• Journal of Soil and Groundwater Environment
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• v.26 no.5
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• pp.20-28
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• 2021

Perfluorinated compounds(PFCs), an emerging environmental pollutant, are environmentally persistent and bioaccumulative organic compounds that possess a toxic impact on human health and ecosystems. PFCs are distributed widely in environment media including groundwater, surface water, soil and sediment. PFCs in contaminated solid can potentially leach into groundwater. Therefore, understanding PFCs partitioning between the aqueous phase and solid phase is important for the determination of their fate and transport in the environment. In this study, the sorption equilibrium batch and kinetic experiment of PFCs were carried out to estimated the sorption coefficient(K_d) and the fraction between aqueous-solid phase partition, respectively. Sorption branches of the PFDA(Perfluoro-n-decanoic acid), PFNA(Perfluoro-n-nonanoic acid), PFOA(Perfluoro-n-octanoic acid), PFOS(Perfluoro-1-octane sulfonic acid) and PFHxS(Perfluoro-1-hexane sulfonic acid) isotherms were nearly linear, and the estimated K_d was as follow: PFDA(1.50) > PFOS(1.49) > PFNA(0.81) > PFHxS(0.45) > PFOA(0.39). The sorption kinetics of PFDA, PFNA, PFOA, PFOS and PFHxS onto soil were described by a biexponential adsorption model, suggesting that a fast transport into the surface layer of soil, followed by two-step diffusion transport into the internal water and/or organic matter of soil. Shorter times(<20hr) were required to achieve equilibrium and fraction for adsorption on solid(F₁, F₂) increased with perfluorinated carbon chain length and sulfonate compounds in this study. Overall, our results suggested that not only the perfluorocarbon chain length, but also the terminal functional groups are important contributors to electrostatic and hydrophobic interactions between PFCs and soils, and organic matter in soils significantly affects adsorption maximum capacity than kinetic rate.

• Journal of Environmental Science International
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• v.28 no.8
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• pp.655-667
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• 2019

This research aims to identify the possibility of developing A horizon resources that can be used for construction and civil engineering work. As such, the utility of A horizon resources was examined by establishing planting ground through a mixture of soil layers and by analyzing the growth and development of Pinus densiflora. The physicochemical and physical properties of the soil were as follows: the A horizon was sandy clay loam, B horizon was sandy loam, and the mixture of two layers appeared as sandy loam, which was identical to the B horizon. The experimental groups did not show any significant difference in their physical properties of porosity and degree of water-stable aggregates. With regards to chemical properties, the A horizon as well as the mixture of A and B horizon showed acidity while the B horizon showed alkalinity. The figures of organic matter, total nitrogen, available phosphate, and replaceable potassium were greater as the A horizon content increased, whereas the figures of replaceable calcium, replaceable magnesium, and conductivity increased as the A horizon content decreased. As a result of the growth and development of Pinus densiflora in each planting ground, the final survival rates were all above 100%. However, the tree height and the rate of growth for the diameter of root were higher in the order of A horizon > A horizon + B horizon > B horizon,indicating that the increased A horizon content is related to the growth and development of Pinus densiflora. The treatment of soil with improvement agents, used to recover the functions of in-situ soil showing poor growth and development, did not have a clear impact on the soil texture and porosity. However, the degree of water-stable aggregates increased significantly when using O horizon as the soil improvement agent among the types of in-situ soil. In contrast, all items related to the chemical properties showed significant differences following the treatment by soil improvement agents. The survival rate according to the treatment of soil improvement agents for the growth and development of Pinus densiflora was higher in the order of organic horizon = no treatment > compound fertilizer > organic fertilizer + compound fertilizer > organic fertilizer; this result was statistically significant with a marginal significance value of the log-rank test(p < 0.05).

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.101-107
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• 2020

Road surface measurement is an essential process for quantifying the degree and displacement of roughness in road surface management. For safer road surface management and quick maintenance, it is important to accurately measure the road surface while mounted on a vehicle. In this paper, we propose a sophisticated road surface measurement system that can be measured on a moving vehicle. The proposed road surface measurement system supports more accurate measurement of the road surface by using a high-performance line laser sensor. It is also possible to measure the transverse and longitudinal profile by matching the position information acquired from the RTK, and the velocity adaptive update algorithm allows a manager to monitor in a real-time manner. In order to evaluate the proposed system, the Gocator laser sensor, MRP module, and NVIDIA Xavier processor were mounted on a test mobile and tested on the road surface. Our evaluation results demonstrate that our system measures accurate profile base on the MSE. Our proposed system can be used not only for evaluating the condition of roads but also for evaluating the impact of adjacent excavation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.372-378
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• 2021

A body armor vest is a form of munition related directly to the safety and life of combatants. Therefore, it must meet the requirements for ballistic resistance. The ROK demands the performance of body armor vest meet the Level IIIA specified by the NIJ STD-0101.06 published by the US National Institute of Justice. This study performed acceptance tests on body armor vests. The factors for evaluating the ballistic resistance evaluated were not only whether it penetrates when shooting but also whether the BFS (Backface Signature) depth does not exceed 44 mm when it does not penetrate. The factors were assessed to determine if they were consistent or not. The BFS depth is affected by various test factors, such as the physical properties of the backing material and the changes in the amount of impact with the bullet velocity. In this study, an analysis of the bulletproof performance was performed by extracting the data with the same conditions using ANOVA to remove the influence of these external factors. The analysis revealed a correlation between the BFS depth, bullet velocity, vest conditions, and protection area. The mass production process was analyzed by estimating the Interval of BFS on each lot. Through this, a new methodology for ballistic resistance evaluation and paradigm for future quality assurance is suggested.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.6
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• pp.367-375
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• 2020

Background: Intraosseous anesthesia (IO) allows the anesthetic solution to be injected directly into the cancellous bone. The anesthetic solution immediately reaches the periapical region, and thus the axonal area of the nerve, where it can temporarily disable the sodium pump. The effect is felt almost without any time delay, and only a small amount of anesthetic solution is required. Methods: This study aims to investigate the efficacy of IO using the AnestoⓇ device after infiltration anesthesia (IA) and/or inferior alveolar nerve block anesthesia (IANB) failed to work in symptomatic irreversible pulpitis (hot tooth). The 33 patients included in the study were treated additionally with 1.7 ml articaine hydrochloride with 1:100,000 epinephrine hydrochloride (UltracainⓇ D-S, Sanofi-Aventis, Frankfurt, Germany) IO. Results: The electrical pulp test showed that 95.76% of the volunteers reacted positively to the combination of IANB or IA with the IO. In women, the additive IO was effective at 97.22%. In men, the IO led to pain elimination in 94.00% of cases. The duration of the IO was less than a quarter of an hour (13.03 min). The IO worked longer in women than in men (13.61 min vs. 12.33 min). Overall, more than every third tooth that needed trepanation was located in the posterior area of the mandible (36.4%). Treatment of hot teeth in this area was associated with an increased pulse rate and increased residual pain. There was a moderate correlation (Spearman-Rho [IRI] = 0.280) between the Visual Analog Scale (VAS) score and bone density, and a significant correlation (IRI = 0.612) between subjective residual pain and bone width. The IO resulted in a moderate, transient increase in the pulse rate by approximately 20 bpm. This is similar to the temporary increase in heart rate after conventional anesthesia techniques in non-preloaded patients and can be considered clinically irrelevant. Conclusion: IO with the AnestoⓇ device as an extension and deepening of local pain elimination is recommended for the treatment of hot teeth.

• The Korean Journal of Franchise Management
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• v.10 no.4
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• pp.19-29
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• 2019

Purpose: In beauty industry, service quality is very critical, because it impacts on the customer's positive attitude and behavior to the beauty salon or beauty brand. Thus, this research examines the effects of service attributes on customer satisfaction and loyalty in beauty salon. This research suggests the guidelines for how beauty salons should manage their physical environment, price policy, professional skills, and employees that improve management and business performance. Research design, data, and methodology: This study examines the structural relationship between service attributes, customer satisfaction, and loyalty. Service attributes divide into four sub-dimensions such as servicescape, price service, technical service, and employee service. In order to test the purposes of this research, research model and hypotheses were developed. All constructs were measured with multiple items developed and examined in previous studies. A total of 160 questionnaires were distributed and collected, and 150 were used for analysis except 10 that were unresponsive or unfaithful. The data were analyzed using SPSS 22.0 and SmartPLS 3.0 statistical package program. Result: The results of this research are as follows. First, all sub-dimensions of service attributes such as servicescape, price service, technical service, and employee service have significant positive impacts on satisfaction. Second, customer satisfaction have significant impact on loyalty. Conclusions: This study suggests an integrated model of the relationship that the characteristics of beauty salon service attributes affect customer loyalty through satisfaction, and suggests how to manage and allocate limited resources in the beauty industry. The findings of this research indicate that the level of customer satisfaction is shown to be increased by servicescape, technical characteristics, value of money, and human attributes. Thus, beauty salon management should focus on the relationship with their customers how to improve customer loyalty through satisfaction. The quality of beauty service influences customer's attitudes and behaviors toward beauty salon. Considering the beauty business, where the quality and customer satisfaction of beauty services are determined by the hairdresser's beauty skills,, the beauty salons must find ways to improve their skills and new trend of hair style. If beauty salon customers perceive the high quality of beauty service, they revisit beauty salon and recommend it to others.

• Journal of agricultural medicine and community health
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• v.45 no.4
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• pp.221-234
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• 2020

Objectives: The purpose of this study is to identify the policy compliance according to the socio-demographic characteristics, stress, satisfaction of relationship, Health Belief Model and characteristics of smoking behaviors and knowledge related smoking of the residents living in the Smoke-free apartment and to investigate the change of the smoking related behavior before and after the implementation of the policy. Methods: The subjects of the survey were 293 residents aged 19 or older who reside in apartments six months after the designation of Smoke-free apartment located in Daejeon. All collected data were analyzed using T-test, ANOVA and Hierarchical multiple regression of SPSS for windows(ver 24.0) program. Results: The policy compliance was higher in women and those who lived for less than two years, and non-smokers were significantly higher. The policy compliance of the whole subjects was related to satisfaction with the surrounding relationship, perceived disability about smoking cessation, frequency of smoking and the amount of smoking. The policy compliance of the whole subjects was related to the satisfaction of the surrounding relationship, the perceived disability about smoking cessation, and the amount of smoking. In addition, after the implementation of the gold research station designation policy, it had a positive impact on smoker's smoking behavior and resulted in reducing the frequency of secondhand smoke among residents. Conclusions: In order to increase the compliance of the non-smoking policy It is necessary to continuously expand the indoor smoking cessation zone policy, develop policies and supplement the health belief model components.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.573-582
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• 2021

In this study, a series of processes for evaluating the effective protection against barriers that should be equipped in institutions that perform reliability tests on high-risk ammunition, such as high-explosive ammunition, were introduced. The impact that high-explosive bombs can have on personnel includes damage to the eardrum and lungs caused by explosion overpressure and penetrating wounds that can be received by fragments generated simultaneously with the explosion. Therefore, a high-explosive with COMP B explosives as its contents were set up, and an explosion protection theory investigation to calculate the degree of damage, numerical calculations and simulations were performed to verify the protection power. A numerical calculation revealed the maximum explosion overpressure on the protective wall when the high-explosive exploded and the penetration force of the fragment against a 50 mm-thick protective wall to be 77.74 kPa and 41.34 mm, respectively. In the simulation verification using AUTODYN, the maximum explosion overpressures affecting the firewall and personnel were 56.68 kPa and 18.175 kPa, respectively, and the penetration of fragments was 35.56 mm. This figure is lower than the human damage limit, and it was judged that the protective power of the barrier would be effective.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.848-854
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• 2011

The objective of this research was to experimentally test the effect of rice straw mats on the reduction of runoff, sediment and discharge under a laboratory scale with different rainfall intensity and slopes. We used the small runoff plots of $1m{\times}1m{\times}0.65m$ ($L{\times}W{\times}H$) in size were filled with loamy sand. Experimental treatments were bare (control), rice straw mats + PAM(SP), rice straw mats + PAM + sawdust(SPS) and rice straw mats + PAM + rice husks(SPR); slope of 10% or 20%; and rainfall intensity of 30 or 60 mm/hr. Runoff volume and coefficient from covered plots were significantly lower than those from control plots. Under the 30 mm/hr and 10% simulations, average runoff coefficient of covered plots decreased more than 92%. Under 60 mm/hr and 20% simulations, the ratios were between 39.8~58.1%. Under the condition of 30 mm/hr rainfall and 10% slope, sediment discharge from covered plots was practically zero. And at 20% plots, sediment reduction ratio was more than 95%. Under the condition of 60 mm/hr rainfall, sediment reduction ratio of 10 and 20% plots ranged between 86.3~95.3% and between 79.8~86.5%, respectively. The differences in initial runoff time, runoff and sediment discharge among different cover materials were not significant. Rainfall intensity showed higher impact on initial runoff time, runoff, and sediment discharge than slope. It was also shown that even if runoff reduction by surface cover were low, sediment discharge reduction could be very significant and contribute to improve the water quality of streams in sloping agricultural regions. It was concluded that the use of straw mat and PAM on sloping agricultural fields could reduce soil erosion and muddy runoff significantly and help improve the water quality and aquatic ecosystem in receiving waters.

• Korean Journal of Labor Studies
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• v.23 no.2
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• pp.277-306
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• 2017

This article empirically explores the impact of minijobs in the wake of the Hartz reform in Germany on women's employment relationship. Theoretically it is of great significance to examine whether the minijobs play an active role as a bridge in leading the minijobbers to regular, socially secured jobs or not. Several interviews as well as secondary data I could get during my sabbatical in 2015 were used to test the theory. One of the main findings was the fact that the minijob labor market opened doors wide for women in Germany, particularly for career-interrupted women, students or pensioners. However, the minijob can easily become a trap of lowest income and poverty for women. Most women minjobbers cannot go over to regular, socially secured jobs. Especially in terms of collective industrial relations, it considerably damages the power of industrial unions and the legal binding force of collective agreement. In conclusion, this study makes it clear that the labor market segmentation theory rather than the transitional labor market theory is valid in accounting for the reality of minijob in Germany. In other words, the minijob in Germany has a Toijan Horse Effect. It also suggests, from a practical viewpoint, that German industrial unions or works councils organize the minijobbers and that the coverage of collective agreements be extended to the minijobbers. Consequently, the time-selective part-timer model put into practice in Korea in 2014 is not only invalid but also undesirable.