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21.
22.
Global existence of regular solutions for a nonlinear Schroedinger–Chern–Simons system of equations on a two-dimensional compact Riemannian manifold is proved. 相似文献
23.
2-Cyano cyanothioformanilide 3a reacts with triphenylphosphine in the presence of water to give 2-(cyanomethyleneamino)benzonitrile 4a, 2-(cyanomethylamino)benzonitrile 5, 3-aminoindole-2-carbonitrile 2a and (2-cyanoindol-3-yl)iminotriphenylphosphorane 6a. In the presence of p-toluenesulfonic acid in MeOH the reaction between 2-cyano cyanothioformanilide 3a and triphenylphosphine (2 equiv) gives 3-aminoindole-2-carbonitrile 2a in 90% yield. Under the same conditions 2-(cyanomethyleneamino)benzonitrile 4a gives anthranilonitrile 8a, 3-aminoindole-2-carbonitrile 2a and N-(2-cyanophenyl)formamide 9. In addition, substituted 2-cyano cyanothioformanilides 3b-f react with triphenylphosphine and p-toluenesulfonic acid in MeOH to give 3-aminoindole-2-carbonitriles 2b-f in 63-75% yields. Under analogous conditions 2-cyano-4,5-dimethoxyphenyl cyanothioformanilide 2g gives only 4,5-dimethoxyanthranilonitrile 8g and 4,6,7-trimethoxyquinazoline-2-carbonitrile 14g, but in refluxing dry PhMe in the absence of p-toluenesulfonic acid 2-cyano-4,5-dimethoxyphenyl cyanothioformanilide 3g, (2-cyano-5,6-dimethoxyindol-3-yl)iminotriphenylphosphorane 6g and 2-(cyanomethyleneamino)-4,5-dimethoxybenzonitrile 4g are obtained. The structure of 2-(cyanomethyleneamino)-4,5-dimethoxybenzonitrile 4g is supported unambiguously via independent synthesis and comparison to the isomeric 6,7-dimethoxyquinazoline-2-carbonitrile 15. All new compounds are fully characterised and a tentative mechanism for the transformation of 2-cyano cyanothioformanilides to indoles is proposed. 相似文献
24.
Jörg Petrasch Sophia Haussener 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(9):1450-1459
The mathematical formulation of the continuum approach to radiative transfer modeling in two-phase semi-transparent media is numerically validated by comparing radiative fluxes computed by (i) direct, discrete-scale and (ii) continuum-scale approaches. The analysis is based on geometrical optics. The discrete-scale approach uses the Monte Carlo ray-tracing applied directly to real 3D geometry measured by computed tomography. The continuum-scale approach is based on a set of continuum-scale radiative transfer equations and associated radiative properties, and employs the Monte Carlo ray-tracing for computations of radiative fluxes and for computations of the radiative properties. The model two-phase media are reticulate porous ceramics and a particle packed bed, each composed of semitransparent solid and fluid phases. The results obtained by the two approaches are in good agreement within the limits of statistical uncertainty. The continuum-scale approach leads to a reduction in computational time by approximately one order of magnitude, and is therefore suited to treat radiative transfer problems in two-phase media in a wide range of engineering applications. 相似文献
25.
Spatzek S Greilich A Economou SE Varwig S Schwan A Yakovlev DR Reuter D Wieck AD Reinecke TL Bayer M 《Physical review letters》2011,107(13):137402
Coherent interactions between spins in quantum dots are a key requirement for quantum gates. We have performed pump-probe experiments in which pulsed lasers emitting at different photon energies manipulate two distinct subsets of electron spins within an inhomogeneous InGaAs quantum dot ensemble. The spin dynamics are monitored through their precession about an external magnetic field. These measurements demonstrate spin precession phase shifts and modulations of the magnitude of one subset of oriented spins after optical orientation of the second subset. The observations are consistent with results from a model using a Heisenberg-like interaction with μeV strength. 相似文献
26.
Gerhard Post Jeffrey H. Kingston Samad Ahmadi Sophia Daskalaki Christos Gogos Jari Kyngas Cimmo Nurmi Nysret Musliu Nelishia Pillay Haroldo Santos Andrea Schaerf 《Annals of Operations Research》2014,218(1):295-301
We present the progress on the benchmarking project for high school timetabling that was introduced at PATAT 2008. In particular, we announce the High School Timetabling Archive XHSTT-2011 with 21 instances from 8 countries and an evaluator capable of checking the syntax of instances and evaluating the solutions. 相似文献
27.
Sophia Demoulini David M. A. Stuart 《Calculus of Variations and Partial Differential Equations》2007,30(4):523-546
We prove existence and regularity of critical points of arbitrary degree for a generalised harmonic map problem, in which
there is an additional nonlocal polyconvex term in the energy, heuristically of the same order as the Dirichlet term. The
proof of regularity hinges upon a special nonlinear structure in the Euler–Lagrange equation similar to that possessed by
the harmonic map equation. The functional is of a type appearing in certain models of the quantum Hall effect describing nonlocal
Skyrmions. 相似文献
28.
Jeffrey J. Jackson Dr. Hiroyuki Kobayashi Sophia D. Steffens Prof. Dr. Armen Zakarian 《Angewandte Chemie (International ed. in English)》2015,54(34):9971-9975
The asymmetric synthesis of dragmacidin D ( 1 ) was completed in 10 steps. Its sole stereocenter was set by using direct asymmetric alkylation enabled by a C2‐symmetric tetramine and lithium N‐(trimethylsilyl)‐tert‐butylamide as the enolization reagent. A central Larock indole synthesis was employed in a convergent assembly of the heterocyclic subunits. The stereochemical evidence from this work strongly supports the predicted S configuration at the 6′′′ position, which is consistent with other members of the dragmacidin family of natural products. 相似文献
29.
Strong Direct Magnetic Coupling in a Dinuclear CoII Tetrazine Radical Single‐Molecule Magnet
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Toby J. Woods Dr. Maria Fernanda Ballesteros‐Rivas Sergei M. Ostrovsky Andrew V. Palii Oleg S. Reu Sophia I. Klokishner Dr. Kim R. Dunbar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10302-10305
The ligand‐centered radical complex [(CoTPMA)2‐μ‐bmtz.?](O3SCF3)3 ? CH3CN (bmtz=3,6‐bis(2′‐pyrimidyl)‐1,2,4,5‐tetrazine, TPMA=tris‐(2‐pyridylmethyl)amine) has been synthesized from the neutral bmtz precursor. Single‐crystal X‐ray diffraction studies have confirmed the presence of the ligand‐centered radical. The CoII complex exhibits slow paramagnetic relaxation in an applied DC field with a barrier to spin reversal of 39 K. This behavior is a result of strong antiferromagnetic metal–radical coupling combined with positive axial and strong rhombic anisotropic contributions from the CoII ions. 相似文献
30.
A microscopic approach to the problem of cooperative spin crossover in the [MnL2]NO3 crystal, which contains Mn(III) ions as structural units, is elaborated on, and the main mechanisms governing this effect are revealed. The proposed model also takes into account the splitting of the low-spin 3T1 (t(2)(4)) and high-spin 5E (t(2)(3)e) terms by the low-symmetry crystal field. The low-spin → high-spin transition has been considered as a cooperative phenomenon driven by interaction of the electronic shells of the Mn(III) ions with the all-around full-symmetric deformation that is extended over the crystal lattice via the acoustic phonon field. The model well explains the observed thermal dependencies of the magnetic susceptibility and the effective magnetic moment. 相似文献