Local and inter-area oscillations in bulk power systems are typically identified using spatial profiles of poorly damped modes, and they are mitigated via carefully tuned decentralized controllers. In this paper, we employ non-modal tools to analyze and control inter-area oscillations. Our inputoutput analysis examines power spectral density and variance amplification of stochastically forced systems and offers new insights relative to modal approaches. To improve upon the limitations of conventional wide-area control strategies, we also study the problem of signal selection and optimal design of sparse and block-sparse wide-area controllers. In our design, we preserve rotational symmetry of the power system by allowing only relative angle measurements in the distributed controllers. For the IEEE 39 New England model, we examine performance tradeoffs and robustness of different control architectures and show that optimal retuning of fully-decentralized control strategies can effectively guard against local and inter-area oscillations.

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Lead-free ferroelectric un-doped and doped K0.5Na0.5NbO3 (KNN) films with different amounts of manganese (Mn) were prepared by a chemical solution deposition method. The thicknesses of all films are about 1.6 μm. Their phase, microstructure, leakage current behavior, and electrical properties were investigated. With increasing the amounts of Mn, the crystallinity became worse. Fortunately, the electrical properties were improved due to the decreased leakage current density after Mn-doping. The study on leakage behaviors shows that the dominant conduction mechanism at low electric field in the un-doped KNN film is ohmic mode and that at high electric field is space-charge-limited and Pool-Frenkel emission. After Mn doping, the dominant conduction mechanism at high electric field of KNN films changed single space-charge-limited. However, the introduction of higher amount of Mn into the KNN film would lead to a changed conduction mechanism from space-charge-limited to ohmic mode. Consequently, there exists an optimal amount of Mn doping of 2.0 mol. %. The 2.0 mol. % Mn doped KNN film shows the lowest leakage current density and the best electrical properties. With the secondary ion mass spectroscopies and x-ray photoelectron spectroscopy analyses, the homogeneous distribution in the KNN films and entrance of Mn element in the lattice of KNN perovskite structure were also confirmed.

In this study, we investigated the therapeutic effect of artemisinin (Art) on lupus nephritis mice and its mechanisms by comparing the differences between lupus nephritis (LN) mice given Art and control mice in molecular biology, immunohistochemistry, and histopathology. The results showed that Art could remarkably relieve the symptoms, decrease the level of urine protein/24 h, and alleviate pathological renal lesions. The differences among the four groups in the expression of the NF-kBp65 protein, nuclear factor-kB (NF-kB) activity, and the expression of transforming growth factor-b1 (TGF-b1) mRNA in renal tissue suggested that Art can lower the serum levels of tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6) and inhibit the expression of the NF-kBp65 protein and NF-kB and TGF-b1 mRNA in the renal tissues of LN mice. These results proved that it is reliable and effective to use Art to treat LN mice, and its therapeutic mechanisms should closely be related to the fact that Art can obviously decrease the serum levels of TNF-a and IL-6 and down-regulate the expression of the NF-kBp65 protein and NF-kB and TGF-b1 mRNA in renal tissues.

Optimal control problems in systems with symmetries and consensus/synchronization networks are characterized by structural constraints that arise either from the underlying group structure or the lack of the absolute measurements for a part of the state vector. Our objective is to design controller structures and resulting control strategies that utilize limited information exchange between subsystems in large-scale networks. To obtain controllers with low communication requirements, we seek solutions to regularized versions of the H 2 optimal control problem. Non-smooth regularization terms are introduced to tradeoff network performance with sparsity of the feedback-gain matrix. In contrast to earlier results, our framework allows the state-space representations that are used to quantify the system's performance and sparsity of the controller to be expressed in different sets of coordinates. We show how alternating direction method of multipliers can be leveraged to exploit the underlying structure and compute sparsity-promoting controllers. In particular, for spatially-invariant systems, the computational complexity of our algorithms scales linearly with the number of subsystems. We also identify a class of optimal control problems that can be cast as semidefinite programs and provide an example to illustrate our developments.

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An argon atmospheric pressure plasma jet was employed to treat L929 murine fibroblasts cultured in vitro. Experimental results showed that, compared with the control cells, the treatment of fibroblasts with 15 s of plasma led to a significant increase of cell viability and collagen synthesis, while the treatment of 25 s plasma resulted in a remarkable decrease. Exploration of related mechanisms suggested that cold plasma could up-regulate CyclinD1 gene expression and down-regulate p27 gene expression at a low dose, while it could down-regulate CyclinD1 expression and up-regulate p27 expression at a higher dose, thus altering the cell cycle progression, and then affecting cell viability and collagen synthesis of fibroblasts.