• 제목/요약/키워드: rheometry

검색결과 40건 처리시간 0.024초

개선된 회전형 레올로지 측정법을 이용한 박형 반도체 패키지 내에서의 3차원 몰드 유동현상 연구 (Full Three Dimensional Rheokinetic Modeling of Mold Flow in Thin Package using Modified Parallel Plate Rheometry)

  • 이민우;유민;유희열
    • 한국마이크로전자및패키징학회:학술대회논문집
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    • 한국마이크로전자및패키징학회 2003년도 기술심포지움 논문집
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    • pp.17-20
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    • 2003
  • The EMC's rheological effects on molding process are evaluated in this study. When considering mold processing for IC packages, the major concerning items in current studies are incomplete fill, severe wire sweeping and paddle shifts etc. To simulate EMC's fast curing rheokinetics with 3D mold flow behavior, one should select appropriate rheometry which characterize each EMC's rheological motion and finding empirical parameters for numerical analysis current studies present the new rheometry with parallel plate rheometry for reactive rheokinetic experiments, the experiment and numerical analysis is done with the commercial higher filler loaded EMC for the case of Thin Quad Plant Packages (TQFP) with package thickness below 1.0 mm. The experimental results and simulation results based on new rheometry matches well in point of the prediction of wire sweep, filling behavior of melt front advancement and void trapping position.

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Controlled-stress rotational rheometry : An historical review

  • Barnes, Howard A.;Bell, Derek
    • Korea-Australia Rheology Journal
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    • 제15권4호
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    • pp.187-196
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    • 2003
  • The recent renaissance in controlled-stress rheometry has meant that more and more commercial models of this type of instrument have appeared in the (rheological) marketplace and many papers now deal with the results obtained by their use. It is therefore both timely and appropriate that this mode of rheometry should be reviewed for the sake of new and old users who are probably not be aware of its development. The history of controlled-stress measurements is therefore given, and the particular efforts of the late Jack Deer in the 1970s are chronicled, and then the later developments that have made it possible that such low torques can now be applied and such low rotational speeds measured. These have been mostly in the areas of air bearing and optical disc technologies. The typical results now obtained are illustrated.

Measurement of cell aggregation characteristics by analysis of laser-backscattering in a microfluidic rheometry

  • Shin, Se-Hyun;Hou, J.X.;Suh, Jang-Soo
    • Korea-Australia Rheology Journal
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    • 제19권2호
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    • pp.61-66
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    • 2007
  • The aggregation characteristics of red blood cells (RBCs) are known as important factors in the microvascular flow system, and increased RBC aggregation has been observed in various pathological diseases, such as thrombosis and myocardial infarction. This paper describes a simple microfluidic device for measuring the RBC aggregation by integrating a microfluidic slit rheometry and laser-backscattering technique. While a decreasing-pressure mechanism was applied to the microfluidic rheometry, a syllectogram (the light intensity versus time) showed an initial increase and a peak caused by the high shear stress-induced disaggregation, immediately followed by a decrease in the light intensity due to RBC aggregation. The critical shear stress (CST) corresponding to the peak intensity was examined as a new index of the RBC aggregation characteristics. The CST of RBCs increased with increasing aggregation-dominating protein (fibrinogen) in the blood plasma. The essential feature of this design was the combination of the rheometric-optic characterization of RBC aggregation with a microfluidic chip, which may potentially allow cell aggregation measurements to be easily carried out in a clinical setting.

Rheometry of complex fluids

  • Mewis, Jan;Moldenaers, Paula
    • Korea-Australia Rheology Journal
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    • 제11권4호
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    • pp.313-320
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    • 1999
  • The difficulties involved in measuring rheological characteristics of complex fluids are discussed. Possible measurement errors, related to the complex nature of the sample, are reviewed. They are explained in terms of the various physical and chemical mechanisms that can cause them. This leads to possible strategies and techniques for avoiding measurement errors and for obtaining useful structural information from rheological experiments on complex materials. Finally, future evolutions in rheometry are discussed.

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Calculation of EHL Traction for a Model Hydrocarbon Using Molecular Simulation and Rheometry

  • Bair, Scott;McCabe, Clare;Cummings, Peter T.;Winer, Ward O.
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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    • pp.73-75
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    • 2002
  • Recently, remarkable agreement has been reported between nonequilibrium molecular dynamics simulation and high-pressure Couette rheometry on squalane. We utilized the parameters obtained from this unique collaboration along with high-pressure viscometer measurements to calculate the elastohydrodynamic traction curve. A comparison with measured traction at 1.29 GPa shows excellent agreement, confirming the validity of the measurements and simulations. It should no longer be necessary to invoke a different rheological response to explain film thickness and traction.

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Advances in measuring linear viscoelastic properties using novel deformation geometries and Fourier transform techniques

  • See, Howard
    • Korea-Australia Rheology Journal
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    • 제13권2호
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    • pp.67-81
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    • 2001
  • The development of new techniques for the dynamic measurement of linear viscoelastic properties is an active area of rheometry, and this paper surveys some novel deformation geometries which have been recently reported e.g. oscillating probe-type devices which are imbedded in or placed on the surface of the sample. Small amplitude band-limited pseudorandom noise is used for the displacement signal, with Fourier analysis of the complex waveform of the resistance force yielding the frequency dependent viscoelastic material functions (e.g. storage and loss moduli G", G"). Theoretical calculations of the fundamental equations relating force to displacement and instrument geometry, were carried out with the aid of the correspondence principle of linear viscoelasticity. The rapidity of the tests and flexibility in terms of sample preparation and stiffness mean that this basic technique should find many applications in rheometry. Three examples of oscillatory tests are presented in detail squeeze flow, imbedded needle and concentric sliding cylinder geometries.eometries.

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