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Review for Mechanisms of Gas Generation and Properties of Gas Migration in SNF (Spent Nuclear Fuel) Repository Site (사용 후 핵연료 처분장 내 가스의 발생 기작 및 거동 특성 고찰)

  • Danu Kim;Soyoung Jeon;Seon-ok Kim;Sookyun Wang;Minhee Lee
    • Economic and Environmental Geology
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    • v.56 no.2
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    • pp.167-183
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    • 2023
  • Gases originated from the final SNF (spent nuclear fuel) disposal site are very mobile in the barrier and they may also affect the migration of radioactive nuclides generated from the SNF. Mechanisms of gas-nuclide migration in the multi-barrier and their influences on the safety of the disposal site should be understood before the construction of the final SNF disposal site. However, researches related to gas-nuclide coupled movement in the multi-barrier medium have been very little both at home and abroad. In this study, properties of gas generation and migration in the SNF disposal environment were reviewed through previous researches and their main mechanisms were summarized on the hydrogeological evolution stage of the SNF disposal site. Gas generation in the SNF disposal site was categorized into five origins such as the continuous nuclear fission of the SNS, the Cu-canister corrosion, the oxidation-reduction reaction, the microbial activity, and the inflow from the natural barriers. Migration scenarios of gas in porous medium of the multi-barrier in the SNF repository site were investigated through reviews for previous studies and several gas migration types including ① the free gas phase flow including visco-capillary two-phase flow, ② the advection and diffusion of dissolved gas in pore water, ③ dilatant two-phase flow, and ④ tensile fracture flow, were presented. Reviewed results in this study can support information to design the further research for the gas-nuclide migration in the repository site and to evaluate the safety of the Korean SNF disposal site in view points of gas migration in the multi-barrier.

Preparation of Novel Natural Polymer-based Magnetic Hydrogels Reinforced with Hyperbranched Polyglycerol (HPG) Responsible for Enhanced Mechanical Properties (과분지 폴리글리세롤(HPG) 강화를 통해 기계적 물성이 향상된 새로운 천연 고분자 기반 자성 하이드로젤의 제조)

  • Eun-Hye Jang;Jisu Jang;Sehyun Kwon;Jeon-Hyun Park;Yujeong Jeong;Sungwook Chung
    • Clean Technology
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    • v.29 no.1
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    • pp.10-21
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    • 2023
  • Hydrogels that are made of natural polymer-based double networks have excellent biocompatibility, low cytotoxicity, and high water content, assuring that the material has the properties required for a variety of biomedical applications. However, hydrogels also have limitations due to their relatively weak mechanical properties. In this study, hydrogels based on an alginate di-aldehyde (ADA) and gelatin (Gel) double network that is reinforced with additional hydrogen bonds formed between the hydroxyl (-OH) groups of the hyperbranched polymer (HPG) and the functional groups present inside of the hydrogels were successfully synthesized. The enhanced mechanical properties of these synthesized hydrogels were evaluated by varying the amount of HPG added during the hydrogel synthesis from 0 to 25%. In addition, magnetite nanoparticles (Fe3O4 NPs) were synthesized within the hydrogels and the structures and the magnetic properties of the hydrogels were also characterized. The hydrogels that contained 15% HPG and Fe3O4 NPs exhibited superparamagnetic behaviors with a saturation magnetization value of 3.8 emu g-1. These particular hydrogels also had strengthened mechanical properties with a maximum compressive stress of 1.1 MPa at a strain of 67.4%. Magnetic hydrogels made with natural polymer-based double networks provide improved mechanical properties and have a significant potential for drug delivery and biomaterial application.

Evaluation of Particle Size Effect on Dynamic Behavior of Soil-pile System (모래 지반의 입자크기가 지반-말뚝 시스템의 동적 거동에 미치는 영향 평가)

  • Han, Jin-Tae;Yoo, Min-Taek;Yang, Eui-Kyu;Kim, Myoung-Mo
    • Journal of the Korean Geotechnical Society
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    • v.26 no.7
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    • pp.49-58
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    • 2010
  • This paper presents experimental results of a series of 1-g shaking table model tests performed on end-bearing single piles and pile groups to investigate the effect of particle size on the dynamic behavior of soil-pile systems. Two soil-pile models were tested twice: first using Jumoonjin sand, and second using Australian Fine sand. In the case of single-pile models, the lateral displacement was almost within 1% of pile diameter which corresponds to the elastic range of the pile. The back-calculated p-y curves show that the subgrade reaction of the Jumoonjin-sand-model ground was larger than that of the Australian Fine-sand-model ground at the same displacement. This phenomenon means that the stress-strain behavior of Jumoonjin sand was initially stiffer than that of Australian Fine sand. This difference was also confirmed by resonant column tests and compression triaxial tests. And the single pile p-y backbone curves of the Australian fine sand were constructed and compared with those of the Jumoonjin sand. As a result, the stiffness of the p-y backbone curves of Jumunjin sand was larger than those of Australian fine sand. Therefore, using the same p-y curves regardless of particle size can lead to inaccurate results when evaluating dynamic behavior of soil-pile system. In the case of the group-pile models, the lateral displacement was much larger than the elastic range of pile movement at the same test conditions in the single-pile models. The back-calculated p-y curves in the case of group pile models were very similar in both sands because the stiffness difference between the Jumoonjin-sand-model ground and the Australian Fine-sand-model ground was not significantly large at a large strain level, where both sands showed non-linear behavior. According to a series of single pile and group pile test results, the evaluation group pile effect using the p-multiplier can lead to inaccurate results on dynamic behavior of soil-pile system.

A Study on the Narratives of Lee Ae-rim's Comic Books -Focusing on the Characteristics of Repetition, Coincidence, and Fantasy (이애림 만화 서사 연구 -반복, 우연, 환상의 특성을 중심으로)

  • Lee, Cheong
    • Journal of Popular Narrative
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    • v.25 no.1
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    • pp.281-313
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    • 2019
  • This paper was written to investigate the narrative traits of Lee Ae-rim's Comic Books. Lee Ae-rim arrived on the scene with the boom of comic book magazines in the 1990s. Although she started her career as a Comic Book writer, she expanded her own area gradually and has been working actively as an animation director as well. The superficial characteristics of Lee Ae-rim's works can be summed up as sexuality, grotesqueness, and fantasy. In other words, Lee Ae-rim's comic books are mainly characterized by the visualization of sexual, grotesque, and fantastic shapes. Lee Ae-rim has faced challenges with her own overwhelming and compelling images like no one else. For that reason, it is true that people haven't paid careful attention to the hidden stories behind her pictures. This paper considers that looking back on the narratives that Lee Ae-rim has been interested in, from early days to recent days, that is to say, the contexts of stories, is a shortcut to reveal a point of contact between her past, present, and future. Especially, this paper focused on the properties of the circulated and repeated stories, the stories ruled by fate and coincidence, and the stories in which elements of fantasy encounter an attempt of violation. As a result, it was found that the narratives of Lee Ae-rim's comic books demand us to face suppressed desires in a new way, by wrapping up the most fundamental aspects of human being in universality and constancy with specificity and grotesqueness. The reason why Lee Ae-rim has continued the avant-garde and omnidirectional works thus far explains what our society suppresses, inversely. Moreover, the narratives of Lee Ae-rim are significant, by being devoted to the right function of art not only to disclose suppressed desires but to satisfy them. Making an in-depth investigation of the narratives of Lee Ae-rim's comic books in various contexts, this research is intended to establish a diversity of Korean comic books, by adding meaning to the creative values of individual writers.

A Study on the Women's Voice in Oral Narratives of Social Memory of National Violence ('5.18') ('5.18'의 기억 서사와 '여성'의 목소리)

  • Kim, Young-hee
    • Issues in Feminism
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    • v.18 no.2
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    • pp.149-206
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    • 2018
  • This essay is focused on finding women's voice in oral narratives of social memory of national violence and resistance. The books of oral narratives of women who had experienced the national violence and participated in the resistance through historic events such as 5.18, have been published recently. This study is based on the materials that have interviewed women experienced the historic event '5.18' in Gwangju. In this study, there are analyses of the materials of the memory of violence and resistance of '5.18', which have contained the texts written by intellectual males and the oral narratives of females directly involved. So far, the memory and experience of women have not been presented in its entirety in the field of social discourse of '5.18'. In the field women's words were translated in men's words, so the real words disappeared and in the end remained unspoken words. And besides, the existence of women are substituted with the limited images (for example women's body destroyed) presented by men's words in memorial materials. In narratives of '5.18', women are reduced to the images of bodies destroyed by national violence. The destroyed bodies are places for exhibition and disclosure of national violence. Women are not presented as the subjects of the social resistance in oral or written narratives of '5.18'. The images of females are only vehicles to urge the male subjects to resist against unjust violence. In this context, men are interpreted for the protectors of sisters, daughters, wives. Since 1980s, the symbol of '5.18 Gwangju' has represented the most ideal community in Korean society. But women have been on the borderline or outside of the community in fact. However, women intend to construct themselves as the subjects of resistance through the spoken words. They have tried to make the politic places for themselves in the social field by speaking and speaking constantly. The desire to speak out is becoming stronger for women, so these days more words are spoken by more women and more oral narratives made by women are revealed in social discoursive field. So the place for women's voice is expanding in social memorial field of '5.18'.

A Study on the development of Creative Problem Solving Classes for University Students (창의적 문제해결형 대학 수업 개발 연구)

  • Hyun-Ju Kim;Jinyoung Lee
    • The Journal of the Convergence on Culture Technology
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    • v.9 no.6
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    • pp.531-538
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    • 2023
  • Recently, many university classes have been changing from instructor-centered classes to learner-centered classes, and universities are trying to establish a new direction for university education, especially to foster talented people suitable for the Fourth Industrial Revolution. To this end, universities are presenting various competencies necessary for students and focusing on research on efficient education plans for each competency. Among them, creativity is considered the most important competency that students should obtain in universities. Developing a creative problem-solving-based subject where various majors gather to produce results while conducting creative team activities away from desk classes is considered a meaningful subject to cultivate capacities suitable for the requirements of the times. Therefore, this study purpose to develop creative problem-solving-based subjects and analyze the results of class progress. This creative problem-solving-based class is an Action Learning class for step-by-step idea development, which starts with a theoretical lecture for creative idea development and then consists of five stages of Action Learning. The tasks of action learning used in this class consisted of ceramic expression to increase the intimacy of the formed group and the group's collective expression, ideas in life to combine and compress individual ideas into one, environmental improvement programs around schools, and finally UCC on various topics. In the theoretical lecture conducted throughout the class, a class was conducted on Scientific Thinking for creative problem solving, and then a group-type action learning class was conducted sequentially. This Action Learnin process gradually increased the difficulty level and led to in-depth learning by increasing the level of difficulty step by step.

Physiological and Psychological analysis of musculoskeletal symptoms (근골격계질환에 대한 물리적/심리적요인에 대한 연구)

  • Donghyun Park;Sung Kyu Bae
    • Korean Journal of Culture and Social Issue
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    • v.9 no.spc
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    • pp.107-122
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    • 2003
  • The object of this study is to evaluate the prevailing physical and psychosocial conditions regarding occupational low back injury. This study consists of two parts. In the first part of the study, analytic biomechanical model and NIOSH guidelines are applied to evaluate risk levels of low back injury for automobile assembly jobs. Total of 246 workers are analysed. There are 20 jobs having greater back compressive forces than 300kg at L5/S1. Also, there are 44 jobs over Action Limit with respect to 1981 NIOSH guidelines. The relationship between psychosocial factors and low back injury was examined in the second part of the study. A battery of questionnaires concerning the psychosocial stress based on PWI (Psychosocial Well-being Index) and musculoskeletal pain symptoms at low back was completed by 246 workers at the same plant. Results showed that 207 out 246 workers experienced the symptoms and 27 workers were diagnosed as patients. Two groups(low stressed, high stressed) based on PWI score had no significant relationships with both symptoms and results of diagnosis. The relationships between physical work load and psychosocial stress were also analysed. Specifically, some postural factors(vertical deviation angle of forearm, horizontal deviation angle of upperarm, vertical deviation angle of thigh, etc) were highly correlated with psychosocial stress. The results illustrated that PWI scores were associated with some physical workloads. However, psychosocial stress levels couldn't be well related with the pain symptom as well as the actual incidence of low back injury since pain or discomfort regarding low back injury were more complex than that of other musculoskeletal disorders.

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A Study on the Effects of Retirement Expectations & Social Supports & Entrepreneurial Intention for Employees Engaged in Financial Business on the Preparation for their Old Age (금융업 종사자의 은퇴기대, 사회적 지지 및 창업의지가 노후준비에 미치는 영향에 관한 연구)

  • Kim, Hyong-Sok;Kang, Shin-Kee
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.1
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    • pp.251-265
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    • 2022
  • According to the 2019 statistics of the National Statistical Office, the population of old people over 65 is 7.69 million which consists of 14.9% of total population in Korea, and the world's fastest compressed-aging is being processed. Employees engaged in financial business as representative high-wage workers tend to choose voluntary retirement regardless of their business types, and rarely get a new job or establish their own business successfully. This study analyzes the effects of retirement expectations, social supports, and entrepreneurial intention for employees engaged in financial business, and the differences by individual characteristics on the preparation for their old age. The subjects include 280 people working at Seoul metropolitan and Daegu area. The data were analyzed with the SPSS Win Ver. 18.0 for frequency analysis, reliability analysis, factor analysis, regression analysis, etc. and the results of the study are as follows. First, the result of analyzing the effect of retirement expectations of employees engaged in financial business on the preparation for old age shows that the retirement expectations of the people who consider retirement is a new start meaningfully affect the financial and physical preparations for old age. Second, it is shown that family relations for employees engaged in financial business meaningfully affect the financial preparation, and family relations and friendship relations meaningfully affect the emotional and social preparations, despite social supports do not relevantly affect the financial preparation for old age. Third, it is also shown that the entrepreneurial intention of employees engaged in financial business does not relevantly affect the financial and physical preparations, but meaningfully affects the emotional and social preparations for old age. Fourth, the result of analyzing the effect of the individual characteristics of employees engaged in financial business on the preparation for their old age shows that age, marital status, and job grade do not relevantly affect, but the experience of entrepreneurship education more affects the preparation for old age than no-experience.

A Study on the Properties and Mix Design of Eco-friendly Concrete Bricks Using Recycled Fine Aggregates (순환잔골재를 활용한 친환경 콘크리트 벽돌의 물성 및 배합설계 연구)

  • Choi, Hyungkook;Yang, Sungchul;Son, Jaeho;Lee, Seunghyun
    • Korean Journal of Construction Engineering and Management
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    • v.25 no.5
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    • pp.32-40
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    • 2024
  • In the construction industry, lack of reliability in the quality of recycled aggregates, harmful substance problems, and negative consumer perceptions limit the expansion of the use of recycled aggregates. In this respect, existing studies mainly focus on the use of recycled coarse aggregates in concrete in consideration of durability. On the other hand, in the case of recycled fine aggregates, not only are there insufficient cases applied to major structures, but the scope of application is very limited due to lack of awareness. Therefore, the main purpose of this study is to present the possibility of their application in bearing and non-bearing wall structures through physical characteristics experiments of concrete bricks for masonry according to various mixing ratios of recycled fine aggregates and cement amounts. To this end, the compressive strength and absorption rate of concrete bricks were measured focusing on the mixing ratio of the recycled fine aggregate and the crushed fine aggregate and the amount of cement. As a result, it is found that it is possible to use 100% of recycled fine aggregate for 200kg/m3 of cement or 25% of crushed fine aggregate mixed with 75% of recycled fine aggregate for the same amount of cement to achieve the compressive strength of 13MPa, witch is one of the quality requirements for concrete bricks for bearing walls. In addition, it is found that to meet the strength of 8MPa, one of the quality requirements for non-bearing walls, it is sufficient to use 100% of the recycled fine aggregate for 100kg/m3 of cement. Through the absorption rate tests, it is also confirmed that the absorption rate of the concrete brick is 13% or less by meeting the required performance criteria. This means that even if recycled fine aggregate is used in the manufacture of concrete bricks, the quality standards required by KS F 4004 (concrete bricks) can be sufficiently met.

An Empirical Study of Social Entrepreneurial Orientation as an Influence on Sustainability Performance of Social Enterprise: The Moderating Effect of Social Network Capabilities (사회적기업의 지속가능 경영성과에 영향을 미치는 사회적기업가 지향성에 관한 실증적 연구: 사회 네트워크 역량의 조절효과)

  • Chang Bong Kim;Tae Ho Yun
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.19 no.4
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    • pp.69-85
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    • 2024
  • Social enterprises, hybrid organizations that blend the logic of the public and market economies, have emerged as an alternative to market failure. However, due to the government-led compressed growth of social enterprises, many social enterprises rely on government financial support, and when the support ends, the survival rate drops significantly and the scale remains at the microenterprise level, raising concerns about the quality growth and sustainability of social enterprises. Therefore, the purpose of this study is to identify the social entrepreneurial orientation that affects the sustainable management performance and to empirically analyze the moderating effect of network utilization capabilities in this process. To achieve the purpose of this study, a questionnaire was distributed to a random sample of member organizations in the metropolitan area, including the Incheon City Small Business Association, the Gyeonggi-do Small Business Association etc. The survey was conducted for about two months and a total of 1,300 questionnaires were distributed and 180 were returned, of which 173 were used for empirical analysis, excluding seven that were not returned. The collected survey data were subjected to structural equation modeling test using Smart PLS ver. 4.1 statistical package. The results showed that entrepreneurial value orientation and social value orientation positively influenced both economic and social performance. Convergent value orientation was only found to have an effect on economic performance, but not on social performance. Finally, the moderating effect of network capabilities was also found, suggesting that social entrepreneurial orientation positively affects organizational performance when social network capabilities are higher.

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