• 한국해양학회지
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• v.24 no.4
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• pp.165-171
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• 1989

To examine the sample variability of zooplankton, samples were collected at two stations in the nearshore off Anhung (Chungnam, Korea), using a NORPAC net (76 Cm diameter, 0.333 mm mesh size) for two days, April 5 and 6, 1989. The net was towed vertically to eliminate the source of variation due to vertical migration. During the period of 6 hours, triplicate sampling was done every one or two hour at each station. Species composition and abundances at two stations were not so different, but the abundances at each station varied greatly with respect to sampling time. Greater abundance at one sampling time ranged 2.3-8.7 times of smaller abundance at another sampling time. At the level of ${\alpha}=0.05$, however, mean abundances of different sampling time did not differ significantly from each other due to the large variance. It was believed that the large variance was caused by the time dependent effect of patchiness of which parameters were varied with time because of sea water movement. From the variation within the triplicate samples, it was considered that the abundance data obtained from single tow were not significantly different from the data in the range of 50-200% of those from single tow. From these results, the necessity for the replicate and time dependent sampling was indicated. In the nearshore like the sampling site of this study, it seemed to be better to reduce the number of stations for the replicate and time dependent sampling though the proper sampling scheme was to be decided based on the goal of the study.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.124-133
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• 2009

Effects of substrates on the relative immigration activities (RIAs) of epilithic diatoms were examined in Sum River, a tributary of South Han River, Korea. Two hundreds of tile substrates coated with 5% agar were deposited at seven study stations (30 tiles per site) for one month from March 7 to April 7, 2008. Water sampling, physico-chemical factor measurement, and diatom analysis were performed in the field and laboratory. Over the study, major epilithic diatom species were Nitzschia amphibia, Navicula subminuscula, Cymbella minuta in both the natural and artificial substrates. Two dominant species, Nitzschia amphibia and Cymbella minuta often found at seven stations. Among all observed taxa, Nav. subminuscula and Caloneis silicula showed the highest RIA, with the value over 15 throughout the study. Regarding the algal morphology, the biraphe type species showed higher RIA than any other morph, while they comprised over 55% of total biomass, indicating a density effect. Additionally, a significant relationship between RIA and 20-day deposited substrate (p<0.05) showed in two diatom species, Nitzschia fonticola, Gomphonema quadripunctatum, which showed relatively high RIAs. These results indicate that the relative immigration activities of epilithic diatom species can be influenced by algal density in the water and substrate, nutrients, and deposited time at least 20 days.

• Journal of Life Science
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• v.12 no.1
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• pp.113-119
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• 2002

The cloning and expression of Phosphotyrosine Protein Phosphatase into E. coli provides important tools of understanding of its functions and signal transduction mechanisms. The abundant soluble protein of the Phosphotyrosine Protein Phosphatase A (PtpA) and the active site mutant PtpA(C9S) were produced using the expression vector pET26 in E. coli and pIJ6021 with the thiostrepton in S. lividans. The enzyme activity of both proteins extracted by Ni-NTA column had same results from the expression vector pET26 and pIJ6021. The enzyme activity of phosphatase was found in the protein of PtpA, but not in that of C9S. The western blot detected by penta His-tag antibody resulted in the inducer, thiostrepton was not a good trigger to induce a large amount of PtpA protein. The overexpression of both proteins had no significantly different effect on the A factor cascade related to the secondary metabolite and mycelium formation between PtpA and C9S. However, overproduction of PtpA protein using pIJ6021 in S. lividans brought about a dramatic decrease in the amount of phosphotyrosine proteins (p200, p90, and p65), but no significantly phenotypic variation in S. lividans. This indicates that PtpA has an important proteome role in signal transduction mechanism of producing massive amount of phosphotyrosine protein in Streptomyces sp.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.3
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• pp.169-175
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• 1985

This experiment was carried out during 1983-1984 to determine an effective method for the introduction of pasture species on nonarable hill country without cultivation. In this experiment, 1.8 and 2.8kg a.i. $ha^{-1}$ rates of glyphosate and a 0.7kg a.i.$ha^{-1}$ rate of paraquat were applied, and also 30, 45 and 60 days intervals between spraying and sowing were used. Establishment of orchardgrass (Dactylis glomerata) was not affected by the application of herbicides, but that of ladino clover (Trifolium repens) was significantly affected by glyphosate and paraquat. It was found that glyphosate and paraquat have no apparent soil residual activity or pre-emergence effect when sprayed 30 to 60 days before sowing. Dry matter yield of pasture species on the herbicide treatments was significantly higher than that on the unsprayed treatments. The highest yield was obtained from the 1.8kg a.i.$ha^{-1}$ rate of glyphosate 45 days before sowing. Botanical analysis at the final cut showed that the shrubs and native grass of original site were reduced to 5% by glyphosate application, but those on the unsprayed control were still 51%. Crude protein content and in vitro dry matter digestibility of herbage on the herbicide treatments were higher than those on the unsprayed treatments. Results indicated that glyphosate was more effective to control resident shrubs and grass than paraquat, and good establishment and higher yield of surface-sown pasture species can be obtained by spraying 1.8 to 2.8kg a.i.$ha^{-1}$ of glyphosate, 30 to 45 days before sowing.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.9-18
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• 2007

The purposes of this study were to examine the variability of adhesive thickness on the different site of the cavity wall when used total-etch system without filler and simplified self-etch system with filler and to evaluate the relationship between variable adhesive thickness and microtensile bond strength to the cavity wall. A class I cavity in six human molars was prepared to expose all dentinal walls. Three teeth were bonded with a filled adhesive, $Clearfil^{TM}$ SE bond ana the other three teeth were bonded with unfilled adhesives, $Scotchbond^{TM}$ Multi Purpose. Morphology and thickness of adhesive layer were examined using fluorescence microscope. Bonding agent thickness was measured at three points along the axial cavity wall edge of cavity margin (rim). halfway down each cavity wall (h1f), internal angle of the cavity (ang). After reproducing the adhesive thickness at rim, h1f and ang, micro-tensile bond strength were evaluated. For both bonding agents, adhesive thickness of ang was significantly thicker than that of rim and h1f (P <0.05). As reproduced the adhesive thickness, microtensile bond strength was increased as adhesive thickness was increased in two bonding agents. Adhesive thickness of internal angle of the cavity was significantly thicker than that of the cavity margin and the halfway cavity wall for both bonding agents. Microtensile bond strength of the thick adhesive layer at the internal angle of the cavity was higher than that of the thin adhesive layer at 1,he cavity margin and the halfway cavity in the two bonding systems.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.1-9
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• 2008

In seismic response analysis of building structures, the input ground accelerations have considerable effect on the nonlinear response characteristics of structures. The characteristics of soil and the locality of the site where those ground motions were recorded affect on the contents of earthquake waves. Therefore, it is difficult to select appropriate input ground motions for seismic response analysis. This study describes a generation of artificial earthquake wave compatible with seismic design spectrum, and also evaluates the seismic response values of multistory reinforced concrete structures by the simulated earthquake motions. The artificial earthquake wave are generated according to the previously recorded earthquake waves in past major earthquake events. The artificial wave have identical phase angles to the recorded earthquake wave, and their overall response spectra are compatible with seismic design spectrum with 5% critical viscous damping. The input ground motions applied to this study have identical elastic acceleration response spectra, but have different phase angles. The purpose of this study is to investigate their validity as input ground motion for nonlinear seismic response analysis. As expected, the response quantifies by simulated earthquake waves present better stable than those by real recording of ground motion. It was concluded that the artificial earthquake waves generated in this paper are applicable as input ground motions for a seismic response analysis of building structures. It was also found that strength of input ground motions for seismic analysis are suitable to be normalize as elastic acceleration spectra.

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.27-36
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• 2016

Low Impact Development (LID) techniques are eco-friendly storm water management process for water circulation restoration and non-point pollutant reduction. In this study, four LID techniques (Small constructed wetland, Infiltration trench box, Infiltration trench, Vegetated swale) were selected and installed as a real size at the real site. All facilities were evaluated as monitoring under the real environmental climate situation and an artificial rain with exceeding design rainfall. In various rainfall, runoff reduction efficiency and non-point pollutant removal efficiency are increased to the bigger Surface Area of LID (SA)/Catchment Area (CA) ratio and the bigger Storage Volume of LID (SV)/Catchment Area (CA) ratio. Runoff did not occur at all rainfall event (max. 17.2 mm) in infiltration trench and vegetated swale. But Small constructed wetland was more efficient at less than 10 mm, a efficiency of infiltration trench box was similar at different rainfall. Although different conditions (such as structural material of LID, rainfall flow rate, antecedent dry periods), LID techniques are good effects not only water circulation improvement but also water quality improvement.

• FLOWER RESEARCH JOURNAL
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• v.19 no.3
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• pp.144-150
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• 2011

This study was carried out to develop the soil amendment practice by phosphate solubilizing bacteria application in greenhouse chrysanthemum cultivation area with high salt accumulation. The experimental site (ShinWoo Flower, GwangJu) has been cultivated chrysanthemum for 15 years and showed significant salt accumulation. The phosphate solubilizing bacteria, Pseudomonas putida (KSJ11), Acinetobacter calcoaceticus (KSJ3) and Acinetobacter calcoaceticus (WP20) formulated on vermiculite for easy use, were applicated. Each 250L of phosphate solubilizing bacteria was applied for $82m^2$ before planting. Acinetobacter calcoaceticus (KSJ3; WP20) increased the amount of soluble phosphorus in an effective level. Particularly, Acinetobacter calcoaceticus (WP20) increased not only the level of soluble phosphorus but also potassium, calcium and magnesium resulting in the increase of EC in the soil. The level of nematode was also decreased with the non-treated increased. As a result, we suggest that selected phosphate solubilizing bacteria (WP20) could be a useful practice for soil amendment in chrysanthemum plantation soil and provided an opportunity to reduce the use of the fertilizer during the cultivation period.

• Journal of agriculture & life science
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• v.45 no.5
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• pp.97-103
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• 2011

The purpose of this study was to analyze the pollutant reduction effect for non-irrigated crop land by nonpoint source pollution control. For a field scale monitoring, 6 plots (5m width and 22m length) and 3 sediment traps were installed. At the outlet of each plot, the stage gauges were installed for runoff monitoring. For a rainfall monitoring, tipping bucket rain gage was installed within the experiment site. Through the artificial irrigation, runoff from the plots were monitored. The SS, TOC, T-N, T-P, COD, NTU of sampled water were analyzed by standard methods. The SS, TOC, T-N, T-P, COD, NTU concentration of initial runoff were 15.00, 1.54, 5.27, 0.07, 4.72, 0.45mg/L, respectively. Four hours later than the initial runoff, the concentration was changed to 1.00, 0.94, 4.06, 0.01, 0.60, 0.33 mg/L, respectively. As a result of artificial irrigation, three out of four sediment traps were filled with runoff water from the experimental plots. One sediment trap was not filled with runoff water because the artificial irrigation was not supplied for two experimental plots. The stage of sediment traps were gradually lowered. However, the water quality didn't showed a decrease trend as the stage went down because the suspended solid was not equally collected during the water sampling.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.367-371
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• 2019

In this study, we proposed the sacrificial anode cathodic protection method as a countermeasure to reduce the corrosion of railway rails under oceanic climatic conditions and proved the anticorrosive effect experimentally. In addition, the proposed sacrificial anode cathodic protection method were tested on site to examine long-term rail corrosion monitoring and field applicability for more than 26 months and to prove the effectiveness of rail corrosion. As a result of monitoring the corrosion state using the cellophane tape method, the appearance of the applied sections with sacrificial anode cathodic protection method was good at the present time about 26 months after the field test laying, and no abnormalities and other abnormalities of the rail welded section and the rail web were found. Hence, in places where no sacrificial anodes were installed, rust progressed rapidly. In addition, the proper spacing of sacrificial anodes was found to form the most stable corrosion coating at 1.0 ~ 1.5m. After about 26 months of monitoring, the installation of sacrificial anodes could help stabilize the overall rail corrosion level, even if the spacing was somewhat wider.