• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.60-67
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• 2013

A diffusion coefficient is an important parameter in the prediction of atmospheric dispersion using a Gaussian plume model, and its modelling approach varies. In this study, dispersion coefficients recommended by the U. S. Nuclear Regulatory Commission's (U. S. NRC's) regulatory guide and the Canadian Nuclear Safety Commission's (CNSC's) regulatory guide, and used in probabilistic accident consequence analysis codes MACCS and MACCS2 have been investigated. Based on the atmospheric dispersion model for a hypothetical accidental release recommended by the U. S. NRC, its influence to atmospheric dispersion factor was discussed. It was found that diffusion coefficients are basically predicted from a Pasquill- Gifford curve, but various curve fitting equations are recommended or used. A lateral dispersion coefficient is corrected with consideration for the additional spread due to plume meandering in all models, however its modelling approach showed a distinctive difference. Moreover, a vertical dispersion coefficient is corrected with consideration for the additional plume spread due to surface roughness in all models, except for the U. S. NRC's recommendation. For a specified surface roughness, the atmospheric dispersion factors showed differences up to approximately 4 times depending on the modelling approach of a dispersion coefficient. For the same model, the atmospheric dispersion factors showed differences by 2 to 3 times depending on surface roughness.

• Journal of The Korean Association For Science Education
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• v.34 no.1
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• pp.33-42
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• 2014

There are complex interactions between personal and contextual features in teaching in a science museum. In order to analyze two teachers' holding classes in a science museum, the CHAT (cultural historical activity theory) was used as an analysis tool in a case study. The analyses of the results revealed that both teachers had difficulties teaching in a science museum due to the contradictions among the factors of subject, rules, community, and division of labor in the activity system. Although both teachers had trouble with similar contradictions, there appeared to be different sets of internalization and externalization of such conflicts depending on the difference in the teacher's perceptions and experiences about teaching in a science museum, the passion and the motivation of the teachers. These suggested that efforts should be preceded to foster the activity system providing both emotional and social supports to teachers in order to activate teaching in a science museum. Taking a teacher training course on teaching in a science museum was also found to fail to function as mediating artifacts. The course should provide not only the experience of executing proper teaching strategies for teaching in a science museum and the feedback on their teaching, but also the guidance on how to lead to optimal expansion of the factors in the activity system.

• Journal of The Korean Association For Science Education
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• v.38 no.2
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• pp.171-186
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• 2018

Recent research has shown that elementary school students can experience epistemic affect -emotions and feelings experienced within epistemic practices, such as the enjoyment of having a wonderful idea or uncomfortable feeling of at a cognitive dissonance- during modeling process. This study explores how an introverted elementary student could participate in the modeling process by constructing an epistemic affect. Based on the theory of constructed emotion, we analyzed one elementary student's constructed epistemic affect using data resources such as emotion diaries, video recordings, and post interviews. We selected one introverted student (a fifth grader), showing peripheral and full participation during modeling. Specifically, we explored which emotions were constructed when she participated in modeling peripherally -and which epistemic affect was constructed when she participated fully- during the construction, evaluation, and revision processes. The research results showed, first, that the introverted elementary student came to participate in the model construction process by constructing the epistemic affect called aha. Second, the results showed that she came to participate in the model revision process by constructing the epistemic affect called feeling that the reasoning was wrong when confronting the rebuttals of the other student. Finally, she came to participate in the model evaluation process by constructing the epistemic affect called dislike of another student's idea. Through our exploration of the constructed epistemic affect of the introverted elementary student, we deduced that it is important to help each student to construct an epistemic affect that facilitates his or her participation in modeling. Also, we discussed that it is important to understand the impact of the emotional load that can occur for each student, depending on the constructed past, present, and future emotions.

• Journal of The Korean Association For Science Education
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• v.40 no.1
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• pp.1-12
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• 2020

In scientific argumentation, students can use rebuttals to escape uncertainty, which, in this case, can be defined as a vague and fuzzy feeling about other students' explanations. As rebuttals can play a critical role in the sophistication of arguments and the alleviation of uncertainty, this study aims to understand the dynamics of uncertainty and rebuttals by exploring the context of the uncertainty experienced by elementary school students in the argumentation of "Why did the kidney beans not germinate?" and to get insights based on the research results. Twenty fourth-grade students and their homeroom teacher in Kyong-Ki province, South Korea, took part in the research. Students engaged in argumentation in five small groups of four students. The researcher collected qualitative data through video transcriptions, student interviews, and field notes. In the data analysis, the researcher employed the constant comparative method to explore in what context students experienced uncertainty and how they used rebuttals. The results of this study were as follows: First, students tried to reduce their uncertainty through argumentation on why the kidney beans did not germinate. Second, students used elaboration-oriented rebuttals, personal opinion-oriented rebuttals, and blame-oriented rebuttals to reduce this uncertainty. However, when they used blame-oriented rebuttals, their uncertainty and negative emotions increased. Third, intervention by the teacher led students to stop using blame-oriented rebuttals. Instead, they employed elaboration-oriented rebuttals to explore why the kidney beans would not sprout, and finally, they escaped uncertainty by discovering an appropriate explanation. Based on the findings of this study, the researcher discussed how the interaction between uncertainty and elaboration-oriented rebuttals could shape and facilitate argument development in elementary school students.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.21-26
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• 2002

For the consideration of the influence on radioactive contamination of foods due to rain during the release period of radionuclides in a nuclear accident, the previous dynamic food chain model was improved. Wet interception coefficients for the agricultural plants were derived as a function of radionuclide and rainfall amount, and mathematical formula of the model was also re-established. In the results for the same time-integrated radioactive concentrations on the ground, radioactive contamination of foods decreased greatly by rainfall, and it decreased dramatically according to increasing rainfall amount. It means that predictive contamination in foods using the previous dynamic food chain model, in which dry interception to the agricultural plants is only considered, can be overestimated. Among radionuclides considering in this study ($^{137}Cs,\;^{90}Sr,\;^{131}I$), influence of rainfall for food contamination was the most sensitive to $^{131}I$, and the least sensitive to $^{90}Sr$.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.7-13
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• 2000

Purpose : To assess the distortion of MRI with the Leksell stereotactic radiosurgery system in variable pulse sequence and imaging plane through phantom study, to find most adequate imaging plane and pulse sequence for stereotactic radiosurgery system. Materials and methods : We made the phantoms for MRI and get images in variable conditions and analyzed the image distortion using image analysis program, and statistically using paired student t-test. Results : The transeverse plane images had acceptable error ranges bless than 1.5mm) in all pulse sequence in both the analysis of fiducial marker in stereotactic G-frame and the phantom study. The coronal plane images had unacceptable large errors (more than 1.7mm) in the analysis of fiducial marker in the stereotactic G-frame, but had corrected small errors (less than 1.5mm) in the phantom study. Conclusion : We find from the phantom study that the present MR machines are adequate for stereotactic surgery system in frequently used pulse sequences, and imaging planes.

• Journal of Life Science
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• v.27 no.6
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• pp.702-707
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• 2017

Insects and their extract have been traditionally used as medicinal resources in Asia. Recently, Gryllus bimaculatus and the larva of Tenebrio molitor, Protaetia brevitarsis, and Allomyrina dichotoma were enlisted as general food ingredients by Korean Ministry of Food and Drug Safety. As the interest in these insects is growing, the detailed investigation is needed for the standardization of suitable and safe rearing techniques. This survey was conducted via personal interviews about edible insect rearing farms in Korea. The basic feed is fermented oak sawdust for P. brevitarsis and A. dichotoma and wheat bran for T. molitor. The various feed additives are blended with each farm's own recipes. The overall growth condition, including sawdust fermentation method, feeding period, and rearing density, varies among the investigated farms. It seems that weight of last instar larva was correlated with the rearing density and duration of the larval period. The heavy metal contents were analyzed after 48 hour starvation and they were very small amount or not detected in investigated insects. We believe that the present data will contribute to develop and standardize the safe rearing techniques of edible insects in Korea.

• Investigative Magnetic Resonance Imaging
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• v.7 no.1
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• pp.31-38
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• 2003

Purpose : To analyze the serial changes of proton magnetic resonance (MR) spectra in the abscess and to determine the effect of the antibiotic treatment on the metabolite patterns. Materials and Methods : MR imaging and MR spectroscopy of an experimentally induced abscess were performed sequentially for four weeks at interval of one week in both the control group (n=5) and the antibiotic treatment group (n=5). On MR imaging, the shape and the size of the abscess were analyzed. On MR spectroscopy, the resonance peaks of metabolites were assigned on the basis of reported peaks in the literature. The metabolite ratios measured by using N-acetyl alanine as an external reference and by using lipid as an internal reference were compared in both the control and treatment g roups. Results : The abscesses were seen as cystic masses on MR imaging. On MR spectroscopy, the variable peaks of acetate, succinate and various amino acids, which are the metabolites of infection, were identified in the control and antibiotic treatment groups. The most frequent peak was that of acetate at 1.92ppm (70%). Both the peak ratios of acetate to lipid and acetate to external reference tended to decrease in the treatment group while the ratios did not change significantly in the control group. Conclusion : MR spectroscopy is useful not only for the diagnosis of abscess but also for monitoring the evolution of the abscess by using the acetate peak.

• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.193-204
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• 2020

According to science technology development, information society has progressed rapidly in the 21st century. Our consciousness and tradition have become entangled in the tide of Westernization. Therefore, the education of Chinese characters was neglected, and Chinese poetry literature was naturally neglected. This led to the abundance of material civilization, however, from the mental aspects, the daily life of modern people became insecure. There is a poet who has lived a lonely life of creation of Chinese poetry in this era. He is a Geasan Kwon Seung Geun(1940~) who writes only poem while being friends with nature. His Chinese poems were revealed through life experiences in nature, which is inspiring sympathy. The origin of his theme is nature. The poetry obtained from nature is rustic simple and pure. Therefore His poems have the style and taste of nature. The Chinese poetry literature of Geasan has been embodied the elements of self-interest, self-satisfaction, self-contentment and living in free at his literatue. On its basis, his Chinese literature has aesthetic boundary of remaining aloofness(自然而然的 超然)·rambling talk, living peacfully and play around with leisure·(閒遠物遊的 閑淡)·deviation rhyme of vividly and beautifully(生趣淸遠的 逸韻) The aesthetic boundary of Chinese poetry of Geasan can be seen as having a depth. This is the aesthetic boundary of Chinese poetry written by this generation in the 21st century.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.2 no.1
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• pp.11-23
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• 1991

The main purpose of this study was to investigated the relationship between test anxiety and academic performance, additionally to examine the sexual and developmental differences in test anxiety. Test anxiety was assessed by the TAI-K(Kim Moonjoo, 1990) and was done to 388 3rd, 4th, 5th, 6th, grades and 104 9th grades. The level of TAI-K scores devided into a threeway split or five-way split. In the case of elementary school, four main cognitive subject-areas makes(the mean sum of semester) were used as academic performance indicator and with secondary school, all twelve subject-areas were included. The data were processed by correlational analysis and one-way ANOVA. The Results of this study are as follws : 1) Test anxiety correlated negatively and significantly with academic performance. While in the case of elementary school, in four cognitive subject-areas(Korean, Mathmatics, Society and Physics), two variables showed negative relationship, it was shown negatively in six subject-areas among twelve by secondary students. 2) In the area of sexual differences in test anxiety, female showed significantly higher level than male in elementary school however, there were no significant differences in secondary school. 3) In the area of developmental differences in test anxiety, in the case of elementary school. there were no significant differences between four grades.