• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.472-489
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• 2023

This study was conducted to derive the optimal estimation equations for deriving the green and dry weights of Larix kaempferi (Japanese larch) and Pinus rigida (Rigida pine), which are major coniferous tree species in South Korea. The equations were then used to develop weight tables. Table development began with the sampling of 150 L. kaempferi and 90 P. rigida trees distributed throughout the national scale, after which green weights were measured on-site. Samples from each stand were then collected, and their dry weights were measured in a laboratory. The equation used to calculate green and dry weights was divided into a one-variable formula that uses only the diameter at breast height (DBH) and a two-variable equation that employs DBH and height. The equations used to estimate the green and dry weights of logs were divided into one- and two-variable equations using DBH. Statistical data, such as the fitness index (FI), root mean square error, standard error of estimation, and residual diagram, were used to verify the suitability of the estimation equations. Applicability was examined by calculating weights using the derived optimal equations. The equation W = bD+cD² was used in measurements involving only DBH, whereas the equation W = aD^bH^c was employed in cases involving both diameter and height at breast height. The FI of W = bD+cD² was 0.91, while that of W = aD^bH^c was 0.95, both of which are high values. With these estimation formulas, weight tables for the green and dry weights of L. kaempferi and P. rigida were prepared and compared with weight tables created 20 years ago. The green and dry weight tables of both species were larger.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.142-150
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• 2023

As global warming continues, the time of invasion of Spodoptera frugiperda has been advanced and the inflow rate has been increasing, leading to great increases in damage to crops. In this study, in order to minimize crop damage caused by S. frugiperda, the control period was set for corn fields through control thresholds, and the control effects according to the chemical spraying methods were investigated in forage corn filed. Even under the condition of 4% injury level during the corn silking stage, the damage rate of ear was 70%, showing an aspect of extensive damage. The economic injury level of S. frugiperda second instar larvae was shown to be 0.7 larvae per stalk, and the control threshold level was shown to be 0.6 larvae. The income was calculated by applying the corn wholesale unit price, and according to the result, even under the condition of injury level of 4%, there was a loss of KRW 895,221/10a, and the higher the injury level, the greater the decrease in income. To control S. frugiperda, the insecticidal effects of 10 single formulations registered for S. frugiperda were tested, and according to the results, four types(emamectin benzoate, chlorantraniliprole, indoxacarb, and spinetoram) showed high insecticidal activity not lower than 93.3%, and three types (chloran- traniliprole, spinetoram, and indoxacarb) were considered to be effective in controlling S. frugiperda as they showed high residual effects through insecticidal effect persistence tests. Therefore, conventional control and aerial control were conducted twice at 7-day intervals with indoxacarb SC and chlorantraniliprol WP, which show high activity against S. frugiperda, respectively, prior to the silking of forage corn. As a result, conventional control showed higher control values, 46.3%p in the case of indoxacarb SC and 21.7%p in the case of chlorantraniliprol WP, than aerial control through the primary control. In the secondary control too, higher control values of 26.7%p in the case of indoxacarb SC and 40.4%p in the case of chlorantraniliprol WP were found in conventional control than in aerial control. Therefore, it is considered necessary to prepare measures to improve the control effects in the recent situation where alternative methods for manpower control are widely used.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.4
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• pp.315-327
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• 2007

This study investigated temporal and spatial variation of Pb and stable Pb isotopes accumulated in Ulleung Basin core sediments (4) using MC ICP/MS in order to identify the sources of anthropogenic Pb in the East/Japan Sea. Leached (1M HCl) Pb concentration and isotope ratios ($^{207}Pb/^{206}Pb\;and\;^{208}Pb/^{206}Pb$) were nearly constant during 300 yrs past than 1930, but increased up to twice in concentration and as much as 3.41% (1.70%) after 2000. On the other hand, residual Pb concentrations were nearly constant for past 400 yrs. The accumulation rates of anthropogenic Pb in the basin area were in the range of $3.1-3.5mg/m^2/yr$, which were similar levels to total atmospheric Pb deposition fluxes from 1990s to the present. In the slope area, more increase of anthropogenic Pb accumulation than the levels expected from mass accumulation rate could be found after the middle of 1990s. From the detailed evaluation for the temporal and spatial variation of accumulation rate and isotope ratios of anthropogenic Pb, we proposed probable sources and pathways of anthropogenic Pb. Pb emmision by coal burning from the China and Korea initiated the accumulation of anthropogenic Pb in the sediments of East/Japan Sea from 1930s. The accumulation of Pb increased by the addition of anti-nocking agents from both countries untill the beginning of 1990s, but from the middle of 1990s to the present, the phase-out of gasoline additives and the rapid increase of coal burning from the China maintained the atmospheric Pb levels in the Ulleung basin nearly similar to before. However, the local sources within this basin might take an important role in the rapid increase of anthropogenic Pb accumulation in slope areas from the middle of 1990s.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.99-107
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• 2024

Along with economic growth and industrial development, there is an increasing demand for various electronic components and device production of semiconductor, SMT component, and electrical battery products. However, these products may contain foreign substances coming from manufacturing process such as iron, aluminum, plastic and so on, which could lead to serious problems or malfunctioning of the product, and fire on the electric vehicle. To solve these problems, it is necessary to determine whether there are foreign materials inside the product, and may tests have been done by means of non-destructive testing methodology such as ultrasound ot X-ray. Nevertheless, there are technical challenges and limitation in acquiring X-ray images and determining the presence of foreign materials. In particular Small-sized or low-density foreign materials may not be visible even when X-ray equipment is used, and noise can also make it difficult to detect foreign objects. Moreover, in order to meet the manufacturing speed requirement, the x-ray acquisition time should be reduced, which can result in the very low signal- to-noise ratio(SNR) lowering the foreign material detection accuracy. Therefore, in this paper, we propose a five-step approach to overcome the limitations of low resolution, which make it challenging to detect foreign substances. Firstly, global contrast of X-ray images are increased through histogram stretching methodology. Second, to strengthen the high frequency signal and local contrast, we applied local contrast enhancement technique. Third, to improve the edge clearness, Unsharp masking is applied to enhance edges, making objects more visible. Forth, the super-resolution method of the Residual Dense Block (RDB) is used for noise reduction and image enhancement. Last, the Yolov5 algorithm is employed to train and detect foreign objects after learning. Using the proposed method in this study, experimental results show an improvement of more than 10% in performance metrics such as precision compared to low-density images.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.29 no.2
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• pp.77-100
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• 2024

Circulation, tides, currents, harmful algal blooms, water quality, and hypoxic conditions in Jinhae-Masan Bay have been extensively studied. However, these previous studies primarily focused on short-term variations, and there was limited detailed investigation into the physical mechanisms responsible for ocean circulation in the bays. Oceanic processes in the bays, such as pollutant dispersal, changes on a seasonal time scale. Therefore, this study aimed to understand how the circulation in Jinhae-Masan Bay varies seasonally and to examine the effects of tides, winds, and river discharges on regional ocean circulation. To achieve this, a three-dimensional ocean circulation model was used to simulate circulation patterns from 2016 to 2018, and sensitivity experiments were conducted. This study reveals that convective estuarine circulation develops in Jinhae and Masan Bays, characterized by the inflow of deep oceanic water from the Korea Strait through Gadeoksudo, while surface water flows outward. This deep water intrusion divides into northward and westward branches. In this study, the volume transport was calculated along the direction of bottom channels in each region. The meridional water exchange in the eastern region of Jinhae Bay is 2.3 times greater in winter and 1.4 times greater in summer compared to that of zonal exchange in the western region. In the western region of Jinhae Bay, the circulation pattern varies significantly by season due to changes in the balance of forces. During winter, surface currents flow southward and bottom currents flow northward, strengthening the north-south convective circulation due to the combined effects of northwesterly winds and the slope of the sea surface. In contrast, during summer, southwesterly winds cause surface seawater to flow eastward, and the elevated sea surface in the southeastern part enhances northward barotropic pressure gradient intensifying the eastward surface flow. The density gradient and southward baroclinic pressure gradient increase in the lower layer, causing a strong westward inflow of seawater from Gadeoksudo, enhancing the zonal convective circulation by 26% compared to winter. The convective circulation in the western Jinhae Bay is significantly influenced by both tidal current and wind during both winter and summer. In the eastern Jinhae Bay and Masan Bay, surface water flows outward to the open sea in all seasons, while bottom water flows inward, demonstrating a typical convective estuarine circulation. In winter, the contributions of wind and freshwater influx are significant, while in summer, the influence of mixing by tidal currents plays a major role in the north-south convective circulation. In the eastern Jinhae Bay, tidally driven residual circulation patterns, influenced by the local topography, are distinct. The study results are expected to enhance our understanding of pollutant dispersion, summer hypoxic events, and the abundance of red tide organisms in these bays.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.4
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• pp.13-28
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• 2023

This study assessed the biochemical methane potential (B_u-P) of three grass species-Poa pratensis (PP), Zoysia japonica (ZJ), and Agrostis stolonifera (AS). B_u-P values were determined as 0.330 Nm³/kg-VS_added for PP, 0.297 Nm³/kg-VS_added for ZJ, and 0.261 Nm³/kg-VS_added for AS. Notably, PP exhibited superior suitability for methane production. The investigation also examined the impact of silage storage duration on PP grass clippings, revealing a 19% decline in B_u-P from an initial value of 0.269 Nm³/kg-VS_added on day 0 to 0.217 Nm³/kg-VS_added on day 180. Throughout the storage period, there were significant increases in neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) contents, rising from 67.59%, 39.68%, and 3.02% on day 0 to 77.12%, 54.65%, and 6.24% on day 180, respectively. These findings highlight the influence of storage duration on the anaerobic digestibility of PP grass clippings. To effectively utilize grass clippings as a renewable resource for methane production, further studies considering factors such as initial moisture content, pretreatment methods, and potential effects of residual pesticides are necessary to optimize anaerobic digestion efficiency for herbaceous biomass.

• Korean Journal of Clinical Laboratory Science
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• v.56 no.2
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• pp.147-155
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• 2024

Gallium-68-prostate-specific membrane antigen-11 (⁶⁸Ga-PSMA-11) is a positron emission tomography radiopharmaceutical that labels a Glu-urea-Lys-based ligand with ⁶⁸Ga, binding specifically to the PSMA. It is used widely for imaging recurrent prostate cancer and metastases. On the other hand, the preparation and quality control testing of ⁶⁸Ga-PSMA-11 in medical institutions takes over 60 minutes, limiting the daily capacity of ⁶⁸Ge/⁶⁸Ga generators. While the generator provides 1,110 MBq (30 mCi) nominally, its activity decreases over time, and the labeling yield declines irregularly. Consequently, additional preparations are needed, increasing radiation exposure for medical technicians, prolonging patient wait times, and necessitating production schedule adjustments. This study aimed to reduce the ⁶⁸Ga-PSMA-11 preparation time and optimize the automated synthesis system. By shortening the reaction time between ⁶⁸Ga and the PSMA-11 precursor and adjusting the number of purification steps, a faster and more cost-effective method was tested while maintaining quality. The final synthesis time was reduced from 30 to 20 minutes, meeting the standards for the HEPES content, residual solvent EtOH content, and radiochemical purity. This optimized procedure minimizes radiation exposure for medical technicians, reduces patient wait times, and maintains consistent production schedules, making it suitable for clinical application.

• Journal of Life Science
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• v.34 no.7
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• pp.485-492
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• 2024

Sea cucumbers contain more than 50% protein in their solid content, and they also possess various bioactive substances such as saponins and mucopolysaccharides. This study analyzed the activities of various enzymes derived from Bacillus and lactic acid bacteria and determined to degrade the components of sea cucumbers. Among the analyzed strains, B. subtilis K26 showed the highest activities in protease and xylanase and relatively high activity in cellulase. Accordingly, samples of sea cucumber and water were mixed in equal proportions, sterilized, and then fermented by inoculating them with B. subtilis K26. Following this, a higher amino acid content was observed between 1.5 and 7.5 hr, a lower residual solid content in this time, and a lesser fermentation odor. The saponin content in fermented sea cucumber powder extracted with butanol was measured to be 1.12 mg/g. The chondroitin sulfate content was evaluated to be 5.11 mg/g in raw sea cucumber. The total polyphenol content, flavonoid content, and antioxidant activities were 6.95 mg gallic acid equivalent/g, 3.69 mg quercetin equivalent/g, and 3.69 mg quercetin equivalent/g in raw sea cucumber, respectively. Moreover, the DNA damage protective effect of fermented sea cucumber extract was found to be concentration-dependent, with a very strong effect at very low concentrations. Overall, we suggest that sea cucumber fermented with B. subtilis K26 has a high potential as a food for inhibiting oxidation, enhancing immunity, and improving muscle function in the human body thanks to its high free amino acid content.

• Food Science and Preservation
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• v.31 no.2
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• pp.267-275
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• 2024

Artemisia fukudo Makino belongs to the Asteraceae family, is a halophyte that can grow in salinity soils and is known for its various physiological activities. However, few studies were comparing it according to the growth environment. Therefore, in this study, we analyzed the antioxidant activity, functional ingredients, and safety of Artemisia fukudo Makino according to the growth environment. Total polyphenol content was the highest in native mature leaves, but 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity was higher in cultivated leaves than in native leaves. The total mineral content, excluding sodium, was higher in cultivated than in native leaves. The content of potassium and calcium was higher in cultivated leaves than in native leaves. In addition, heavy metal analysis showed that cultivated leaves were generally lower than those of native leaves. Residual pesticides were not detected in all samples. In conclusion, since there is no significant difference in cultivated leaves compared to native leaves, it was judged that cultivated leaves could be used as a variety to be grown and mass-produced.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.484-497
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• 2024

Neonicotinoid pesticides, widely used worldwide as potent insecticides, have been found to have detrimental effects on the environment and living organisms due to their persistent residues. This study aimed to investigate the neonicotinoid pesticides, imidacloprid, and clothianidin, focusing on their impact on honey bee toxicity and foliar residue levels. Alfalfa was selected as control crop while bell peppers, and cucumbers were chosen as representative application crops, respectively. The investigation involved comparing the toxicity and foliar residue levels resulting from soil and foliar treatments, with a focus on identifying potential shortcomings in conventional foliar residue toxicity testing methods. Imidacloprid and clothianidin were applied to crops or soil at recommended rates and through irrigation. The honey bee mortality rate (RT₂₅) over time was determined, and pesticide residues on leaves were quantified using High-Performance Liquid Chromatography (HPLC). The results revealed that foliar treatment with imidacloprid on alfalfa resulted in an RT₂₅ of less than 1 day, with residues ranging from 1.07 to 19.27 mg/kg. In contrast, application on bell peppers showed RT₂₅ within 9 days, with residues ranging from 1.00 to 45.10 mg/kg. Clothianidin foliar treatment displayed RT₂₅ within 10 days on alfalfa, with residues between 0.61 and 2.57 mg/kg. On bell peppers, RT₂₅ was within 28 days, with residues ranging from 0.13 to 2.85 mg/kg. Soil treatment with imidacloprid and clothianidin in alfalfa exhibited minimal impact on honey bees and residues of 0.05 to 0.37 mg/kg. However, in applied crops, imidacloprid showed RT₂₅ within 28 days and residues ranging from 4.47 to 130.43 mg/kg, while clothianidin exhibited RT₂₅ within 35 days and residues between 5.96 and 42.32 mg/kg. In conclusion, when comparing honey bee toxicity and foliar residues among crops, application crops had a more significant impact on honey bee mortality and higher residue levels compared to control crops. Moreover, soil treatment for application crops resulted in higher RT₂₅ and residue levels compared to foliar treatment. Therefore, to ensure pesticide safety and environmental sustainability, diverse research approaches considering different crops and application methods are necessary for the safety assessment of imidacloprid and clothianidin.