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  • 1
    ISSN: 1520-6882
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 121-123 (Mar. 2007), p. 1133-1138 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Chemical mechanical polishing (CMP) is a widely used technique to achieve high level ofglobal and local planarity required in integrate circuit (IC) areas, which pleas for concentrateresearches. A preliminary wafer-scale flow model for CMP is presented considering the roughnessas well as the porosity and compressibility of the pad. Pressure distributions for three kinds of padroughness: cosine shape, two-scale cosine shape and actual roughness were given with the help ofnumerical simulation by solving the corresponding two-dimensional slurry flow model. Pressurefluctuations and peaks can be seen from the results. The model predictions will be conducive to theremoval rate and mass transport computation. The research is a qualitative one and will pave theway for further explorations of mechanisms of CMP process
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1542-6580
    Source: Berkeley Electronic Press Academic Journals
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: A numerical study has been undertaken to explore the influence of geometry and flow parameters on the entrainment of solid in an ESE nozzle system immersed in a fluidized riser. A fully three-dimensional computational model of the nozzle system has been developed and all appropriate approximations and simplifications are described. A multi-phase Eulerian-Eulerian model incorporating the kinetic theory for solid particles is used. Numerical results are obtained using the commercial Computational Fluid Dynamics software FLUENT. The results indicate that solid entrainment in the ESE system is a strong function of both geometry and flow. The optimal entrainment is seen to occur when the ratio of the draft tube diameter D to separation distance I is approximately unity. At this value, the jet of injected gas is seen to spread fully into the opening of the draft tube causing the highest transport of solid particles through the tube. The entrainment is shown to increase with increasing jet velocity across the full range of flows considered. The results are consistent with similar experimental results. The results of this study should find immediate application in the design and implementation of ESE nozzle systems.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Berkeley, Calif. : Berkeley Electronic Press (now: De Gruyter)
    ISSN: 1542-6580
    Source: Berkeley Electronic Press Academic Journals
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: This study is concerned with an industrial application involved in the manufacture of the polymer Nylon12, which is polymerised from solid monomer particles. There exists interstitial air among those particles. Oxygen in the air is a strong inhibitor of the polymerization reaction and has to be eliminated from the packed bed of monomer particles before they are introduced into the polymerization reactor. This is done by injecting nitrogen into the packed bed from the bottom of the bed. The nitrogen spreads into the packed bed displacing the air inside. This process is already being employed in the polymer processing industries. The present research focuses on how to make this oxygen elimination process more effective. The information from a parametric study can be used to improve the design and operation of the packed bed to have a more effective oxygen elimination process. Conducting the parametric study numerically saves a lot of time and cost. The numerical model used to simulate the fluid flow in packed beds was successfully validated against experimental and analytical results in previous work. This model is used to carry out a numerical parametric study. It is found that having a single jet at the centre of the packed bed is better than having 4 jets closer to the wall. Having an inclined jet instead of a jet parallel to the wall also improves the oxygen elimination process. Simulations are also done with helium as the carrier gas; though economically, it is better to use nitrogen, the purpose of using helium is to investigate the effect of the properties of the carrier gas on the oxygen elimination process.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1056-8700
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology , Physics
    Notes: Abstract Small molecules that modulate the activity of biological signaling molecules can be powerful probes of signal transduction pathways. Highly specific molecules with high affinity are difficult to identify because of the conserved nature of many protein active sites. A newly developed approach to discovery of such small molecules that relies on protein engineering and chemical synthesis has yielded powerful tools for the study of a wide variety of proteins involved in signal transduction (G-proteins, protein kinases, 7-transmembrane receptors, nuclear hormone receptors, and others). Such chemical genetic tools combine the advantages of traditional genetics and the unparalleled temporal control over protein function afforded by small molecule inhibitors/activators that act at diffusion controlled rates with targets.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 53 (1988), S. 1982-1984 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The frequency-dependent transmission coefficient of a particle tunneling through a time-dependent barrier is calculated taking into account the quantum interference effect. We consider a rectangular barrier of height V0 with a time-dependent modulation of single frequency ω. For small modulation amplitude V1, our result is exact up to order V21 for any barrier width. In the low transmission region, our result is consistent with those obtained using a semiclassical method. We find that quantum interference (two modulation quanta process) makes a significant contribution to the tunneling current. In the static approximation, ωτ(very-much-less-than)1, where τ is the barrier transit time, the contribution to the current from interference process is to cancel one-half of the tunneling current from first-order process (one modulation quantum process). To the lowest order in power series of V1/(h-dash-bar)ω, the tunneling current is reduced due to interference.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 902-907 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The Hartree–Fock treatment of cyclotron resonance (CR) [see A. H. MacDonald, J. Phys. C 18, 1003 (1985)] is generalized by including the correlation contribution to the screening by the electrons. It is found that the CR effective mass m* is an oscillatory function of the magnetic field, which is due to the filling-factor-dependent dynamic screening of the electron-impurity scattering. It is demonstrated that as the Landau levels are depleted with increasing magnetic field, m* has a maximum at half-filling. Similar behavior has also been found in CR absorption of the two-dimensional electron gas in a high-mobility heterostructure.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 14 (2002), S. 1228-1235 
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We derive a simple kinetic theory for collisional flows of identical, slightly frictional, nearly elastic spheres that is based on a physically realistic model for a frictional collision between two spheres. When the coefficient of friction is small, the equations of balance for rotational momentum and energy can be solved in approximation. This permits the rotational temperature to be related to the translation temperature and the introduction of an effective coefficient of restitution in the rate of dissipation of translation fluctuation energy. With this incorporation of the additional loss of translational energy to friction and the rotational degrees of freedom, the structure of the resulting theory is the same as for frictionless spheres. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 79 (2001), S. 3839-3841 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Temperature increase in a low density polyethylene film during the application of high dc voltage was estimated by measuring the sound velocity with a pulsed electroacoustic method. The temperature shows no change under the electric field of 50 MVm−1 at ambient temperature of 30 °C. However, the temperature increases with time, and rises to 63.7 °C in 90 min of the voltage application at ambient temperature of 60 °C. The temperature increase was caused by Joule heating and it resulted in the increase of charging current during the application of high dc voltage. The increase in charging current calculated from the temperature increase agreed well with the experimental one. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A novel chemiluminescence (CL) flow-through sensor for the determination of analgin with flow-injection analysis (FIA) based on the auto-oxidation of analgin in the presence of Tween 80 sensitized by Rhodamine 6G immobilized on a cation-exchange column is described. This sensor responds linearly to the analgin concentration in the range of 0.4 ∼ 10 mg/L, with a detection limit (3σ) of 0.15 mg/L. A complete analysis, including sampling and washing, takes 1 min with a relative standard deviation of 〈 5%. The sensor is stable for over 200 determinations and has successfully been applied to the determination of analgin in pharmaceutical preparations.
    Type of Medium: Electronic Resource
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