The Mg 3pns (n =10-18) and 3pnd (n =9-40) doubly excited J =1 autoionizing states have been observed experimentally using an isolated-core excitation method with stepwise laser excitation.Linearly polarized laser light excites the 3pnd J = 1 and J =3 states, as well as the 3pns J = 1 states. Our previous study of the J =3 states enables the J =1 states in the 3pnd spectra to be identified.We have also calculated the spectra from a reaction matrix, and the agreement between theory and experiment is generally excellent. Differences between the J=1 and J=3 features are discussed and qualitatively explained in terms of semiclassical arguments. Additionally, energies of the 3sns 'So (n = 11 -22) Rydberg levels are reported.

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A distributed control strategy is developed to control the output of multiple distributed generators (DGs) in a coordinated fashion such that these generators develop into a virtual power plant (VPP) in a distribution network. To this end, cooperative control methodology from network control theory is used to make the VPP converge and operate at an optimal output, which is determined by the DGs' costs and the necessary service assigned by the distribution network. For each DG, the strategy only requires information from its neighbouring units, making communication networks (CNs) among the DGs simple and robust. A set of sufficient conditions under which the proposed method is valid are provided. It is shown that the proposed strategy has the advantages that the corresponding CNs are local and there is no central station collecting global information from the DGs. These features enable the VPP to have both self-organising and adaptive coordination properties. The proposed method is simulated using the IEEE standard 34-bus distribution network.

The speed regulation problem of permanent magnet synchronous motor (PMSM) system is investigated under a non-cascade structure. Despite its superiority in straightforward control design, simple parameter adjustment and satisfying system dynamic performance, the structure brings two problems: the overcurrent protection and unmatched disturbance rejection. Under this structure, the current cannot any more be restricted by a reference value, and ought to be constrained within a certain range to ensure the circuit safety. Besides, unmatched disturbances, mainly caused by external load torques, may result in undesired interference and violate the constraint requirement since they affect the current directly via the same channel. Toward that end, a novel current-constrained control algorithm is designed to tackle the current constraint and unmatched disturbances simultaneously. A disturbance observer (DOB) is utilized for unmatched disturbance estimation. A constraint coping mechanism is constructed to restrict the current. Then, a key nonlinear item is proposed by augmenting the disturbance estimation and the constrained current. Finally, a composite controller is proposed with concise structure and rigorous closed-loop stability analysis. Numerical and experimental tests further validate that the proposed control approach achieves promising speed tracking performance and guarantees the current constraint in the presence of unmatched disturbances.

We have measured the angular distributions of electrons ejected from doubly excited autoionizing Rydberg 3pnd J =1 and 3 states of magnesium, where n =10-18. To excite the aligned 3snd 'D2 states of Mg, we used two dye lasers crossed with an atomic beam. A third laser, linearly polarized in the same direction as the other two, excited the atoms in the 3snd states to the 3pnd states. The angular distributions of ejected electrons are given by dtrldQ=+"akPI, (cos8)i, where k =0,2, 4, 6. We measured the angular distribution parameters aj, as a function of the energy of the third laser photon using an electron detector and a Mg ion detector. We compare our results with the predictions of an 8-matrix multichannel quantum-defect theory. We find good agreement between experiment and theory.PACS number(s): 34.50. Lf, 32.80.Rm, 32.80.Dz, 82.50.Fv