• 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.

• Journal of Korean Home Economics Education Association
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• v.35 no.2
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• pp.111-132
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• 2023

The objective of this research is to conceptualize care competences for adolescents and to develop a valid measurement tool based on this conceptualization. The primary aim is to establish a solid foundation for effective communication in teaching care competences within the domain of home economics education. To achieve this, a comprehensive review of relevant literature and previous studies was conducted, and consultations with experts were undertaken to assess content and criterion-related validity. Furthermore, exploratory and confirmatory factor analyses were performed. The findings from these analyses resulted in a set of 34 items, which were categorized into five distinctive factors representing care competences in adolescents. These factors encompassed four items of care thinking, seven items of care emotion, six items of care behavior, seven items of self-care and ten items of community-care. Additionally, a reliability analysis was performed on the model, confirming the stability and consistency of the five factor structure and the 34 item scale, which assess care competences in adolescents.

• Journal of Industrial Convergence
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• v.21 no.7
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• pp.51-63
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• 2023

This study aimed to verify the effects of a 4-week program of ankle-strengthening exercise and toe-taping walk exercise on the basic lower body strength and walking to examine the benefits of the two exercises. The subjects involved 30 women in their 20s enrolled in university A. The subjects were equally divided into three groups - ankle-strengthening exercise group, toe-taping walk exercise group, and control group. The subjects were instructed to massage and do ankle-strengthening exercises using a towel, massage ball, and CRT, for 60 minutes, 3 times a week. They also taped their hallux valgus using a kinesiology tape and walked for 20 minutes with white tape applied. To sum up, the 4-week ankle-strengthening exercise and toe-taping walk exercise were identified to have a partial statistical significance on the basic lower body strength (muscular strength, power, and balance) and walking (length of gait line, plantar pressure, and COP) of women in their 20s. Therefore, the study confirmed the effects of ankle-strengthening exercises and toe-taping walk exercise on the lower body exercise function, and it is considered that further studies should be conducted on more various effects of the exercises by subdividing them into different pain locations and orthomechanic findings.