• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2001년도 Proceedings of 6th International Joint Symposium on Microeletronics and Packaging
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• pp.35-43
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• 2001

Flip chip assembly on organic substrates using ACAs have received much attentions due to many advantages such as easier processing, good electrical performance, lower cost, and low temperature processing compatible with organic substrates. ACAs are generally composed of epoxy polymer resin and small amount of conductive fillers (less than 10 wt.%). As a result, ACAs have almost the same CTE values as an epoxy material itself which are higher than conventional underfill materials which contains lots of fillers. Therefore, it is necessary to lower the CTE value of ACAs to obtain more reliable flip chip assembly on organic substrates using ACAs. To modify the ACA composite materials with some amount of conductive fillers, non-conductive fillers were incorporated into ACAs. In this paper, we investigated the effect of fillers on the thermo-mechanical properties of modified ACA composite materials and the reliability of flip chip assembly on organic substrates using modified ACA composite materials. Contact resistance changes were measured during reliability tests such as thermal cycling, high humidity and temperature, and high temperature at dry condition. It was observed that reliability results were significantly affected by CTEs of ACA materials especially at the thermal cycling test. Results showed that flip chip assembly using modified ACA composites with lower CTEs and higher modulus by loading non-conducting fillers exhibited better contact resistance behavior than conventional ACAs without non-conducting fillers. Microwave model and high-frequency measurement of the ACF flip-chip interconnection was investigated using a microwave network analysis. ACF flip chip interconnection has only below 0.1nH, and very stable up to 13 GHz. Over the 13 GHz, there was significant loss because of epoxy capacitance of ACF. However, the addition of $SiO_2filler$ to the ACF lowered the dielectric constant of the ACF materials resulting in an increase of resonance frequency up to 15 GHz. Our results indicate that the electrical performance of ACF combined with electroless Wi/Au bump interconnection is comparable to that of solder joint.

• Journal of Welding and Joining
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• 제34권6호
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• pp.28-34
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• 2016

Galvannealed(GA) steels are now generally used in car body manufacturing for corrosion resistance. In this study, the weldability and joint mechanical behavior of a newly developed 1.2GPa grade GA ultra high strength TRIP(transformation induced plasticity) steel was investigated for three joining processes, such as adhesive bonding, resistance spot welding and weldbonding. Under both shear and peel stress conditions, the failure mode of the adhesive joints were the mixture of the adhesive cohesive failure, adhesive interface failure and coating layer failure. It means that the adhesion strength of GA coating onto the base metal was similar to that of adhesive bonding onto the GA coating. Under the shear stress condition, the weldbonding exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel because the strength of adhesive bond overwhelmed that of the resistance spot weld. Under the peel stress condition, the weldbonding also exerted to expand the optimal spot welding condition of 1.2GPa GA TRIP steel by inducing the tear fracture mode rather than the partial plug fracture mode.

• 대한골관절종양학회지
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• 제13권2호
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• pp.185-189
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• 2007

영상기술과 수술 술식의 발전으로 골반골의 악성종양에서 내 골반골 절제술이 보편화되었으나 절제 후 골 결손의 기능적인 재건 방법에 대하여는 아직 논란의 여지가 많다. 골반환 재건술식 중 열처리한 자가골과 대퇴골 전치환물을 조합하는 방법은 생역학적이며 해부학적인 적합성이 장점으로 적절한 증례를 선택하면 좋은 결과를 얻을 수 있다. 그러나 이 술식 후 감염이나 기계적인 파괴가 발생 시 내고정물과 자가골 전부를 제거하는 것이 불가피하다. 이런 경우 가관절을 형성하더라도 심한 하지 단축이 문제가 된다. 저자들은 이런 문제점을 해결하기 위해 대퇴골두를 제거하지 않고 골반골만 열처리 후 재삽입 한 1례를 보고하고자 한다.

• 한방재활의학과학회지
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• 제26권3호
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• pp.17-30
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• 2016

Objectives The purpose of this study was to find out the effects of ChondroT on arthralgia of the Collagenase-induced osteoarthritis in rats. Methods Osteoarthritis was induced into rat by injecting Collagenase in its knee joint. Rats are divided into a total of 8 groups (n=6). Normal group was not induced for osteoarthritis whereas control groups were induced for osteoarthritis by Collagenase. Positive-A (Indomethacin) was injected with Collagenase and after 8 days, 2 mg/kg of Indomethacin was medicated. Positive-B (JOINS TAB) was injected with Collagenase and after 8 days, 20 mg/kg of JOINS TAB was medicated. Experimental groups (Chondro T) at three dose levels (50, 100 and 200 mg/kg) were injected with Collagenase and after 8days they were medicated with 10 ml/kg. Indomethacin, JOINS TAB and ChondroT were medicated each substances once a day for 10 days. Thereafter, the changes in plantar withdrawal response of osteoarthritis rats by dynamic plantar aesthesiometer were observed and then RT-PCR analysis was done to investigate the expression of related proteins. Results 1. ChondroT significantly decreased withdrawal response of mechanical allodynia compared with control group in all of the experimental groups (ChondroT-A, ChondroT-B, ChondroT-C). 2. ChondroT significantly reduced Bax/Bcl-2 ratio in all of the experimental groups (ChondroT-A, ChondroT-B, ChondroT-C). 3. ChondroT significantly reduced the expression of INF-${\gamma}$ compared with control group in group ChondroT-B, ChondroT-C. Conclusions This results suggest that ChondroT may be meaningful for suppressing the pain of osteoarthritis. Further study is needed to conduct a rigorous clinical research.

• 한국세라믹학회지
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• 제55권5호
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• pp.492-497
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• 2018

This paper reports the efficacy of tape casting using an Ag-10 wt% CuO filler for the successful joining of a sintered $Ce_{0.9}Gd_{0.1}O_{2-{\delta}}-La_{0.7}Sr_{0.3}MnO_{3{\pm}{\delta}}$ (GDC-LSM) ceramic with a SUS 460 FC metal alloy by reactive air brazing. The as-prepared green tape was highly flexible without drying cracks, and the handling was easy when used as a filler material for reactive air brazing. Heat treatment for the GDC-LSM/SUS 460 FC joint was performed at $1050^{\circ}C$ for 30 min in air. Microstructural observations indicated a reliable and compact joining. The room temperature mechanical shear strength of the as-brazed joints was $60{\pm}8MPa$ with a cohesive failure. The flexural strength of joints was measured from room temperature up to $850^{\circ}C$, where the strength retention revealed to be almost 100% at $500^{\circ}C$. However, the joints showed a degradation in strengths at 800 and $850^{\circ}C$, exhibiting strength retentions of 57% and 37%, respectively.

• 한국공간구조학회논문집
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• 제12권2호
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• pp.81-88
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• 2012

텐세그리티 구조시스템의 한 종류인 케이블 돔 시스템은 케이블과 마스트로 이루어져 있다. 이 케이블에 외부하중이 가해지지 않은 상태에서 안정된 구조물이 되기 위하여 일정의 프리텐션이 가해져야 하며 구조물은 가해진 프리텐션 하에서 자기평형응력상태에 있어야 한다. 본 연구에서는 부재의 내력 벡터의 합 원리를 기초하여 자기평형 응력모드를 구하는 새로운 방법을 제안하였으며, 자기평형응력을 유지하기 위해 필요한 응력모드를 시각화할 수 있다는 점이 기존의 논문과 비교하여 독특성을 갖는다. 본 연구에서 제안된 방법에서 사용된 기본 원리는 모든 절점에서 외부하중이 가해지지 않은 상태에서 내력벡터의 합은 0이 되어야 한다는 것이다. 제안된 방법은 CAD를 이용하여 간단히 자기 평형응력모드를 찾을 수 있으며, 예제 케이블 돔 구조물을 대상으로 각 절점에 연결된 부재들의 내력을 결정하였다. 결과 값은 역학적 계산 방법과 기존의 이론에 의해 검증하였으며 잘 일치하였다.

• 전기학회논문지
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• 제61권12호
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• pp.1911-1919
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• 2012

In this paper, we focus on a robotic sealing process in which three robots are used. Each robot can be considered as a 7 axis redundant robot of which the first joint is prismatic and the last 6 joints are revolute. In the factory floor, robot path planning is not a simple problem and is not automated. They need experienced operators who can operate robots by teaching and playing back fashion. However, the robotic sealing process is well organized so the relative positions and orientations of the objects in the floor and robot paths are all pre-determined. Therefore by adopting robotic theory, we can optimally plan robot pathes without using teaching. In this paper, we analyze the sealing robot by using redundant manipulator theory and propose three different methods for path planning. For sealing paths outside of a car body, we propose two methods. The first one is resolving redundancy by using pseudo-inverse of Jacobian and the second one is by using weighted pseudo-inverse of Jacobian. The former is optimal in the sense of energy and the latter is optimal in the sense of manipulability. For sealing paths inside of a car body, we must consider collision avoidance so we propose a performance index for that purpose and a method for optimizing that performance index. We show by simulation that the proposed method can avoid collision with faithfully following the given end effector path.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.315-316
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• 2007

This paper presents a new methodology to improve movement database for a humanoid robot. The database is initially full of human motions so that the kinetics characteristics of human movement are immanent in it. then, the database is updated to the pseudo-optimal motions for the humanoid robot to perform more natural motions, which contain the kinetics characteristics of robot. for this, we use the evolutionary algorithm. the methodology consists of two processes : (1) the offline imitation learning of human movement and (2) the online generation of natural motion. The offline process improve the initial human motion database using the evolutionary algorithm and inverse dynamics-based optimization. The optimization procedure generate new motions using the movement primitive database, minimizing the joint torque. This learning process produces a new database that can endow the humanoid robot with natural motions, which requires minimal torques. In online process, using the linear combination of the motion primitive in this updated database, the humanoid robot can generate the natural motions in real time. The proposed framework gives a systematic methodology for a humanoid robot to learn natural motions from human motions considering dynamics of the robot. The experiment of catching a ball thrown by a man is performed to show the feasibility of the proposed framework.

• Advances in aircraft and spacecraft science
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• 제3권2호
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• pp.171-195
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• 2016

The present paper is a review of the main activities carried out within the context of the COMPTINN' program, a joint research project founded by a FUI program (Fonds $Unifi{\acute{e}}s$ $Interminist{\acute{e}}riels$) in which four research teams focused on the thermo-oxidation behaviour of HTS-TACTIX carbon-epoxy composite at 'high' temperatures ($120^{\circ}C-180^{\circ}C$). The scientific aim of the COMPTINN' program was to better identify, with a multi-scale approach, the link between the physico-chemical mechanisms involved in thermo-oxidation phenomena, and to provide theoretical and numerical tools for predicting the mechanical behaviour of aged composite materials including damage onset and development.

• 대한골관절종양학회지
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• 제8권2호
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• pp.48-53
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• 2002

상피암의 인접 골격근으로의 직접 전파는 많이 보고되었으나, 골격근으로의 원격전이는 드물고 특히 다발성 전이는 매우 드문 것으로 알려져 있다. 골격근내의 가변적인 혈류량, 근수축이나 난류성 혈류 등과 같은 물리적인 요인, 골격근내의 산성 환경, 젖산, 세포외 기질의 단백분해효소 억제인자 등이 골격근으로의 원격 전이를 억제하는 원인으로 제시되고 있다. 저자들은 최근 다발성 골격근 전이를 동반한 신장암(이행성 상피세포암) 1례를 경험하였기에 이를 보고하는 바이다.