• Journal of Welding and Joining
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• 제19권6호
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• pp.608-613
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• 2001

In this study, the rotary bending fatigue test was carried out with two kinds of base metal, martensite stainless steel STR3 and austenite stainless steel STR35 and the dissimilar friction welded material with them. To compare the fatigue fifes according to the notch positions, the small circular defect was worked on the bonded line, 1.0mm and 0.5mm distance form the bonded line. The fatigue limits of the STR3 and STR35 base metal were 429.0MPa and 409.4MPa respectably. In comparison with fatigue life at the same notch positions, the STR35 specimens showed about 190% for base metal, 82% for 1.0mm distance notched specimens higher than that of the STR3. But the fatigue life of the 0.5mm distance notched STR35 specimen showed about 35% lower than that of the STR3 specimen. And the bonded line notched specimen was much lower fatigue life than the other specimens because of separation of the bonded line.

• 전기학회논문지
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• 제58권10호
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• pp.1881-1887
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• 2009

This paper discusses the effects of ECC (Earth Continuity Conductor) for reducing the level of induced sheath overvoltages at the single point bonded section of combined transmission lines which are mixed underground power cable with overhead line in one T/L. In previous papers, the characteristics of ECC on only underground power cable systems were sufficiently analyzed. However, the result of only underground power cable systems are totally different from that of combined transmission lines because ECC is commonly grounded with overhead grounding wire at mesh of cable head. Therefore, in this paper, the installation effects of ECC have been variously analyzed considering the three kinds of fault positions, cable formation of duct and trefoil, spacing between phase conductor and ECC, and the change of overhead transmission line section length on 154kV combined transmission line. Finally, simulation results show that ECC can effectively reduce the induced sheath voltage.

• 전자공학회논문지A
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• 제32A권3호
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• pp.134-142
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• 1995

We discovered that each distinct shape of the roof-shaped peaks of (111) facets, which are generated on (110) cross-section of the directly bonded (100) silicon wafer pairs after KOH etching, can be mapped to one of three conditions of the interfacial oxide existing at the bonding interface as follows. That is, thick solid line can be mapped to stabilization, thin solid line to disintegration, and thin broken line to spheroidization. also we confirmed that most of the interfacial oxides of a well-aligned wafer pairs were disintegrated and spheroidized through high-temperature annealing process above 900$^{\circ}$C while the oxide was stabilized persistently when two wafers are bonded rotationally around their common axis perpendicular to the wafer planes.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2000년도 특별강연 및 추계학술발표대회 개요집
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• pp.124-126
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• 2000

The fatigue crack propagation characteristics were investigated for two kind of heat-resisting steel(STR3 and STR35) commonly using in valve material of vehicles. From the experiment, the fatigue life of the specimens notched at bonded line was shown about 19.7％ and 72.2％ lower and the specimens notched at 1.0mmdistance from bonded line was shown about 25.2％ and 99.1％ higher than that of the base metal respectably.

• Composites Research
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• 제16권4호
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• pp.51-58
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• 2003

접착 조인트의 안전성은 사용되는 열경화성 접착제의 경화상태에 많은 영향을 받기 때문에, 실시간으로 접착 조인트의 경화를 모니터링 할 수 있다면 조인트의 품질을 향상시킬 수 있다. 본 연구에서는 조인트의 경화 중 접학제의 소산계수를 측정하여 이를 접착제의 경화도로 환산할 수 있는 기법을 제안하였다. 접착제의 소산계수와 경화도의 관계를 실험적으로 연구하였으며, 온도와 경화도에 따라 민감하게 변하는 소산계수로부터 온도가 미치는 영향을 제거하였다. 연구결과 접착제의 소산계수는 그 경화율과 유사한 경향을 보임을 알 수 있었다.

• Journal of the Korean Wood Science and Technology
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• 제43권1호
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• pp.60-67
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• 2015

국내산 낙엽송 집성재와 봉형 GFRP의 접착성능을 평가하기 위해 집성재에 선공을 한 후 봉형 GFRP를 삽입하고 접착제로 목재와의 간극을 충진시켜 인발시험편을 제작하였다. 인발시험편은 접착 깊이, 접착층 두께, 접착제 종류를 다르게 적용하여 실험하였다. 봉형 GFRP를 삽입접착한 캔틸레버형 라멘구조 시험체는 인발시험 결과를 토대로 제작, 강판삽입형 시험체와 모멘트 저항 성능을 비교검토 하였다. 인발시험결과 봉형 GFRP의 삽입깊이가 봉형 GFRP 직경의 5배일 때 가장 우수한 접착력이 측정되었으며, 접착층 두께는 1 mm일 경우 2 mm일 때보다 17%~29% 향상된 접착력이 측정되었다. 또한 폴리우레탄(poly-urethane) 접착제를 사용한 시험편이 레조시놀(resorcinol) 접착제를 사용한 시험편보다 2.9~4.0배 높은 성능을 발휘하였다. 봉형 GRFP로 접합한 캔틸레버형 라멘구조 시험체는 드리프트 핀을 사용한 강판삽입형 시험체와 비교하여 평균 0.82배 낮은 모멘트 저항 성능이 측정되었지만 초기강성은 0.93배로 대등한 성능을 보였다.

• 한국표면공학회지
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• 제53권5호
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• pp.227-231
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• 2020

This article investigated the effects of stainless steel plate-patterns bonded to aluminum frypan on the thermal distortion and surface temperature of the frypan during gas or induction heating. Two different stainless steel plate-patterns were employed: type A contains only circular holes and type B has not only circular holes but also vacant spaces of 0.5 mm thick and 40 mm long straight line crossing 60 mm long curved line. The bottom of the frypan was distorted during heating when type A stainless steel plate-bonded frypan while no significant thermal distortion was observed for type B stainless steel plate-bonded frypan during heating. Temperature of the frypan surface showed the same trend during gas heating, irrespective of stainless steel plate-patterns. During induction heating, however, the frypan with type B stainless steel plate-pattern showed lower surface temperature than the frypan with type A stainless steel plate-pattern. It is concluded that Type B stainless steel plate-pattern with circular holes and vacant spaces of lines is very effective for minimizing a thermal distortion and lowering the surface temperature of an aluminum frypan during induction heating.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.316-319
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• 2008

The L-bending of inner-structure bonded sandwich sheet metal is examined by using a bending die attached to the material testing machine. The specimen is composed of top and bottom layers and a middle layer of pyramid-core structure and each layer is bonded by brazing. The variables chosen for experiments were clearance between punch and die, location of bend line on the specimen surface and clamping type of specimen during L-bending. Effects of these variables on deformation of specimen around die-corner radius were investigated. It was shown that the irregular shapes of recess are formed in the inner layer of bended parts and they greatly depend on working conditions.

• 대한기계학회논문집A
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• 제28권4호
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• pp.435-442
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• 2004

This paper presents a hermetic MEMS on-chip package bonded by a closed-loop AuSn solder-line. We design three different package specimens, including a substrate heated specimen without interconnection-line (SHX), a substrate heated specimen with interconnection-line (SHI) and a locally heated specimen with interconnection-line (LHI). Pressurized helium leak test has been carried out for hermetic seal evaluation in addition to the critical pressure test for bonding strength measurement. Substrate heating method (SHX, SHI) requires the bonding time of 40min. at 400min, while local heating method (LHI) requires 4 min. at the heating power of 6.76W. In the hermetic seal test. SHX, SHI and LHI show the leak rates of 5.4$\pm$6.7${\times}$$^{-10}$ mbar-l/s, 13.5$\pm$9.8${\times}$$^{-10}$ mbar-l/s and 18.5$\pm$9.9${\times}$$^{-10}$ mbar-l/s, respectively, for an identical package chamber volume of 6.89$\pm$0.2${\times}$$^{-10}$. In the critical pressure test, no fracture is found in the bonded specimens up to the applied pressure of 1$\pm$0.1MPa, resulting in the minimum bonding strength of 3.53$\pm$0.07MPa. We find that the present on-chip packaging using a closed AuSn solder-line shows strong potential for hermetic MEMS packaging with interconnection-line due to the hermetic seal performance and the shorter bonding time for mass production.

• 대한치과기공학회지
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• 제27권1호
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• pp.73-78
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• 2005

The surface-reacted layer of titanium castings greatly affects their mechanical properties. This study analyzed the interfacial zone of Ti-20%Zr-5%Cr alloy castings obtained from phosphate bonded investment and examined the relationship between the surface-reacted layer and hardness. The Vickers hardness of cast disks were tested at 20$\mu m$ intervals from the surface to 120$\mu m$ in depth. The cross-section was observed metallurgically, and line profile of the reacted layer was conducted under the EDX. The surface-reacted layer of Ti-20%Zr-5%Cr alloy is showed a similar tendency to Ti-6%Al-4%V alloy in thickness, and also Si diffusion in multiple reacted layer of Ti-20%Zr-5%Cr alloy is less than cp Ti and similar to Ti-6%Al-4%V alloy. The Vickers hardness in the surface layer was greater than in the inner part, and the Vickers hardness of Ti-20%Zr-5%Cr alloy ranged 650 to 390 and cp Ti ranged 810 to 160, Ti-6%Al-4%V alloy ranged 710 to 530 respectively.