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51.
Madhubabu Alaparthi Dayton Jonathan Vogel Andrew G. Sykes 《Journal of chemical crystallography》2018,48(4):131-137
Molecular clips hold the potential of self-association and the ability to form host–guest complexes. Here we describe the synthesis of a 1,2-dimethoxyphenyl terminated glycoluril molecular clip (2) that binds with smaller solvent molecules by π?H–C and C=O?H–O non-covalent interactions. We obtained single crystals of 2 and 2 + CH2Cl2, CH3OH, CH3CN, and DMF solvents complexed within the clip. These solvents always form two π?H–C interactions between the aromatic rings in the clip, and CH3OH formed an additional C=O?H–O hydrogen bond with the glycoluril carbonyl group. Based on single crystal data we found that π?H–C interactions of 2 + CH2Cl2 are stronger than 2 + CH3CN and 2?+?DMF, due to the presence of stronger electron withdrawing groups in CH2Cl2, which lead to a decrease in dihedral angle of two glycoluril aromatic planes. We also investigated the non-covalent interaction energies of these solvent molecules with 2 using computational methods. 相似文献
Graphical Abstract
Several solvent adducts of a glycoluril derivative have been isolated and characterized by single crystal X-ray diffraction, revealing two common pi?H–C non-covalent bonds within the molecular clip.
52.
53.
Flat plates, both single and in tandem or side by side arrangement, are widely used in many engineering applications. Despite vast investigations of the flow structures and wakes downstream of these bluff bodies, this unsteady phenomenon yet remains a fundamental issue in many industrial applications. This paper reviews the state of the art concerning the flow over flat plates in different arrangements focusing on plates normal to the flow. Turbulent wake regions are discussed for the flat plates in side by side or tandem arrangement. Numerical studies are reviewed with emphasis on the realized turbulent models. The effect of the chosen turbulence model on the prediction of the wake region is discussed. 相似文献
54.
Among the theories of neural information coding, the neural energy coding is more accessible to global coding features than traditional neural encoding. According to the shortcomings existing in the neuronal energy model, that is, the non-smooth nature of the energy curve, we proposed an improved neuronal energy model in this paper. The modified energy model is a good choice for establishment of the global model of brain function. And it is also the basis of energy calculation for functional cognitive neural networks in the future. 相似文献
55.
56.
Urban Larsson Richard J. Nowakowski Carlos P. Santos 《International Journal of Game Theory》2018,47(2):653-671
Combinatorial scoring games, with the property ‘extra pass moves for a player will do him no harm’, are characterized. The characterization involves an order embedding of Conway’s normal play games, and we call our class the universe of Guaranteed scoring games. Also, we give a theorem for comparing guaranteed games with scores (numbers) which extends Ettinger’s work on Dicot scoring games. 相似文献
57.
Malte Braack Martin F. Quaas Benjamin Tews Boris Vexler 《Journal of Optimization Theory and Applications》2018,178(3):950-972
The behavior of a fishing fleet and its impact onto the biomass of fish can be described by a nonlinear parabolic diffusion–reaction equation. Looking for an optimal fishing strategy leads to a non-convex optimal control problem with a bilinear control action. In this work, we present such an optimal control formulation, prove its well-posedness and derive first- and second-order optimality conditions. These results provide a basis for tailored finite element discretization as well as for Newton type optimization algorithms. First numerical test problems show typical features as so-called No-Take-Zones and maximal fishing quota (total allowable catches) as parts of an optimal fishing strategy. 相似文献
58.
Arthur Baragar 《Geometriae Dedicata》2018,195(1):137-161
The Apollonian circle and sphere packings are well known objects that have attracted the attention of mathematicians throughout the ages. The historically natural generalization of the procedure for generating the packing breaks down in higher dimensions, as it leads to overlapping hyperspheres. There is, however, an alternative interpretation that allows one to extend the concept to higher dimensions and in a unique way. For relatively small dimensions (2 through at least 8), those packings can be thought of as ample cones for classes of K3 surfaces. We describe the packings in some detail for dimensions 4 (with plenty of pictures), 5, and 6. 相似文献
59.
Dariusz Zagrodny 《Journal of Optimization Theory and Applications》2018,178(2):411-423
In this paper, results on the strong convergence of subgradients of convex functions along a given direction are presented; that is, the relative compactness (with respect to the norm) of the union of subdifferentials of a convex function along a given direction is investigated. 相似文献
60.
The minor relation of functions is generalized to multisorted functions. Pippenger’s Galois theory for minor-closed sets of functions is extended to multisorted functions and multisorted relation pairs. Reflections of minor-closed sets are again minor-closed, and the effect of reflections on the invariant relation pairs of minor-closed sets of multisorted functions is described. 相似文献