• 대한의생명과학회지
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• 제22권4호
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• pp.167-173
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• 2016

The broth microdilution technique used to measure the minimal inhibitory concentration (MIC) of natural compounds against bacteria is problematic: it is difficult to visualize bacterial growth due to the color of the natural compound. Therefore, the use of a colorimetric method with a redox indicator by broth microdilution can simplify it and increase its objectivity. This study evaluated the usefulness of the colorimetric method in measuring the MIC of Phellinus baumii against methicillin-resistant Staphylococcus aureus (MRSA). The inhibition in disc diffusion method was observed from $8,192{\mu}g/mL$ P. baumii in all 10 MRSA isolates examined; however, the MIC ranges of the 10 MRSA isolates was $512{\sim}2,048{\mu}g/mL$ by broth microdilution using a colorimetric method; with the 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) indicator. In addition, the MIC of P. baumii by broth microdilution using MTT as indicator yielded excellent results. However, the 2, 3, 5-triphenyltetrazolium chloride (TTC) results could not be determined due to the color of the TTC indicator. The MICs of four antibiotics against MRSA using MTT or TTC were equal to those determined by visual interpretation. In conclusion, to evaluate the antibacterial effects of a natural compound, the broth microdilution technique is considered to be better than the disc diffusion method. Moreover, to resolve the problems caused by the colors of natural compounds, a colorimetric method such as that using MTT may be very valuable.

• 한국경영과학회지
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• 제40권4호
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• pp.107-121
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• 2015

Diffusion of innovation is the process in which an innovation is communicated through certain channels over time among the members of a social system. The literatures have emphasized the importance of interpersonal network influences on individuals in convincing them to adopt innovations and thereby promoting its diffusion. In particular, the behavior of opinion leaders who lead in influencing others' opinion is important in determining the rate of adoption of innovation in a system. Centrality has been recognized as a good indicator that quantifies a node's influences on others in a given network. However, recent studies have questioned its relevance on various different types of diffusion processes. In this regard, this study aims at examining the effect of a node exhibiting high centrality on expediting diffusion of innovations. In particular, we considered the situation where two innovations compete with each other to be adopted by potential adopters who are personally connected with each other. In order to analyze this competitive diffusion process, we developed a simulation model and conducted regression analyses on the outcomes of the simulations performed. The results suggest that the effect of a node with high centrality can be substantially reduced depending upon the type of a network structure or the adoption thresholds of potential adopters in a network.

• Environmental Engineering Research
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• 제23권4호
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• pp.442-448
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• 2018

This paper presents the numerical simulation of advection-diffusion mechanism of BOD concentration which was used as an indicator of waste only in one flow-direction of waste stabilization ponds (1-dimension (1-D)). This model was represented in partial differential equation order 2. The purpose of this paper was to determine the simulation of the model 1-D of wastewater transport phenomena based advection-diffusion mechanism and did validate the model. Numerical methods which was used for the solution of this model is finite difference method with Forward Time Central Space scheme. The simulation results which was obtained would be compared with field observation data as a validation model. Collection of field data was carried out in the Wastewater Treatment Plant Sewon, Bantul, D.I. Yogyakarta. The results of numerical simulations were indicate that the advection-diffusion mechanism takes place continuously over time. Then validation of the model was state that there was a difference between the calculation results with the field data, with a correlation value of 0.998.

• Asian Journal of Atmospheric Environment
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• 제10권1호
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• pp.1-12
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• 2016

Numerous researchers have proposed that surface area is a more appropriate indicator than mass for evaluating pulmonary inflammatory responses caused by exposure to fine and ultrafine particles. In this study, measurements of surface area concentrations of aerosols were conducted in Yokohama, Japan, using the diffusion charging method. $PM_{2.5}$ mass concentration and black carbon concentration in $PM_{2.5}$ were also measured. The 24-hour continuous measurement campaigns were conducted 39 times from March to November, 2014. The surface area concentration was more closely correlated with the black carbon concentration than with the $PM_{2.5}$ mass concentration. It is considered that the abundance of black carbon particles significantly affects the surface area concentration of $PM_{2.5}$. The strength of the correlation between the surface area and black carbon concentrations varied considerably among the measurement campaigns. A relatively weaker afternoon correlation was observed compared with the other time zones (morning, evening, and night). We consider that these phenomena are due to the transportation/formation of the particles other than black carbon that affects surface area concentration and/or the variation of the surface condition of the black carbon particles.

• 정보관리학회지
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• 제23권3호
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• pp.223-239
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• 2006

과학이 기술발전을 이끄는 주요 추진력이며 기술혁신이 궁극적으로 경제발전에 기여한다는 것이 밝혀짐에 따라 선진국은 과학과 기술간 상호작용을 중요하게 다루고 있다. 그러나 한국의 기술발전을 이끈 과학적 기반에 관한 연구가 거의 이루어지지 않았으며 한국의 기술과 강력한 연계를 맺고 있는 학문분야에 대한 연구도 미약한 실정이다. 따라서 이 연구는 특허에 인용된 과학논문을 이용하여 과학기술자의 인용행태를 추적하고, 인용행태 이면에 놓인 과학과 기술간 상호작용을 측정하고자 하였다. 과학논문이 특허의 혁신가치에 어떠한 영향을 미치고 있는지를 살펴봄으로써 기술개발에 있어 과학논문의 중요도를 밝히고자 하였다.

• 유통과학연구
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• 제11권3호
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• pp.39-48
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• 2013

Purpose - This study aims to analyze the main problems of spatial modernization of the economy, and to develop new approaches to way out from crisis, to accelerate of innovations process from the cities-centers to the underdeveloped regions. Research design, data, methodology - The application of scientific methods in this research will allow to systematize the available data, from both a theoretical and empirical perspective. The study employs the method of ranking regions, the rate of innovation activity and comparative evaluation of R&D indicator. In addition, the authors proposed the method of modeling of innovation diffusion in the regions. Results - This study confirms that the need help for the underdeveloped regions, but we should clearly understand the limits of opportunities and to choose the right mechanisms. Further, this study shows it's important to maintain the regions with high innovation activity, as they are growth poles, which are play the role of translator's innovations to the periphery. Conclusions - According to the results of this theoretical and empirical study proved that modernization of the economy is realized faster in the regions with the best conditions for the diffusion of innovations, the higher the concentration of the population, a more developed infrastructure and reduced of administrative barriers.

• 보존과학회지
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• 제7권2호
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• pp.60-67
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• 1998

본 연구는 붕산염 막대(borate rod)를 이용한 고건축물 부재의 부후 구제처리에 대한 기초 연구로서, 소나무와 잣나무에서 붕산염 막대로부터 붕소의 확산시 목재 함수율과 확산기간의 영향을 조사하고자 수행하였다. 함수율이 15, 25, 40%로 조성된 목재 시험편에 1,000 mg의 붕산염 막대를 삽입한 후 상온에서 2, 4, 8, 12주간 확산시키고 붕소 성분의 수축 및 횡단방향 확산정도를 평가하였다. 붕소의 원활한 확산을 위해서는 적어도 섬유포화점 이상의 목재 함수율이 요구되었으며, 또한 확산기간의 연장될수록 붕소의 확산 정도가 증가하였다. 붕소 확산의 이방성이 관찰 되었는데, 수축방향 확산이 횡단방향보다 훨씬 우수하였으며 횡단방향에서는 방사방향 확산이 접선방향보다 우수하였다. 동일 함수율과 확산기간의 조합에서도 확산 정도는 수종간에 조금씩 상이하였는데, 모든 방향에서 잣나무를 통한 확산이 가장 용이하였다. 소나무 심재를 통한 수축방향 확산이 변재를 통한 확산보다 용이하였으며, 횡단방향 확산의 경우는 큰 차이는 없었으나 변재를 통한 확산이 심재를 통한 확산보다 약간 양호하였다. 함수율 40%와 확산기간이 12주인 시험편에 대한 결과를 기준으로 할 때, 붕산염 막대의 수축방향 적정 처리간격은 소나무 심재와 잣나무 심재의 경우는 약 120 mm, 소나무 변재의 경우는 60 mm이고, 횡단방향은 수종에 관계없이 공히 약 30 mm이었다. 그러나 보다 정확한 붕산염 막대의 적정 처리간격을 구명하기 위해서는 앞으로 붕산염 막대의 크기와 장기 확산저장이 붕소 성분의 확산에 미치는 영향에 대한 보다 심도 있는 연구가 필요하다고 생각된다.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.310-315
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• 1997

Wild propionibacteria isolated from different commercial swiss cheese samples were tested for antimicrobial activities. In initial screening, six of these Propionibacterium isolates showed antagonistic activity against 10 selected indicator organisms by the deferred method. In next, only two Propionibacterium strains JW6 and JW14 showed antibacterial activity in the cell-free supernatants by the modified well diffusion method. Propionibacterium strains JW6 and JW14 were finally identified as bacteriocin producers which exhibited a bactericidal effect against closely related species. The antimicrobial substances were proteins, since their activities were completely destroyed following several degradative enzyme treatments. The bacteriocins showed a narrow inhibitory spectrum of activity against two propionibacteria and two bacilli of strains tested in this study.

• 한국경영과학회지
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• 제40권4호
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• pp.49-63
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• 2015

Keyword indexed in multidisciplinary journals show trends about science and technology innovation. Nature and Science were selected as multidisciplinary journals for our analysis. In order to reduce the effect of plurality of keyword, stemming algorithm were implemented. After this process, we fitted growth curve of keyword (stem) following bass model, which is a well-known model in diffusion process. Bass model is useful for expressing growth pattern by assuming innovative and imitative activities in innovation spreading. In addition, we construct keyword co-occurrence network and calculate network measures such as centrality indices and local clustering coefficient. Based on network metrics and yearly frequency of keyword, time series analysis was conducted for obtaining statistical causality between these measures. For some cases, local clustering coefficient seems to Granger-cause yearly frequency of keyword. We expect that local clustering coefficient could be a supportive indicator of emerging science and technology.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.393-398
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• 2021

Current risk assessment of Spent Nuclear Fuel (SNF) transportation has the problem of the incomplete risk factors consideration and the general particle diffusion model utilization. In this paper, the accident frequency calculation and the detailed simulation of the accident consequences are coupled by the integrated risk assessment method. The "man-machine-environment" three-dimensional comprehensive risk indicator system is established and quantified to characterize the frequency of the transportation accidents. Consideration of vegetation, building and turbulence effect, the standard k-ε model is updated to simulate radioactive consequence of leakage accidents under complex terrain. The developed method is applied to assess the risk of the leakage accident in the scene of the typical domestic SNF Road Transportation (SNFRT). The critical risk factors and their impacts on the dispersion of the radionuclide are obtained.