排序方式: 共有8条查询结果,搜索用时 15 毫秒
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Optimal operation policies were investigated for a batch reactor system with two different operation stages. At the end of
the first nonisothermal stage one of the reactants was added. Since that moment the reactor was operated isothermally. In
each stage behavior of the reactor was described by a set of differential equations. The maximum conversion problem was investigated
subject to various operating constraints. Dynamic optimization based on the control vector parametrization was used to find
the optimal control profile. Gradients of the resulting nonlinear programming problem were obtained by adjoint method based
on the optimal control theory. 相似文献
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Fikar Christian Hirsch Patrick Nolz Pamela C. 《Central European Journal of Operations Research》2018,26(2):423-442
Central European Journal of Operations Research - This work presents an agent-based simulation optimization framework to model the impact of transport disruptions and word of mouth on disaster... 相似文献
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Stibrany RT Fikar R Brader M Potenza MN Potenza JA Schugar HJ 《Inorganic chemistry》2002,41(20):5203-5215
A series of Cu(II) and Cu(I)/Cu(II) complexes containing the cis-N(amine)(2)S(thiolate)(2) copper complex rac-2 has been synthesized to provide a basis for understanding the charge-transfer spectra of mixed-valence thiolate-bridged Cu(I)/Cu(II) complexes. In combination with Cu(Me(2)-13-N(4)ane), rac-2 yields a monobridged dinuclear homovalent adduct, rac-5, while reaction with CuCl yields the mixed-valance pentanuclear complex rac-6. In the presence of Cu(II)(acac)(2), chiral R,R-1 reacts to form a mixed-valence pentanuclear cation R,R-7. rac-6 exhibits a relatively short Cu(I). Cu(II) contact [2.8231(9) A] and associated structural features that suggest the presence of a weak Cu(I).Cu(II) interaction in a valence-trapped system. Additional structural features in rac-6 and R,R-7 include singly and doubly bridging thiolates, three- and four-coordinated Cu(I) ions, and varying Cu(I) ligand sets. These features extend the types and complexities of electronic absorptions significantly. Spectra of rac-6 and R,R-7 exhibit multiple overlapping absorptions over the entire visible and ultraviolet spectral regions studied, consonant with these observations. Trends resulting from variations in structure type and oxidation state permit a first approach toward developing a detailed assignment of the individual ligand Rydberg, LF, LMCT, MLCT, and possible MMCT absorptions in these complexes. 相似文献
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Annals of Operations Research - Demand for and production of organic fresh food play an increasing role worldwide. As a result, a growing amount of fresh fruits and vegetables has to be transported... 相似文献
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Mechanical spectroscopy measurements were performed on decagonal quasicrystalline Al–Cu–Fe–Cr coatings of three different thicknesses deposited on a mild steel substrate. The mechanical loss spectra indicate that the internal friction is mostly caused by the quasicrystalline coating and that the contributions of both the steel substrate and the interface are small. The shear modulus measured in torsion increases with temperature, while the Young’s modulus measured in flexion behaves normally. This shear modulus anomaly is interpreted as being due to solid friction between cracked segments of the quasicrystalline coating. This phenomenon also explains the broad athermal maximum found to occur in isochronal internal friction measurements. A quantitative model successfully reproducing the observed behaviour has been developed. Finally, the reversible high-temperature exponential background was interpreted as being due to the onset of the brittle-to-ductile transition in the quasicrystalline coating. The measured activation enthalpy is similar to the value that was deduced from compression tests performed at high temperatures on icosahedral Al–Cu–Fe bulk material. 相似文献
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Michal Čižniar Marián Podmajerský Tomáš Hirmajer Miroslav Fikar Abderrazak M. Latifi 《Chemical Papers》2009,63(3):274-283
The estimation of parameters in semi-empirical models is essential in numerous areas of engineering and applied science. In
many cases, these models are described by a set of ordinary-differential equations or by a set of differential-algebraic equations.
Due to the presence of non-convexities of functions participating in these equations, current gradient-based optimization
methods can guarantee only locally optimal solutions. This deficiency can have a marked impact on the operation of chemical
processes from the economical, environmental and safety points of view and it thus motivates the development of global optimization
algorithms. This paper presents a global optimization method which guarantees ɛ-convergence to the global solution. The approach consists in the transformation of the dynamic optimization problem into
a nonlinear programming problem (NLP) using the method of orthogonal collocation on finite elements. Rigorous convex underestimators
of the nonconvex NLP problem are employed within the spatial branch-and-bound method and solved to global optimality. The
proposed method was applied to two example problems dealing with parameter estimation from time series data. 相似文献
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For the plane symmetry we have found the electro-vacuum exact solutions of the Einstein-Maxwell equations and we have shown that one of them is equivalent to the McVittie solution of a charged infinite thin plane. The analytical extension has been accomplished and the Penrose conformal diagram has been obtained as well. 相似文献
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