• 제목/요약/키워드: residual thickness

검색결과 534건 처리시간 0.027초

열-나노임프린트 리소그래피 공정에서의 폴리머 유동에 대한 해석적 접근 (Analytical Approach of Polymer Flow in Thermal Nanoimprint Lithography)

  • 김국원;김남웅
    • 한국공작기계학회논문집
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    • 제17권3호
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    • pp.20-26
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    • 2008
  • Nanoimprint lithography(NIL) is becoming next generation lithography of significant interest due to its low cost and a potential patterning resolution of 10nm or less. Success of the NIL relies on the adequate conditions of pressure, temperature and time. To have the adequate conditions for NIL, one has to understand the polymer flowing behavior during the imprinting process. In this paper, an analytical approach of polymer flow in thermal NIL was performed based on the squeeze flow with partial slip boundary conditions. Velocity profiles and pressure distributions of the polymer flow were obtained and imprinting forces and residual thickness were predicted with the consideration of the slip velocity between the polymer and the mold/substrate. The results show that the consideration of the slip is very important for investigating the polymer flow in Thermal NIL.

Elememtwise Patterned stamp와 부가압력을 이용한 UV 나노임프린트 리소그래피 공정

  • 손현기;정준호;심영석;이응숙
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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    • pp.126-126
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    • 2004
  • 1996년 Chou 등이 개발한 가열방식의 나노임프린트 리소그래피(nanoimprint lithography, NIL)은 선폭 100nm 이하의 나노구조물을 경제적으로 제작할 수 있는 대표적인 나노패턴닝(nano-patterning) 공정으로 많은 기대가 모아지고 있으나, 열변형에 의해 다층정렬이 어렵다는 점과, 점도가 큰 레지스트(resist)를 임프린트하기 위해서는 고압(∼30 bar)이 필요하다 점 등의 문제점이 있다. 이를 해결할 수 있는 방법으로 UV 나노임프린트 리소그래피(ultraviolet nanoimprint lithography, UV-NIL)를 들 수 있다.(중략)

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잔여 지열류량과 대륙지각의 특성 (Residual Heat Flow and Crustal Properties)

  • 한욱
    • 자원환경지질
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    • 제27권4호
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    • pp.397-409
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    • 1994
  • 지각의 두께에 따른 지열류량을 표시한 그림에서 나타나는 산만성은 다른 두개의 구조구를 전제하고 지구 동력학적 과정과 열적 감쇠현상을 적용하면 설명이 분명하게 된다. 높은 지열류량은 지각이 가늘게 확장되어 얇아진 열곡지역뿐만 아니라 트러스트 구조작용으로 지각이 두껍게 되고 지각의 열생산이 많은 조산대 지역의 특징이다. 지질학적 시간이 경과함에 따라서 지각평형작용에 의해 두꺼운 지각은 융기와 침식작용으로 얇게 되며 얇은 지각은 침강과 퇴적작용으로 두껍게 된다. 지열류량은 배경의 맨틀 지열류량과 평형을 이루는 값까지 감소하게 된다.

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Hertzian Crack Suppression and Damage Tolerance of Silicon Nitride Bilayer

  • Lee, Kee-Sung;Kim, Do-Kyung;Lee, Seung-Kun;Lawn, Brian R.
    • The Korean Journal of Ceramics
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    • 제4권4호
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    • pp.356-362
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    • 1998
  • Hertzian crack suppression phenomena and relatively high damage tolerance were investigated in hard/soft silicon nitride ($Si_3N_4$) bilayers. Coarse $\alpha}-Si_3N_4$ powder was wsed for the hard coating layer and fine $\alpha}-Si_3N_4$ powder was used for the soft substrate layer. The two layers were designed with a strong interface. Hertzian indentation was used to investigate contact fracture and damage tolerance property. Hertzian crack suppression has occurred with increasing applied load and decreasing coating thickness. The crack suppression contributed strength improvement, especially in the bilayers with thinner coatings. Ultimately, the combination of hard coating with soft but tough underlayer improved the damage tolerance of brittle $Si_3N_4$ ceramics.

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장력법을 이용한 필릿용접변형의 감소에 관한 연구 (A Study on the Reduction of Fillet Welding Deformation by Applying the Tensioning Method)

  • 이주성;박재우
    • 대한조선학회논문집
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    • 제44권6호
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    • pp.590-597
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    • 2007
  • The portion of thin plate is expected to increases as to the development of design and fabrication technology. The weld-induced deformation is more serious in thin plates than in thick plates because heat affect zone of thin plates is wider than that of thick plates, and in addition internal and external constraints much more influence upon weld-induced deformation of thin plates. This paper is aimed at applying the mechanical tensioning method to fillet weld of thin plates to reduce the weld-induced deformation. For this purpose, fillet welding tests have been carried out for several thin plate specimens with varying plate thickness and magnitude of tensile load. From the present study, it has been found that the tensioning method is effective on reduction of weld-induced deformation.

국부좌굴을 고려하는 개선소성힌지해석을 이용한 3차원 강뼈대 구조물 해석 (3-D Frame Analysis Using Refined Plastic-Hinge Analysis Accounting for Local Buckling)

  • 김승억;박주수
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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    • pp.319-326
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    • 2001
  • In this paper, 3-D frame design using refined plastic-hinge analysis accounting for local buckling is developed. This analysis accounts for material and geometric nonlinearities of the structural system and its component members. Moreover, the problem associated with conventional refined plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by local buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model consisting of the width-thickness ratio is used to account for local buckling. The proposed analysis is verified by the comparison of the LRFD results.

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강제 교각의 거동에 관한 연구 (A Study on the Structural Behavior of Welded Box Columns)

  • 김인한;손용석;엄진호;송준엽;권영봉
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1999년도 가을 학술발표회 논문집
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    • pp.87-94
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    • 1999
  • The structural behavior of welded steel box columns subjected to axial compression and combined load of axial and horizontal load is described. The nonlinear stress-strain relation of the material and residual stress resulted from welds were included in the analysis. Inelastic buckling analysis of hollow rectangular sections of various width-thickness and slenderness ratios was carried out using the semi-analytical and spline finite strip method to investigate the local and global bucking stress and mode interaction. The buckling stress was compared with test results and design curves. Post-buckling behavior was traced by the finite element program(ADINA) and compared with experimental results. The comparison showed that the ultimate stress can be used for the design purpose.

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경사기능성 지르코니아 용사피복층의 열 및 기계적특성 (Thermal and Mechanical Characteristics of Functionally Graded ZrO$_2$ Thermal Spray Coating)

  • 오동현
    • 한국표면공학회지
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    • 제31권2호
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    • pp.91-100
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    • 1998
  • NiCrAlY/YSZ(8wt%$Y_2O_3-ZrO_2$) functionally graded thermal barrier coating (FGC) layers on a Co-base superalloy (HAYNESS 188) substrate were fabstrate were fabicated using Ar shielded single torch air plasma spraying method. Functional grading with the stepwise compositional change throughout layer thickness. Microstructural observation trvealed a successful fabrication of NiCrAlY/YSZ FGC. From the results of the curvature measurement, adhesive strength measurement and thermal shock test for the FGC, it was concluded that the optimum conditions of functionally graded coating layer thinkness and compositional pattern exit to enhance the properties of FGC, which is closely related to the internal residual stess distribution witin it.

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Bolted joints for single-layer structures: numerical analysis of the bending behaviour

  • Lopez-Arancibia, A.;Altuna-Zugasti, A.M.;Aldasoro, H. Aizpurua;Pradera-Mallabiabarrena, A.
    • Structural Engineering and Mechanics
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    • 제56권3호
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    • pp.355-367
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    • 2015
  • This paper deals with a new designed joint system for single-layer spatial structures. As the stability of these structures is greatly influenced by the joint behaviour, the aim of this paper is the characterization of the joint response in bending through Finite Element Method (FEM) analysis using ABAQUS. The behaviour of the joints studied here was influenced by many geometrical factors, such as bolts and plate sizes, distance between bolts and end-plate thickness. The study comprised five models of joints with different values of those parameters. The numerical results were compared to the results of previous experimental tests and the agreement was good enough. The differences between the numerical and experimental initial stiffness are attributed to the simplifications introduced when modelling the bolt threads as well as the presence of residual stresses in the test specimens.

투과증발을 이용한 부탄올 추출발효 시스템의 모델링과 분석 (Modeling and Analysis of Extractive Butanol Fermentation with Pervaporation)

  • 김성훈;박창호
    • KSBB Journal
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    • 제15권5호
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    • pp.529-536
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    • 2000
  • Results from experiments and mathematical modeling were compared for pervaporative butanol fermentation. The developed model includes expressions to predict characteristics of butanol fermentation, such as, microbial growth, solvent (butanol, acetone, and ethanol) formation and organic acid (acetate and butyrate) production. Butanol diffusivity was 1.15${\times}$10(sup)-7 ㎡/hr at 1.5 L/min-tubing of air flow rate using a pervaporative module. The model correlated well with experimental results (cell growth, glucose consumption and concentrations of solvents and organic acids) for batch fermentation with and without pervaporation. Larger surface area and thinner module tubing resulted in an increased glucose consumption and a decreased residual butanol concentration. Optimum membrane area and thickness were 0.34 ㎡ and 120 $\mu\textrm{m}$, respectively.

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