• Korean Journal of Soil Science and Fertilizer
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• v.25 no.1
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• pp.16-25
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• 1992

A pot experiment was conducted to understand effect of soil temperaute on soybean shoot and root growth, and its relations to nutrient uptake including phosporus and potassium. Pregerminated soybean seedlings, Paldal cultivar, were planted for 43 days on the pots with Ihyeon silt loam and Samgag sandy loam in the temperature controled water baths at 17, 25 and $32^{\circ}C$. Shoot and root samples were taken at four times and analyzed. Shoot and root dry matter weights were heavier as higher soil temperaure. The root dry matter increased faster than shoot at earlier period. Shoot dry matter weights grown at 17 and $25^{\circ}C$ showed little difference between two soils, however, those grown in silt loam at $32^{\circ}C$ were heavier than sandy loam. The total lengths of roots were longer as higher soil temperature, and longer in silt loam than sandy loam. The roots grown in sandy loam at low temperature were thicker than the roots grown in silt loam at high temperature. The uptakes of phosphorus and potassium were higher as higher tempeature with same trend with dry matter. The uptake rate of unit root surface area was higher in sandy loam soil than silt loam. The uptake rates showed strong dependence on soil temperature as well as dependence of water uptake rate. Based on Dalton and Gardner model, at high temperature the dependence trend of phosphorus and potassium on soil temperature showed with active uptake model, while at low temperature the dependence showed without active uptake model.

• Journal of Korean Society of Forest Science
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• v.104 no.3
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• pp.411-420
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• 2015

This study examined methods for stand density control by using shape ratio (tree height/DBH) and its application for effective management of Pinus thunbergii coastal disaster prevention forests. We analyzed the present conditions (height, DBH, and density) of P. thunbergii coastal disaster prevention forests at 123 study sites on Jeju Island and west, south, and east coasts of South Korea and compared them with results from previous studies. The average shape ratio for P. thunbergii showed positive correlations with stand density and was significantly higher on the west coast (66.32) than on the south (49.57) and east (48.19) coasts and Jeju Island (48.29). Stands with shape ratio higher than 70 accounted for 50% of the total study sites on the west coast, indicating a decrease in their disaster prevention function compared to that of other previous studies. The stand density in most coastal areas, except the east coast, was significantly higher than the standards recommended by the Korea Forest Service and the Forestry and Forest Products Research Institute of Japan, indicating the need for stand density control. According to the growth estimation equation for P. thunbergii in the coastal area of South Korea, density control is required for young stands less than 14 years old, which show drastic increase in the shape ratio, to conserve their disaster prevention function. Particularly, the first thinning of P. thunbergii forests should be implemented before the stand age of 8 years that a shape ratio exceeds 70. For disaster-prone young stands (${\leq}20cm$ DBH) of P. thunbergii, the stand density was higher in the standard of Japan considering shape ratio than in that of Korea aiming timber production. Hence, the standard guidelines employed in Japan, which assign higher importance to disaster prevention function based on field surveys, can be applied effectively for controlling the stand density of P. thunbergii coastal forests in South Korea, to improve their disaster prevention function.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.733-739
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• 2009

This study was carried out to analyze the relationship between major climatic factors (monthly temperature, precipitation) and radial growth of Korean Pine (Pinus koraiensis) in Inje-gun(Mt. Seorak), Sanchung-gun and Namwon-si(Mt. Jiri). Radial growth measurements were crossdated and correlated with climate variables. The climatic factors used were monthly mean temperature and monthly precipitation from August of previous year to September of the current year. In Inje-gun, radial growth was negatively correlated with monthly mean temperature in April, May, June, and August of the current year and was positively correlated with precipitation in August, October of the previous year and in April, August of the current year. Sanchung-gun showed a negative correlation with monthly mean temperature in September of the previous year and August of the current year but positive correlation in January of the current year. In contrast, precipitation in September of the previous year and August of the current year showed a positive influence. The results suggest that high temperature together with low precipitation may thus cause water stress and thereby limit radial growth in this region. In Namwon-si, the climategrowth relationships show that radial growth was negatively correlated with monthly mean temperature in August, October of the previous year and June of the current year. But August of the previous year and May, August of the current year in precipitation was positively correlated with radial growth. In the study areas, precipitation plays an important role for the radial growth of Kroean Pine (Pinus koraiensis). The results suggest that precipitation is important in the radial growth because water deficit in trees would take place in response to high temperature in the study area. Also there was some differences with study areas in the effects of both climatic variables probably as a result of different stand structure and geographical conditions and micro-climate.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.87-90
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• 2013

The average annual and winter ambient air temperatures in Korea have risen by $0.7^{\circ}C$ and $1.4^{\circ}C$, respectively, during the last 30 years. Due to climate change, the occurrence of abnormal weather conditions has become more frequent, causing damage to vegetable crops grown in Korea. Hot pepper, chinese cabbage and radish, the three most popular vegetables in Korea, are produced more in the field than in the greenhouse. It has been a trend that the time for field transplanting of seedlings is getting earlier and earlier as the spring temperatures keep rising. Seedlings transplanted too early in the spring take a longer time to resume the normal growth, because they are exposed to suboptimal temperature conditions. This experiment was carried out to figure out the change of cellular tissue of chinese cabbage under the condition of low temperature to provide the information regarding the coming climatic change, on the performance of 'Chunkwang' chinese cabbage during the spring growing season. In our study, plant height, number of leaf, chlorophyll and leaf area was lower at the open field cultivation than heating house treatment after transplanting 50 days. Especially in fresh weight, compared with heating treatment, open field and not heated treatment were notably low with the 1/3 level. Of damage symptoms due to low temperature cabbage leaves about 10 sheets when $-3.0^{\circ}C$ conditions in chinese cabbage was a little bit of water soaking symptoms on the leaves. $-7.4^{\circ}C$ under increasingly severe water soaking symptoms of leaf turns yellow was dry. Microscopy results showed symptoms of $-3.0^{\circ}C$ when the mesophyll cell of palisade tissue and spongy tissue collapse, $-7.4^{\circ}C$ palisade tissue and spongy tissue was completely collapsed. The result of this study suggests that the growers should be cautioned not to transplant their chinese cabbage seedlings too early into the field, and should be re-transplanting or transplanting other plants if chinese cabbage are exposed to suboptimal temperature conditions ($-3.0^{\circ}C$ or $-7.4^{\circ}C$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.241-250
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• 1982

The structure of gonads, gametogenesis and reproductive cycle of the cockle, Fulvia mutice, were studied mainly by histological observation. The materials were monthly sampled in the southern area of Yeosu from October 1980 to September 1981. F. mutica was monoecious. The gonads were situated between the liver tissues and the outer fibronuscular layers compacted by the connective tissue fibers and muscle fibers beneath the outermost layer of simple cuboidal epithelium. The gonad was composed of a number of the ovarian sacs and the testicular tubules which form the tubular structure. Testicular tubules in the mature stage sometimes contained 'testis-ova' The undifferentiated mesenchymal tissues and the eosinophilic cells were abundantly distributed on the germinal epithelium in the early development stage. With the further development of the ovary and testis, these tissues and cells gradually disapprared. The undifferentiated mesenchymal tissues and the eosinophilic cells are related to the growing of the oocytes and spermatocytes . Early multiplicating oogonium was about $10{\mu}m$ in diameter. As the oocytes grow to $27-34\times50-58{\mu}m$ by increasing cytoplasm, the oocytes connected to the basement membrane by their egg-stalks. The ripe eggs were about $60{\mu}m$ in diameter and they were surrounded by gelatinous membrane. Most male germ cells in mature stage were transformed into the spermatozoa and they formed the sperm bundles. After spawning, undischarged ripe eggs and spermatozoa remained in the ovarian sac and the testicular tubule respectively for some time, then they finally degenerated. Especially the early spent ovarian sacs in May did not contract significantly and then they took part in the secondary maturation within two or three months during the summer season. The monthly changes of the fatness well agreed with the reproductive cycle. The reproductive cycle of F. mutica could be classified into six successive stages : multiplicative, growing, mature, spent, degenerative and recovery stage. It seems that the spawning season is closely rotated to the water temperature, and the spawning occurs from May to October at about $20^{\circ}C$ in water temperature. The peak spawning seasons appeared twice a year between June and July and in September. Acknowledgement The authors wish to express their gratitude to Dr. Kim, In Bae, Dr. Chun, Seh Kyu and Dr. Yoo, Sung Kyoo of National Fisheries University of Busan and Mr. Min, Byoung Seo of National fisheries Research and Development Agency for their critical reading of the manu script.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6852-6859
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• 2015

The purpose of this study was to determine the growth characteristics and distribution pattern of a brackish water clam Corbicula japonica in Seomjin River. Field samples were taken from 14 stations with salinity gradients during spring. Salinity at the bottom layer ranged from 1.0 psu to 32.9 psu, with low salinities in the upper area of the river. In particular, salinity at St.11 was decreased drastically to be ca. 15.0 psu, indicating an intermediate salinity zone. The distribution pattern of C. japonica was related to the salinity gradient, with the highest densities of $2,102ind.m^{-2}$ at Station 13, followed by $1,507ind.m^{-2}$ at Station 11. Here, we focused on the growth characteristics of collected C. japonica collected at two stations with different salinity values. The relationship between shell length and total weight was highly correlated ($R^2=0.91$, P<0.001) at Station 13 compared to that at Station 11 ($R^2=0.72$, P<0.001). On the other hands, the degree of correlation between shell length and shell height (SH) or shell width (SW) at Station 11 (SH: $R^2=0.91$, P<0.001; SW: $R^2=0.69$, P<0.001) was higher than that at Station 13 (SH: $R^2=0.64$, P<0.001; SW: $R^2=0.48$, P<0.001). In addition, fatness index of C. japonica at Station 13 was significantly (P < 0.001) higher than that at St. 11 (t-test value=-22.8, p<0.001). This implies that C. japonica at Station 13 might have enhanced their somatic growth, whereas C. japonica at Station 11 might have this kind of defense mechanism their internal organization against the salinity stress. Ecologically, this kind of defense mechanism of C. japonica against salinity flucuation may play an important role in their survival strategy.

• The Korean Journal of Malacology
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• v.19 no.2
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• pp.161-169
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• 2003

Seawater and sediment quality analysed was calculated to examinate the present environmental characteristics and pollution load was also calculated to evaluate the effect of farming area on the coastal environment. The measurements for seawater quality demonstrate the coastal environment has relatively eutrophicated with significantly decreased DO (0.2-8.5 mg/l) and elevated COD (9.6-31.2 mg/l) in summer. It was also evident that the water quality in Jindong Bay has been influenced by residues tide from Masan Bay with high metal concentration in August of 2002. Annual total pollution load (land and farm-driven) was estimated at 37,316 ton (SS) /yr: 9,809 ton/yr (26.3%) of land-driven load, 23,576 ton/yr (63.2%) of coastal sedimentation and 3,932 ton/yr (10.5%) of feces of cultural organisms. When all ark shell seedling farms are permitted species conversion to ascidian farm, the pollution load would increase by 196%, which may be another source for accelerating the eutrophication of the environment in Jindong Bay.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.4
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• pp.404-411
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• 2007

Adsorption performance of odorous compounds such as geosmin and 2-MIB on granular activated carbon were evaluated in this study. The coal-based activated carbon was found more effective than other carbons in adsorption of geosmin and 2-MIB. The wood-based virgin activated carbon was less effective than coconut- and coal-based carbon in adsorption nevertheless having larger pore volume and specific surface area than others carbons. The maximum adsorption capacity(X/M) of coal-based activated carbon for geosmin and 2-MIB was $1.2\sim1.9$ and $2.1\sim2.6$ times larger than coconut- and wood-based virgin activated carbon, respectively. Carbon usage rate (CUR) of coal-, coconut- and wood-based virgin activated carbons for geosmin and 2-MIB were 1.72 and 1.44 g/day, 1.72 and 2.05 g/day and 2.12 and 1.90 g/day, respectively. In the evaluation of adsorption isotherm of geosmin and 2-MIB for coal-, coconut- and wood-based virgin activated carbons, k value of 2-MIB was lower than geosmin, It menas 2-MIB is more difficult to remove by activated carbon adsorption than geosmin. The relationship of max. adsorption versus total pore volume of coconut- and wood-based virgin and used activated carbon for geosmin and 2-MIB were $y=264,459\times-79,047(R^2=0.95)$, $y=319,650\times-101,762(R^2=0.93)$.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.569-583
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• 2004

The rock properties of the West pagoda in the Gameunsaji temple site are composed mainly of dark grey porphyritic granodiorite with medium grained equigranular texture and developed with small numerous dioritic xenoliths. These xenoliths occurred with small holes due to different weathering processes. As a weathering results, the rock properties of this pagoda occur wholly softened to physical hardness because of a complex result of petrological, meteorological and biological causes. Southeastern part of the pagoda deteriorated seriously that the surface of rock blocks showed partially exfoliations, fractures, open cavities in course of granular decomposition of minerals, sea water spray and crystallization of salt from the eastern coast. The Joint between blocks has small or large fracture cross each other, contaminated and corrupted for inserting with concrete, cement mortar, rock fragments and iron plates, and partially accelerated coloration and fractures. There are serious contamination materials of algae, fungus, lichen and bryophytes on the margin and the surface on the roof stone of the pagoda, so it'll require conservation treatment biochemically for releasing vegetation inhabiting on the surface and the discontinuous plane of the blocks because of adding the weathering activity of stones and growing weeds naturally by soil processing on the fissure zone. Consisting rock for the conservation and restoration of the pagoda would be careful choice of new rock properties and epoxy to reinforce for the deterioration surfaces. For the attenuation of secondary contamination and surface humidity, the possible conservation treatments are needed.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.455-462
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• 2003

A study was conducted to determine the effects of feeding a diet containing no Ca supplement (limestone) during the late finishing period on growth, marbling and serum 1,25-dihydroxy vitamin $D_3$ level in Korean native cattle. Twenty-four steers (20${\sim}$24 mo of age) were divided into two groups of 12 each: one group assigned to a control diet (concentrates containing 2.5% limestone) and the other to a diet containing no calcium supplement. They were allowed to have free access to diets (concentrates and orchard grass hay) and water during the entire feeding period (223 d). Serum $Ca^{2+}$, Ca and P concentrations were not influenced by diets, but serum 1,25-dihydroxy vitamin $D_3$ concentrations determined 2 or 6 mo after the beginning of feeding the experimental diets were higher (P<0.01) in steers fed the diet without Ca supplement than in those fed the control diet (78.3 vs 51.7 and 80.3 vs 51.1 pg/mL, respectively). Steers fed the diet without Ca supplement tended to have a higher intake of concentrates, but a lower intake of hay, compared to those fed the control diet. Average daily gain was higher (P<0.05) in steers fed the diet without Ca supplement than in those fed the control diet. Feeding the diet without Ca supplement remarkably (P<0.01) increased the marbling score (5.1 vs 2.2) and the muscle (M. longissimus dorsi) fat content (10.2 vs 6.7%) with a concomitant decrease in moisture content (67.6 vs 70.4%), compared to feeding the control diet. Ribeye area was increased (77.2 vs 82.8 $cm^2$) with the diet without Ca supplement, compared to the control diet (P<0.05). Meat color, pH and water-holding capacity in longissimus muscle were not different between the two groups. The Warner-Brazler Shear (WBS) force of the longissimus muscle was slightly (P=0.08) lower in steers fed the diet without Ca supplement than in steers fed the control diet (2.9 vs 3.2 kg/1.27-cm diameter core). Sensory evaluation showed that feeding the diet without Ca supplement slightly (P<0.05) improved tenderness (4.9 vs 4.5) and flavor (4.9 vs 4.6), compared to feeding the control diet, but juiciness was not affected by diets. Results showed that deletion of Ca supplement from finishing diets is beneficial, increasing growth and marbling partly through an increased energy intake and induced 1,25-dihydroxy vitamin $D_3$ synthesis that may increase intracellular $Ca^{2+}$ concentration and in turn fat synthesis.