• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.2
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• pp.135-146
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• 2020

In the strawberry cultivation areas and domestic farms, two-spotted spider mites are the most serious pests. It decreases the product yield due to the direct feeding of chlorophyll by the mites resulting in reduced photosynthetic ability of host plant. In this study, a simplified acaricidal effect evaluation system (SAEES) was employed to choose the effective acaricidal products among 10 items based on leaf-dipping bioassay methods. SAEES had the advantage of being able to screen four commercial products with three replications at the same time in the recommended concentration. The susceptible strains (SL_YS) showed a high mortality rate of about 90-100%, whereas the mortality of local strains was differed by each acaricides. It suggests that the acaricide responses of field populations might differ due to spray frequencies and acaricide product. An efficacy index (0.8-1.0) was determined based on the mortality of susceptible strain, which would allow the most effective commercial products to be selected by the range of this index. In summary, SAEES will enable the selection of effective commercial products and contribute to increasing control against T. urticae in strawberries.

• Journal of Mushroom
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• v.19 no.4
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• pp.279-284
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• 2021

Flammulina velutipes is the representative edible mushroom in Korea. It makes up around 18% of the total mushroom production and accounts for about 36% of the total mushroom export. Despite being one of the most industrially important mushroom in Korea, the distribution rate of domestic cultivar was low (~31.6%) in 2020. Therefore, we need a new domestic cultivar with high quality as the main export mushroom. We developed a new white domestic cultivar, 'Seolhan', bred by mating two monokaryotic strains isolated from Baekseung and Woori-1ho. The optimum mycelial growth temperature was 25℃ and Seolhan had higher mycelial growth than the control at 20 and 25℃. In bottle cultivation, the optimum temperature of incubation was from 15℃ to 17℃ and the growth temperature of Seolhan was 7-8℃, which was slightly higher than that of the control. The yield of Seolan was 226.5±8.0 g, an increase of 18.4% compared to the control. The period of primodia formation also was a couple of days ahead. In morphological traits, the pileus of Seolhan was smaller than that of the control, the stipe was thicker, and the color brighter. As the results of replacement culture and genetic diversity test, it was confirmed that Seolhan was genetically different from other white varieties.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.276-284
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• 2022

In this study, performance evaluation and rheological characteristics were analyzed for recycling the fine powder of nuclear power plant dismantled waste concrete as a solidifying agent for radioactive waste disposal. The radioactive concrete fine powder was used to prepare a simulated sample, and the test specimen was prepared using Di-water, CoCl₂, and 1 mol CsCl aqueous solution as mixing water. Regardless of the aggregate mixing ratio and the type of mixing water, it satisfies the performance standard of 3.45 MPa for compressive strength at 28 days of age. All specimens satisfied the criteria for submersion strength, and the thermal cycle compressive strength satisfies the criteria for all specimens except Plain-50. As a result of evaluating the rheological properties of the solidifying agent, it was found that the increase in the aggregate mixing rate decreased the yield stress and plastic viscosity. The leaching index for cobalt and cesium of all specimens was 6 or higher, which satisfies the standard. In order to secure the stable performance of the solidifying agent, it is considered effective to use 40 % or less of the aggregate component in the solidifying agent.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.477-481
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• 2022

As a part of improving the quality of crude methylnaphthalene (CMNO), this study was experimentally examined the reduction of nitrogen-containing compounds (NC) present in the CMNO by solvent extraction. The CMNO was composed of three kinds of NC [quinolone (QU), iso-quinoline (IQU), indole (IN)], three kinds of bicyclic aromatic compound [BAC; naphthalene (NA), 1-methylnaphthalene (1MNA), 2-methylnaphthalene (2MNA)] and biphenyl (BP) etc., in addition to an aqueous formamide solution, which were used as raw materials and a solvent, respectively. The increase in the volume fraction of water to the solvent in the initial state (y_w,0) caused a sharp decrease in the distribution coefficient and the yield of NC, but conversely raised the increased selectivity of NC based on 2MNA. The compositions of QU, IQU and IN in the raffinate oil recovered through the equilibrium extraction of batch co-current 5-stage under constant conditions [y_w,0 = 0.1, volume fraction of solvent to feed (CMNO) at the initial state = 1, operating temperature = 303 K, liquid-liquid contacting time = 72 h] were reduced by about 51.5%, 55.2%, and 71.8%, respectively, when compared to those of CMNO. From the excellent reduction rate of NC, the formamide extraction method suggested in this study can be expected to be a useful reduction method for NC contained in the CMNO.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.557-566
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• 2022

This study aimed to obtain basic data on high-quality fruit production and efficient cultivation of persimmon cultivar "Godongsi". In the second year of pruning, the number of fruits per tree according to the number of fruit-bearing mother shoots (300, 400, 500, and 700 [control] treatments) was 676.3, 786.0, 866.7, and 1238.7, respectively. Persimmon cultivar "Godongsi" had a decrease in number of fruits per tree and increase in fruit weight as the pruning intensity increased. The average fruit weight in the 300 treatment group was 212.2 g, which was 1.5 times heavier than that in the control. For a high-quality dried persimmon processing, the rate of grade L fruits (170 g<ｘ≤200 g) and over according to the number of fruit-bearing mother shoots was 86.9%, 48.6%, 33.5%, and 8.1%, respectively. The fruit grade of the pruned treatment group was significantly higher than that of the control. Based on the selling price of dried persimmon, the production amount was significantly higher in the 300 treatment than that in the control. When there were many fruits per tree, there was a decrease in quality and increase in cost of harvesting and processing. In conclusion, pruning is essential to increase the fruit quality (fruit weight and grade) of persimmon cultivar "Godongsi". Moreover, the suitable number of fruit-bearing mother shoots was 300.

• Resources Recycling
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• v.31 no.2
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• pp.40-48
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• 2022

In this study, the effects of solution components were investigated in the recovery of vanadium as ammonium metavanadate from vanadium-ore-salt roasting-water leaching solution. The vanadium-containing solution is strongly alkaline (pH 13), so the pH must be lowered to 9 or less to increase the ammonium metavanadate precipitation efficiency. However, in the process of adjusting the solution pH using sulfuric acid, aluminum ions are co-precipitated, which must be removed first. In this study, aluminum was precipitated in the form of an aluminum-silicate compound using sodium silicate, and the conditions for minimizing vanadium loss in this process were investigated. After aluminum removal, the silicate was precipitated and removed by adjusting the solution pH to 9 or less using sulfuric acid. In this process, the concentration and addition rate of sulfuric acid have a significant influence on the loss of vanadium, and vanadium loss was minimized as much as possible by slowly adding dilute sulfuric acid. Ammonium metavanadate was precipitated using three equivalents of ammonium chloride at room temperature from the aluminum-free, aqueous solution of vanadium following the pH adjustment process. The recovery yield of vanadium in the form of ammonium metavanadate exceeded 81%. After washing the product, vanadium pentoxide with 98.6% purity was obtained following heat treatment at 550 ℃ for 2 hours.

• Journal of Naturopathy
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• v.10 no.2
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• pp.86-92
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• 2021

Background: The presence of antioxidants was not confirmed in the medicinal plant Equisetum hyamale grass. Purposes: This study was to determine the antioxidant and elastase inhibition effects of extracts of E. hyemale. Methods: Antioxidant functions of E. hyemale stems and roots were measured and extracted with hot water (HW) and ethyl alcohol (70EOH, 100EOH). Results: The extraction yield of stems was higher in HW extraction than in ethyl alcohol extraction. The polyphenol content was significantly higher in the root extract than in the stem. Total flavonoid content of 70EOH extract was significantly higher in root extract than in stem. The elastase inhibitory function of the extract was 46% in the root and 49% in the stem at 100 ppm of the extract. The ABTS free radical scavenging function was in the order of HW<70EOH<100EOH

• Journal of Mushroom
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• v.20 no.3
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• pp.153-162
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• 2022

The purpose of this study was to breed a variety of stable productivity and high storage characteristics of white Hypsizygus marmoreus, which has high demand at domestic and global market due to a low bitter taste and the preference for white species. Accordingly, 'Baekmaru' was bred by hybridizing brown and white cap color species and backcrossing with white species. The 'Baekmaru' variety was bred by crossbreeding the brown and white species and backcrossing the white species. Through repeated cultivation of 'Baekmaru', a variety with a low contamination rate was selected when culturing the spawn for stable cultivation. As a results of demonstration test, the yield of 'Baekmaru' was 14% higher than that of the commercial variety. In addition, among the fruiting body characteristics of 'Baekmaru', diameter and thickness of the pileus were 16.43±15.27mm and 6.46±0.58mm, which were slightly higher than the commercial variety, and the hardness was 2.69±0.89N for the pileus and 3.09±0.89N for the stipe. The shelf life showed less change in thickness and color of pileus compared to commercial variety. The hardness of pileus of 'Baekmaru' was maintained in the range of 3.5 to 4.0N in the 4℃ and 4℃ and 20℃ mixed treatment until 30 days of storage, and was higher than that of the commercial variety. Therefore, it was suggested to be excellent in storability.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.25 no.4
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• pp.1-13
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• 2022

This study was conducted to investigate the chlorophyll content, photosynthetic characteristics, and growth characteristics of Aster koraiensis and Dendranthema zawadskii var. latiloba according to shading treatment. A. koraiensis and D. zawadskii grew in four different shading treatment plots (0%, 50%, 75% and 95% of full sunlight) for experiments. It was found that as the shading level increased, the total chlorophyll content increased and dark respiration decreased in both A. koraiensis and D. zawadskii, indicating that A. koraiensis and D. zawadskii increase the utilization efficiency for photosynthesis under low light conditions. In addition, as the shading level increased, the net apparent quantum yield increased, resulting in the highest in the 95% shading plot, but the highest photosynthetic rate, water use efficiency, and leaf mass per area (LMA) were shown in the control group than in the shading treatments. The results showed that A. koraiensis and D. zawadskii are heliophytes showing plasticity to light, and if the light is restricted to continue to shade, it may be detrimental to growth. For healthy growth, it is considered suitable to grow A. koraiensis under full light conditions, and D. zawadskii under the light condition that blocks 0-50% of full sunlight.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.34-39
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• 2023

Growth modeling in plant factories can not only control stable production and yield, but also control environmental conditions by considering the relationship between environmental factors and plant growth rate. In this study, using the expolinear function, we modeled perilla [Perilla frutescens (L.) Britt.] cultivated in a plant factory. Perilla growth was investigated 12 times until flower bud differentiation occurred after planting under light intensity, photoperiod, and the ratio of mixed light conditions of 130 μmol·m^-2·s^-1, 12/12 h, red:green:blue (7:1:2), respectively. Additionally, modeling was performed to predict dry and fresh weights using the expolinear function. Fresh and dry weights were strongly positively correlated (r = 0.996). Except for dry weight, fresh weight showed a high positive correlation with leaf area, followed by plant height, number of leaves, number of nodes, leaf length, and leaf width. When the number of days after transplanting, leaf area, and plant height were used as independent variables for growth prediction, leaf area was found to be an appropriate independent variable for growth prediction. However, additional destructive or non-destructive methods for predicting growth should be considered. In this study, we created a growth model formula to predict perilla growth in plant factories.