• Proceedings of the KWS Conference
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• 2010.05a
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• pp.23-23
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• 2010

마찰교반접합(Friction Stir Welding)은 1991년 영국 TWI에서 개발된 접합 법으로서 일정한 속도로 회전하는 툴이 재료내부에 삽입 되면서 툴과 재료사이에서 마찰열이 발생하여 연화된 재료와 접합 툴 사이에서의 기계적 교반에 의해 소성변형이 일어남과 동시에 접합이 이루어진다. 마찰교반접합은 동적 재결정에 의한 접합부의 미세한 결정립 형성으로 인하여 기계적 특성이 향상되며 보호 가스가 필요 없어 친환경적임과 동시에 용융 용접 법에 비해 접합 시 에너지 소모가 적다는 장점이 있다. 마찰교반접합은 기존의 저융점 재료에 관한 접합을 넘어서 최근에는 철계 합금, 타이타늄 합금, 니켈계 합금 등 고융점 재료에서의 적용에 관한 연구가 이루어지고 있다. 하지만 마찰교반접합을 이용하여 위와 같은 강한 재료를 접합하기 위해서는 내구성이 갖추어진 툴이 반드시 수반된다. 슈퍼 오스테나이트계 스테인리스강은 염화물의 농도가 높은 부식 환경에 적용되는 소재로서, 공식(pitting corrosion) 및 틈부식 (crevice corrosion)에 대한 내식성을 높이기 위하여 Mo의 함량을 6%로 낮추고 20~25% Cr과 Ni을 첨가하여 사용된다. 이러한 고합금의 슈퍼 오스테나이트계 스테인리스강은 여타 내식성 합금에 비하여 내식성이 매우 우수한 것으로 알려져 있다. 최근 SO2 배출에 대하여 규제가 강화되면서 화력 발전소용 탈황 설비 중 일부 장비에서 6% Mo가 첨가된 슈퍼 오스테나이트계 스테인리스강의 사용이 늘어나고 있다. 본 연구에서는 $Si_3N_4$ 툴을 사용하여 Mo이 6% 첨가된 슈퍼 오스테나이트계 스테인리스강인 1925hMo강을 마찰교반접합하였다. 툴 회전속도 (200rpm, 300rpm, 460rpm, 700rpm)를 변수로 하여 접합을 실시하였다. 접합 후 외관상태를 점검하였으며 광학현미경 (optical microscope)과 주사전자현미경 (scanning electron microscope)을 사용하여 미세조직 관찰을 하였으며 경도 및 인장강도 측정 등의 실험을 통하여 접합부의 기계적 특성을 평가하였다. 그 후 이러한 결과를 통하여 미세조직과 기계적 특성과의 관련성을 조사하였다.

• Journal of the Korean Institute of Landscape Architecture
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• v.41 no.4
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• pp.10-16
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• 2013

Korean housing developers are in a very competitive market and their way of attracting buyers is landscaping better than competing firms do. Thus, transplanting larger pine trees(Pinus densiflora S. et. Z.) is in vogue. A typical case is a pine tree about 30-year old, 35 diameters at breast height, transplanted 223 km afar from the Gangwon Province to Seoul. We estimated and compared carbon emissions during the whole transplanting works, and carbon intake by the tree if it survives 50 more years on site. Findings are; first, a large tree will take up and sequestrate approximately 90 kgC if it survives 50 more years. Second, transplanting works emit approximately 113.69 kgC, which is about 1.26 times of its possible future intake of carbon. Landscaping is a legal requirement for the purposes not only of aesthetics but also of environmental quality. Transplanting larger trees that came from a dam or a road building site may be inevitable and acceptable. However, transplanting larger trees long distance was evaluated to be harmful to the environment. It is strongly recommended to prohibit transplanting large trees. Landscape professionals need to guide clients to have desirable consumer attitude.

• Journal of dental hygiene science
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• v.9 no.1
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• pp.35-41
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• 2009

In previously study, many researchers have showed the infection control level and the knowledge of dental hygienists about dental infection control. But, they not tried to research the reason why hygienists don't keep to the infection control regulation closely. Therefore, this study was intended to highlight the affect factor that the infection control regulation keep in all dental hospitals well. The respondents in this research were the dental hygienists who worked in Incheon or Gyeonggi areas between June 16 and July 5, 2008 and who attended a complementary training program conducted by the Seoul Branch of Korean Dental Hygienists Association in April 2008. A total of 191 questionnaires were distributed to them, and the collected data was analyzed using SPSS WIN 12.0. Cross-tabulation analysis($X^2$), which significance level was 0.05, was applied to the data in order to verify the statistical significance of the survey method. According to replied, the reason why they don't used gloves were an unconvinced (38.9%), don't use by dentist (29.6%) and much expensive (9.3%). The gloves supplied a hygienist were proper in most case, 94.8%, but short in hospital, 12.0%. In order to take a good infection control they needed to change the conscious of dentist (66.5%), and the will of dentist is most important to do good infection control (37.2%). Subsequently, the will of dentist is the most important factor in infection control area and must be changed their mind on the infection control.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.55-64
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• 2013

The complexity of constructing medical institutions is higher than that of general buildings, and many change orders in the design and defect repairs in the construction phase are required due to strict government regulations. The priority control of constructions and impact factors of medical institutions were analyzed in this study, and difficulties in the control in the design and construction phase were identified. First, the priority management factors that were identified were as follows: architecture, facilities, and electricity. Second, 1) priority management in constructions and factors resulting in change orders and 2) priority management in constructions involving defect repair were analyzed. Third, the importance recognized by the construction managers were analyzed. The priority management in constructions and factors that were recognized by the construction manager were deducted as having low importance, although there were many change orders and defects. The work of finishing, wall building, joining, office automation and communication function, and lighting were analyzed in the design phase, and waste, the office automation and communication function, ceilings, contamination control, and plumbing were analyzed in the construction phase. The results showed that there will be a decrease in change orders and defects if the concentration of the manager was elevated and priorities were managed.

• Journal of Korea Port Economic Association
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• v.37 no.1
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• pp.143-157
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• 2021

International organizations such as the World Health Organization, the Organization for Economic Development and Cooperation, and major developed countries recognize the seriousness of air pollution. International organizations such as the International Maritime Organization have also implemented various regulations to reduce air pollution from ships. In line with this international trend, the government has also enacted a special law on improving air quality in port areas, and is making efforts to reduce air pollution caused by ports. The purpose of the Special Act is to implement comprehensive policies to improve air quality in port areas. This study sought to identify the emissions of each source of air pollutants originating from the port and prepare basic data on setting the policy priorities. To this end, the analysis was conducted in six categories: ships, vehicles, loading and unloading equipment, railways, unloading/wild ash dust, road ash dust, and the methodology presented by the European Environment Agency(EEA) and the United States Environmental Protection Agency(EPA). The pollutants subject to analysis were analyzed for carbon monoxide(CO), nitrogen oxides (NOX), sulfur oxides(SOX), total airborne materials(TSP), particulate matter(PM10, PM2.5), and ammonia(NH3). The analysis showed a total of 7,122 tons of emissions. By substance, NOX accounted for the largest portion of 5,084 tons, followed by CO (984 tons), SOX (530 tons), and TSP (335 tons). By source of emissions, ships accounted for the largest portion with 4,107 tons, followed by vehicles with 2,622 tons, showing high emissions. This proved to be the main cause of port air pollution, with 57.6% and 36.8% of total emissions, respectively, suggesting the need for countermeasures against these sources.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.180-188
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• 2020

To replace Japanese coal ash used in the domestic cement production and to recycle large quantities of domestic pond ash, it is essential to develop the technologies for quality control of cement by using the domestic pond ash. Thus, in this study, the feasibility of using the pond ash as a raw material for cement was investigated through chemical composition and microstructure analysis. As a result, most of the domestic pond ash contained slightly more Fe2O3, chloride, and unburned carbon contents than Japanese coal ash. In particular, the contents of chloride were considerably low in the pond ash that was transferred to fresh water or collected from surface of landfill area. However, since circulating fluidized bed boiler coal ash had relatively high SO3 contents causing durability problems of cement, it was not suitable for use as a raw material for cement. Thus, to replace Japanese coal ash with the domestic pond ash, it is necessary to introduce the adjustment of mixture proportion of cement raw materials and the process of removing chloride in the pond ash.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.787-796
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• 2010

The main reason of the earth global warming is $CO_2$ and the regulation about it in the whole world has been reinforced to reduce $CO_2$ emission. It is needed that we should reduce it in the process at the production of concrete generated much of $CO_2$ emission as the primary material of construction industry recognized unfriendly environment industry. Based on a concrete, this study was constructed the system to evaluate $CO_2$ emission generated in the stage of material production, transportation, manufacture and developed the program to reduce and evaluate it efficiently. As a result, most of $CO_2$ emission is generated in the stage of material and it is quantitatively evaluated $CO_2$ emission generated in the stage of materials, transportation and manufacture. Moreover, the evaluation system of the volume of $CO_2$ emission which has the friendly environment technology about reduction of $CO_2$ emission at each stage is suggested for quantitatively evaluation $CO_2$ emission generated in the process at the production of concrete and remicon production company could use it to evaluation $CO_2$ emission.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.231-240
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• 2018

Automobile industry is facing a variety of risks, including the rise of international oil price and the increase of car prices. In addition to the government's deregulation, efforts should be made to improve management aiming at higher production efficiency. In this study, we established a model for evaluating the procurement logistics based on the Fuzzy-AHP-TOPSIS by using the factors that are actually used in real companies aimed at the improvement of procurement logistics. A total of three automobile factories of Company G were chosen as the evaluation subject. In the result of the Fuzzy-AHP analysis that was conducted on a sample of three car factories, solving the long-term quality problems, minimizing the stop time due to the shortage of materials, preventing the of equipment accident, and solving the short-term quality problems were proven to be the most important factors. TOPSIS analysis result indicated that Factory B had the best procurement logistics. Our study has significance that it can contribute to the improvement of efficiency in the automobile industry as the evaluation model suggested in this study can be used for regular evaluation related to the procurement logistics in the future.

• Journal of Animal Environmental Science
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• v.11 no.3
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• pp.189-196
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• 2005

This study was carried out to determine the acceptability of liquid manure bin among livestock farmers and agricultural farmers, and quantify its malodorous compounds. The results were as follows; 1. The size of the manure bins owned by $93\%$ of 60 farmers surveyed was 200 M/T and were all in normal operation. Around $57\%$ of the normally operated bins were processed under aerobic condition. 2. Filly percent of the respondents utilized their liquid manure bin twice a year while $64\%$ used commercial microbial products to enhance maturity of their liquid manure and abatement of malodorous emissions. On the other hand, $43\%$ mentioned problems on the labor requirement, mechanical maintenance and lending cost of liquid manure processing and utilization, and the price of the commercial microbial products. 3. Malodorants emitted from livestock liquid manure bins and their boundary bin depended upon the livestock liquid manure processing condition. Within bin under the aerobic processing condition, Iso-valeric and propionic acid were ranged 0.012 to 0.07ppm and 0.17 to 2.85ppm, respectively. Within bin under the anoxic processing condition, n-butyric, n-valeric acid, and acetaldehyde were ranged 1.5 to 2.3ppm, 1.3 to 1.8ppm, and 0.8 to 2.1ppm, respectively. Malodorants emitted from the boundary of livestock liquid manure bins under the anoxic processing condition were detected the range of 0.4 to 0.9 ppm, more than the concentration of law regulation, as an acetaldehyde, but under the aerobic processing condition, they did not any detection.

• Journal of Korea Entertainment Industry Association
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• v.15 no.8
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• pp.19-31
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• 2021

This study tried to identify the characteristics of college students' entrepreneurial intentions in the entertainment industry, focusing on existing literature studies. Based on this, it was intended to suggest realistic educational alternatives for university student start-ups and implications for start-up management to university start-up officials and those in charge of national start-up support policy. Therefore, the implications of this study are as follows. First, technology(item) for idea creation education, which is an essential element in the entertainment industry, how to connect ideas and products, technology methods that can increase content value, and user characteristics education within the entertainment industry will need to be continued. In addition, along with the idea education, it is necessary to increase the understanding of start-up business management such as financing, human resource management, marketing, and operation management, and furthermore, confidence education should be provided so that the possibility of success in an entertainment start-up and a sense of adventure in a new job can be developed. Second, the space and equipment necessary for start-up (club room, student start-up room, entertainment-related equipment, etc.) should be provided centering on the opinion survey of students who are interested in starting a business, and various regulations of universities and government for student start-up should be relaxed. will have to In addition, education for the formation of entrepreneurial knowledge inside and outside of the school, special lectures and consultations by experts, and on-the-spot education, etc., should be made to create more practical entrepreneurial knowledge. something to do. Third, for students wishing to start a business in the entertainment industry, it is necessary to inform their families about the field situation of the entertainment industry accurately so that their children can develop a positive perception rather than a negative perception when choosing a business field. In addition, by promoting various successful cases of college students to their families after starting a business, families should be encouraged so that their children can develop a challenging spirit about starting a business. Fourth, it should be possible to form continuous clubs or gatherings with friends who wish to start a business in the entertainment industry, and furthermore, an opportunity to listen to the opinions of friends who actually started a business through these meetings should be provided. In addition, the meeting and the formation of friends should create a place for discussion about writing a business plan, how to succeed in starting a business, and management of startups, and psychological stimulation activities should be conducted so that each other's will to start a business arises. Fifth, various knowledge related to start-up (methods for securing funds, management of start-up organizations, grasping information about the market in which they want to start a business, etc.) should be cultivated, and how to write a business plan for the various entertainment industry fields they want to start up. You will also need to train them to be practical. Also, based on this knowledge formation, students themselves should be able to respond to risks and changes that may occur in entrepreneurship. Lastly, it is necessary to increase the understanding of business start-up management, and various psychological stimulation activities are needed to make the confidence and fear of starting a business disappear.