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Equivalence between the internal observability and equation

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 89-97页

作者： LIU Wen-jun tu Zhi-yu School of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjing 210044China

This paper is concerned with a third order in time linear Moore-Gibson-Thompson equation which describes the acoustic velocity potential in ultrasound wave *** by the work of Kaltenbacher,Lasiecka and Marchand(Control Cybernet.2011,40:971-988),we establish an observability inequality of the conservative problem,and then discuss the equivalence between the exponential stabilization of a dissipative system and the internal observational inequality of the corresponding conservative system.

关键词： Moore-Gibson-Thompson equation internal observability exponential stability

Study of Flow and Heat Transfer in an Ejector-Driven Swirl Anti-Icing Chamber

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Fluid Dynamics & Materials Processing 2024年第5期20卷 989-1014页

作者： Yi tu yuan Wu yu Zeng Hunan University of Arts and Sciences Hunan Key Laboratory of Distributed Electric Propulsion Vehicle Control TechnologyChangde415000China Liaoning Provincial Key Laboratory of Aircraft Ice Protection AVIC Aerodynamics Research InstituteShenyang110034China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

The formation of ice on the leading edge of aircraft engines is a serious issue,as it can have catastrophic *** Swirl Anti-Icing(SAI)system,driven by ejection,circulates hot fluid within a 360°annular chamber to heat the engine inlet lip surface and prevent *** study employs a validated Computational Fluid Dynamics(CFD)approach to study the impact of key geometric parameters of this system on flow and heat transfer characteristics within the anti-icing ***,the entropy generation rate and exergy efficiency are analyzed to assess the energy utilization in the *** research findings indicate that,within the considered flow range,reducing the nozzle specific areaφfrom 0.03061 to 0.01083 can enhance the ejection coefficient by over 60.7%.This enhancement increases the air circulating rate,thereby intensifying convective heat transfer within the SAI ***,the reduction inφalso leads to a significant increase in the required bleed air pressure and a higher entropy generation rate,indicating lower exergy *** nozzle angleθnotably affects the distribution of hot and cold spots on the lip surface of the SAI ***θfrom 0°to 20°reduces the maximum temperature difference on the anti-icing chamber surface by 60 K.

关键词： Swirl anti-icing heat transfer exergy efficiency hot and cold spot aircraft engine

A new 4-Ti-added polyoxometalate

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tungsten 2024年第2期6卷 465-471页

作者： Hai-Lou Li Chen lian Guo-yu Yang MOE Key Laboratory of Cluster Science School of Chemistry and Chemical EngineeringBeijing Institute of TechnologyBeijing 102488China

A new inorganic–organic hybrid 4-Ti-added polyoxometalate:[H_(2)N(CH_(3))_(2)]_(2)Na_(3)H_(5)[{Ti(C_(2)O_(4))(H_(2)O)}_(2){Ti(C_(2)O_(4))}_(2)(B-β-SbW_(9)O_(33))_(2)]·22H_(2)O(1)has been successfully made and further characterized by infrared spectroscopy,thermogravimetric analysis,powder X-ray diff raction and single-crystal X-ray diff *** polyoxoanion of 1 exhibits a Krebs-type structure that is constructed from two[B-β-SbW_(9)O_(33)]^(9)−fragments fused together by a belt of four additional Ti atoms decorated by oxalate ***,1 as a heterogeneous catalyst exhibits high activity for Knoevenagel condensation under mild reaction conditions.

关键词： Polyoxometalate Ti-added POM Krebs-type structure Knoevenagel condensation

A coupled Legendre-Laguerre polynomial method with analytical integration for the Rayleigh waves in a quasicrystal layered half-space with an imperfect interface

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1539-1556页

作者： Bo ZHANG Honghang tu Weiqiu CHEN Jiangong yu L.ELMAIMOUNI School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454000Henan ProvinceChina Henan International Joint Laboratory of Advanced Electronic Packaging Materials Precision Forming Henan Polytechnic UniversityJiaozuo 454000Henan ProvinceChina Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Polydisciplinary Faculty of Ouarzazate Ibnou Zohr UniversityOuarzazate 45000Morocco

The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a ***,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when there are significant differences in material ***,a coupled Legendre-Laguerre polynomial method with analytical integration is *** Rayleigh waves in a one-dimensional(1D)hexagonal quasicrystal(QC)layered half-space with an imperfect interface are *** correctness is validated by comparison with available *** computation efficiency is *** dispersion curves of the phase velocity,displacement distributions,and stress distributions are *** effects of the phonon-phason coupling and imperfect interface coefficients on the wave characteristics are *** novel findings reveal that the proposed method is highly efficient for addressing the Rayleigh waves in a QC layered *** can save over 99%of the computation *** method can be expanded to investigate waves in various layered half-spaces,including earth-layered media and surface acoustic wave(SAW)devices.

关键词： coupled Legendre-Laguerre polynomial method analytical integration Rayleigh wave quasicrystal(QC)layered half-space imperfect interface

Suppression of current-induced membrane discharge of bipolar membranes by regulating ion crossover transport

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Journal of Energy Chemistry 2024年第9期96卷 387-395页

作者： Tingting yu Haolan Tao Jingkun Li Cheng lian Honglai Liu State Key Laboratory of Chemical Engineering Shanghai Engineering Research Center of Hierarchical NanomaterialsSchool of Chemical EngineeringEast China University of Science and TechnologyShanghai 200237China School of Chemistry and Molecular Engineering East China University of Science and TechnologyShanghai 200237China

Bipolar membranes(BPMs)exhibit the unique capability to regulate the operating environment of electrochemical system through the water dissociation-combination ***,the industrial utilization of BPMs is limited by instability and serious energy *** current-induced membrane discharge(CIMD)at high-current conditions has a negative influence on the performance of anion-exchange membranes,but the underlying ion transport mechanisms in the BPMs remain ***,the CIMD-coupled Poisson-Nernst-Planck(PNP)equations are used to explore the ion transport mechanisms in the BPMs for both reverse bias and forward bias at neutral and acid-base *** is demonstrated that the CIMD effect in the reverse-bias mode can be suppressed by enhancing the diffusive transport of salt counter-ions(Na^(+)and Cl^(−))into the BPMs,and that in the forward-bias mode with acid-base electrolytes can be suppressed by matching the transport rate of water counter-ions(H_(3)O^(+)and OH^(−)).Suppressing the CIMD can promote the water dissociation in the reverse-bias mode,as well as overcome the plateau of limiting current density and reduce the interfacial blockage of salt co-ions(Cl^(−))in the anion-exchange layer in the forward-bias mode with acid-base *** work highlights the importance of regulating ion crossover transport on improving the performance of BPMs.

关键词： Bipolar membranes Current-induced membrane discharge Salt ion crossover Diffusion-migration-reaction process

Residual subsidence time series model in mountain area caused by underground mining based on GNSS online monitoring

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International Journal of Coal Science & Technology 2024年第2期11卷 173-186页

作者： Xugang lian Lifan Shi Weiyu Kong yu Han Haodi Fan School of Mining Engineering Taiyuan University of TechnologyTaiyuanChina

The residual subsidence caused by underground mining in mountain area has a long subsidence duration time and great potential harm,which seriously threatens the safety of people's production and life in the mining ***,it is necessary to use appropriate monitoring methods and mathematical models to effectively monitor and predict the residual subsidence caused by underground *** with traditional level survey and InSAR(Interferometric Synthetic Aperture Radar)technology,GNSS(Global Navigation Satellite System)online monitoring technology has the advantages of long-term monitoring,high precision and more flexible monitoring *** empirical equation method of residual subsidence in mining subsidence is effectively combined with the rock creep equation,which can not only describe the residual subsidence process from the mechanism,but also predict the residual ***,based on GNSS online monitoring technology,combined with the mining subsidence model of mountain area and adding the correlation coefficient of the compaction degree of caving broken rock and the Kelvin model of rock mechanics,this paper constructs the residual subsidence time series model of arbitrary point on the ground in mountain *** the example,the predicted results of the model in the inversion parameter phase and the dynamic prediction phase are compared with the measured data *** results show that the model can carry out effective numerical calculation according to the GNSS monitoring data of any point on the ground,and the model prediction effect is good,which provides a new method for the prediction of residual subsidence in mountain mining.

关键词： Underground mining in mountain area Residual subsidence GNSS online monitoring Mathematical model Subsidence prediction

Neural Dynamics for Cooperative Motion Control of Omnidirectional Mobile Manipulators in the Presence of Noises: A Distributed Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1605-1620页

作者： yufeng lian Xingtian Xiao Jiliang Zhang Long Jin Junzhi yu Zhongbo Sun the Department of Control Engineering Changchun University of TechnologyChangchun 130012China IEEE the College of Information Science and Engineering Northeastern UniversityShenyang 110819 the National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China the School of Information Science and Engineering Lanzhou UniversityLanzhou 730000China the State Key Laboratory for turbulence and Complex Systems Department of Advanced Manufacturing and RoboticsCollege of EngineeringPeking UniversityBeijing 100871China

This paper presents a distributed scheme with limited communications, aiming to achieve cooperative motion control for multiple omnidirectional mobile manipulators(MOMMs).The proposed scheme extends the existing single-agent motion control to cater to scenarios involving the cooperative operation of MOMMs. Specifically, squeeze-free cooperative load transportation is achieved for the end-effectors of MOMMs by incorporating cooperative repetitive motion planning(CRMP), while guiding each individual to desired poses. Then, the distributed scheme is formulated as a time-varying quadratic programming(QP) and solved online utilizing a noise-tolerant zeroing neural network(NTZNN). Theoretical analysis shows that the NTZNN model converges globally to the optimal solution of QP in the presence of noise. Finally, the effectiveness of the control design is demonstrated by numerical simulations and physical platform experiments.

关键词： Cooperative motion control noise-tolerant zeroing neural network(NTZNN) omnidirectional mobile manipulator(OMM) repetitive motion planning

Molecularly imprinted sensor based on carboxylated carbon nanotubes/Keggin-type polyoxometalates nanocomposite for the detection of furazolidone

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tungsten 2024年第2期6卷 394-409页

作者： yu-Lan Huang Bing Zhang yu-lian Li Li Wang Le Dong Jian Li College of Ocean Food and Biological Engineering Jimei UniversityXiamen 361021China College of Oceanology and Food Science Quanzhou Normal UniversityQuanzhou 362000China

Due to its properties of mutagenic,teratogenic,and carcinogenic,the detection of furazolidone(FZD)in aquaculture is of great importance for food safety and human *** this study,molecularly imprinted fi lms modifi ed with carboxylated multi-walled carbon nanotube-phosphomolybdic acid composite were used to fabricate an electrochemical sensor for the determination of *** nanocomposites were characterized using infrared spectroscopy,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and X-ray diff *** electrochemical characteristics of the modifi ed electrodes were examined using electrochemical impedance spectroscopy,cyclic voltammetry,and diff erential pulse *** sensor exhibited exceptional catalytic *** calibration curves were acquired in the concentration range of 6 nmol·L^(−1)to 0.6μmol·L^(−1),with a limit of detection of 3.38 nmol·L^(−1).Additionally,the sensor proved successful in recognizing FZD in shrimp samples with satisfactory recoveries and *** method provides a strategy to construct a molecularly imprinted electrochemical sensing platform using nanomaterials,which has great promise in the field of food safety.

关键词： Phosphomolybdate Furazolidone Polyoxometalates Carboxylated multi-walled carbon nanotube Molecularly imprinted polymers Electrochemical sensor

Microstructure,wear and friction behavior of CoCrAITaY-xCNTs composite coatings deposited by laser-induction hybrid cladding

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Rare Metals 2024年第4期43卷 1815-1827页

作者： Sheng-Feng Zhou yu Long Yan-liang Yi Cheng Deng lian-Xi Hu Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou510632China Wuhan National Laboratory for Optoelectronics(WNLO) Huazhong University of Science and TechnologyWuhan430074China MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured MaterialsGuangxi UniversityNanning530004China School of Mechatronics Engineering Guangdong Polytechnic Normal UniversityGuangzhou510635China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China

To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes(CNTs)chemically reacted with Ta to form reinforcement phase(TaC),while the other CNTs were retained as lubrication ***,the CoCrAlYTa-xCNTs(x=0,1,2,and 4;wt%)composite coatings were prepared by laserinduction hybrid cladding(LIHC),and the microstructure and wear resistance of coatings were systematically *** show that the coatings are mainly composed of TaC,y-(Co,Cr)andβ-(Co,Cr)*** the CNTs content increases from 0 wt%to 4 wt%,the volume fraction of TaC increases from 13.11 vol%to 16.12 vol%.Meanwhile,the nano-hardness ofγ-(Co,Cr)andβ-(Co,Cr)Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,*** a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4×10^(-3)to 6.1×10^(-3)mg·m^(-1),and the average friction coefficient decreases from 0.55 to *** good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.

关键词： Carbon nanotube MCrAlY coating Friction and wear performance Laser-induction hybrid cladding