• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.549-556
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• 2002

Geotextile tubes hydraulically or mechanically filled with dredged materials have been applied in hydraulic and coastal engineering in recent years(shore protection structure, detached breakwater, groins and jetty). It can also be used to isolate contaminated material from harbor, detention basin dredging, and to use this unit as dikes for reclamation work. Recently, new preliminary design criteria supported by model and prototype tests, and some stability analysis calculations have been studied. The stability analysis of geotextile tube is composed geotechnical and hydrodynamic analysis. The stability check points are sliding failure, overturning, bearing capacity failure against the wave attack. In this paper presented the construction procedure and in-situ measurement(properties of filling material, effective height variation, stress variation at geotextile tube bottom) of geotextile tube at Young-Jin Bay and stability analysis by theoretical method and hydraulic model tests

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.215-218
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• 1998

The thermal stability of polyaniline-camphorsulfonic acid(PANI-CSA) film was studied as a function of temperature and time. A decrease in electrical conductivity of PANI-CSA film occurred when PANI-CSA film is subjected to temperature above 60$^{\circ}C$. From the result of thermogravimetry (TG), it was thought that the deterioration in electrical conductivity of PANI-CSA film was due to evaporation of water and residual solvent.

• Journal of Korean Dental Science
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• v.1 no.1
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• pp.22-27
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• 2008

Purpose : This study sought to evaluate the dimensional stability of the SITT (Silicone Index Tooth Tray) impression system and to determine whether providing space for wash impression material in SITT is a necessary step in obtaining accurate prostheses. Materials and methods : After mounting metal dies with shoulder and chamfer margins arbitrarily, SITT was fabricated using Blu-mousse$^{(R)}$. To test the dimensional stability of the SITT system for margin design, the shoulder margin and chamfer margin were evaluated. Furthermore, to test the effect of space for wash impression material, 0.5mm space in SITT and zero space in SITT were statistically compared. Results : 1. There was no significant difference between the group with shoulder margin and that with chamfer margin. 2. There was no significant difference between the group with 0.5mm space and that with zero space for wash impression material. Conclusions : Considering the limitations of this study, the dimensional stability of the SITT system did not interfere with the margin design. Space for the wash impression material was also unnecessary.

• Journal of Adhesion and Interface
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• v.21 no.2
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• pp.41-50
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• 2020

Organic-inorganic metal halide perovskite has shown a great promise in photovoltaic applications because of the skyrocketing power-conversion efficiencies up to 25.2% and their potentially low production cost. However, it also has critical issue of substantial material degradation during device operation to be overcome for successful commercialization. Understanding the nature of defects and their photochemistry related to material degradation is needed. Furthermore, strategy to passivate defects in perovskite should be adopted to improve the stability of perovskite. In this article, we present predominant defects formation in perovskite that contribute to material degradations in perovskite solar cells. We then discuss how material stability can be improved through reliable defect passivation engineering.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.3
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• pp.569-583
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• 1995

Disinfection of dental impressions are necessary due to contamination with patient’s saliva and blood, which is a potential for cross-infection. The purpose of this study was to evaluate the effects of disinfection of four hydrophilic rubber impression materials with three disinfecting solutions, on the dimensional stability and surface hardness of improved stone casts. Three hydrophilic vinyl polysiloxane impression materials(Express, Reprosil, Exafine) and one polyether impression material(Impregum-F) were mixed according to the manufacturer’s directions and impressions were made on a ADA specification No. 19 stainless-steeldie. On removal of the impressions, each impression was immersed in one of the disinfectants(Banicide, Potadine, Clorox) for 10 minutes. After disinfection, type IV improved stone. casts were poured. On this cast, the linear dimension and surface hardness were measuredusing a Measurescope(Nikon, Japan) and a Barcol hardness tester(Barber, Colman Co U. S. A). The results were as follows : 1. The improved stone casts from disinfected Reprosil and Impregum-F impression material did not show dimensional changes(P>0.01). Those from disinfected Express and Exafine impression material showed dimensional changes(P<0.01). The amount of shrinkage was not clinically significant. 2. The improved stone casts from disinfected Express impression material did not exhibit changes in surface hardness(P>0.01), but those from disinfected Reprosil, Exafine, Imp regnum-F impression material showed changes in surface hardness(P<0.01). 3. The dimensinal stability and surface hardness of the improved stone casts were satisfactory using Banicide on Express, all disinfectants used in this study on Reprosil, Potadin and Clorox on Exafine, Banicide and Clorox on Impregum-F. According to these results, immersion disinfection of hydrophilic rubber impression mate rials did not adversely affect the resultant casts. Nevertheless compatibility tests of impression materials and disinfectants should be done when disinfecting impressions.

• Electronic Materials Letters
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• v.14 no.6
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• pp.669-677
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• 2018

In this work, the high ${\kappa}$ $Zr_xAl_{1-x}O_y$ films with a different Zr concentration have been deposited by atomic layer deposition, and the effect of Zr concentrations on the structure, chemical composition, surface morphology and dielectric properties of $Zr_xAl_{1-x}O_y$ films is analyzed by Atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and capacitance-frequency measurement. The effect of Zr concentrations of $Zr_xAl_{1-x}O_y$ gate insulator on the electrical property and stability under negative bias illumination stress (NBIS) or temperature stress (TS) of ZnSnO (ZTO) TFTs is firstly investigated. Under NBIS and TS, the much better stability of ZTO TFTs with $Zr_xAl_{1-x}O_y$ film as a gate insulator is due to the suppression of oxygen vacancy in ZTO channel layer and the decreased trap states originating from the Zr atom permeation at the $ZTO/Zr_xAl_{1-x}O_y$ interface. It provides a new strategy to fabricate the low consumption and high stability ZTO TFTs for application.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.411-419
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• 2023

In this paper, NIMONIC 86 material was tried to apply to exhaust valve for small-sized marine diesel engine. The both structural stability and thermal resistance in high temperature were needed to use the NIMONIC 86 material as exhaust valve for small-sized marine diesel eng ine. The purpose of this study is to investig ate the application of NIMONIC 86 material to exhaust valve of small-sized marine diesel engine by comparing, respectively, SUH 3 and STS 316 materials. As the results, NIMONIC 86 material has intermediate characteristics between SUH 3 and STS 316 materials in terms of the strength in condition of room temperature. Further NIMONIC 86 material was evaluated to have better characteristics than SUH 3 and STS 316 materials in terms of the thermal conductivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.472-475
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• 2001

The electrical properties and stability of ZPCCY-based varistors composing of ZnO-Pr$_{6}$ O$_{11}$ -CoO-Cr$_2$O$_3$-Y$_2$O$_3$ ceramics were investigated with sintering time. As sintering time is increased, the nonlinear exponent decreased in the range of 51.19∼26.70. Among varistors having above 30 in nonlinear exponent, for the varistor sintered for 1h, the nonlinearity was superior to the stability comparatively and, in the case of 2h, the stability was superior to the nonlinearity relatively. Consequently, it is estimated that the varistors sintered for 1∼2h will be applied to various fields by trade-off between nonlinearity and stability.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.8
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• pp.530-534
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• 2017

Transparent film heaters employing silver nanowires (Ag NWs) have attracted increasing attention because of their widespread applications. However, the low thermal resistance of Ag NWs limits the maximum operating temperature of the Ag NW film heater. In this study, Ag NW film heaters with high mechanical and thermal stability were successfully developed. The thermal power-out characteristics of the Ag NW heaters were investigated as a function of the Ag NW density. The results revealed that the prepared flexible Ag NW heater possessed high thermal stability over $190^{\circ}C$ owing to ZnO encapsulation. This indicates that the Ag NW film with excellent thermal stability have remarkably high potential for use as electrodes in film heaters operating at high temperatures.

• Steel and Composite Structures
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• v.41 no.6
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• pp.775-785
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• 2021

Analysis of nonlinear stability behaviors of composite magneto-electro-elastic (MEE) nano-scale shells have been represented in this reaserch. The shell is assumed to be under a transverse mechanical load. Composite MEE material has been produced form piezoelectric and magnetic ingradients in which the material charactristics may be varied according to the percentages of the ingradients. The governing equations including scale effects have been developed in the framework of nonlocal elasticity. It has been demonstrated that nonlinear stability behaviors of MEE nano-sized shells in electrical-magnetic fields rely on the percentages of the ingradients. Also, the efficacy of nonlocality parameter, magnetic intensities and electrical voltages on stability loads of the nanoshells have been researched.