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Comparative analysis between single-train passing and double-train intersection in a tunnel

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2024年第5期25卷 429-442页

作者： Jianming DU Qian FANG Xuan ZHANG Hualao WANG Bridge and Tunnel research center Research Institute of Highway Ministry of TransportBeijing 100088China Tunnel and Underground engineering research center of Ministry of Education Beijing Jiaotong UniversityBeijing 00044China

Aerodynamic pressure significantly impacts the scientific evaluation of tunnel service *** aerodynamic pressure of two trains running in a double-track tunnel is considerably more complicated than that of a single *** used the numerical method to investigate the difference in aerodynamic pressure between a single train and two trains running in a double-track ***,the numerical method was verified by comparing the results of numerical simulation and on-site ***,the characteristics of aerodynamic pressure were ***,the influence of various train-tunnel factors on the characteristics of aerodynamic pressure was *** results show that the aerodynamic pressure variation can be divided into stage I:irregular pressure fluctuations before the train tail leaves the tunnel exit,and stage II:periodic pressure declines after the train tail leaves the tunnel *** addition,the aerodynamic pressure simultaneously jumps positively or drops negatively for a single train or two trains running in double-track tunnel *** pressure amplitude in the two-train case is higher than that for a single *** maximum positive peak pressure difference(P_(STP))and maximum negative peak pressure difference(P_(STN))increase as train speed rises to the power from 2.256 to 2.930 in stage *** P_(STP) and P_(STN) first increase and then decrease with the increase of tunnel length in stage *** P_(STP) and P_(STN) increase as the blockage ratio rises to the power from 2.032 to 2.798 in stages I and II.

关键词： Railway tunnel Aerodynamic effect Pressure characteristic Train speed Tunnel length Blockage ratio

Optimal Stochastic Scheduling Strategy of Multi-vector Energy Complex Integrated with Full-blown Power-to-biomethane Model

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Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 863-873页

作者： Guanwei Zeng Chengxi Liu Minfang Liao Yongjian Luo Xuzhu Dong hubei engineering and Technology research center for AC/DC Intelligent Distribution Network WuhanChina the School of Electrical engineering and Automation Wuhan UniversityWuhanChina

We propose an optimal stochastic scheduling strategy for a multi-vector energy complex(MEC),considering a fullblown model of the power-to-biomethane(Pt M)*** conventional optimization that uses a simple efficiency coefficient to coarsely model energy conversion between electricity and biomethane,a detailed Pt M model is introduced to emphasize the reactor kinetics and chemical equilibria of *** model crystallizes the interactions between the Pt M process and MEC flexibility,allowing to adjust the operating condition of the methanation reactor for optimal MEC operation in stochastic *** optimization and flowsheet design of the Pt M process increase the average selectivity of methane(i.e.,ratio between net biomethane production and hydrogen consumption)up to 83.7%in the proposed synthesis *** results can provide information and predictions to operators about the optimal operating conditions of a Pt M unit while improving the MEC flexibility.

关键词： Multi-vector energy complex optimal stochastic scheduling power-to-biomethane unit process synthesis natural gas

The Influence of Chemical Admixtures on the Fluidity,Viscosity and Rheological Properties of Ultra-High Performance Concrete

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Fluid Dynamics & Materials Processing 2024年第10期20卷 2163-2181页

作者： Jin Yang Hailong Zhao Jingyi Zeng Ying Su Mengdi Zhu Xingyang He School of Civil engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China Building Waterproof engineering and Technology research center of hubei Province Hubei University of TechnologyWuhan430068China

To achieve higher strength and better durability,ultra-high performance concrete(UHPC)typically employs a relatively small water-binder ***,this generally leads to an undesired increase in the paste *** this study,the effects of liquid and powder polycarboxylate superplasticizers(PCE)on UHPC are compared and critically ***,the following influential factors are considered:air-entraining agents(AE),slump retaining agents(SA),and defoaming agents(DF)and the resulting flow characteristics,mechanical properties,and hydration properties are evaluated assuming UHPC containing 8‰powder PCE(PCE-based UHPC).It is found that the spread diameter of powder PCE is 5%higher than that of liquid *** the chemical admixtures studied,AEs have the best effect on improving UHPC workability,while DFs have the worst *** the addition of AE and SA is 1.25‰and 14.7%of PCE,paste viscosity reduces by 35%and 19%,respectively compared to the paste with only 8‰PCE.A low AE dosage(1.25‰)decreases compressive strength by 4.1%,while SA(8.1%)increases UHPC compressive strength by 9.1%.Both AE and SA significantly delay the UHPC hydration process,reducing the hydration heat release peaks by 76%and 27%,respectively.

关键词： Ultra-high performance concrete polycarboxylate superplasticizer air-entraining agent slump retaining agent rheological properties

Synergism of solar-driven interfacial evaporation and photo-Fenton Cr(Ⅵ) reduction by sustainable Bi-MOF-based evaporator from waste polyester

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Journal of Energy Chemistry 2024年第7期94卷 527-540页

作者： Zifen Fan Jie Liu Huajian Liu Lijie Liu Yan She Xueying Wen Huiyue Wang Guixin Hu Ran Niu Jiang Gong Key Laboratory of Material Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Material Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSemiconductor Chemistry CenterSchool of Chemistry and Chemical EngineeringHuazhong University of Science andTechnologyWuhan430074HubeiChina

The integration of interfacial solar steam generation and photocatalytic degradation technology has pro-vided a promising platform to simultaneously produce freshwater and degrade ***,con-structing low-cost,multi-functional evaporators for treating Cr(Ⅵ)-polluted water remains challenging,and the synergistic mechanism on Cr(Ⅵ)reduction is ***,we propose the combined strategy of ball milling and solution mixing for the sustainable production of Bi-MOF microrod from waste poly(ethylene terephthalate),and construct Bi-MOF-based solar evaporators for simultaneous photo-Fenton Cr(Ⅵ)reduction and freshwater ***,the evaporator comprised of Bi-MOF microrod and graphene nanosheet possesses high light absorption,efficient photothermal conversion,and good hydro-philic *** to the advantages,the hybrid evaporator exhibits the evaporation rate of 2.16 kg m^(-2) h^(-1) and evaporation efficiency of 87.5%under 1 kW m^(-2) of *** integrating with photo-Fenton reaction,the Cr(Ⅵ)reduction efficiency is 91.3%,along with the reaction kinetics of 0.0548 min^(-1),surpassing many advanced *** the outdoor freshwater production and Cr(Ⅵ)reduction,the daily accumulative water yield is 5.17 kg m^(-2) h^(-1),and the Cr(Ⅵ)reduction efficiency is 99.9%.Furthermore,we prove that the localization effect derived from the interfacial solar-driven evap-oration enhances H_(2)O_(2) activation for the photo-Fenton reduction of Cr(Ⅵ).Based on the result of density functional theory,Bi-MOF microrod provides rich active centers for H_(2)O_(2) activation to produce active sites such as e-or-O_(2).This study not only proposes a new strategy to construct multi-functional solar evaporators for freshwater production and catalytic reduction of pollutants,but also advances the chem-ical upcycling of waste polyesters.

关键词： Interfacial solar steam generation Cr(VI)reduction Photo-Fenton reaction Metal-organic framework Waste plastic upcycling

Online interactive identification method based on ESO disturbance estimation for motion model of double propeller propulsion unmanned surface vehicle

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Control Theory and Technology 2024年第2期22卷 292-314页

作者： Yong Xiong Xianfei Wang Siwen Zhou School of Navigation Wuhan University of TechnologyWuhan430063HubeiChina National engineering research center for Water Transport Safety Wuhan430063HubeiChina hubei Inland Technology Key Laboratory Wuhan430063HubeiChina

In this paper, the online parameter identification problem of the mathematical model of an unmanned surface vehicle (USV) considering the characteristics of the actuator is studied. A data-driven mathematical model of motion is very meaningful to realize trajectory prediction and adaptive motion control of the USV. An interactive identification algorithm (ESO–MILS, extended state observer–multi-innovation least squares) based on ESO is proposed. The robustness of online identification is improved by expanding the state observer to estimate the current disturbance without making artificial assumptions. Specifically, the three-degree-of-freedom dynamic equation of the double propeller propulsion USV is constructed. A linear model for online identification is derived by parameterization. Based on the least square criterion function, it is proved that the interactive identification method with disturbance estimation can improve the identification accuracy from the perspective of mathematical expectation. The extended state observer is designed to estimate the unknown disturbance in the model. The online interactive update improves the disturbance immunity of the identification algorithm. Finally, the effectiveness of the interactive identification algorithm is verified by simulation experiment and real ship experiment.

关键词： Identification of parameters Ship motion model Extended state observer Multinomial innovation least squares Interactive identification

Robustα-Fe_(2)O_(3)/Epoxy Resin Superhydrophobic Coatings for Anti-icing Property

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 621-626页

作者：乔燕明 TAO Xuan LI Lei 阮敏鲁礼林 College of Chemistry and Chemical engineering Wuhan University of Science and TechnologyWuhan 430081China hubei Key Laboratory of Mine Environmental Pollution Control&Remediation and hubei engineering research center for Collaborative Technology of Advanced Material Manufacturing and Solid Waste Recycling Hubei Polytechnic UniversityHuangshi 435003China

α-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating was prepared withα-Fe_(2)O_(3) nanoparticles and epoxy resin by spin coating *** coating without epoxy resin has higher contact angle(CA)and lower ice adhesion strength(IAS),but the mechanical properties are ***α-Fe_(2)O_(3)/epoxy resin composite superhydrophobic coating exhibits good mechanical *** addition,compared with the bare aluminum substrate,the Ecorr of the composite coating is positive and the Jcorr is *** inhibition efficiency of the composite coating is as high as 99.98%in 3.5 wt%NaCl *** difference in the microstructure caused by the two preparation methods leads to the changes in mechanical properties and corrosion resistance of composite superhydrophobic coating.

关键词： superhydrophobic anti-corrosion anti-icing robust

Power Flow Analytical Solutions and Multi-dimensional Voltage Stability Boundaries Based on Multivariate Quotient-difference Method

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1168-1178页

作者： Chengxi Liu Qiupin Lai School of Electrical engineering and Automation Wuhan UniversityWuhan 430072China hubei engineering and Technology research center for AC/DC Intelligent Distribution Network Wuhan 430072China IEEE

This paper proposes a novel Multivariate Quotient-Difference(MQD)method to obtain the approximate analytical solution for AC power flow ***,in the online environment,the power flow solutions covering different operating conditions can be directly obtained by plugging values into multiple symbolic variables,such that the power injections and consumptions of selected buses or areas can be independently *** method first derives a power flow solution through a Multivariate Power Series(MPS).Next,the MQD method is applied to transform the obtained MPS to a Multivariate Pad´e Approximants(MPA)to expand the Radius of Convergence(ROC),so that the accuracy of the derived analytical solution can be significantly *** addition,the hypersurface of the voltage stability boundary can be identified by an analytical formula obtained from the coefficients of *** direct method for power flow solutions and voltage stability boundaries is fast for many online applications,since such analytical solutions can be derived offline and evaluated online by only plugging values into the symbolic variables according to the actual operating *** proposed method is validated in detail on New England 39-bus and IEEE 118-bus systems with independent load variations in multi-regions.

关键词： Analytical power flow solution multivariate power series multivariate Padéapproximants multivariate quotient-difference multi-dimensional voltage stability boundary

A Parallel-type Load Damping Factor Controller for Frequency Regulation in Power Systems with High Penetration of Renewable Energy Sources

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1019-1030页

作者： Zhe Zhang Siyang Liao Yuanzhang Sun Jian Xu Deping Ke Bo Wang Rui Chen Yibo Jiang hubei engineering and Technology research center for AC/DC Intelligent Distribution Network School of Electrical Engineering and AutomationWuhan UniversityWuhan 430072China State Grid hubei Electric Power Company Limited Economic research Institute Wuhan 430074China State Grid(Suzhou)City&Energy research Institute Company Limited Suzhou 215000China

Renewable energy sources(RESs)are rapidly devel-oping and their substitution for traditional power generation poses significant challenges to the frequency regulation in pow-er *** load damping factor D characterizes the active power of load that changes with power system frequency,which is an important factor influencing the frequency ***-ever,the value of D is small,resulting in the limitation in fre-quency regulation of the power *** paper proposes a parallel-type load damping factor controller to enhance load damping factor by utilizing static var generators(SVGs)in ***,it discusses the configuration method for the relevant parameters of the controller,evaluates its frequen-cy regulation capability,investigates the impact of large-scale application of the controller on static and dynamic loads,and conducts a comprehensive evaluation of the impact of the damp-ing factor control process on the voltage stability of the main *** large-scale application of the proposed controller can significantly improve the frequency regulation capability,and al-most have no influence on the working status of the *** can also significantly improve the dynamic performance of system *** proposed controller can provide technical sup-port for the frequency regulation of new power systems with high proportion of RESs.

关键词： Load damping factor parallel-type load damping factor controller power system frequency regulation highproportion renewable energy system

The New Methods for Characterization of Molecular Weight of Supramolecular Polymers

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Chinese Journal of Polymer Science 2024年第10期42卷 1403-1413,I0006页

作者： Hui Liu Rui Hu Zi-Qing Hu Xiao-Fan Ji Key Laboratory of Materials Chemistry for Energy Conversion and Storage Ministry of EducationHubei Key Laboratory of Materials Chemistry and Service FailureHubei Engineering Research Center for Biomaterials and Medical Protective MaterialsSchool of Chemistry and Chemical EngineeringHuazhong University of Science and TechnologyWuhan430074China

Supramolecular polymers,as a type of dynamic polymers,are subordinate to the interdisciplinary field of polymer chemistry and supramolecular chemistry,whose development has greatly promoted the prosperity of new ***,molecular weight is one of the most important parameters of supramolecular polymers,which affects the physical/chemical properties and processing applications of *** new methods for characterizing the molecular weight of supramolecular polymers is crucial for advancing the development of supramolecular *** this review,we elaborate and summarize three strategies for characterizing the molecular weight of supramolecular polymers that recently reported by our research group according to the characteristics of supramolecular polymers,including(1)the molecular weight distinction corresponding to variable fluorescence colors,(2)matching different molecular weights with different fluorescence lifetime,(3)transforming supramolecular polymers into mechanically interlocked polymers or covalent ***,we also discuss the limitations of current methods for characterizing supramolecular *** hope that this review can promote the development of supramolecular polymers and significantly inspire to exploit new methods to characterizing molecular weight of supramolecular polymers.

关键词： Supramolecular polymers Molecular weight Self-assembly Mechanically interlocked polymers Dynamic polymers