• Korean Journal of Optics and Photonics
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• v.16 no.4
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• pp.297-303
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• 2005

We present the double resonance optical pumping(DROP) spectra according to the laser power, the polarization combination of lasers, and the alignment of lasers in the transition $5P_{3/2}-4D_{5/2}\;and\;5P_{3/2}-4D_{5/2}$ of $^{87}Rb.$ We observed obviously changing DROP spectrum according to the laser power in the transition $5P_{3/2}-4D_{5/2}$ involved the cycling transition. The laser power effects are attributed to the low optical-pumping-effect in the cycling transition. We observed changing DROP spectrum depending on the polarizations of the lasers. The laser polarization effects are attributed to the changing transition probability according to the polarizations of lasers. We compared the co-propagation with the counter-propagation and the spectral linewidths were 12.2 MHz and 6.9 MHz, respectively.

• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.1-6
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• 2005

We have studied the polarization effects and the coupling intensity effects of electromagnetically induced transparency(EIT) in the 5S$_{1}$2-/5P$_{3}$2-/5D$_{5}$2/ ladder system of Rb. We obtained the EIT spectrum with the hyperfine structure of 5D$_{5}$2/ transitions and the minimal width of the measured EIT spectrum was 6.5 MHz. We observed the change of the relative magnitudes of the hyperfine structure of EIT according to not only the polarizations of lasers but also the intensity of the coupling laser. The cause of the coupling intensity effects is that the EIT signal nonlinearly increases to the coupling intensity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.594-597
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• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of 0.2Pb(Mg1/3Nb2/3)O3-0.38PbZrO3-0.42PbTiO3 followed by lamination and burnout & co-firing processes. The actuators of 10 10 0.62 nm3 in size were formed in a way that 60 200 m thick ceramics were stacked alternatively with 5 m thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of 90o/180o domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Structural Engineering and Mechanics
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• v.82 no.2
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• pp.133-149
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• 2022

This study investigates the resistance of sustainable ultra-high performance concrete (UHPC) on steel reinforcement corrosion. For enhancing the sustainability of UHPC, concrete mixes were prepared with ordinary Portland cement main binder, and mixes with moderate to high percentages of blast furnace cement (CEM III), fly ash (FA), and slag cement as partial replacements of the full quantity of the used cement. Linear polarization resistance technique was employed to estimate the electrochemical behavior of the concrete specimens. Results showed that the compressive strength and the resistance of steel to corrosion in marine environments can be enhanced by improving the sustainability of UHPC through incorporation of CEM III, FA, and slag cement. FA replacement of up to 50% with the addition of 15% SF content produced better compressive strength and steel corrosion resistance than slag cement whether with the use of ordinary Portland cement or blast furnace cement as the main binder.

• Journal of Christian Education in Korea
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• v.77
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• pp.7-27
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• 2024

This study addresses the crucial role of Christian Religious Education (CRE) amidst civic polarization, moral disimagination, and learned helplessness. It begins her personal background as a 1.5-generation Vietnamese American and her academic engagement in immigrant faith and the challenges of teaching faith in violent contexts. The work underscores the public dimension and impact of religious education, highlighting its potential for fostering critical capacities for public engagement. However, that study observes a prevalent disconnection between congregational culture and the aim of public engagement, leading to a form of learned helplessness among students and communities. The researcher draws on Paulo Freire's concepts of "critical hope" and the need for a curriculum that transcends mere content delivery to foster transformative engagement with societal issues. The document critiques the disimigination machine that undermines critical thinking and collective resistance, as articulated by Henry Giroux, and explores the concepts of "learned helplessness" as a barrier to environmental and social activism. The researcher advocates for a theopoetic and theopolitical approach to education that nurtures hope and practical engagement with the world's injustice. She emphasizes small acts of theopoetic and theopolitical hope as transformative practices, using an example from Ferguson, Missouri, to illustrate how public liturgy and protest can mediate hope and justice. The document concludes with a call for a life-long, life-wide, and life-deep curriculum of enchantment towards responsible participation in societal repair, rooted in Christian hope.

• Korean Journal of Human Ecology
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• v.20 no.6
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• pp.1199-1212
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• 2011

The purpose of this study is to examine how the mother's educational aspirations and household's characteristics have an effect on the likelihood of private educational expenditures and the amount of private educational expenditures. Factor analysis, probit and tobit analyses were used. The main findings can be summarized as the following: The mother's educational aspirations for intrinsic values is higher than for extrinsic values. The mother's educational aspirations for extrinsic values, household's assets, and residing in Seoul rather than residing in Incheon had significant positive effects on the likelihood of private educational expenditures. However, the child's birth order had a significant negative effect on the likelihood of private educational expenditures. The mother's educational aspirations for extrinsic values, the mother's education level, household's income, household's assets, and residing in Seoul rather than residing in Incheon had significant positive effects on the amount of private educational expenditures. However, the child's birth order had a significant negative effect on the amount of private educational expenditures. Findings from this study offer several implications. First, the mother's educational aspirations for extrinsic values rather than for intrinsic values has an effect on private educational expenditures. Unless the mother's educational aspirations have been changed to pursuing intrinsic values, the private educational expenditures cannot be reduced. Second, the polarization of the household's income and assets could bring about the polarization of private educational expenditures, which can lead to the intergenerational income polarization.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.310-316
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• 2010

Recently a fuel oil of the diesel engine of the marine ship is being changed with heavy oil of low quality as the oil price is higher more and more. Therefore the wear and corrosion in all parts of the engine such as cylinder liner, piston crown, spindle and seat ring of exhaust valves are predominantly increased. In particular the degree of wear and corrosion of piston crown is more seriously compared to the other parts of the engine due to operating in severe environment such as the high temperature of exhaust gas and repeating impact. Thus the repair weldment of the piston crown is a unique method to prolong the its life in a economical point of view. In this case, filler metals having a high corrosion and wear resistance such as stellite 6, Inconel 625 and Inconel 718 are mainly being used for repair welding. However it has been often happened that piston crown on the ship,s job site is being actually inevitably welded with mild filler metals. Therefore in this study, filler metals such as E4301, E4313 and E4316 were welded at SS401 steel as the base metal, and corrosion property of their weld metals in the case of post weld heat treatment or not was investigated with some electrochemical methods such as measurement of corrosion potential, cathodic and anodic polarization curves, cyclic voltammogram and polarization resistance etc. in 0.1% $H_2SO_4$ solution. Corrosion resistance of the weld metal of E4301 was better than the other weld metals in the case of no heat treatment, however, its resistance was considerably decreased with post weld heat treatment(annealing:$625^{\circ}C$, 2 hr) compared to other weld metals. The weld metals of E4313 and E4316 showed a relatively good corrosion resistance by post weld heat treatment.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.163-168
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• 2003

In the present study, the piezoelectricity and polarization of multilayer ceramic actuator, being designed to stack PMN-PZ-PT ceramic layers and Ag-Pd electrode layers alternatively, were investigated under a consideration of geometric factor, the volume ratio of the ceramic to the electrode layers. The actuators were fabricated by tape casting of $0.2Pb(Mg_{1/3}Nb_{2/3)O_3-0.38PbZrO_3-0,42PbTiO_3$ followed by lamination and burnout & co-firing processes. The actuators of $10\times10\times0.6~2\textrm{mm}^3$ in size were formed in a way that $60 ~ 200\mu\textrm{m}$ thick were stacked alternatively with $5\mu\textrm{m}$ thick electrode layer. Increases in polarization and electric field-induced displacement with thickness of the ceramic layer were attributed to change of $90^{\circ}$/$180^{\circ}$ domain ratio, which was affected by interlayer internal stress. The piezoelectricity and actuation behaviors were found to depend upon the volume ratio (or thickness ratio) of ceramic to electrode layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.74-75
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• 2006

We have investigated dielectric properties depending on temperature in organic light-emitting diodes using 8-hydroxyquinoline aluminum ($Alq_3$) as an electron transport and emissive material. We analyzed the dielectric properties of organic light-emitting diodes using characteristics of impedance. he Impedance characteristics was measured complex impedance Z and phase $\theta$ in the temperature range of 10 K to 300 K. We obtained complex electrical conductivity, dielectric constant and loss tangent ($tan{\delta}$) of the device at room temperature. From these analyses, we are able to interpret a conduction mechanism and dielectric properties contributed by an interfacial and orientational polarization.

• Journal of Korean Society of Disaster and Security
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• v.15 no.3
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• pp.47-55
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• 2022

Hate crimes should be viewed as a social problem, not a personal crime, and a preventive system should be established to have an acceptance system for people who can engage in antisocial behavior outside of the social integrated value norms. In particular, in order to reduce tragic hate crimes, society and the government should actively work to resolve polarization, and personality education linked to families, schools, and society should be provided, and policies to establish social safety network such as social security systems should be prepared. In addition, it is necessary to switch to a society in which principles are emphasized, and a society that cares for the weak rather than the strong, rather than the expedient policy of words.