• Korean Journal of Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.17-22
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• 1977

In the present paper, the effect of sodium sulfite treatment on tile inhibition of browning reactions occurring in the storage of dried oyster was tested and the supplementary effect of antioxidantsaddedwasalsomentioned. Dried oysters treated with sodium sulfite solutions as described in the previous paper(Lee and Choi, 1977) were stored in the bottles with silica gel bags at room temperature with or without the application of antioxidants. The ethanol solution of an antioxidant mixture(BHA, BHT, plus, synergists) was sprayed on the surface of cooked oyster before drying. The density of brown pigment was determined spectrophotometrically by measuring the absorbance at 420 and 440 nm of both fractions of pigment extract, namely chloroform-methanol and water soluble fractions, which represent the brown color developed by fat oxidation and Maillard reactions respectively. TBA value was also measured for the oxidative rancidity in oysters during the storage. It appeared from the results that the 0.5 M sodium sulfite-60minute treated samples showed better effect after 150 day storage at room temperature. Controlling tile pH of treating solutions, did not reveal so much different in inhibitory effect in the aspect of color but a more reduction of tyrosine and reducing sugar was resulted with acidic solution than with alkaline solution. The development of brown color in dried oyster seemed to be leaded rather by the oxidative rancidity of lipids than sugar-amino reactions particularly in a long-term storage since the browning of chloroform-methanol fraction progressed more rapidly than of water. soluble fraction. The application of antioxidant, therefore, could largely retard the browning of the product as appeared in the results that sodium sulfite treated oyster with addition of antioxidant kept the best color during the storage.

• Korean Journal of Community Nutrition
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• v.11 no.4
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• pp.469-478
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• 2006

In order to investigate the adolescent's beverage drinking pattern and its related ecological factors, a questionnaire survey was conducted with the subjects of 920 middle and high-school students,450 boys and 470 girls, residing in 4 cities of the Chungnam area. Of the subjects 65% liked, or liked very much, beverages and only 3.7% did not like beverages. They drank beverages 4.3 $\pm$ 4.0 times a week on average, but 10.4% of them drank beverages more than twice a day. Male students drank more frequently than the females. The intake frequency of carbonated drinks was 1.7 $\pm$ 2.3 a week which was about 40% of the total beverages. However, more students drank mainly ion beverages (33.6%) than carbonated drinks (28.7%). As the students took more balanced food and ate more regularly, their beverage drinking frequency decreased and those taking carbonated drinks also tended to decrease. The more frequent the students took fast food, the more frequent they drank carbonated beverages. The drinking frequencies for beverages or carbonated beverages were also less in students eating cooked rice with sidedishes as breakfast than in students eating others. The drinking frequency for carbonated drinks showed significant correlations with the students' activities such as the time spent using computers and watching TV got longer, the drinking frequency for soft drinks was also higher. When nutritional knowledge was higher, drinking frequency for carbonated drinks got lower. In conclusion, to make the adolescents improve their attitudes toward drinking beverages and to prevent excessive drinking of carbonated drinks, they should be educated not only on the nutritional knowledge and the proper intake of beverages, but also on good dietary habits including balance, regularity, and types of meals. Proper snacking and fast food consumption also should be taught. Since ion beverages were taken more frequently than carbonated drinks among adolescents, further study is recommended on the impact of excessive intake of ion beverages.

• Journal of the Korean Vacuum Society
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• v.19 no.5
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• pp.360-364
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• 2010

Most research groups used two analysis methods (spectroscopy and nanotribology) to measure the mechanical properties of nano-materials: NMR (Nuclear Magnetic Resonance), IR (Infrared Spectroscopy), Raman Spectroscopy as the spectroscopy method and AFM (Atomic Force MicroScope), EFM (Electrostatic Force Microscope), KFM (Kelvin Force Microscope), Nanoindenter as the nanotribological one. Among these, the nano-indentation technique particularly has been recognized as a powerful method to measure the elastic modulus and the hardness. However, this technique are prone to considerable measurement errors with pressure conditions during measurement. In this paper, we measured the change of elastic modulus and hardness of an Al single crystal with the change of load, hold, and unload time, respectively. We found that elastic modulus and hardness significantly depend on load, hold, and unload time, etc. As the indent time was shortened, the elastic modulus value decreased while the hardness value increased. In addition, we found that elastic modulus value was more sensitive to indent load, hold, and unload time than the hardness value. We speculate that measurement errors of the elastic modulus and the hardness originate from the residual stress during indenting test. From our results, the elastic modulus was more susceptible to the residual stress than the hardness. Thus, we find that the residual stress should be controlled for the minimum measurement errors during the indenting test.

• Journal of The Korean Association For Science Education
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• v.20 no.4
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• pp.572-581
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• 2000

Teachers' perceptions about curricular objectives are very important to achieve given educational objectives. This study examined teachers' perceptions about priority and hinderance of science objectives. The national science curriculum stated four areas of objectives: inquiry, knowledge, attitude, and STS. A total of 76 elementary and 217 secondary teachers were responded to questionnaire developed for this study. Non-parametric statistics, such as Friedman test, Kruskal-Wallis test, and chi-square test were used by using SPSS/PC program. Teachers in general ranked the inquiry first among the four areas at their perception on the national curriculum, on themselves, and on their instructions. Elementary teachers ranked inquiry higher than secondary science teachers, while secondary science teachers ranked knowledge higher than elementary teachers. As factors hindering teachers from achiving the objectives, elementary teachers pointed out overcrowded classroom and secondary science teachers pointed out college and university entrance examination respectively.

• Journal of The Korean Association For Science Education
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• v.36 no.3
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• pp.423-434
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• 2016

The purpose of this study is to investigate preservice earth science teachers' mental models through applications of Coriolis force experiment apparatus. After the root of preconception was examined by face to face interviews based on the questionnaire, five preservice earth science teachers were finally selected for this study. The mental models about concept of Coriolis force was classified into naive mental model, static unstable mental model, dynamic unstable mental model, and scientific mental model through the result of individual interviews and their drawings. According to the mental model analysis about Coriolis' force conception, students C and M showed naive mental model about concept of Coriolis force before experiment. After the experiment, student M's model changed to static unstable mental model. Student C's model improved to dynamic unstable mental model. In adiition, students D and O's model improved from static unstable mental model to dynamic unstable mental model. In the case of student B, the dynamic unstable mental model was maintained after the experiment, however, student B's preconception changed to scientific concept. It turned out that a change occurred from low mental model level to integrated mental model after the application of the developed Coriolis' force experiment apparatus. According to the results, national curriculum is similar to static unstable mental model and the result of developed Coriolis' force experiment apparatus is similar to dynamic unstable mental model. It is suggested that it become the theoretical foundation to develop more comfortable and advanced Coriolis force experiment apparatus by improving the experiment apparatus.

• Journal of the Korean Society of Food Culture
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• v.28 no.4
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• pp.415-423
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• 2013

The purpose of this study was to estimate the consumption prevalence of vitamin and mineral supplements as health functional foods (VM-HFF) and to examine the factors associated with VM-HFF consumption behaviors in adolescents. A total of 1,407 adolescents attending middle or high schools from various cities and rural communities in Korea participated in this study. The prevalence of VM-HFF consumption was 41.7%, with boys showing a higher consumption than girls (p<0.01). VM-HFF consumption was higher in families with higher socioeconomic status and for families with parents that exhibited higher concerns about their child's health, growth, and nutritional intake (p<0.001). Most consumers of VM-HFF consumed HFFs 'when healthy' (50.1%), and acquired nutritional information from 'their families & relatives' (50.9%). Most consumers responded that VM-HFF was 'a little effective' (54.3%), followed by 'no obvious effects' (37.1%), and 'very effective' (7.4%). The effectiveness of consuming VM-HFF was mainly for 'fatigue recovery' (39.0%) and 'health improvement' (28.2%). Most consumers purchased HFFs at 'pharmacies & oriental medicine clinics' (53.8%) and at 'health functional food stores' (18.8%). Most consumers 'occasionally' (51.1%) or 'seldom' (27.3%) checked nutrition facts when purchasing, with 58.9% of consumers understanding the nutritional label for 'the most part', but only 8.7% of them understanding it 'very well'. Among the VM-HFF, consumers preferred calcium- and vitamin C-supplements. Consumers' mini-dietary assessment scores were higher than those of non-consumers. The results above showed that VM-HFF consumption was widely spread among adolescents, but few consumers checked and understood the nutrition label when they purchased VM-HFF, and were highly dependent on the advice and information from non-professional nutritionists, such as families & relatives. Therefore, it is necessary to educate adolescents to help them read nutrition labels and select the proper VM-HFF.

• Journal of the Korean association of regional geographers
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• v.15 no.1
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• pp.115-137
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• 2009

Recently, industrial locations have faced changing trends under the influence of emerging industries as well as advanced new technologies. So the purpose of this study is to analyze the spatial distribution and locational factors of biotechnology industry formed around the Seoul Metropolitan area and Daejeon city, both of which are centers of Korean biotechnology industry, and is also to identifytheir locational characteristics. Major results of this study can be outlined as follows: First, from the mid 1990' s to 2000, Korean biotechnology industry has rapidly developed owing to central and local governmental support policies and systems as well as changes in domestic economic environment due to Korean financial crisis. Secondly, it was found that spatial distribution of Korean biotechnology industry converged on the Seoul Metropolitan area till 1990, but shifted from there to Daejeon and Chungcheong area from 1990 to 2000. Particularly after 2000, positive local governmental efforts to attract biotechnology players have driven the spatial distribution of biotechnology industry to shift from Seoul Metropolitan area and Daejeon or adjacent area gradually to other profitable locations. In terms of locational factors, it was found that the locations of Korean biotechnology industry converged primarily on university or college campus and biotechnology venture center, particularly on locations adjacent to superhighway or expressway. Locational factors varied depending on region, industrial type and business growth phase. Therefore, it is advisable that our central and local government should make and implement practical and useful policies in favor of biotechnology business depending on region, industrial type, business growth phase, rather than depending on uniform locational policies.

• Korean Journal of Plant Resources
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• v.28 no.2
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• pp.158-167
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• 2015

We selected 8 plants among 11 Jeju native plants to search useful natural anti-oxidants by determining the amount of total polyphenols and the various anti-oxidative effects. Ethyl acetate extracts of Castanopsis sieboldii (Makino) Hatus. and butanol extracts of Oenothera laciniata Hill showed strong DPPH free radical scavenging effect. The IC₅₀ value of each solvent extract was 1.6 ㎍/㎖ and 2.4 ㎍/㎖, respectively. The ethyl acetate fraction of Castanea crenata Siebold & Zucc exhibited strong inhibition against nitric oxide production. For the inhibition of xanthine oxidase, the ethyl acetate extracts of Castanea crenata Siebold & Zucc showed strong inhibition activity with 16 ㎍/㎖ of its IC₅₀. The ethyl acetate extracts from Castanopsis sieboldii (Makino) Hatus showed strong superoxide scavenging effect with 7 ㎍/㎖ of its IC₅₀. The hydroxyl radical scavenging activity of butanol extract of Castanopsis sieboldii (Makino) Hatus was 76%. Therefore, with more researches on purification and identification of active compounds, plants studied are expected to be natural sources for the functional food/cosmeceuticals with anti-oxidative properties.

• (The) Korean Journal of Educational Psychology
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• v.32 no.3
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• pp.549-569
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• 2018

The purpose of this study is to examine the relationship between peer rejection and victimization among schoolchildren and to test whether conflict norms in the classroom moderated this relationship. The analysis used the third year data derived from ClassNet research (Park, et al., 2017) supported by the National Research Foundation of Korea. The sample comprised fourth-grade through sixth-grade students in 52 classrooms of 7 elementary schools in South Korea (N = 1194). A series of multi-level analyses were performed to fulfill the study's purpose using variables obtained by peer nomination, such as social rejection, victimization, bullying perpetration, and teacher-student conflict. The results found that boys experienced more victimization than girls and peer rejection significantly increased victimization. Furthermore, conflict norms in the classroom moderated the relationship between peer rejection and victimization. Peer rejection significantly increased the extent of victimization in classrooms with relatively high levels of conflict norms. The study concludes with a discussion on the significance of conflict norms and the educational implications of the results with a focus on ways that teachers can facilitate healthier classroom environments.

• Journal of the Korean Society of Earth Science Education
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• v.15 no.1
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• pp.76-90
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• 2022

In this study, after applying the argument structure class design program for 20 preservice earth science teachers, we conducted individual in-depth interviews, analyzed the data, and derived a scientific argumentation PCK development model. The scientific argumentation PCK development model consists of three dimensions: Scientific argumentation PCK, PCK ecosystem, and reflective practice. Scientific argumentation PCK is demonstrated in the process of designing or executing classes using argumentation structures as an instructional reasoning tool. PCK ecosystem, consisting of the existing conventional PCK components, is a dimension surrounding the scientific argumentation PCK, and these two dimensions develop by interacting with each other. Reflective practice regulates each dimension and develops it in various ways by mediating the two dimensions of the scientific argumentation PCK and the PCK ecosystem. The conclusions drawn based on the results are as follows: First, preservice science teachers can demonstrate scientific argumentation PCK in the process of design and implementation of lessons using argumentation structures as a pedagogical reasoning tool. Second, it is necessary to develop the PCK for pedagogical reasoning tools such as scientific argumentation PCK in advance for the development of science teachers' PCK, since the scientific argumentation PCK can develop various components of the PCK ecosystem. Finally, it is necessary to use scientific argumentation PCK to support the preservice teacher's reflective practice, seeing that the scientific argumentation PCK promotes the development of PCK ecosystem components by inducing reflective practice.