• Hwankyungkyoyuk
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• v.17 no.1
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• pp.101-111
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• 2004

The selection rates of Environmental subject have been increasing since the environmental subject was made. Although the quantitative growth, environmental subject is not acknowledged yet in many schools in Korea. Most of environmental teachers teach two subjects; main subject on their own major and environmental subject. In this respect, this qualitative case study aims to show the influence of teachers' charge on environmental class or environmental subject. In the case study, Teacher 'A' takes charge one subject; Environmet, and teacher 'B' takes charge two subjects; Social Study and Environment. Teacher 'A' took some current issues such as SARS(Severe Acute Respiratory Syndrome) and Saemangum project, and uses various instructional methods and instruments. On the other hand, teacher 'B' might not choose the current issues, or usually gives up various instructional methods and instruments because of lack of time. Although they have those differences on the instruction, the teachers 'A' and 'B' both agreed to the importance of Environmental Education as well as they did their best to prepare for class on environmental subject. As a result, all these outcomes show teachers need to be responsible for single subject on environment as teachers' interests seriously affect to environmental subject and class.

• Journal of the Korean Electrochemical Society
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• v.15 no.2
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• pp.109-114
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• 2012

The cathode catalyst layer in polymer electrolyte membrane fuel cells (PEMFCs) was fabricated with anodic aluminum oxide (AAO) template and its structure was characterized with scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The SEM analysis showed that the catalyst layer was fabricated the Pt nanowire with uniform shape and size. The BET analysis showed that the volume of pores in range of 20-100 nm was enhanced by AAO template. The electrochemical properties with the membrane electrode assembly (MEA) were evaluated by current-voltage polarization measurements and electrochemical impedance spectroscopy. The results showed that the MEA with AAO template reduced the mass transfer resistance and improved the cell performance by approximately 25% through controlling the structure of catalyst layer.

• Journal of Electrochemical Science and Technology
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• v.1 no.1
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• pp.19-24
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• 2010

Alloying degree is an important structural factor of PtRu catalysts for direct methanol fuel cells (DMFC). In this work, carbon supported PtRu catalysts were synthesized by reduction method using anhydrous ethanol as a solvent and $NaBH_4$ as a reducing agent. Using anhydrous ethanol as a solvent resulted in high alloying degree and good dispersion. The morphological structure and crystallanity of synthesized catalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HR-TEM). CO stripping and methanol oxidation reaction were measured. Due to high alloying degree catalyst prepared in anhydrous ethanol, exhibited low onset potential for methanol oxidation and negative peak shift of CO oxidation than commercial sample. Consequently, samples, applying ethanol as a solvent, exhibited not only enhanced CO oxidation, but also increased methanol oxidation reaction (MOR) activity compared with commercial PtRu/C (40 wt%, E-tek) and 40 wt% PtRu/C prepared in water solution.

• Journal of The Korean Astronomical Society
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• v.47 no.1
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• pp.1-13
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• 2014

We analyze the dependence of disk morphology (arm class, Hubble type, bar type) of nearby spiral galaxies on the galaxy environment by using local background density (${\Sigma}_n$), projected distance ($r_p$), and tidal index (T I) as measures of the environment. There is a strong dependence of arm class and Hubble type on the galaxy environment, while the bar type exhibits a weak dependence with a high frequency of SB galaxies in high density regions. Grand design fractions and early-type fractions increase with increasing ${\Sigma}_n$, $1/r_p$, and T I, while fractions of flocculent spirals and late-type spirals decrease. Multiple-arm and intermediate-type spirals exhibit nearly constant fractions with weak trends similar to grand design and early-type spirals. While bar types show only a marginal dependence on ${\Sigma}_n$, they show a fairly clear dependence on $r_p$ with a high frequency of SB galaxies at small $r_p$. The arm class also exhibits a stronger correlation with $r_p$ than ${\Sigma}_n$ and T I, whereas the Hubble type exhibits similar correlations with ${\Sigma}_n$ and $r_p$. This suggests that the arm class is mostly affected by the nearest neighbor while the Hubble type is affected by the local densities contributed by neighboring galaxies as well as the nearest neighbor.

• Journal of Electrochemical Science and Technology
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• v.2 no.4
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• pp.204-210
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• 2011

Thin film electrodes have been intensively studied for active materials and current collectors to enhance the electrochemical performance. Here, porous structures of nickel-based oxide films, consisting of nickel oxide and copper (II) oxide, which was derived from the copper substrate during the annealing process, were deposited on metallic copper foils. The half-cell tests revealed excellent capacity retention after $80^{th}$ charge/discharge cycles. Some films showed an excess of the theoretical capacity of nickel oxides, which mainly originate from partially oxidized copper substrates during annealing. These results exhibit that both a preparation method of an active materials and partially oxidized current collectors could be important roles to apply thin film electrodes.

• Journal of the Korean Institute of Educational Facilities
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• v.20 no.6
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• pp.21-30
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• 2013

This study aimed to identify elementary school teachers' perceptions of various aspects of physical environments of a classroom. For the purpose, a survey questionnaire was administered to 982 classroom teachers(female 82.2%) working at 67 elementary schools(Seoul 55%) located in Seoul and Busan. According to the analyses of the survey data, 50.8% of the respondent teachers suggested 20-25 as an optimum class size. Also, 57% of the teachers were positive about the current size of a classroom($67.5m^2$), but evaluations of a classroom size were divided between the teachers who had more and less than 30 students in class. Furthermore, three factors, labelled as 'uniqueness', 'residential stability' and 'visually pleasing', were extracted from a factor analysis of the Semantic Differential Scale consisting of 24 adjectives evaluating a classroom environment. Teachers from Busan tended to rate higher in the uniqueness domain while female teachers scored higher in the domain of residential stability, respectively, compared to their counterparts. Overall, the teachers perceived their classrooms having no particular characteristics, but rated highly in terms of stability. In addition, it was found out that the teachers' requests for the improvement of a classroom environment were not so much as the increased size of a classroom as a reduced class size as well as educational facilities that are corresponding to a variety of instructional methods. In summary, this study confirmed that elementary school teachers' perceptions of a classroom environment varied according to such factors as sex, teaching career, grade of their concerned class, and class size.

• Journal of the Korean Institute of Rural Architecture
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• v.13 no.4
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• pp.25-34
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• 2011

On former days, school has realized as "where teach", but development of a technology and change of paradigm are changing school as "where study". This is meaning that student is more important and be considered than others when make school environment. Due to continuous investment of national level in several decades, in our elementary school's facilities and environment, when compare with advanced nations that we know that have come to the fairly high level. But, it is not really certainly in middle school and high school. Than the reason is, 'College entrance examination' is prior than other certain values in occasion of high school especially, and we ask a question in return whether have persuaded ourselves that school facilities and environment may change later. It is hard to find more important thing than the proposition in fact on present society. However, it is that society and facilities that can correspond to fast change of paradigm, change of curriculum, learner's change and environment have to be changed in middle school and high school now. Departmentalized Class System that applies in national middle and high school now can become an opportunity that can improve school facilities and environment of middle and high school. In such background, I studied space satisfaction and student's moving route and pattern characteristic of Departmentalized Class System high school in Chungcheongbuk-do area. And this study aims at supply the data about efficient Departmentalized Class System School's facilities plan and space use which can meet on request of students.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.613-619
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• 2011

Colloidal silver nanoparticles (AgNPs) have been commercialized as the typically stabilized form via the addition of a variety of surfactants or polymers. Herein, to examine the effects of stabilizing AgNPs in suspension, we modified the surface of bare AgNPs with four type of surfactants (NaDDBS, SDS, TW80, CTAB) and polymers (PVP, PAA, PAH, CMC). The modified AgNPs was applied to compare suspension stability and nanotoxicity test using Escherichia coli (E. coli) as a model organism. Modification of AgNPs surface using chemical stabilizer may be not related with molecular weight, but chemical structure such as ionic state and functional group of stabilizer. In this study, it is noteworthy that AgNPs modified with a cationic stabilizer (CTAB, PAH) were importantly toxic to E. coli, rather than anionic stabilizers (NaDDBS, SDS). Comparing similar anionic stabilizer, i.e., NaDDBS and SDS, the result showed that lipophilicity of chemical structure can affect on E. coli, because NaDDBS, which contains a lipophilic benzene ring, accelerated the cytotoxicity of AgNPs. Interestingly, none of the stabilizers tested, including biocompatible nonionic stabilizers (i.e., TW80 and cellulose) caused a reduction in AgNP toxicity. This showed that toxicity of AgNPs cannot be reduced using stabilizers.

• Journal of the Korean Society of Earth Science Education
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• v.8 no.3
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• pp.346-354
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• 2015

The purpose of this study was to be a help with designing science curriculum and developing science programs for the science gifted students by comparing their preferences about science class forms and class environments between science gifted students and normal students. For this study, 2 classes of science gifted students and 5 classes of normal students in 4th, 5th grade joined in this survey and their preferences about science class forms and class environments were checked using questionnaire. As a result, the following findings were obtained. First, in the area of class form, from comparing their preferences about teaching content domain, science gifted students showed meaningful higher preferences in all factors such as clarification, structuralization, thinking of high level and diversification. In comparing their preferences about teaching process domain, science gifted students also showed meaningful higher preferences in all factors such as diversification and self directed learning. Second, in the area of class environment, from comparing their preferences about classroom domain, science gifted students showed meaningful higher preferences in all factors such as teacher's support and rule and organization. In comparing their preferences about mentality domain, science gifted students also showed meaningful higher preferences in all factors such as influence of friends and parents. Third, in science gifted students, from comparing their preferences by gender about science class forms and class environments, female students showed meaningful higher preferences in factors of clarification. And in other factors females showed similar preference tendency with male students. In normal students' comparing, female students showed meaningful higher preferences in factors of teacher's support. And male students showed meaningful higher preferences in factors of high level thinking and influence of friend and influence of parents.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.2
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• pp.215-224
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• 1997

This paper addresses the vertical class fragmentation in distributed object-oriented databases. In the proposed vertical fragmentation, after producing the attribute fragment by partitioning attributes, then the method fragment is produced by gathering methods referring the attribute in each fragment. For partitioning attributes, we define query access matrix(QAM) and method access matrix(MAM) to express attributes that method refers, and extend QAM, MAM and attribute usage matrix(AUM) to universal class environment for representing relationship among other classes through class hierarchy and class composite hierarchy.