143 research outputs found

    Reduced-order washout controllers stabilizing uncertain equilibrium points

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    金沢大学理工研究域電子情報学系We consider a local stabilization problem of an uncertain equilibrium point existed in a nonlinear continuous-time system by a finite-dimensional dynamical state feedback controller. In previous research, it is investigated that steady-state blocking zeros of the stabilizing controller play an important role. Such a controller is called a washout controller. In this paper, we develop a design method for reduced-order washout controllers whose order is less than the plant\u27s order. Additionally, we also consider a local stabilization problem of an uncertain fixed point of a given discrete-time system. © 2007 IEEE

    Strong-coupling theory of superconductivity in a degenerate Hubbard model

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    In order to discuss superconductivity in orbital degenerate systems, a microscopic Hamiltonian is introduced. Based on the degenerate model, a strong-coupling theory of superconductivity is developed within the fluctuation exchange (FLEX) approximation where spin and orbital fluctuations, spectra of electron, and superconducting gap function are self-consistently determined. Applying the FLEX approximation to the orbital degenerate model, it is shown that the dx2y2d_{x^2-y^2}-wave superconducting phase is induced by increasing the orbital splitting energy which leads to the development and suppression of the spin and orbital fluctuations, respectively. It is proposed that the orbital splitting energy is a controlling parameter changing from the paramagnetic to the antiferromagnetic phase with the dx2y2d_{x^2-y^2}-wave superconducting phase in between.Comment: 4 figures, submitted to PR

    Washout Control for Manual Operations

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    It is known that limitations of human accuracy in manual manipulation hinder the quality of work performed by human operators of manual control systems. Indeed, movements of operators are apt to cause undesirable vibrations in manual control systems. In this paper, we propose a new operator-support-control scheme for suppressing harmful oscillatory motions in such systems without disturbing human operator\u27s manipulation. The proposed scheme is based on the fact that steady-state blocking zeros of a feedback controller do not affect the steady-state control input. A finite-dimensional feedback controller with steady-state blocking zeros, called a washout controller in this paper, plays the central role in support for operator\u27s manipulation. However, the dynamics of a manual control system may become different significantly from its initial model used for the design of an initial washout controller when it is applied to the manual control system. Such difference can result in poor performance of operator-support-control. In order to improve it, an iterative procedure is presented for re-design of washout controllers based on closed-loop subspace identification. Closed-loop identification is performed to brush up the model for the control design, and then a more sophisticated washout controller is obtained using the identified model. The effectiveness of the proposed scheme is demonstrated by an experiment on manual control of an inverted pendulum. © 2007 EUCA

    Washout control for manual operations

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    金沢大学理工研究域電子情報学系It is known that limitations of human accuracy in manual manipulation hinder the quality of work performed by human operators of manual control systems. Indeed, movements of operators are apt to cause undesirable vibrations in manual control systems. In this paper, we propose a new operator-support control scheme for suppressing harmful oscillatory motions in such systems without disturbing human operator\u27s manipulation. The proposed scheme is based on the fact that steady-state blocking zeros of a feedback controller do not affect the steady-state control input. A finite-dimensional feedback controller with steady-state blocking zeros, called a washout controller in this paper, plays the central role in support for operator\u27s manipulation. However, the dynamics of a manual control system may become different significantly from its initial model used for the design of an initial washout controller when it is applied to the manual control system. Such difference can result in poor performance of operator-support control. In order to improve it, an iterative procedure is presented for redesign of washout controllers based on closed-loop subspace identification. Closed-loop identification is performed to refine the model for the control design, and then a more sophisticated washout controller is obtained using the identified model. The effectiveness of the proposed scheme is demonstrated by an experiment on manual control of an inverted pendulum. © 2008 IEEE

    Complex of human neutrophil elastase with 1/2SLPI

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    The 1/2SLPI and HNE complex structure was solved at 1.7 Å resolution and compared with the interaction mechanism of elafin

    Inkjet printed intelligent reflecting surface (IRS) for indoor applications

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    A passive, low-cost, paper-based intelligent reflecting surface (IRS) is designed to reflect a signal in a desired direction to overcome non-line-of-sight scenarios in indoor environments. The IRS is fabricated using conductive silver ink printed on a paper with a specific nanoparticle arrangement, yielding a cost effective paper-based IRS that can easily be mass-produced. Full-wave numerical simulation results were consistent with measurements results, demonstrating the IRS's ability to reflect incident wave into a desired nonspecular direction based on the inkjet-printed design and materials

    Anthropogenic Pu distribution in Tropical East Pacific

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    金沢大学理工研究域物質化学系The geographical distribution of the anthropogenic radionuclides 238Pu and 239+240Pu in the Tropical East Pacific in 2003 was studied from the viewpoint of material migration. We measured the contents of Pu isotopes in seawater and in sediment from the sea bottom. The distributions of Pu isotopes, together with those of coexisting nitrate and phosphate species and dissolved oxygen, are discussed in relation to the potential temperature and potential density (sigma-θ). The Pu contents in sediment samples were compared with those in the seawater. Horizontal migration across the Equator from north to south was investigated at depths down to ~800m in the eastern Pacific. The Pu distribution at 0-400m correlated well with the distribution of potential temperature. Maximum Pu levels were observed in the subsurface layer at 600-800m, corresponding to the depth where sigma-θ≈27.0. It is suggested that the Pu distribution depends on the structure of the water mass and the particular temperature and salinity. The water column/sediment column inventory ratio and the vertical distribution of Pu may reflect the efficiency of scavenging in the relevant water areas. © 2011 Elsevier B.V

    Stripe formation in high-Tc superconductors

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    The non-uniform ground state of the two-dimensional three-band Hubbard model for the oxide high-Tc superconductors is investigated using a variational Monte Carlo method. We examine the effect produced by holes doped into the antiferromagnetic (AF) background in the underdoped region. It is shown that the AF state with spin modulations and stripes is stabilized du to holes travelling in the CuO plane. The structures of the modulated AF spins are dependent upon the parameters used in the model. The effect of the boundary conditions is reduced for larger systems. We show that there is a region where incommensurability is proportional to the hole density. Our results give a consistent description of stripes observed by the neutron- scattering experiments based on the three-band model for CuO plane.Comment: 8 pages, 9 figure

    Microscopic Aspects of Multipole Properties of Filled Skutterudites

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    We discuss low-temperature multipole states of Nd-based filled skutterudites by analyzing a multiorbital Anderson model with the use of a numerical renormalization group method. In order to determine the multipole state, we take a procedure to maximize the multipole susceptibility matrix. Then, it is found that the dominant multipole state is characterized by the mixture of 4u magnetic and 5u octupole moments. The secondary state is specified by 2u octupole. When we further take into account the coupling between ff electrons in degenerate Γ67\Gamma_{67}^{-} (eue_{\rm u}) orbitals and dynamical Jahn-Teller phonons with EgE_{\rm g} symmetry, quadrupole fluctuations become significant at low temperatures in the mixed multipole state with 4u magnetic and 5u octupole moments. Finally, we briefly discuss possible relevance of the present results to actual Nd-based filled skutterudite compounds.Comment: 6 pages, 3 figures. To appear in the Proceedings of the 17th International Conference on Magnetism (ICM2006

    Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex

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    In the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement
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