• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.493-498
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• 2008

Particles or deposit formed by corrosion of the pipe material bring about bad influences on the heating systems with inconvenience, energy loss and so on. In order to obtain the non-corrosive environments, the circulation hot water should properly be treated in several ways to satisfy one or more conditions of the followings: suitable pH-level, low hardness, low oxygen content, low conductivity, low level of chlorides and sulphur compounds and low level of solid particles. This experimental study was carried out to develope the new guidelines on the optimal water quality and directions for water quality management in heating systems. As results, it was recommended that the heating water be maintained pH-level not less than 8, hardness contents as $CaCO_3$ no more than 50 mg/L, turbidity no more than 10 NTU and T-Fe contents 1 mg/L below.

• 한국환경복원기술학회지
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• 제5권5호
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• pp.45-57
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• 2002

This study aims to suggest the applied zoning system for preventing reckless developments due to individual industrial facility construction. According to the types of reckless developments which has been found in Hwasung, the applied zoning system including 4 kinds of districts can be proposed. Collective Inducement District can be designated to where many industrial facilities have already existed with poor infrastructure, and the other districts such as Residential Area Protection District, Reservoir-Around and Agricultural Area Protection District, or Landscape Protection District may be designated to the sites where reckless developments due to individual industrial facility construction may happen. This zoning system seems to be used as a guideline of new zoning of revised NLUPL(National Land Use and Plan Law) after the execution.

• 한국환경복원기술학회지
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• 제13권5호
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• pp.28-37
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• 2010

This study is intend to evaluate natural conservation value, and to suggest natural park plan based on conservation value evaluation. In this study evaluation items are selected through related studies about ecological conservation evaluation, and evaluation items in this study can be classified into 2 aspects, ecological environment and topographic environment. After each evaluation items are overlaid with GIS program, management levels are derived from comprehensive overlaid maps of each evaluation items. Management areas can be classified into 5 levels; Critical Conservation Area, Conservation Area, Restoration Area, Passive Usable Area, Active Development Area and Settlement Area. So management areas can be matched each management levels to land use of natural park, that is district of preservation, district of natural environment, district of settlements and district of mass facilities. This study have good enough to evaluate ecological value for natural park plan, but, it is difficult to evaluate conservation value only with maps of each evaluation items, so it needs supplementary field survey for precise conservation value evaluation.

• 자원환경지질
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• 제25권4호
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• pp.379-395
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• 1992

The gold ore deposits of Nakcheon, Gongyeong and Dongmyeong mine in the Imgye district are E-W trending fissure filling veins emplaced in Precambrian Jungbongsan granite and sedimentary rocks of Cambrian Yangdeog group. The K-Ar age for vein alteration sericite and vein laced muscovite are 73 and 93 Ma, respectively. Vein structure and mineralogy indicate the three distinct depositional stages: I) basemetal sulfides and tin minerals, II) gold-basemeatl sulfides, III) gold-silver-basemetal sulfides. Major gold and silver ore minerals are electrum, native silver, pyrargyrite and argentite. Fluid inclusion data indicate that filling temperatures were from $350^{\circ}C$ to $190^{\circ}C$ through stage I, II and III. Salinities were in the range of 0.0~9.5 NaCl eq.wt.% and do not reveal any systematic trend. Intermittent boiling of ore fluid during stage I is indicated by fluid inclusions in quartz. Fluid pressure during stage I which is estimated from fluid inclusions showing boiling evidence range from 50 to 100 bars. Gold ore deposits of the Imgye district were formed under higher temperatures and lower sulfur fugacities compared with the Eunchi silver ore deposits about 8 Km apart from the Imgye district.

• 보건의료산업학회지
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• 제14권2호
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• pp.79-91
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• 2020

Objectives: The purpose of this study was to identify a regional difference among drinking behaviors, sober motivation, and drinking problems. Methods: The subjects included 600 citizens living in two regions, Busan. Descriptive analysis, t-test, correlation, and path analysis were used to confirm the regional difference. Results: The path of drinking method on sober motivation was statistically significant in both regions and drinking attitude was found to be a common factor that weakens an individual's sober motivation. Besides, the path of social networking on sober motivation had a difference in statistical significance between the two regions. Finally, the influence of social networks of District N (comparison region) on sober motivation was statistically significant and stronger than that of District D. Conclusions: A social environment-centered intervention to address drinking problems is essential in District N because of its people's tendency to drink together. On the other hand, an individual-focused intervention is preferred in District D where sober motivation is mainly affected by drinking method and attitude.

• 설비공학논문집
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• 제18권10호
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• pp.776-782
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• 2006

A new district cooling system using ice slurry for the uncertain cooling load of the future is presented. The chilled water produced by the absorption chillers is used for the base cooling load. The temperature of the chilled water is reduced by mixing of ice slurry depending on increasing of the cooling load. Finally, IF of the ice slurry is increased up to 10% at the peak load. The transporting mass flow rate is decreased down to 44.7%, and the diameter of the main pipe is decreased down to 66.7%, but the diameter of the branched pipe is designed as the same size of the chilled water.

• Corrosion Science and Technology
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• 제21권1호
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• pp.62-67
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• 2022

The objective of this study was to perform failure analysis of an inlet pipe located in a governor valve of a steam turbine in a district heating system. During the operation, the temperature of the governor valve was increased to as high as ~500 ℃, which induced thermal expansion of the inlet pipe along both axial and radial directions. While the inlet pipe did not have contact with the valve seat, the side plane of the upside was constrained by the casing part, which led the inlet pipe to experience stress field in the form of fatigue and creep. The primary crack was initiated at about 30 mm below the top where the complex stress field was anticipated. These results suggest that the main failure mechanism is a combination of thermal fatigue and creep during the operation supported by the observation of apparent beach marks on the fracture surface and pores near the cracks, respectively.

• Corrosion Science and Technology
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• 제21권4호
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• pp.243-249
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• 2022

The objective of the present study was to perform failure analysis of double-layered bellow (expansion joint), a core part of stress reliever, used to relieve axial stresses induced by thermal expansion of heat-transport pipes in a district heating system. The bellow underwent tensile or compressive stresses due to its structure in terms of position. A leaked position sufferred a fatigue with a tensile component for decades. A cracked bellow contained a higher fraction of martensitic phase because of manufacturing and usage histories, which induced more brittleness on the component. Inclusions in the inner layer of the bellow acted as a site of stress concentration, from which cracks initiated and then propagated along the hoop direction from the inner surface of the inner layer under fatigue loading conditions. As the crack reached critical thickness, the crack propagated to the outer surface at a higher rate, resulting in leakage of the stress reliever.

• The Journal of Asian Finance, Economics and Business
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• 제8권6호
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• pp.447-453
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• 2021

Human resources play a key role in developing and enhancing the manner in which an organization change. In fact, the role of human resource-related quality management has contributed greatly to the growth of the organization in both the short and long term. The purpose of the current study is to identify factors that influence human resource retention in Hanoi in the backdrop of growing economic performance of Hanoi in Vietnam's economy. Primary data was collected through questionnaires of 280 respondents from the four districts in Hanoi, including 25.2% of respondents working in Cau Giay district, 21.2% in Dong Da district, 34.2% in Ha Dong district, and 19.4% in Thanh Xuan district. After applying Cronbach's Alpha and Explore Factor Analysis (EFA) analysis, Durbin-Watson test, empirical results demonstrate that relationship among co-workers has a significant and positive contribution on the maintenance of human resources in the organization. Additionally, higher welfare facilities for an employee are more likely to impact the maintenance of human resources in the organization. Factors such as working environment, job placement, and leadership relationship have no adverse effect on the maintenance of human resources, although a positive impact could be established in all cases.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2023년도 제67차 동계학술대회논문집 31권1호
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• pp.437-438
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• 2023

This paper takes the Pingjiang historical and cultural district of Suzhou city as an example, collects 1439 visitor review data from Ctrip.com with the help of Python technology, and uses web text analysis to conduct research on high-frequency words, semantic networks and emotional tendencies to comprehensively assess the tourist perception of the Grand Canal heritage. The study found that: natural and humanistic landscape, historical and cultural accumulation, and the style of Jiangnan Canal are fully reflected in the tourists' perception of Pingjiang historical and cultural district; tourists hold strong positive emotion towards Pingjiang Road, however, there is still more room for renovation and improvement of the historical and cultural district. Finally, countermeasure suggestions for improving the tourist perception of the Grand Canal heritage are given in terms of protection first, cultural integration and innovative utilization.