Exponential stability of variable coefficients Rayleigh beams under boundary feedback controls: A Riesz basis approach

In this paper, we study the boundary stabilizing feedback control problem of Rayleigh beams that have non-homogeneous spatial parameters. We show that no matter how non-homogeneous the Rayleigh beam is, as long as it has positive mass density, stiffness and mass moment of inertia, it can always be exponentially stabilized when the control parameters are properly chosen. The main steps are a detail asymptotic analysis of the spectrum of the system and the proving of that the generalized eigenfunctions of the feedback control system form a Riesz basis in the state Hilbert space. As a by-product, a conjecture in Guo (J. Optim. Theory Appl. 112(3) (2002) 529) is answered. © 2003 Elsevier B.V. All rights reserved.postprin

Exponential stabilization of laminated beams with structural damping and boundary feedback controls

We study the boundary stabilization of laminated beams with structural damping which describes the slip occurring at the interface of two-layered objects. By using an invertible matrix function with an eigenvalue parameter and an asymptotic technique for the first order matrix differential equation, we find out an explicit asymptotic formula for the matrix fundamental solutions and then carry out the asymptotic analyses for the eigenpairs. Furthermore, we prove that there is a sequence of generalized eigenfunctions that forms a Riesz basis in the state Hilbert space, and hence the spectrum determined growth condition holds. Furthermore, exponential stability of the closed-loop system can be deduced from the eigenvalue expressions. In particular, the semigroup generated by the system operator is a Co-group due to the fact that the three asymptotes of the spectrum are parallel to the imaginary axis. © 2005 Society for Industrial and Applied Mathematics.published_or_final_versio

Enabling Thin and Flexible Solid-State Composite Electrolytes by the Scalable Solution Process

All solid-state batteries (ASSBs) have the potential to deliver higher energy densities, wider operating temperature range, and improved safety compared with today's liquid-electrolyte-based batteries. However, of the various solid-state electrolyte (SSE) classes - polymers, sulfides, or oxides - none alone can deliver the combined properties of ionic conductivity, mechanical, and chemical stability needed to address scalability and commercialization challenges. While promising strategies to overcome these include the use of polymer/oxide or sulfide composites, there is still a lack of fundamental understanding between different SSE-polymer-solvent systems and its selection criteria. Here, we isolate various SSE-polymer-solvent systems and study their molecular level interactions by combining various characterization tools. With these findings, we introduce a suitable Li7P3S11SSE-SEBS polymer-xylene solvent combination that significantly reduces SSE thickness (∼50 μm). The SSE-polymer composite displays high room temperature conductivity (0.7 mS cm-1) and good stability with lithium metal by plating and stripping over 2000 h at 1.1 mAh cm-2. This study suggests the importance of understanding fundamental SSE-polymer-solvent interactions and provides a design strategy for scalable production of ASSBs

A Design of Robust Feedback Control for Flexible Robotic Mechanisms

We study flexible robotic arms that are free to rotate and bend in the horizontal plane but are stiff in vertical bending and torsion. A motor connected to the hinged end drives the arm to a prescribed target position and it is the aim of this paper to design boundary feedback controller to stabilize the arm once it reaches the atarget position. A distinct difficulty is the non-dissipativity that arises from the requirement that the designed feedback should retain 0 as an eigenvalue in order not to change the rigid body mode shape of the arm. On preserving this zero eigenvalue, we have successfully constructed a boundary feedback that is robustly stable with respect to the target position by showing it is exponentially stable there.published_or_final_versio

Asymptotic Frequency Distributions for Variable Coefficients Rayleigh Beams under Boundary Feedback Control

The analysis of the boundary damping rate for eigenmodes of a Rayleigh Beam with variable coefficients is usually difficult because explicit solution formula are hard to come by. In this paper, by using the estimating devices of [9], we can carry out an asymptotic analysis and conclude that there is a uniform damping rate for the high frequency modes. As a result, Riesz basis property and exponential stability can be deduced and a conjecture in [3] is settled.published_or_final_versio

Short circuit current improvement in planar heterojunction organic solar cells by multijunction charge transfer

A multijunction structure was applied on an organic photovoltaic (OPV) device for broadening the absorption spectrum and enhancing the power conversion efficiency through charge transfer process. By inserting the tris[4-(2-thienyl)]amine (TTPA) into a boron subphthalocyanine chloride (SubPc)/C 60 OPV device, the short circuit current density (J sc) showed a 47.5% increases from 3.05 to 4.50 mA/cm 2 in the bilayer planar heterojunction device, while the open circuit voltage (V oc) remained constant. Based on the single junction (TTPA/SubPc) device and photoluminescence absorption results, we confirmed both TTPA/SubPc and SubPc/C 60 junctions are contributing to the exciton dissociation process hence the efficiency enhancement. © 2012 American Institute of Physics.published_or_final_versio

No evidence for substrate accumulation in Parkinson brains with GBA mutations

To establish whether Parkinson's disease (PD) brains previously described to have decreased glucocerebrosidase activity exhibit accumulation of the lysosomal enzyme's substrate, glucosylceramide, or other changes in lipid composition

Trial-to-trial latency variability of somatosensory evoked potentials as a prognostic indicator for surgical management of cervical spondylotic myelopathy

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Concurrent adaptation to opposing visual displacements during an alternating movement.

It has been suggested that, during tasks in which subjects are exposed to a visual rotation of cursor feedback, alternating bimanual adaptation to opposing rotations is as rapid as unimanual adaptation to a single rotation (Bock et al. in Exp Brain Res 162:513–519, 2005). However, that experiment did not test strict alternation of the limbs but short alternate blocks of trials. We have therefore tested adaptation under alternate left/right hand movement with opposing rotations. It was clear that the left and right hand, within the alternating conditions, learnt to adapt to the opposing displacements at a similar rate suggesting that two adaptive states were formed concurrently. We suggest that the separate limbs are used as contextual cues to switch between the relevant adaptive states. However, we found that during online correction the alternating conditions had a significantly slower rate of adaptation in comparison to the unimanual conditions. Control conditions indicate that the results are not directly due the alternation between limbs or to the constant switching of vision between the two eyes. The negative interference may originate from the requirement to dissociate the visual information of these two alternating displacements to allow online control of the two arms