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??This paper constructs a penalized empirical likelihood estimation method via quadratic inference function method, filter method and empirical likelihood estimation method. Under some regular conditions, we derived the large sample properties of estimators and show that the proposed empirical likelihood ratio is asymptotically to chi-square distribution. Furthermore, the infinite sample performance of the proposed method is evaluated by Monte Carlo simulation and real data analysis.     

四边简支含多孔材料双层板隔声特性

有限大含多孔材料和空气层复合板结构隔声特性的研究尚不充分。该文旨在研究四边简支边界条件下复合板结构隔声特性。首先基于流体饱和多孔弹性介质的声传播理论计算了声波在多孔介质中的传播波数；继而采用四边简支边界条件下板结构的模态函数，利用模态叠加法和伽辽金法推导了复合板结构隔声系数理论模型，并数值求解复合板隔声量。将理论模型得到的四边简支复合板隔声量与实验结果对比，验证了理论模型的正确性。最后，详细讨论了边界条件、板结构尺寸和多孔材料厚度等主要参数对隔声特性的影响。结果表明：四边简支复合结构隔声特性曲线上“谷值”出现得较少，并且简支复合板隔声特性的第一个“吻合频率”比固支支撑复合板更靠近低频，当频率超过3000 Hz以后，简支和固支边界条件复合板结构隔声特性趋于一致。     

存在随机解释变量的平行数据模型的处理

本文研究了平行数据模型中存在随机解释变量的解决方法:构造了模型设定的假设检验,给出了参数的一致估计量,并通过建立山东省城镇家庭烟草消费额模型进行了实证分析.     

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??In this paper, we focus on the tests for covariance matrices in panel data model with interactive fixed effects. For the problem of testing identity and sphericity of covariance matrices, we first propose test statistics based on the estimators of the trace of covariance matrices. Under both the null hypothesis and the alternatives, we establish the asymptotic distributions of the proposed test statistics under some regularity conditions, and we further show that the proposed tests are distribution free. Subsequently simulation studies suggest that the proposed tests perform well under the high dimensional panel data.     

Testing for Covariance Matrices in Panel Data Models with Interactive Fixed Effect

In this paper, we focus on the tests for covariance matrices in panel data model with interactive fixed effects. For the problem of testing identity and sphericity of covariance matrices, we first propose test statistics based on the estimators of the trace of covariance matrices. Under both the null hypothesis and the alternatives, we establish the asymptotic distributions of the proposed test statistics under some regularity conditions, and we further show that the proposed tests are distribution free. Subsequently simulation studies suggest that the proposed tests perform well under the high dimensional panel data.     

太阳能帆板平面度测量系统中光斑图像处理方法研究

太阳能帆板的平面度测量是卫星生产制造过程中的一个关键技术，现有的测量方法存在着精度差，效率低的问题。该文在基于实际工程课题的太阳能帆板平面度测量系统基础上，针对测量系统中光斑图像处理这一关键技术进行了详细的研究。对现有测量方法进行了比较与分析，介绍了测量系统的基本原理、图像采集系统设计过程中采取的主要措施、图像处理的具体方法与步骤和测量系统的基本组成。提出了一种新的快速滤波算法和光斑图像能量中心求取算法，大大提高了光斑图像能量中心的求取精度和实时性，提高了太阳能帆板平面度的测量精度。给出了光斑图像处理结果、静态测量重复性误差以及实际帆板的测量结果与分析，实验结果证明所采用的光斑图像处理方法可以满足对实际帆板测量精度的要求。     

The Panel Method for Rigid Section Group Added Mass Coefficients and Its Application to Fuel Assemblies北大核心CSCD

A numerical method based on the panel method was developed to calculate the added fluid mass coefficients of the rigid section group with arbitrarily complex shapes, and was successfully applied to the PWR fuel assemblies. The variation law of added mass coefficients with position deviations was analyzed in the seismic test of 1×5 fuel assemblies. The results show that, this method is suitable for the calculation of the added mass coefficients of rigid section groups with complex continuous boundaries. Compared with the gap between assemblies, the gap between baffles and assemblies has a dominant influence on the added mass coefficient. Regardless of the position deviation, the sum of the added mass coefficients of all assemblies and baffles in the assumed motion direction is approximately equal to –1, and that in the perpendicular direction is approximately equal to 0. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

Enhancing micro-perforated panel attenuation by partitioning the adjoining cavity

The sound attenuation performance of micro-perforated panels (MPP) with adjoining air cavity is investigated for a plenum. The sound field inside of a plenum is compared for two cases. In the first case, the plenum is treated with an MPP and adjoining air cavity without any partitioning. For the second case, the adjoining air cavity is partitioned into a number of sub-cavities. The resulting sound pressure fields indicate that partitioning the adjoining air cavity increases the overall sound attenuation due to the MPP by approximately 4 dB. The explanation for this phenomenon was investigated by measuring the sound pressure level on planes in front of the MPP. Additionally, boundary element analyses were conducted to simulate the effect of the MPP and adjoining cavity with and without partitioning on the sound field in the plenum. It was demonstrated that a MPP can be modeled as a transfer impedance and that partitioning the adjoining cavity enhances attenuation to acoustic modes that propagate transverse to the MPP.     

中国农村居民消费结构的Panel Data模型分析

基于持久收入假设消费理论,建立中国农村居民消费的Panel Data模型,分析中国农村居民不同收入层次之间的消费差异,以及这种差异对农村居民消费结构的影响.结果表明:不同收入层次的农村居民的总消费支出差异显著,衣着消费模型为变截距模型,而居民食品、居住等其他消费支出差异不显著,模型表现形式一致,因此启动农村居民消费需求归根到底是要提高低收入层次居民的收入,拉动高收入层次居民的消费需求。     

我国农民消费问题的分省面板协整模型分析

依据现代消费理论,在符合中国经济现实假设条件下,建立了我国农民消费问题的数理函数。使用1980-2006年的宏观消费数据,通过协整模型分析表明我国农民的边际消费倾向约为0.69;基于Hausman检验的固定效应模型的面板单位根和面板协整对我国30个省份分析结果表明边际消费倾向为0.7;变截距变斜率面板模型表明各省的长期自主消费和长期边际消费倾向差异显著,上海、江苏呈现双高特征,吉林、海南和西藏则呈现双低特征,其他省份则表现为自主消费和边际消费倾向两者此高彼低的特点。差异产生的原因在于消费习惯不同以及收入差异导致的"主动、被动"消费造成的结果,提出了为西部增收以促进消费良性循环的合理的政策建议。