• 소성∙가공
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• 제9권5호
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• pp.463-468
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• 2000

An experimental study has been performed to investigate the forming characteristics of pre-coated metals(PCMs) widely used in domestic appliances through Erichsen tests and deep drawing tests. Erichsen tests are performed to find out the forming limits of seven pre-coated metals in normal conditions. Rectangular deep-drawing tests are carried out to know the effects of die materials and blank metals on forming loads and surface defects of final PCM products. In the deep-drawing test, four die materials ［STD11(TiCN), STD11, STD11(TD), AMPCO] are used. In the Erichsen test, the forming limits of PCMs are obtained from flaking or crack of pre-coated films and lower than those of base metals. In respect of surface roughness and forming load, STD11(TD) and AMPCO materials are superior to my other die-materials used in the deep-drawing test.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1992년도 추계학술대회 논문집
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• pp.96-100
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• 1992

각종 금형 중 사출금형과 프레스 금형이 전체의 80~90%를 차지하고 있으며, 이들 금형을 가공할 때 방전가공이 주로 이용되되 있다. 금형재료 중에서 합금공구강(STD 11)은 열처리하였을 때 경도가 매우 커서 프레스 금형의 다이오와 펀치 등에 널리 사용되고 있다. 이것은 Wire-EDM 이나 Die Sinking EMD으로 가공하고 있다. 따라서 본 연구에서 프레스 금형의 다이와 펀치 등에 널리 사용되는 열처리된 STD11을 사용하여 가공 제특성에 영향을 주는 가공조건, 즉 방전전류펄스폭 및 방전전류파 고치를 변화시켜 이에 따른 공작물 가공량, 전극소모비, 표면조도, 가공단면의 열변질층 및 경도 변화 등 방전가공비의 성상을 조사하여 STD11의 최적의 방전가공조건을 찾고자 하는 것을 목적으로 하였다.

• 한국진공학회지
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• 제3권4호
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• pp.449-456
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• 1994

산업용 주요 냉간금형 소재인 STD 11 강에 질소이온주입하여 이온조입조거에 따른 질화물형성 거동, 경도 및 내마모성 변화에 관해 연구하였다. XRD분석결과 90keV 에너지로 5$\times$1017 ions/cm2 조사 량 이상에서 Fe2N형태의 질화물이 형성되었으며 3$\times$1016 ions/cm2 범위의 모든 조사량에서 경도 및 조 사량에서 경도 및 내마모성 향상효과를 얻었다. Al2O3와의 ball-on-disc 마모거동 분석결과 STD 11모재 는 응착마모와 산화마모의 혼합형태로 마모되는 반면 질소이온주입한 경우 산화마모 경향이 강하게 나 타났다.

• 성인간호학회지
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• 제25권1호
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• pp.83-94
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• 2013

Purpose: The purpose of the study was to examine the sexual behavior and awareness of sexually transmitted diseases (STD) among the elderly. Methods: Subjects were 599 elderly living in a metropolitan area who completed a structured questionnaire. Data collection was from September 6, 2011 to January 17, 2012. The data were analyzed by using percentage and ${\chi}^2$-test. Results: Approximately 25% of the subjects reported a sexual life. Age, gender, education, family type, presence and health of spouse, health state of the subject, past occupation, dwelling pattern, and economic state made statistically significant difference in sexual behavior. Fifty five percent of the respondents reported no knowledge of STD. Factors such as age, gender, education, presence of spouse, and past occupation were statistically significant in terms of awareness of STD. Conclusion: Age, education, and presence of spouse should be factored in to understand the sexuality of the elderly as well as to develop sexuality counseling programs that provide adequate information for each individual.

• 대한화학회지
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• 제62권2호
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• pp.159-165
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• 2018

For the first time, the spot the differences (STD) game was employed in the teaching of basic organic chemistry course. Three sets of paired pictures associated with selected topics in organic chemistry were presented to the students and they were required to spot the differences between the two pictures. Based on the students' pre and post self-assessment, the STD game resulted in several positive learning outcomes as indicated in the students' reflective writing, including knowledge recall, deeper understanding of a subject, enhanced analytical skill, motivation and fun-filled learning, learning from peers and self-empowerment in learning. The STD game is a desirable teaching and learning tool, as learning in an entertaining and interactive way is highly sought after in today's classroom, especially to novice students. In the future, the STD game can be modified and implemented to cater the needs of different courses and topics.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 추계학술대회 논문집
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• pp.329-334
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• 2002

High-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut, feed rate, spindle revolution and cutting force are control factors. The effect of the control factors on machining accuracy is discussed for the results of surface roughness and machining error in Z-direction for the high speed machining of STD11.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 춘계학술발표대회
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• pp.7-9
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• 2013

유도무기는 점검장비와 MIL-STD-1553B 통신 시 많은 양의 데이터를 처리하고, 전달 받은 데이터에 대해 정확성과 빠른 응답성을 요구하기 때문에 점검장비에서 데이터를 실시간으로 처리하고 판단하는 것이 매우 중요하다. 따라서 본 논문에서는 이러한 문제를 해결하기 위해 기존에 개발된 실시간 이식 커널을 이용하여 미들웨어에서 MIL-STD-1553B 통신에 요구되는 주기적인 통신의 마감시간을 보장하도록 설계 및 구현하였다.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 1998년도 학술대회지 vol.1
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• pp.149-161
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• 1998

본고에서는 CALS/EC 개발전략의 일환으로 소프트웨어 프로세스 수명주기 중 국제표준인 ISO/IEC 12207과 현재 미 국가 표준으로 채택된 IEEE/EIA 12207에 관하여 고찰해보고, ISO/IEC 12207의 모체라 할 수 있는 미국방성의 소프트웨어 개발 프로세스인 MIL-STD-498과 비교분석 하였다. 또한 현재 국내 국방분야에서 적용하고 있는 소프트웨어 수명주기 프로세스에 조명해보았다. MIL-STD-498을 근간으로 한 국방분야의 소프트웨어 수명주기 프로세스는 그 내용이 아직도 반복개발의 개념이나 프로젝트 특성에 따른 프로세스의 관리 등 새로운 개발 철학들을 수용하고 있지 못한 실정이다. 본 연구에서는 현 국방분야의 소프트웨어 수명주기 프로세스의 개선안으로 프로세스를 재정립한 후, 점진적 개발접근방법, 진화적 개발접근 방법의 수용과 프로세스의 특성에 따라 프로세스들을 선택. 적용할 수 있는 MIL-STD-498을 기반으로 한 테일러링 방법을 제시하였다.

• 한국해양공학회지
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• 제31권2호
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• pp.81-90
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• 2017

The 1MW OTEC (Ocean Thermal Energy Conversion) platform was designed for application in equatorial seas. In this study, the OTEC platform was investigated using numerical and experimental methods. An octagon-shaped OTEC platform was investigated using the Ocean Engineering Basin of KRISO. These experiments included various tests of regular waves, irregular waves and irregular waves with current (wave+current). The responses of the platform in regular waves showed good agreement between the numerical and experimental results, including the motion RAO, wave run up, and mean drift force. The peak period of heave and pitch motions were observed around 0.5 rad/s, and the effect of the total reflection was found under short wave conditions. The standard deviation (STD) of the platform motion was checked in irregular waves of equatorial and Hawaiian seas. The STD of the pitch was less than $4^{\circ}$ different from the operability requirement under equatorial conditions and the surge STD of the wave frequency showed good agreement between the numerical and experimental results. The STD values of the surge and pitch were increased 66.6% and 92.8% by the current effects in irregular waves, but the pitch STD was less than $4^{\circ}$ under equatorial conditions. This study showed that the STD of the surge was affected by spring effects. Thus, the watch circle of the platform and tension of the mooring lines must be evaluated for a specific design in the future.

• 대한금속재료학회지
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• 제46권12호
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• pp.800-808
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• 2008

Heat treatment is an important step for tool manufacture, but unavoidably generates dimensional distortion. This study investigated the continuous dimensional change and the anisotropic behavior of STD11 tool steel during austenitizing and tempering heat treatment especially using quenching dilatometer. Dilatometric results represented that the dimensional change along longitudinal direction was larger than that along transverse direction. Anisotropic phase transformation strain was produced in forged STD11 tool steel during heat treatment. Anisotropic dimensional change increased with increasing austenitizing temperature. After tempering, anisotropic distortion was partially reduced. FactSage thermodynamic equilibrium phase simulation and microstructural observation (FE-SEM, TEM) showed that large ($7{\sim}80{\mu}m$) elongated $M_7C_3$ carbides could be formed along rolling direction. The resolution of elongated carbides during austenitizing was found to be related with the change of martensite transformation temperature after heat treatment. Anisotropic size change of STD11 tool steel was mainly attributed to large elongated carbides produced during rolling process. Using dilatometric and metallographic examination, the possible mechanism of the anisotropic size change was also discussed.