• 한국세라믹학회지
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• 제35권2호
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• pp.137-144
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• 1998

고온초전도체 61심 Bi-2223 선재간의 초전도 접합부위를 화학적 부식 및 열적· 기계적 반복 공정에 의하여 제조하였다. 초전도 선재 테이프의 은 피복재 한쪽 표면을 초전도체와 반응하지 않는 부식액(NH4OH:H2O2=1:1)으로 화학적으로 제거한 다음, 두 시편을 일출가압 성형하여 접합시편을 제조하였고 일련의 서로 다른 열적· 기계적 처리를 거쳐 접합부의 물성 및 미세구조를 분석하였다. 접합부를 따라 임계전류(Ic) 변화와 전류전압 곡선의 특성을 측정하기 위하여 여러 단자를 접합부 주위에 설치하여 부위별 I~V 특성을 측정한 결과 단심선재에 비하여 다심선재에서 선재 전체의 통전 능력을 좌우하는 천이구간의 임계전류값이 높았다. 그러나 단심에 비해 다심선재는 천이급속도를 나타내는 n값이 다심선재내 각각의 초전도 core들의 상호작용에 의하여 낮은 값을 나타내었다. 접합부의 임계전류 통전성은 반복적인 가압성형 공정과 서냉반응 열처리 공정에 의하여 향상되었다.

• Composites Research
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• 제20권5호
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• pp.26-33
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• 2007

본 논문에서는 풀아웃 하중과 전단하중을 받는 복합재 샌드위치 인써트 조인트의 강도 특성을 실험으로 연구하였다. 샌드위치의 면재는 탄소 평직, 심재는 노멕스 하니콤, 접착제는 FM73을 사용하여 동시성형으로 제작하였다. 코어의 높이와 밀도, 면재의 두께, 하중의 형태를 달리하여 10종류, 총 75개의 인써트 조인트에 대한 실험을 수행하였다. 실험 결과, 풀아웃 하중에서는 코어의 높이와 밀도가 모두 파손하중에 영향을 미치지만 밀도의 영향이 상대적으로 더 크게 나타났다. 전단하중의 경우 면재의 두께가 파손하중에 결정적인 영향을 미치는 반면, 코어의 높이는 큰 영향을 미치지 않는 것으로 나타났다. 동일한 치수의 조인트에서도, 포팅된 쎌의 수에 따라 파손하중은 달라지며, 특히 풀아웃 하중에서 그러한 특성이 현저하게 나타났다.

• Steel and Composite Structures
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• 제47권1호
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• pp.19-36
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• 2023

An experimental study of eleven PVC-FRP Confined Concrete (PFCC) column-Reinforced Concrete (RC) beam joints reinforced with Core Steel Tube (CST) under axial compression is carried out. All specimens are designed in accordance with the principle of "weak column and strong joint". The influences of FRP strips spacing, length and steel ratio of CST, height and stirrup ratio of joint on mechanical behavior are investigated. As the design anticipated, all specimens are destroyed by column failure. The failure mode of PFCC column-RC beam joint reinforced with CST is the yielding of longitudinal steel bars, CST and stirrups of column as well as the fracture of FRP strips and PVC tube. The ultimate bearing capacity decreases as FRP strips spacing or joint height increases. The effects of other three studied parameters on ultimate bearing capacity are not obvious. The strain development rules of longitudinal steel bars, PVC tube, FRP strips, column stirrups and CST are revealed. The effects of various studied parameters on stiffness are also examined. Additionally, an influence coefficient of joint height is introduced based on the regression analysis of test data, a theoretical formula for predicting bearing capacity is proposed and it agrees well with test data.

• Journal of Welding and Joining
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• 제29권2호
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• pp.72-79
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• 2011

The scope of this investigation is to evaluate the effect of joining parameters on the microstructural features and mechanical properties of dissimilar aluminum alloys, 1mm-thickness fixing AA6K31 at the top position and fixing AA5J32 at the bottom position. The friction stir lap welds were studied under various welding conditions, rotation speed of 1000, 1250, 1500rpm and welding speed of 100, 300, 500, 700mm/min, respectively. Mechanical test has been investigated in terms of tensile shear test and hardness test. The results showed that three type nugget shapes such as onion ring, zigzag type, hooking with the void, have been observed with revolutionary pitch. All welding conditions fractured at the HAZ of top plate, A6K31 and also the strength compare with base metal of lap joints were low efficiency, 52~63%. The thickness of fractured position was decreased with the lower heat input conditions. The relationships were excellent due to linear between the effective thickness of fractured position and peak load. The fractured position was the interface between joint area and not joint area. Also the strength efficiency compared with base metal was lower than decreasing rate of thickness because the hardness was decreased at fractured position due to softened material.

• Asian Journal of Innovation and Policy
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• 제4권2호
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• pp.178-199
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• 2015

This study provides a background on the growth of Indian automobile industry under different regulatory regimes. It is observed that the international joint ventures have played a key role in the growth of the sector. The study further examines the motives for forming IJVs in the auto component sector and also identifies the criteria for choosing the joint venture partner to mitigate conflicts. These two specific attributes form the core towards transfer of technology, promoting innovation and also act as a catalyst for adopting and choosing appropriate technology. The study brings out the relationship between motives, partner selection criteria and performance of the IJVs. Results indicate that firms gave maximum importance to technological skills, quality control measures and proprietary knowledge in selecting IJV partners. It is also observed that the motives affect the partner selection criteria in terms of skill and resources needed from the partner.

• 한국지반공학회논문집
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• 제18권4호
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• pp.229-238
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• 2002

본 연구에서는 절리면 거칠기를 정량적으로 산출하기 위하여 표면 거칠기 계수, Rs를 이용한 측정방법을 제안하고, 이를 바탕으로 절리면 거칠기가 절리면 전단강도에 미치는 영향을 제시하였다. 제시된 Rs를 이용하여 새로운 절리면 전단강도 모델을 제안하였다. 연구 결과, 표면 거칠기 계수인 Rs는 암반의 절리면 거칠기를 정량적으로 표현할 수 있는 유용한 방법이 될 수 있음을 알 수 있었다. Rs에 의한 암코아 규모의 절리면 거칠기 측정에는 최대 측정간격으로 2mm, 최소 측정 길이로 5cm가 적당하나, 이를 대규모의 현장 절리면에 확대 적용하기 위해서는 변동규모(scale of fluctuation), $\delta_u$를 도입하여야 한다. 절리면 거칠기가 작은 경우, 전단강도는 절리면에서의 미끄러짐으로 유발되었으나, 거친 절리면에서의 전단강도는 거칠기의 일부분이 파괴됨으로 인하여 발생됨을 알 수 있었다.

• 한국공간구조학회논문집
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• 제15권4호
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• pp.49-56
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• 2015

The roof grid of single-layer space frame structure, for Energy Core of Incheon Airport Second Terminal, is very simple and aesthetic, but it is apt to buckle under external force because of mild curvature and complex shape. The object of this study is to estimate the stability of single-layer space frame structures for Energy Core of Incheon Airport Second Terminal with the analytical conditions of structural design. The results show that the buckling load of model(pin-pin, uniform load, rigid joint), that is, the most similar model to the analytical conditions of structural design. was $10.7kN/m^2$.

• 국제물리치료학회지
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• 제11권3호
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• pp.2113-2118
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• 2020

Background: Patients with stroke have core muscle weakness and limited rib cage movement, resulting in restrictive lung disease. Objectives: To examine the comparison of effects of rib cage joint mobilization combined with diaphragmatic breathing exercise and diaphragmatic breathing exercise on the pulmonary function and chest circumference in patients with stroke. Design: A cluster randomized controlled trial. Methods: Twenty-four patients were randomly assigned to an experimental group (rib cage joint mobilization combined with diaphragmatic breathing exercise group) and control group (diaphragmatic breathing exercise group). Patients in the experimental group underwent rib cage joint mobilization for 15 min and diaphragmatic breathing exercise for 15 min. The control group underwent diaphragmatic breathing exercise for 30 min. Both groups underwent exercise thrice a week for 4 weeks. The pulmonary function and chest circumference were measured using the MicroLab spirometer and a tape measure, respectively. Results: After the intervention, the pulmonary function and chest circumference significantly improved in both groups. These improvements were significantly higher in the experimental group than those in the control group. Conclusion: Rib cage joint mobilization combined with diaphragmatic breathing exercise improves pulmonary function and chest circumference in patients with stroke.

• 시스템엔지니어링학술지
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• 제15권2호
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• pp.98-107
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• 2019

The defense system development process is a process of developing various systems that perform functions in various functional areas such as battlefield awareness, command control, force application, and logistical support. In other words, the defense system development process is a process of developing many systems simultaneously in various functional areas. Various systems developed through this process should be interoperable so that they can be integrated and operated in a joint warfighting environment. To successfully implement this, the US Department of Defense uses the Joint Capability Integrated Development System(JCIDS) for the defense system development, and within this JCIDS processes the Capability Based Assessment(CBA) methodology as its core technology. This CBA methodology transforms the mission activity requirements to functional capability requirements logically and transforms the functional capability requirements to system requirements logically also. Smart City is a city that improves the convenience and quality of life of the citizen by integrates various systems that perform various functions of the city and smarties various functional systems with smart services by using IT technology. In other words, defense system development and smart city development have a common feature of the process of developing many systems simultaneously in various functional areas. In order to address the problem of having to develop many systems simultaneously in each functional area, it is important to logically transform the various mission scenarios into functions and logically transform the functions into systems. Therefore, a joint capability integrated development system and its core methodology, Capability Based Assessment(CBA), can be applied to smart city development. This paper proposes a method for performing a smart city concept design method using the capability based evaluation (CBA) method.

• Annals of Clinical Neurophysiology
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• 제8권1호
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• pp.23-28
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• 2006

Background: central core disease is one of the non-progressive benign congenital myopathies characterized by the presence of cores in muscle fibers, which was originally described by Shy and Magee (1956). We describe clinical charcteristics of central core disease in a Korean family manifested by autosomal dominant pattern through three generations. Methods: Clinical, serologic, and electrophysiologic profiles were evaluated in eleven members among 22 family members through three generations. Results: Six family members were symptomatic and five were non-symptomatic. Instead of proximal muscle weakness, musculoskeletal manifestations including non-specific joint pain and stiff sense were the most frequent symptoms. Muscle biopsy performed in two symptomatic patients revealed that type I fiber showed central halo, which is charactreristics of central core disease. No remarkable findings were present in serologic study including CPK level and electromyographic findings suggesting myopathic pattern were only present in two patients among 11 symptomatic group. Conclusions: In evaluating non-specific musculoskeletal complaints from the familial members showing genetic trait, central core disease should be considered to one of the possible diagnosis.