• 열처리공학회지
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• 제14권2호
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• pp.110-117
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• 2001

Artificial aging was performed to simulate the microstructural degradation in 2.25CrMo steel arising from long time exposure at $540^{\circ}C$. It was found that the carbides became coarser and spheroidized as aging time increased. An attempt was made to evaluate the microstructural degradation in artificially aging heat treated 2.25CrMo steel by the ultrasonic attenuation and velocity measurements. Ultrasonic velocity was found essentially insensitive to the microstructural changes resulting from aging heat treatment. However, the ultrasonic attenuation was observed to increase with increasing aging time. Also, it was noticed that the change of ultrasonic attenuation with aging time was more sensitive at high frequency regions.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.162-162
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• 2003

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1998년도 추계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.26-27
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• 1998

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 1995년도 특별강연 및 추계학술발표 개요집
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• pp.201-203
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• 1995

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2002년도 추계학술강연 및 발표대회
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• pp.19-19
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• 2002

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2001년도 추계학술발표대회 개요집
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• pp.233-235
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• 2001

• BMB Reports
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• 제51권9호
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• pp.427-428
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• 2018

Based on the piling reports of disruptions in the thalamus of patients with schizophrenia, the alteration in the thalamo-cortical system has been regarded as the core pathophysiology. As the thalamus is composed of distinctive nuclei with different cytoarchitecture and cortical connections, nuclei specific investigations have been actively conducted in post-mortem studies. In addition, the importance of early changes has been highlighted, which in turn has led to investigations of the thalamo-cortical system using non-invasive neuroimaging methods. From this perspective, the early structural changes in the thalamo-cortical system, such as the thalamo-cortical connection and nuclei specific microstructural changes (which are coherent with findings from post-mortem methods) will be briefly discussed. The main findings, which are the reduced thalamo-prefrontal connection and reduced microstructural complexity in the higher-order nuclei detected in first-episode psychosis patients, suggest the occurrence of early alterations within and between the communication hub of the brain and cortex. These findings suggest not only directions for further studies for unveiling the thalamo-cortical system related pathophysiology, but also the possibility of using the reduced microstructural complexity in the higher order nucleus as a biomarker for schizophrenia.

• Applied Microscopy
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• 제45권1호
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• pp.32-36
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• 2015

The microstructural features of FeCoCrNi, FeCoCrNiAl and FeCoCrNiSix (x=0, 5, 10, 15, 20) alloys have been investigated in the present study. The microstructure of FeCoCrNi alloy changes dramatically with equiatomic addition of Al. The fcc irregular shaped grain structure in the as-cast FeCoCrNi alloy changes into the bcc interconnected structure with phase separation of Al-Ni rich and Cr-Fe rich phases in the as-cast FeCoCrNiAl alloy. The microstructure of FeCoCrNi alloy changes with the addition of Si. With increasing the amount of Si, the fcc structure of the grains is maintained, but new phase containing higher amount of Si forms at the grain boundary. As the amount of Si increases, the fraction the Si-rich grain boundary phase increases.

• 한국의류학회지
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• 제13권1호
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• pp.43-47
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• 1989

The microstructural changes of nylon 6 UDY, POY and FDY were compared after free-annealing through crystallinity, birefringence, and melting behavior analyses. Free-annealing was done at various temperatures $(120^{\circ}C\;,140^{\circ}C,\;160^{\circ}C,\;180^{\circ}C,\;200^{\circ}C)$ and times (15 min., 30 min., 60 min.) using vaccum oven. Crystallinity was measured by the density gradient column technique and birefringence was measured using a Nikon polarizing microscope with a quartz wedge and Senarmont compensator. Melting behavior was investigated on the basis of DSC melting corves. Crystallinites of specimens increased as the treatment temperature and time increased. Birefringence of UDY increased after annealing and increased as the treatment temperature increased. On the other hand, those of POY and FDY decreased after annealing. Especially, the changes of crystallinity and birefringence of treated POY were particularly lower than those of treated UDY and FDY. Melting peaks of untreated UDY, POY and FDY were different in the position and the shape, but little change was seen in melting peaks in spite of increasing the annealing temperature and time. UDY and FDY showed single melting peaks in all the specimens. But POY showed double melting peaks, which means the coexistences of crystals with different thermal properties.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.71-77
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• 2008

Microstructural changes may arise due to the particle vanishing, fluid diffusion, heating, etc. This study focuses on the changes in small-strain shear stiffness in k0 loading produced by local straining in particular system made of sand-salt mixtures. Local strains were induced by dissolution of salt particles. Experiments were carried out in a conventional oedometer cell equipped with bender elements. Axial displacement and shear wave signals are recorded at each loading stage and during saturation process. Experimental data showed that microstructural changes due to particle vanishing were clearly captured by using shear wave measurement. Saturation of sand-salt mixture at a larger axial stress did not always create a more condense soil at the end of loading stage. Sand-salt mixture is useful for laboratory test on controlled artificial specimen.