Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Simulation of reactive ion etching pattern transfer (1989)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 4664-4675 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: This paper describes a model that simulates etching profiles and process latitudes in glow-discharge bombardment-induced reactive-etching processes. Numerical results are presented for the pattern-transfer step in trilayer lithography, but this analysis is applicable to many other pattern-transfer processes. The inputs to the interface-evolution model described here are a kinetic model for the yield per incident energetic particle and a statistical mechanical model that relates the incident-yield-weighted angular distribution to the pressure, sheath thickness, and sheath voltage drop. The kinetic model is based on experimental evidence and assumes that the yield per bombarding particle is proportional to its energy. The resulting interface-evolution equation is mathematically analogous to a free-surface evolution equation in hydrodynamics. This convective partial differential equation is reduced to a coupled set of ordinary differential equations via the method of characteristics and solved numerically. More general energy-dependent yields are easily incorporated in the present formulation, but angle-dependent yields are more difficult and are not treated here. This model describes how shadowing of the surface being etched results in proximity effects in line etching and aspect-ratio-dependent etching rates in trench etching. Simulated profiles are compared to experimental trilayer etching profiles and qualitatively describe their shape and the trends that are observed as pressure or other processing parameters are varied. Simulations showing the effect of angular distributions, line proximity, and trench aspect ratio on process latitudes in trilayer lithography are presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.343823
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Viscoelastic Poiseuille flow through a curved channel: A new elastic instability (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 1691-1694 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The linear stability of the inertialess, pressure-driven Poiseuille flow of an Oldroyd-B fluid through a slightly curved channel is considered. The flow is shown to be unstable in certain flow parameter regimes. The critical conditions and the structure of the vortex flow at the onset of instability are presented. These results reveal that there is a purely elastic, instability in the flow, and the instability is a stationary mode in contrast to the elastic, oscillatory instability that occurs in Taylor-Couette flow [see Larson, Shaqfeh, and Muller, J. Fluid Mech. 218, 573 (1990)]. In addition, the mechanism of the instability is investigated through an examination of the disturbande-energy equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858223
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Observations of axisymmetric tracer particle orientation during flow through a dilute fixed bed of fibers (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2516-2528 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Direct microstructural evidence for net tracer particle orientation induced solely by hydrodynamic interactions in a dilute, disordered, fibrous media is reported. A dilute fixed bed of randomly placed fibers was constructed and glycerol/water suspensions of either synthetic akaganeite (βFeOOH, average aspect ratio 6.3) or hematite (αFe2O3, average aspect ratio 1.6) tracer particles were made to flow axially through the bed at prescribed flow rates. Conservative linear dichroism, a noninvasive light scattering technique, was employed to provide a direct measure of the orientational order parameter for the tracer particle population at the end of the bed. The effect of Brownian motion on the hydrodynamically induced order in the suspensions was studied over three orders of magnitude in scaled rotary Peclet number, 5〈P〈2000. The steady degree of particle alignment exhibited by each suspension as it exited the fiber bed was found to be in good quantitative agreement with theory [Phys. Fluids 31, 728 (1988); ibid. 31, 2769 (1988)]. Time scales characterizing the development of net order induced in the tracer populations were investigated and compared qualitatively to theoretically derived bounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858193
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The hydrodynamic stress in a suspension of rods (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 7-24 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theory is presented to describe the momentum transport properties of suspensions containing randomly placed, slender fibers. The theory is based on a diagrammatic representation of the multiple scattering expansion for the averaged Green's function as developed in the authors' previous work on the heat and mass transfer properties of fiber dispersions [Phys. Fluids A 1, 3 (1989)]. The "best one-body approximation'' is used to calculate the wavenumber-dependent, ensemble-averaged stress for both aligned and isotropically oriented fiber dispersions. Both the dilute and semidilute concentration regimes are considered. The effective viscosity is calculated as a limit unit of the previously obtained wavenumber-dependent properties. In the semidilute concentration regime the scaling form originally suggested by Batchelor [J. Fluid Mech. 46, 813 (1971)] is recovered for both orientation distributions and its relation to short range "screening'' is discussed. Corrections to this result in a "semidilute expansion'' for small volume fraction are calculated and the dependence of these corrections on orientation distribution and particle shape is demonstrated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857683
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Viscoelastic Poiseuille flow through a curved channel: A new elastic instability (1991)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 3 (1991), S. 2043-2046 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The linear stability of the inertialess, pressure-driven Poiseuille flow of an Oldroyd-B fluid through a slightly curved channel is considered. The flow is shown to be unstable in certain flow parameter regimes. The critical conditions and the structure of the vortex flow at the onset of instability are presented. These results reveal that there is a purely elastic, instability in the flow, and the instability is a stationary mode in contrast to the elastic, oscillatory instability that occurs in Taylor–Couette flow [see Larson, Shaqfeh, and Muller, J. Fluid Mech. 218, 573 (1990)]. In addition, the mechanism of the instability is investigated through an examination of the disturbance-energy equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857886
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    The average rotation rate of a fiber in the linear flow of a semidilute suspension (1990)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 2 (1990), S. 2093-2102 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Shaqfeh and Fredrickson [Phys. Fluids A 2, 7 (1990)] renormalized the multiple reflection expansion for hydrodynamic fiber interactions in a semidilute suspension, nl3(very-much-greater-than)1 and φ(very-much-less-than)1, where φ is the fiber volume fraction, n is the number of fibers per unit volume, and l is the fiber half-length. We use the results of Shaqfeh and Fredrickson to obtain the average rotation rate of a fiber in linear shear flows of a semidilute suspension. Specific results are obtained for the case where most of the fibers are oriented in a preferred direction, as occurs in simple shear and extensional flows. The correction to the O(γ(ring)) Jeffrey rotation rate [Proc. R. Soc. London Ser. A 102, 161 (1922); J. Fluid Mech. 14, 284 (1962)] due to hydrodynamic interactions is shown to be O[γ(ring)/ln(1/φ)], where γ(ring) is the shear rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857795
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    The combined effects of hydrodynamic interactions and Brownian motion on the orientation of particles flowing through fixed beds (1988)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 31 (1988), S. 2769-2780 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In a previous publication [Phys. Fluids 31, 728 (1988)], the evolution of the orientation distribution in a dilute suspension of axisymmetric "tracer'' particles flowing through a bed of fixed fibers or spheres was determined under conditions in which hydrodynamic interactions played a dominant role in determining particle orientation. In this paper, the previous results are extended to account for the effects of Brownian motion on the tracer particles and for different configuration statistics of the force in the fixed bed. In the former case, orientational evolution equations are developed and solutions obtained that are valid for large values of the rotary Peclet number (the parameter regime of greatest interest). In the latter case, it is demonstrated that, when the disturbance flow ceases to have fore–aft symmetry, a small orientational drift and dispersion are introduced into the resulting evolution equations. The latter effects are particularly important since they will occur in all fixed beds because of interactions between bed particles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.866984
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    The effect of hydrodynamic interactions on the orientation distribution in a fiber suspension subject to simple shear flow (1995)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 7 (1995), S. 487-506 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A single, non-Brownian fiber suspended in a viscous, Newtonian fluid undergoing simple shear flow rotates in one of a set of closed orbits known as Jeffery orbits. In a fiber suspension, the hydrodynamic interactions among the fibers determine the distribution of fibers among these orbits. The hydrodynamic interactions in dilute and semidilute suspensions have been studied using slender-body theory. Hydrodynamic, orientational diffusivities were obtained from an ensemble average of the fiber–fiber interactions. The steady-state fiber orientation distribution is controlled by the anisotropy and orientation dependence of the diffusivities. The steady-state and transient fiber orientation distributions are derived using a perturbation analysis for weak hydrodynamic orientational diffusion that is an extension of the work of Leal and Hinch [J. Fluid Mech. 46, 685 (1972)] for weak, isotropic, rotary Brownian motion. In the dilute regime, the steady-state experimental distributions of Anczurowski and Mason [J. Colloid Interface Science 23, 522 (1967)] do not agree with the theoretical predictions. An explanation for these discrepancies accompanied with new experimental results is presented in this work. The theoretical predictions for the steady-state orientation distribution, and the temporal orbit constant correlation function in the semidilute regime are in good agreement with the experimental results of Stover et al. [J. Fluid Mech. 238, 277 (1992)]. The correlation time for the fiber orientation is approximately inversely proportional to fiber concentration in both the dilute and semidilute regimes. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868647
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The effects of inertia on the viscoelastic Dean and Taylor–Couette flow instabilities with application to coating flows (1992)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 2415-2431 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of inertia on the elastic instabilities in Dean and Taylor–Couette flows are investigated through a linear stability analysis. The critical conditions and the structure of the vortex flow at the onset of these instabilities are presented. The results reveal that the purely elastic Dean flow is destabilized by inertial effects. It is also found that inertia destabilizes elastic Taylor–Couette flow if the rotation of the inner cylinder is the flow driving force, while it stabilizes the flow driven by rotation of the outer cylinder. The mechanism of destabilization or stabilization of these viscoelastic instabilities is investigated through an examination of the disturbance-energy equation. It is shown that Dean flow is destabilized by two separate mechanisms: a purely elastic mechanism discussed previously (i.e., energy production due to the coupling of a perturbation velocity to the polymeric stress gradient in the base state) [see Phys. Fluids A 3, 1691 (1991)] and a purely inertial mechanism discussed by Dean [Proc. R. Soc. London Ser. A 121, 402 (1928)] (i.e., energy production from Reynolds stresses). It is also shown that, when rotation of the inner cylinder drives Taylor–Couette flow, the Reynolds stresses produce energy, and thus are destablizing, while for the flow driven by the rotation of the outer cylinder alone, the Reynolds stresses dissipate energy, thus stabilizing the flow. The elastic forces remain destabilizing in both modes of operation. In a second study, a pressure-driven viscoelastic coating flow over a curved surface is examined. The results demonstrate the existence of a purely elastic stationary instability in the coating flow on a concave wall which is very similar to that which occurs in viscoelastic Dean flow. It is demonstrated that the mechanisms of instability in Dean flow and the coating flow are the same, again through an examination of the disturbance-energy equation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.858483
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Heat and mass transport in composites of aligned slender fibers (1989)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 1 (1989), S. 3-20 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A theory is presented to describe the time-dependent and steady transport properties of composite media containing randomly placed, aligned slender fibers. The formalism is based on a diagrammatic representation of the multiple scattering expansion for the configurational-averaged Green's function. Several topological reductions are performed on the series to remove long-wavelength singularities and to render the theory self-consistent. Approximations based on partial summation of the renormalized series have structures that are similar to, but distinct from, effective medium theories. The present approach is systematic and retains a unique subset of the multiple scattering series at each level of approximation. The formalism is appliedto the specific cases of steady diffusion-controlled reaction and heat conduction in composites that contain slender, aligned rods. Both the dilute and semidilute regimes are investigated. Theseresults for the diffusion-controlled reaction problem are new, and known results are recovered for heat conduction in the case of highly conductive rods. However, the method has uncovered a new semidilute expansion for the latter problem. The screening of disturbances in fibrous composites is also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.857546
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...