Sperm competition is thought to be responsible for the tremendous inter- and intraspecific variation in sperm number and size. But why several animals produce a range of sperm types,, some of which are incapable of fe...
Sperm competition is thought to be responsible for the tremendous inter- and intraspecific variation in sperm number and size. But why several animals produce a range of sperm types,, some of which are incapable of fertilizing the female's eggs, has remained unexplained for nearly 100 years. We have found that non-fertile sperm protect a male's reproductive investment by delaying female remating in the polyandrous green-veined white butterfly, Pieris napi (Pieridae).
Catalytic pyrolysis is a promising technology to produce light olefins. Gibbs free-energy minimization method was used to study the thermodynamic equilibrium distribution of olefins in catalytic pyrolysis with Aspen P...
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Catalytic pyrolysis is a promising technology to produce light olefins. Gibbs free-energy minimization method was used to study the thermodynamic equilibrium distribution of olefins in catalytic pyrolysis with Aspen Plus software. The result showed that olefin systems with different carbon numbers demonstrated a similar thermodynamic equilibrium distribution. The ethene equilibrium composition increased with increasing reaction temperature and decreased with increasing total hydrocarbon pressure. By contrast, the propene equilibrium composition reached a maximum of 40 wt% at 850-950 K under 0.1 MPa. Ethene yield and propene yield of thermodynamic equilibrium, catalytic pyrolysis and thermal pyrolysis were compared. The use of catalyst greatly increased the yields of ethene and propene, but the yields were still lower than the equilibrium data. Catalytic pyrolysis was carried out in the interaction zone where both catalytic conversion and thermal conversion were important. Propene yield was close to ethene yield at about 950 K from the thermodynamic view. Given the shape-selective effect of the catalyst on branched olefins with large carbon number, the equilibrium carbon number distribution of olefins possibly shifted from large carbon numbers to low carbon numbers, resulting in enhanced ethene and propene yields. (C) 2016 Elsevier B.V. All rights reserved.
We present a theory for the single particle dynamics of the U→∞ Anderson lattice using a projection operator which projects out of any operator its exact thermal average in the space of single particle excitations a...
We present a theory for the single particle dynamics of the U→∞ Anderson lattice using a projection operator which projects out of any operator its exact thermal average in the space of single particle excitations and is capable of handling the complex f statistics properly. It is exact in the large degeneracy limit and gives a dynamically renormalized hybridization and f level energy. In addition, we find self-energy corrections from the on-site c-f exchange and intersite RKKY exchange induced by the correlation which are absent in other truncation treatments and lead to competition between on-site screening and magnetic effects.
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