• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.81-92
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• 2001

According to analyses of high-resolution seismic profiles (air gun, sparker, and SBP) and a deep-drill core(YSDP 105) in the mid-eastern Yellow Sea, stratigraphic and geoacoustic models have been established and seismo-acoustic modeling has been fulfilled using ray tracing of finite element method. Stratigraphic model reflects seismo-, litho-, and chrono-stratigraphic sequences formed under a significant influence of Quaternary glacio-eustatic sea-level fluctuations. Each sequence consists of terrestrial to very-shallow-marine coarse-grained lowstand systems tract and tidal fine-grained transgressive to highstand systems tract. Based on mean grain-size data (121 samples) of the drill core, bulk density and P-wave velocity of depositional units have been inferred and extrapolated down to a depth of the recovery using the Hamilton's regression equations. As goo-acoustic parameters, the 121 pairs of bulk density and P-wave velocity have been averaged on each unit of the stratigraphic model. As a result of computer ray-tracing simulation of the subsurface strata, we have found that there are complex ray paths and many acoustic-shadow zones owing to the presence of irregular layer boundaries and low-velocity layers.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.973-979
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• 2010

The objective of this study was to determine the effect of electrical conductivity (EC) of nutrient solution on the growth, nutrient uptake of potted kalanchoe plants ($Kalanchoe$ $blossfeldiana$ 'New Alter') and the nutrient accumulation at the growing media with growth stage in ebb and flow subirrigation systems. Significant differences in leaf area, plant height, and dry weight of the plants were found among the different ECs of nutrient solution of 0.8, 1.6, 2.4, and $3.2dS{\cdot}m^{-1}$. Particularly the difference in plant growth became significantly greater from 5 weeks after treatment. The overall growth was the highest at EC $1.6dS{\cdot}m^{-1}$. Leaf area, plant height, and dry weight were maintained higher when EC increased to $2.4dS{\cdot}m^{-1}$, but rapidly decreased after EC $3.2dS{\cdot}m^{-1}$. The uptake of NO3-N was the greatest while that of $Mg^{2+}$ was the lowest at EC $1.6dS{\cdot}m^{-1}$, even though small differences were found among macro elements. The EC at the top layer of the growing media was 1 to 3 times higher than that at the bottom layer. Nutrient accumulation was accelerated in both the top and bottom layers with growth stage. At EC $3.2dS{\cdot}m^{-1}$, the growth of the plants was suppressed due to higher nutrient accumulation at the growing media. From the results, the strength and composition of nutrient solution should be determined by considering nutrient accumulation at the growing media in addition to EC of nutrient solution in ebb and flow subirrigation systems.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.351-367
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• 1995

The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (＋3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

• Journal of Animal Science and Technology
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• v.52 no.5
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• pp.389-398
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• 2010

The objective of this study was to investigate the effects of three strains of Bacillus subtilis (B. subtilis) supplemented to diets on egg production, egg quality, egg yolk cholesterol levels, the profile of cecal microflora, and tibia characteristics in laying hens. One hundred sixty 76-week-old Hy-Line Brown layers were randomly divided into 4 groups with 4 replicates per group (10 birds per replicate). Birds in the control group were fed a corn-soybean meal based diet. The remaining three treated groups were fed the control diet containing either 0.05% B. subtilis Ch3 (T1), 0.05% B. subtilis Ch3 + B. subtilis W1 (T2) or 0.05% B. subtilis commercial product (T3) for 6 weeks, respectively. There were no differences in feed intake, egg weight, egg production and egg mass among the groups. The dietary supplementation of B. subtilis improved eggshell strength and Haugh units compared to those of control (P<0.05). The activities of GOT and GPT in serum were not also affected by the dietary treatments. The population of total microbes and lactic acid bacteria in cecum were significantly increased by the dietary B. subtilis (P<0.05), but not the coliforms. The cholesterol concentration in egg yolk and serum in the treated groups were significantly decreased compared to those of control (P<0.05). Also, The levels of phospholipids in serum were significantly decreased compared to those of control (P<0.05). The supplementation of three strains of B. subtilis to diets significantly increased the contents of tibia ash compared to that of control (P<0.05). Thus, this study showed significant improvements in egg quality, such as eggshell strength and Haugh unit, by dietary B. subtilis strains. The B. subtilis strains added to the diets modulated the profiles of cecal microflora, reflecting beneficial effects in laying hens.

• Korean Journal of Poultry Science
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• v.34 no.1
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• pp.37-42
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• 2007

This study was conducted to investigate the effects of graded levels of a herbal recipe(Herb Mix $Gold^{(R)}$, Herb BIO Co.) supplemented to a commercial layer diet. The Herb Mix $Gold^{(R)}$ is an improved recipe of Herb $Mix^{(R)}$, fortified with Angelica gigas, Discorea japonica and Ligusticum jeholense. A total of 720 layers (Hy-Line Brown) of 45 wks old were assigned to one of six treatments; control, 0.2% Herb $Mix^{(R)}$, 0.1%, 0.2%, and 0.3% Herb Mix $Gold^{(R)}$, and 6 ppm Avilamycin. Each treatment had 6 replicates of 20 birds each housed in 2 birds cages. Birds were fed diets and water ad libitum for 5 weeks. Hen-day egg production was significantly (P<0.05) different among treatments. Herb Mix $Gold^{(R)}$ 0.2% treatment showed the highest egg production followed by Herb Mix $Gold^{(R)}$ 0.3%, Herb $Mix^{(R)}$ 0.2%, Herb Mix $Gold^{(R)}$ 0.1%, Avilamycin 6 ppm and the control. Hen-housed egg production, egg weight, soft and broken egg ration, feed intake, feed conversion ratio, shell strength, shell thickness, shell color index, Haugh unit and yolk color index were not significantly different among treatments. Nor was cfu of Cl. perfringens and E. coli and Lactobacilli in the small intestinal content significantly different among treatments. The number of white and red blood cells, hemoglobin, heterophil, lymphocyte, thus heterophil to lymphocyte ratio were not significantly modified. It was concluded that Herb Mix $Gold^{(R)}$ at the level of 0.2% in the layer diet improves laying performance.

• Korean Journal of Ecology and Environment
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• v.33 no.2 s.90
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• pp.128-135
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• 2000

The authors surveyed the seasonal variations of environmental factors, the distributions of heterotrophic bacteria and Anabaena cylindrica growth-inhibiting bacteria at each water layer in Daechung Reservoir to verify the role of bacteria during the extinction of bloom. Average water depth at site 1, 2, and 3 were 25.5 m, 15.0 m and 12.3 m, respectively. Water temperature showed a typical pattern seasonally. The variation of DO was relatively inverse proportional to that of water temperature, although it was irregular during summer time. DO decreased gradually to early May, fluctuated sharply after then, and followed by gradual increasement after middle of September. This variation pattern was notable at surface layer. There was remarkable difference in DO concentraion between surface layer and the other water layers during the period in which DO irregulary varied. The variation range of chlorophyll-a concentraion at surface layer in summer time was broad, and it was relatively high when DO was high. The population size of heterotrophic bacteria was high from Spring to Autumn, an declined after September when the water temperature droped rapidly. Especially this variation pattern was prominent at the surface layer. Bacteria that inhibit the growth of A. cylindrica was almost not detected by June, and its distribution increased in July. Afterward, it showed different variation pattern between each site. The distribution of A. cylindrica growth-inhibiting bacteria was higher at the middle and bottom layer than the surface layer in July and October, when it was larger at all sites for the study period. This result suggests that the antagonistic bacteria exhibit higher activity when host activity drops. These results also suggest that natural water bacteria control the distirbution of cyanobacteria, especially its activity as controller is remarkable when cyanobacterial growth declines.

• Korean Journal of Food Science and Technology
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• v.13 no.3
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• pp.171-175
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• 1981

Hand deboned and mechanically deboned chicken meat were produced from domestic broilers and spent layers. Meat yield, chemical composition, functional characteristics, storage stability and microbiogical properties were investigated. The results obtained were as follows: 1. 35% of carcass freight was recovered primarily as hand deboned chicken meat (HDM) and 45% secondarily as mechanically deboned chicken meat(MDM), total meat yield reaching 80% of carcass weight. 2. Moisture, protein, fat. ash and calcium content of MDM were 65, 12, 20, 1.7 and $0.2{\sim}0.4%$, respectively MDM was higher than HDM in fat, ash and calcium, but significantly lower in moisture and protein Total pigment content of MDM was 2.5 times higher than that of HDM, such high content being attributed to the increased inclusion of hemoglobin during the mechanical masceration of carcass in the deboning process. 3. The emulsifying capacity (ES) of MDM per g meat was only 70% that of HDM, but when ES was expressed on unit g of protein basis MDM showed even higher ES than HDM primarily due to the higher proportion of salt soluble protein fraction of MDM. 4. Since the TBA value of MDM increased rapidly after 4 weeks of frozen storage at $-20^{\circ}C$, the maximum possible storage period of MDM is estimated to be about 4 weeks. 5. Total microbial counts of MDM was approximately $1.8{\times}10\;cells/g$ showing no great difference from HDM or red meat.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.1
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• pp.60-67
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• 2010

Although several studies have reported that Cr, Cu and As can leach from CCA-treated woods, few studies have been conducted on this topic in Korea. Therefore, this study was conducted to monitor Cr, Cu and As leaching from CCA-treated wood products and to develop a rapid identification method for CCA-treated wood products by using indicators such as PAN stain. Soil samples were collected at depths of 0-70 cm and wood samples were collected by thickness of wood layer. The soil and wood samples were then digested and analyzed for Cr, Cu and As concentrations using an atomic absorption spectrometer. The As and Cu concentrations decreased sharply with depth from 34.38 and 33.65 mg $kg^{-1}$ at 0-1 cm to 1.72 and 7.84 mg $kg^{-1}$ at 70 cm, respectively. In general, As was more mobile than Cr and Cu in the soil. For wood samples, the Cr, Cu and As concentrations were higher in the outer layer (0-0.5cm) than the inner layers (0.6-4.5cm). Evaluation of rapid identification methods revealed that 100% acetone with 0.1% PAN indicator was the best combination for detection of CCA-treated wood in the field.

• Journal of Wetlands Research
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• v.1 no.1
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• pp.29-44
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• 1999

Vegetation structure and distribution of the vascular hydrophytes and hygrophytes, and the growth pattern, standing crop and amounts of nutrient uptake by Salix species were investigated in the upper stream wetlands of the Namgang-Dam, Chinju-city, Gyeongsangnam-do, Korea from April to November in 1997. The flora was composed of 43 hydrophytes and 241 hygrophytes, or total 284 vascular plants. The life forms of the hydrophytes were classified as 27 kinds of emergent plants, 4 floating-leaved plants, 3 free-floating plants, and 9 submersed plants. In the herb layer, the dominant species was Persicaria hyciropiper, and the ranges of the species diversity indices (H'), equitabilities, (J') and community similarity indices (CCs) were 1.59~1.89, 0.87~0.96, and 0.35~0.83, respectively. In the shrub and subtree layers, 17 kinds of Salix species were supposed to the pioneer plants at the early stage of the succession. The number of branches per main stem of Salix species was 5.0. The DBH class-frequency histograms of Salix species were the reverse J type, and the natural regeneration of the Salix community was expected. Basal area of Salix species per square meter was $24.87cm^2$. Volume of Salix species per square meter was $12,008cm^3$ and total phytomass of the Salix species was estimated as 12,894 ton. Biomass distribution of Salix species in the stem, the branch and twig, and the leaf was 64.1%, 28.1%, and 7.8%, respectively. The amounts of nitrogen and phosphorus absorbed by Salix species were 68,022 and 19,823 kg. It was recommended that application and conservation of the wetland and other counterplans are indispensable to reduce the adverse effects of water pollution and to preserve the wetland ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.45-55
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• 1998

Phytoplankton community and primary productivity have been investigated in a fall season in the southern coastal waters of the last Sea, Korea. A strong thermocline formed at the 20\~60\;m$ layer and a cold water mass also existed in the bottom around Yong-il Bay. The offshore of the surveyed area was likely to be influenced by relatively warmer water, whereas the inshore represented Higher primary productivity with lower water temperature and lower salinity. A total of 133 species of phytoplankton occurred, representing 107 spp. of diatom, 23 spp. of dinoflagellate 3 spp. of silicoflagellate. Skeletonema costatum and Asterionellepsis glacialis were most predominant with more than $30\%$ dominance ratio, while Leptocylindrus danicus was also dominant at all transect lines. Standing crops of phytoplankton ranged from $2.7{\times}10^3\;to\;141.6{\times}10^3\;cell^{\ell-1}$. Chlorophyll a concentration varied with stations and layers, but the $30\~50$ m layer showed maximun with about $1.18{\mu}g{\ell}^{-1}$ rather than at the surface layer. It is believed that the maximun in standing crops and chlorophyll of phytoplankton formed at the $20\~50$ m layer above the thermocline during the survey. Phytoplankton primary productivity ranged from 0.32 to 3.04 mgC $m^{-3}\;hr^{-1}$, showing higher at the inshore than at the offshore. The range of integrated primary productivity was $263.3\~1085.5 mgC\;m^{-2}\;day^{-1}$ for the euphotic layer. Photosysthesis rates varied with the range from 0.76 to 8.04 mgC mgChl $\alpha^{-1}\;hr^{-1}$. Phytoplankton photosynthesis at the inshore was saturated at lower irradiance ($15\~35\%$ of surface) and showed higher efficiency, Thus, it revealed that the phytoplankton community probably adapted to the middle of euphotic layer because the depth of mixing layer became thinner due to the formation of thermocline.