250kg/ha in phosphate rate was not significant. Dry matter, crude protein and TDN yield increased 6.0∼7.9MT/ha, 0.9∼1.4MT/ha and 3.4∼4.9MT/ha respectively, as the increasing of phosphate rate. Also crude protein, crude fat, NFE and TDN content increased 15.5∼18.3%, 2.2∼3.3%, 42.5∼43.5%, and 56.7∼61.9% respectively. In contrast with this, crude fiber and crude ash decreased 32.1∼28.1% and 7.7∼6.8% respectively. To reach the climax of forage yield was estimated optimum phosphate rate to be 200kg/ha.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.151-158
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• 2010

This study was conducted to evaluate the feed value and growth characteristics of Sasa quelpaertensis Nakai by horse grazing in the woodland of Jeju. Crude protein (CP), NDF, ADF and minerals contents at different growth stages of Sasa quelpaertensis were analyzed. The apparent digestibilities of DM, CP, NDF and ADF were determined by total collection method using 5 Jeju horses. The yield and growth characteristics of S. quelpaertensis Nakai by horse grazing were investigated. CP contents in the currentand the previous-year-sprouted leaves of S. quelpaertenisis were $16.6{\pm}1.0%$ and $12.2{\pm}1.1%$, respectively. The digestibility of DM, CP, NDF and ADF in the current-year-sprouted leaves of S. quelpaertenisis were $47.2{\pm}1.2$, $67.8{\pm}1.0$, $47.0{\pm}1.3$ and $47.1{\pm}1.1%$, respectively. The current-year-sprouted S. quelpaertenisis tended to have high nutritional values and digestibilities compared to those of the previous-year-sprouted. The dry matter yield, plant length, leaf width and density of S. quelpaertensis Nakai were clearly decreased by horse grazing. These results show that considering the feed value and growth characteristics, the natural S. quelpaertenisis Nakai can be used as a feed source for horses.

• Journal of Embryo Transfer
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• v.16 no.2
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• pp.127-131
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• 2001

The Jeju horse has been raised for centuries in Jeju island. Recently, as the number of this indigenous horse has been dropped dramatically, this breed became Natural Monument #347 to conserve and multiply this endangered breed. To provide the basic information for AI, sexual activity and semen characteristics in Jeju horse were investigated. Jeju horse semen was collected using Missouri style artificial vagina from fertile stallion.\\`she number of mount per ejaculation was 2..3$\pm$1.8, and the ejaculation time was 27.0$\pm$12.5 seconds. The total volume and gel-free volume of semen was 47.8$\pm$26.7 ml and 42.7$\pm$27.4ml, respectively, and the concentration of sperm and the total number of spermatozoa per ejaculation was 200.7$\pm$112.9$\times$10$^{6}$ ml and 7.6$\pm$3.9$\times$10$^{9}$ ml, respectively. The percentage of motile sperm and the number of live spermatozoa per ejaculation was 75.0$\pm$18.2% and 6.1$\pm$3.4$\times$10$^{9}$ ml, respectively, and the pH of gel-free semen was 7.3$\pm$0.2. The total percentage of abnormal sperm was 31.5%, and the percentage of sperm with abnormal head, midpiece and tail was 9.5$\pm$11.7%, 7.0$\pm$4.0% and 15.0$\pm$15.0%, respectively.

• Animal Systematics, Evolution and Diversity
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• v.4 no.1
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• pp.57-66
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• 1988

한국 해산 히드라충류의 분류학적 연구의 일환으로 1973년부터 1987년까지 울릉도와 제주도에서 채집되어 이화여자대학교 자연과학대학 생물학과에 보관되어 있는 미동정 표본들을 동정 분류하였다. 그 결과 Cryptolaria pectinata (Allman, 1888), Modeeria rotunda (Quoy & Gaimard, 1817) 그리고 Thecocarpus myriophyllum orientalis Billard, 1908 가 한국 미기록종으로 밝혀졌다.

• Journal of the Speleological Society of Korea
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• v.6 no.7
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• pp.2-7
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• 1981

제주도는 한반도의 최남단에 위치하고 환태평양조선대 즉, 호상열도에서 벗어난 대륙쪽에 있는 하나의 큰 화산도로서 백두산, 울릉도와 함께 지질학적으로 매우 흥미있는 대상이다. (table omitted) 본도는 제3기말 플라이오세에서부터 제4기에 이르는 동안의 화산활동의 산물로서 형성되었으며 화산지형으로서의 지형적 특징을 잘 나타내고 있다.(중략)