• 한국기계가공학회지
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• 제21권3호
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• pp.12-21
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• 2022

Directed energy deposition (DED) was adopted as a metal additive manufacturing method to develop a mold for the hot stamping process. The test piece was machined from Heatvar laminate material, and results were obtained through microstructure and defect observations, as well as hardness, tensile strength, and joint strength tests. 1) Spherical pores and irregular-shaped cavities were observed as lamination defects, and columnar dendrites formed in the structure, which tended to become coarse upon heat treatment. 2) The hardness of the heat-treated material (480HV) was slightly lower than that of the non-heat-treated material (500HV). 3) In the tensile test, the maximum tensile stress and strain of the heat-treated material were 1392 MPa and 15%, respectively, which were slightly higher than the values of 1381 MPa and 13%, respectively, for the non-heat-treated material. 4) In the case of the early final fracture in the tensile test, in most cases, pores or irregularly shaped cavities were observed at the fracture surface or near the surface. 5) In the joint strength test, most of the specimens finally fractured in the laminated metal area, and the fracture surface was intragranular. In addition, dimples formed over the entire area on the fracture surface of the fractured specimen after sufficient elongation.

• 한국광물학회지
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• 제1권2호
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• pp.117-130
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• 1988

감포지역(甘浦地域)에서 산출(産出)되는 성질(性質)이 다른 시료(試料)들을 전자현미경(電子顯微鏡)에 의하여 그 형태적(形態的) 특징(特徵)을 관찰한 결과 몬모릴로나이트는 화산성물질(火山性物質) 즉 응회암기원(凝灰岩起源)임을 지시(指示)한다. 주사전자현미경(走査電子顯微鏡)에 의한 몬모릴로나이트의 형태적특징(形態的特徵)은 결정성장(結晶成長)에 필요한 가용공간(可用空間)의 유무(有無)에 따라 크게 영향을 받는 것으로 보이며, 가용공간(可用空間)이 충분한 경우엔 전형적(典型的)인 honeycomb 구조를 이루며 그와 반대인 경우에는 조밀하게 패킹된 판상(板狀)의 집합체(集合體)로 산출(産出)되는 경향을 보인다. 투과전자현미경(透過電子顯微鏡)으로 관찰된 결정형(結晶型)의 종류는 동일(同一)한 시료내에서 여러 가지가 관찰되나 불규칙한 엽상(葉狀)의 집합체(集合體)가 가장 우세하게 산출(産出)되며 판상(板狀)의 결정형(結晶型)이 흔히 관찰된다. 일반적으로 본 연구지역 중 죽전리(竹田里)의 효동리화산암류(孝洞里火山岩類)에서 산출되는 시료들보다 용동리(龍洞里)의 용동리응회암내(龍洞里凝灰岩內)에 배태(胚胎)된 시료에서 상대적(相對的)으로 판상(板狀)의 결정형이 우세하다.

• Parasites, Hosts and Diseases
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• 제33권4호
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• pp.395-398
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• 1995

강원도 홍천에 거주하는 56세 구부가 갑자기 우상부 복통 고열 오한을 주소로 내원하였고 복 꾸 초음파검사와 콤퓨터단층촬영 결과 2-3 cm 직경의 불규칙한 꼴의 동공이 간 우엽에서 여러개 관찰되었다. 간생검상 샤르코-라이덴 결정을 포함한 심한 중심성 괴사 주위로 조직구. 호산구등 염 증세포가 침윤되어 주위 조직과 명확히 구분되었다. 효소면역측정법을 이총한 간질 특이 항체 혈청 걸사에서 양성이었다. 간 병변은 프라지관텔 투약 6개웍 후에 모두 사라졌으나. 특이 항체가와 호산구 증가는 투약 6개월 16개월 후에도 정상화 되지 않았다. 방사선학적 소견 조직병리학 소견 및 혈청학 검사 결과를 종합할 때. 초기 침습성 간질증으로 진단하였으며 프라지콴텔에 의하여 치료되지 않은 예이었다.

• Restorative Dentistry and Endodontics
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• 제25권2호
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• pp.243-253
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• 2000

The purpose of this in vitro study was to evaluate dentin bonding by two different dentin bonding systems(DBS) using acetone based primer or adhesive [All Bond 2(AB2), One Step(OS)] when they were applied by wet or dry bonding technique. Morphology of resin-dentin interface and hybrid layer thickness(HLT) were investigated using Confocal Laser Scanning Microscope(CLSM) and compared to shear bond strength(SBS). 72 extracted sound human molars were randomly divided into 4 groups of 18 teeth each - Group 1.(AW); AB2 by wet bonding. Group 2(AD); AB2 by dry bonding. Group 3.(OW); OS by wet bonding, Group 4.(OD); OS by dry bonding. In 6 teeth of each group, notch-shaped class V cavities(depth 2mm) were prepared on buccal and lingual surface at the cementoenamel juction(12 cavities per group). To obtain color contrast in CLSM observation, bonding resins of each DBS were mixed with rhodamine B and primer of AB2 was mixed with sodium fluorescein. Prepared teeth of each group were treated with AB2, OS, respectively according to the manufacturer's instructions except for dentin surface moisture treatment after acid etching. In group 1 and 3, after acid etching, excess water was removed with wet tissue(Kimwipes), leaving consistently shiny, visibly hydrated dentin surface. In group 2 and 4, dentin surface was dried for 10 seconds at 1 inch distance. The treated teeth were then packed with composite resin(${\AE}$litefil) and light-cured. 12 microscopic samples($60{\sim}80{\mu}m$ thickness) of each group were obtained after longitudinal section and grinding(Exakt cutting and grinding system). Morphological investigation of resin-dentin interface and HLT measurement using CLSM were done. For measurement of SBS, remaining 12 teeth of each group were flattened occlusally to remove all enamel and grinded to 500 grit SiC(Pedemet Specimen Preparation Equipment). After applying DBS on the exposed dentin surface, composite resin was applied in the shape of cylinder, which has 5mm diameter, 1.5mm thickness, and light cured. SBS was measured using Instron with a crosshead speed of 0.5mm/min. It was concluded as follows, 1. HLT of AW(mean: $2.59{\mu}m$) was thicker than any other group, and followed by AD, OW, OD in descending order(mean; 2.37, 2.28, $1.92{\mu}m$). Only OD had statistically significant differences(p<0.05) to AW and AD. 2. There were intimate contact of resin and dentin at the interface in wet bonding groups, but gaps or irregular interfaces were observed in dry bonding groups. 3. The length, diameter, density of resin tags were various even in the same group without significant differences between groups and lots of adhesive lateral branches were observed. 4. There were no statistically significant difference of SBS between AB2 and OS, but SBS of wet bonding groups were significantly higher(p<0.05) than dry bonding groups. 5. There were no consistent relationships between HLT and SBS.

• Archives of Reconstructive Microsurgery
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• 제7권1호
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• pp.62-67
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• 1998

전북대학교병원 정형외과에서 1994년 6월부터 1998년 3월까지 하퇴부 원위 1/3 및 족부에 시행하였던 박근 유리조직 이식술 12례에 대하여 최소 6개월부터 최고 4년 9개월까지 추시하여 다음과 같은 결과를 얻었다. 1. 하퇴부 원위 1/3의 손상원인은 개방성 골절에 의한 뼈 및 연부조직노출이 4례(33.3%)였으며, 골절수술후 연부조직 괴사로 인한 2차 뼈 및 내고정물노출이 2례(16.7%)였고, 족부의 손상원인은 압궤손상 5례(41.7%), 골절치료시 발뒤꿈치의 압박괴사 1례(8.3%)였다. 2. 수여혈관은 하퇴부 원위 1/3에서는 전경골 동맥이 4례, 비골동맥과 족배동맥이 각각 1례였으며, 족부의 수여혈관은 족배동맥이 4례, 후 경골동맥이 2례였다. 수여정맥은 2개를 봉합함을 원칙으로 하였으나 하퇴부 원위 1/3에서 총 6례중 3례, 족부에서도 총 6례중 3례에서만 2개의 수여정맥 봉합술이 가능하였다. 3. 총 12례중 11례(91.7%)에서 술후 3주까지 관류(perfusion)가 가능하여 성공하였으며, 피부 이식술은 술 후 평균 22일만에 시행하였고, 재활운동은 술후 평균 32일만에 가능하였다.