一种新的多渐消因子容积卡尔曼滤波

将强跟踪思想引入容积卡尔曼滤波（cubature Kalman filter，CKF），建立强跟踪CKF能有效克服CKF在模型不确定、状态突变等情况下，滤波性能下降的问题。通过分析现有多渐消因子计算方法，发现它们均只利用了协方差矩阵的对角线元素，并没有考虑各个状态之间的相关性，不能充分发挥多渐消因子的优势。为此，本文提出渐消因子矩阵，基于正交原理推导渐消因子矩阵的求解方法，提出多渐消因子强跟踪CKF算法。多渐消因子强跟踪CKF算法突破了传统多渐消因子为向量的限制，也不再要求渐消因子取值要大于1。仿真验证了算法具有更好的滤波精度何鲁棒性，能更好的满足工程应用的要求。     

低温固化聚氨酯防水涂料

合成了一系列芳香族多元胺类化合物，介绍了用以制备低温固化的聚氨脂防水涂料的配备方法和性能，讨论了若干影响因素。     

北京地区非饱和土土压力初步研究

根据朗肯土压力理论,北京地区土压力计算值远大于实测土压力值。针对这个急需解决的问题进行了探讨,引入广义朗肯土压力公式,结合北京地铁13号线东直门车站基坑支护工程,对理论计算土压力和实测土压力进行了详细的分析,给出了该地区非饱和土土压力计算的基于试验指标的广义朗肯土压力表达式。     

N型方圆钢管相贯节点足尺试验研究

对两个承受支管轴力和主管轴力的搭接N型方圆钢管相贯节点进行了足尺试验研究。试验表明,试件N1的破坏模式为受压支管在节点处的局部屈曲破坏,试件N2的破坏模式为主管侧壁鼓曲破坏和支主管交接面主管壁压溃破坏的联合破坏模式。计算表明,试件N1的试验值与《钢结构设计规范》(GB 50017—2003)公式承载力计算结果的比值为0.73,与有限元计算结果的比值为1.11;试件N2的试验值与规范公式承载力计算结果的比值为0.99,与有限元计算结果的比值为1.02。研究表明,主管轴力对节点极限承载力影响较大,规范公式因未考虑主管轴力的影响,其计算结果偏不安全,还有待进一步的研究。     

强跟踪自适应CKF及其在动力定位中应用

针对容积卡尔曼滤波(cubature Kalman filter,CKF)在动力定位系统存在不良测量及船舶运动模型不确定时滤波精确度下降甚至发散的问题,提出一种强跟踪自适应CKF算法。利用新息协方差匹配原理,建立对系统的不良测量具有鲁棒性的自适应CKF。基于强跟踪滤波(strong tracking filter,STF)的理论框架和自适应CKF算法,构建强跟踪自适应CKF,该算法克服了标准强跟踪滤波的理论局限性,兼具STF与自适应CKF的优点,在系统存在模型不确定性及不良测量时具有良好的鲁棒性和滤波精确度。通过仿真验证了所建算法的有效性。     

Calderon's preconditioning for periodic fast multipole method for elastodynamics in 3D

Preconditioning methods based on Calderon's formulae for the periodic fast multipole method for elastodynamics in 3D are investigated. Three different types of formulations are proposed. The first type is a preconditioning just by appropriately ordering the coefficient matrix without multiplying preconditioners. The other two types utilise preconditioners constructed using matrices needed in the main fast multipole method algorithms. We make several numerical experiments with proposed preconditioners to confirm the efficiency of these proposed methods. We also conclude that the preconditioning of the first type is faster with respect to the computational time than other preconditioning methods discussed in this article. Copyright © 2012 John Wiley & Sons, Ltd.     

Multiclass method for fast determination of veterinary drug residues in baby food by ultra-high-performance liquid chromatography–tandem mass spectrometry

A simple and rapid multiresidue method for the determination of different veterinary drug residues in meat-based baby food (MBF) and powdered milk-based infant formulae (PMIF) has been developed. The method involves an extraction procedure based on buffered QuEChERS (quick, easy, cheap, effective, rugged and safe) methodology, without any further clean-up step, followed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The method has been validated in two baby food matrices (MBF and PMIF) at three different concentration levels, obtaining suitable recoveries and precision (inter and intra-day precision) values. Quantification was carried out using matrix-matched standard calibration. Furthermore, the decision limit (CCα) and the decision capability (CCβ) were evaluated, ranging from 0.5 to 16.2 μg/kg and from 1.2 to 22.4 μg/kg, respectively. Finally, the method was applied to the analysis of several kinds of baby food samples and traces of some veterinary drugs were detected.     

Composite embedded cubature Kalman filter

The embedded cubature Kalman filter (ECKF) is proven as a kind of algorithm that has higher precision than cubature Kalman filter. Based on the ECKF, a new algorithm, named composite ECKF (CECKF), is presented in this paper. The new CECKF can increase filter precision by means of reusing the embedded cubature rule in the process of numerical approximation, which can realize higher precision than ECKF in theory. At the same time, another new algorithm, named adaptive CECKF, is also put forward by introducing an adaptive method based on CECKF. Through the comparison of simulation, the proposed methods are able to enhance filter precision.     

Development of P-I diagrams for FRP strengthened RC columns

In this study, numerical simulations are performed to construct the Pressure-Impulse (P-I) diagrams for FRP strengthened RC columns to provide correlations between the damage levels of FRP strengthened RC columns and blast loadings. Numerical model of RC columns without or with FRP strengthening is developed using LS-DYNA. The accuracy of the model to simulate RC column responses to blast loads is verified by comparing the numerical simulation results with the tests results available in the literature. Dynamic response and damage of RC columns with different FRP strengthening measures are then calculated using the developed numerical model. The residual axial-load carrying capacity is utilized to quantify the damage level since the columns are primarily designed to carry the axial loads. Parametric studies are performed to examine the influence of column dimension, concrete strength, steel reinforcement ratios, FRP thickness and FRP strength on the P-I diagrams. The empirical formulae are derived based on numerical results to predict the impulse and pressure asymptote of P-I diagrams. These empirical formulae can be straightforwardly used to construct P-I diagrams for assessment of blast loading resistance capacities of RC columns with different FRP strengthening measures.     

Application of the parametric for mulae for electromagnetic showers in unconverted γ/π~0 discrimination

In the LHC experiment, the neutral pions produced during jet fragmentation are the background sources for all physics channels with high-energy photons in their final state. In this paper, the application of the three-dimensional parametric formula for el