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991.
Martina Chirilus-Bruckner Guido Schneider Hannes Uecker 《Journal of Mathematical Analysis and Applications》2008,347(1):304-314
We give a detailed analysis of the interaction of two NLS-described wave packets with different carrier waves for a nonlinear wave equation. By separating the internal dynamics of each wave packet from the dynamics caused by the interaction we prove that there is almost no interaction of such wave packets. We also prove the validity of a formula for the envelope shift caused by the interaction of the wave packets. 相似文献
992.
993.
994.
J. Repper P. Link M. Hofmann C. Krempaszky W. Petry E. Werner 《Applied Physics A: Materials Science & Processing》2010,99(3):565-569
The linear energy–momentum relation results in more high-energy electrons in 2D (two-dimensional) graphene FETs (field-effect
transistor) than those in silicon FETs that features parabolic energy–momentum relation if the same surface electron density
has been assumed in all FETs. The numerical calculations demonstrate that, under such assumption, the gate leakage currents
in graphene FETs are much larger than that in silicon FETs. The results illustrate that if the conduction band offset between
graphene and gate oxide is lower than 3.55 eV, the gate leakage currents in graphene electronics are more significant than
those in the silicon electronics. 相似文献
995.
996.
Guido Fubini 《Rendiconti del Circolo Matematico di Palermo》1916,42(1):135-154
Let Ω ? ? n be a convex bounded open set, of class\(C^2 ,Q_\tau = \Omega \times \left[ {\tau ,\tau + T} \right],\tau \in \mathbb{R},T > 0.\). LetB be a linear continuous operator ofL 2Ω ? ? N inL 2Ω ? ? N . It is shown that if\(f \in L^2 (Q_\tau ,\mathbb{R}^N )\) then there exists a unique solution of the problem:\(u \in W^{2,1} (Q_\tau ,\mathbb{R}^N ),\alpha (x,t,H(u)) - \frac{{\partial u}}{{\partial t}} = f(x,t)\), in\(Q_\tau \), such thatu(x,t)=B u(x, τ+T) in Ω, wherea(x, t, ζ) is misurable in(x,t), continuous in ζ,a(x,t, 0)=0, and verifies condition (A). IfB=Id this is the classical periodic problem. If moreovera(x,t,ζ)=a(x,t+T, ζ) anda(x,t, H (Bu))=B a(x,t,H (u)) ?t ∈ ?, the analogous problem in Ω × ? is studied. 相似文献
997.
The positivity-preserving property for the inverse of the biharmonic operator under Steklov boundary conditions is studied.
It is shown that this property is quite sensitive to the parameter involved in the boundary condition. Moreover, positivity
of the Steklov boundary value problem is linked with positivity under boundary conditions of Navier and Dirichlet type. 相似文献
998.
Guido W. Fuchs 《Annalen der Physik》2013,525(12):A191-A193
999.
Berthold T von Gromoff ED Santabarbara S Stehle P Link G Poluektov OG Heathcote P Beck CF Thurnauer MC Kothe G 《Journal of the American Chemical Society》2012,134(12):5563-5576
Crystallographic models of photosystem I (PS I) highlight a symmetrical arrangement of the electron transfer cofactors which are organized in two parallel branches (A, B) relative to a pseudo-C2 symmetry axis that is perpendicular to the membrane plane. Here, we explore the electron transfer pathways of PS I in whole cells of the deuterated green alga Chlamydomonas reinhardtii using high-time-resolution electron paramagnetic resonance (EPR) at cryogenic temperatures. Particular emphasis is given to quantum oscillations detectable in the tertiary radical pairs P700(+)A1A(-) and P700(+)A1B(-) of the electron transfer chain. Results are presented first for the deuterated site-directed mutant PsaA-M684H in which electron transfer beyond the primary electron acceptor A0A on the PsaA branch of electron transfer is impaired. Analysis of the quantum oscillations, observed in a two-dimensional Q-band (34 GHz) EPR experiment, provides the geometry of the B-side radical pair. The orientation of the g tensor of P700(+) in an external reference system is adapted from a time-resolved multifrequency EPR study of deuterated and 15N-substituted cyanobacteria (Link, G.; Berthold, T.; Bechtold, M.; Weidner, J.-U.; Ohmes, E.; Tang, J.; Poluektov, O.; Utschig, L.; Schlesselman, S. L.; Thurnauer, M. C.; Kothe, G. J. Am. Chem. Soc. 2001, 123, 4211-4222). Thus, we obtain the three-dimensional structure of the B-side radical pair following photoexcitation of PS I in its native membrane. The new structure describes the position and orientation of the reduced B-side quinone A1B(-) on a nanosecond time scale after light-induced charge separation. Furthermore, we present results for deuterated wild-type cells of C. reinhardtii demonstrating that both radical pairs P700(+)A1A(-) and P700(+)A1B(-) participate in the electron transfer process according to a mole ratio of 0.71/0.29 in favor of P700(+)A1A(-). A detailed comparison reveals different orientations of A1A(-) and A1B(-) in their respective binding sites such that formation of a strong hydrogen bond from A1(-) to the protein backbone is possible only in the case of A1A(-). We suggest that this is relevant to the rates of forward electron transfer from A1A(-) or A1B(-) to the iron-sulfur center F(X), which differ by a factor of 10. Thus, the present study sheds new light on the orientation of the phylloquinone acceptors in their binding pockets in PS I and the effect this has on function. 相似文献
1000.
A self-assembled cage compound consisting of four concave ligands and two square-planar-coordinated Pd(II) ions was found to quantitatively encapsulate a hexamolybdate dianion [Mo(6)O(19)](2-) in solution. The addition of 1 equiv more of [Mo(6)O(19)](2-) to the inclusion complex resulted in the formation of a precipitate from which single crystals were grown. X-ray analysis showed that a structural conversion had taken place upon crystallization: one hexamolybdate anion was found to be wrapped in a chiral, cyclic arrangement of three ligands in the absence of any Pd(II) ions to give a compound of the formula {[Mo(6)O(19)](2-)@(ligand)(3)+2H(+)}. We postulate the stabilization of this arrangement by attractive C-H···O and CF(3)-pyridine interactions. 相似文献