• Journal of Environmental Science International
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• v.31 no.3
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• pp.247-254
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• 2022

This study investigated the effect of vegetation mat on plant growth and salt reduction in the soil treated with high concentration deicing salt. In order to measure soil chemical characteristics and plant growth, three native groundcover plants (Dendranthema zawadskii var. latilobum, Dendranthema boreale, and Kalimeris yomena) were grown in each of the three plastic containers (50.0 cm width × 35.0 cm length × 8.5 cm deep) with a high concentration treatment of calcium chloride deicing salt. There were two treatments: control, and BVM that combines B (blanket) and VM (vegetation mat). 1,600 g of soil was placed on the top of the drainage layer with 290 g of perlite, 100 seeds each of the three native plants with three repetitions were sowed, and 10 g/L of calcium chloride deicing salt was added in the treatment. As a result of the chemical properties of soil, soil in control treatment was acidic and soil electrical conductivity in BVM was the lowest. Also, exchangeable cations (K⁺, Ca²⁺, Na⁺, and Mg²⁺) in soil and all the three plants were significantly decreased in the BVM treatment. Meanwhile, the germination rate of Dendranthema zawadskii var. latilobum was the highest under high concentration deicing salt in compared to the two plants. Overall, three native groundcover plant growth was higher in the BVM than control treatment significantly. These results suggest that the treatment of blanket vegetation mat has a positive effect on soil and plant growth in soil damaged by deicing salt.

• Safety and Health at Work
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• v.14 no.2
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• pp.215-221
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• 2023

Background: There is little information about the airborne hazardous agents released during the heat treatment when manufacturing a welding material. This study aimed to evaluate the airborne hazardous agents generated at welding material manufacturing sites through area sampling. Methods: concentration of airborne particles was measured using a scanning mobility particle sizer and optical particle sizer. Total suspended particles (TSP) and respirable dust samples were collected on polyvinyl chloride filters and weighed to measure the mass concentrations. Volatile organic compounds and heavy metals were analyzed using a gas chromatography mass spectrometer and inductively coupled plasma mass spectrometer, respectively. Results: The average mass concentration of TSP was 683.1±677.4 ㎍/m³, with respirable dust accounting for 38.6% of the TSP. The average concentration of the airborne particles less than 10 ㎛ in diameter was 11.2-22.8×10⁴ particles/cm³, and the average number of the particles with a diameter of 10-100 nm was approximately 78-86% of the total measured particles (<10 ㎛). In the case of volatile organic compounds, the heat treatment process concentration was significantly higher (p < 0.05) during combustion than during cooling. The airborne heavy metal concentrations differed depending on the materials used for heat treatment. The content of heavy metals in the airborne particles was approximately 32.6%. Conclusions: Nanoparticle exposure increased as the number of particles in the air around the heat treatment process increases, and the ratio of heavy metals in dust generated after the heat treatment process is high, which may adversely affect workers' health.

• Journal of the Korean Society for Heat Treatment
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• v.36 no.6
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• pp.402-411
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• 2023

In order to examine the effect of cementite precipitated on the steel surface on the carburizing rate, the carburizing process was carried out at various boost times to measure the mass gain and carbon flux, phase analysis and carbon concentration analysis were performed on the surface of the carburized specimen. In the case of the only boost type, the longer the boost time, the more the mass gain by the diffused carbon follows the parabolic law and tends to increase. In particular, as the boost time increased, the depth of cementite precipitation and the average size of cementite on the steel surface increased. At a boost time of 7 min, the fraction of cementite precipitated on the surface is 7.32 vol.%, and the carburizing rate of carbon into the surface (surface-carbon flux) is about 17.4% compared to the calculated value because the area of the chemical (catalyst) where the carburization reaction takes place is reduced. The measured carbon concentration profile of the carburized specimen tended to be generally lower than the carbon concentration calculated by the model without considering precipitated cementite. On the other hand, in the pulse type, the mass gain by the diffused carbon increased according to the boost time following a linear law. At a boost time of 7 min, the fraction of cementite precipitated on the surface was 3.62 vol.%, and the surface-carbon flux decreased by about 4.1% compared to the calculated value. As a result, a model for predicting the actual carbon flux was presented by applying the carburization resistace coefficient derived from the surface cementite fraction as a variable.

• Journal of Acupuncture Research
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• v.40 no.4
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• pp.356-367
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• 2023

Background: The aim of this study is to determine the antioxidant and anti-inflammatory effects of Dusokohwaeum (DOE). Methods: To measure the antioxidant and anti-inflammatory effects of DOE, the total flavonoid and polyphenol contents and radical scavenging activity were measured. Furthermore, reactive oxygen species (ROS), nitric oxide, and cytokine production were measured by treating lipopolysaccharide-induced RAW264.7 cells with DOE, and gene expression levels of inducible cyclooxygenase-2, nitric oxide synthase, and cytokines were evaluated. Results: Radical scavenging experiments revealed a significant concentration-dependent increase in scavenging capacity. The production of ROS, nitric oxide, and cytokines in the cells showed a significant concentration-dependent decrease when compared with the control group. The gene expression levels of inducible cyclooxygenase-2, nitric oxide synthase, and cytokines also showed a significant concentration-dependent decrease when compared with the control group. Conclusion: Interestingly, the antioxidant and anti-inflammatory effects of DOE were 23.42 ± 0.64 mg GAE/g and 20.83 ± 0.98 mg QE/g, respectively. The administration of DOE resulted in a concentration-dependent increase in scavenging ability in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging ability experiments. The production of intracellular ROS and nitric oxide was significantly reduced in the presence of DOE. The production of inflammatory cytokines (prostaglandin E2, tumor necrosis factor-alpha [TNF-α], interleukin-1 beta [IL-1β], and IL-6) was significantly reduced in the presence of DOE. Finally, the expression levels of inducible nitric oxide synthase, cyclooxygenase-2, TNF-α, IL-1β, and IL-6 were significantly decreased in the presence of DOE.

• Korean Journal of Optics and Photonics
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• v.35 no.2
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• pp.71-80
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• 2024

We developed a Raman lidar system for remote measurement of carbon dioxide present in atmospheric space. An air-cooled laser with 355-nm wavelength and a 6-inch optical receiver was used to miniaturize the Raman lidar system, and a scanning Raman lidar system was developed using a two-axis scanning device and a photon counter. To verify the performance of the developed Raman lidar system, a gas chamber capable of maintaining a concentration was located at a distance of about 87 m, and the change in Raman signal according to the change in the concentration of carbon dioxide was measured. As a result, it was confirmed that the change in the Raman scattering signal of carbon dioxide that appeared for a change in carbon dioxide concentration from about 0.67 to 40 vol% was linear, and the coefficient of determination (R²) value, which indicates the correlation between the carbon dioxide concentration and Raman scattering signal, showed a high linearity of 0.9999.

• Asia-Pacific Journal of Business
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• v.15 no.3
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• pp.139-172
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• 2024

Purpose - This study investigates the relationship between corporate ownership structure and technological innovation for Chinese listed firms. Specifically, we analyze four ownership characteristics: concentration, constraints, alignment, and foreign/domestic institutional investor ownership, and use patent applications to measure innovation. Design/methodology/approach - Employing a quantitative research design, this study uses panel data of Chinese listed companies during the period from 2015 to 2021. The empirical analysis relies on multiple regression models, including Tobit models and two-stage least squares estimation, to assess the relationship between corporate ownership structure characteristics and innovation. Robustness checks are conducted using lagged dependent variables and subgroup analyses based on firm age, ownership type, and stock exchange listing. Findings - First, it provides empirical evidence on the non-linear relationship between ownership concentration and innovation, suggesting that there is an optimal level of ownership concentration for promoting innovation. Second, it highlights the importance of equity constraints in influencing innovation, showing that both excessive and insufficient equity constraints can hinder innovation. Third, the study demonstrates the negative impact of aligned ownership and control on innovation, suggesting that separation of ownership and control may be beneficial for fostering innovation. Fourth, it sheds light on the differential impact of domestic and foreign institutional investors on innovation, suggesting that foreign institutional investors may play a more positive role in promoting innovation. Research implications or Originality - The significance of this study's results lies in the fact that we empirically analyze the relationship between corporate ownership characteristics and technological innovation, thereby suggesting the direction of a desirable corporate governance structure that listed companies should pursue depending on their circumstances. This research contributes to a deeper understanding of the ownership characteristics that influence technological innovation and provides valuable insights for policymakers and corporate managers.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.6
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• pp.583-592
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• 2016

In this study, we attempt to provide empirical evidence for the effect of the expenditure of the local governments on the air quality management. Based on the statistical data, the concentrations of air pollutants including $PM_{10}$, $O_3$, and $NO_2$ were analyzed in accordance with local characteristics of the local governments' environmental expenditure, demographic characteristics, and economic and human resources between 2008 and 2014. The results showed that government spending is estimated to have insignificant impact on air pollutants concentration. All these results are consistently corroborated from the analysis based on different alternative measure of local governments' expenditure (budget composition and measure of expenditure residuals). Subsequently, this study implies that environmental expenditures of local governments have not been effectively enforced to enhance the air quality of the region in Korea.

• Biomedical Science Letters
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• v.11 no.4
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• pp.435-439
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• 2005

To determine the appropriate concentration of papaverine hydrochloride(PPV) for therapeutic intraarterial infusion against cerebral vasospasm and to measure the mean blood flow velocity of the middle cerebral artery in rabbits. Vasospasm was induced in the experimental groups (3 days after infusion; group 1, n=3, 7 days after infusion; group 2, n=3) and a control group (n=l) by placing a blood clot in the subarachnoid space around the top of the internal carotid siphon. PPV (5 mg/kg) was infused into the internal carotid artery. The vascular diameters of the internal carotid artery (ICA) and middle cerebral artery (MCA) were measured on angiograms before and after infusion. The mean blood flow velocity in the MCA was measured on transcranial doppler sonograms before and 24 hours after infusion. After fixation, the MCA was dissected out, stained, and examined microscopically. After PPV infusion in both groups, vascular dilatation of about $20\%$ was seen. The mean increase in blood flow velocity in the group $1(30\%)$ was smaller than in the group $2(70\%)$. The mean blood flow velocity in the MCA decreased by about $30\%$ in both groups, but increased again after 24 hours nearly to the level before PPV infusion. PPV infusion may be more effective in early stages of vasospasm when vascular walls have fewer histologic changes.

• Journal of the Korea Furniture Society
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• v.21 no.2
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• pp.111-125
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• 2010

The furniture industry in Korea is characterized by its 42.6% of concentration in Gyeonggi Metropolitan area. When taking a look at the representative furniture complexes including Maseok, Ilsan, and Eojeong, the furniture complexes and stores were spontaneously generated at the outskirts of a city whose land cost is relatively cheap. As a consequence, they tend to be jumbled up and face to be moved or contracted forcefully owing to the new town development plan of Metropolitan areas. In contrast, Italia that is one of the advanced country in furniture industry, cultivates and develops furniture complexes in Brianza district by supporting them oriented in the metropolis Milano while hosting large-scale furniture exhibitions. Such attempts have advanced the position of the italian furniture industry into the most leading figure. In this extent, the furniture industry in Korea that is a traditional industry of Gyeonggi Province has to device a political measure and systematic measure for its cultivation as a way to secure the foundation to develop a high value-added product and foster its competitiveness. Such movements are suggested for the development of the furniture industry in Gyeonggi Province.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.7 no.2
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• pp.171-180
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• 1997

The objectives of this study were both 10 discuss the sampling method for airborne metalworking fluids(MWF)' mist and 10 suggest measures to minimize worker's exposure to carcinogen contained in metalworking fluids. In order to measure airborne MWF mist, it seems to be appropriate to use NIOSH Method #0500(filler weight) rather than NIOSH Method # 5026(analysis by FTIR). Because MWF mist on PVC filter evaporated and migrated during sampling, worker's exposure to MWF could be underestimated. So, when evaluating worker's exposure to MWF mist, other environmental conditions also must be considered. Enclosure and local exhaust ventilation system seems to he the most effective measure and must be constructed with process facility. In order to control worker exposure to carcinogens contained in MWF, distillation type and condition for crude oil, PAH concentration in MWF, and viscosity index of MWF must legally be described.