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Pseudo-active actuators:A concept analysis

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International Journal of Mechanical System Dynamics 2021年第2期1卷 230-247页

作者： Xianxu Bai guannan he Department of Vehicle Engineering Laboratory for Adaptive Structures and Intelligent Systems(LASIS)Hefei University of TechnologyHefeiChina

The superior performance of active vibration control systems largely depends on the four-quadrant controllable execution capability in the available force-velocity diagram of active actuators.Although semi-active vibration control systems have the advantages of low energy consumption,simple structure,and high reliability,the system performance is not comparable to active control systems,due to the partial capability in only the first and third quadrants.On the basis of the comprehensive advantages of active and semi-active actuators,to reform the design philosophy of semi-active actuators to realize pseudo-active actuators that have both mechanical properties of active actuators and energy consumption advantages of semi-active actuators,that is,new semi-active actuators with four-quadrant controllable execution capability,will very likely cause a revolution in the related fields of mechanical design and system control.The basic design principle of pseudo-active actuators that use semi-active controllable actuators to achieve active actuator performance in the way of conceptual analysis is proposed.The proposed pseudo-active actuators should consist of two half-four-quadrant actuators,that is,one is for the first and third quadrants and the other one for the second and fourth quadrants.This study employs two semi-active controllable damping actuators and one mechanical compensation mechanism.One of the actuators provides the damping force in the first and third quadrants,and the other one combining with the mechanical compensation mechanism is for the second and fourth quadrants.A global mathematical model of the proposed actuator is established to describe the four different operational modes of the proposed actuator.It is proved that the two operational modes of the proposed actuator can realize active vibration control,and a case study of realizing active control is presented.The other two operational modes are compared with the conventional two-degree-of-freedom model.More specifically,the application cases of

关键词： four-quadrant pseudo-active actuator pseudo-active suspension semi-active actuator topology

Preparation and photocatalytic properties of porous C and N co-doped TiO_2 deposited on brick by a fast, one-step microwave irradiation method

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Journal of Environmental Sciences 2017年第10期29卷 24-32页

作者： Fangzhou Li Jiangshan Zhou Chun Du Wei Li Yinzhen Wang guannan he Qinyu he South China Normal University School of Physics & Telecommunication Engineering

A one-step microwave irradiation method was used to deposit carbon and nitrogen co-doped TiO2（（C, N）-TiO2） on commercial brick（（C, N）-TiO2/brick）. The as-prepared samples were characterized by X-ray diffraction, ultraviolet–visible（UV–vis） diffuse reflectance spectroscopy, photoluminescence spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy（SEM）. A selective technique was also used to investigate the concentration of hydroxyl radicals during UV–vis irradiation of the Methyl Orange solution with the as-prepared samples. The C and N dopants enhanced visible light absorption and provided a longer lifetime for the photo-generated electron–hole pairs. The SEM images showed that the as-prepared sample is porous. The dark adsorption and photodegradation test for（C, N）-TiO2/brick showed good photodegradation and good recyclability. The best photodegradation rate was 94% after 2 hr. The maximum degradation rate was maintained even after the 6th cycle. The good photocatalytic properties are attributed to the enhanced visible light absorption, enhanced pollutant adsorption arising from the porous structure of the（C, N）-TiO2 thin film, and longer lifetime of the photo-generated electron–hole pairs.（C, N）-TiO2/brick should have potential commercial applications in photodegradation processes because of its low cost, good photodegradation, and excellent recyclability.

关键词：（C,N）-TiO2/brick hybridization Low cost Longer lifetime Good photocatalytic properties Good recyclability

Conditional Generative Adversarial Network Enabled Localized Stress Recovery of Periodic Composites

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 957-974页

作者： Chengkan Xu Xiaofei Wang Yixuan Li guannan Wang he Zhang Transportation and Municipal Engineering Institute Powerchina Huadong Engineering CorporationHangzhou310014China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou310058China Anhui Transport Consulting&Design Institute Co. Ltd.Hefei230088China Center for Balance Architecture Zhejiang UniversityHangzhou310058China

Structural damage in heterogeneousmaterials typically originates frommicrostructures where stress concentration occurs.Therefore,evaluating the magnitude and location of localized stress distributions within microstructures under external loading is crucial.Repeating unit cells(RUCs)are commonly used to represent microstructural details and homogenize the effective response of composites.This work develops a machine learning-based micromechanics tool to accurately predict the stress distributions of extracted RUCs.The locally exact homogenization theory efficiently generates the microstructural stresses of RUCs with a wide range of parameters,including volume fraction,fiber/matrix property ratio,fiber shapes,and loading direction.Subsequently,the conditional generative adversarial network(cGAN)is employed and constructed as a surrogate model to establish the statistical correlation between these parameters and the corresponding localized stresses.The stresses predicted by cGAN are validated against the remaining true data not used for training,showing good agreement.This work demonstrates that the cGAN-based micromechanics tool effectively captures the local responses of composite RUCs.It can be used for predicting potential crack initiations starting from microstructures and evaluating the effective behavior of periodic composites.

关键词： Periodic composites localized stress recovery conditional generative adversarial network

Mechanism of PARP inhibitor resistance and potential overcoming strategies

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Genes & Diseases 2024年第1期11卷 306-320页

作者： Xiaoyu Fu Ping Li Qi Zhou Ruyuan he guannan Wang Shiya Zhu Amir Bagheri Gary Kupfer Huadong Pei Juanjuan Li Department of Oncology Georgetown Lombardi Comprehensive Cancer CenterGeorgetown University Medical CenterWashingtonDC 20057USA Department of Breast and Thyroid Surgery Renmin Hospital of Wuhan UniversityWuhanHubei 430060China Cancer Center Renmin Hospital of Wuhan UniversityWuhanHubei 430060China Department of Thoracic Surgery Renmin Hospital of Wuhan UniversityWuhanHubei 430060China

PARP inhibitors(PARPi)are a kind of cancer therapy that targets poly(ADP-ribose)polymerase.PARPi is the first clinically approved drug to exert synthetic lethality by obstruct-ing the DNA single-strand break repair process.Despite the significant therapeutic effect in pa-tients with homologous recombination(HR)repair deficiency,innate and acquired resistance to PARPi is a main challenge in the clinic.In this review,we mainly discussed the underlying mechanisms of PARPi resistance and summarized the promising solutions to overcome PARPi resistance,aiming at extending PARPi application and improving patient outcomes.

关键词： Drug resistance Homologous recombination PARP PARP inhibitor Poly(ADP-ribose)polymerase

Maximum Weighted Independent Set Based RFID Reader Anti-Collision Protocol

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Maximum Weighted Independent Set Based RFID Reader Anti-Coll...

H∞ Robustness for Distributed Control in Autonomous Microgrids Considering Cyber Disturbances

第三十九届中国控制会议

作者： Zhonghua Li guannan he IEEE School of Intelligent Systems Engineering Sun Yat-sen University School of Electronics and Information Technology Sun Yat-sen University

In a radio frequency identification（RFID） application, mutual interference may happen when adjacent readers interrogate tags simultaneously. As a result, the performance of the RFID system decreases. This effect is called reader collision. To mitigate or remove the reader collision, some researchers proposed various RFID reader anti-collision protocols, such as the family of neighbor-friendly reader anti-collision（NFRA） protocols. This paper attempts to convert the reader collision problem into a graph optimization problem solved by using the maximum weighted independent set（MWIS） theory, and further proposes an MWIS-based RFID reader anti-collision protocol（NFRA-MWIS） by inheriting the framework of NFRA and absorbing the distributed greedy approximation（DistGreedy） algorithm. The numerical simulations indicate that the proposed NFRA-MWIS outperforms several NFRA family protocols. Especially, in some cases, NFRA-MWIS harvests the improvements of more than 24% and 34% in average efficiency and single-round efficiency, respectively.

关键词： distributed greedy approximation maximum weighted independent set neighbor-friendly reader anti-collision number of tags reader collision RFID

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 696-706页

作者： Ge Cao guannan Lou Wei Gu Lina Sheng School of Electrical Engineering Southeast UniversityNanjing 210096China

The physical connections and logical relationships between microgrids and communication networks allow microgrids to develop into typical cyber-physical systems(CPSs).With the extensive use of open communication mechanisms,the impact of cyber disturbances in public communication networks cannot be diminshed.In this paper,a parameter optimal method for a distributed secondary controller based on the robust control theory and consensus algorithm is presented to enhance the robustness of a secondary control system under data disturbance,parameter perturbation,and time delay.First,a distributed secondary control strategy of microgrids is demonstrated that coordinates frequency and voltage restoration and power sharing.Then,considering the impact of cyber events on the secondary control,a distributed robust controller gain design method is proposed to satisfy the H∞ performance index.The solution of the distributed robust control is transformed into a linear matrix in equation problem and latency margin is simultaneously obtained.Finally,a test microgrid CPS is simulated with and without time delay to investigate the impact of cyber events on system operational states and the effectiveness and robustness of the proposed method.

关键词： Cyber disturbance cyber-physical lsystem distributed control microgrid robust H∞control

MEC-Sim: An Extensible Simulator for Mobile Edge Computing System

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MEC-Sim: An Extensible Simulator for Mobile Edge Computing S...

Distributed Harmonic Power Sharing with Voltage Distortion Suppression in Islanded Microgrids Considering Non-linear Loads

第40届中国控制会议

作者： Zhonghua Li Tao Xie guannan he School of Intelligent Systems Engineering Sun Yat-sen University School of Electronics and Information Technology Sun Yat-sen University

As a new computing paradigm, mobile edge computing（MEC） is able to provide powerful computing resources to serve user-intensive and delay-sensitive applications by configuring mobile edge computing servers at the base stations close to users. To support the simulation and development of MEC, this paper proposes an extensible simulator for MEC system（MECSim）. In the MEC-Sim simulator, simulation configuration module, scheduler module and controller module are designed and the discrete event simulation policy is applied. Three different cases of MEC networks are simulated and evaluated by using three baseline offloading strategies（e.g., local execution, random offloading, and load balance）. Simulation results show that the proposed MEC-Sim is feasible and applicable, which can satisfy the requirements of different MEC networks.

关键词： Mobile Edge Computing System Simulator Discrete Event Simulation Offload Strategy

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 117-128页

作者： guannan Lou Shanlin Li Wei Gu Quan Yang School of Electrical Engineering Southeast UniversityNanjingJiangsu 210096China the Jiangsu Provincial Key Laboratory of Smart Grid Technology and Equipment Southeast University Dongguan Power Supply Bureau of Guangdong Power Grid Company Guangdong 523000China

In contemporary power grids or microgrids,harmonic distortion has emerged as one of the critical power quality issues for utility power grids,which has escalated especially due to the high penetration of power-electronic-converter-interfaced distributed generation(DG).This paper first illustrates the prevalent dispute revolving around the harmonic power sharing and distortion restraint,and subsequently proposes a consensusbased framework that facilitates an accurate sharing of harmonics among multi-DGs connected in parallel,with an effective suppression of the output voltage distortion.Compared with the majority of existing studies addressing the issue of voltage harmonics at the point of common coupling(PCC),our method primarily emphasizes on the output voltage distortion since the power quality requirement for certain local critical loads is often known to be high.With the help of adaptive regulation,the overall distortion produced at the output terminals of DGs can be retained within an acceptable range.The working principle of the proposed control method,which is not only easy to implement but also independent of model parameters,is further described in detail.Employing the small-signal dynamic model,the system stability and robustness are analyzed.The hardware-in-the-loop(HIL)simulations aid in determining the outcome of the proposed strategy in microgrid control.

关键词： Distributed generation droop control harmonic power sharing microgrid voltage distortion mitigation

A Multiscale Model of Mass-Functionally Graded Beam-Fluid System Under Bending and Vibration Responses

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Acta Mechanica Solida Sinica 2024年第2期37卷 327-340页

作者： Lei Zhang Jianping Lin Jiaqing Jiang guannan Wang Department of Civil Engineering Zhejiang University866 Yuhangtang RoadHangzhou310058China Center for Balance Architecture Zhejiang UniversityHangzhou310007China College of Civil Engineering Huaqiao UniversityXiamen361021China Key Laboratory for Intelligent Infrastructure and Monitoring of Fujian Province Huaqiao UniversityXiamen361021China Department of Engineering Mechanics Zhejiang UniversityHangzhou310027China

In this paper,a multiscale model is developed for the mass functionally graded(FG)beam-fluid system to investigate its static and dynamic responses based on 3D printed porous beam free vibration tests,which are determined by two aspects.At the microstructural level,the gradient variation is realized by arbitrary distribution of matrix pores,and the effective moduli under specific distribution are obtained using the micromechanics homogenization theory.In the meantime,at the structural level,the mechanical responses of FG porous beams subjected to mass loading are considered in a static fluid environment.Then,the explicit expressions of local finite-element(FE)expressions corresponding to the static and dynamic responses are given in the appendices.The present results are validated against numerical and experimental results from the literature and mechanical tests of 3D printed structures,with good agreement generally obtained,giving credence to the present model.On this basis,a comprehensive parametric study is carried out,with a particular focus on the effects of boundary conditions,fluid density,and slenderness ratio on the bending and vibration of FG beams with several different gradations.

关键词： 3D printed test Mass functionally graded beam-fluid system Multiscale model Local finite-element expressions Static bending Free vibration