• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.3
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• pp.221-225
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• 2002

This study was conducted to identify the effects of slow release fertilizer (LCU) on ridge direct seeding on dry paddy of rice as an irrigation water-saying cultural system. During 1999-2000, a series of experiments was carried out at field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Plant height and culm length during the total growth duration were the longest and panicle umber per $m^2$ was the highest in 100% LCU application rate. Leaf area index and top dry weight were the highest in the 100% LCU application rate. They increased as more LCU was applied. Nitrogen uptake was the highest in 100% LCU application, and N use efficiency was the highest in LCU 60% + FP (fertilization at panicle formation stage) 20% application. Milled rice yield was 7% higher in 100% LCU application rate than that of conventional N application. Ripened grain rate and 1,000-grain weight of brown rice did not differ, but panicle number per $m^2$ and grain number per m2 were the highest at 100% LCU application.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.533-542
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• 2015

In order to investigate the effect of internal loading from sediment on algal blooming at Chusori area in Daechung Reservoir, the amount and contamination level of sediment and the release rate of total phosphorus were analyzed. The sedimentary layer was consisted with two layers, and the average depth of upper and lower ones were 0.35 and 1.44 m, respectively. The fraction of inorganic phosphorus in the sediment was higher than that of organic phosphorus, and the fractions of phosphorus which responsible for internal loading were very high as in the range of 72.7 and 80.2% of inorganic phosphorus. The C/N ratio of sediment taken with core sampler indicated the organic compounds are originated from settled algae from water body. The average release rate of total phosphorus from sediment was $6.74({\pm}0.50)mg/m^2/day$. These results indicated that the internal loading from sediment contributes the excessive algal growth at Churosi area, and the countermeasures to improve the quality of sediments are required to manage algal blooming in Daechung Reservoir.

• Korean Journal of Microbiology
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• v.39 no.1
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• pp.8-15
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• 2003

To evaluate the effects of slow release fertilizer and chemical dispersant on oil biodegradation, mesocosm studies were conducted on sand seashore. The rapid removal rates (85%) of aliphatic hydrocarbons and the simultaneous decreases of n-$C_{17}$/pristane (69%) and $n-C_{18}/phytane$ (61%) ratios by the addition of slow-release fertilizer (SRF) within 37 days of experiment indicated that SRF could enhance the oil degrading activity of indigenous microorganisms in sand mesocosm. Although the growth of heterotrophic bacteria and petroleumdegrading bacteria in the mesocosm treated with $Corexit 9527^{R}$ was stimulated, the biological oil removal based on the ratios of $Corexit 9527^{R}$ and $n-C_{18}/phytane$ was inhibited. Removal rates of aliphatic hydrocarbons (56%), and n-$C_{17}$/pristane (27%) and $n-C_{18}/phytane$ (17%) ratios by the addition of chemical dispersant $Corexit 9527^{R}$ were similar or lower than those values of control (50, 60, 46%), respectively. The biodegradation activity, however, when simultaneously treated with SRF and $Corexit 9527^{R}$, was not highly inhibited and even recovered after the elimination of chemical dispersant. From these results it could be concluded that the addition of SRF enhanced the oil removal rate in oligotrophic sand seashore and chemical dispersant possibly inhibit the oil biodegradation. Hence, in order to prevent the unrestrained usage of chemical dispersant in natural environments contaminated with oil, the National Contingency Plan of Oil Spill Response should be carefully revised in consideration of the application for bioremedaition techniques.

• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.407-415
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• 2006

This study carried out submerged area due to Dam construction in the near future. It includes species classification of plant, survey of community structure, examination of pollutant load and assessment of water quality impact. The vascular plants of this area are listed 224 taxa; 64 families, 168 genera, 193 species, 30 varieties and 1 form. This study area is classified into total 21 communities, most community was consist of grass vegetation. Among the communities, Erigeron annuus ($869,286m^2$, 22%) community was dominant and Erigeron annuus-Avena fatua comminity (16%) was subdominant until May, and then Erigeron canadensis community occupied most area to $1,774,985m^2$ (32%) from May to July. For the evaluation of water quality impact due to submerged macrophyte, nutrient release test was conducted both dead body macrophyte and living body macrophyte. The results of release test show that T-N is not released at dead body macrophyte, but it is released at living body macrophyte, especially living body Artemisia priceps var. orientalis shows 1.436mgN/g. At release test of dead body macrophyte, T-P release rate of Erigeron annuus shows 0.500mgP/g at the top of them and it also shows 0.436mgP/g at Erigeron annuus of living body macrophyte. T-N load of submerged macrophyte shows 0.76% by comparison of total load on watershed and T-P load of that shows 3.61%. In case of removal macrophyte for reduction of pollutant load in submerged area, T-N load of submerged macrophyte changes from 0.76% to 0.15% by comparison of total load on watershed and T-P load of that changes from 3.61% to 0.72%.

• Journal of Korean Society on Water Environment
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• v.20 no.1
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• pp.42-47
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• 2004

This study was accomplished to develope an advanced wastewater treatment process using high MLSS in anoxic tank aimed to improve nutrient removal and to reduce wasting sludge. It was operated with 4 Modes with varing solid concentration and internal recycle ratios. Mode I, II, III was operated 1.0~1.5% MLSS concentration at anoxic tank with 50% sludge recycle rate, however, each internal recycle rate were 100%, 200%, 300% and Mode IV was operated 1.5~2.0% MLSS concentration at anoxic tank with 50% sludge recycle rate and 100% internal recycle rate. The COD removal efficiency didn't show any big difference from Mode I to IV. The average COD removal rate was over than 90%. The T-N removal rate was 73%, the highest rate in all mode. The 36% of SCOD is used for the denitrification and phosphorus release in the anoxic tank. Specific denitrification rate was 3.5mg $NO_3{^-}-N/g$ Mv/hr and denitrification time was 0.7hr. As MLSS concentration is higher in anoxic tank as denitrification time would be shorter. The T-P removal rate was average 70%. The phosphorus release accomplished from the anoxic tank because the anaerobic condition was prevalent in the anoxic due to the prompt completion of denitrification. Sludge production was 0.28 kgVSS/kg $BOD_{removed}$ under the 1.5% MLSS and 17 day SRT. It is prominent result which has 40% sludge reduce comparing with traditional activate sludge system.

• The Korean Journal of Ecology
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• v.26 no.6
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• pp.313-319
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• 2003

Dry weight loss and nutrient release from leaf litter for six tree species were studied using litter bag methods. The litter bags were incubated for f6 months on the forest floor in temperate deciduous forest in Mt. Cheonma, located at the middle part of Korean Peninsula. The changes in nutrient content and the rate of dry weight loss in leaf litter varied with litter types. The litter of Pinus densiflora showed the lowest rate of mass loss (k=0.33), nitrogen concentration (0.89%) and ash concentration (2.50%), while showed the highest C/N ratio (63.40). On the other hand, the litter of Acer pseudo-sieboldianum showed the fastest rate of mass loss (k=0.82), the highest nitrogen concentration (1.11%), and the lowest C/N ratio (49.40). During the decomposition, nitrogen, phosphorus and calcium in the leaf litters showed relatively slow decreasing pattern compared to other elements (carbon, potassium, magnesium, manganese and sodium), but potassium and sodium decreased at early stage of the decomposition for all leaf litters. Differences in annual decomposition rates of litter among species were consistent with the particular chemical characteristics of their leaf litters. The initial concentration of nitrogen was positively correlated with litter decomposition rate for six species, while litter decomposition rate of six species was negatively correlated with C:N ratio of initial leaf litters.

• The Korean Journal of Pharmacology
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• v.28 no.2
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• pp.129-136
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• 1992

As it has been reported that the depolarization-induced acetylcholine (ACh) release is modulated by activation of presynaptic $A_1-adenosine$ heteroreceptor in hippocampus and various lines of evidence indicate the involvement of adenylate cyclase system in $A_1-adenosine$ post-receptor mechanism in hippocampus, it was attempted to delineate the role of adenylate cyclase system in the $A_1-receptor-mediated$ control of ACh release in this study. Slices from rat hippocampus were incubated with $[^3H]-choline$ and the release of the labelled products was evoked by electrical stimulation $(3\;Hz,\;5\;Vcm^{-1},\;2\;ms,\;rectangular\;pulses)$, and the influence of various agents on the evoked tritium-outflow was investigated. $N^6-cyclopentyladenosine$ (CPA), a specific $A_1-adenosine$ receptor agonist, in concentrations ranging from 0.1 to $10\;{\mu}M$, decreased the $[^3H]-ACh$ release in a dose-dependent manner without the changes of basal rate of release. 8-cyclopentyl-1,3-dipropylxanthine $(DPCPX,\;1{\sim}10\;{\mu}M)$, a selective $A_1-receptor$ antagonist, increased the $[^3H]-ACh$ release in a dose-related fashion with slight increase of basal tritium-release. And the CPA effects were significantly inhibited by DPCPX $(2\;{\mu}M)$ pretreatment and the dose-response curve produced by CPA was shifted to the right. The responses to N-ethylmaleimide $(NEM,\;10\;&\;30\;{\mu}M)$, a SH-alkylating agent of G-protein, were characterized by increments of the evoked ACh-release and the basal release, and the CPA effect were completely abolished by NEM pretreatment. Forskolin, a specific adenylate cyclase activator, in concentrations ranging from 0.3 to $10\;{\mu}M$, increased the evoked ACh-release in a dose-dependent manner and the CPA effects were inhibited by forskolin. These results indicate that the $A_1-adenosine$ heteroreceptor plays an important role in ACh-release via nucleotide-binding protein Gi in the rat hippocampus and that the adenylate cyclase system might be participated in this process.

• Applied Chemistry for Engineering
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• v.25 no.5
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• pp.481-486
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• 2014

This study was performed to test combustive properties of medium density fibreboard (MDF) plates treated with piperazinomethyl-bis-phosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), and N,N-dimethylethylenediaminomethyl-bis-phosphonic acid (MDEDAP). MDF specimens were painted three times with 15 wt% solution of the alkylenediaminoalkyl-bis-phosphonic acids at room temperature. After drying specimen treated with chemicals, combustive properties were examined using the cone calorimeter (ISO 5660-1). As a result, combustion-retardation properties increased due to the treatment of bare MDF with alkylenediaminoalkyl-bis-phosphonic acid solution. Especially, the specimens treated with chemicals showed the ignition (TTI) (148 s~116 s) was retarded and the flameout (Tf) (633 s~529 s) time increased, while the total heat release rate (THRR) (61.1~67.0) $MJ/m^2$ was lowered than those of using virgin plate by reducing the burnig rate. Compared with virgin MDF plate, the specimens treated with the alkylenediaminoalkyl-bis-phosphonic acids showed low combustive properties. However the specimens treated with bis-(dimethylaminomethyl) phosphinic acid (DMDP) showed the higher peak heat release rate (PHRR) ($185.08kW/m^2$) than that of the virgin plate.

• Fire Science and Engineering
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• v.27 no.5
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• pp.57-63
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• 2013

This study was performed to test the combustive properties of Pinus rigida plates treated with piperazinomethyl-bisphosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), and N,N-dimethylethylenediaminomethyl- bis-phosphonic acid (MDEDAP). Pinus rigida specimens were painted in three times with 15 wt% alkylenediaminoalkyl- bis-phosphonic acid solutions at the room temperature. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). As a result, the combustion-retardation properties were increased by due to the treated alkylenediaminoalkyl-bis-phosphonic acid solutios in the virgin Pinus rigida. Especially, the specimens treated with chemicals showed both the later time to ignition (TTI) (148-116 s) and longer time to flameout (Tf) (633-529 s) than those of virgin plate by reducing the burnig rate. Compared with virgin pinus rigida plate, the specimens treated with the alkylenediaminoalkyl-bis-phosphonic acids showed partially low combustive properties. However the specimens treated with PIPEABP showed both the higher peak heat release rate (PHRR) (187.56 $kW/m^2$) and higher total heat release rate (THRR) (75.7 $MJ/m^2$) than those of virgin plate.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.156-172
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• 1993

The purpose of this study was to evaluate for the cytotoxicity of root canal sealers - Tubliseal, N2, AH26, and Sealapex - on fibroblasts cultivated from human periodontal ligament. Succinate dehydrogenase activity test and $^{51}Cr$ release test were performed to evaluate the shortterm cytotoxicity. According to l,3 and 6 days vital cell count and $^{14}C$-leucine incorporation rate to fibroblasts were evaluated. The results of this study were as follows: 1. In the test of SDH activity by millipore filter method, Sealapex showed mild cytotoxicity but Tubliseal, N2 and AH26 showed severe cytotoxicity. 2. In $^{51}Cr$ release test, Tubliseal was the most cytotoxic sealer tested, and rank ordered the relative cytotoxicity of the other sealers tested as follows: AH26, N2, Sealapex. 3. In the test of viable cell count, cytotoxicity in Tubliseal was continued because vital cell number reduced with time. Because vital cell was not showed in N2 and AH26 at 1 day, it was recognized that N2 and AH26 exhibited severe cytotoxicity. In Sealapex, vital cell number increased remarkably with time, so it showed that cytotoxicity decreased with time. 4. In $^{14}C$-leucine incorporation rate test, protein sythesis was not produced in Tubliseal, N2 and AH26 after 3 days, it showed that cytotoxicity in Tubliseal, N2 and AH26 was severe. Although protein synthesis in Sealapex decreased with time, it continued after 6 days. Therefore Sealapex has been exhibited mild cytotoxicity.