• Analytical Science and Technology
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• v.37 no.3
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• pp.143-154
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• 2024

In this study, we improved the vitamin C test method and reviewed data on the adjustable range of chromatography conditions for quantification. First, we adjusted the mobile phase conditions such as solvent composition, salt concentration, pH and column temperature and in particular, it was confirmed through an improved test method that the peak derived from the buffer solution could be clearly separated from the target component, vitamin C by adjusting the pH. The retention time of vitamin C was partially changed by adjusting the column diameter, length and particle size but the number of theoretical plates indicated similar values and did not affect the separation and quantitative analysis of the target component. The flow rate according to the column specifications was derived from the equation proposed by the U.S. FDA (Food and Drug administration) and the Korean MFDS (Ministry of Food and Drug Safety), and evaluation of the applicability to vitamin complexes showed high selectivity for vitamin C even with altered stationary phase conditions and flow rates. In conclusion, vitamin C can be optimally separated and detected by changing the chromatographic method conditions and it was confirmed that the mobile and stationary phase conditions of liquid chromatography can be slightly adjusted in case the assay method uses an isocratic elution.

• Journal of the Korean Geotechnical Society
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• v.40 no.3
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• pp.93-100
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• 2024

Pore water freezes in low-temperature compaction, which leads to different compaction characteristics compared to room temperature conditions. In regions like Alberta, Canada, where organic soils are prevalent, compaction performance is influenced by the high water retention and compressibility of organic soils, as well as their sensitivity to freezing and thawing. Alberta's strict environmental regulations demand the reuse of excavated soil for backfill, and the long winter season creates challenging conditions for civil engineering projects. In this study, a laboratory compaction test was conducted to evaluate the low-temperature compaction characteristics of organic soils with varying organic content. The results indicate that the optimum moisture content increases as the organic content increases, and the maximum dry unit weight decreases by up to 21.9%. In addition, under temperature conditions below -4℃, no optimum moisture content was observed, and the dry unit weight decreased as the moisture content increased.

• Analytical Science and Technology
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• v.37 no.3
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• pp.155-165
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• 2024

This study aimed to assess whether plant-based meat substitutes can effectively replace animal meat products in terms of amino acid composition and zinc bioavailability. The evaluation was conducted in response to the growing demand for meat substitutes, driven by the increasing vegan population and the expansion of vegan culture. For this purpose, a chicken product and two plant-based meat substitutes in tender form were selected. The amino acid content and composition were measured using HPLC, while the levels of trace elements like zinc and calcium were determined through ICP-AES. Additionally, the presence of phytic acid, which inhibits zinc bioavailability, was extracted and quantified using UV-Vis spectroscopy. The results were analyzed in the context of daily product consumption. The findings revealed that certain essential amino acids, such as valine and lysine, were found to be deficient in plant-based meat substitutes compared to animal meat products. It was challenging to meet the recommended daily intake of these amino acids solely through the use of meat substitutes. Regarding zinc bioavailability, the inhibitory effect of calcium on zinc bioavailability was expected to be minimal. The zinc bioavailability of the meat substitutes varied significantly depending on the zinc and phytic acid content of the ingredients. Therefore, ingredients of plant-based meat substitutes should be carefully modulated to reach appropriate zinc bioavailability by selecting and processing plant materials with high zinc and low phytic acid content.

• Advanced Industrial SCIence
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• v.3 no.2
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• pp.8-16
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• 2024

This paper shows the system of drug classification, the goal of this is to foretell the apt drug for the patients based on their demographic and physiological traits. The dataset consists of various attributes like Age, Sex, BP (Blood Pressure), Cholesterol Level, and Na_to_K (Sodium to Potassium ratio), with the objective to determine the kind of drug being given. The models used in this paper are K-Nearest Neighbors (KNN), Logistic Regression and Random Forest. Further to fine-tune hyper parameters using 5-fold cross-validation, GridSearchCV was used and each model was trained and tested on the dataset. To assess the performance of each model both with and without hyper parameter tuning evaluation metrics like accuracy, confusion matrices, and classification reports were used and the accuracy of the models without GridSearchCV was 0.7, 0.875, 0.975 and with GridSearchCV was 0.75, 1.0, 0.975. According to GridSearchCV Logistic Regression is the most suitable model for drug classification among the three-model used followed by the K-Nearest Neighbors. Also, Na_to_K is an essential feature in predicting the outcome.

• Journal of The Korean Association For Science Education
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• v.26 no.3
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• pp.376-384
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• 2006

The purposes of this study were to analyze the frequency and type of volition strategy, according to achievement level, employed by students with high learning motivation, and to identify the role volition strategy plays in keeping students motived to learn science. To accomplish these aims, two groups of students(each containing three members) were selected. Students in the two groups both had the same cognitive level and high learning motivation. However, one group's science achievement was high, and the other was low. Through interviews and class observations, volition strategies students in the two groups used when they encountered hindrances in science learning were compared. Results of the study revealed a relationship between achievement level and volition strategy. Students showed differences in the frequency and types of volition strategies used according to science achievement. It was found that students with higher achievement levels used volition strategies more often to overcome hindrances in science learning than those with lower achievement levels. Furthermore, students with higher achievement levels generally used internal mind control strategies while those with lower achievement levels used environmental control strategies. Lastly, findings found that the types of volition strategies used by lower achievement level students were very limited.

• Journal of The Korean Association For Science Education
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• v.29 no.6
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• pp.626-638
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• 2009

The purpose of this study was to investigate the perception of the scientifically gifted high school students to the research and education (R&E) program. 270 scientifically gifted high school students participating in R&E program were sampled and surveyed according to the R&E' purpose, the process of topic selection, the advantage, and disadvantage of R&E. 4 students among them were interviewed in depth. Students perceived the purposes and advantages of R&E as fostering the scientist' qualifications, providing the research opportunities, and improving the inquiry ability and the disadvantages of R&E as the time consumption in research, the participation as a sideline, and the difficulty of contents. The R&E program was mainly composed of a pre-determined topic, fixed procedures, and expert's settlements in the problem-emerging situation and was not cognitive but technical apprenticeship. In addition, students considered the participation of R&E as a chance of experience about the high techniques and the valuable instruments instead of the improvement on the creative problem-solving ability. The role of mentors in the R&E program is so important that it affects largely on the productive participation and the perceptions of science and scientists.

• Journal of The Korean Association For Science Education
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• v.29 no.6
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• pp.639-652
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• 2009

This projects was carried out under the assumption that an appealing leadership program would lead to students' increased leadership abilities. This leadership program is comprised of 16 materials based on seven factors of leadership for the gifted and talented. More than 46% of the gifted and talented have a positive response to leadership program, and some of these gifted and talented students (14.7%) reacted negatively. According to the result of the T-Test, a survey about leadership of gifted and talented, there are meaningful differences between before and after implementing this leadership program (p<.01). Especially, the leadership quality of the gifted and talented improved effectively in communication skills(p<.01), individualized considerations(p<.01), and interpersonal skills(p<.05). But there aren't statistical differences between the primary school students and the middle school students except leadership total score(p<.05) and communication skills(p<.01). Comprehensively, the primary school students scored slightly higher than did middle school students on the seven factors of leadership. So, we need an effective guide in planning a leadership program for middle school students.

• Journal of The Korean Association For Science Education
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• v.29 no.5
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• pp.531-540
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• 2009

The purpose of this study is to investigate the meaning and process of scientific observation. Hence, this study reviewed and discussed meanings and process of scientific observation described in philosophy, the philosophy of science and science education. Major researches on scientific observation are focused on a characteristic and type of scientific observation behavior. These research can suggest what is the characteristic of observation facts generated by observer. But it cannot show what is the meaning and process of scientific observation, it should be provide to students. According to the result in this study, scientific observation is affected by observer's subjective factors, such as experience, background knowledge, interpretation(not inference) and observation skill. All factor are integrated as an intellectual framework, and it is able to be changed by the observed facts. On the other hand, inference is excluded on scientific observation, but it have constantly affect on intellectual framework through feedback. This study on scientific observation provides a scaffold in various activities of scientific observation to be provided to students.

• Journal of The Korean Association For Science Education
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• v.29 no.5
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• pp.477-491
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• 2009

The purpose of this study is to analyze activities of mentally retarded students studying science within inclusive classes from the aspect of activity sharing to investigate ways of improving their involvement in the tasks. For this study, three mentally retarded students and their peer group in inclusive classes were observed and videotaped for 12 science class sessions about forces and waves. There were many cases in which task involvement of mentally retarded students changed according to three degrees of their activity sharing: well-synchronized, delayed and estranged. When degrees of activity sharing were estranged or delayed, task involvement of the mentally retarded students faded from activeness to passiveness. When the degree of activity sharing was well-synchronized, the mentally retarded students showed interest in learning and were able to participate in science class more actively. Different patterns of activity sharing of mentally retarded students between teacher-centered activities and student-centered activities were observed. In most cases of teacher-centered activities, the monotonous pace could deprive the mentally retarded students of their chance to catch up. As a result, their delayed degrees of activity sharing were faded into estranged degrees. In many cases of student-centered activities, various pacing according to the groups or students could provide mentally retarded students with a chance to catch up, so they could be well-synchronized. In one case of teacher-centered activity, the mentally retarded students were well-synchronized with the teacher's repeated explanations and well-matched illustrations on the blackboard and textbooks. In some cases of student-centered activities, students were well-synchronized with positive relations with and appropriate intervention by other students. In conclusion, various approaches to encourage activity sharing of mentally retarded students with normal ones should be pursued to improve task involvement and academic achievement of mentally retarded students.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.61-72
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• 2007

The relationship between North Pacific chum salmon (Oncorhynchus keta) population and climate variability was investigated in the North Pacific ecosystem. Time-series for the Aleutian Low Pressure, Southern Oscillation, Arctic Oscillation, and Pacific Decadal Oscillation (PDO) indices dating back to 1950 are compared with the chum salmon catch using a cross-correlation function (CCF) and cumulative sum (CuSum) of anomalies. The results of CCF and CuSum analyses indicated that there was a major change in climate during the mid 1970s, and that the chum salmon population responded to this climate event with a time-lag. The PDO and chum salmon returns showed a highly significant correlation with a time-lag of 3 years, while the AOI with a time-lag of $6{\sim}7$ years. The favorable environments for fry chum salmon might cause better growth in the coastal areas, but higher growth rate during the early stage does not seem to be related to the improved return rate of spawning adults. Rather, growth in the Okhotsk Sea or the Bering Sea during immature stages has a significant correlation with return rate, which implies the size-related mortality process. The development of a local climate index is necessary to elucidate the effect of climate variability on the marine ecosystem around the Korean Peninsula.