• Resources Recycling
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• v.32 no.1
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• pp.50-59
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• 2023

The amount of dust generated during the dissolution of scrap in an electric arc furnace is approximately 1.5% of the scrap metal input, and it is primarily collected in a bag filter. Electric arc furnace dust primarily consists of zinc and ion. The processing of zinc starts with its conversion into pellet form by the addition of a carbon-based reducing agent(coke, anthracite) and limestone (C/S control). These pellets then undergo reduction, volatilization, and re-oxidation in rotary kiln or RHF reactor to recover crude zinc oxide (60%w/w). Next, iron is discharged from the electric arc furnace dust as a solid called Fe clinker (secondary by-product of the Fe-base). Several methods are then used to treat the Fe clinker, which vary depending on the country, including landfilling and recycling (e.g., subbase course material, aggregate for concrete, Fe-source for cement manufacturing). However, landfilling has several drawbacks, including environmental pollution due to leaching, high landfill costs, and wastage of iron resources. To improve Fe recovery in the clinker, we pulverized it into optimal -sized particles and employed specific gravity and magnetic force selection methods to isolate this metal. A carbon-based reducing agent and a binding material were added to the separated coarse powder (>10㎛) to prepare briquette clinker. A small amount (1-3%w/w) of the briquette clinker was charged with the scrap in an electric arc furnace to evaluate its feasibility as an additives (carbonaceous material, heat-generating material, and Fe source).

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.424-431
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• 1995

This study was conducted to evaluate resistance and physiological responses of Zelkova serrata Makino seedlings to ozone in open-top chamber. One-year-old seedlings of Zelkova serrata were planted in pots in April and grown in greenhouse until August. The plants were transferred into two out-door open-top chambers with a dimension of 2.0 m in diameter and 2.0 m in height. First chamber served as a control and was supplied with ambient air. Ozone was added to the second chamber for 5 hours per day(10.00 AM-15.00 PM) for 23 consecutive days at 0.1 ppm. Each chamber housed 70 pots. Every two, three or five days after initiation of exposure, ten pots were randomly removed from the chamber and determined for the contents of chlorophyll a, b, total chlorophyll and ${\beta}$-carotene in the leaves. Photosynthesis and dark respiration were estimated by measuring $CO_2$ absorption in a gas exchange chamber and oxygen absorption by oxygen monitoring system, respectively. Superoxide dismutase(SOD) activity in the leaves was assayed by a xanthine oxidase method. First visible injury of translucent(water-soaked looking) spots appeared on the leaves 14 days after the initial exposure, and ozone accelerated senescence of old leaves. Contents of chlorophyll a and b decreased by 17%, and 31%, respectively, in ozone treatment two days after exposure. The decrease in chlorophyll b was greater than that of chlorophyll a. Content of ${\beta}$-carotene in ozone treatment decreased by 25% two days after initiation of exposure, but the reduction was recovered with time. Photosynthesis decreased by 45%, and the respiration increased by 28% in the ozone treatment. SOD activity started to increase 4 days after beginning of exposure and increased by 285% 7 days after exposure, and decreased to the level below the control treatment with the advancement of the visible injury.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.89-97
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• 2020

This experiment was conducted at Sancheong from 2013 to 2015. The objective of this study was to establish the seeding rate, and to clarify the optimum nitrogen fertilizer level for rye seed production in the southern area of Korea. We employed Korean rye cultivar 'Gogu' in this test. The experimental design was a split-plot design with three replications. A split-plot design was used with three seeding levels (3, 5, and 7 kg 10 a^-1) on the main plots and other treatments fully randomized in sub-plots. A factorial arrangement of treatments included three different nitrogen fertilizer levels (0, 3, 6, and 9 kg 10 a^-1). The grain yields of rye affected by increasing the seeding rate. The number of spike per m² and immature grain weight was increasing, while the fertility rate and the number of grain per spike were decreased as seeding rate were increased from 3 kg 10 a^-1 to 7 kg 10 a^-1. The percentage of a productive tiller, 1-liter weight, and 1000-grain weight also decrease by increasing seeding but the grain yields of rye had less effect. There was an increase in the number of spike per m², the number of grain per spike, and grain yields as nitrogen fertilizer level was increased from 0 kg 10 a^-1 to 9 kg 10 a^-1 and followed a delaying heading and an increasing lodging of the plant. But grain yields did not affected by the interaction of seeding rate × nitrogen fertilizer levels. The best seeding rate and nitrogen fertilizer level for rye seed production were 5 kg and 3 kg 10 a^-1, respectively, considering seed and fertilizer reduction and the prevention of pollution by excess fertilization.

• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.481-493
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• 2023

In high-density urban areas, the urban heat island effect increases urban temperatures, leading to negative impacts such as worsened air pollution, increased cooling energy consumption, and increased greenhouse gas emissions. In urban environments where it is difficult to secure additional green spaces, rooftop greening is an efficient greenhouse gas reduction strategy. In this study, we not only analyzed the current status of the urban heat island effect but also utilized high-resolution satellite data and spatial information to estimate the available rooftop greening area within the study area. We evaluated the mitigation effect of the urban heat island phenomenon and carbon sequestration capacity through temperature predictions resulting from rooftop greening. To achieve this, we utilized WorldView-2 satellite data to classify land cover in the urban heat island areas of Busan city. We developed a prediction model for temperature changes before and after rooftop greening using machine learning techniques. To assess the degree of urban heat island mitigation due to changes in rooftop greening areas, we constructed a temperature change prediction model with temperature as the dependent variable using the random forest technique. In this process, we built a multiple regression model to derive high-resolution land surface temperatures for training data using Google Earth Engine, combining Landsat-8 and Sentinel-2 satellite data. Additionally, we evaluated carbon sequestration based on rooftop greening areas using a carbon absorption capacity per plant. The results of this study suggest that the developed satellite-based urban heat island assessment and temperature change prediction technology using Random Forest models can be applied to urban heat island-vulnerable areas with potential for expansion.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.110-117
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• 2016

Litter fall is a source of nutrients and carbon transfer in terrestrial ecosystems. Litter decomposition provides nutrients needed for plant growth, sustains soil fertility, and supplies $CO_2$ to the atmosphere. We collected the leaf litter of evergreen broadleaf tree, Camellia japonica L., and carried out a decomposition experiment using the litterbag method in Ju-do, Wando-gun, Korea for 731 days from Dec 25, 2011 to Dec 25, 2013. The leaf litter of C. japonica remained 42.6% of the initial litter mass after experiment. The decay constant (k) of C. japonica leaf litter was $0.427yr^{-1}$. The carbon content of C. japonica leaf litter was 44.6%, and the remaining carbon content during the decomposition tended to coincide with the changes in litter mass. The initial nitrogen and phosphorus content was 0.47% and 324.7 mg/g, respectively. The remaining N in decaying litter increased 1.66-fold in the early decomposition stage, then gradually decreased to 1.18-fold after 731 days. The content of P showed the highest value (1.64-fold of initial content) after 456 days, which then fell to a 1.15-fold after 731 days. The remaining Ca, K, Mg and Na content in C. japonica leaf litter tended to decrease during decomposition. The remaining K showed a remaining mass of 8.9% as a result of rapid reduction. The initial C/N and C/P ratio of C. japonica leaf litter was 94.87 and 1368.5, respectively. However, it tended to decrease as decomposition progressed because of the immobilization of N and P (2.78 and 2.68-fold of initial content, respectively) during the leaf litter decaying. The study results showed that N and P was immobilized and other nutrients was mineralized in C. japonica leaf litter during experimental period.

• Korean Journal of Poultry Science
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• v.31 no.4
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• pp.229-235
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• 2004

A study was conducted to examine the effect of dietary supplementation of multiple probiotics (EM) on growth performance, blood cholesterol, intestinal micro flora, and fecal gas emission in broiler chicks. A total of 450 one day old male broiler chicks (Ross $\times$ Ross) were divided into six treatments with five replications in each treatment for five weeks. Treatments were factorially designed with two levels of diet containing probiotics (DW; 0, $0.2\%$) and three levels of drinking water containing probiotics (DW; 0, 0.01, $0.1\%$). Basal diets contained $21.5\%$ CP and 3,100 kcal/kg ME for starting and $19\%$ CP and 3,100 kcal/kg ME for finishing period. Weight gain, feed intake, and feed conversions of birds fed with probiotics were not significantly different between Ds. Total cholesterol and triglyceride levels were significantly lower (P<0.05) in birds fed with DW $0.01\%$ or $0.1\%$ compared with no probiotics group, but there was no significant difference between D treatments. The number of E. coli, Salmonella and Lactobacillus in the ileum and cecum of the birds fed multiple probiotics were not significantly different from those of no probiotic groups. There were no significant differences in the $CO_2$ gas emissions of fecal between birds fed with Ds or among birds fed with DW. However, $NH_3$ gas emissions of DW $0.1\%$ were significantly lower (P<0.05) than DW $0\%$. In the results of this study, supplementation of probiotics tended to decrease the serum cholesterol and triglyceride compared to those of control groups and reduction of fecal $NH_3$ gas emission.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.725-733
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• 2012

Effects of postharvest 1-methylcyclopropene (1-MCP) treatment, controlled atmosphere (CA) storage, and shelf temperature on quality of 'Gamhong' apples were analyzed during export simulation. Fruits were harvested at the optimum maturity for long-term storage, treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP for 16 hours, and then stored for 6 months under air and CA conditions at $0^{\circ}C$. Poststorage export procedure was performed by applying additional 2-week refrigerated storage and 7-day shelf-life test at 7 and $20^{\circ}C$, which simulated container shipment and local distribution, respectively. After storage and during export simulation, rates of respiration and ethylene evolution were significantly lower in 1-MCP treated and CA-stored apples. For the reduction of respiration, CA storage was more effective than 1-MCP treatment. Soluble solids content was maintained higher in 1-MCP treated apples, while titratable acidity was maintained better both in the 1-MCP treated and CA-stored apples. Effects of 1-MCP treatment and CA storage were highly significant in maintaining flesh firmness and sensory texture ratings. Additive effects from combined application of 1-MCP treatment and CA storage were occasionally observed. Shelf temperature during the local distribution simulation seemed not to significantly influence quality changes only showing limited effects on flesh firmness. Overall results suggest that storage potential of 'Gamhong' apples is shorter than 4 months in control fruit under refrigerated air conditions, whereas the potential can be extended to longer than 6 months by 1-MCP treatment and CA storage. Postharvest program should be provided considering the time of export, i.e. period of storage, and duration of local distribution.

• KDI Journal of Economic Policy
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• v.34 no.2
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• pp.55-93
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• 2012

In Korea, energy policies are actualized through various energy-related plans. Recently, however, as high-ranking plans, which are very vision-oriented, continually set higher sector-by-sector goals, subordinate action plans, which require consistency, encounter distortions in their establishment process. Also, each subordinate action plan reveals limitations in terms of securing flexibility of the plan in responding to uncertainties of the future. These problems pose potential risks such as causing huge social costs. In this regard, with an aim to provide empirical evidence for discussions on improving the procedure for developing and executing Korea's energy plans, this study mainly analyzes the Basic Plan on Electricity Demand and Supply-one of the most important subordinate action plans-in order to explain the problems of the Basic Plan in a logical manner, and potential problems that could occur in the process of sustaining consistency between the Basic Plan and its higher-ranking plans. Further, this paper estimates the scale of social costs caused by those problems assuming realistic conditions. According to the result, in the case of where maximum electric power is estimated to be 7% (15%) less than the actual amount in the Basic Plan on Electricity Demand and Supply, the annual generation cost will rise by 286 billion won and (1.2 trillion won) in 2020. Such social costs are found to occur even when establishing and executing the Basic plan according to the target goal set by its higher-ranking plan, the National Energy Master Plan. In addition, when another higher-ranking GHG reduction master plan requires the electricity sector to reduce emissions by additional 5% in the GHG emissions from the right mix in electricity generation with 'zero' cost of carbon emission, the annual generation cost will rise by approximately 915 billion won in 2020. On the other hand, the analysis finds that since economic feasibility of electric powers in Korea varies significantly depending on their type, Korea is expected to face very small potential social costs caused by uncertainties over the future price of carbon dioxide in the process of establishing the Basic Plan.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.853-860
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• 2012

This study investigated the preference and recognition of cooked rice mixed with multigrains. The data for the analysis was collected from 464 people who were residing in Seoul, Gyeongsang and Jeolla area, and analyzed by the SPSS 18.0 program. The result showed that 77.8% of the respondents liked cooked rice mixed with multigrain, showing significant difference by age (p<0.001) and occupation (p<0.01). Of the respondents, 33.8% consumed cooked rice mixed with multigrains at least once a day, showing significant difference by gender (p<0.01), age (p<0.001) and occupation (p<0.001). The most popular type of grains to mix with rice were, in order, black rice (3.8)> brown rice (3.7)> barley (3.7)> proso millet (3.4)> foxtail millet (3.4)> SoRiTae (3.3)> sorghum (3.2)> adlay (3.2)> mung bean (3.1)> buckwheat (3.0)> BacTae (2.8). A total of 32.5% of the respondents answered that 21~30% was proper mixing ratio of multigrains-added cooked rice, showing age (p<0.001), occupation (p<0.001) and resident area (p<0.05). Three or four kinds of grains were preferred to mix cooked rice, showing significant difference by age and occupation (p<0.001). Of the respondents, 43.1% chose price reduction as the most desired improvement of multigrains in the market. Most of the subjects had affirmative view intake of cooked rice mixed with multigrains, but recognized that multigrains were expensive. From these results, this study will provide basic information for the increased availability of multigrains and optimization of the multigrain ratio mix.

• The Korean Journal of Nuclear Medicine Technology
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• v.12 no.1
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• pp.13-18
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• 2008

Purpose: The image processing method due to the algorism which is various portion nuclear medical image decision is important it makes holds. The purpose of this study is it applies hereupon new image processing method SIEMENS (made by Pixon co.) Onco. flash processing reconstruction and the comparison which use the image control technique of existing the clinical usefulness it analyzes with it evaluates. Materials & Methods: 1. Whole body bone scan-scan speed 20 cm/min, 30 cm/min & 40 cm/min blinding test 2. Bone static spot scan-regional view 200 kcts, 400 kcts for chest, pelvis, foot blinding test 3. 4 quadrant-bar phantom-20000 kcts visual evaluation 4. LSF-FWHM resolution comparison ananysis. Results: 1. Raw data (20 cm/min) & processing data (30 cm/min)-similar level image quality 2. Low count static image-image quality clearly improved at visual evaluation result. 3. Visual evaluation by quadrant bar phantom-rising image quality level 4. Resolution comparison evaluation (FWHM)-same difference from resolution comparison evaluation Conclusion: The study which applies a new method Onco. flash processing reconstruction, it will be able to confirm the image quality improvement which until high level is clearer the case which applies the method of existing better than. The new reconstruction improves the resolution & reduces the noise. This enhances the diagnostic capabilities of such imagery for radiologists and physicians and allows a reduction in radiation dosage for the same image quality. Like this fact, rising of equipment availability & shortening the patient waiting move & from viewpoint of the active defense against radiation currently becomes feed with the fact that it will be the useful result propriety which is sufficient in clinical NM.