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Acta Mechanica Sinica 2024年第7期40卷 1-18页

作者： Qingjiang Yuan Runjie Song Ming dong State Key laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This paper studies the local receptivity of the Mack-mode instability to localized unsteady blowing and suction(UBS)in a chem-ical non-equilibrium(CNE)hypersonic boundary *** five-species CNE model is employed,and the receptivity efficiency is formulated by use of the residual *** with the results for the calorically perfect gas(CPG)model,we find that the real-gas effect enhances the receptivity efficiency remarkably in the majority of the second-mode frequency band,and the enhancement is mainly attributed to the modification of the base flow due to the CNE effect,which is akin to the cold-wall effect in hypersonic boundary *** with the destabilizing role of the CNE effect on the Mack second mode,it is concluded that the CNE effect would lead to a greater linearly accumulated perturbation amplitude,implying premature of transition to turbulence in a high-enthalpy hypersonic boundary layer subject to localized perturbations.

关键词： Chemical non-equilibrium flow Boundary-layer instability Hypersonic Receptivity Transition to turbulence

Low-resolution Kramers-Kronig detection system with error-feedback noise shaping

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Science China(Information Sciences) 2024年第5期67卷 259-269页

作者： Xiangyong dong Zhenming YU Hongyu HUANG Kaixuan SUN Kun XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

In this paper, we investigated the effects of error-feedback noise shaping(EFNS) on a lowresolution Kramers-Kronig(KK) detection system for the first time. Both 16-ary quadrature amplitude modulation(16-QAM) and 64-ary quadrature amplitude modulation(64-QAM) were considered in the experiment. The carrier tone was added on the transmitter side using the virtual carrier-assisted single sideband(VCA-SSB) method to meet the minimum phase(MP) condition. Under the MP condition, KK detection only needs the intensity of the optical signal to be detected by one photodiode(PD) to retrieve the phase information. However, the virtual carrier tone increases the carrier-to-signal power ratio(CSPR), which results in a high peak-to-average power ratio(PAPR) at the transmitter, causing an increase in quantization noise. To mitigate quantization noise in the low-resolution KK detection system, EFNS was applied. The application of EFNS increased the optimal CSPR of the KK detection system and improved receiver sensitivity. Using a 4-bit DAC and the EFNS, 80 km transmission was achieved in the 60-Gbit/s 64-QAM KK detection system.

关键词： optical fiber communications Kramers-Kronig receiver error-feedback noise shaping quantization noise carrier-to-signal power ratio

Optimal Stochastic Scheduling Strategy of Multi-vector Energy Complex Integrated with Full-blown Power-to-biomethane Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 863-873页

作者： Guanwei Zeng Chengxi Liu Minfang Liao Yongjian Luo Xuzhu dong Hubei Engineering and Technology Research Center for AC/DC Intelligent Distribution Network WuhanChina the School of Electrical Engineering and Automation Wuhan UniversityWuhanChina

We propose an optimal stochastic scheduling strategy for a multi-vector energy complex(MEC),considering a fullblown model of the power-to-biomethane(Pt M)*** conventional optimization that uses a simple efficiency coefficient to coarsely model energy conversion between electricity and biomethane,a detailed Pt M model is introduced to emphasize the reactor kinetics and chemical equilibria of *** model crystallizes the interactions between the Pt M process and MEC flexibility,allowing to adjust the operating condition of the methanation reactor for optimal MEC operation in stochastic *** optimization and flowsheet design of the Pt M process increase the average selectivity of methane(i.e.,ratio between net biomethane production and hydrogen consumption)up to 83.7%in the proposed synthesis *** results can provide information and predictions to operators about the optimal operating conditions of a Pt M unit while improving the MEC flexibility.

关键词： Multi-vector energy complex optimal stochastic scheduling power-to-biomethane unit process synthesis natural gas

In situ infrared, Raman and X-ray spectroscopy for the mechanistic understanding of hydrogen evolution reaction

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Journal of Energy Chemistry 2024年第3期90卷 632-651,I0014页

作者： Andi Haryanto Kyounghoon Jung Chan Woo Lee dong-Wan Kim Department of Chemistry Kookmin UniversitySeoul 02707Republic of Korea School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

Hydrogen production by water reduction reactions has received considerable attention because hydrogen is considered a clean-energy carrier,key for a sustainable energy *** methods have been widely used to study the reaction mechanism of the hydrogen evolution reaction(HER),but the calculation results need to be supported by experimental results and direct evidence to confirm the mechanistic *** this review,we discuss the fundamental principles of the in situ spectroscopic strategy and a theoretical model for a mechanistic understanding of the *** addition,we investigate recent studies by in situ Fourier transform infrared(FTIR),Raman spectroscopy,and X-ray absorption spectroscopy(XAS) and cover new findings that occur at the catalyst-electrolyte interface during *** spectroscopic strategies provide practical ways to elucidate catalyst phase,reaction intermediate,catalyst-electrolyte interface,intermediate binding energy,metal valency state,and coordination environment during HER.

关键词： Hydrogen evolution reaction Infrared spectroscopy Raman spectroscopy X-ray absorption spectroscopy Reaction mechanism

A benchmark-based method for evaluating hyperparameter optimization techniques of neural networks for surface water quality prediction

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Frontiers of Environmental Science & Engineering 2024年第5期18卷 13-27页

作者： Xuan Wang Yan dong Jing Yang Zhipeng Liu Jinsuo Lu School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi’an710055China Shaanxi Key Laboratory of Environmental Engineering Xi’an University of Architecture and TechnologyXi’an710055China State Key Laboratory of Green Building in West China Xi’an University of Architecture and TechnologyXi’an710055China

Neural networks(NNs)have been used extensively in surface water prediction tasks due to computing algorithm improvements and data *** essential step in developing an NN is the hyperparameter *** practice,it is common to manually determine hyperparameters in the studies of NNs in water resources *** may result in considerable randomness and require significant computation time;therefore,hyperparameter optimization(HPO)is *** study adopted five representatives of the HPO techniques in the surface water quality prediction tasks,including the grid sampling(GS),random search(RS),genetic algorithm(GA),Bayesian optimization(BO)based on the Gaussian process(GP),and the tree Parzen estimator(TPE).For the evaluation of these techniques,this study proposed a method:first,the optimal hyperparameter value sets achieved by GS were regarded as the benchmark;then,the other HPO techniques were evaluated and compared with the benchmark in convergence,optimization orientation,and consistency of the optimized *** results indicated that the TPE-based BO algorithm was recommended because it yielded stable convergence,reasonable optimization orientation,and the highest consistency rates with the benchmark *** optimization consistency rates via TPE for the hyperparameters hidden layers,hidden dimension,learning rate,and batch size were 86.7%,73.3%,73.3%,and 80.0%,*** the evaluation of HPO techniques directly based on the prediction performance of the optimized NN in a single HPO test,the proposed benchmark-based HPO evaluation approach is feasible and robust.

关键词： Neural networks Hyperparameter optimization Surface water quality prediction Bayes optimization Genetic algorithm

Tetrabromobisphenol A exerts thyroid disrupting effects but has little overt impact on postnatal brain development and neurobehaviors in mice

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Journal of Environmental Sciences 2024年第8期142卷 1-10页

作者： Shilin Song Yuanyuan Li Lin Lv Mengqi dong Zhanfen Qin State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China School of Environment Tsinghua UniversityBeijing 100084China

Tetrabromobisphenol A(TBBPA)is a widely used brominated flame *** is evidence showing that TBBPA can exert thyroid disrupting effects in mammals,but different results were also reported,along with inconsistent reports regarding its ***,we investigated thyroid disrupting effects and neurotoxicity of TBBPA(5,50,500μg/(kg·day))to male mice following maternal and direct exposure through drinking water,with the antithyroid drug propylthiouracil(PTU)as the positive *** postnatal day(PND)15,we expectedly observed severe thyroid compensatory hyperplasia and cerebellar developmental retardation in PTU-treated *** highest dose of TBBPA also caused thyroid histological alteration but had no effects on cerebellar development in terms of Purkinje cell morphology and the thickness of the internal granular layer and the molecular layer of the *** puberty and adulthood,the thyroid morphological alterations became more pronounced in the TBBPA-treated animals,accompanied by decreased serum thyroid hormone ***,the 50 and 500μg/(kg·day)TBBPA groups showed a significant decrease in the serum level of serotonin,a neurotransmitter associated with anxiety ***,the highest dose group displayed anxiety-like behaviors in the elevated plus-maze test on PND 35,but this neurobehavioral alteration disappeared on PND ***,no changes in neurobehavioral parameters tested were found in TBBPAtreated animals at puberty and ***,all observations show that TBBPA can exert thyroid disrupting effects but has little overt impact on brain development and neurobehaviors in mice,suggesting that thyroid disruption does not necessarily cause overtly adverse neurodevelopmental outcomes.

关键词： Tetrabromobisphenol A Thyroid disruption Brain development Neurobehavior Cerebellum

Linear-fitting-based recursive filtering for nonlinear systems under encoding-decoding mechanism

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Science China(Information Sciences) 2024年第5期67卷 183-196页

作者： Bo JIANG Hongli dong Zhiwei GAO Yuxuan SHEN Fan YANG Artificial Intelligence Energy Research Institute Northeast Petroleum University Heilongjiang Provincial Key Laboratory of Networking and Intelligent Control Sanya Offshore Oil & Gas Research Institute Northeast Petroleum University School of Electrical & Information Engineering Northeast Petroleum University

This paper deals with a recursive filtering problem for a class of discrete time-varying nonlinear networked systems with the encoding-decoding mechanism. The linear fitting method is introduced to handle the nonlinearity. An encoding-decoding mechanism is constructed to describe the data transmission process in wireless communication networks(WCNs). To be specific, the measurement outputs are mapped by a quantizer to unique codewords for transmission in WCNs. Then, the codewords are decoded by the decoder to recover the measurement outputs which are sent to the filter. The processing/encoding delay and network delay have been considered. Firstly, on the premise that the upper bound of the filtering error covariance is minimum, the appropriate filtering gain is calculated. Then, the mean square exponential boundedness of the filtering error is analyzed. Finally, two simulation examples are presented to verify the effectiveness of the proposed algorithm.

关键词： encoding-decoding mechanism uniform quantizer linear fitting networked systems recursive filtering

Anomaly-Resistant Decentralized State Estimation Under Minimum Error Entropy With Fiducial Points for Wide-Area Power Systems

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 74-87页

作者： Bogang Qu Zidong Wang Bo Shen Hongli dong Hongjian Liu the College of Automation Engineering Shanghai University of Electric PowerShanghai 200090China IEEE the Department of Computer Science Brunel University LondonUxbridgeMiddiesex UB83PHUK the College of Information Science and Technology Donghua UniversityShanghai 200051 the Engineering Research Center of Digitalized Textile and Fashion Technology Ministry of EducationShanghai 201620China the Artificial Intelligence Energy Research Institute Northeast Petroleum UniversityDaqing 163318 the Heilongjiang Provincial Key Laboratory of Networking and Intelligent Control Northeast PetroleumDaqing 163318 the Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya 572024China the Key Laboratory of Advanced Perception and Intelligent Control of High-End Equipment Ministry of EducationAnhui Polytechnic UniversityWuhu 2410000 the School of Mathematics and Physics Anhui Polytechnic UniversityWuhu 241000China

This paper investigates the anomaly-resistant decentralized state estimation(SE) problem for a class of wide-area power systems which are divided into several non-overlapping areas connected through transmission lines. Two classes of measurements(i.e., local measurements and edge measurements) are obtained, respectively, from the individual area and the transmission lines. A decentralized state estimator, whose performance is resistant against measurement with anomalies, is designed based on the minimum error entropy with fiducial points(MEEF) criterion. Specifically, 1) An augmented model, which incorporates the local prediction and local measurement, is developed by resorting to the unscented transformation approach and the statistical linearization approach;2) Using the augmented model, an MEEF-based cost function is designed that reflects the local prediction errors of the state and the measurement;and 3) The local estimate is first obtained by minimizing the MEEF-based cost function through a fixed-point iteration and then updated by using the edge measuring information. Finally, simulation experiments with three scenarios are carried out on the IEEE 14-bus system to illustrate the validity of the proposed anomaly-resistant decentralized SE scheme.

关键词： Decentralized state estimation(SE) measurements with anomalies minimum error entropy unscented Kalman filter wide-area power systems

Strengthened and toughened SiHfBCN-based hightemperature resistant adhesive with SiC NWs

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Chinese Journal of Aeronautics 2024年第7期37卷 539-549页

作者： Xingang LUAN Xiyue ZHU Xichao dong Min LI Laifei CHENG Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical UniversityXi’an 710072China

To further improve the performance of binders,a SiHfBCN-based high-temperature resistant adhesive was successfully synthesized by Polymer-Derived Ceramics(PDC)route using TiB2,Polysiloxane(PSO)and short SiC nanowires as *** effect of short SiC nanowires on the adhesive strength at room temperature and high temperature,as well as the reinforcing mechanism was *** with the adhesive without SiC nanowires,after curing(at 170℃)and pyrolysis(at 1000℃)in air,the appropriate adding of SiC nanowires upgrades the room temperature and high temperature(at 1000℃ in air)adhesive strength to(12.50±0.67)MPa(up by about 32%)and(13.11±0.79)MPa(up by about 106%),***,under the synergistic impact of the nanowire bridging,nanowire breaking,nanowire drawing and crack deflection,the optimized adhesive exhibits multi-stage fracture,causing the increscent fracture displacement.

关键词： High-temperature resistant adhesive SiHfBCN SiC NWs Strengthening Toughening

Fast strength-ductility synergistically adjusting of cold spray additive manufactured Cu deposits via electric pulse processing

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Chinese Journal of Aeronautics 2024年第5期37卷 558-569页

作者： dong WU Yaxin XU Wenya LI Xiawei YANG Yu SU State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Friction Welding Technologies School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Electric Pulse Processing(EPP)treatment was innovatively introduced to optimize the strength and ductility of the CSAMed Cu *** results show that EPP is an efficient and fast post-treatment to improve the strength and ductility(within tens of seconds).The larger the pulse current and number of pulses,the better the mechanical ***,this research found that when the heat input determined by pulse current and number of pulses exceeds a certain threshold(pulse current intensity is 2000 A,number of pulses is 10),increasing the number of repeat time could also effectively improve the mechanical properties.A tensile strength of 210 MPa and a ductility of 14.0%could be obtained with reasonable EPP parameters(pulse current intensity is 2000 A,number of pulses is 10,and repeat number is 2),which is similar to those of conventional annealing(e.g.,tensile strength is 272 MPa,elongation is 28.3%).The microstructure evolution analysis shows that EPP can effectively improve the bonding quality between the deposited particles by recrystallization,promote grain growth and the formation of twins,which is the main reason for the improvement of mechanical properties.

关键词： Cold spray additive manufacturing Copper deposit Mechanical property Electric pulse processing Post treatment