Deposition of YBCO thin films on silver substrate via a fluorine-free sol-gel synthesis

To further develop grain-textured YBCO thin films for conductor development, we deposited, via a fluorine-free sol-gel synthesis, YBCO thin films on non-textured silver substrate. The interface structures were studied by both x-ray diffraction (XRD) and transmission electron microscopy (HRTEM). XRD data indicated that the YBCO films on silver substrate exhibited c-axis grain orientations. Experimental details are reported on the sol-gel synthesis chemistry and XRD and HRTEM characterization of the YBCO thin films. © 2002 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87877/2/654_1.pd

Multiphysics vibration FE model of piezoelectric macro fibre composite on carbon fibre composite structures

This paper presents a finite element (FE) model developed using commercial FE software COMSOL to simulate the multiphysical process of pieozoelectric vibration energy harvesting (PVEH), involving the dynamic mechanical and electrical behaviours of piezoelectric macro fibre composite (MFC) on carbon fibre composite structures. The integration of MFC enables energy harvesting, sensing and actuation capabilities, with applications found in aerospace, automotive and renewable energy. There is an existing gap in the literature on modelling the dynamic response of PVEH in relation to real-world vibration data. Most simulations were either semi-analytical MATLAB models that are geometry unspecific, or basic FE simulations limited to sinusoidal analysis. However, the use of representative environment vibration data is crucial to predict practical behaviour for industrial development. Piezoelectric device physics involving solid mechanics and electrostatics were combined with electrical circuit defined in this FE model. The structure was dynamically excited by interpolated vibration data files, while orthotropic material properties for MFC and carbon fibre composite were individually defined for accuracy. The simulation results were validated by experiments with <10﹪ deviation, providing confidence for the proposed multiphysical FE model to design and optimise PVEH smart composite structures

Surface Adjustment Strategy for a Large Radio Telescope with Adjustable Dual Reflectors

With the development of large-aperture and high-frequency radio telescopes, a surface adjustment procedure for the compensation of surface deformations has become of great importance. In this study, an innovative surface adjustment strategy is proposed to achieve an automated adjustment for the large radio telescope with adjustable dual reflectors. In the proposed strategy, a high-precision and long-distance measurement instrument is adopted and installed on the back of the sub-reflector to measure the distances and elevation angles of the target points on the main reflector. Here, two surface adjustment purposes are discussed. The first purpose is to ensure that the main reflector and sub-reflector are always positioned at their ideal locations during operation. The second purpose is to adjust the main reflector to the location of the best fitting reflector, and the sub-reflector to the focus of the best fitting reflector. Next, the calculation procedures for the adjustments of the main reflector and the sub-reflector are discussed in detail, and corresponding simulations are carried out to verify the proposed method. The results show that the proposed strategy is effective. This study can provide helpful guidance for the design of automated surface adjustments for large telescopes

Interface structure of YBa2Cu3Ox thin films prepared by a non-fluorine sol–gel route on a single-domain substrate

In our previous work, we have shown that a single-domain YBa2Cu3Ox (YBCO) exhibits a low surface resistance. However, the second phase Y2BaCuO5 (211) precipitates inevitably as a result of peritectic reaction. These 211 particles are potential sources of RF losses, which need to be eliminated. In this study, a non-fluorine sol–gel synthesis was developed to deposit a YBCO thin film on the surface of single-domain YBCO. The deposited YBCO thin film entirely covered the 211 particles. The interface structure was studied by high-resolution transmission electron microscopy. The experimental results on sol–gel synthesis and thin film characterization are reported. Also discussed is the underlying mechanism of film growth on single-domain YBCO.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48990/2/u20504.pd

Human pluripotent stem cell-derived mesenchymal stem cells prevent allergic airway inflammation in mice.

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UKF Based filters in INS/GPS integrated navigation systems: Novel application results

The filtering problem in the INS/GPS integrated navigation system is investigated in this study. Firstly, the nonlinear model of the INS/GPS integrated navigation system is proposed. Then the applications of the EKF, the UKF and the modified adaptive UKF are put in practice based on the model. A sample set of computer simulation results for the three filter algorithms, obtained by using MATLAB platform, are given to illustrate the effectiveness of the proposed algorithm with regard to the convergence rate and the estimation precision. Copyright © 2007 IFAC Keywords: Adaptive signal processing, integrated navigation system, INS/GPS, trace tracking, unscented Kalman filter, nonlinear control system