• KSBB Journal
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• v.23 no.4
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• pp.350-354
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• 2008

Magnetically separable immobilized trypsin was developed and their biocatalytic activity was evaluated for the different immobilization media. The activity, recyclability, pH effect, and stability of immobilized enzymes were evaluated for the different supporting media. The biocatalytic activity of immobilized trypsin was highest with magnetically separable polyaniline (PAMP), and Vm and Km of PAMP were 0.169 mM/min and 0.263 mM respectively. With increasedpH, the biocatalytic activity increased for all supporting materials used. Immobilized enzymes were recycled and recycle activities were over 90% of their original activity after ten times reuse. The operational stabilities of enzymes were greatly improved with enzyme immobilization.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.4
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• pp.129-134
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• 2004

In this study, we investigated the effect of a nitrogen atom on the amorphization of V-Fe alloy through solid-gas reaction during mechanical alloying (MA). MA by planetary ball mill of $V_{70}Fe_{30}$ elemental powders was carried out under the nitrogen gas atmosphere. Amorphization has been observed after 160 hours of ball milling in this case. The DSC spectrum for the mechanically alloyed ($V_{70}Fe$_{30}$)_{0.89}N_{0.11}$ powders exhibits a sharp exothermic peak due to crystallization at about $600^{\circ}C$. Structural transformation from the bcc crystalline to amorphous states was also observed through X-ray and neutron diffractions. We take a full advantage of a negligibly small scattering length of the V atom in the neutron diffraction measurement. During amorphization process the octahedral unit, which is typical of a polyhedron formed in any crystal structures, was preferentially destroyed and transformed into the tetrahedral unit. Futhermore, neutron diffraction measurements revealed that a nitrogen atom is selectively situated at a center of the polyhedron formed by V atoms.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5083-5090
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• 2012

This study was designed to examine the effect of emotional control and interpersonal cognitive problem solving ability on children's interpersonal relationship formative. The subjects were 133 boys and girls who were day care center in G metropolitan city. Data analysed with t-test, ANOVA, Pearson correlation coefficient, regression. The results were as follows. First, there were significant differences in the children's interpersonal relationship formative according to children' sex. There were significant differences in the emotional control and interpersonal cognitive problem solving ability according to their sibling and mother occupation. Second, there were significant correlations between the children's interpersonal relationship formative, emotional control and interpersonal cognitive problem solving ability. Third, the children's interpersonal relationship formative was affected by emotional control and interpersonal cognitive problem solving ability.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.1
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• pp.25-32
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• 2005

In this paper, it is attempted to provide a unified explanation for typical short channel GaAs MESFET’s and SOI-structured Si JFET's behaviors such as: i) drain voltage-induced threshold voltage roll-off, ii) finite output ac resistance beyond the saturation, and iii) weak dependence of the drain saturation current on the channel length. Replacing the conventional GCA with a new assumption that is suggested in order to include the longitudinal field variation, and taking into account the channel current continuity and the field-dependent mobility, we can derive the two-dimensional potential in both depletion region and undepleted conducting channel. Obtained expressions for the threshold voltage and the drain current will be considerably accurate over the entire operating region. Moreover, in comparison with the conventional channel length shortening models, our model seems to be more reasonable in explaining the Early effect.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.12
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• pp.103-112
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• 2005

In this paper, in order to derive the current-voltage characteristics of n-AlGaN/GaN HEMTs with the piezoelectric and spontaneous polarizations, we suggested analytical solutions for the two-dimensional Poisson equation in the AlGaN and GaN regions by taking into account the longitudinal field variation, field-dependent mobility, and the continuity condition of the channel current flowing in the quantum well. Obtained expressions for long and short channel devices would be applicable to the entire operating regions in a unified manner. Simulation results show that the drain saturation current increases and the cutoff voltage decreases as drain voltage increases. Compared with the conventional models, the present model seems to provide more reasonable explanation for the drain-induced threshold voltage roll-off and the channel length modulation effect.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.4559-4565
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• 2015

The purpose of this study is to investigate the relationship between teacher's self-efficacy and teacher's leadership in kindergartens and child care centers. The subjects are 215 teachers employed in kindergartens or child care centers in Chungnam & Daejeon Metropolitan City. Questionnaires, which required self-reporting by teachers, are used to investigate teacher's self-efficacy and teacher's leadership. The data are analyzed by frequency, percent, Pearson's correlation and stepwise regression. The results of this study are as follow. First, teacher's self-efficacy is positively associated with teacher's leadership. Second, teacher's self-efficacy affect teacher's leadership.

• Korean Journal of Adult Nursing
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• v.13 no.3
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• pp.385-396
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• 2001

The purpose of this study is to present an actual example for procedures for developing a PBL package based on philosophical backgrounds derived from Problem-based learning. To perform a systemic study on the operations of an intergrated curricula under multidisciplines, a research team made up of several professors with different academic backgrounds was formed. Among the four situations for the patients with perception-adjustment disorder, especially a procedure for the development of PBL package which can be used in the emergency room situation has been proposed. The little(2000)'s PBL package model has been applied for this study. Tha package includes course objectives, learning objectives, concept map, situation scenario, tutor guide, and evaluation method. It is believed that learning objectives achievement procedures designed as a part of a problem-based learning package development procedures for the nursing of patients with perception-adjustment can be achieved at the same level as the learning objectives for the science of nursing founded by the Korean Nurses Association.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.45-52
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• 2016

The purpose of this study was to investigate the meaning of conflict experience in cooperative learning activities of pre-service early childhood teachers. The subjects were 85 pre-service early childhood teachers in W university. The data were collected through unstructured interviews and journal writings of the participants. The study results were as follow. First, pre-service early childhood teacher's conflict experiences in cooperative activity are team meeting, fair participation and evaluation, and conflict of the personal relations. Second, pre-service early childhood teacher's conflict resolution experiences in cooperative activity are autonomy of the team meeting time, reflective thinking, sentimental support, recognition of others, and solving problems by the time spending together. Third, the meanings of conflict experience in cooperative activity are formation of felt responsibility, self-growth through consideration of others, reciprocity, and recognition of the meaning of cooperation.

• Journal of Powder Materials
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• v.16 no.5
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• pp.316-325
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The experiment results show that the as-prepared Fe amorphous powders less than 90 $\mu$m in size has a fully amorphous phase and its weight fraction was about 73.7%. The as-atomized amorphous Fe powders had a complete spherical shape with very clean surface. Differential scanning calorimetric results of the as-atomized Fe powders less than 90 $\mu$m showed that the glass transition, T$_g$, onset crystallization, T$_x$, and super-cooled liquid range $\Delta$T=T$_x$-T$_g$ were 512, 548 and 36$^{\circ}C$, respectively. Fe amorphous powders were mixed and deformed well with 10 wt.% Cu by using AGO-2 high energy ball mill under 500 rpm.

• Journal of Powder Materials
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• v.16 no.5
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• pp.326-335
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• 2009

Fe based (Fe$_{68.2}$C$_{5.9}$Si$_{3.5}$B$_{6.7}$P$_{9.6}$Cr$_{2.1}$Mo$_{2.0}$Al$_{2.0}$) amorphous powder, which is a composition of iron blast cast slag, were produced by a gas atomization process, and sequently mixed with ductile Cu powder by a mechanical ball milling process. The Fe-based amorphous powders and the Fe-Cu composite powders were compacted by a spark plasma sintering (SPS) process. Densification of the Fe amorphous-Cu composited powders by spark plasma sintering of was occurred through a plastic deformation of the each amorphous powder and Cu phase. The SPS samples milled by AGO-2 under 500 rpm had the best homogeneity of Cu phase and showed the smallest Cu pool size. Micro-Vickers hardness of the as-SPSed specimens was changed with the milling processes.