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Vibration suppression for rotating space slender flexible structures based on novel deformation description and NNSMC controller with hyperbolic tangent function

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Chinese Journal of Aeronautics 2024年第10期37卷 339-364页

作者： Dongyang SHANG Xiaopeng LI Men YIN Sainan ZHOU School of Mechanical Engineering and Automation Northeastern UniversityShenyang 110819China shenzhen institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China

Rotating Space Slender Flexible Structures(RSSFS)are extensively utilized in space operations because of their light weight,mobility,and low energy *** realize the accurate space operation of the RSSFS,it is necessary to establish a precise mechanical model and develop a control algorithm with high ***,with the application of traditional control strategies,the RSSFS often suffers from the chattering phenomenon,which will aggravate structure *** this paper,novel deformation description is put forward to balance modeling accuracy and computational efficiency of the RSSFS,which is better appropriate for real-time ***,the Neural Network Sliding Mode Control(NNSMC)strategy modified by the hyperbolic tangent(tanh)function is put forward to compensate for modeling errors and reduce the chattering phenomenon,thereby improving the trajectory tracking accuracy of the ***,a mathematical model for the RSSFS is developed according to the novel deformation description and the vibration theory of flexible *** of the deformation accuracy between different models proves that the novel modeling method proposed has high modeling ***,the universal approximation property of the Radial Basis Function(RBF)neural network is put forward to determine and compensate for modeling errors,which consist of higher-order modes and the uncertainties of external *** addition,the tanh function is proposed as the reaching law in the conventional NNSMC strategy to suppress driving torque *** control law of modified NNSMC strategy and the adaptive law of weight coefficients are developed according to the Lyapunov theorem to guarantee the RSSFS ***,the simulation and physical experimental tests of the RSSFS with different control strategies are *** results show that the control law according to the novel deformation description and the modified NNSMC strategy can obta

关键词： Space slender flexible structure Novel deformation description RBF neural network Vibration suppression Hyperbolic tangent function

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Metal-organic framework-based single-atom electro-/ photocatalysts: Synthesis, energy applications, and opportunities

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Carbon Energy 2024年第1期6卷 1-43页

作者： Munir Ahmad Jiahui Chen Jianwen Liu Yan Zhang Zhongxin Song Shahzad Afzal Waseem Raza Liaqat Zeb Andleeb Mehmood Arshad Hussain Jiujun Zhang Xian-Zhu Fu Jing-Li Luo shenzhen Key Laboratory of Energy Electrocatalytic Materials Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhenGuangdongChina College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhenGuangdongChina College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhenGuangdongChina Department of Environmental Engineering China Jiliang UniversityHangzhouZhejiangChina institute for Advanced Study Shenzhen UniversityShenzhenGuangdongChina School of Bioengineering Dalian University of TechnologyDalianLiaoningChina College of Materials Science and Engineering Fuzhou UniversityFuzhouFujianChina institute for Sustainable Energy Shanghai UniversityShanghaiChina

Single-atom catalysts(SACs)have gained substantial attention because of their exceptional catalytic ***,the high surface energy limits their synthesis,thus creating significant challenges for further *** the last few years,metal–organic frameworks(MOFs)have received significant consideration as ideal candidates for synthesizing SACs due to their tailorable chemistry,tunable morphologies,high porosity,and chemical/thermal *** this perspective,this review thoroughly summarizes the previously reported methods and possible future approaches for constructing MOF-based(MOF-derived-supported and MOF-supported)***,MOF-based SAC's identification techniques are briefly assessed to understand their coordination environments,local electronic structures,spatial distributions,and catalytic/electrochemical reaction *** review systematically highlights several photocatalytic and electrocatalytic applications of MOF-based SACs for energy conversion and storage,including hydrogen evolution reactions,oxygen evolution reactions,O_(2)/CO_(2)/N_(2) reduction reactions,fuel cells,and rechargeable *** light is also shed on the future development of this highly exciting field by highlighting the advantages and limitations of MOF-based SACs.

关键词： carbon energy generation MOF-derived-supported MOF-supported single atoms

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Effects of dynamical spanwise retraction and stretch on flapping-wing forward flights

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Chinese Journal of Aeronautics 2024年第4期37卷 181-202页

作者： Kang LIU Bifeng SONG Ang CHEN Zhihe WANG Dong XUE Wenqing YANG School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Intelligent Aircraft Research Center Chengdu Technological UniversityChengdu 610031China Research&Development institute of Northwestern Polytechnical University in shenzhen Shenzhen 518057China Harbin institute of Technology Shenzhen 518055China

Birds and bats retract and stretch their wings dynamically during each flap in level flights, implying intriguing mechanisms for the aerodynamic performance improvement of flapping wings. A numerical investigation into the aerodynamic effects of such bio-inspired concept in forward flights has been performed based on a three-dimensional wing in plunging motion and a twosection wing in flapping motion. The currently considered Reynolds number and Strouhal number are Re=1.5×10^(5) and St=0.3, respectively. During the research, the mean angle of attack is varied in relatively wide ranges to achieve lift-thrust interconversion for the wings. The conclusive results show that dynamical spanwise retraction and stretch has induced three absolutely desirable scenarios for the oscillating wings in forward flights, namely producing more lift and consuming less power for a given thrust generation, producing more thrust and consuming less power for a given lift generation, and producing more lift and more thrust while consuming less power. Furthermore,the morphing wings have alleviated periodical aerodynamic load fluctuations compared with the non-morphing baseline. The mechanism of the aerodynamic effects of the bionic morphing mode is analyzed with the aid of field visualization. The current article is the first to reveal the absolute advantages of the bionic spanwise morphing. Hopefully, it may help comprehend the behaviors of natural fliers and provide inspirations for performance enhancement of micro artificial flappingwing vehicles.

关键词： Flapping wing Morphing wing Bionic Aerodynamics Vortex Flight

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Hydrophilic polyanionic hydrogel electrolyte for anti-freezing and bending resistant zinc-ion hybrid supercapacitors

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Journal of Materiomics 2024年第6期10卷 1299-1307页

作者： Xuejuan Wan Hangqi Song Zejia Zhao Zuocai Zhang Jingwei Wang Junye Cheng shenzhen Key Laboratory of Polymer Science and Technology Guangdong Research Center for Interfacial Engineering of Functional MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen518060China Department of Materials Science Shenzhen MSU-BIT UniversityShenzhen517182China institute of Semiconductor Manufacturing Research College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen518060China

Zinc-ion hybrid supercapacitors(ZHSCs)have been widely considered as promising candidates for flexible electrochemical energy storage *** key challenge is to develop hydrogel electrolytes with high hydrophilicity,anti-freezing,bending resistance,and stable interface with *** study reported a hydrogel electrolyte system that can meet the above functions,in which the zincophilic and negatively charged SO3−,migratable Na+,abundant hydrophilic functional groups,gum xanthan,and porous architecture could effectively promote the electrochemical performance of *** with such hydrogel electrolytes not only exhibited good low-temperature performance but also showed excellent bending resistance ability.A high specific capacitance could be kept after a long air-working lifespan over 10,000 cycles under a wide operation voltage of 1.85 V at−10℃.Furthermore,flexible ZHSCs could maintain the capacitance retention of 93.18%even after continuous 500 bends at an angle of 180°.The designed hydrogel electrolytes could be also used for other electrochemical energy storage devices with anti-freezing and bending resistance by changing electrolyte salt.

关键词： Zn-ion hybrid supercapacitors Polyanionic Anti-freezing Bending resistance Porous architecture

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Numerical Simulation of Asphaltene Precipitation and Deposition during Natural Gas and CO_(2) Injection

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Fluid Dynamics & Materials Processing 2024年第2期20卷 275-292页

作者： Shasha Feng Yi Liao Weixin Liu Jianwen Dai Mingying Xie Li Li Nanhai East Petroleum Research institute Shenzhen Branch of CNOOC Ltd.Shenzhen518000China

Asphaltene deposition is a signiﬁcant problem during gas injection processes,as it can block the porous medium,the wellbore,and the involved facilities,signiﬁcantly impacting reservoir productivity and ultimate oil *** a few studies have investigated the numerical modeling of this potential effect in porous *** study focuses on asphaltene deposition due to natural gas and CO_(2) *** of the effect of gas injection on asphaltene deposition behavior have been made using a 3D numerical simulation *** results indicate that the injection of natural gas exacerbates asphaltene deposition,leading to a signiﬁcant reduction in permeability near the injection well and throughout the *** reduction in permeability strongly affects the ability of gas toﬂow through the reservoir,resulting in an improvement of the displacement *** displacement efﬁ-ciency of the injection gas process increases by up to 1.40%when gas is injected at 5500 psi,compared to the scenario where the asphaltene model is not ***_(2) injection leads to a miscible process with crude oil,extracting light and intermediate components,which intensiﬁes asphaltene precipitation and increases the viscosity of the remaining crude oil,ultimately reducing the recovery rate.

关键词： Reservoir simulation asphaltenes deposition natural gas injection CO_(2)injection

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Efficient cutting path planning for a non-spherical tool based on an iso-scallop height distance field

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Chinese Journal of Aeronautics 2024年第7期37卷 496-510页

作者： Jiancheng HAO Dong HE Zhaoyu LI Pengcheng HU Yuanzhi CHEN Kai TANG Department of Mechanical and Aerospace Engineering Hong Kong University of Science and TechnologyHong Kong 999077China The Hong Kong University of Science and Technology(Guangzhou) Smart Manufacturing ThrustNanshaGuangzhou 511400China HKUST shenzhen-Hong Kong Collaborative Innovation Research institute Shenzhen 518057China HKUST shenzhen Research institute Shenzhen 518057China

Iso-scallop height machining means,when machining a freeform surface,the scallop height between any two neighboring tool paths on the surface will be a constant(i.e.,the given threshold),which is preferable among various freeform surface machining strategies due to its high machining efficiency as well as better machine tool’s ***,all the existing iso-scallop height path planning methods pertain to only the ball-end or flat-end types of *** recent years,the non-spherical cutting tool has become more and more popular,especially for five-axis machining of complex freeform surfaces,majorly owing to its non-constant curvature which can be utilized to adaptively fit the tool to the surface to both avoid the local gouging and enlarge the cutting ***,there have been no reported works on iso-scallop height five-axis tool path generation for a non-spherical tool,and,in this paper,we present ***,we first define and construct two fields on the surface to be machined-the collision-free tool orientation field(vector)and the iso-scallop height distance field(scalar).The iso-lines of the scalar field and their associated tool orientation field vectors then naturally serve as potential iso-scallop height five-axis tool paths,and we present a propagation-based algorithm to construct the desired tool path from the *** computer simulation and physical cutting experiments confirm that everywhere on the surface,except maybe near the saddle curves of the scalar filed,the scallop height is exactly the given *** adding the saddle curves as extra tool paths,the final machined surface then is assured of the required scallop height requirement.

关键词： Freeform surface machining Iso-scallop tool path Customized tool Five-axis tool path Computer aided manufacturing

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Mn-based MXene with high lithium-ion storage capacity

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Nano Research 2024年第5期17卷 4181-4191页

作者： Yanyan Wu Dongqing Liu Xiaonan Wang Usman Ghani Muhammad Asim Mushtaq Jinfeng Yang Huarui Sun Panagiotis Tsiakaras Xingke Cai School of Science and Ministry of Industry and Information Technology Key Laboratory of Micro-Nano Optoelectronic Information System Harbin Institute of Technology ShenzhenShenzhen 5180552 China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China institute for Advanced Study Shenzhen UniversityShenzhen 518060China College of Mechatronics and Control Engineering Shenzhen UniversityShenzhen 518060China Laboratory of Alternative Energy Conversion Systems Department of Mechanical EngineeringSchool of EngineeringUniversity of ThessalyPedion Areos 38834Greece

3d-transition metal(Fe,Co,Ni,and Mn)-based MXene materials have been predicted to demonstrate exceptional electrochemical performance because of their good electrical conductivity and the presence of metallic atoms with multiple charge ***,until now,there have been no reports on MXenes based on Fe,Co,Ni,and Mn,due to the lack of 3d-metal-layered ***,we successfully synthesized the first 3d-transition metal-based MXenes,Mn_(2)CT_(x) by exfoliating a layered precursor derived from the anti-perovskite bulk *** as-prepared Mn_(2)CT_(x) MXene nanosheets were employed as anode materials in lithium-ion batteries,which exhibited stable storage capacity of 764.7 mAh·g^(-1) at 0.5 C,placing its storage capacities at an upper-middle level compared with other reported MXene materials as well as other Mn-based anode ***,this study opens a new avenue for MXene research by synthesizing 3d-transition metal-based MXenes for electrochemical applications.

关键词： Mn_(3)GaC Mn_(2)CT_(x) MXenes lithium-ion battery anode materials negative fading capacity

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Discriminatively Constrained Semi-Supervised Multi-View Nonnegative Matrix Factorization with Graph Regularization

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Big Data Mining and Analytics 2024年第1期7卷 55-74页

作者： Guosheng Cui Ye Li Jianzhong Li Jianping Fan shenzhen institute of Advanced Technology Chinese Academy of SciencesShenzhen 518055China Joint Engineering Research Center for Health Big Data Intelligent Analysis Technology Shenzhen 518055China University of Chinese Academy of Sciences Beijing 100049China School of Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

Nonnegative Matrix Factorization(NMF)is one of the most popular feature learning technologies in the field of machine learning and pattern *** has been widely used and studied in the multi-view clustering tasks because of its *** study proposes a general semi-supervised multi-view nonnegative matrix factorization *** algorithm incorporates discriminative and geometric information on data to learn a better-fused representation,and adopts a feature normalizing strategy to align the different *** specific implementations of this algorithm are developed to validate the effectiveness of the proposed framework:Graph regularization based Discriminatively Constrained Multi-View Nonnegative Matrix Factorization(GDCMVNMF)and Extended Multi-View Constrained Nonnegative Matrix Factorization(ExMVCNMF).The intrinsic connection between these two specific implementations is discussed,and the optimization based on multiply update rules is *** on six datasets show that the effectiveness of GDCMVNMF and ExMVCNMF outperforms several representative unsupervised and semi-supervised multi-view NMF approaches.

关键词： multi-view semi-supervised clustering discriminative information geometric information feature normalizing strategy

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Total Synthesis of Laurane and Guaiane Sesquiterpenoids via Oxidative Nazarov Reaction

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Chinese Journal of Chemistry 2024年第11期42卷 1267-1274页

作者： Yuye Chen Wenqing Chen Zhiting Zhang Jing Xu shenzhen Grubbs institute and Department of Chemistry and Guangming Advanced Research institute and Guangdong Provincial Key Laboratory of Catalysis and shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis Southern University of Science and TechnologyShenzhenGuangdong518055 China

As one of the most common structural motifs in natural products,cyclopentenones usually can be fabricated by Nazarov cyclization using divinyl ketones or functionalized tertiary divinyl carbinols(TDCs)as ***,straightforward method for transforming unfunctionalized TDCs to their corresponding cyclopentenones is currently ***,we wish to report the total syntheses of four structurally distinct terpenoids,namely laurane-type marine sesquiterpenoids isolaurene,debromoaplysin and aplysin,and guaiane sesquiterpenoid guaiadienone A,all using a novel synthetic method,named oxidative Nazarov cyclization,as the key *** work demonstrated our robust method is suitable for synthesizing various highly substituted cyclopentenones.

关键词： Total synthesis Synthetic methods Sesquiterpenoids Oxidative Nazarov reaction Electrocyclization Oxoammonium salt Pericyclic reaction Annulation

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Interlayer exciton dynamics of transition metal dichalcogenide heterostructures under electric fields

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Nano Research 2024年第5期17卷 4555-4572页

作者： Jian Tang Yue Zheng Ke Jiang Qi You Zhentian Yin Zihao Xie Henan Li Cheng Han Xiaoxian Zhang Yumeng Shi International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060China College of Electronics and Information Engineering Shenzhen UniversityShenzhen 518060China Key Laboratory of Luminescence and Optical Information Ministry of EducationInstitute of Optoelectronic TechnologyBeijing Jiaotong UniversityBeijing 100044China

Stacking single layers of atoms on top of each other provides a fundamental way to achieve novel material systems and engineer their physical properties,which offers opportunities for exploring fundamental physics and realizing next-generation optoelectronic *** the two-dimensional(2D)-stacked systems,transition metal dichalcogenide(TMDC)heterostructures are particularly attractive because they host tightly-bonded interlayer excitons which possess various novel and appealing *** interlayer excitons have drawn significant research attention and hold high potential for the application in unique optoelectronic devices,such as polarization-and wavelength-tunable single photon emitters,valley Hall transistors,and possible high-temperature *** development of these devices requires a comprehensive understanding of the fundamental properties of these interlayer excitons and the impact of electric fields on their *** this review,we summarize the recent advances on the understanding of interlayer exciton dynamics under electric fields in TMDC *** put emphasis on the electrical modulation of interlayer excitons’emission,the valley Hall transport of charge carriers after the separation of interlayer excitons by an electric field,and the correlation physics of interlayer excitons and charges under electrical doping and *** and perspectives are finally discussed for the application of TMDC heterostructures in future optoelectronics.

关键词： interlayer exciton transition metal dichalcogenide(TMDC)heterostructures circular polarization valley Hall effect strong coupling

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