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Spectrum analysis of interval process model and its application in uncertain vibration analysis

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Science China(Technological Sciences) 2024年第8期67卷 2549-2564页

作者： LI JinWu jiang chao NI BingYu State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle College of Mechanical and Vehicle EngineeringHunan UniversityChangsha 410082China

In recent years, the authors have extended the traditional interval method into the time dimension to develop a new mathematical tool called the “interval process model” for quantifying time-varying or dynamic uncertainties. This model employs upper and lower bounds instead of precise probability distributions to quantify uncertainty in a parameter at any given time point. It is anticipated to complement the conventional stochastic process model in the coming years owing to its relatively low dependence on experimental samples and ease of understanding for engineers. Building on our previous work, this paper proposes a spectrum analysis method to describe the frequency domain characteristics of an interval process, further strengthening the theoretical foundation of the interval process model and enhancing its applicability for complex engineering problems. In this approach, we first define the zero midpoint function interval process and its auto/cross-power spectral density(PSD) functions. We also deduce the relationship between the auto-PSD function and the auto-covariance function of the stationary zero midpoint function interval process. Next, the auto/cross-PSD function matrices of a general interval process are defined, followed by the introduction of the concepts of PSD function matrix and cross-PSD function matrix for interval process vectors. The spectrum analysis method is then applied to random vibration problems, leading to the creation of a spectrum-analysis-based interval vibration analysis method that determines the PSD function for the system displacement response under stationary interval process excitations. Finally, the effectiveness of the formulated spectrum-analysis-based interval vibration analysis approach is verified through two numerical examples.

关键词： interval process spectrum analysis power spectral density(PSD) time-varying uncertainty uncertain vibration analysis

Characteristics of Bi-2223 HTS Tapes Under Short-Circuit Current Impacts in Hybrid Energy Transmission Pipelines

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 736-745页

作者： Yuguang Sun chao Yin Weizhen Li Xinyang Li Xiaohua jiang Department of Electric Engineering Tsinghua UniversityBeijing 100084China

A hybrid energy transmission pipeline is proposed with the aim of long-distance cooperative transmission of electricity and chemical fuels, which is composed of an inner high-temperature superconducting (HTS) power cable and outer liquefied natural gas (LNG) pipeline. The flowing LNG could maintain the operating temperature of the inner HTS power cable within the range of 85 K-90 K, thus the Bi-2223 superconductors in the HTS power cable produce little Joule loss with the transmission current below the critical current. Owing to the advantages of high power density, low transmission losses and economical manufacturing costs, the hybrid energy transmission pipeline is expected to be widely utilized in the near future. In order to ensure the safety of the HTS power cable and explosive LNG in case of short-circuit faults, this paper tests and analyzes the characteristics of Bi-2223 HTS tapes of the Type HT-CA, Type HT-SS and Type H models under short-circuit current impacts at the LNG cooling temperature (85 K-90 K). An experimental platform is designed and established for the ampacity tests of HTS tapes above LN2 cooling temperature (77 K). The AC over-current impact tests at 85 K-90 K are carried out on each sample of Bi-2223 tapes respectively, and the experimental results are analyzed and compared to evaluate their performances under different operating conditions. The results indicate that the Type HT-CA tape can withstand 50 Hz short-circuit current impact with the amplitude of 1108 A (10 times of critical current Ic ) for 100 ms at 90 K, and its resistance is the smallest of the three tested samples under similar current impacts. Therefore, the Type HT-CA Bi-2223 tape is the optimal superconductor of the HTS power cable in the hybrid energy transmission pipeline.

关键词： Bi-2223 high-temperature superconducting(HTS)tape critical current hybrid energy transmission pipeline liquefied natural gas(LNG)cooling temperature short-circuit current impact characteristics

Transferable adversarial slow feature extraction network for few-shot quality prediction in coal-to-ethylene glycol process

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Chinese Journal of Chemical Engineering 2024年第7期71卷 258-271页

作者： Cheng Yang chao jiang Guo Yu Jun Li Cuimei Bo School of Electrical Engineering and Control Science Nanjing Tech UniversityNanjing 211816China Department of Intelligent Manufacturing Nanjing Tech UniversityNanjing 210009China

In the coal-to-ethylene glycol(CTEG)process,precisely estimating quality variables is crucial for process monitoring,optimization,and control.A significant challenge in this regard is relying on offline laboratory analysis to obtain these variables,which often incurs substantial monetary costs and significant time *** resulting few-shot learning scenarios present a hurdle to the efficient development of predictive *** address this issue,our study introduces the transferable adversarial slow feature extraction network(TASF-Net),an innovative approach designed specifically for few-shot quality prediction in the CTEG ***-Net uniquely integrates the slowness principle with a deep Bayesian framework,effectively capturing the nonlinear and inertial characteristics of the CTEG ***,the model employs a variable attention mechanism to identify quality-related input variables adaptively at each time step.A key strength of TASF-Net lies in its ability to navigate the complex measurement noise,outliers,and system interference typical in CTEG *** learning strategy using a min-max game is adopted to improve its robustness and ability to model irregular industrial data accurately and ***,an incremental refining transfer learning framework is designed to further improve few-shot prediction performance achieved by transferring knowledge from the pretrained model on the source domain to the target *** effectiveness and superiority of TASF-Net have been empirically validated using a real-world CTEG *** with some state-of-the-art methods,TASF-Net demonstrates exceptional capability in addressing the intricate challenges for few-shot quality prediction in the CTEG process.

关键词： Chemical process Neural networks Slowness principle Transfer learning Prediction

A Path Planning Algorithm Based on Improved RRT Sampling Region

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Computers, Materials & Continua 2024年第9期80卷 4303-4323页

作者： Xiangkui jiang Zihao Wang chao Dong College of Automation Xi’an University of Posts and TelecommunicationsXi’an710121China

For the problem of slow search and tortuous paths in the Rapidly Exploring Random Tree(RRT)algorithm,a feedback-biased sampling RRT,called FS-RRT,is proposedbasedon ***,toimprove the samplingefficiency of RRT to shorten the search time,the search area of the randomtree is restricted to improve the sampling ***,to obtain better information about obstacles to shorten the path length,a feedback-biased sampling strategy is used instead of the traditional random sampling,the collision of the expanding node with an obstacle generates feedback information so that the next expanding node avoids expanding within a specific angle ***,this paper proposes using the inverse optimization strategy to remove redundancy points from the initial path,making the path shorter and more ***,to satisfy the smooth operation of the robot in practice,auxiliary points are used to optimize the cubic Bezier curve to avoid path-crossing obstacles when using the Bezier curve *** experimental results demonstrate that,compared to the traditional RRT algorithm,the proposed FS-RRT algorithm performs favorably against mainstream algorithms regarding running time,number of search iterations,and path ***,the improved algorithm also performs well in a narrow obstacle environment,and its effectiveness is further confirmed by experimental verification.

关键词： RRT inversive optimization path planning feedback bias sampling mobile robots

A promising application of bulk metallic glasses in torque sensor

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Science China(Technological Sciences) 2024年第8期67卷 2505-2514页

作者： LU WenHao MA jiang WANG chao LIU YanHui Institute of Physics Chinese Academy of SciencesBeijing 100190China Shenzhen Key Laboratory of High Performance Nontraditional Manufacturing College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China

Torque sensors are essential components of robotic joints. In the past, structure optimization of force-sensing elements has been the common approach to improve the performance of the torque sensors. In this work, we demonstrate a torque sensor with bulk metallic glasses as a force-sensing element. Compared with the sensors made of stainless steel and aluminum alloy, the use of bulk metallic glass as a force-sensing element significantly improves sensor sensitivity, linearity, repeatability, hysteresis, and measuring range. Our work not only opens up a new avenue for the application of bulk metallic glasses, but also provides opportunities for enhancing the performance of force/torque sensors through materials optimization.

关键词： bulk metallic glasses amorphous alloys force sensors

Fatigue Crack Propagation Law of Corroded Steel Box Girders in Long Span Bridges

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 201-227页

作者： Ying Wang Longxiao chao Jun Chen Songbai jiang Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education School of Civil EngineeringSoutheast UniversityNanjing211189China jiangsu Provincial Engineering Construction Standard Station Nanjing210036China

In order to investigate the fatigue performance of orthotropic anisotropic steel bridge decks,this study realizes the simulation of the welding process through elastic-plastic finite element theory,thermal-structural sequential coupling,and the birth-death element *** simulated welding residual stresses are introduced into the multiscale finite element model of the bridge as the initial ***,the study explores the impact of residual stress on crack propagation in the fatigue-vulnerable components of the corroded steel box *** results indicate that fatigue cracks at the weld toe of the top deck,the weld root of the top deck,and the opening of the transverse diaphragm will not propagate under the action of a standard vehicle ***,the inclusion of residual stress leads to the propagation of these *** considering residual stress,the fatigue crack propagation paths at the weld toe of the transverse diaphragm and the U-rib weld toe align with those observed in actual *** the absence of residual stress,the cracks at the toe of the transverse diaphragm with a 15%mass loss rate are categorized as type I ***,when residual stress is considered,these cracks become I-II composite *** stress significantly alters the cumulative energy release rate of the three ***,incorporating the influence of residual stress is essential when assessing the fatigue performance of corroded steel box girders in long-span bridges.

关键词： Residual stress crack propagation corroded steel box girder cumulative energy release rate

Robust Information Hiding Based on Neural Style Transfer with Artificial Intelligence

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Computers, Materials & Continua 2024年第5期79卷 1925-1938页

作者： Xiong Zhang Minqing Zhang Xu AnWang Wen jiang chao jiang Pan Yang College of Cryptography Engineering Engineering University of People’s Armed PoliceXi’an710086China Key Laboratory of People’s Armed Police for Cryptology and Information Security Xi’an710086China Key Laboratory of CTC&Information Engineering(Engineering University of People’s Armed Police) Ministry of EducationXi’an710086China Staff Department of People’s Armed Police Ningxia Corps Yinchuan750000China

This paper proposes an artificial intelligence-based robust information hiding algorithm to address the issue of confidential information being susceptible to noise attacks during *** algorithm we designed aims to mitigate the impact of various noise attacks on the integrity of secret information during *** method we propose involves encoding secret images into stylized encrypted images and applies adversarial transfer to both the style and content features of the original and embedded *** process effectively enhances the concealment and imperceptibility of confidential information,thereby improving the security of such information during transmission and reducing security ***,we have designed a specialized attack layer to simulate real-world attacks and common noise scenarios encountered in practical *** adversarial training,the algorithm is strengthened to enhance its resilience against attacks and overall robustness,ensuring better protection against potential *** results demonstrate that our proposed algorithm successfully enhances the concealment and unknowability of secret information while maintaining embedding ***,it ensures the quality and fidelity of the stego *** method we propose not only improves the security and robustness of information hiding technology but also holds practical application value in protecting sensitive data and ensuring the invisibility of confidential information.

关键词： Information hiding neural style transfer robustness

A hybrid WUDT-NAFnet for simultaneous source data deblending

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Petroleum Science 2024年第3期21卷 1649-1659页

作者： chao-Fan Ke Shao-Huan Zu Jun-Xing Cao Xu-Dong jiang chao Li Xing-Ye Liu Key Laboratory of Earth Exploration and Information Technology of Ministry of Education Chengdu University of Technology State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology College of Geophysics Chengdu University of Technology

Simultaneous source technology,which reduces seismic survey time and improves the quality of seismic data by firing more than one source with a narrow time interval,is compromised by the massive blended ***,deblending algorithms have been developed to separate this ***,deep learning(DL)has been proved its great potential in suppressing the *** most popular DL method employs neural network as a filter to attenuate the blended noise in an iterative estimation and subtraction framework(IESF).However,there are still amplitude distortion and blended noise residual problems,especially when dealing with weak signal submerged in strong *** address these problems,we propose a hybrid WUDT-NAFnet,which contains two *** first network is a wavelet based U-shape deblending transformer network(WUDTnet),incorporated into IESF as a robust regularization term to iteratively separate the blended *** second network is a nonlinear activate free network(NAFnet)designed to recover the event amplitude and further suppress the weak noise residual in *** the hybrid network,the blended noise can be separated purposefully and *** using synthetic and field seismic data demonstrate that the WUDTNAFnet outperforms traditional curvelet transform(CT)based method and the deblending transformer(DT)model in terms of ***,for field applications,the data augmentation method of bicubic interpolation is applied to mitigate the feature difference between synthetic and field ***,the trained network exhibits strong signal preservation ability in numerical field example without requiring additional training.

关键词： Simultaneous-source Deblending Deep learning Transformer

Experimental Study on the Molten Salt at Micron Scale during the Melting Process

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Journal of Thermal Science 2024年第1期33卷 70-85页

作者： TIAN Ziqian LIAO Zhirong XU chao FANG Yongzhe jiang Kaijun YUAN Mengdi Key Laboratory of Power Station Energy Transfer Conversion and System Ministry of Education of ChinaSchool of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing 102206China

The investigation of the melting behaviors of the molten salt at micron scale during the melting process is critical for explaining the solid-liquid phase transition *** this paper,a novel experimental system and analysis method were proposed to study the melting process with three heating rates in the range of1-10℃/min of the solar salt at micron *** solid-liquid boundary morphology and phase transition kinetics of molten salt particles were focused ***,the correlations between liquid fraction,temperature and time under different heating rates were *** solid-liquid boundary morphology was depicted by the visualized experimental set-up,and the instantaneous liquid volume fraction during the non-isothermal phase transition was ***,the correlation between temperature and liquid volume fraction was proposed to reveal the evolution of the solid-liquid boundary with temperature at different heating ***,the non-isothermal phase transition kinetic equation was established by introducing a constant parameter(V_(a,b)),and more kinetic parameters such as 1g V_(a,b) and-lg V_(a,b)/b were *** results showed that the exponent b is not sensitive to the heating rate with a range of 3-5 for solar salt ***,the heating rate influences the value of V_(a,b) and presents a positive ***,the non-isothermal phase transition kinetic equations at different heating rates in the range of 1-10℃/min can be quickly predicted by the proposed improved experimental test *** study could fill the research insufficiency and provide significant guidance for future research on the solid-liquid transition mechanism of molten salts at micron scale.

关键词： molten salt non-isothermal phase transition solid-liquid boundary morphology liquid volume fraction micron scale melting process