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Science China(Information Sciences) 2025年

作者： Yunxiang MA tong ZHOU Department of Automation Tsinghua University Department of Automation and BNRist Tsinghua University

This paper investigates the identifiability of structured systems with a matrix fraction description and attacks practical difficulties in estimating parameters under finite frequency responses. The numerator and denominator polynomial matrices depend affinely on system parameters, which can represent a broad range of systems, especially circuits and mechanical systems. Except for assuming that the denominator matrix is invertible, no further assumptions are adopted. A criterion is provided for validating this assumption utilizing graph theories and matroids. A sufficient and necessary criterion for global identifiability based on the rank of a numerical matrix is given and can be recursively verified with each frequency point,which is computationally attractive for large-scale systems. For an identifiable system, an ellipsoid approximation is obtained for the set of parameters whose corresponding system frequency responses deviate within a specific range from those of the system at a specific parameter value. Using this approximation, explicit expressions for absolute and relative sloppiness have been derived, which can be used to quantify the difficulty of identifying system parameters. Comparisons with the well-known Fisher information matrix have also been performed through a mechanical system, revealing significant differences in quantifying parameter estimation hardness.

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Pronounced impact of size and shape effects on creep rupture life of a K439B superalloy combustion chamber casting simulator

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China Foundry 2025年

作者： Wen-tong liu Yi-dong Wu Lei Gao Jing-yang Chen Cheng-bo Xiao Xi-dong Hui State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Science and Technology on Advanced High Temperature Structural Materials Laboratory Beijing Institute of Aeronautical Materials

The size and shape effect(SSE) of components has become a critical issue for mechanical properties, application reliability, and processing. In this study, the creep rupture life(CRL) of components with different wall thicknesses and positions in a combustion chamber casing simulator made of K439B superalloy was investigated. The intrinsic mechanisms of the SSE were explored from the dendrite structure, volume fraction and size of the γ' phase, and element segregation, etc. It is shown that this casting exhibits a strong SSE of creep rupture life, characterized by a significant difference in the CRL values up to 60% with the variation of wall thickness and position in the casing. In terms of casting technology, the influence of SSE on CRL is actually determined by the cooling rate. The SSE on the creep rupture life originates from the dendrite structure(such as the secondary dendrite arm spacing), volume fraction size of the γ' phase in the dendrite trunk, and elements segregation rate. This work may have implications for the design and application of engineering components with large sizes and complex structures.

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附加尺度参数的地籍宗地面积处理

同济大学学报（自然科学版） 2002年第4期30卷 490-494页

作者：刘大杰童小华赵建国同济大学测量与国土信息工程系上海200092

提出了在平差模型中附加面积尺度参数 ,并采用带参数的条件平差方差分量估计来确定不同观测值的权 ,以进行宗地面积处理 .为了检验面积的尺度性系统误差的显著性 ,利用平差计算的结果进行了显著性假设检验 .并采用四种面积处理方案对实... 详细信息

提出了在平差模型中附加面积尺度参数 ,并采用带参数的条件平差方差分量估计来确定不同观测值的权 ,以进行宗地面积处理 .为了检验面积的尺度性系统误差的显著性 ,利用平差计算的结果进行了显著性假设检验 .并采用四种面积处理方案对实例进行计算和比较 .理论分析和实际计算表明 ,附加尺度参数 ,可以更好地减弱或探测宗地数字化中的面积尺度性系统误差的影响 .同时 ,在面积系统性误差较大的情况下 ,附加面积尺度参数来处理是必要的 ,其效果也是明显的 .

关键词：尺度参数地籍宗地面积处理方差分量估计平差精度分析

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C80型煤矿专用敞车装车牵引装置研制

煤矿机械 2016年第3期37卷 108-109页

作者：辛润堂刘大同同煤集团山西大同037003

针对目前存在的老矿井无法装载C80型煤矿专用敞车的问题,介绍了一种专项研制装置,能够较好解决问题。阐述了C80型煤矿专用敞车装车牵引装置的组成、结构和现场应用情况及效果,进行了牵引装置受力分析和强度安全性验算,提出牵引装置配套... 详细信息

针对目前存在的老矿井无法装载C80型煤矿专用敞车的问题,介绍了一种专项研制装置,能够较好解决问题。阐述了C80型煤矿专用敞车装车牵引装置的组成、结构和现场应用情况及效果,进行了牵引装置受力分析和强度安全性验算,提出牵引装置配套绞车牵引方式,结构简单,操控方便,投资少、易推广。

关键词： C80型敞车装车牵引装置研制

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股骨转子间骨折外侧壁损伤的治疗进展

中国矫形外科杂志 2018年第6期26卷 524-527页

作者：刘康佟大可章浩王光超秦升纪方长海医院创伤骨科上海200433

股骨转子间骨折是常见的骨质疏松性骨折之一。保守治疗需要卧床制动,老年人长期卧床容易造成褥疮、泌尿系感染、肺部感染、深静脉血栓形成等全身并发症,治疗难度大,患者死亡率高,目前主张积极手术治疗。其中,伴有外侧壁损伤的转子间骨折... 详细信息

股骨转子间骨折是常见的骨质疏松性骨折之一。保守治疗需要卧床制动,老年人长期卧床容易造成褥疮、泌尿系感染、肺部感染、深静脉血栓形成等全身并发症,治疗难度大,患者死亡率高,目前主张积极手术治疗。其中,伴有外侧壁损伤的转子间骨折,作为不稳定性的转子间骨折,在治疗过程中常常由于认识不足,治疗不当导致术后内固定失败,再次给患者带来痛苦,于是外侧壁损伤的研究成为热点。本文就外侧壁的概念、损伤分型、治疗方式的选择、外侧壁损伤的预防和处理进行综述,进一步提高对于伴有外侧壁损伤的转子间骨折的认识,为今后临床治疗提供参考。

关键词：股骨转子间骨折外侧壁损伤进展

Marine dispersion of Fukushima-derived radiocesium in the North Pacific and its implications

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Science China Earth Sciences 2025年

作者： tong ZHANG Xiaolin HOU Yukun FAN State Key Laboratory of Loess and Quaternary Geology Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application Xi'an AMS Center Institute of Earth Environment Chinese Academy of Sciences University of Chinese Academy of Sciences Xi'an Institute for Innovative Earth Environment Research

A key scientific approach to addressing the environmental radiation risks from Fukushima nuclear contaminated water （FNCW） discharge into the ocean is understanding and predicting the marine dispersion of *** dispersion of radiocesium (CsF:134Cs,137Cs) from the Fukushima nuclear accident in the North Pacific and its marginal seas post-2011 was systematically summarized,focusing on pathways,vertical distribution changes,and transit *** research examined CsFdispersion through the Kuroshio Extension and denser central mode water （D-CMW） to the eastern North Pacific,as well as through subtropical mode water （STMW）,lighter central mode water （L-CMW）,and D-CMW to the subtropical western North Pacific,China Seas,and Sea of *** considered broader implications of CsFdispersion in light of ongoing FNCW *** this prolonged liquid discharge and Kuroshio Extension’s barrier effect,it is crucial to emphasize the role of CMW besides STMW in transporting FNCW to the subtropical western North Pacific and its marginal *** research should focus on the key mechanism and longitude range of CMW crossing the Kuroshio *** short-lived134Cs decays rapidly during the storage and dispersion of FNCW,long-lived135Cs and135Cs/137Cs ratios can serve as valuable tracers for detecting and quantifying ***,there is an urgent need for high-precision analysis of these key radionuclides and their characteristic *** promptly detect,assess,and respond to FNCW intrusion,continuous monitoring and identification of nuclear pollution sources in key ocean currents and straits are ***,interdisciplinary research integrating monitoring with marginal sea circulation dynamics and high-resolution numerical simulations should be a priority

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Weak feedback self-mixing interference fringe slope discrimination method based on deep learning

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Optoelectronics Letters 2025年

作者： ZHAO Yan LIN Maohua DU Shengzhi tong Jigang liu Bin HAN Fangfang School of Electrical Engineering and Automation， Tianjin University of Technology Tianjin Key Laboratory for Control Theory and Applications in Complicated Systems Department of Electrical Engineering， Tshwane University of Technology

In order to identify the tilt direction of the self-mixing interference (SMI) signals under weak feedback regime interfered by noise， a deep learning method is proposed. The one-dimensional U-Net (1D U-Net) neural network can discriminate the direction of self-mixing fringes accurately and quickly. For experimental SMI signals， the 1D U-Net can be used for discriminant direction after a one-step normalization. Simulation and experimental results show that the proposed method is suitable for SMI signals with noise within the whole weak feedback regime， and can maintain a high discrimination accuracy for signals interfered by 5dB noise. Combined with fringe counting method， accurate and rapid SMI signal displacement reconstruction can be realized.

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A reduction scheme of PAPR in CO-OFDM system using time-delay neural networks

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Optoelectronics Letters 2025年

作者： tong Zhengrong liu Zhihong WANG Hao ZHANG Weihua ZHANG Tianhao JIA Qiqi Tianjin Key Laboratory of Thin Film Electronics and Communication Devices， Engineering Research Center for Optoelectronic Devices and Communication Technology of the Ministry of Education， School of Integrated Circuit Science and Engineering， Tianjin University of Technology

An iterative partial transmission sequence （IPTS） cascading time-delay neural network （TDNN） scheme is proposed to reduce peak-to-average power ratio （PAPR） in the coherent optical orthogonal frequency division multiplexing （CO-OFDM） systems. The IPTS algorithm further reduces computational complexity based on the partial transmission sequence （PTS） algorithm. TDNN is trained by the iterative clipping filtering （ICF） method. Simulation results show that the proposed scheme achieves a PAPR reduction of 5.84 dB when complementary cumulative distribution function （CCDF） is 10-4and an extra transmission distance of 200 km for 10-3bit error rate （BER） compared to the original signals.

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料仓结构设计中的贮料压力计算分析

河北工程技术高等专科学校学报 2010年第1期 13-15页

作者：刘大同张宝魁李斌长江勘测规划设计研究院河北武汉430010 河北工业大学土木工程学院天津300132

料仓贮料压力计算是料仓结构设计中的重要一环,其计算方式分为深仓和浅仓两种。本文通过具体算例分析,对钢筋混凝土料仓和钢料仓在贮料压力计算中应注意的压力复核问题进行了总结,提出了较实用的解决办法。

关键词：料仓贮料压力深仓浅仓压力复核

Study on the hydrogen absorption properties of a YGdTbDyHo rare-earth high-entropy alloy

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 127-135页

作者： tongyue Li Ziliang Xie Wenjiao Zhou Huan tong dawen Yang Anjia Zhang Yuan Wu Xiping Song State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Whole Win(Beijing)Materials Sci.&Tech.Co. Ltd.Beijing 100083China

This study investigated the microstructure and hydrogen absorption properties of a rare-earth high-entropy alloy(HEA),*** indicated that the YGdTbDyHo alloy had a microstructure of equiaxed grains,with the alloy elements distributed *** hydrogen absorption,the phase structure of the HEA changed from a solid solution with an hexagonal-close-packed(HCP)structure to a high-entropy hydride with an faced-centered-cubic(FCC)structure without any secondary phase *** alloy demonstrated a maximum hydrogen storage capacity of 2.33 H/M(hydrogen atom/metal atom)at 723 K,with an enthalpy change(ΔH)of-141.09 kJ·mol^(-1)and an entropy change(ΔS)of-119.14 J·mol^(-1)·K^(-1).The kinetic mechanism of hydrogen absorption was hydride nucleation and growth,with an apparent activation energy(E_(a))of 20.90 kJ·mol^(-1).Without any activation,the YGdTbDyHo alloy could absorb hydrogen quickly(180 s at 923 K)with nearly no incubation period *** reason for the obtained value of 2.33 H/M was that the hydrogen atoms occupied both tetrahedral and octahedral *** results demonstrate the potential application of HEAs as a high-capacity hydrogen storage material with a large H/M ratio,which can be used in the deuterium storage field.

关键词： rare-earth high-entropy alloy hydrogen absorption capacity pressure–composition–temperature curves kinetics