• Title/Summary/Keyword: residual structure

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Evaluation for Thin Films Characteristics of Nitride Titanium-Chromium using Arc Ion Plating (아크이온플레이팅에 의한 질화 티탄-크롬의 박막특성 평가)

  • Fujita, Kazuhisa;Yang, Young-Joon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.4
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    • pp.96-101
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    • 2011
  • The thin films of TiN have been used extensively as wear-resistant materials, for instance, such as tools of high-speed cutting, metal mold forming etc. In these days, because the thin films capable of being used more severe conditions are needed, the technologies of arc ion plating are tried to improve its characteristics. The purpose of this study is to investigate the characteristics of thin films of (Ti,Cr)N compared with those of TiN. The method of arc ion plating, which is known as showing good tight-adherence and productivity, was used. After manufacturing thin films of ($Ti_{1-x}Cr_{x}$)N (x=0~1) with change of Cr in (Ti,Cr) target, atomic concentration, structure, size of crystallite, residual stress and surface roughness of thin films on substrate were investigated. As the results, it was confirmed that Cr atomic concentrations of thin films were proportionally changed with Cr atomic concentrations of target, and thin films of ($Ti_{1-x}Cr_{x}$)N (x=0~1) showed NaCl type and CrN existed as solid solution to TiN.

Structural Control of the Compound Layers formed during Nitrocarburising in NH3-Air-C3H8 Atmospheres (NH3-Air-C3H8 분위기에서 Nitrocarburisng시 형성된 Compound Layer의 조직제어)

  • Kim, Y.H.;Choi, K.W.
    • Journal of the Korean Society for Heat Treatment
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    • v.8 no.4
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    • pp.289-301
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    • 1995
  • The effect of Air/$C_3H_8$ gas addition on the compound layer growth of steels nitrocarburised in $NH_3+Air+C_3H_8$ mixed gas atmospheres was investigated. It is considered that amount of residual $NH_3$ was varied according to alternation of Air/$C_3H_8$ mixing ratio and volume content. The compound layer formed from nitrocarburising was composed of ${\varepsilon}-Fe_{2-3}$(C, N) and ${\gamma}^{\prime}-Fe_4$(C, N). According as Air/$C_3H_8$ mixing ratio increased, the superficial content of ${\gamma}^{\prime}-Fe_4$(C, N) within the compound layer was increased, at the same time the growth rate of compound layer and porous layer was increased. In the case of alloy steel at the fixed gas composition, the growth rate of compound layer and porous layer was worse than carbon steel and compound layer phase composition structure primarily consisted of E phase. As the carbon content of materials was increasing in the given gas atmospheres, the growth rate of compound layer and porous layer was increased and the superficial content of ${\varepsilon}-Fe_{2-3}$(C, N) within the compound layer was increased.

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3-D fracture analysis of cracked aluminum plates repaired with single and double composite patches using XFEM

  • Jamal-Omidi, Majid;Falah, Mehdi;Taherifar, Davood
    • Structural Engineering and Mechanics
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    • v.50 no.4
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    • pp.525-539
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    • 2014
  • Bonded composite-patch repair has been widely used to restore or extend the service life of damaged structures due to its effectiveness as a mechanical repair technique. In this paper using extended finite element method (XFEM), three-dimensional crack models are developed to examine the fracture behavior of centrally cracked aluminum plates repaired with single and double sided composite patches. Stress intensity factor (SIF) at the crack tip is used as the fracture criterion. In this regard, the effects of the crack lengths, patch materials, orientation of plies, adhesive and patch thickness are examined to estimate the SIF of the repaired plate and the repair performance. The obtained results show that composite patches have significant effect on reduction of the SIF at the crack tip. It is also proved that using double symmetric repair, in comparison to single one, reduces considerably SIF at the crack tip. Hence, the residual strength can be improved significantly as well as fatigue life of the structure. Investigation of ply orientation effects shows SIF increase as the ply orientation is changed from $0^{\circ}$ (perpendicular to the advancing crack) to $90^{\circ}$ (parallel to the crack line). However, the effectiveness of the ply orientation depends on the loading direction and the crack direction.

Experimental and numerical prediction of the weakened zone of a ceramic bonded to a metal

  • Zaoui, Bouchra;Baghdadi, Mohammed;Mechab, Belaid;Serier, Boualem;Belhouari, Mohammed
    • Advances in materials Research
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    • v.8 no.4
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    • pp.295-311
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    • 2019
  • In this study, a three-dimensional Finite Element Model has been developed to estimate the size of the weakened zone in a bi-material a ceramic bonded to metal. The calculations results were compared to those obtained using Scanning Electron Microscope (SEM). In the case of elastic-plastic behaviour of the structure, it has been shown that the simulation results are coherent with the experimental findings. This indicates that Finite Element modeling allows an accurate prediction and estimation of the weakening effect of residual stresses on the bonding interface of Alumina. The obtained results show us that the three-dimensional numerical simulation used by the Finite Element Method, allows a good prediction of the weakened zone extent of a ceramic, which is bonded with a metal.

Distributions of Tidal Current, Salinity and Suspended Sediment in Suyoung Bay (수영만의 조류, 염분 및 부유물질의 분포)

  • KIM Cha-Kyum;LEE Jong-Sup
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.5
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    • pp.359-370
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    • 1992
  • To investigate the flow pattern and mixing process in Suyoung Bay, field observations and data analyses of tidal current, salinity and suspended sediment (SS) were carried out. Ebb flow is stronger than flood flow, and duration of ebb tide is longer than that of flood tide. Semi-diurnal component of tidal current is predominant, and current rotating clockwise occurs in the central part of the bay. The direction of the residual currents in the central part of the bay and offshore is almost N to WNW, and the speed is 4-14cm/s. Eulerian diffusion coefficients estimated from the current data have the range of $6.2\times10^4-4.2\times10^6\;cm^2/s,$ Salinity structure in Suyoung River estuary during flood tide is of partially mixed type, but is of stratified type during ebb tide. Salinity fluctuation is large at the surface, and the fluctuation decreases with depth. SS concentration in Suyoung River estuary has a higher value during ebb tide than that during flood tide. Salinity and 55 concentrations in the estuary appeared to be very sensitive to the change of river flow.

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Ultimate Strength of Dented Tubular Members(1st report) -under Axial Loads- (Dent 손상을 갖는 원통부재의 최종강도에 관한 연구(제1보) -축 하중을 받는 경우-)

  • Chun, Tae-Byung;Nho, In-Sik;Cho, Byung-Sam
    • Journal of the Society of Naval Architects of Korea
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    • v.41 no.6
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    • pp.48-55
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    • 2004
  • Loads on offshore structures are largely transferred to the bracing members in the form of axial forces. The detrimental effects of imperfections on compressive strength are well recognized. Damage in the members of offshore structures would significantly affect the compressive behavior of the members. As a result, such damages may also affect the ability of the structure to withstand the functional and environmental loads. It is important to be able to assess the residual strength of damaged members quickly and accurately. This will help operators to make the decision whether the member has to be repaired or not. In this study, a series of calculation is performed to study the effects of different parameters on the behavior of such damaged members under axial load. And the results of analysis are compared with those of experiment.

Room Temperature Preparation of Electrolytic Silicon Thin Film as an Anode in Rechargeable Lithium Battery (실리콘 상온 전해 도금 박막 제조 및 전기화학적 특성 평가)

  • Kim, Eun-Ji;Shin, Heon-Cheol
    • Korean Journal of Materials Research
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    • v.22 no.1
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    • pp.8-15
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    • 2012
  • Silicon-based thin film was prepared at room temperature by an electrochemical deposition method and a feasibility study was conducted for its use as an anode material in a rechargeable lithium battery. The growth of the electrodeposits was mainly concentrated on the surface defects of the Cu substrate while that growth was trivial on the defect-free surface region. Intentional formation of random defects on the substrate by chemical etching led to uniform formation of deposits throughout the surface. The morphology of the electrodeposits reflected first the roughened surface of the substrate, but it became flattened as the deposition time increased, due primarily to the concentration of reduction current on the convex region of the deposits. The electrodeposits proved to be amorphous and to contain chlorine and carbon, together with silicon, indicating that the electrolyte is captured in the deposits during the fabrication process. The silicon in the deposits readily reacted with lithium, but thick deposits resulted in significant reaction overvoltage. The charge efficiency of oxidation (lithiation) to reduction (delithiation) was higher in the relatively thick deposit. This abnormal behavior needs to clarified in view of the thickness dependence of the internal residual stress and the relaxation tendency of the reaction-induced stress due to the porous structure of the deposits and the deposit components other than silicon.

The effect of process variations and post thermal annealing on the properties of LPCVD polycrystalline silicon (공정변수와 후속 열처리가 저압화학증착 다결정 실리콘 박막의 특성에 미치는 영향)

  • 황완식;최승진;이인규
    • Journal of the Korean Vacuum Society
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    • v.11 no.4
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    • pp.225-229
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    • 2002
  • LPCVD silicon films were deposited at temperatures between $560^{\circ}C$ and $650^{\circ}C$ Structure, surface roughness, films thickness and residual stress were measured by using XRD, SEM, ellipsometer, $Tektak^3$, Tencor FLX-2320 and other techniques. Polysilicon films of low stress, small surface roughness were obtained when the films are deposited at $560^{\circ}C$ in the amorphous phase and subsequently annealed to make polycrystalline silicon layers at $900^{\circ}C$ -$1100^{\circ}C$. The silicon films deposited in amorphous phase and crystallized by post thermal treatment showed better mechanical properties.

The Crystal and Molecular Structures of Sulfamethoxypyridazine (Sulfamethoxypyridazine의 결정 및 분자구조)

  • Young Ja Lee;Young Ja Park
    • Journal of the Korean Chemical Society
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    • v.25 no.4
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    • pp.219-227
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    • 1981
  • The crystal structure of sulfamethoxypyridazine has been solved by the direct method and refined by least squares methods from three-dimensional data collected by the multiple-film technique to a final residual of 8.5%. Two molecules (A and B) in one asymmetric unit are different each other in the conformation about S-N(2) bond, and are linked together by N(2A)H${\ldots}$N(3B) and N(2B)H${\ldots}$O(1A)S hydrogen bonds. Benzene and pyridazine rings make the angles of $89^{\circ}$ and $77^{\circ}$ for molecules A and B respectively.

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Computer Simulation and Control performance evaluation of Ultra Precision Positioning Apparatus using Piezo Actuator (Piezo Actuator를 이용한 초정밀 위치결정기구의 Computer Simulation 및 제어 성능평가)

  • 김재열;김영석;곽이구;한재호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.118-122
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    • 2000
  • Recently, High accuracy and precision are required in various industrial field especially, semiconductor manufacturing apparatus, Ultra precision positioning apparatus, Information field and so on. Positioning technology is a very important one among them. For composition of this technology, the development of system with high speed and high resolution is needed. At start point and end position vibration must be repressed on this system for composition of position control. This vibration is arisen nose, is increased setting time, is reduced accuracy. Especially, repressed for the lead with high speed. The small actuator with high speed and high resolution is need to repression against this residual vibration. This actuator is, for example, piezo actuator, piezoelectric material that converting from electronic signal to mechanical force is adequate material, beacause of control of control to position and force. In this study, piezo electric material is used to actuator, ultra precision positioning apparatus with stage of hinge structure is designed, simulation is performed, control performance is tested by producing apparatus. For easy usage and stability in industrial field, we perform to simulation and to position control test by digital PID controller.

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