• 건축구조
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• v.17 no.1
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• pp.78-83
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• 2010

포스트텐션(Post-Tension, PT) 공법은 일반적으로 텐던(tendon)으로 알려진 고강도 강선 또는 봉을 이용하여 콘크리트 또는 다른 재료를 보강하는 방법으로 많은 경우 건설현장의 제약과 건축적인 요구에 의해 다른 공법으로 해결이 불가능한 경우에 대해 대안으로 사용되어 온 공법이다. 또한 포스트텐션 시스템은 조립과 설치에 특수한 지식과 경험이 필요하였다. 그러나 최근 건설시장은 신소재와 신공법의 발달과 함께 친환경 및 경제성에 대한 요구가 증가함에 따라 장스팬 및 층고절감이 가능한 포스트텐션 공법을 일반 건축물에 적용하는 사례가 점차 늘어나는 추세에 있다. 따라서 본 지에서는 3회에 걸쳐 포스트텐션 공법과 설계 및 시공사례 등을 소개하고자 한다. 1. 포스트텐션 공법 소개 2. 포스트텐션 공법의 경제성 비교 3. 포스트텐션공법의 설계사례와 설계시 고려사항

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1539-1542
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• 2005

Self-assembled monolayers (SAMs) formed by the adsorption of alkanethiols, $HS(CH_2)_nX$, where X is an organic functional group, onto gold surfaces have attracted widespread interest as templates for the fabrication of molecular and biomolecular microstructures. Previously photopatterning has been thought of as being restricted to the micron scale, because of the wellknown diffraction limit. So, we have explored a novel approach to nanofabrication by utilizing a femtosecond laser coupled to a near-field scanning optical microscope (NSOM).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1164-1167
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• 2005

This paper is about the carbon nanotube(CNT) samples called as CNT cartridges. The CNT cartridges are useful to make it better to fabricate the nano-sized devices like nanoprobes and nanotweezers through physical attachment. To make these cartridges, we need to align CNTs and to purify them from raw material. There is a variety of methods to align 1-dimensional nanostructures like nanotubes and nanowires. In this review, we mainly focused on the methods using electric field. And we will introduce various researches in relation to the CNT cartridges and the fabrication methods using the CNT cartridges and nanomanipulation techniques.

• Journal of Welding and Joining
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• v.16 no.6
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• pp.97-103
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• 1998

The bracket tilt among automobile parts is weld parts which construct the column assembly bracket tilt of equipments and accurate dimension after welding is more essential than weldment strength. By the way, it is insufficient that systematic study about this parts which have an importance on welding deformation. The reason is that welding deformation is complex problem with shape, size, material of parts and welding sequence, conditions etc. For reduction and removal of welding deformation, therefore, it is necessary that the security of welding deformation data and systematic examination about equipment, costs, work environment, manufacturing process etc. It is all the better that the prediction of welding deformation using simulation of welding process by FEA is supplemented. In this study, the countermeasure for this welding deformation of bracket tilt is brought up through experimental inspection before the choice of the optimum welding conditions with minimum welding deformation by simulation of welding process.

• Journal of the Korean Professional Engineers Association
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• v.22 no.3
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• pp.5-13
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• 1989

A major problem of stopwatch time study is how to do for the accurate and consistent performance rating, which is one of the critical variables to determine the accuracy of work measurement and should be still dependent upon time observer's judgement. Therefore the time observer's ability for the performance rating is very important, and must be improved by correct training method and procedure. This paper developed a new benchmark and benchmark-observation method for the effective performance rating training of assembling and machining operations. The trainees' ability in the accuracy and consistency of the performance rating ,improved significantly after being trained by subject method. The percentage improvement in rating accuracy and consistency values was 34.7% and 49% respectively. In addition, benchmark-practice method for the performance rating training is not significant, so it is proofed that the skill of a certain operation is not important for the improvement of the rating ability.

• Electronics and Telecommunications Trends
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• v.32 no.2
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• pp.29-36
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• 2017

본고에서는 바이오 기술(BT: Bio Technology)의 주요 소재인 DNA(DeoxyriboNucleic Acid, 디옥시리보핵산)를 정보기술(IT: Information Technology)과 나노 기술(NT: Nano Technology)에 적용한 세 가지 DNA 응용 기술 동향에 대해 소개하였다. 먼저 1958년 프랜시스 크릭(Francis Crick)이 주장한 센트럴 도그마(Central Dogma)의 출발점인 DNA의 구조와 기능에 대해 최대한 자세히 소개하였고, DNA의 염기 서열 방식을 이용한 DNA 저장장치에 관해 설명하였다. 그다음 장에서는 DNA의 자기 조립(Self-Assembly) 능력과 자기 복제 능력 및 다른 분자를 인식하여 결합하는 특성을 정보기술에 적용한 DNA 컴퓨터에 대해 설명하였다. 마지막으로, 나노 단위의 DNA 구조를 응용한 나노 기술 중에서 다양한 나노구조물을 만드는 기술인 DNA 오리가미 기술에 대해 설명하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.757-762
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• 1998

“하나로”를 이용하여 강내 조사용으로 사용되는 $^{192}$ Ir 선원의 제조법을 확립하였다. HTS (Hydraulic Transfer System)조사공에서 48시간 조사한 $\psi$2.5 mm x t 0.25 mm의 원판형 Ir 표적 10장을 쌓아서 방사능이 1.012 Ci인 선원을 시험제조하였다. 선원 제작에 관련된 생성방사능, 중성자 자기홉수효과 인자를 이론적으로 계산하여 시험제조에 사용하였고 ${\gamma}$선 자기흡수효과는 실험으로 측정하여 암 치료에 요구되는 10-20 Ci 선원의 상용생산에 필요한 자료를 확보하였다. 치료용 소선원 제작에 관련된 표적제작, 중성자조사, 방사능 측정, 선원조립, 밀봉용접, 품질관리 등의 제작기술을 확립하고 선원의 안전성은 밀봉시험, 표면오염검사 등을 수행하여 확인하였다. 제조된 선원은 실제 사용되는 조사장치에 장착하여 기능시험을 수행할 것이다. 이번 실험을 통하여 강내 조사용으로 사용되는 10-20 Ci 방사능의 $^{192}$ Ir 선원을 안정적으로 공급할 수 있음을 확인하였으며 하나로를 이용하여 캡슐 직경 4 mm의 치료용 소선원 제작기술을 확립하였다. 개발된 /spp 192/Ir 강내 조사용 선원은 국내 5-6개 병원에 공급할 것이며 이 기술을 바탕으로 직경 1.1-1.6 mm의 강내 조사용 선원도 개발할 예정이다.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.3
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• pp.147-158
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• 1997

This paper presents the analysis technique and procedure of main engine components-cylinder block, cylinder liners, gasket and cylinder head-using the finite element method, which aims to assess mainly the potential of lower oil consumption in a view point of engine design and to decide subsequently the accuracy of engine design which was done. The F.E. model of an engine section consisting of one whole cylinder and two adjacent half cylinders is used, whereby the crankcase is cut off at the block bottom deck. By means of a 3-dimensional F.E. model-including cylinder block, liners, gasket, cylinder head, bolts and valve seat rings as separate parts a linear analysis of deformations and stresses was performed for three different loading conditions;assembly, thermal and gas loads. For the analysis of thermal boundary conditions also the temperature field had to be evaluated in a subsequent step.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.2-3
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• 2005

Air gap control method using a conventional actuator for near field recording technology has been reported. To achieve good performance in the air gap servo and further experiments, the assembling between OL and SIL is the critical procedure. A lens set with NA 1.45 at 405 m has been assembled and tested by using a Twyman-Green interferometer. The tolerance of assembling is very tight and the designing and adjusting procedure must be carefully controlled.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1661-1667
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• 2008

Recently, a rolling stock has been requiring more efficient manufacturing method than welding for the improved quality and the enhanced fabrication of car body structure. As an alternative, modularization of car body structure is being studied. Accordingly, rolling stock manufacturers need to make it possible to develop a variety of rolling stock vehicles made from modularized sub-blocks in order to meet various customer's demands. The bolt-assembled car body structure for modularization is known to have many advantages over the existing weld-assembled method and is free from the possible welding defects, such as welds between dissimilar metals, crack, deformation and loss of strength. Consequently, we can have the improved overall quality, the reduced man powers for assembly and the satisfied strength of car body structure. The review is about the bolt-assembled car body structure for modularization to assure global competitiveness and an enhanced technique in terms of assembly methodology of car body structure.