一种分块差分滤波器及其在仅有角度跟踪中的应用

为解决仅有角度跟踪时,目标估计受限于较大的初始估计误差和噪声统计特性未知的问题,提出了一种带有噪声智能统计功能的改进型分块差分滤波器.通过统计线性化方法得到了一种S-H智能噪声统计估值器,并用其优化传统分块噪声滤波器的测量更新步骤,实现了对未知过程和测量噪声的智能统计处理,通过迭代更新进一步提高了滤波器对于复杂非线性函数的适应能力.与目前几类主流的自适应滤波器性能相比,结果表明:对于具有线性系统模型和非线性测量模型的典型被动跟踪估计问题,针对较大的初始状态估计误差,所给出的滤波器能更好地完成系统噪声和测量噪声部分参数统计特性未知情况下的非线性估计任务,在保证计算量适中的同时有效地提高跟踪制导精度.     

Evaluating Emergency Response Capacity of Chemical Industrial Park Using an Hybrid Fuzzy AHP Method

This paper presents an expert-based fuzzy analytic hierarchy process （AHP） model for evaluating emergency response capacity of Chemical Industrial Park （ERCCIP） by jointly using an improved fuzzy preference programming （FPP） and 2-tuple fuzzy linguistic approach. An evaluation index system for ERCCIP is proposed. The weight of sub-criteria and criteria of the evaluation index system for ERCCIP are determined using the improved FPP. And the ratings of sub-criteria are assessed in linguistic values according to the experts＇ subjective opinions. Finally, the aggregated ratings of criteria and the overall ERCCIP are calculated.     

Preparation and performance of large-area La0.9Sr0.1Ga0.8Mg0.2O3−δ electrolyte for intermediate temperature solid oxide fuel cell

Pre-treated LSGM starting powders decrease in particle size, leading to an increase in the LSGM relative density and electric conductivity. The starting powders are ball-milled with the assistance of absolute ethanol to reduce the particle size, dried ultrasonically to prevent the agglomeration of the powders and pre-calcined and re-balled to increase the rate of grain growth. These improvements make it possible to obtain single phase LSGM powders with small particle size at the calcination temperature of 1300 °C. A large-area (9 cm × 9 cm) LSGM electrolyte substrate has been prepared successfully by tape casting from these powders. The LSGM electrolyte exhibits a dense structure, the relative density reaches 96%, and the electrical conductivity is 0.08 S cm⁻¹ at 800 °C.     

Rehabilitation of Masonry Walls Using Unobtrusive FRP Techniques for Enhanced Out-of-Plane Seismic Resistance

Earthquake damage to unreinforced masonry buildings has shown the vulnerability of perimeter walls to out-of-plane failure. This paper describes a study that was carried out to develop and test innovative fiber reinforced polymer (FRP) rehabilitation techniques that meet the stringent requirements for strengthening historical buildings and to be cost-effective alternatives applicable to other existing masonry structures. Unobtrusive FRP rehabilitation techniques that utilize flexible carbon fiber composite cables, mounted near the surface of the fa?ade walls in epoxy-filled grooves in the bed and head joints, were developed. Ten full size walls were constructed of clay bricks and retrofitted using the developed FRP rehabilitation techniques. The test results demonstrated the high efficiency of the rehabilitation techniques under both monotonic and quasistatic cyclic loadings. Significant increases in ultimate capacities, energy absorption, and deformability were achieved for various reinforcing schemes compared to the behavior of the unreinforced walls.     

Chemical compatibility, thermal expansion matches and electrochemical performance of SrCo0.8Fe0.2O3−δ-La0.45Ce0.55O2−δ composite cathodes for intermediate-temperature solid oxide fuel cells

The chemical compatibility, thermal expansion and electrochemical property measurements of the SrCo_0.8Fe_0.2O_3−δ (SCF)-La_0.45Ce_0.55O_2−δ (LDC) composite cathodes for solid oxide fuel cells (SOFCs) were investigated by X-ray diffraction (XRD), thermal expansion coefficients (TECs) and cathodic polarization measurements together with electrochemical impedance spectroscopy (EIS). The results indicated that LDC had good chemical compatibility with SCF and La_0.9Sr_0.1Ga_0.8Mg_0.2O_3−δ (LSGM), and the addition of LDC to SCF markedly reduced the polarization resistance. When the content of LDC reached 50 wt%, the SCF50 cathode showed the best electrochemical performance, with a cathodic overpotential of 0.1 V at the current density of 1102.0 mA cm⁻², together with a polarization resistance of 0.149 Ω cm² at 800 °C. The improved electrochemical performance was attributed to the expansion of the electrochemical reaction region into the electrode, and offering an easier path for the oxygen ion transport. Furthermore, the SCF-LDC composite cathodes match better with the LSGM electrolyte.