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Comparative analysis of time series neural network methods for three-way catalyst modeling

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Energy and AI 2024年第3期17卷 220-232页

作者： Zhuoxiao yao Tao chen Weipeng Lin Yifang Feng Zengchun Wei State Key Laboratory of Engines Tianjin University135 Yaguan RdTianjin 300350China

Relative Oxygen Level of the Three-Way Catalyst is an important parameter that affects the conversion efficiency of pollutants. ROL is a time-varying hidden state variable that is difficult to directly observe in practice. Therefore, it is common to use a method of clearing oxygen storage to simplify control in vehicles. However, this method negates the positive effects of ROL on pollutant treatment. ROL can be indirectly observed through modeling methods. Chemical modeling methods involve extensive computational requirements that cannot meet the demands of practical control. In contrast, time-series neural networks offer computational speed advantages when dealing with similar problems. Therefore, the ROL observation models using both NARX and LSTM neural networks are developed and compared in this study. The results indicate that the NARX neural network exhibits higher precision with a smaller number of neurons and time steps. The LSTM neural network demonstrates greater stability when dealing with data error fluctuations. In practical applications, the ROL model can monitor the TWC operating status and assist in the development of intelligent pollutant aftertreatment control strategies.

关键词： Relative Oxygen Level Neural network modeling long short-term memory Nonlinear auto-regressive network with eXogenous inputs

Online learning-based model predictive trajectory control forconnected and autonomous vehicles: Modeling and physical tests

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Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2024年第2期7卷 86-96页

作者： Qianwen Li Peng Zhang Handong yao Zhiwei chen Xiaopeng Li School of Environmental CivilAgricultural and Mechanical EngineeringUniversity of GeorgiaAthens 30602USA Department of Civil and Environmental Engineering University of Wisconsin–MadisonMadison 53706USA Department of Civil Architecturaland Environmental EngineeringDrexel UniversityPhiladelphia 19104USA

Motivated by the promising benefits of connected and autonomous vehicles (CAVs) in improving fuelefficiency, mitigating congestion, and enhancing safety, numerous theoretical models have been proposed to plan CAVmultiple-step trajectories (time–specific speed/location trajectories) to accomplish various operations. However, limitedefforts have been made to develop proper trajectory control techniques to regulate vehicle movements to follow multiplesteptrajectories and test the performance of theoretical trajectory planning models with field experiments. Without aneffective control method, the benefits of theoretical models for CAV trajectory planning can be difficult to harvest. This studyproposes an online learning-based model predictive vehicle trajectory control structure to follow time–specific speed andlocation profiles. Unlike single-step controllers that are dominantly used in the literature, a multiple-step model predictivecontroller is adopted to control the vehicle’s longitudinal movements for higher accuracy. The model predictive controlleroutput (speed) cannot be interpreted by vehicles. A reinforcement learning agent is used to convert the speed value to thevehicle’s direct control variable (i.e., throttle/brake). The reinforcement learning agent captures real-time changes in theoperating environment. This is valuable in saving parameter calibration resources and improving trajectory control accuracy.A line tracking controller keeps vehicles on track. The proposed control structure is tested using reduced-scale robot *** adaptivity of the proposed control structure is demonstrated by changing the vehicle load. Then, experiments on twofundamental CAV platoon operations (i.e., platooning and split) show the effectiveness of the proposed trajectory controlstructure in regulating robot movements to follow time-specific reference trajectories.

关键词： connected and autonomous vehicles(CAVs) reinforcement learning physical tests time-specific speed and location longitudinal and lateral control

Tool Wear State Recognition with Deep Transfer Learning Based on Spindle Vibration for Milling Process

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2825-2844页

作者： Qixin Lan Binqiang chen Bin yao Wangpeng He School of Aerospace Engineering Xiamen UniversityXiamen361005China School of Aerospace Science and Technology Xidian UniversityXi’an710126China

The wear of metal cutting tools will progressively rise as the cutting time goes on. Wearing heavily on the toolwill generate significant noise and vibration, negatively impacting the accuracy of the forming and the surfaceintegrity of the workpiece. Hence, during the cutting process, it is imperative to continually monitor the tool wearstate andpromptly replace anyheavilyworn tools toguarantee thequality of the *** conventional tool wearmonitoring models, which are based on machine learning, are specifically built for the intended cutting ***, these models require retraining when the cutting conditions undergo any changes. This method has noapplication value if the cutting conditions frequently change. This manuscript proposes a method for monitoringtool wear basedonunsuperviseddeep transfer learning. Due to the similarity of the tool wear process under varyingworking conditions, a tool wear recognitionmodel that can adapt to both current and previous working conditionshas been developed by utilizing cutting monitoring data from history. To extract and classify cutting vibrationsignals, the unsupervised deep transfer learning network comprises a one-dimensional (1D) convolutional neuralnetwork (CNN) with a multi-layer perceptron (MLP). To achieve distribution alignment of deep features throughthe maximum mean discrepancy algorithm, a domain adaptive layer is embedded in the penultimate layer of thenetwork. A platformformonitoring tool wear during endmilling has been constructed. The proposedmethod wasverified through the execution of a full life test of end milling under multiple working conditions with a Cr12MoVsteel workpiece. Our experiments demonstrate that the transfer learning model maintains a classification accuracyof over 80%. In comparisonwith the most advanced tool wearmonitoring methods, the presentedmodel guaranteessuperior performance in the target domains.

关键词： Multi-working conditions tool wear state recognition unsupervised transfer learning domain adaptation maximum mean discrepancy(MMD)

Synergy of sodium doping and nitrogen defects in carbon nitride for promoted photocatalytic synthesis of hydrogen peroxide

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Chinese Chemical Letters 2024年第8期35卷 324-329页

作者： Fabrice Nelly Habarugira Ducheng yao Wei Miao chengcheng Chu Zhong chen Shun Mao College of Environmental Science and Engineering State Key Laboratory of Pollution Control and Resource ReuseTongji UniversityShanghai 200092China Baowu Water Technology Co. Ltd.Research InstituteShanghai 201999China

Photocatalytic synthesis of hydrogen peroxide has gradually become a promising method for in-situ pro-duction of hydrogen peroxide,which relies on sustainable solar ***,the commonly used photocatalyst,i.e.,carbon nitride(CN),still suffers from the drawbacks of narrow light absorption range and fast charge ***,we report a facile method to introduce nitrogen defects into carbon nitride together with sodium *** adjusting the ratio of sodium dicyandiamide,the band gap of carbon nitride can be controlled,while the carrier separation and transfer ability of carbon nitride is *** modified CN with sodium doping and nitrogen defect(SD-CN)demonstrates outstanding H_(2)O_(2)pro-duction performance(H_(2)O_(2)yield rate of 297.2μmol L^(−1)h^(−1))under visible light irradiation,which is approximately 9.8 times higher than that of pristine *** work deepens the understanding of the coordinated effect of structural defect and element doping of carbon nitride on the photocatalytic H_(2)O_(2)production performance,and provides new insight into the design of photocatalytic system for efficient production of H_(2)O_(2).

关键词： Photocatalysis H_(2)O_(2)evolution Sodium doping Nitrogen defect Metal-free catalyst

Strong metal-support interaction between AuPd nanoparticles and oxygen-rich defect ZrO_(2) for enhanced catalytic 5-hydroxymethylfurfural oxidation

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Chinese Chemical Letters 2024年第2期35卷 507-511页

作者： Yunlei Zhang Yiran Liu Wen Guan Mengxue Cao yao chen Pengwei Huo Institute of Green Chemistry and Chemical Technology School of Chemistry and Chemical EngineeringJiangsu UniversityZhenjiang 212013China School of the Environment and Safety Jiangsu UniversityZhenjiang 212013China

The unique properties of metal oxide surfaces,crystal surfaces and defects play vital roles in biomass upgrading *** this work,hierarchical porous bowl-shaped ZrO_(2)(HB-ZrO_(2))with mixed crystal phase was designed and employed as the support for loading AuPd bimetal with different proportions to synthesize AuPd/HB-ZrO_(2) *** effects of surface chemistry,oxygen defects,bimetal interaction and metal-support interaction of AuPd/HB-ZrO_(2) on catalytic performance for the selective oxidation of 5-hydroxymethylfurfural(HMF)to 2,5-furandicarboxylic acid(FDCA)were systematically *** Au 2 Pd1/HB-ZrO_(2) catalyst afforded a satisfactory FDCA yield of 99.9%from HMF oxidation using O_(2) as the oxidant in water,accompanied with an excellent FDCA productivity at 97.6 mmol g^(−1) h^(−1).This work offers fresh insights into rationally designing efficient catalysts with oxygen-rich defects for the catalytic upgrading of biomass platform chemicals.

关键词： 5-Hydroxymethylfurfural oxidation 2,5-Furandicarboxylic acid Oxygen-rich defect ZrO_(2) AuPd bimetal Bowl-shaped structure

A facile strategy for large-scale production of 2D nanosheets exfoliated by three-roll milling

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Journal of Advanced Ceramics 2024年第1期13卷 11-18页

作者： Xin Wang Yang Xia Juntong Huang yao Su Zhi chen Linlin chen Zhaohui Wu Zhijun Feng Huiyong Yang Xibao Li School of Materials Science and Engineering Nanchang Hangkong UniversityNanchang 330063China

Two-dimensional(2D)nanomaterials,such as graphene,MoS_(2),and MAX,have attracted increasing research attention in recent years due to their unique structural and performance ***,their complex production processes and equipment requirements are significant issues affecting their widespread ***,with an exfoliation strategy using three-roll milling,we present a simple,cost-effective,and extensible method to produce multilayer graphene,BN,MoS_(2),and Ti_(3)AlC_(2) *** roller and phenolic resin created three kinds of forces on the layered 2D materials,i.e.,shear forces,compressive forces,and adhesive forces,which exfoliated layered materials from their edges and surfaces into ***,the exfoliated materials were ultrasonically washed with alcohol,treated with ultrasonic vibration,and centrifuged to obtain 2D *** easy operation and high yield are attractive for research based on the construction of high-performance 2D nanosheet-based devices at low ***,the obtained multilayer graphene and MoS_(2) nanosheets were used as anode materials of sodium/potassium-ion batteries,respectively,to test their electrochemical *** performances are obtained compared with their primary bulk materials.

关键词： two-dimensional(2D)nanosheets exfoliation three-roll milling(TRM) sodium/potassium-ion batteries

Optimized Auxiliary Frequency Control of Wind Farm Based on Piecewise Reduced-order Frequency Response Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 791-802页

作者： Xu Zhang chen Zhao Junchao Ma long Zhang Dan Sun chenxu Wang Yan Peng Heng Nian the School of Electrical Engineering Zhejiang UniversityHangzhou 310058China Electric Power Research Institute of State Grid Zhejiang Electric Power Corporation Hangzhou 310014China

With the increasing wind power penetration in the power system,the auxiliary frequency control(AFC)of wind farm(WF)has been widely *** traditional system frequency response(SFR)model is not suitable for the wind power generation system due to its poor accuracy and *** this paper,a piecewise reduced-order frequency response(PROFR)model is proposed,and an optimized auxiliary frequency control(O-AFC)scheme of WF based on the P-ROFR model is ***,a full-order frequency response model considering the change in operating point of wind turbine is established to improve the *** order to simplify the fullorder model,a P-ROFR model with second-order structure and high accuracy at each frequency response stage is *** on the proposed P-ROFR model,the relationship between the frequency response indexes and the auxiliary frequency controller coefficients is expressed ***,an OAFC scheme with the derived explicit expression as the optimization objective is proposed in order to improve the frequency support capability on the premise of ensuring the full release of the rotor kinetic energy and the full use of the effect of time delay on frequency ***,the effectiveness of the proposed P-ROFR model and the performance of the proposed OAFC scheme are verified by simulation studies.

关键词： Frequency response piecewise reduced-order wind farm auxiliary frequency control

Photo-responsive functional materials based on light-driven molecular motors

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Light(Science & Applications) 2024年第3期13卷 407-420页

作者： Yanping Deng Guiying long Yang Zhang Wei Zhao Guofu Zhou Ben L.Feringa Jiawen chen SCNU-UG International Joint Laboratory of Molecular Science and Displays National Center for International Research on Green OptoelectronicsSouth China Normal UniversityGuangzhou 510006China Stratingh Institute for Chemistry University of GroningenNijenborgh 49747AG GroningenThe Netherlands

In the past two decades,the research and development of light-triggered molecular machines have mainly focused on developing molecular devices at the nanoscale.A key scientific issue in the field is how to amplify the controlled motion of molecules at the nanoscale along multiple length scales,such as the mesoscopic or the macroscopic scale,or in a more practical perspective,how to convert molecular motion into changes of properties of a macroscopic ***-driven molecular motors are able to perform repetitive unidirectional rotation upon irradiation,which offers unique opportunities for responsive macroscopic *** several reviews that focus on the design,synthesis and operation of the motors at the nanoscale,photo-responsive macroscopic materials based on light-driven molecular motors have not been comprehensively *** the present review,we first discuss the strategy of confining absolute molecular rotation into relative rotation by grafting motors on ***,examples of self-assemble motors in supramolecular polymers with high internal order are ***,we will focus on building of motors in a covalently linked system such as polymeric gels and polymeric liquid crystals to generate complex responsive ***,a perspective toward future developments and opportunities is *** review helps us getting a more and more clear picture and understanding on how complex movement can be programmed in light-responsive systems and how man-made adaptive materials can be invented,which can serve as an important guideline for further design of complex and advanced responsive materials.

关键词： functions materials material

Human umbilical cord mesenchymal stem cells derivedexosomes on VEGF-A in hypoxic-induced mice retinal astrocytes and mice model of retinopathy of prematurity

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International Journal of Ophthalmology(English edition) 2024年第7期17卷 1238-1247页

作者： Xiao-Tian Zhang Bo-Wen Zhao Yuan-long Zhang Song chen Tianjin Eye Hospital Tianjin 300020China Tianjin Key Lab of Ophthalmology and Visual Science Tianjin 300020China

AIM:To observe the effect of human umbilical cord mesenchymal stem cells(hUCMSCs)secretions on the relevant factors in mouse retinal astrocytes,and to investigate the effect of hUCMSCs on the expression of vascular endothelial growth factor-A(VEGF-A)and to observe the therapeutic effect on the mouse model of retinopathy of prematurity(ROP).METHODS:Cultured hUCMSCs and extracted exosomes from them and then retinal astrocytes were divided into control group and hypoxia *** assay,flow cytometry,reverse transcription-polymerase chain reaction(RT-PCR)and Western blot were used to detect related *** mechanisms by which hUCMSCs exosomes affect VEGF-A expression in hypoxia-induced mouse retinal astrocytes were *** last,the efficacy of exosomes of UCMSCs in a mouse ROP model was ***6 was used to comprehensively process data ***:The secretion was successfully extracted from the culture supernatant of hUCMSCs by gradient *** oxygen species(ROS)and hypoxia inducible factor-1α(HIF-1α)of mice retinal astrocytes under different hypoxia time and the expression level of VEGF-A protein and VEGF-A mRNA increased,and the ROP cell model was established after 6h of *** secretions of medium and high concentrations of hUCMSCs can reduce ROS and HIF-1α,the expression levels of VEGF-A protein and VEGF-A mRNA are statistically significant and concentration *** with the ROP cell model group,the expression of phosphatidylinositol 3-kinase(PI3K)/protein kinase B(AKT)/mammalian target of rapamycin(mTOR)signal pathway related factors in the hUCMSCs exocrine group is significantly *** intravitreal injection of the secretions of medium and high concentrations of hUCMSCs can reduce VEGF-A and HIF-1αin ROP model *** staining shows that the number of retinal neovascularization in ROP mice decreases with the increase of the dose of hUCMSCs ***:In a hypoxia induced

关键词： human umbilical cord mesenchymal stem cells retinal astrocytes retinopathy of prematurity vascular endothelial growth factor hypoxia inducible factor