• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.74-79
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• 2022

In this study, the plasma corrosion resistance and the change in the number of contamination particles generated using the plasma etching process and cleaning process of coating parts for semiconductor plasma etching equipment were investigated. As the coating method, atmospheric plasma spray (APS) was used, and the powder materials were Y₂O₃ and Y₃Al₅O₁₂ (YAG). There was a clear difference in the densities of the coatings due to the difference in solubility due to the melting point of the powdered material. As a plasma environment, a mixed gas of CF₄, O₂, and Ar was used, and the etching process was performed at 200 W for 60 min. After the plasma etching process, a fluorinated film was formed on the surface, and it was confirmed that the plasma resistance was lowered and contaminant particles were generated. We performed a surface cleaning process using piranha solution(H₂SO₄(3):H₂O₂(1)) to remove the defect-causing surface fluorinated film. APS-Y₂O₃ and APS-YAG coatings commonly increased the number of defects (pores, cracks) on the coating surface by plasma etching and cleaning processes. As a result, it was confirmed that the generation of contamination particles increased and the breakdown voltage decreased. In particular, in the case of APS-YAG under the same cleaning process conditions, some of the fluorinated film remained and surface defects increased, which accelerated the increase in the number of contamination particles after cleaning. These results suggest that contaminating particles and the breakdown voltage that causes defects in semiconductor devices can be controlled through the optimization of the APS coating process and cleaning process.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.545-557
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• 2017

Objective: The aim of this study was to find risk factors in cultivating ginseng based on risk assessments and suggest safety measures for main risks. Background: Safety education and training is one of the practical and effective methods to prevent occupational accidents and injuries. In agricultural sector, there are few contents of safety education as compared to other industries. Especially, farm work has different cultivation characteristics according to the crops, so it needs special education materials for each crop. Among the various types of crops, ginseng contains various risk factors due to its long cultivating period and unique environment. Therefore, safety education material specified for ginseng is necessary to improve ginseng farmers' safety. Method: Risk assessment for cultivating tasks of ginseng was carried out through data obtained from various methods (site survey, interview, literature survey). To improve objectivity, the risk assessment was applied with 3-criteria (researcher estimate, interview, previous research results). Finally, the three high-risk tasks were selected and safety measures for those tasks were provided. Results: Three tasks, such as 'Mounting, maintenance and removing supports', 'Pest control' and 'Harvest', were selected as risky tasks among total tasks. (1) In 'Mounting' and maintenance and removing supports', the farmers found to be exposed to the risks of musculoskeletal disorders and accidents related to operating the tablet machine. (2) In 'Pest control', agrichemical poisoning, musculoskeletal disorders and hyperthermia were main risks. Finally, (3) In 'Harvest', the farmers are mainly exposed to the possibility of accidents of agricultural machines and risks of musculoskeletal disorders. Thus, it needs to apply appropriate safety measures to those risky tasks, such as safety guidelines, convenience equipment, protective kit, and so on. Conclusion: This study can be used as basic data for agricultural safety and expected that it would be useful for further study. In addition, the results of the research will be produced in the form of animation, which will enhance the safety consciousness for aged farmers. Application: The result of this study can be used in developing safety education materials for ginseng farmers which is essential to prevent occupational accidents and injuries among ginseng farmers.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.192-199
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• 2015

Under the economic banner of "self-reliance," North Korea has focused on hydro and thermal power as its main energy supply sources. However, in the face of extreme energy penury caused by machinery and material supply instability in the wake of the collapse of the former communist block as well as equipment aging and deterioration due to floods and other disasters, North Korea and international aid organizations are increasingly turning their attention toward energy source diversification. In particular, renewable energy is recognized as the best strategic energy source for North Korea and it is a decentralized energy option that is suitable in light of North Korea's power distribution networks and its pursuit of self-reliance. Biogas can contribute to improving the human rights situation of North Koreans in conjunction with an increase in food production. For this reason, renewable energy is the most promising option for an energy source that is likely to secure humanitarian aid from international organizations such as the Food and Agricultural Organization (FAO) and the World Food Programme (WFP). However, the implementation of such humanitarian aid has been hampered by rising concerns about the diversion of provided energy materials for military purposes and the disguised introduction of dual use items strategic materials as well as UN Security Council resolutions and sanctions of the international community against North Korea's military provocation, including nuclear tests and missile launches. This paper explores the possibility of solving this dilemma and proceeding with the humanitarian aid to North Korea by evaluating the potential for sanction and the risk of diversion of the possible products for biogas-related aid on the basis of the list of UN-sanctioned items.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.1
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• pp.45-53
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• 2014

PURPOSE: In this study, we tried to find out what kind of exercise was more effective in sleep disorder by comparing melatonin in blood after applying low intensity with high intensity exercise to sleep disordered rats induced by experiment. METHODS: We used male Sprague-Dawley rats which were 8weeks old and weighted 300g. They were supplied with water and food without any restriction. We kept the room temperature at $25^{\circ}C$ and controld the length of day and night in 12 hours blocks, respectively. We divided the rats 60 into 2 groups. To one group we applied low intensity exercise, and to the other we applied high intensity exercise for 15minutes per day over a period of 4 weeks. We extracted the blood from abdominal aorta before, after exercise, moved into EDTA tube, performed centrifugation. We decanted the serum $200{\mu}l$ from the blood into microcentrifuge tube by samples and moved into polypropylene culture tubes with micro pipette. We split enzyme solution $50{\mu}l$ into the tubes with melatonin direct kits and make them react at $37^{\circ}C$ for 2 hours. We split assay buffer $50{\mu}l$ into each tube and mixed melatonin tracer $50{\mu}l$ and melatonin antiserum $50{\mu}l$, respectively. After we made them react in room temperature, we decanted the superficial layer with a centrifuge and measured the activity for 1 minute by competitive method with ${\gamma}$-counter equipment. We draw a standard curve through logit-log graph with CPM(counts per minute) and counted the melatonin by B/B0. We conducted independent t-test to examine the homogeneous of melatonin value of before low-intensity and high-intensity exercise. We performed paired t-test to compare before and after low-intensity and high-intensity exercise, respectively. We carried out independent t-test to compare melatonin value after low-intensity and high-intensity exercise. Significance level was .05. RESULTS: The results were as follows; firstly melatonin was more increased in the group who was exposed to high intensity exercise when we compared before to after high and low intensity exercise, respectively. Secondly, high intensity exercise was more effective than low intensity exercise when we compared the two. CONCLUSION: In conclusion, secretion of melatonin which is the material of sleep improvement could be promoted by high intensity exercise. Low intensity exercise acted as a stress rather than improving sleep and had a negative effect on the secretion of melatonin because the melatonin was affected by stress.

• The Journal of Korean Medicine
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• v.28 no.3 s.71
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• pp.1-12
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• 2007

Objectives : The purpose of this study was to explore the perceptions of health promotion programmes using traditional Korean medicine among public health centre staff in charge of running such programmes. To do so, we examined and analysed the current situation of implementing the programmes in the public health centre. Methods : A survey was designed to collect information on perception of the health promotion programmes using traditional Korean medicine by public health centre staff in charge of running such programmes. The survey, using a structured questionnaire designed for this study, was conducted on 161 public health centre staff attending an annual meeting to presenting the results of activity evaluation related to public health programmes using traditional Korean medicine in public health centres. The participants were asked about the most successful programme, the benefits of the programmes, the positive aspects of the programmes, the most desirable outcomes of the programmes and so on. The data were analysed using SPSS system 12.0 for Windows. Results : Of the 161 questionnaires, 121 were analysed. The main findings of this research were as follows. Of the health promotion programmes using traditional Korean medicine implemented in public health centres, qigong and stroke preventive health promotion programmes were perceived as the most successful. The major benefits of the programmes were having merit for health promotion and expecting a positive performance outcome. The major positive aspects of the programmes for health promotion were cultivating community citizen's support and showing consistency between the philosophy of the programmes and the direction of existing health promotion programmes. The most desirable outcomes of the programmes were spreading community understanding of the programme and establishing an effective and unique health promotion model for implementing the programme. Two major causes of implementation difficulties were lack of material resources such as manpower, facility, and equipment, and methods of performance evaluation. One of the most urgent needs for activating the implementation of programmes was continuing financial and technical support from the central government. Conclusions : To promote the role of traditional Korean medicine in the public health sector in order to integrate traditional medicine into the public health system, government should develop some measures for solving the identified causes of implementation difficulties and coping with the most urgent needs for activating the implementation of programmes.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.6
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• pp.276-281
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• 2021

In order to manufacture a semiconductor circuit, etching, cleaning, and deposition processes are repeated. During these processes, the inside of the processing chamber is exposed to corrosive plasma. Therefore, the coating of the inner wall of the semiconductor equipment with a plasma-resistant material has been attempted to minimize the etching of the coating and particle contaminant generation. In this study, we synthesized yttrium oxyfluoride (YOF) powder by a solid-state reaction using Y₂O₃ and YF₃ as raw materials. Mixing ratio of the Y₂O₃ and YF₃ was varied from 1.0:1.0 to 1.0:1.6. Effects of the mixing ratio on crystal structure and microstructure of the synthesized YOF powder were investigated using XRD and FE-SEM. The synthesized YOF powder was successfully applied to plasma spray coating process on Al substrate.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.1
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• pp.18-25
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• 2024

Objectives: The primary aim of this study is to create an Occupational Safety and Health (OSH) guide for high-risk maintenance tasks, specifically one designed for maintenance work (MW) in the electronics industry. Methods: The methodology involved a literature review, field investigations, and discussions. An initial draft of the OSH guide was created and then refined through consultations with experts possessing extensive experience in MW for electronic processes. Results: Specific MW tasks within electronics processing facilities identified as high-risk by the research were selected. A comprehensive OSH guide for these tasks was developed consisting of approximately 11 to 12 components and encompassing about 20-25 pages. Implementing safety and health measures before, during, and after MW is crucial for the protection of maintenance personnel. The guide is enriched with real-case scenarios of industrial accidents and occupational diseases to enhance maintenance workers' comprehension of the OSH principles. For a clearer understanding of and adherence to the safety protocols, the guide incorporates visual aids, including cartoons and photographs. Conclusions: This OSH guide is designed to ensure the protection of workers involved in maintenance activities in the electronics industry. It aligns with global standards set by the International Organization for Standardization (ISO) and Semiconductor Equipment and Material International (SEMI) to ensure a high level of safety and compliance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6C
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• pp.295-304
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• 2012

In this study, a resonant column testing system which is the largest in Korea has been developed to evaluate the dynamic deformation characteristics of coarse granular geomaterials, and the performance and the applicability of the testing system have been verified. The system has been developed as a typical Stokoe type device whose boundary conditions are fixed bottom and free top with additional mass, and can adopt a large specimen with 200 mm in diameter and 400 mm in height. The driving and measurement instruments are configured as high performance and precision systems, hence the automated testing system is appropriate to drive enough stress and to measure the behavior precisely for the test in practical manner. The dynamic response of the mechanical components and the applicability of the system have been evaluated using metal specimens as well as polyurethane specimens, and its precision was verified by comparing its results with those from other equipment and/or methods. To confirm the applicability of the large system for coarse geomaterials, the resonant column test results from both large and normal scale apparatus for the same material were compared and it was found that the result can be partially affected by scale. Finally, the dynamic deformation characteristics of coarse geomaterial which is used for construction of large dam was evaluated using the large system and its practicality could be confirmed.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.401-412
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• 2020

This study analyzed the causes of warehouse fires using a creative problem-solving technique called TRIZ. It identified preventive measures by applying 4M. The results are as follows. First, this study examined the inconsistency among the causes of warehouse fires using TRIZ. Second, it analyzed human factors and fire prevention measures in warehouses such as safety standards for managers, and methods for the promotion of safety consciousness among workers, and for the reinforcement of construction technology for sandwich panel workers. Third, it identified the mechanical and facility factors and fire prevention measures in warehouses such as safety facilities, the expanded installation of safety devices, the adoption and development of fire suppression equipment, and the deployment of methods to improve the fire resistance of sandwich panels. Fourth, it presented working and environmental factors and fire prevention measures in warehouses such as the tightening of safety precautions and the supervision of working methods, and setting fire partitions both in loading places and based on performance-based design. Finally, it proposed managerial factors and fire prevention measures in warehouses such as specific targeting for firefighting with low fire hazards, reviewing the material quality regulations of non-combustible or higher for sandwich panels in the specific target of firefighting that cannot apply fire safety standards, installing sprinklers in cold storage, and mandating the installation of automated facilities with retroactive application regardless of the floor area in the warehouse with a sandwich panel structure.

• Korean Security Journal
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• no.11
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• pp.61-86
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• 2006

Various terrorism in modern society against nation's dignitaries are constantly existing. They damage severely to the society and the nation's security, and they cause disorganizations of social and national rule orders. In order to provide the key figures' perfect protection, the threatening terroizing environment for primary leaders and the route of terrorism should be intercepted. Effective methods of these are summarized as follow. First, recent terrorism against the primary leaders are mostly assassinations, bomb attacks, and suicide bomb attacks, which terminate in a moment. Therefore, security service agents should keep in mind that protection is the best, and government's anti-terrorism agencies should develop policies and set the directions within a new paradigm to the advance anti-terrorism. Second, advance prevention activities against nation's VIP terrorism should be strengthened, such as strengthening security informational activities, constructing cooperative systems of domestic and international facilities, considering continuous system to prevent terrorism, and intensifying safety counterplans of human and material weak points. Third, international cooperative system should be set to apply economical and political sanctions to nations which support terror organizations in direct or indirect ways, and this system needs to strengthen the punishment against terrorists. Fourth, security systems to protect nation's primary leaders should complement, and developing programs for coping with the terrorism and establishing laws for anti-terrorism should be made. Also, educational training of agents who perform anti-terrorism duties should be strengthened, and scientific techniques and equipment for security should be made to protect primary leaders from terrorism.