• 제목/요약/키워드: multiple materials

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도시철도 차량 유지보수를 위한 자재시스템 정보화에 대한 연구 (Material Maintenance Information System for Electric Multiple Unit)

  • 안태기
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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    • pp.241-243
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    • 2006
  • To supply the materials the right time, and the right place, it is required some information maintenance system to manage this procedure effectively. In this paper, we represent the standard products classification for EMU and the materials maintenance information system to manage the parts used EMU maintenance efficiently. The standard material classification is matched to G2B code made by the Supply Administration. The implemented material information system can perform various functions such as the inquiry of the number of stocks, the demand of the materials, and etc.

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보온력에 미치는 피복재료와 겹침의 영향 (The effects of Clothing Materials and Multi-layered Textiles on Thermal Resistance Value)

  • 손원교;차옥선
    • 대한가정학회지
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    • 제37권11호
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    • pp.157-165
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    • 1999
  • This study was carried out to examine the effect of clothing materials and multi-layered textiles on thermal resistance value. Cotton, polyester, wool, silk, rayon and acetate were selected for the specimens. Thermal resistance value was tested with 2 kinds of methods(thermo labo II and BK type tester). The results were as follows; 1. The effects of clothing materials for thermal resistance value were decreased by adding layers. 2. When the fabrics are measured with multiple layers, the fabric of the lowest thermal resistance value at single layer was showed the highest increasing tendency for all test methods.

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Interfacial modulus mapping of layered dental ceramics using nanoindentation

  • Theocharopoulos, Antonios L;Bushby, Andrew J;P'ng, Ken MY;Wilson, Rory M;Tanner, K Elizabeth;Cattel, Michael J
    • The Journal of Advanced Prosthodontics
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    • 제8권6호
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    • pp.479-488
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    • 2016
  • PURPOSE. The aim of this study was to test the modulus of elasticity (E) across the interfaces of yttria stabilized zirconia (YTZP) / veneer multilayers using nanoindentation. MATERIALS AND METHODS. YTZP core material (KaVo-Everest, Germany) specimens were either coated with a liner (IPS e.max ZirLiner, Ivoclar-Vivadent) (Type-1) or left as-sintered (Type-2) and subsequently veneered with a pressable glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). A $5{\mu}m$ (nominal tip diameter) spherical indenter was used with a UMIS CSIRO 2000 (ASI, Canberra, Australia) nanoindenter system to test E across the exposed and polished interfaces of both specimen types. The multiple point load - partial unload method was used for E determination. All materials used were characterized using Scanning Electron Microscopy (SEM) and X - ray powder diffraction (XRD). E mappings of the areas tested were produced from the nanoindentation data. RESULTS. A significantly (P<.05) lower E value between Type-1 and Type-2 specimens at a distance of $40{\mu}m$ in the veneer material was associated with the liner. XRD and SEM characterization of the zirconia sample showed a fine grained bulk tetragonal phase. IPS e-max ZirPress and IPS e-max ZirLiner materials were characterized as amorphous. CONCLUSION. The liner between the YTZP core and the heat pressed veneer may act as a weak link in this dental multilayer due to its significantly (P<.05) lower E. The present study has shown nanoindentation using spherical indentation and the multiple point load - partial unload method to be reliable predictors of E and useful evaluation tools for layered dental ceramic interfaces.

A multiple level set method for modeling grain boundary evolution of polycrystalline materials

  • Zhang, Xinwei;Chen, Jiun-Shyan;Osher, Stanley
    • Interaction and multiscale mechanics
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    • 제1권2호
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    • pp.191-209
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    • 2008
  • In this paper, we model grain boundary evolution based on a multiple level set method. Grain boundary migration under a curvature-induced driving force is considered and the level set method is employed to deal with the resulting topological changes of grain structures. The complexity of using a level set method for modeling grain structure evolution is due to its N-phase nature and the associated geometry compatibility constraint. We employ a multiple level set method with a predictor-multicorrectors approach to reduce the gaps in the triple junctions down to the grid resolution level. A ghost cell approach for imposing periodic boundary conditions is introduced without solving a constrained problem with a Lagrange multiplier method or a penalty method. Numerical results for both uniform and random grain structures evolution are presented and the results are compared with the solutions based on a front tracking approach (Chen and Kotta et al. 2004b).

시츄견에서 다발성 피지선종과 항문주위선종의 혼합 발생 (Multiple Sebaceous Gland Adenoma and Perianal Gland Adenoma in a Shih Tzu Dog)

  • 강상철;양형석;정종태;한동균;배종희;김재훈
    • 한국임상수의학회지
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    • 제21권2호
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    • pp.187-190
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    • 2004
  • A mixed case of multiple sebaceous gland adenoma and perianal gland adenoma was found in a 11-year-old male Shih Tzu dog. Grossly, many masses less than 1 cm in diameter of back skin and single red-brown mass about 0.5 cm in diameter of inner ear were noted. In addition one of light-pink mass 5 cm in diameter was presented in the anus. All of the masses were well demarcated and dome-shaped or papillated nodules. Histologically, the mass from back and ear were composed with multiple irregular shaped or sized lobules of sebaceous glands. Masses were containing mostly mature sebaceous cells and multifocal cystic degeneration with acellular and bright eosinophilic materials. And the mass from peri-anal area was well-circumscribed and composed of broad, anastomosing trabeculae of well-differentiated hepatoid cells. There were very low mitotic figures in all masses. Based on these results, this case was diagnosed as the multiple sebaceous gland adenoma and perianal gland adenoma.

Optimal design of a piezoelectric passive damper for vibrating plates

  • Yun, Chul-Yong;Kim, Seung-Jo
    • International Journal of Aeronautical and Space Sciences
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    • 제7권2호
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    • pp.42-49
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    • 2006
  • In this paper, an efficient piezoelectric passive damper is newly devised to suppress the multi-mode vibration of plates. To construct the passive damper, the piezoelectric materials are utilized as energy transformer, which can transform the mechanical energy to electrical energy. To dissipate the electrical energy transformed from mechanical energy, multiple resonant shunted piezoelectric circuits are applied. The dynamic governing equations of a coupled electro-mechanical piezoelectric with multiple piezoelectric patches and multiple resonant shunted circuits is derived and solved for the one edge clamped plate. The equations of motion of the piezoelectrics and shunted circuits as well as the plate are discretized by finite element method to estimate more exactly the effectiveness of the piezoelectric passive damper. The method to find the optimal location of a piezoelectric is presented to maximize effectiveness for desired modes. The electro-mechanical coupling term becomes important parameter to select the optimal location.

Development of Multiple CMP Monitoring System for Consumable Designs

  • Park, Sun-Joon;Park, Boum-Young;Kim, Sung-Ryul;Jeong, Hae-Do;Kim, Hyoung-Jae
    • Transactions on Electrical and Electronic Materials
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    • 제8권1호
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    • pp.11-14
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    • 2007
  • Consumables used in Chemical Mechanical Polishing (CMP) have been played important role to improve quality and productivity. Since the properties of consumables constantly change with various reasons, such as shelf time, manufactured time, lot to lot variation from supplier and so on, CMP results are not constant during the process. Also, CMP process results are affected by multiple sources from wafer, conditioner, pad and slurry. Therefore, multiple sensing systems are required to monitor CMP process variation. In this paper, the authors focus on development of monitoring system for CMP process which consist of force, temperature and displacement sensor to measure the signal from CMP process. With monitoring systems mentioned above, complex CMP phenomena can be investigated more clearly.

자유단조 공정 시 내부 기공 거동 예측을 위한 멀티스케일 유한요소해석 연구 (A Study of Multiple Scale FEM Modeling for Prediction of Inner Void Closing Behavior in Open Die Forging Process)

  • 곽은정;강경필;이경훈
    • 소성∙가공
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    • 제21권5호
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    • pp.319-323
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    • 2012
  • In order to predict the internal void closing behavior in open die forging process, multiple scale modeling has been developed and applied. The huge size difference between ingot and inner void makes it almost impossible to simultaneously model the actual loading conditions and the void shape. Multiple scale modeling is designed to integrate macro- and micro- models effectively and efficiently. The void closing behavior was simulated at 39 different locations in a large ingot during upsetting and cogging. The correlation between the closing behavior and variables such as effective plastic strain and maximum compressive strain was studied in order to find an efficient measure for predicting the soundness of the forging.

High performance ultrafine-grained Ti-Fe-based alloys with multiple length-scale phases

  • Zhang, Lai-Chang
    • Advances in materials Research
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    • 제1권1호
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    • pp.13-29
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    • 2012
  • In order to simultaneously enhance the strength and plasticity in nanostructured / ultrafine-grained alloys, a strategy of introducing multiple length scales into microstructure (or called bimodal composite microstructure) has been developed recently. This paper presents a brief overview of the alloy developement and the mechanical behavior of ultrafine-grained Ti-Fe-based alloys with different length-scale phases, i.e., micrometer-sized primary phases (dendrites or eutectic) embedded in an ultrafine-grained eutectic matrix. These ultrafine-grained titanium bimodal composites could be directly obtained through a simple single-step solidification process. The as-prepared composites exhibit superior mechanical properties, including high strength of 2000-2700 MPa, large plasticity up to 15-20% and high specific strength. Plastic deformation of the ultrafine-grained titanium bimodal composites occurs through a combination of dislocation-based slip in the nano-/ultrafine scale matrix and constraint multiple shear banding around the micrometer-sized primary phase. The microstructural charactersitcs associated to the mechanical behaivor have been detailed discussed.

SNR Enhancement Algorithm Using Multiple Chirp Symbols with Clock Drift for Accurate Ranging

  • Jang, Seong-Hyun;Kim, Yeong-Sam;Yoon, Sang-Hun;Chong, Jong-Wha
    • ETRI Journal
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    • 제33권6호
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    • pp.841-848
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    • 2011
  • A signal-to-noise ratio (SNR) enhancement algorithm using multiple chirp symbols with clock drift is proposed for accurate ranging. Improvement of the ranging performance can be achieved by using the multiple chirp symbols according to Cramer-Rao lower bound; however, distortion caused by clock drift is inevitable practically. The distortion induced by the clock drift is approximated as a linear phase term, caused by carrier frequency offset, sampling time offset, and symbol time offset. SNR of the averaged chirp symbol obtained from the proposed algorithm based on the phase derotation and the symbol averaging is enhanced. Hence, the ranging performance is improved. The mathematical analysis of the SNR enhancement agrees with the simulations.