• Journal of Environmental Science International
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• v.32 no.12
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• pp.899-914
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• 2023

Various seeding materials for cloud seeding are being used, and sodium chloride powder is one of them, which is commonly used. This study analyzed the experimental results of multi-aircraft cloud seeding in connection with Republic of Korea Air Force (CN235) and KMA/NIMS(Korea Meteorological Administration/National Institute of Meteorological Sciences) Atmospheric Research Aircraft. Powdered sodium chloride was used in CN235 for the first time in South Korea. The analysis of the cloud particle size distributions and radar reflectivity before and after cloud seeding showed that the growth efficiency of powdery seeding material in the cloud is slightly higher than that of hygroscopic flare composition in the distribution of number concentrations by cloud aerosol particle diameter (10 ~ 1000 ㎛). Considering the radar reflectivity, precipitation, and numerical model simulation, the enhanced precipitation due to cloud seeding was calculated to be a maximum of 3.7 mm for 6 hours. The simulated seeding effect area was about 3,695 km², which corresponds to 13,634,550 tons of water. In the precipitation component analysis, as a direct verification method, the ion equivalent concentrations (Na⁺, Cl^-, Ca²⁺) of the seeding material at the Bukgangneung site were found to be about 1000 times higher than those of other non-affected areas between about 1 and 2 hours after seeding. This study suggests the possibility of continuous multi-aircraft cloud seeding experiments to accumulate and increase the amount of precipitation enhancement.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.491-499
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• 2023

Scattering by Sea surface roughness occurs due to sea level roughness, communication performance deteriorates by causing frequency spread in communication signals and time variation in communication channels. In order to compare the difference in time variation of underwater acoustic communication channel according to the surface roughness, an experiment was performed in a tank owned by Hanyang University Ocean Acoustics Lab. Artificial surface roughness was created in the tank and communication signals with three bandwidths were used (8 kHz, 16 kHz, 32 kHz). The measured surface roughness was converted into a Rayleigh parameter and used as a roughness parameter, and statistical analysis was performed on the time-varying channel characteristics of the surface path using Doppler spread and correlation time. For the Doppler spread of the surface path, the Weighted Root Mean Square Doppler spread (w_fσ_ν) that corrected the effect of the carrier frequency and bandwidth of the communication signal was used. Using the correlation time of the surface path and the energy ratio of the direct path and the surface path, the correlation of total channels was simulated and compared with the measured correlation time of total channels. In this study, we propose a method for efficient communication signal design in an arbitrary marine environment by using the time-varying characteristics of the sea surface path according to the sea surface roughness.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.85-99
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• 2022

Dryers becoming commercially available for experimental and industrial use are classified to general drying oven, hot-air dryer, vacuum dryer, freezing dryer, etc. and kinds of them are various from the function, size and volume, etc. But the moisture measurement is not applied although it is important factor for the quality control and the performance improvement of products, and then now is very passive because the weight is weighed arbitrarily after dry-end. Generally the method for measuring moisture is divided by a direct measurement method and a indirect measurement method, and the former such as the change of weight or volume on the front and rear of separation of moisture, etc. is mainly used. Relatively a indirect measurement is very limited to apply due to utilize measurement apparatuses using temperature conductivity and micro-wave etc. In this research, we easily designed the moisture measurement system using the open-source based Arduino, and monitored moisture fluctuations and weight profiles in the real-time without the effect of external environment. Concretely the temperature-humidity and load cell sensors were packaged into a drying oven and the various change values were measured, and their sensors capable to operate 60℃ and 80℃ were selected to suitable for the moisture sensitive materials and the food dry. And also the performance safety using the organic samples of banana, pear, sawdust could be secured because the changes of evaporation rate as the dry time and temperature, and the measurement values of load cell appeared stable response characteristics through repeated experiments. Hereafter we judge that the reliability can be improved increasingly through the expansion of temperature-humidity range and the comparative analysis with CFD(Computational Fluid Dynamics) program.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.389-399
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• 2023

Recently, there has been a growing focus on the Entrepreneurial Intention of Chinese College Students as a key driver of motivational behavior. However, previous research has provided limited analysis on the actual impact of Social Support on the Entrepreneurial Intention of Chinese College Students. The purpose of this study is to enhance the Entrepreneurial Intention of Chinese College Students and to ascertain the mediating effect of Career Adaptability in the relationship between Social Support and Entrepreneurial Intention. Zhejiang Province, the top-ranked province in private economy in China, possesses a strong economic development momentum and an innovative entrepreneurial atmosphere. Therefore, this study selected 194 third and fourth-year undergraduate students from universities in Zhejiang Province as participants and collected data through a survey utilizing measures of Social Support, Career Adaptability, and Entrepreneurial Intention. The collected data was analyzed for correlations between the measured variables using SPSS 26 and Stata 17 SEM Builder for quantification and validation. The results of the study revealed that, firstly, while Social Support did not have a direct impact on Entrepreneurial Intention, it was found to have an indirect influence on Entrepreneurial Intention through Career Adaptability and its various sub-variables. Secondly, Social Support among College Students was found to have a positive impact on Career Adaptability. Thirdly, Career Adaptability among College Students was found to have a positive impact on Entrepreneurial Intention. Based on these analytical findings, this study provides theoretical and practical implications as well as fundamental information for entrepreneurship education and Career Adaptability at the university level.

• Journal of fish pathology
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• v.36 no.2
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• pp.337-348
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• 2023

This study was undertaken to evaluate the effect of amprolium hydrochloride on detoxification process of olive flounder Paralichthys olivaceus. A series of two experiment was performed based on the LD₅₀ value obtained for amprolium. First, thirty flounder (average weight 230.27 g; average length 27.99 cm) was randomly allocated into five groups. Treatment was carried out using intra-muscular injection of amprolium at the dose levels of 4, 8, 16, and 32 mg/kg body weight. At 8, 24 and 48 h post injection, liver and kidney were collected for expression assay of drug metabolizing enzymes and pro-inflammatory cytokine genes. We found that the interleukin-1β (IL-1β) mRNA level were induced at 32 mg/kg and CYP1A genes showed the opposite pattern, while UDP-glucuronosyl-transferase (UGT1A7) and GST were significantly reduced in the liver. Moreover, the suppression of drug metabolizing enzymes and cytokine gene in the kidney was observed after treatment. Another treatment was carried out using intramuscular injection with 4, 8, 16, and 32 mg/kg and 60, 80, 100, 120 mg/kg body weight. At 6 days post injection, liver was collected. The IL-1β expression was markedly induced in the experimental group treated with 4 mg/kg. In addition, glutathione S-transferase (GST) mRNA level was higher in the group with 4 mg/kg. In conclusion, our data suggests that amprolium seem to cause direct or indirect physical, or biological toxicity of flounders, although this drug is considered one of the safest synthetic anticoccidial drugs of the livestock industry.

• Journal of Korea Water Resources Association
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• v.56 no.spc1
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• pp.1049-1058
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• 2023

The flow passing through river-crossing structures such as weirs and low-fall dams is dominated by rapidly varied flow including hydraulic jump. The intense unsteadiness of flow velocity and free surface profile affects the stability of such hydraulic structures. In particular, the steady hydraulic jump generated at high Froude number conditions includes remarkably air entrainment, making the flow characteristics more complicated. In this study, a large-eddy simulation was performed for turbulence effect and the hybrid VoF technique to simulate the steady hydraulic jump at the Froude number of 7.3 and the Reynolds number of 15,700. The results of the numerical simulation showed that the instantaneous maximum pressure and time-average pressure distribution calculated on the bottom surface downstream of the structure could be reasonably well reproduced being in good agreement with the experimental values. However, the instantaneous minimum pressure distribution in the direct downstream of the structure shows the opposite pattern to the target experimental measurement value. However, the numerical simulation performed in this study is considered to reasonably predict the minimum pressure distributions observed in various experiments conducted at similar conditions. The vertical distributions of flow velocity and air concentration computed in the center of the hydraulic jump were found to be in good agreement with the experimental results measured under similar conditions, showing self-similarity. These results show that the large eddy simulation and hybrid VoF techniques applied in this study can reproduce the hydraulic jump with strong air entrainment and the resulting intense free surface and pressure fluctuations at high Froude number conditions.

• Journal of The Korean Association For Science Education
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• v.27 no.1
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• pp.18-27
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• 2007

This study examined the influences of cognitive conflict and non-cognitive variables induced by a discrepant event on process of conceptual change, and the processes that a discrepant event lead to situational interest. Seventh graders participated in this study. A preconception test was administered to select students possessing misconceptions about density. The tests of cognitive response and situational interest to a discrepant event were administered. After learning with a CAl program, the tests assessing attention and effort allocated to the CAl, and conceptual understanding were also administered. A path analysis revealed that cognitive conflict induced by a discrepant event caused situational interest, which in turn increased attention and/or effort and thus, resulted in conceptual change. The results of the path analysis on the processes in which a discrepant event led to situational interest suggested that novelty may be a primary source of situational interest. Novelty influenced situational interest directly as well as through attention demand, exploration intention, and instant enjoyment. Moreover, novelty exerted a direct effect on challenge, which in turn had negative effects on instant enjoyment directly as well as through cognitive conflict, and thus, decreased situational interest. However, the path coefficients of the latter were relatively smaller than those of the former. Educational implications are discussed.

• Journal of Ginseng Research
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• v.48 no.3
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• pp.298-309
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• 2024

Background: 20(S)-ginsenoside Rh2(GRh2), an effective natural histone deacetylase inhibitor, can inhibit acute myeloid leukemia (AML) cell proliferation. Lactate regulated histone lactylation, which has different temporal dynamics from acetylation. However, whether the high level of lactylation modification that we first detected in acute promyelocytic leukemia (APL) is associated with all-trans retinoic acid (ATRA) resistance has not been reported. Furthermore, Whether GRh2 can regulate lactylation modification in ATRA-resistant APL remains unknown. Methods: Lactylation and METTL3 expression levels in ATRA-sensitive and ATRA-resistant APL cells were detected by Western blot analysis, qRT-PCR and CO-IP. Flow cytometry (FCM) and APL xenograft mouse models were used to determine the effect of METTL3 and GRh2 on ATRA-resistance. Results: Histone lactylation and METTL3 expression levels were considerably upregulated in ATRA-resistant APL cells. METTL3 was regulated by histone lactylation and direct lactylation modification. Overexpression of METTL3 promoted ATRA-resistance. GRh2 ameliorated ATRA-resistance by downregulated lactylation level and directly inhibiting METTL3. Conclusions: This study suggests that lactylation-modified METTL3 could provide a promising strategy for ameliorating ATRA-resistance in APL, and GRh2 could act as a potential lactylation-modified METTL3 inhibitor to ameliorate ATRA-resistance in APL.

• Korean Journal of Radiology
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• v.23 no.10
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• pp.986-997
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• 2022

Objective: Whether metabolic redistribution occurs in patients with white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) is unknown. This study aimed 1) to propose a measure of the brain metabolic network for an individual patient and preliminarily apply it to identify impaired metabolic networks in patients with WMHs, and 2) to explore the clinical and imaging features of metabolic redistribution in patients with WMHs. Materials and Methods: This study included 50 patients with WMHs and 70 healthy controls (HCs) who underwent ¹⁸F-fluorodeoxyglucose-positron emission tomography/MRI. Various global property parameters according to graph theory and an individual parameter of brain metabolic network called "individual contribution index" were obtained. Parameter values were compared between the WMH and HC groups. The performance of the parameters in discriminating between the two groups was assessed using the area under the receiver operating characteristic curve (AUC). The correlation between the individual contribution index and Fazekas score was assessed, and the interaction between age and individual contribution index was determined. A generalized linear model was fitted with the individual contribution index as the dependent variable and the mean standardized uptake value (SUV_mean) of nodes in the whole-brain network or seven classic functional networks as independent variables to determine their association. Results: The means ± standard deviations of the individual contribution index were (0.697 ± 10.9) × 10^-3 and (0.0967 ± 0.0545) × 10^-3 in the WMH and HC groups, respectively (p < 0.001). The AUC of the individual contribution index was 0.864 (95% confidence interval, 0.785-0.943). A positive correlation was identified between the individual contribution index and the Fazekas scores in patients with WMHs (r = 0.57, p < 0.001). Age and individual contribution index demonstrated a significant interaction effect on the Fazekas score. A significant direct association was observed between the individual contribution index and the SUV_mean of the limbic network (p < 0.001). Conclusion: The individual contribution index may demonstrate the redistribution of the brain metabolic network in patients with WMHs.

• Information Systems Review
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• v.20 no.4
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• pp.59-78
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• 2018

With the advent of the various device types and marketing communication, customer's search and purchase behavior have become more complex and segmented. However, extant research on multichannel marketing effects of the purchase funnel has not reflected the specific features of device User Interface (UI) and User Experience (UX). In this study, we analyzed the marketing channel effects of multi-device shoppers using a unique click stream dataset from global online retailers. We examined device types that activate online shopping and compared the differences between marketing channels that promote visits. In addition, we estimated the direct and indirect effects on visits and purchase revenue through customer's accumulated experience and channel conversions. The findings indicate that the same customer selects a different marketing channel according to the device selection. These results can help retailers gain a better understanding of customers' decision-making process in multi-marketing channel environment and devise the optimal strategy taking into account various device types. Our empirical analyses yield business implications based on the significant results from global big data analytics and contribute academically meaningful theoretical framework using an economic model. We also provide strategic insights attributed to the practical value of an online marketing manager.