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        검색결과 52

        1.
        2023.11 구독 인증기관·개인회원 무료
        For safe disposal of radioactive wastes, accurate analysis of nuclear isotopes is important. It is known that there are 14 nuclides that have to identify nuclide-specific concentration levels. 63Ni, one of non-volatile nuclear isotopes which is included in those 14 nuclides, has to follow chemical separation for exact analysis. As various analysis methods were developed, various methods for analyzing 63Ni also emerged. Past method has used measurement specimens of 59Ni, after 59Ni measurement has been done. It used HClO4, known as strong oxidizing agent, to dissolve DMG, an organic substance used to form 59Ni precipitates. Nowadays, we analyze 59Ni and 63Ni simultaneously, which enables short analysis time, without use of HClO4. But high accuracy is just as important as short measurement time and efficiency. So, this paper compare 63Ni specific activity value used new method with the value, past method used, using real sample’s data. As a result, all sample data from new method’s relative 63Ni specific activity is within the uncertainty range of past ones based on past specific activity value. Consistency of new method’s result and past method’s data increased the reliability of the data and accuracy of those methods.
        2.
        2023.11 구독 인증기관·개인회원 무료
        The domestic Pressurized Heavy Water Reactor (PWHR) nuclear power plant, Wolsong Unit 1, was permanently shut down on December 24, 2019. However, research on decommissioning has mainly focused on Pressurized Water Reactors (PWRs), with a notable absence of both domestic and international experience in the decommissioning of PHWRs. If proper business management such as radiation safety and waste is not performed, it can lead to increased business risks and costs in decommissioning. Therefore, the assessment of waste volume and cost, which provide fundamental data for the nuclear decommissioning process, is a crucial technical requirement before initiating the actual decommissioning of Wolsong Unit 1. Decommissioning radiation-contaminated structures and facilities presents significant challenges due to high radiation levels, making it difficult for workers to access these areas. Therefore, technology development should precede decommissioning process assessments and safety evaluations, facilitating the derivation of optimal decommissioning procedures and ensuring worker safety while enhancing the efficiency of decommissioning operations. In this study, we have developed a program to estimate decommissioning waste amounts for PHWRs, building upon prior research on PWR decommissioning projects while accounting for the specific design characteristics of PHWRs. To evaluate the amount of radioactive waste generated during decommissioning, we considered the characteristics of radioactive waste, disposal methods, packaging container specifications, and the criteria for the transfer of radioactive waste to disposal operators. Based on the derived algorithm, we conducted a detailed design and implemented the program. The proposed program is based on 3D modeling of the decommissioning components and the calculation of the Work Difficulty Factor (WDF), which is used to determine the time weighting factors for each task. Program users can select the cutting and packaging conditions for decommissioning components, estimate waste amount based on the chosen decommissioning method, and calculate costs using time weighting factors. It can be applied not only to PHWRs, but also to PWRs and non-nuclear fields, providing a flexible tool for optimizing decommissioning process.
        3.
        2022.10 구독 인증기관·개인회원 무료
        With the aging of nuclear power plants (NPPs) in 37 countries around the world, 207 out of 437 NPPs have been permanently shutdown as of August 2022 according to the IAEA. In Korea, the decommissioning of NPPs is emerging as a challenge due to the permanent shutdown of Kori Unit 1 and Wolsong Unit 1. However, there are no cases of decommissioning activities for Heavy Water Reactor (HWR) such as Wolsong Unit 1 although most of the decommissioning technologies for Light Water Reactor (LWR) such as Kori Unit 1 have been developed and there are cases of overseas decommissioning activities. This study shows the development of a decommissioning waste amount/cost/process linkage program for decommissioning Pressurized Heavy Water Reactor (PHWR), i.e. CANDU NPPs. The proposed program is an integrated management program that can derive optimal processes from an economic and safety perspective when decommissioning PHWR based on 3D modeling of the structures and digital mock-up system that links the characteristic data of PHWR, equipment and construction methods. This program can be used to simulate the nuclear decommissioning activities in a virtual space in three dimensions, and to evaluate the decommissioning operation characteristics, waste amount, cost, and exposure dose to worker. In order to verify the results, our methods for calculating optimal decommissioning quantity, which are closely related to radiological impact on workers and cost reduction during decommissioning, were compared with the methods of the foreign specialized institution (NAGRA). The optimal decommissioning quantity can be calculated by classifying the radioactivity level through MCNP modeling of waste, investigating domestic disposal containers, and selecting cutting sizes, so that costs can be reduced according to the final disposal waste reduction. As the target waste to be decommissioning for comparative study with NAGRA, the calandria in PHWR was modeled using MCNP. For packaging waste container, NAGRA selected three (P2A, P3, MOSAIK), and we selected two (P2A, P3) and compared them. It is intended to develop an integrated management program to derive the optimal process for decommissioning PHWR by linking the optimal decommissioning quantity calculation methodology with the detailed studies on exposure dose to worker, decommissioning order, difficulty of work, and cost evaluation. As a result, it is considered that it can be used not only for PHWR but also for other types of NPPs decommissioning in the future to derive optimal results such as worker safety and cost reduction.
        4.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 2006년부터 2019년까지 개최된 경관 조성용 화 훼를 주제로 하는 지역축제의 시기 및 지역에 따른 변화와 화 훼류의 이용 및 생산현황 분석을 통해 향후 경관화훼 연구에 대한 기초자료를 제공하고자 수행하였다. 2006년부터 2019년 까지 개최된 지역축제 10,800건 중 경관화훼 관련 축제를 시 기별 및 지역별 개최수와 활용된 식물의 종류와 생산현황을 분석하였다. 지역축제 10,800건 중 꽃축제는 1,312건으로 연 평균 94건이 개최되었으며 지역축제의 12.1%를 차지하였다. 지역축제는 2008년 최고점에서 감소하다 2014년 이후 지속적 으로 상승하고 있는 반면 꽃 축제의 비율은 2008년에서 2010 년까지 소폭 감소하였다가 지속적으로 높아져 2019년에는 15.5%를 차지하였다. 계절별 평균적인 개최비율은 봄 66.7%, 가을 25.7%, 여름 6.8%, 겨울 0.8%로 봄에 가장 많이 집중되 었으며, 여름과 겨울에는 매우 적게 나타났다. 지역별로 살펴 봤을 때 전남은 매년 평균 18건으로 개최수가 많을 뿐만 아니 라 2010년 이후 지속적으로 늘어나는 경향을 보인 반면 경남 의 경우는 매년 평균 10건으로 2010년 이후 지속적으로 감소 하다 2016년부터 증가하였다. 이외에 강원도, 경기도, 서울, 전북, 충남 등에서 매년 평균 9건 정도가 개최되었으며 그 다 음으로 충북, 경북, 제주도, 대구 등에서 3~4건이 개최되었고, 인천, 울산, 부산, 광주, 대전 등은 2건 이하로 전반적으로 대구를 제외한 광역시에서 꽃 관련 축제가 적은 것으로 나타났 다. 인터넷으로 검색된 소규모 축제를 포함하였을 때 2019년 개최건수는 경기도(49건), 전남(40건), 서울(28건), 제주도(25 건), 충남(25건), 경남(24건), 강원도(17건), 경북(12건) 등으로 나타났다. 경관용 화훼류는 목본류가 연평균 51건의 꽃축제에 서 주제식물로 활용되었으며, 일년초(11건), 그래스(9건), 숙 근초(8건), 수생식물(3건), 구근류(3건) 순으로 나타났다. 주제 식물은 목본류(12종), 일년초(4종), 관상용 그래스(4종), 다년 초(3종), 구근류(3종)으로 26종이 사용되었으며, 구근류를 제 외한 대부분의 식물이 2~4개의 축제에서 중복으로 활용되었 다. 경관조성용 화훼생산량은 경남, 전남, 울산, 경북, 전북, 강원도, 경기도, 충북, 충남 순으로 나타났다. 품목별로는 국 화와 메리골드가 100만분 이상, 팬지류와 페튜니아는 50만분 이상, 색양배추, 베고니아, 백일홍, 패랭이류, 샐비아, 맨드라 미 등이 10만분 이상 생산되었다.
        4,000원
        6.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험은 장미의 삽목시 증산억제제와 생장억제제를 활용 하여 미스트나 밀폐시설 없이 삽목발근 효율을 증가시킬 목적으로 수행하였다. 절화장미 ‘M-Red’ 줄기 삽목 후 증산억제제 ‘Wilt Pruf’ 및 ‘Cloud Cover’ 1, 2, 4, 8%와 생장억제제 paclobutrazole 10, 20, 40, 80mg・L-1, diniconazole 100, 200, 400, 800mg・L-1를 각각 엽면살포 하였다. 증산억제제의 효과 는 종류에 따라 달랐는데, Wilt Pruf는 생존율, 신초 발생율, 발근율을 모두 향상시켰으나 신초수, 뿌리수, 뿌리길이에는 영향을 미치지 않았다. Cloud Cover는 생존율과 발근율을 향상시키는 효과가 없었으나 신초 발생율이 처리농도와 비례하여 높아져 4, 8% 처리시 가장 높게 나타났다. 생장억제제 처리효과도 종류에 따라 달라 paclobutrazol은 생존율과 발근율 향상에 영향을 미치지 않았으나 신초 발생율을 높였으며 1% 처리시에 신초발생이 가장 높았다가 농도가 높아지면서 낮아졌다. Diniconazole은 100, 200mg・L-1 처리시 생존율과 발근율을 향상시켰으나 800mg・L-1의 고농도에서는 생존율과 발근율 모두 낮게 나타났다.
        4,000원
        8.
        2020.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        축산 폐수는 고농도의 영양염류와 중금속을 함유하고 있어, 배출될 때 수질을 악화시킨다. 기존 처리 기술과 비교하여 bioremediation은 축산 폐수 처리에 유능하다. 특히, 미세조류는 오염물질 제거에 잠재력을 가지고 있다. 본 연구에서는 Ankistrodesmus bibraianus를 이용하여 축산 폐수 내 영양염류 (질소 (N), 인 (P))와 중금속 (구리 (Cu), 아연 (Zn))의 제거 가능성을 평가하고, A. bibraianus의 최적배양조건을 확립하였다. 연구결과, 최적 배양조건은 28°C, pH 7, 광주기는 14 : 10 h로 설정되었다. N과 P의 단일 처리구 (500, 1,000, 5,000, 10,000 mg L-1)에서 제거효율은 각각 22.9~80.6%와 11.9~50.0%였다. 또한, N과 P의 복합 처리구에서 제거효율은 각각 16.4~58.3%와 7.80~49.8%였다. Cu와 Zn의 단일 처리구 (10, 30, 50 mg L-1)에서 제거효율은 각각 15.5~81.5%와 6.28~34.3%였다. 유사하게, Cu와 Zn의 복합 처리구에서 제거효율은 각각 16.7~74.5%와 5.58~27.5%였다. 또한 영양염류 (N 및 P)와 중금속 (Cu 및 Zn)의 성장 및 제거효율을 축산 폐수에 적용할 수 있음을 나타냈다. 본 연구의 결과에 따르면 A. bibraianus는 축산 폐수 내 영양염류와 중금속 제거에 이용할 수 있을 것으로 사료된다.
        4,200원
        10.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to identify the effects of cervical alignment, pain, and physique to apply proprioceptive neuromuscular facilitation( PNF) techniques in patients with forward head posture (FHP). The subjects of this study were 24 patients diagnosed with FHP. They were randomly divided into two groups: a PNF group(n=12) and a control group(n=12). The intervention was performed a total of 24 times, 30 min a day, six times a week for four weeks. Data on cervical alignment(forward head displacement, FHD), pain(visual analog scale, VAS), and physique(height, weight, and body mass index) were obtained pre- and post-intervention. Two-way repeated measures ANOVA was used to compare the groups and time. For FHD, the VAS, and physique(height and BMI), there was an interaction effect for the groups and time(p<.001, BMI: p<.05) and main effects for time(p<.001, BMI: p<.05). For weight, there were main effects of time(p<.01). For FHD(p<.01) and the VAS(p<.05), there were main effects for the groups. In the PNF group, there were significant improvements in FHD, VAS, and physique. In the control group, there was a significant increase in FHD. The results of this study indicated that PNF intervention using scapular and upper extremity patterns effective in FHP positively. The use of a therapeutic intervention on physique changes may also be effective in improving poor posture and help to better patients’ quality of life.
        4,000원
        12.
        2015.06 구독 인증기관·개인회원 무료
        Selfie refers to self-portrait photography, which became widespread practice with handy digital photographing technologies and the proliferation of social media. There are only a few studies on selfie and most of them examine the psychological profiles of selfie takers. However, we conducted a qualitative study to understand diverse goals embedded in the selfie practice and meanings of the practice. Eighty one undergraduate students enrolled in a university in South Korea, who reported to take selfies frequently, were recruited for in-depth interviews. Semi-structured interviews were conducted for thirty minutes to an hour, asking their selfie-taking behaviors including general information (when, where, how, why), skills and techniques, related memories and experiences, and sharing and online posting. Transcripts and observations were analyzed through multiple steps of coding. Data revealed numerous strategies in selfie photography and statements about why those strategies are important, that is, goals of selfie practice. We present findings in the following structure: Operation of selective selves → Subordinate goals → Superordinate goals We abstract the essential feature of selfie as augmented control as a result of integrative and selective operation of the three selves as the one who photographs, the one who is photographed, and/or the one who owns and uses the selfie. Participants’ strategies reflect this complexity. For example, tips for camera angles and lighting are related to self as a subject who photographs. Knowledge on facial expressions reflects self as an object that is photographed. Photoshop skills are obtained as self who uses the photographs. Five goals at the subordinate level emerged: Attractive appearance, social activities, testimonial, fact check, and story-telling. These are the immediate goals gained through taking, using, and possessing selfies. Different goals are formed based on relatively different importance of each of the three selves. For example, to post a selfie that tells one’s feeling about new season, the photographer chooses to focus on the self as a subject who writes a story and portrays in photographing rather than the self as an object of the photograph. Superordinate goals are derived from the subordinate goals: Narcissism, self-discovery, self-expression, reminiscence, display, self-monitoring, and belongingness. As in the relations between selves and subordinate goals, some subordinate goals are related to more than one superordinate goal. Some superordinate goals also result from more than one subordinate goal. We conclude that selfie provides augmented control in producing and using pictures and the selective operation of the three selves enables consumers to obtain various individual and social values through the selfie practice.
        13.
        2002.10 구독 인증기관 무료, 개인회원 유료
        We propose an efficient algorithm to find and update sequential patterns when new transactions are added to an existing database. This method reduces time for scanning the existing and new databases since it uses only transactions that influence the length of sequence. This algorithm outperforms existing algorithm when updated sequential pattern found in the whole database are longer than the patterns in the existing database. Experimental results show the reduction in total execution time.
        4,000원
        14.
        2021.11 KCI 등재 서비스 종료(열람 제한)
        In this study, the effects of single and binary heavy metals toxicity on the growth and phosphorus removal ability of Bacillus sp.. known as be a phosphorus-removing microorganism, were quantitatively evaluated. Cd, Cu, Zn, Pb, Ni were used as heavy metals. As a result of analysis of variance of the half of inhibition concentration and half of effective concentration for each single heavy metal treatment group, the inhibitory effect on the growth of Bacillus sp. was Ni < P b < Z n < Cu < C d. A nd the inhibitory effect on phosphorus removal by Bacillus s p. w as N i < Pb < Z n < Cu < C d. When analyzing the correlation between growth inhibition and phosphorus removal efficiency of a single heavy metal treatment group, a negative correlation was found (R2 = 0.815), and a positive correlation was found when the correlation between IC50 and EC50 was analyzed (R2 = 0.959). In all binary heavy metal treatment groups, the interaction was an antagonistic effect when evaluated using the additive toxicity index method. This paper is considered to be basic data on the toxic effects of heavy metals when phosphorus is removed using phosphorus removal microorganisms in wastewater.
        15.
        2021.02 KCI 등재 서비스 종료(열람 제한)
        This study was initiated to isolate the microorganisms removing phosphorus (P) from domestic sewage and to investigate the effects of environmental factors on the growth and P removal of the isolated bacteria. Microorganisms isolated from the sewage were identified as Chryseobacterium sp., Stenotrophomonas maltophilia, and Bacillus licheniformis. Among them, Bacillus licheniformis was selected as the P removal microorganism. The environmental factors considered in this study included initial phosphorus concentration, temperature, pH, and carbon source. At initial P concentrations of 10, 20, and 30 mg/L, the P removal efficiencies were 100.0%, 84.0%, and 16.5%, respectively. At 20°C, 30°C, and 40°C, the P removal efficiencies were 0%, 75.8%, and 60.6%, respectively. The removal efficiencies of phosphorus according to pH were 1.6%, 91.7%, and 51.1% at pH 5, pH 7, and pH 9, respectively. Using glucose, acetate, and glucose + acetate as carbon sources yielded P removal efficiencies of 80.9%, 33.6%, and 54.1%, respectively. Therefore, the results from the study demonstrated that the P removal efficiencies of Bacillus licheniformis were the highest when the initial P concentration, temperature, pH, and carbon source were 10 mg/L, 30°C, 7, and glucose, respectively.
        16.
        2020.03 KCI 등재 서비스 종료(열람 제한)
        This study was conducted to evaluate the effect of phosphorus acid (H3PO3) addition to the horticultural bed soil on the initial growth of red pepper (Capsicum annuum L. cv.), cucumber (Cucumis sativus L. cv.), and kimchi cabbage (Brassica campestris L. ssp. pekinensis (Lour.) Rupr. cv.). The stem heights of red pepper and cucumber were 46.1% and 23.0% greater in the 50 mg/L of phosphorus acid treatment than the untreated (control). Further, the stem diameter of pepper and cucumber were 48.7% and 23.0% greater in the 50 mg/L of phosphorus acid treatment than the control. In addition, the number of kimchi cabbage leaves was 47.5% greater in the 50 mg/L of phosphorus acid treatment than the control. The dry weights of red pepper, cucumber and kimchi cabbage were 72.9%, 16.5%, and 30.4% heavier in the 50 mg/L than the control, respectively. Cations (K, Ca, and Mg) and total phosphorus (T - P) were quantitatively analyzed for these three horticultural crops. The concentrations of K, Ca, and Mg, and T - P were higher in the 50 mg/L of phosphorus acid than the control, respectively. Based on the results obtained in this study, it appears that treatment of phosphorus acid in horticultural bed soil enhanced the growth of red pepper, cucumber and Kimchi cabbage.
        17.
        2018.11 KCI 등재 서비스 종료(열람 제한)
        Bioremediation has been recognized as a suitable alternative to conventional methods of removing contaminants, and it uses fungi, bacteria and microalgae. In contrast to other organisms, microalgae are unique in that they have the ability to perform photosynthesis like plants and to utilize organic/inorganic carbon substrates, in a process called phytoremediation. Microalgae can populate a reaction site rapidly and enhance the bioremediation efficiency. In this study, Chlorella vulgaris was used to evaluate the removal potentials of the nutrients (N and P) and heavy metals (Cu and Zn) from swine wastewater. The optimum growth conditions for Chlorella vulgaris and the removal potentials of N, P, Cu, and Zn from synthetic wastewater using Chlorella vulgaris were investigated. Based on the results, the applicability of this microalga to on-site wastewater treatment was examined. Optimal growth conditions for Chlorella vulgaris were established to be 28℃, a pH of 7, and light and dark cycles of 14:10 h. As the concentrations of the nutrients were increased, the efficiencies of N and P removal efficiencies by Chlorella vulgaris were decreased in the single and binary mixed treatments of the nutrients, respectively. Further, the efficiencies of Cu and Zn removal also decreased as the heavy metals concentrations added were increased, both in the single and binary mixed treatments. In addition, the efficiency of Cu removal was higher than that of Zn removal. Our results indicate that Chlorella vulgaris could be used in treatment plants for the removal of nutrients and heavy metals from swine wastewater.
        18.
        2016.12 KCI 등재 서비스 종료(열람 제한)
        The present study was conducted to establish the optimal fertilization type and method for no-tillage during the first year of No-tillage (NT) and Conventional-tillage (CT) practices for soybean, using different types of fertilizers. In this experiment, the culm length and stalk diameter showed a greater response to fertilization with surface irrigation than to conventional fertilization. The fastest flowering period (July 28) occurred using chemical fertilization applied via subsurface irrigation. Comparing maturation based on growth characteristics and flowering date revealed that fertilization with subsurface irrigation was more effective for the growth of crops than other methods. Regarding yield, there was no significant difference between livestock and chemical fertilizers in subsurface irrigation, but there were significant differences between these fertilizers when using conventional fertilization methods. Based on the results, livestock fertilizer with subsurface irrigation effectively enhanced crop quantity. Nitrogen absorption of plants using subsurface irrigation was more effective than that using conventional fertilization. Regarding phosphorus absorption of plants, chemical fertilizers showed higher absorption than did livestock fertilizers for both subsurface irrigation and conventional fertilization. Unlike nitrogen, phosphorus was highly absorbed using conventional fertilization. Absorption of phosphorus and potassium were similar but phosphorus was not absorbed using livestock fertilizers applied either using subsurface irrigation or with conventional fertilization.
        19.
        2015.08 KCI 등재 서비스 종료(열람 제한)
        Purpose: Using the self-determination theory, this study examined both the mediating effects and the specific indirect effects of the satisfaction of the three psychological needs (need for autonomy, competence and relatedness) and intrinsic motivation in the relation between need support from the physical education (PE) teacher and engagement in PE classes. Method: Participants were 523 high school students (251 males, 272 females) and completed questionnaire assessing perceived need support, need satisfaction, intrinsic motivation and engagement in PE classes. Results: Structural equation modeling analysis showed perceptions of the three need satisfaction partially mediated the relation between need support from PE teacher and engagement in classes. Moreover, the indirect effect of intrinsic motivation was larger than those of the three psychological need satisfaction. Conclusion: These findings suggest that PE teacher is able to promote students' intrinsic motivation by satisfying their needs for autonomy, competence and relatedness. The findings supported the theoretical tenets of self-determination theory as well.
        20.
        2015.05 KCI 등재 서비스 종료(열람 제한)
        Purpose: The purpose of this study was to test a 2×2 model of perfectionism among dancers. Methods: Dancers(N=538, male=95, female=443) completed measures of multidimensional perfectionism(self oriented and socially prescribed perfectionism), cognitive appraisals(challenge and threat), emotion regulations(reappraisal and suppression). Results: Moderated hierarchical regression and simple slope analysis indicated that dance majors with pure self oriented perfectionism were related to higher emotion regulation(reappraisal and suppression) than dance majors with non perfectionism. Dance majors of mixed perfectionism were related to higher challenge(cognitive evaluation), emotion regulation(reappraisal and suppression) than dance majors of pure socially prescribed perfectionism. Furthermore, dance majors of were associated with higher levels of threat(cognitive evaluation) than dance majors with pure self oriented perfectionism. Conclusion: The results of this study partially support the predictions of the 2×2 model of perfectionism in dance.
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