• Journal of the Korean Society of Systems Engineering
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• v.17 no.2
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• pp.82-90
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• 2021

The spent fuel pool (SFP) of a nuclear power plant functions to store the spent fuel. The spent fuel pool is designed to properly remove the decay heat generated from the spent fuel. If the cooling function is lost and proper operator action is not taken, the spent fuel in the storage pool can be damaged. Probabilistic safety assessment (PSA) is a safety evaluation method that can evaluate the risk of a large and complex system. So far, the probabilistic safety assessment of nuclear power plants has been mainly performed on the reactor. This study defined the requirements and the functional architecture for the probabilistic safety assessment of the spent fuel pool (SFP-PSA) by applying the systems engineering process. And, a systematic and efficient methodology was defined according to the architecture.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.1
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• pp.61-67
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• 1977

A study was conducted in order to compare the topdressing method of the conventional fertilizers as control and the deep application method of the ball complex fertilizer newly developed. The ball complex fertilizer consisted of 5% of nitrogen, 5% of phosphorus, and 7% of potassium. Basal application of nitrogen for the rice plant was the same for both control plots and ball complex plots. One ball complex fertilizer per four hills was applied at depth of 12~13cm 35days before heading stage while control plot received three times topdressing at different growth stages as usual practice. The results obtained were as follows. 1. The ball complex fertilizer applied in the soil was continuously utilized by the rice plants until harvest time while nitrogen and potassium uptake of control plots was reduced rapidly after heading stage. Daily uptake of nitrogen and potassium per hill at maturing stage were 0.45mg and 0.68mg in control plots, but 4.80mg and 7.0mg respectively in ball complex plots. 2. Dry matter productivity of the rice plant in control plots, well coinciding with nutrients uptake pattern, was maximum just after heading stage decreased at maturing stage. But dry matter productivity in ball complex plots was much higher at maturing stage than at heading stage. 3. Ball complex application increased effective tillering rate, causing higher panicle number per hill. 4. Ball complex application brought about 528kg/10a of hulled grain yield while the conventional practice 423kg/10a. 5. Deep application of ball complex was superior to usual practice in terms of yield components such as panicle number per hill, filled grain number per panicle, maturing rate, and 1,000 grain weight. 6. From the morphological characteristics point of view, the deep application of ball complex made the flag leaf and the 2nd leaf heavier, larger and broader as compared to control treatment. 7. It is considered that by applying the ball complex fertilizer at depth of 12~13cm sufficient amount of nitrogen and potassium could be utilized by rice plants during the maturing stage and assimilated in the leaf blade, consequently making the flag leaf and the 2nd leaf bigger and healthier. The fact can easily explain that the ball complex plots had higher capacity of photosynthesis, less discoloration of lower leaves, bigger leaf area index, and better grain yield as compared to the conventional practice. In conclusion the deep application method of the ball complex fertilizer was superior to the routine topdressing method of the usual fertilizers.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.475-480
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• 2014

In the fields of researches associated with plant layout optimization, the main goal is to minimize the costs of pipelines for connecting equipment. However, what is the lacking of considerations in previous researches is to handle the multi floor processes considering the safety distances for domino impacts on a complex plant. The mathematical programming formulation can be transformed into MILP (Mixed Integer Linear Programming) problems as considering safety distances, maintenance spaces, and economic benefits for solving the multi-floor plant layout problem. The objective function of this problem is to minimize piping costs connecting facilities in the process. However, it is really hard to solve this problem due to complex unequality or equality constraints such as sufficient spaces for the maintenance and passages, meaning that there are many conditional statements in the objective function. Thus, it is impossible to solve this problem with conventional optimization solvers using the derivatives of objective function. In this study, the PSO (Particle Swarm Optimization) technique, which is one of the representative sampling approaches, is employed to find the optimal solution considering various constraints. The EO (Ethylene Oxide) plant is illustrated to verify the efficacy of the proposed method.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.319-325
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• 2015

The safety of plant species used as a source for herbal medicines and dietary supplements has recently been questioned due to poisonings associated with the presence of cadmium (Cd) in these plants. These plants can derive Cd from their presence in the soil. Organic matter (OM) concentrations in soils could affect the availability of Cd for plants. To determine the effect of OM concentration in soil on the concentration of plant available Cd and uptake of this toxic element by medicinal plants, soil and plant samples were collected from 102 fields supporting for 5 species of medicinal plants in 6 province of South Korea. Concentrations of OM and dissolved organic carbon (DOC) in soils affected the phytoavailability of Cd. One M $NH_4OAc$ extractable Cd concentration in soil increased with increasing OM concentrations. There were significantly positive relationships between 1 M $NH_4OAc$ extractable Cd concentration and OM concentration in soil and between 1 M $NH_4OAc$ extractable Cd concentration and DOC concentration. Likewise, OM and DOC concentrations significantly affected Cd concentration in medicinal plant soils. Cadmium concentration in medicinal plants increased with increasing OM concentration in soil [Cd concentration $(mg\;kg^{-1})= 0.179+1.424{\times}10^{-3}$ OM concentrations, $R^2=0.042*$] and with DOC concentration [Cd concentration $(mg\;kg^{-1})= 0.150+5.870{\times}10^{-4}$ DOC concentrations, $R^2=0.124***$]. These results might result from Cd-DOC complex which is easily absorbed Cd form by plant root. Dissolved organic carbon concentration had more positive relationship with Cd concentration in medicinal plants and 1 M $NH_4OAc$ extractable Cd concentration in soils than OM. Cadmium concentration in all 5 species of medicinal plant (Atractylodes macrocephala Koidzumi, Astragalus membranaceus, Codonopsis lanceolata, Platycodon grandiflorum, and Rehmannia glutinosa) significantly increased with increasing DOC concentration in soil. From the above results, formation of Cd-DOC complex caused by OM application might be mainly attributed to increase in Cd concentration in medicinal plants.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.107-120
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• 2017

Bemisia tabaci (Hemiptera: Aleyrodidae) is one of the most important insect pests in the world. In the present study, the taxonomic status of B. tabaci and the number of species composing the B. tabaci complex were determined based on 550 COI gene sequences of B. tabaci. Genetic divergence within B. tabaci ranged from 0% to 27.8% (average 11.1%). This result indicates that the B. tabaci complex is composed of multiple species that may belong to different genera or subfamilies. A phylogenetic tree constructed based on 217 COI gene sequences without duplications revealed that the B. tabaci complex is composed of a total of 43 putative species, including a new species, Java. In addition, genetic divergence within nine species (Australia, Asia II 1, Asia II 6, Asia II 7, Asia II 10, Mediterranean, New world, New world 2, Sub Saharan Africa 1) indicates that 4.0% is reasonable to be used as a threshold of species boundaries within the B. tabaci complex, and species with high intraspecific genetic divergences can be related with cryptic species.

• Journal of Environmental Science International
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• v.24 no.1
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• pp.73-79
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• 2015

The objective of this work was to treat complex mal-odor of food waste with micro-bubbles from enhanced wet scrubber system, where the pilot plant was operated. Micro bubbles from the enhanced reactor of venturi scrubber were successfully generated through the air atomizing process with high velocity more than 60 m/sec and played an important role in the removal of mal-odor. Mal-odor was effectively changed into the micro-bubble and treated with washing chemicals together. Through establishing two series connection of the reactors, 85.2 % removal efficiency of complex mal-odor was obtained in case of average 940 times of input air. 0.35 kg/hr of sulfuric acid, 0.188 kg/hr of sodium hydroxide and 0.043 kg/hr of hypochlorite were injected for chemical washing.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.6
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• pp.87-95
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• 2011

This study investigates Youl Chon Industrial Complex 1 by dividing into three regions : the drainage site, the area inside the complex, and the seaside. Then each region was subdivided into three areas resulting in a total of nine areas for soil sampling and analysis. After analyzing the physical and chemical properties of the soil, all nine area's pH and EC readings indicated that the soil condition is not suitable for vegetation growth (according to the previous study, the pH level was 5.8 and EC was 2.0dS/m). Therefore, for Youl Chon Industrial Complex 1 to become green, the neutralization and reduction of pH and EC level is needed; first, vegetation through dredging soil, and second, introduction of halophytes is suggested. This study finds out that vertical changes in physical and chemical properties of soils in reclaimed sites are very variable and the result depends on surrounding environments, so it suggested the basic data for building vegetation or reclaimed sites. However, the additional study aiming at various reclaimed sites is required as this study was conducted only to limited areas, and this study has left monitoring analysis as the follow-up task to check the relations between a plant community and soils.

• The Korean Journal of Ecology
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• v.19 no.3
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• pp.201-207
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• 1996

Selection of Al tolerant woody plants, and possibility of reforestation with the Al tolerant plants in soil conditions with different Al content, topography and slope exposures were studied on the slopes around Yeocheon Industrial Complex. Root growth in length of plants grown in 1/2 Steinberg solution decreased with increased Al concentrations of the solution. Relative root length showed that Paulownia coreana, Celtis sinensis and Firmiana simplex were sensitive to $500\muM$ Al, Pinus koraiensis, Alnus japonica and Ligustrum japonicum were intermediate, and Pinus rigida, P. densiflora and P. thunbergii were tolerant to $1, 000\muM$ Al. Coniferous plants appeared to be more tolerant to Al than deciduous ones. Soil pH was 4.2 and Al content was 509 ppm in average around the Yeocheon industrial complex. Al content and soil acidity were more deteriorated on the foothill and slope facing to the pollution source from the industrial complex than on the ridge and opposite slope.

• Analytical Science and Technology
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• v.36 no.1
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• pp.44-52
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• 2023

This protocol clarifies a simple and precise method for measuring the activity of xanthine oxidase (XO) enzyme inhibitor. XO enzyme, which accelerates oxidative stress-related disorders through its capacity to generate hydrogen peroxide and superoxide anion radicals (O₂^•-), has been found to be inhibited by several plant extracts. Enzyme samples were incubated with a suitable buffer containing adequate amounts of xanthine as a substrate to determine XO activity. The method depends on direct measurements of uric acid and hydrogen peroxide production to test XO with and without interference. The CUPRAC reagent (Cu(Nc)₂²⁺) was used to inhibit enzyme reaction after incubation was complete. The generated urate and peroxide reduced the Cu(II)-neocuproine complex (Cu(Nc)₂²⁺) to a brightly colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺), which was assessed with a spectrophotometer at 450 nm. XO activity was found to be directly related to the increased absorbance of the colored Cu(I)-neocuproine complex (Cu(Nc)₂⁺). To eliminate catalase enzyme interference, the proposed method used sodium azide and was validated against XO activity using the UV method in matched samples with t-test analysis. The proposed assay can determine XO activity with high precision, as indicated by the correlation coefficient (R² = 0.9935) from comparison with the reference protocol.

• Korean Journal of Plant Taxonomy
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• v.43 no.2
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• pp.118-127
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• 2013

A comparative study of leaf epidermal microstructure in tribes Forsythieae (Abeliophyllum: 1 species, Forsythia: 12 taxa - 10 species, 2 varieties), Fontanesieae (Fontanesia: 2 species) including one related genus Myxopyrum belonging to Myxopyreae (Myxopyrum: 5 taxa - 4 species, 1 subspecies) was carried out using scanning electron microscopy (SEM) in order to evaluate their significance in the taxonomy. The leaves of investigated taxa are either hypostomatic or amphistomatic, but former is more frequent. The size range of the guard cells is 17.14-47.58 ${\times}$ 11.59- 44.25 ${\mu}m$: the smallest one was found in Forsythia giraldiana (17.48-22.96 ${\times}$ 11.64-12.88 ${\mu}m$), while the largest one was measured to Myxopyrum pierrei (31.50-41.75 ${\times}$ 32.53-44.25 ${\mu}m$). Anomocytic stomatal complex are most frequent type (rarely paracytic), usually both anomocytic and anisocytic occur in one leaf. In surface view both adaxial and abaxial anticlinal walls of the subsidiary cells are variable (e.g., straight/curved, undulate, sinuate, undulate/sinuate). Three types (simple unicellular and multicellular non-glandular, subsessile glandular) of trichomes are found in leaves. Finally, the systematic significance of the leaf epidermal micromorphological characters in idenfitication and elucidation of these tribe, between or within the genera including among the species is also briefly discussed.