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991.
<正>1 Introduction and Main Results In this paper,we study the dynamics of compressible viscous charged particles consisting of two-species particles (e.g.,ions and electrons) under the influence of the self-consistent electrostatic potential force in semiconductor device or plasma physics (cf.[1,6]) which is modeled by the compressible Navier-Stokes-Poisson system (called NSP system in the sequel for simplicity). 相似文献
992.
993.
利用紫外-可见光谱和荧光光谱手段研究了四苯基卟啉钴(CoTPP)对苯胺、乙二胺和二乙胺的超分子固定用于脱除SO2. 紫外-可见光谱表明CoTPP与三种胺作用后生成CoTPP-胺配合物,Soret吸收带发生红移. 当通入SO2后,SO2与胺的作用强于CoTPP与胺的作用,CoTPP-胺配合物释放出CoTPP,CoTPP 在胺法脱硫过程中起到胺固定作用. 荧光光谱表明CoTPP与三种胺作用形成1:1的分子配合物,且为熵驱动反应. CoTPP与苯胺和二乙胺作用为吸热反应,CoTPP与乙二胺作用为放热反应. 相似文献
994.
995.
The observation and study of nonlinear dynamical systems has been gaining popularity over years in different fields. The intrinsic complexity of their dynamics defies many existing tools based on individual orbits, while the Koopman operator governs evolution of functions defined in phase space and is thus focused on ensembles of orbits, which provides an alternative approach to investigate global features of system dynamics prescribed by spectral properties of the operator. However, it is difficult to identify and represent the most relevant eigenfunctions in practice. Here, combined with the Koopman analysis, a neural network is designed to achieve the reconstruction and evolution of complex dynamical systems. By invoking the error minimization, a fundamental set of Koopman eigenfunctions are derived, which may reproduce the input dynamics through a nonlinear transformation provided by the neural network. The corresponding eigenvalues are also directly extracted by the specific evolutionary structure built in. 相似文献
996.
A quantum router is one of the essential elements in the quantum network. Conventional routers only direct a single photon from one quantum channel into another. Here, we propose a few-photon router. The active element of the router is a single qubit chirally coupled to two independent waveguides simultaneously, where each waveguide mode provides a quantum channel. By introducing the operators of the scatter-free space and the controllable space, the output state of the one-photon and two-photon scattering are derived analytically. It is found that the qubit can direct one and two photons from one port of the incident waveguide to an arbitrarily selected port of the other waveguide with unity, respectively. However, two photons cannot be simultaneously routed to the same port due to the anti-bunch effect. 相似文献
997.
998.
In this paper, the problem of adaptive tracking control in networked nonidentical Lagrange systems is investigated via backstepping schemes. Two distributed tracking control algorithms are designed for directed network topology graph with a spanning tree, where both the leader’s position and its velocity are assumed to be varying. Some generic criteria for adaptive tracking control algorithms with uncertain external disturbance and parametric uncertainties are presented. It is shown that the proposed algorithms only require a subset of the followers access to leader’s position. Furthermore, the adaptive control algorithm for uncertain external disturbance systems is robust, and it can avoid online measurement for neighbors’ velocities and efficiently eliminate the chattering during tracking. The results show that all followers can track the leader’s dynamics. Two examples and their simulations show the effectiveness of the proposed algorithms. 相似文献
999.
1000.
An der Lan L Bartl P Leidlmair C Jochum R Denifl S Echt O Scheier P 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(14):4411-4418
Helium atoms bind strongly to alkali cations which, when embedded in liquid helium, form so-called snowballs. Calculations suggest that helium atoms in the first solvation layer of these snowballs form rigid structures and that their number (n) is well defined, especially for the lighter alkalis. However, experiments have so far failed to accurately determine values of n. We present high-resolution mass spectra of Na(+)He(n), K(+)He(n), Na(2)(+)He(n) and K(2)(+)He(n), formed by electron ionization of doped helium droplets; the data allow for a critical comparison with several theoretical studies. For sodium and potassium monomers the spectra indicate that the value of n is slightly smaller than calculated. Na(2)(+)He(n) displays two distinct anomalies at n=2 and n=6, in agreement with theory; dissociation energies derived from experiment closely track theoretical values. K(2)(+)He(n) distributions are fairly featureless, which also agrees with predictions. 相似文献