• Korean Journal of Materials Research
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• v.14 no.12
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• pp.863-869
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• 2004

The purpose of this research is to investigate the mechanical property and ductile-brittle transition temperature of Ti-Nb-P added extra low carbon interstitial free steel having a tensile strength of 440 MPa. The mechanical property and transition temperature of hot rolled steel sheets were more influenced by the coiling temperature rather than by the small amount of alloying element. Further, at the same composition, the property of the specimen coiled at low temperature was superior to that obtained at higher coiling temperature. The fracture surface of 0.005C-0.2Si-1.43Mn steel coiled at $630^{\circ}C$ showed a ductile fracture mode at $-100^{\circ}C$, but coiling at $670^{\circ}C$ showed a transgranular brittle fracture mode at $-90^{\circ}C$. The galvannealed 0.006C-0.07Si-1.33Mn steel sheet annealed at $810^{\circ}C$ has tensile strength and elongation of 442.8 MPa and $36.6\%$, respectively. The transition temperature of galvannealed 0.006C-0.07Si-1.33Mn steel sheet was increased with a drawing ratio, and the transition temperature of the galvannealed 0.006C-0.07Si-1.33Mn steel was $-60^{\circ}C$ at a drawing ratio of 1.8

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.862-865
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• 2011

WebGL is a cross-platform web standard for a low-level 3D graphics API based on OpenGL ES 2.0 and presents 3D graphics in web browsers without installing extra plug-ins. The reason that WebGL is notable is because it is included in the HTML5 standard which is getting the spotlight as a next-generation RIA(Rich Internet Application) platform for variable devices such as PCs, smart phones, table PCs, and smart TVs. In this research, we would like to introduce and develop a behavior engine for easy and rapid authoring of complicated interactions and 3D object's behavior models in WebGL-based contents.

• Geomechanics and Engineering
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• v.29 no.6
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• pp.627-643
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• 2022

Water-rock interactions have a significant influence on the mechanical behavior of rocks. In this study, uniaxial compression and tension tests on different water-treated sandstone samples were conducted. Acoustic emission (AE) monitoring and micro-pore structure detection were carried out. Water-rock interactions and their effects on rock mechanical behavior were discussed. The results indicate that water content significantly weakens rock mechanical strength. The sensitivity of the mechanical parameters to water treatment, from high to low, are Poisson ratio (𝜇), uniaxial tensile strength (UTS), uniaxial compressive strength (UCS), elastic modulus (E), and peak strain (𝜀). After water treatment, AE activities and the shear crack percentage are reduced, the angles between macro fractures and loading direction are minimized, the dynamic phenomenon during loading is weakened, and the failure mode changes from a mixed tensile-shear type to a tensile one. Due to the softening, lubrication, and water wedge effects in water-rock interactions, water content increases pore size, promotes crack development, and weakens micro-pore structures. Further damage of rocks in fractured and caved zones due to the water-rock interactions leads to an extra load on the adjoining coal and rock masses, which will increase the risk of dynamic disasters.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.3
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• pp.81-87
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• 2015

In order to effectively protect electrical and electronic circuits which are extremely susceptible to lightning surges, multi-stage surge protection circuits are required. This paper presents the operational characteristics of the two-stage hybrid surge protection circuit in extra-low voltage DC power lines. The hybrid surge protective device consists of the gas discharge tube, transient voltage suppressor, and series inductor. The response characteristics of the proposed hybrid surge protective device to combination waves were investigated. As a result, the proposed two-stage surge protective device to combination wave provides the tight clamping level of less than 50V. The firing of the gas discharge tube to lightning surges depends on the de-coupling inductance and the rate-of-change of the current flowing through the transient voltage suppressor. The coordination between the upstream and downstream components of the hybrid surge protective device was satisfactorily achieved. The inductance of a de-coupler in surge protective circuits for low-voltage DC power lines, relative to a resistance, is sufficiently effective. The voltage drop and power loss due to the proposed surge protective device are ignored during normal operation of the systems.

• Journal of Ocean Engineering and Technology
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• v.26 no.5
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• pp.87-93
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• 2012

Many longitudinally-arranged pipes in ships are equipped with loops as a measure to reduce stresses caused by displacement loads conveyed from the hull girder bending and/or thermal loads of carried fluid of non-ambient temperature. But as the loops have some negative effects such as causing extra manufacturing cost and occupying extra space, the number and the dimensions of the loops need to be minimized. In the meanwhile, a design formula for pipe loops has been developed by modeling them as a spring element of which stresses and axial stiffness are calculated based on the beam theory. But as the beam theory turns out to be inappropriate to deal with the complex structural behavior in the curved corner portion of the loop, this paper aims at improving the previously developed design formula by adopting correction factors which can allow for the gap between the results of beam theory and a more accurate analysis. This paper adopts a finite element analysis with two-dimensional shell elements with some validation work for it. The paper ends with a sample application of the proposed formulas showing their accuracy and efficiency.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.34.2-34.2
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• 2010

We built 7 potential extra-terrestrial planets including the full 3D Earth model with various surface types and 6 planet models, each with uniform surface characteristics. The surface types include ice, tundra, forest, grass, ground and ocean. We then imported these 7 planets into integrated ray tracing(IRT) model to compute their disk averaged spectra and to understand the spectral behavior depending on the geometrical view, illumination phase and seasonal change. The IRT computation show that the 6 planets with uniform surfaces exhibit clear spectral differences from that of the Earth. We then built a phase and seasonal DAS database for the 6 uniform surface planets and used them for parametric spectral decomposition technique to derive the Earth DAS. This computation resulted in the first potential solution to the surface type ratio of the Earth compared to the measured earth surface type ratio. The computational details and the implications are discussed.

• Current Optics and Photonics
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• v.6 no.3
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• pp.282-287
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• 2022

Narrowing the spectral linewidth and improving the wavelength stability of high-power laser diodes (HPLDs) are both in high demand for rapidly maturing industrial laser applications. In this study, we investigate the spectral behavior of a commercial HPLD bar module composed of 19 laser diodes (LDs) in a single-layered bar with a built-in volume Bragg grating (VBG) and an additional cascaded VBG. Optical loss due to the extra cascaded VBG is kept below 5% when the optical output is 5 W or more. The full width at half maximum of the Fabry-Perot peak from the cascaded VBG is reduced to about 12.4% and 29.1% at the edge (1^st LD) and center (10^th LD) of the HPLD bar module respectively, compared to using only a built-in VBG at an optical power of 10 W or more. In addition, fine wavelength tuning is achieved by temperature control of the extra VBG, and the obtained wavelength-tuning range amounts to about 10.6 pm/K.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.574-586
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• 2019

This study was conducted to obtain meaningful information about job management of child care center teachers, who take charge of child care policy at the front line, social meaning of which is being greatly highlighted these days. Especially, the research was designed with causal relationships in mind, in which certain job-related thoughts or consciousness forms attitudes, thus leading to behavior. In this light, the present study selected the following variables for analysis: job attitudes including job calling, job engagement, and job burnout; and job behavior such as creative behavior, active behavior, and ethical behavior. Data collected from 209 child care center teachers' response to structured questionnaires was analyzed, using t-test, one-way analysis of variance (one-way ANOVA), and hierarchical regression analysis. The results indicate that job burnout increased at a statistically significant level as extra workhours increased, and that only job engagement, among job attitude variables, and creative behavior and active behaviors, among job behavior variables, had significant effects. Moreover, job engagement was the only variable that was found to work as a mediator in relationships between job calling and active behavior.

• Management & Information Systems Review
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• v.30 no.3
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• pp.107-132
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• 2011

The purposes of this paper are to examine the effect of emotional intelligence and logic intelligence on organizational citizenship behavior and to examine the moderating effect of intelligence labor on these relationship. For these purposes, literature review and survey research were conducted. The 420 questionnaires were sent to the 12 manufactural firms in the Busan and Kyungsang Nam-Do region for empirical analysis. Total 363 usable responses were collected(effective response rate : 86.40%). The major findings of the empirical research are as follows ; First, emotional intelligence and logic intelligence have positive influence organizational citizenship behavior. but emotional intelligence have more positive influence than logic intelligence on organizational citizenship behavior. Second, emotional intelligence has differential influence on organizational citizenship behavior by emotional labor, but logic intelligence hasn't that. In conclusion, emotional intelligence is expected to improve organizational citizenship behavior which is extra-role behavior in an organization. Therefore, managers have to develop organizational citizenship behavior by exhibiting emotional intelligence, considering emotional labor.

• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.135-143
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• 2018

Normally there is a one-time relationship between stakeholders in the construction projects. Thus, project participants are easily exposed to opportunistic behavior. According to the theory of transaction costs, a contract effectively influence the behavior of counter-party. The important role of contracts in limiting opponent opportunistic behavior has been academically acknowledged and studied in inter-firm relationships. The purpose of this study is to reveal the mediating effect of the contract on the power of the contractor in the contractor's behavior. Power is divided into mediated and non-mediated power. We surveyed construction companies' employees who have conducted construction projects. Based on the questionnaire response, we examined the influence of the Employer's power on the behavior of the contractor. Both non-mediated power and mediated power were significant for in-role and out-role behaviors. Both non-mediated power and mediated power were found to have a significant effect on the control and coordination function of contracts. The results show that the control function of the contract is significant for the in-role behavior and the extra-role behavior. Finally, the mediating effect of the contract function was significant only in the control function.