• Title/Summary/Keyword: Theoretical chemistry

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Degradation of Sulfonamide Antibiotic Substances by Ozonation: An Experimental and Computational Approach (설폰아미드계 항생물질의 오존산화분해에 대한 계산화학적 해석 및 실험적 검증)

  • Won, Jung Sik;Lim, Dong Hee;Seo, Gyu Tae
    • Journal of Korean Society of Environmental Engineers
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    • v.36 no.6
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    • pp.442-450
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    • 2014
  • Concern has grown over a presence of micropollutants in natural water since sulfonamide antibiotic substances such as sulfamethazine, sulfamethoxazole, sulfathiazole have been frequently detected in Nakdong River, Korea. The current work investigates the degradation of the three sulfonamide substances by using quantum chemistry calculations of density functional theory (DFT) and experimental measurement techniques of Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectrophotometer (UV-VIS). DFT calculations demonstrate that the lowest energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbitals (LUMO) lies in sulfanilamide functional group of sulfonamide, implying that the sulfanilamide functional group would be the most active site for ozone oxidation. Also, UV-VIS spectra and FT-IR analysis reveal that 260 nm band originated from sulfanilamide group was absent after ozone oxidation, indicating that a functional group of amine (N-H) was removed from sulfanilamide. Both theoretical and experimental observations agree well with each other, demonstrating the DFT calculation tool can be an alternative tool for the prediction of chemical reactions in purification treatment processes.

Application of Response Surface Methodology for the Optimization of Process in Food Technology (반응표면분석법을 이용한 식품제조프로세스의 최적화)

  • Sim, Chol-Ho
    • Food Engineering Progress
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    • v.15 no.2
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    • pp.97-115
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    • 2011
  • A review about the application of response surface methodology in the optimization of food technology is presented. The theoretical principles of response surface methodology and steps for its application are described. The response surface methodologies : three-level full factorial, central composite, Box-Behnken, and Doehlert designs are compared in terms of characteristics and efficiency. Furthermore, recent references of their uses in food technology are presented. A comparison between the response surface designs (three-level full factorial, central composite, Box-Behnken and Doehlert design) has demonstrated that the Box-Behnken and Doehlert designs are slightly more efficient than the central composite design but much more efficient than the three-level full factorial designs.

The Effect of The Types of Manufacturing Factories on Transferred Essence and Consumers' Perceived Value: Moderating Safety Product Betrayal (제조공장 유형이 본질 전이와 소비자의 가치 인식에 미치는 영향: 안전제품 배신을 중심으로)

  • Jeong, Heonbae;Lee, Yongju
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.11 no.5
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    • pp.117-128
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    • 2016
  • In order to extend FOO, this research has the object to demonstrate existing the difference of transferred essence and value between the types of factories(Original factory vs Extended factory). A safety product should save consumers from possible harm or risk, but it sometimes gives directly some damage to consumers. For example, like the issue of a germicide problem in 2016, a germicide killed consumers because of harmful chemistry even it should kept their health. This situation refer to 'Safety product betrayal', we expected that safety product betrayal presence/absence conditions moderate the relationship between types of factories, transferred essence and value. We selected a car air-bag as a safety product for study and implemented one study with total 213 participants. As a result, the participants evaluated the value of an air-bag manufactured throughout an original factory higher than the value of an air-bag manufactured throughout an extended factory. Futhermore, they evaluated the transferred brand essence of an original factory's air-bag higher than an extended factory's. However, in the safety product betrayal presence condition, the difference of value and transferred essence between an original factory and an extend factory was disappeared. Indeed, once consumers experienced or saw safety product betrayal, they avoided to buy or use safety products. Therefore, consumers evaluated the value and transferred essence of betrayed safety products is low without the types of manufacturing factories. From the past to now, there was no paper about the relationship between the types of manufacturing factories(Orignal factory vs Extended factory) and safety product betrayal in Korea. Therefore, this research on FOO and safety product betrayal can give new theoretical and operational contribution. In the conclusion, we discussed the contribution of the study results and proposed the limitation and future study.

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Three Teaching-Learning Plans for Integrated Science Teaching of 'Energy' Applying Knowledge-, Social Problem-, and Individual Interest-Centered Approaches (지식내용, 사회문제, 개인흥미 중심의 통합과학교육 접근법을 적용한 '에너지' 주제의 교수.학습 방안 개발(II))

  • Lee, Mi-Hye;Son, Yeon-A;Young, Donald B.;Choi, Don-Hyung
    • Journal of The Korean Association For Science Education
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    • v.21 no.2
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    • pp.357-384
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    • 2001
  • In this paper, we described practical teaching-learning plans based on three different theoretical approaches to Integrated Science Education (ISE): a knowledge centered ISE, a social problem centered ISE, and an individual interest centered ISE. We believe that science teachers can understand integrated science education through this paper and they are able to apply simultaneously our integrated science teaching materials to their real instruction in classroom. For this we developed integrated science teaching-learning plans for the topic of energy which has a integrated feature strongly among integrated science subject contents. These modules were based upon the teaching strategies of 'Energy' following each integrated directions organized in the previous paper (Three Strategies for Integrated Science Teaching of "Energy" Applying Knowledge, Social Problem, and Individual Interest Centered Approaches) and we applied instruction models fitting each features of integrated directions to the teaching strategies of 'Energy'. There is a concrete describing on the above three integrated science teaching-learning plans as follows. 1. For the knowledge centered integration, we selected the topic, 'Journey of Energy' and we tried to integrate the knowledge of physics, chemistry, biology, and earth science applying the instruction model of 'Free Discovery Learning' which is emphasized on concepts and inquiry. 2. For the social problem centered integration, we selected the topic, 'Future of Energy' to resolve the science-related social problems and we applied the instruction model of 'Project Learning' which is emphasized on learner's cognitive process to the topic. 3. For the individual interest centered integration, we selected the topic, 'Transformation of Energy' for the integration of science and individual interest and we applied the instruction model of 'Project Learning' centering learner's interest and concern. Based upon the above direction, we developed the integrated science teaching-learning plans as following steps. First, we organized 'Integrated Teaching-Learning Contents' according to the topics. Second, based upon the above organization, we designed 'Instructional procedures' to integrate within the topics. Third, in accordance with the above 'Instructional Procedures', we created 'Instructional Coaching Plan' that can be applied in the practical world of real classrooms. These plans can be used as models for the further development of integrated science instruction for teacher preparation, textbook development, and classroom learning.

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