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CSEE Journal of Power and Energy Systems 2022年第5期8卷 1457-1467页

作者： ge Chen Biao yan Hongcai zhang Dongdong zhang Yonghua Song State Key Laboratory of Internet of Things for Smart City and Department of Electrical and Computer Engineering University of MacaoMacao 999078China

District cooling system(DCS)provides centralized chilled water to multiple buildings for air conditioning with high energy-efficiency and operational flexibility.It is one of the most popular cooling systems for large buildings in modern cities and an important demand response source for power systems.In order to enhance its energy efficiency and utilize its flexibility,strategic operation is indispensable.However,finding an optimal policy for DCS operation is a challenging task because of the high inter-connectivity among components.The evolution of cooling load uncertainties further increases the difficulties.This paper addresses the aforementioned challenges by proposing a novel optimal power dispatch model for DCS.The proposed model optimizes water temperature and mass flow rates simultaneously to improve the energy efficiency as much as possible.It also explicitly describes the uncertainty accumulation and propagation.Chance-constrained programming is employed to guarantee the cooling service quality.We further propose a more timeefficient formulation to overcome the computational intractability caused by the non-smooth and non-convex constraints.Numerical experiments based on a real DCS confirm that a time-efficient formulation can save about half of solution time with negligible cost increase.

关键词： District cooling system HVAC cooling power dispatch demand-side flexibility chance-constrained programming

Multi-blade rubbing characteristics of the shaft-disk-blade-casing system with large rotation

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 111-136页

作者： Zhiyuan WU Linchuan ZHAO Han yan ge yan Ao CHEN Wenming zhang State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Aerospace Systems Engineering Shanghai 201108China

Blade rubbing faults cause detrimental impact on the operation of aeroengines. Most of the existing studies on blade rubbing in the shaft-disk-blade-casing(SDBC) system have overlooked the elastic deformation of the blade, while some only consider the whirl of the rotor, neglecting its spin. To address these limitations, this paper proposes a dynamic model with large rotation for the SDBC system. The model incorporates the spin and whirl of the rotor, enabling the realistic reproduction of multiblade rubbing faults. To verify the accuracy of the SDBC model with large rotation and demonstrate its capability to effectively consider the rotational effects such as the centrifugal stiffening and gyroscopic effects, the natural characteristics and dynamic responses of the proposed model are compared with those obtained from reported research and experimental results. Furthermore, the effects of the rotating speed, contact stiffness,and blade number on the dynamic characteristics of the SDBC system with multi-blade rubbing are investigated. The results indicate that the phase angle between the rotor deflection and the unbalance excitation force increases with the increasing rotating speed,which significantly influences the rubbing penetration of each blade. The natural frequency of the SDBC system with rubbing constrain can be observed in the acceleration response of the casing and the torsional response of the shaft, and the frequency is related to the contact stiffness. Moreover, the vibration amplitude increases significantly with the product of the blade number under rubbing, and the rotating frequency approaches the natural frequency of the SDBC system. The proposed model can provide valuable insight for the fault diagnosis of rubbing in bladed rotating machinery.

关键词： shaft-disk-blade-casing(SDBC) large rotation spin and whirl multi-blade rubbing rotational effect

Molecular dynamics simulation on the rejuvenation effects of waste cooking oil on aged asphalt binder

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Journal of Traffic and Transportation Engineering(English Edition) 2022年第5期9卷 795-807页

作者： Shiao yan Changjun Zhou Jian zhang ge Li School of Transportation&Logistics Dalian University of TechnologyDalian 116024China Tongren City Transportation Bureau Tongren 554300China

Waste cooking oil(WCO)has received attention on rejuvenating aged asphalt binder widely in recent years.This study evaluated the rejuvenation effects of WCO on aged asphalt binder on the micro-scale using molecular dynamics(MD)simulation.First,the representative molecules of WCO and asphalt binders were selected.The molecular mixture model was then developed.The thermodynamic properties were investigated,including density,cohesive energy density,solubility parameter,and surface free energy.The results show that WCO can restore the thermodynamic properties of aged asphalt binder to some extent and WCO has different influences on electrostatic interactions and van der Waals effects.From the diffusion behavior and molecular structure of asphalt binder,WCO can improve the molecular mobility and restore the colloidal structure.Besides,the adhesion work and moisture susceptibility of asphalt binder-aggregate interfaces(calcite and quartz)were evaluated.The results show that WCO can improve adhesion work between asphalt binder and aggregates since WCO can change molecular structure of asphalt binders and certain adhesion work exists between WCO and aggregates.Also,it can mitigate the moisture susceptibility of asphalt binder-aggregate interfaces(calcite and quartz).The study demonstrates that the MD simulation can help to understand the rejuvenation effects of WCO on aged asphalt binder on the micro-scale.

关键词： Waste cooking oil Aged asphalt binder Rejuvenation Molecular dynamics Micro-scale

New Result on Delay-dependent Stability for Markovian Jump Time-delay Systems With Partial Information on Transition Probabilities

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IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1499-1505页

作者： yan zhang Ke Lou Yuan ge the College of Electrical Engineering Anhui Key Laboratory of Detection Technology and Energy Saving Devices Anhui Polytechnic University

This paper focuses on the delay-dependent stability for a kind of Markovian jump time-delay systems(MJTDSs),whose transition rates are incompletely known. In order to reduce the computational complexity and achieve better performance,auxiliary function-based double integral inequality is combined with extended Wirtinger's inequality and Jensen inequality to deal with the double integral and the triple integral in augmented Lyapunov-Krasovskii function(ALKF) and their weak infinitesimal generator respectively, the more accurate approximation bounds with a fewer variables are derived. As a result, less conservative stability criteria are proposed in this paper. Finally,numerical examples are given to show the effectiveness and the merits of the proposed method.

关键词： Auxiliary function-based double integral inequality delay-dependent stability Markovian jump time-delay systems(MJTDSs) unknown transition rates

Determination of Fe,Ni,Cu,Zn,Cd and Pb in seawater by isotope dilution automatic solid-phase extraction—ICP-MS

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Acta Oceanologica Sinica 2022年第8期41卷 129-136页

作者： Yuncong ge Ruifeng zhang Ziyuan Jiang Zhan Shen Maojun yan School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China Key Laboratory for Polar Science of Ministry of Natural Resources Polar Research Institute of ChinaShanghai 200136China

A thorough understanding of the biogeochemical cycling of trace metals in the ocean is crucial because of the important role these elements play in regulating metabolism in marine biotas and thus,the climate.However,a precise and accurate analysis of trace metals in seawater is difficult because they are present at extremely low concentrations in a high salt matrix.In this study,we report an analytical method for the preconcentration and separation of six trace metals,Fe,Ni,Cu,Zn,Cd and Pb,in seawater using a sea FAST automatic solid-phase extraction device,analysis by a triple quadrupole collision/reaction technique with inductively coupled plasma mass spectrometry(ICP-MS),and quantification by the isotope dilution technique.A small volume(10 m L)of seawater sample was mixed with a multi-element isotope spike and subjected to sea FAST procedures.The preconcentrate solution was then analyzed using the optimized collision/reaction cell mode of ICP-MS,with NH_(3)gas for Fe and Cd with a flow rate of 0.22 m L/min and He for Ni,Cu,Zn and Pb with a flow rate of 4.0 m L/min.The procedure blanks were 130 pmol/L,3.0 pmol/L,6.8 pmol/L,37 pmol/L,0.29 pmol/L and 0.42 pmol/L,for Fe,Ni,Cu,Zn,Cd and Pb,respectively.The method was validated using five reference materials(SLRs-6,SLEW-3,CASS-6,NASS-7 and geOTRACE-GSC),and our results were consistent with the consensus values.The method was further validated by measuring full-water-column seawater samples from the subtropical Northwest Pacific Ocean,and our results demonstrated good oceanic consistency.

关键词： seaFAST trace metals isotope dilution seawater ICP-MS

Reveal heterogeneous motion states in single nanoparticle trajectory using its own history

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Science China Chemistry 2021年第2期64卷 302-312页

作者： Hansen Zhao Feng ge Sichun zhang Xinrong zhang yan He Department of Chemistry Tsinghua UniversityBeijing100084China

Single particle tracking(SPT)has long been utilized for investigation of complex system dynamics such as nanoparticle-cell interaction,however,the analysis of individual particle motions is always a difficult issue.Existing methods treat each data point or fragment on the recorded trajectory as an isolated"atom"and determine their relationship based on externally predefined models or physical states,which inevitably lead to oversimplification of the associated spatiotemporal complexity.Herein,inspired by the historical analysis in social science,we propose a modeless preprocessing framework for SPT analysis based on the"history"of the particle.This new strategy consists of 3 steps:(1)assign a"history"to each data point and construct successive overlapped historical vectors;(2)perform unsupervised clustering in the vector space to find their relative differences;(3)project differences back to the trajectory by coloring each point accordingly for visualization.As a result,the inner heterogeneity of the particle motion self-emerges as a colored trajectory,exhibiting a global picture of the local state transitions and providing valuable information for further model-based analysis.Since the complexity issues at various spatiotemporal scales have attracted increasing attention,and individual objects such as single molecules,cells,vehicles and even stars in the universe could all be treated as"single particles",this presuppositionless data preprocessing approach could help the investigations of many complex systems in fundamental research.

关键词： single particle tracking nanoparticle machine learning

Comparison of Effects of Liuzijue Exercise and Conventional Respiratory Training on Patients after Cardiac Surgery:A Randomized Controlled Trial

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Chinese Journal of Integrative Medicine 2023年第7期29卷 579-589页

作者： zhang Qiao-li ge Min CHEN Cheng FAN Fu-dong JIN yan zhang Ning WANG Lei Department of Rehabilitation Medicine Nanjing Drum Tower HospitalClinical College of Nanjing University of Chinese MedicineNanjing 210008China Department of Rehabilitation College of Acupuncture and Moxibustion and Massage Health Preservation and RehabilitationNanjing University of Chinese MedicineNanjing 210023China Department of Cardio-Thoracic Surgery Nanjing Drum Tower Hospitalthe Affiliated Hospital of Nanjing University Medical SchoolNanjing 210008China Department of Ultrasound Nanjing Drum Tower Hospitalthe Affi liated Hospital of Nanjing University Medical SchoolNanjing 210008China

Objective To evaluate the feasibility and safety of Liuzijue exercise(LE)for the clinical effect in patients after cardiac surgery.Methods Totally 120 patients who underwent cardiac surgery and were admitted to the Cardiothoracic Intensive Care Unit of Nanjing Drum Tower Hospital between July and Oclober,2022 were allocated to the LE group,the conventional respiratory training(CRT)group,and the control group by a random number table at a ratio of 1:1:1;40 patients in each group.All patients received routine treatment and cardiac rehabilitation.LE group and CRT group respectively performed LE and CRT once a day for 30 min for 7 days.Control group did not receive specialized respiratory training.The forced vital capacity,forced expiratory volume in 1 s,peak inspiratory flow rate,peak expiratory flow rate,maximum inspiratory pressure,maximum expiratory pressure,modified Barthel index(MBI),and Hamilton Rating Scale for Anxiety(HAM-A)were evaluated before,after 3 and 7 days of intervention.In addition,the postoperative length of hospital stay(LOS)and the adverse events that occurred during the intervention period were compared.Results A total of 107 patients completed the study,120 patients were included in the analysis.After 3 days of intervention,the pulmonary function,respiratory muscle strength,MBI and HAM-A of all 3 groups improved compared with that before the intervention(P<0.05 or P<0.01).Compared with the control group,pulmonary function and respiratory muscle strength were significantly improved in the CRT and LE groups(P<0.05 or P<0.01).MBI and HAM-A were significantly improved in the LE group compared with the control and CRT groups(P<0.05 or P<0.01).On the 7th day after intervention,the difference was still statistically significant(P<0.01),and was significantly different from that on the 3rd day(P<0.05 or P<0.01).In addition,on the 7th day of intervention,the pulmonary function and respiratory muscle strength in the LE group were significantly improved compared with those in the CRT group(P<0.01).MBI and

关键词： Liuzijue exercise pulmonary function Liuzijue exercise pulmonary function respiratory muscle strength activities of daily living respiratory muscle strength activities of daily living anxiety cardiac surgery

Targeting and signaling of Rho of plants guanosine triphosphatases require synergistic interaction between guanine nucleotide inhibitor and vesicular trafficking

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Journal of Integrative Plant Biology 2020年第10期62卷 1484-1499页

作者： Fu-Rong ge Sen Chai Sha Li yan zhang State Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTai'an 271018China Shandong Institute of Pomology Shandong Academy of Agricultural SciencesTai'an 271000China

Most eukaryotic cells are polarized.Common toolbox regulating cell polarization includes Rho gua-nosine triphosphatases(GTPases),in which spatio-temporal activation is regulated by a plethora of reg-ulators.Rho of plants(ROPs)are the only Rho GTPases in plants.Although vesicular trafficking was hinted in the regulation of ROPs,it was unclear where vesicle-carried ROP starts,whether it is dynamically regulated,and which components participate in vesicle-mediated ROP targeting.In addition,although vesicle trafficking and guanine nucleotide inhibitor(GDI)pathways in Rho signaling have been extensively studied in yeast,it is unknown whether the two pathways interplay.Unclear are also cellular and developmental con-sequences of their interaction in multicellular organisms.Here,we show that the dynamic targeting of ROP through vesicles requires coat protein complexⅡand ADP-ribosylation factor 1-mediated post-Golgi trafficking.Trafficking of vesicle-carried ROPs between the plasma membrane and the trans-Golgi network is mediated through adaptor protein 1 and sterol-mediated endocytosis.Finally,we show that GDI and vesicle trafficking synergistically regulate cell polar-ization and ROP targeting,suggesting that the estab-lishment and maintenance of cell polarity is regulated by an evolutionarily conserved mechanism.

关键词： synergistic interaction traffic

Stability Analysis and Control of DC Distribution System with Electric Vehicles

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Energy Engineering 2023年第3期120卷 633-647页

作者： Zhijie Zheng Song zhang Xiaolei zhang Bo yang Fang yan Xiaoning ge State Grid Shandong Electric Power Company Economic and Technological Research Institute JinanChina State Grid Shandong Electric Power Company Limited JinanChina State Nuclear Electric Power Planning Design&Research Institute Company Limited BeijingChina

The DC distribution network system equipped with a large number of power electronic equipment exhibits weak damping characteristics and is prone to low-frequency and high-frequency unstable oscillations.The current interpretation of the oscillation mechanism has not been unified.Firstly,this paper established the complete statespace model of the distribution system consisting of a large number of electric vehicles,characteristic equation of the distribution network system is derived by establishing a state-space model,and simplified reduced-order equations describing the low-frequency oscillation and the high-frequency oscillation are obtained.Secondly,based on eigenvalue analysis,the oscillation modes and the influence of the key system parameters on the oscillation mode are studied.Besides,impacts of key factors,such as distribution network connection topology and number of dynamic loads,have been discussed to suppress oscillatory instability caused by inappropriate design or dynamic interactions.Finally,using the DC distribution example system,through model calculation and time-domain simulation analysis,the correctness of the aforementioned analysis is verified.

关键词： DC distribution network system oscillation instability reduced-order equivalent model damping control sensitivity analysis

An Adversarial Attack on Salient Regions of Traffic Sign

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Automotive Innovation 2023年第2期6卷 190-203页

作者： Jun yan Huilin Yin Bin Ye Wanchen ge Hao zhang gerhard Rigoll School of Electronic and Information Engineering Tongji UniversityCaoan Gonglu StreetShanghai 201804China Ambarella Co.Ltd Fangdian RoadShanghai 201204China Institute for Human‑Machine Communication Technical University of MunichArcisstraβeMunich D‑80333Germany

The state-of-the-art deep neural networks are vulnerable to the attacks of adversarial examples with small-magnitude per-turbations.In the field of deep-learning-based automated driving,such adversarial attack threats testify to the weakness of AI models.This limitation can lead to severe issues regarding the safety of the intended functionality(SOTIF)in automated driving.From the perspective of causality,the adversarial attacks can be regarded as confounding effects with spurious corre-lations established by the non-causal features.However,few previous research works are devoted to building the relationship between adversarial examples,causality,and SOTIF.This paper proposes a robust physical adversarial perturbation genera-tion method that aims at the salient image regions of the targeted attack class with the guidance of class activation mapping(CAM).With the utilization of CAM,the maximization of the confounding effects can be achieved through the intermediate variable of the front-door criterion between images and targeted attack labels.In the simulation experiment,the proposed method achieved a 94.6%targeted attack success rate(ASR)on the released dataset when the speed-speed-limit-60 km/h(speed-limit-60)signs could be attacked as speed-speed-limit-80 km/h(speed-limit-80)signs.In the real physical experiment,the targeted ASR is 75%and the untargeted ASR is 100%.Besides the state-of-the-art attack result,a detailed experiment is implemented to evaluate the performance of the proposed method under low resolutions,diverse optimizers,and multifarious defense methods.The code and data are released at the repository:https://***/yebin999/rp2-with-cam.

关键词： Automated driving Adversarial examples Safety of the intended functionality(SOTIF) Classification