집속형 초음파 장치용 압전 세라믹의 소결특성에 미치는 CIP 효과

노상훈,김부안,황건태 한국동력기계공학회 2023 동력시스템공학회지 Vol.27 No.2

It was molded using cold isostatic pressure and then sintered to examine the impact of molding pressure on the sintering shrinkage rate, compressive strength, and relative permittivity on cylindrical-shaped PZT ceramics. As a result, the sintering shrinkage rate decreases with increasing molding pressure. Moreover, PZT ceramics with extremely high compressive strength and relative permittivity might be made by utilizing cold isostatic pressure molding. In particular, sufficient strength was guaranteed for compressive strength without post-heat treatment. The ideal sintering parameters for the PZT ceramic powder employed in this experiment are thought to be a forming pressure of 300 MPa and a sintering period of one hour. 냉간 정수압 장치를 이용하여 성형 소결한 PZT 세라믹스에 대하여 성형 압력이 소결 수축률, 압축강도, 비유전율에 미치는 영향을 조사하였다. 냉간 정수압 장치의 성형 압력이 증가할수록 소결수축률은 감소하였다. 냉간 정수압에 의해 매우 높은 압축강도와 비유전율을 띠는 원통형 PZT 세라믹스를 제조할 수 있었는데, 특히 압축 강도는 소결이 끝난 후 추가적인 열처리를 하지 않아도 충분히높은 강도가 확보되었으며, 300 MPa의 성형압력과 1시간의 소결 시간이 가장 이상적인 소결 조건이었다.

시스템 종속 그래프에 기반한 프로그램 자르개의 구현

노상훈,신승철 한국정보과학회 프로그래밍언어연구회 2005 프로그래밍언어논문지 Vol.19 No.2

프로그램 자르기(Program Slicing)는 프로그램의 이해와 디버깅 등을 돕는 매우 유용한 도구로 알려져 있고 프로그램 분석에도 이를 도입하여 효과를 배가하는 시스템이 연구되어 왔다. 우리는 시스템 종속 그래프를 이용하는 프로그램 자르개를 구현하였는데 본 논문에서는 그래프의 적절한 표현방법과 잘라낸 정보(slice info)를 취급할 때 발생한 문제를 해결하는 방법을 설명한다. 또한 구현된 자르개가 소프트웨어 보안 문제의 하나인 정보흐름 보안성 검증에서 어떻게 응용될 수 있는지를 설명한다.

비부착텐던 PSC 격납건물에 대한 구조건전성시험 및 수치해석 I

노상훈,정래영,김성택,임상준,Noh, Sanghoon,Jung, Raeyoung,Kim, Sung-Taek,Lim, Sang-Jun 한국전산구조공학회 2015 한국전산구조공학회논문집 Vol.28 No.5

원자로 격납건물은 냉각재상실사고와 같이 내부의 과도한 압력이 유발되는 사고에 있어서도 방사성 물질이 외부로 누출되지 않도록 막는 최종의 방벽이다. 이러한 격납건물의 기능적 중요성에 기인하여, 건설 초기 구조건전성시험(SIT)을 수행한다. 신고리 3호기 SIT 시험 당시 계측된 변위를 예측하기 위한 초기 해석 모델은 일부 위치에서 실제 변위를 과소 평가하는 경향을 보임에 따라 이를 개선하고자 하는 연구가 수행되었다. 해당 연구의 결과를 I 편과 II 편의 논문으로 정리하였으며, 본 I 편에서는 초기 해석모델을 개선해가는 과정에서의 해석모델 구성 시의 주요 고려사항의 분석 및 예비해석 결과를 제시하고 있다. 우선적으로 콘크리트 자체의 해석요소(mesh) 구성과 라이너, 철근, 텐던 등의 요소간의 연결 설정이 중요함을 확인하였다. 또한, 다양한 예비해석의 결과를 통해 비부착식 텐던으로 시공된 구조물에서 덕트관에 의한 강성 저감 효과 및 덕트관을 사이에 둔 텐던과 콘크리트간의 밀착 여부에 따른 강성 영향을 적절히 고려하는 것이 중요함을 확인하였다. A reactor containment acts as a final barrier to prevent leakage of radioactive material due to the possible reactor accidents into external environment. Because of the functional importance of the containment building, the SIT(Structural Integrity Test) for containments shall be performed to evaluate the structural acceptability and demonstrate the quality of construction. An initial numerical analysis was performed to simulate the results obtained from the SIT for a prestressed concrete(PSC) structure. But the analysis results by the initial model expected smaller displacements than the measured ones by 30% at some locations. Accordingly, the research and development to improve the initial model to corelate the measured results of the SIT more properly have been performed. In this paper, the effects of the loss of concrete due to duct for tendons and the contact of duct and tendons in un-bonded tendon system are mainly evaluated based on the preliminary analysis results. In addition, the importances of the proper definition of mesh connectivity among structural elements of concrete, liner plates, rebars and tendons are discussed.

이하선에 발생한 양측성 Warthin씨 종양 치험례

노상훈,손형빈,정영진,홍인표 대한두개안면성형외과학회 2008 Archives of Craniofacial Surgery Vol.9 No.2

Warthin's tumor is a benign neoplasm that most frequently occurs in the parotid gland. Warthin's tumor shows a tendency of bilateral occurrence, but most of bilateral tumors occur at different time. It usually affects older man and grows slowly. Surgical excision is appropriate treatment for patients with Warthin's tumor and rarely recurs after removal. We report a rare case of bilateral Warthin's tumor which detected at the same time. A 54-year-old man had painless, slowly growing masses on the both mandibular angles. The masses were detected ten years ago. CT scan, ultrasonographic evaluation and fine needle biopsy was performed for preoperative diagnostic study. Superficial parotidectomy was done one after the other at ten-day intervals. After excision, histological examination revealed a mixture of ductal epithelium and a lymphoid stroma. The overlying surface of lymphoid tissue was covered with epithelial cells that was abundant of eosinophilic cytoplasm. Both masses were diagnosed as Warthin's tumor. Postoperatively, the patient did well and had no evidence of recurrence of tumor for 2 years follow-up period. Authors experienced a rare case of bilateral Warthin's tumor which detected at the same time. We recommend stepwise superficial parotidectomy at one or two-week intervals as treatment of bilateral Warthin's tumor.

Effects of Heat Treatments on Microstructures and Mechanical Properties of Dual Phase ODS Steels for High Temperature Strength

노상훈,최병권,한창희,강석훈,장진성,정용환,김태규 한국원자력학회 2013 Nuclear Engineering and Technology Vol.45 No.6

In the present study, the effects of various heat treatments on the microstructure and mechanical properties of dual phaseODS steels were investigated to enhance the high strength at elevated temperature. Dual phase ODS steels have been designedby the control of ferrite and austenite formers, i.e., Cr, W and Ni, C in Fe-based alloys. The ODS steels were fabricated bymechanical alloying and a hot isostatic pressing process. Heat treatments, including hot rolling-tempering and normalizingtemperingwith air- and furnace-cooling, were carefully carried out. It was revealed that the grain size and oxide distributionsof the ODS steels can be changed by heat treatment, which significantly affected the strengths at elevated temperature. Therefore, the high temperature strength of dual phase ODS steel can be enhanced by a proper heat treatment process with agood combination of ferrite grains, nano-oxide particles, and grain boundary sliding.

비부착텐던 PSC 격납건물에 대한 구조건전성시험 및 수치해석 II

노상훈,정래영,이병수,임상준,Noh, Sanghoon,Jung, Raeyoung,Lee, Byungsoo,Lim, Sang-Jun 한국전산구조공학회 2015 한국전산구조공학회논문집 Vol.28 No.5

원자로 격납건물은 냉각재상실사고와 같이 내부의 과도한 압력이 유발되는 사고에 있어서도 방사성 물질이 외부로 누출되지 않도록 막는 최종의 방벽이다. 이러한 격납건물의 기능적 중요성에 기인하여, 건설 초기 구조건전성시험(SIT)을 수행한다. 이러한 SIT거동을 가장 실제와 가깝게 예측하기 위한 해석 연구를 수행하였다. 해당 연구의 결과는 2편의 논문으로 정리되었는데, 본 논문은 그 중 II편으로 I편의 해석모델 구성 시의 주요 고려사항의 분석 및 예비해석 결과를 반영한 상세 해석 모델의 구성 과정 및 해석 결과를 제시하고 있다. 특히 비부착식 텐던으로 시공된 구조물에서 덕트관에 의한 강성 저감효과 및 덕트관을 사이에 둔 텐던과 콘크리트간의 밀착 여부에 따른 영향을 해석 시 최대한 고려하고자 하였다. 이러한 과정을 통해 구축된 해석 모델에 따른 변위과 신고리 3호기 SIT 측정변위를 비교한 결과, ASME CC-6000 기준을 충분히 만족시키는 결과가 나타남을 확인하였다. A reactor containment acts as a final barrier to prevent leakage of radioactive material due to the possible reactor accidents into external environment. Because of the functional importance of the containment building, the SIT(Structural Integrity Test) for containments shall be performed to evaluate the structural acceptability and demonstrate the quality of construction. In this paper, numerical analyses are presented, which simulate the results obtained from the SIT for a prestressed concrete(PSC) structure. A sophisticate structural analysis model is developed to simulate the structural behavior during the SIT properly based on various preliminary analysis results considering contact condition among structural elements. From the comparison of the analysis and test results based on the acceptance criteria of ASME CC-6000, it can be concluded that the construction quality of the containment has been well maintained and the acceptable performance of new design features has been verified.

두피에 발생한 피지선암 2례

노상훈,정영진,홍인표,손형빈,정영진 대한성형외과학회 2009 Archives of Plastic Surgery Vol.36 No.3

Purpose: Sebaceous carcinoma is a rare malignant tumor derived from the adnexal epithelium of sebaceous glands. This tumor usually occurs on the eyelids, but uncommonly it may occur on the extraocular sites. It is characterized by a tendency of local recurrence and occasional metastasis. Surgical excision is appropriate treatment for patients with sebaceous carcinoma. While this kind of case is rare, we report two cases of sebaceous carcinoma developed on scalp. Methods: Case 1 was a 69-year-old woman. She visited the hospital with a 1.5×2.5cm sized reddish yellow-colored, slowly growing mass on the left parietal scalp. The mass began at birth and started growing 5 years ago. Case 2 was a 67-year-old woman. She had 2.5×3.0cm sized yellow-colored mass on the right parietal scalp. It occurred at birth and started growing 3 years ago. And the masses had erythematous ulcer with sanguineous discharge. In the beginning, the masses were miliary nodule. Results: CT scan and fine needle biopsy were done. Case 1 and 2 were diagnosed as sebaceous carcinoma. Wide excision with safety margin of 10mm and split thickness skin graft was done. Histological examination revealed well demarcated, irregular, variable sized tumor lobules. Each lobule was composed of sebaceous and undifferentiated cells. Postoperatively, the patients did well and the lesion did not recur. Conclusion: Sebaceous carcinoma is an aggressive malignant tumor. It is often confused with other skin tumors. Authors experienced two rare cases of sebaceous carcinoma developed on scalp. We recommend early wide excision with enough safety margin as treatment of sebaceous carcinoma.

CDMA 시스템을 위한 SLSP 적응 배열 안테나

노상훈,구준모,김제우 한국통신학회 2001 한국통신학회 학술대회 및 강연회 Vol.2001 No.4

Evolution on Microstructures and Tensile Properties of 10Cr-1Mo ODS Steel with Different Lengths of Mechanical Alloying Process Times

노상훈,김태규,Noh, Sanghoon,Kim, Tae Kyu The Korean Powder MetallurgyMaterials Institute 2021 한국분말재료학회지 (KPMI) Vol.28 No.5

In this study, we investigate the effect of the duration of mechanical alloying on the microstructures and mechanical properties of ODS ferritic/martensitic steel. The Fe(bal.)-10Cr-1Mo pre-alloyed powder and Y₂O₃ powder are mechanically alloyed for the different mechanical alloying duration (0 to 40 h) and then constantly fabricated using a uniaxial hot pressing process. Upon increasing the mechanical alloying time, the average powder diameter and crystallite size increased dramatically. In the initial stages within 5 h of mechanical alloying, inhomogeneous grain morphology is observed along with coarsened carbide and oxide distributions; thus, precipitate phases are temporarily observed between the two powders because of insufficient collision energy to get fragmented. After 40 h of the MA process, however, fine martensitic grains and uniformly distributed oxide particles are observed. This led to a favorable tensile strength and elongation at room temperature and 650℃.

Y3Al5O12 첨가가 질화규소 세라믹스의 제조 및 그 기계적 특성에 미치는 영향

노상훈,김부안,문창권,정해용,서원찬,윤한기 한국해양공학회 2007 韓國海洋工學會誌 Vol.21 No.6

In the present work, silicon nitride was fabricated with Y3Al5O12 as a sintering additive and its mechanical properties were investigated. Silicon nitride with 3, 5, and 7 wt% of Y3Al5O12 was prepared and sintered by a Hot Pressing (HP) technique at 1750 and 1800℃ for 2 h. The process was performed under different process pressures of 30 and 45 MPa. Mechanical properties (density, strength, hardness, and fracture toughness) were investigated as a function of the Y3Al5O12content in Si3N4. Si3N4 -Y3Al5O12 ceramics showing similar mechanical properties compared with Si3N4-Y2O3-Al2O3 ceramics. But its high temperature strength was considerably higher than that of Si3N4-Y2O3-Al2O3 ceramics.1. 서 론 산업이 고도화되고 이용되는 부품소재가 더욱 가혹한 환경에 노출됨에 따라 기존의 금속이나 고분자소재보다 높은 기계적 특성을 지니는 구조세라믹스에 대한 요구가 증대되고 있다. 그러나 실제 응용에 있어서 구조세라믹스는 자체의 신뢰도와 취성 때문에 많은 제한이 있으며, 이를 극복하기 위해 가혹한 환경에서의 높은 강도와 파괴인성을 확보하는 것이 가장 중요한 과제로 대두되고 있다(Tsuge et al., 1975; Sanders and Mieskowski, 1985).대표적인 구조세라믹스인 질화규소는 강도, 내열성, 내열충격성, 내화학성, 내마모성 등이 매우 우수한 재료이다. 이러한 특성으로 자동차 엔진부품, 가스 터빈, 절삭 공구, 베어링, 펌프용 실링(Sealing)재로 산업전반에 걸쳐 활용되고 있다. 하지만 Si3N4는 소결 시 충분한 소결강도를 가지기 전에 분해할 뿐만 아니라, 난소결성이며 파괴인성 또한 낮은 것이 단점으로 지적되고 있다. 이러한 단점을 극복하기 위하여 일반적으로 질화규소는 Al2O3, Y2O3, MgO, ZrO2 등의 소결조제를 첨가하여