• Journal of Food Hygiene and Safety
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• v.15 no.2
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• pp.137-143
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• 2000

The present study was performed to investigate the bioconcentration of phosphamidon and profenofos. The BCFs(bioconcentration factors), depuration rate constants and LC$_{50}$ for two pesticides in zebrafish(Brachydanio rerio) were measured by the flow-through system(OECD guideline 305). The results obtained are summarized as follows: The 24-hrs LC$_{50}$, 48-hrs LC$_{50}$, 72-hrs LC.n and 96-hrs LC$_{50}$ were more than 100 mg/l for phosphamidon. The concentration of phosphamidon in zebrafish reached an equilibrium in 12 hrs at low and high concentrations(0.2 mg/l and 1 mg/1). The average BCF values of phosphamidon were less than 1 at low(0.96, n=7) and high concentrations (0.89, n=7) after 12~168 hrs. Depuration rate constants of phosphamidon were 0.18 hr-1 and 0.21 hr-1, half-life of phosphamidon were 3.85 and 3.30 at low and high concentrations(0.2 mg/l and 1 mg/l), respectively, The concentrations of phosphamidon in zebrafish at low and high concentrations were rapidly decreased after 8(0.04 $\mu\textrm{g}$/g) and 12 hrs(0.07 $\mu\textrm{g}$/g). The 24-hrs LC$_{50}$, 48-hrs LC$_{50}$, 72-hrs LC$_{50}$ and 96-hrs LC$_{50}$ were 2.9, 2.6, 2.2 and 2.0 mg/1 for profenofos. The concentration of profenofos in zebrafish reached an equilibrium in 12 hrs at five-hundredth and one-hundredth concentration of 96-hrs LC$_{50}$(0.004 mgA and 0.02 mg/1). The average BCF values of profenofos were 141.9(n=7) and 111.3(n=7) at five-hundredth and one-hundredth concentration of 96-hrs LC$_{50}$(0.004 mg/l and 0.02 mg/1) after 12~168 hrs. Depuration rate constants of profenofos were 0.09 hr$^{-1}$ and 0.10 hr$^{-1}$, half-life of profenofos were 7.70 and 6.93 at five-hundredth and one-hundredth concentration of 96-hrs LC50(0.004 mg/l and 0.02 mg/1), respectively. The concentrations of profenofos in zebrafish at five-hundredth and one-hundredth concentration of 96-hrs LC$_{50}$ decreased agter 8(0.18 $\mu\textrm{g}$/g) and 12 hrs (0.19 $\mu\textrm{g}$/g). The LC$_{50}$ value in zebrafish showed that acute toxicity of profenofos was higher than that of phosphamidon. The BCF values of profenofos were 100 times higher than those of phosphamidon, and depuration rate of phosphamidon was two times faster than that of profenofos.

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.2
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• pp.95-106
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• 2010

The performance of Community Land Model version 3.5 - Dynamic Global Vegetation Model (CLM-DGVM) was evaluated through a comparison with the observation over temperate deciduous forest in Gwangneung, Korea. Influence of plant phenology, composition of plant functional type, and climate variability on carbon exchanges was also examined through sensitivity test. To get equilibrium carbon storage, the model was run for 400 years driven by the observed atmospheric data at the deciduous forest of the year 2006. We run the model for 2006 with the equilibrium carbon storage at Gwangneung forest and compared the model output with the observation. A comparison of leaf area index (LAI) between the model and observation indicated that the simulated phenology poorly represented the timing of budburst, leaf-fall, and evolution of LAI. Senescence of the phenology was delayed about four weeks and the simulated maximum LAI (of 5.8 $m^2$ $m^{-2}$) was greater than the observed value (of 4.5 $m^2$ $m^{-2}$). The overestimated LAI contributed to overestimation of both gross primary productivity (GPP) and ecosystem respiration $(R_e)$ through increased photosynthesis and foliar autotropic respiration $(R_a)$, respectively. Despite the discrepancy between the simulated and observed LAI, the simulated tree carbon storage amounts were comparable with the reported values at the site. Change in plant phenology from the simulated to the observed reduced more than six weeks of the plant growth period, resulting in the decreased amount of GPP and $R_e$. These values, however, were still higher (~10% of GPP and 40% of $R_e$) than the observed values. The effect of change in plant functional type composition (from dominant temperate deciduous forest to the coexistence of temperate deciduous and needle leaf forests) on the estimated amount of GPP and $R_e$ was marginal. The influence of climate variability on carbon storage amounts was not significant. The simulated inter-annual variation of GPP and $R_e$ from 1994 to 2003 depended on annual mean air temperature and total radiation but not on precipitation. Other deficiencies of CLM3.5-DGVM have been discussed.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.75-84
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• 2005

The aim of this study is to evaluate the leaching characteristics of lead, copper, cadmium, and mercury from steel making slag by seawater. To demonstrate the leaching characteristics of heavy metals from steel making slag by seawater, it was carried to various leaching tests such as regular leaching tests, liquid/sold(LS) leaching test and pH static test. From the leachability of $Pb^{+2},\;Cu^{+2},\;and\;Cd^{+2}$ from steel making slag in pH static test, it is distinguished between distilled water and seawater. With distilled water, it is very low between pH 7-8 and pH 11-12. On the other hands, with the seawater, its leaching is higher than that of distilled water. In particular, concentration of $Hg^{+2}$ leached from slag by seawater is lower than that of distilled water. Meanwhile, we found that the heavy metals from steel making slag would be dissolved and precipitated using geochemcial equilibrium program such as visual minteq. Lead and copper leached from steel making slag with seawater were dissolved nearly in the range of pH 11-12, but in the range of pH 7-10 those were precipitated about 90%. And cadmium leached from steel making slag with seawater were dissolved completely. On pH static test with distilled water, lead leached from steel making slag seemed to be similar to pH static test with seawater. However, copper and cadmium leached from steel making slag were dissolved. In general, the species of lead leached from steel making slag were formed mainly of $PbCl^+,\;PbSO_4$, the species of copper were formed mainly of $CuSO_4,\;CuCO_3$, the species of cadmium were formed mainly of $CdCl^+,\;CdSO_4$ due to being sorbed with the anions($Cl^-,\;CO_3^{-2},\;SO_4^{-2}$) of the seawater. Both pH static test with seawater and distilled water, it is not in the case of the mercury. Most of mercury leached from steel making slag was precipitated(SI=0). Because the decreasing of $Hg^{+2}$ concentrations depends ferociously on the variation of chloride($Cl^-$) existed in the seawater. $Hg^{+2}$ leached from steel making slag could be sorbed strongly with chloride($Cl^-$) compared of carbonate($CO_3^{-2}$) and sulfate($SO_4^{-2}$) in the seawater. On the basis of that result, we found that the species of mercury was formed of calomel($Hg_2Cl_2$) as one of finite solid. Due to forming a calomel($Hg_2Cl_2$) in the seawater, the stability of mercury species by steel making slag should be higher than those of lead, copper, and cadmium species. Regarding the results stated above, we postulated that the steel making slag could be recycled to sea aggregates due to being distinguishing leachability of heavy metals($Pb^{+2},\;Cu^{+2},\;Cd^{+2},\;and\;Hg^{+2}$) between leaching tests by distilled water and seawater.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.59-71
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• 2015

Purpose : This study examines the effect of vibration exercise grafting PNF patterns for 6 weeks on upper body stability and equilibrium for seniors having fifteen or over of MMSE-K. Method : A total of 10 senior citizens participated in this study. Each participant performed PNF patterned exercises using vibration sports equipment for 30 minutes, once static a week, for six weeks. We measured trunk stability and balance degree before and after the six-week exercise program. Motor Assessment Scale (MAS) was used to measure trunk stability, while Functional Reach Test (FRT) and Timed Up and Go (TUG) was used to measure balance degree. The collected data was processed using paired t-test to confirm the difference between pre-program conditions and post-program conditions. Results: The results of our study show that post-program trunk stability measurements increased when compared to pre-program data; however, this increase was not statistically significant. pre and post-measurements for satatic balance and dynamic balance were statistically unchanged. Conclusion: Due to limitations in the number of participants, the procedural design of this experiment, and the limited amount of time participants actually controlled, this study failed to produce statistically significant results. However, further study should be conducted using a systematically implemented exercise program to show support for exercising with flexi-bar as an effective program for the elderly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4725-4732
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• 2012

This paper studies MR16 that can strengthen the strength and make up for the weakness of MR16 by replacing halogen light source using multifaceted Reflector(MR16) with LED light source. To achieve this, developed MR16 for LED applying optical system that four aspheric lens is one sheet. Optical system is designed by optics software and lighting performance of the designed data is predicted lighting simulation program. Also, heatsink's heat radiation analysis program to predict the thermal performance. Finally, optical prototype system based on simulation analysis data is manufactured and the results comparing performance of the developed system and the designed data are follows: Radiation angle was around $50^{\circ}{\sim}60^{\circ}$ in results of simulation analysis and the test of the prototype system. Also, temperature measurement result indicates that the thermal equilibrium is realized after one minute and thirty seconds and heat is generated up $60^{\circ}C$ in all of simulation analysis and the test of the prototype system. Finally, simulation analysis result on light disturbance curve of MR16 is similar to that of performance of the prototype system.

• Journal of Soil and Groundwater Environment
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• v.8 no.3
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• pp.37-44
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• 2003

Fuel oxygenates, such as Methyl tertiary Butyl Ether (MTBE) is additive in gasoline used to reduce air pollution. Gasoline components and fuel additives can leak: form underground storage tanks. MTBE is far more water soluble than gasoline hydrocarbons like BTEX then it travels at essentially the same velocity as groundwater. MTBE in drinking water causes taste and odor problems. Therefore, the purpose of the this study is to examine the ability of ground tire to sorb MTBE in water. The study consisted of running both batch and column tests to determine the sorption capacity, the required sorption equilibration time, and the flow through utilization efficiency of ground tire. The batch test result indicated that ground tire can attain equilibrium sorption capacities about 0.5 mg of MTBE. The result of column test indicate that ground tire has on the 36% utilization rate. Finally, it is clear that ground tire represented an attractive and relatively inexpensive sorption medium for a MTBE. Authors thought that to determine the economic costs of ground tire utilization, the cost to sorb a given mass of contaminant by ground tire will have to be compared to currently accepted sorption media. The cost comparison will also have to include regeneration and disposal cost.

• Journal of the Korea Concrete Institute
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• v.13 no.6
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• pp.584-592
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• 2001

The cracks are developed in reinforced concrete(RC) beams at the early stage of service load because of the relatively small tensile strength of concrete. The structural strength and stiffness are decreased by reduction of tensile resistance capacity of concrete due to the developed cracks. Using the fiber reinforced concrete that is increased the flexural strength and tensile strength at tensile part can enhance the strength and stiffness of concrete structures and decrease the tensile flexural cracks and deflections. Therefore, the RC beams used of the fiber reinforced concrete at. tensile part ensure the safety and serviceability of the concrete structures. In this work, analytical model of a dual concrete beams composed of the normal strength concrete at compression part and the high tension strength concrete at tensile part is developed by using the equilibrium conditions of forces and compatibility conditions of strains. Three groups of test beams that are formed of one reinforced concrete beam and two dual concrete beams for each steel reinforcement ratio are tested to examine the flexural behavior of dual concrete beams. The comparative study of total nine test beams is shown that the ultimate load of a dual concrete beams relative to the RC beams is increased in approximately 30%. In addition, the flexural rigidity, as used here, referred to the slope of load-deflection curves is increased and the deflection is decreased.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.11
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• pp.1180-1185
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• 2005

Iron sand, having iron as a major component, was applied in the treatment of synthetic wastewater containing Cu(II) or Pb(II). To investigate the stability of iron sand at acidic condition, dissolution of Fe and Al was studied with variation of solution pH ranging from 2 to 4.5. Iron concentration in the extracted solution was below the emission regulation of wastewater even at a strong acidic condition, pH 2. Although an important concentration of aluminum was extracted at pH 2, the dissolution greatly decreased above pH 3. This stability test suggests that application of iron sand has little problem in the treatment of wastewater above pH 3. Adsorption capacity of Cu(II) and Pb(II) onto iron sand was investigated in a batch and a column test. In case of Cu(II), rapid adsorption was noted, showing 50% removal within 2 hrs, and then reached a near complete equilibrium after 24 hrs. Adsorption was favorable at higher pH in each metal ion and showed a near complete removal above pH 6, indicating a typical cationic-type adsorption. From the adsorption isotherm obtained with variation of the concentration of each metal ion, the maximum adsorption capacity of Cu(II) and Pb(II) was identified as 2,170 mg/kg 및 3,450 mg/kg, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.663-672
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• 2009

In this studies, the adsorption test using Chlorella pyrenoidosa was conducted to examine the effect of Pb adsorption according to various immobilized methods such as Ca-alginate, K-carrageenan, and Polyacrylamide. From the results, the duration to need to reach adsorption equilibrium was delayed according to the immobilization. And, the higher adsorption capacity of immobilized Chlorella pyrenoidosa was represented in the higher concentration of Pb, the smaller amount of immobilizing agent, and the higher pH of solution. The maximum adsorption capacity of Pb was shown in the adsorption test using Chlorella pyrenoidosa immobilized with Ca-alginate even though it was sensitive pH. The adsorption results properly represented with Freundlich isotherm equations. And, pseudo second-order chemisorption kinetic rate equation was applicable to all the biosorption data over the entire time range. The FT-IR analysis showed that the mechanism involved in biosorption of Pb by Chlorella pyrenoidosa was mainly attributed to Pb binding of carbo-acid and amide group. Adsorbed Pb on immobilized Chlorella prenoidosa was easily desorbed in the higher concentration of desorbents(NTA, HCl, EDTA, $H_2SO_4,\;Na_2CO_3$). Among the several desorbents, NTA showed the maximum desoption capacities of Pb from Chlorella pyrenoidosa immobilized with Ca-alginate and K-carrageenan and EDTA was the most effective in Chlorella pyrenoidosa immobilized with polyacrylamide. The desoprtion efficiency in the optimum condition was 90.0, 83.0, and 80.0%, respectively.

• Journal of Korea Technology Innovation Society
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• v.10 no.1
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• pp.47-72
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• 2007

Ideas do not become exhausted, and there are no diminishing returns in the creation of knowledge. Nonetheless, growth ultimately ceases in this simplest model of endogeneous innovation. The reasons are similar to those that are discussed in the context of the neoclassical model of capital accumulation. Even if the resource cost of creating new goods does not rise, the economic return to invention may decline as the number of available products increases. When the rate of return to R&D falls to the level of the discount rate, private agents cease to be willing to defer consumption in order to invest in product development. But, if we treat knowledge capital as a public capital considering of its non-appropriable benefits, economic growth can be sustained in the economy. Romer(1986) has pointed out that growth might be sustainable if the accumulation of knowledge is not subject to long-run diminishing returns. Actually Romer assumed diminishing returns in the production of private knowledge from available resources, but increasing returns in the production of output from labor and total (public and private) knowledge. His condition for the sustainability of long-run growth amounts to an assumption that the diminishing returns in the former activity do not outweigh the increasing returns in the latter. The Johansen(1988) cointegration test method is used for finding long-run equilibrium relationship between R&D input and the product innovation. Test results indicate the existence of cointegrating equation between each pair of regression variables including dependent variable in the knowledge production function. And, the signs of cointegrating vectors are well accord to the prediction of sustainable growth. In the empirical analysis, from all cases of the form for the knowledge production function, we could not reject the null hypothesis that R&D spillover effect is significant($H_{0}:\;{\gamma}=1$). In summary, we showed that considering goodness of fit of regression model, we can see that the empirical evidence is strongly in favor of the character of knowledge as the public knowledge capital. So, we can expect that by product innovation, economic growth can be sustained in the Korean economy.