• Restorative Dentistry and Endodontics
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• 제33권2호
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• pp.125-132
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• 2008

이 연구의 목적은 서로 다른 접착제들로 수리된 복합 레진의 전단 결합 강도를 비교하고, 접착 시스템이 복합레진의 수리 강도에 미치는 영향을 평가하기 위한 것이다. 40개의 복합 레진 시편 (Z-250)을 준비하였으며, 1주일 동안 열순환을 시행한 후, $50\;{\mu}m$ 알루미나 입자로 샌드 블라스팅 하였다. 이 시편들을 네 개의 그룹으로 나누었으며 (n = 10), 다음과 같은 서로 다른 종류의 접착제를 각각 적용하였다; SB 그룹 : Scotchbond multipurpose ; SE 그룹 : Clearfil SE bond ; XP 그룹 : XP bond ; XE 그룹 : Xeno III. 접착 과정을 완료한 후에, 새로운 레진 (Z-250, 3M ESPE)을 몰드에 적용하여, 광조사 하였다. 대조군으로, 접착 과정 없이 10개의 시편을 준비하였다. 7일 동안 열순환을 시행한 후 전단 결합 강도를 측정하였고, 파절 양상을 조사하였으며, 다음과 같은 결과를 얻었다. 1. 기존 복합 레진과 수리용 복합 레진 사이의 전단 결합 강도는 접착제 종류에 따른 유의한 차이를 보이지 않았다. 2. 재료의 응집 강도 (대조군)와 수리한 결합 강도 (실험군) 사이에 유의한 차이를 보이지 않았다. 3. 파절 양상은 대부분 응집성 파절 또는 혼합 파절을 보였다.

• 동력기계공학회지
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• 제7권2호
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• pp.73-79
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• 2003

The present study was aimed at analysing the damage of a used gas turbine bucket after 39,500h of total service. Microstructures and cracks of service-induced bucket were observed. The crack might have initiated from the coating in the bucket surface by thermal fatigue and propagated into the GTD111 base metal. Maximum depth of penetration was 2.7 mm(full penetration) at the leading edge. Crack contains a lot of Cr-,Ti-,Al-oxide which will prohibit filling and wetting of insert metal. Depth and propagation direction of crack were accorded with centrifugal force and temperature distribution in turbine bucket. Present result will provide basic data for repair bonding process.

• Applied Science and Convergence Technology
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• 제26권3호
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• pp.43-46
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• 2017

Aluminum-doped ZnO (AZO) thin films were deposited by atomic layer deposition (ALD) with respect to the Al doping concentrations. In order to explain the chemical stability and electrical properties of the AZO thin films after hydrogen peroxide ($H_2O_2$) solution immersion treatment at room temperature, we investigated correlations between the electrical resistivity and the electronic structure, such as chemical bonding state, conduction band, band edge state below conduction band, and band alignment. Al-doped at ~ 10 at % showed not only a dramatic improvement of the electrical resistivity but also excellent chemical stability, both of which are strongly associated with changes of chemical bonding states and band edge states below the conduction band.

• 한국분말재료학회지
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• 제14권1호
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• pp.44-49
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• 2007

In the fabrication of dye-sensitized solar cells (DSSCs), carbon counter electrode has been tested for replacing the platinum counter electrode which has two drawbacks: limited surface area and high material cost. Poor mechanical stability of carbon layer due to weak bonding strength to electrically conductive TCO (transparent conducting oxide) glass substrate is a crucial barrier for practical application of carbon counter electrode. In the present study a carbon counter electrode with high conversion efficiency, comparable to Pt counter electrode, could be fabricated by adaption of a bonding layer between particulate carbon material and TCO substrate.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1996년도 특별강연 및 춘계학술발표 개요집
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• pp.6-9
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• 1996

The Joining of copper rod and zirconia tube was carried out in Ar gas atmosphere. There are two type of the joining. The one is the reaction bond consisting of Cu and zirconia was dominated by surface reaction wi th a undetctable very thin layer. It was found that copper elements were diffused to zirconia side, but that most of Z $r^{4+}$ ions were not diffused to copper side. This result means application of a DC voltage to migrate oxygen to the copper/zirconia interface can oxidize metal at the copper /zirconia interface, and the bonding reaction between zirconia and copper oxide may occur. The other is the reaction bonding was dominated by interdiffusion with a very thick interface layer. This result means application of a DC voltage can reduce zirconia at the interface. The bonding reaction is to be an alloying between Zr and Cr.

• 한국정밀공학회지
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• 제26권12호
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• pp.9-17
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• 2009

• 전기학회논문지P
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• 제57권4호
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• pp.444-450
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• 2008

There are several ways to bond to building grounding systems for reducing GPR(ground potential rise) and EMI resulting from power system faults or lightning stroke to building. In order to verify effective bonding practice, the GPR and voltage of equipment due to the direct stroke to building are calculated with ATP-EMTP model for transformer, transmission line and MOV(Metal oxide varistor). The simulated model shows a satisfactory accuracy compared with experimental result for the $8/20{\mu}s$ simulated current pulse. It is observed that separate grounding can cause dangerous voltage to the building equipment and the performance of surge protective device can improve when it is installed to the protected equipment in distance as short as possible.

• 대한치과기공학회지
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• 제28권1호
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• pp.19-26
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• 2006

The effect of Nb on interfacial bonding characteristics of Ni-Cr alloy for porcelain fused to metal crown (PFM) has been studied in order to investigate oxide layer. A specimens of Ni-Cr alloy, which is 0.8mm in thickness, within the porcelain furnace of 1,000$^{\circ}C$ with four tests such as air, vacuum, air for 5 minutes and vacuum for 5 minutes in order to examine an oxide behavior of alloy surface generated by the adding of Nb to be controlled at a rate of 0, 1, 3 and 5. Oxide film was observed form of the fired specimens with scanning electron microscope (SEM), and at the same time it measured Electron Probe Micro Analyzer (EPMA). The result of this study were as follows: 1. Cr oxide film and Nb oxide film were observed from the surface of specimen to be controlled at a rate of Nb 1%. 2. Nb oxide film was observed from the interface of specimens to be controlled at a rate of Nb 1% and 3%. 3. The stability of oxide films that treated in air were more stable than treated under vacuum.

• 한국염색가공학회지
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• 제14권5호
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• pp.261-267
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• 2002

Cotton fabrics were immersed in aqueous solution of N-methylmorpholine N-oxide(NMMO) with various concentrations, padded by 300% of pick-up, concentrated at $90^\circ{C}$ for 30min under constant-length condition, washed, and dried, to examine a possibility of linen-like finishing by the solvent bonding between fibers. With increasing the concentration of NMMO, cross-sections of fibers changed to oval or polygonal shapes and not only the fibers but also the warp and weft were bonded each other, which produced linen-like effect on the fabrics in the aspects of appearance and mechanical properties such as the Increase of stiffness and shear properties. The thickness, moisture regain and dyeability were increased with the concentration of NMMO.

• 한국물환경학회지
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• 제27권4호
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• pp.486-490
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• 2011

As(V) adsorption on aluminum oxide powder which was recycled from industrial wastes containing aluminum hydroxide was evaluated. Aluminum oxide powder in this study was prepared by calcinating aluminum hydroxide wastes at$550^{\circ}C$. Spectroscopic analysis indicated that the aluminum hydroxide wastes were changed to aluminum oxide by calcination. Arsenic adsorption isotherm was conducted with variation of ionic strength and multiple-ion systems using Ca(II) and Cu(II). As(V) removal showed typical anionic adsorption characteristics that the removal efficiency decreased with increasing pH in single As(V) system as well as in binary and ternary system. More than 80% of As(V) at an initial concentration of $5{\times}10^{-5}$ M was removed from aluminum oxide powder in As(V) single system. The effect of ionic strength on As(V) adsorption was negligible, which indicated the strong bonding between aluminum oxide powder and As(V). The removal efficiency of As(V) was higher in a binary system with Cu(II) than in a binary system with Ca(II).