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Interaction Scheme (interaction + scheme)
Selected AbstractsInstationary aeroelastic computation of yacht sailsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2001Heinrich Schoop Abstract Effective schemes exist to calculate aerodynamic forces for thin bodies and structural dynamics of flexible membranes. The fluid dynamic of thin wings in a irrotational flow leads to the lifting surface theory. Neglecting the inertia of the membrane the structural dynamics are solved by the non-linear (FEM). But the interaction of flexible membranes and an irrotational flow causes problems due to the different nature of the mathematical equations. On the one hand, there is a partial differential equation for the structural dynamics and on the other hand, there is a singular integral equation for the aerodynamics. The numerical discretization scheme has to fit these different types of equation. Our work introduces a new interaction scheme to couple the singular integral equation of the lifting surface theory with the non-linear FEM of the membrane static. The fundamental examinations, showed by Schoop et al. (International Journal for Numerical Methods in Engineering 1998; 41: 217,219), are applied to realistic sail geometries and the aerodynamics is extended to instationary flow conditions. Copyright © 2001 John Wiley & Sons, Ltd. [source] Two isomorphous crotonatolanthanide complexes: tetra-,-but-2-enoato-bis[diaqua(but-2-enoato)Ln],2,6-diaminopurine (1/2) (Ln = Dy and Ho)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009Ana Marķa Atria The title isomorphous compounds, tetra-,-but-2-enoato-bis[diaqua(but-2-enoato)dysprosium(III)],2,6-diaminopurine (1/2), [Dy2(C4H5O2)6(H2O)4]·2C5H6N6, and tetra-,-but-2-enoato-bis[diaqua(but-2-enoato)holmium(III)],2,6-diaminopurine (1/2), [Ho2(C4H5O2)6(H2O)4]·2C5H6N6, consist of [Ln(crot)3(H2O)2]2 dimers (crot is crotonate or but-2-enoate; Ln is the lanthanide cation), built up around inversion centres and completed by 2,6-diaminopurine molecules. The lanthanide cation is coordinated by three chelating crotonate units and two water molecules. One of the chelating carboxylate groups acts also in a bridging mode sharing one O atom with both cations and the final result is a pair of DyO9 tricapped prismatic polyhedra linked to each other through a central (Dy,O)2 loop. A feature of the structures is the existence of a complex intermolecular interaction scheme involving two sets of tightly interlinked non-intersecting one-dimensional structures, one of them formed by the [Dy(crot)3(H2O)2]2 dimers (running along [100] and linked by O,H...O hydrogen bonds) and the second formed by 2,6-diaminopurine molecules (evolving along [010] linked by N,H...N hydrogen bonds). [source] Diaqua(oxydiacetato-,3O,O,,O,,)(pyridine-3-carboxamide-,N1)copper(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Mireille Perec In the mononuclear title compound, [Cu(C4H4O5)(C6H6N2O)(H2O)2], the CuII centre is bound to a chelating oxydiacetate ligand, a monodentate pyridine-3-carboxamide unit and two water molecules, defining an octahedral coordination where the first two ligands form the equatorial plane and the last two occupy the apical sites. The planar oxydiacetate ligand is slightly disordered at its central ether O atom. The availability of efficient donors and acceptors for hydrogen bonding results in a complex interaction scheme where each monomer links to six similar units to define a well connected three-dimensional structure. A comparison is made with related structures in the literature, and the reasons for their differences are discussed. [source] Theory of chemical bonds in metalloenzymes XIII: Singlet and triplet diradical mechanisms of hydroxylations with iron-oxo species and P450 are revisitedINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2009Kizashi Yamaguchi Abstract Electronic structures of the Compound I (CpdI) in P450 are investigated on the basis of spin coupling forms of iron-oxo (Fe(IV)O) cores and radical ligand (,L) groups to generalize previous singlet and triplet diradical (TD) mechanisms for oxygenations of alkanes with Fe( IV)O. Orbital interaction schemes for four lower-lying spin configurations of CpdI with HC bond of substrate are examined to elucidate how magnetic coupling modes correlate with radical reaction pathways for hydroxylation reactions on the basis of the broken symmetry (BS) molecular orbital (MO) model. The configuration correlation diagrams for the four configurations model are depicted on the basis of the isoelectronic analogy among O, O2, and Fe( IV)O, in addition to Coulomb exchange energy on the iron site, which determines its local spin configuration. Important role of ligand spin (,L) of CpdI for regulation of hydroxylation mechanisms is clarified with the aid of the spin coupling forms. Transition states for one quartet and three doublet configurations under the BS MO approximation are examined on the basis of potential curve crossings along reaction pathways. The four transition structures and corresponding radical intermediates for methane and trimethyl methane with CpI are located by the BS hybrid Kohn,Sham density functional theory (DFT) (B3LYP) method to confirm the orbital interaction schemes. Spin density populations obtained by the BS B3LYP calculations are found to be consistent with the theoretical predictions based on the four configurations model. The configuration and state correlation diagrams by BS B3LYP before and after spin projection are also consistent with the BS MO interaction schemes, which provide local SD and TD mechanisms of hydroxylation with CpdI. The present BS MO-theoretical framework is useful for systematic understanding of a lot of recent BS hybrid DFT computational results for hydroxylation reactions with CpdI and configuration correlation diagrams reported by several groups. Implications of the present theoretical and computational results are discussed in relation to several experimental characteristics of hydroxylation reactions with iron-oxo species and P450. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source] | ||||||||||