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Comparisons of Wave Force Model Effects on the Structural Responses and Fatigue Loads of a Semi-Submersible Floating Wind Turbine

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Journal of ocean University of China 2024年第1期23卷 69-79页

作者： han Yanqing LE Conghuan ZhanG Puyang XU Shengnan State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China School of Hydraulic Engineering Ludong UniversityYantai 264025China School of Civil Engineering Tianjin UniversityTianjin 300072China Shandong Marine Aerospace Equipment Technological Innovation Center Yantai 264004China

The selection of wave force models will significantly impact the structural responses of floating wind *** this study,comparisons of wave force model effects on the structural responses and fatigue loads of a semi-submersible floating wind turbine(SFWT)were *** were performed by employing the Morison equation(me)with linear or second-order wave kinematics and potential flow theory(PFT)with first-or second-order wave forces.A comparison of regular waves,irregular waves,and coupled wind/waves analyses with the experimental data showed that many of the simulation results and experimental data are relatively ***,notable discrepancies are found in the response amplitude operators for platform heave,tower base bending moment,and tension in mooring *** models give more satisfactory results of heave but more significant discrepan-cies in tower base bending moment than the me *** irregular wave analyses,low-frequency resonances were captured by PFT models with second-order difference-frequency terms,and high-frequency resonances were captured by the me models or PFT models with second-order sum-frequency *** force models capture the response frequencies but do not reasonably predict the response *** coupled wind/waves analyses showed more satisfactory results than the wave-only ***,an important detail to note is that this satisfactory result is based on the overprediction of wind-induced responses.

关键词： floating wind turbine wave force model potential flow theory Morison equation second-order wave forces

Effective Activation of melamine for Synchronous Synthesis of Catalytically Active Nanosheets and Fluorescence-Responsive Quantum Dots

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Transactions of Tianjin University 2024年第3期30卷 284-296页

作者： Jie Xuan Guijian Guan Ming-Yong han Institute of Molecular Plus Tianjin UniversityTianjin 300072China

Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior *** this study,we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation,which eff ectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets(CCN NSs)during hydrothermal *** a large specific surface area and increased light absorption,these CCN NSs demonstrate significantly enhanced photocatalytic activity in Co_(2) reduction,increasing the Co production rate by approximately tenfold compared with hexagonal melamine(h-me).Moreover,the product selectivity of CCN NSs reaches up to 93.5%to generate Co from Co_(2).Furthermore,the annealed CCN NSs exhibit a Co conversion rate of up to 95.30μmol/(g h),which indicates an 18-fold increase compared with traditional carbon *** the CCN NS synthesis,nitrogen-doped carbon quantum dots(NDC QDs)are simultaneously produced and remain suspended in the supernatant after *** QDs disperse well in water and exhibit excellent luminescent properties(QY=67.2%),allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04μmol/***,the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-eff ective and highly efficient process,yielding products with superior capabilities for catalytic conversion of Co_(2) and pollutant detection,respectively.

关键词： Carbon nitride Hydrothermal reaction Photocatalysis Carbon dioxide Quantum dots

Research on the cuttings discharge in air cushion chamber of slurry shield based on CFD-DEM coupling method Author links open overlay panel

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Particuology 2024年第8期91卷 88-105页

作者： han Wang Wantao Ding Weimin Yang Chengzhen Wang Wenduan Yu Zhicheng Wang School of Qilu Transportation Shandong UniversityJinan250002China China Railway 14th Bureau Group Co. LtdJinan250101China

The rapid discharge of cuttings from the air cushion chamber is crucial for the construction safety and excavation efficiency of the slurry *** studies have mainly focused on the transport characteristics of cuttings in the slurry discharge pipe,while the complete process of cuttings entering the slurry discharge pipe from the air cushion chamber until they are discharged was often *** on the CFD-DEM coupling method and combined with actual engineering,this paper established a numerical model that can more completely reflect the cuttings discharge process during slurry shield tunneling,and the effects of the slurry velocity at slurry gate and scouring pipes,inclination angle of slurry discharge pipe,cuttings diameter and shape coefficient were investigated by analyzing the variation in the mass flow rate,mass of discharged cuttings,and discharged *** results revealed that increasing the slurry velocity can promote the discharge of *** keep the discharged rate at a high level,it is recommended that the slurry velocity at the slurry gate should be greater than 0.15 m/*** the inclination angle of the discharge pipe is conducive to the rapid discharge of *** with large diameter or small shape coefficient are more prone to accumulate in the air cushion chamber and cause clogging *** research results not only help to improve engineers'understanding of cuttings discharge in slurry shield,but also provide practical guidance for formulating relevant construction measures.

关键词： Slurry shield CFD-DEM coupling method Cuttings discharge Aircushion chamber Slurry discharge pipe

Recent advances in visible light-mediated chemical transformations of enaminones

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Chinese Chemical Letters 2024年第2期35卷 4-15页

作者： Yu han Liyun Zhou Chengyu Wang Shangti Feng Rong Ma Jie-Ping Wan College of Chemistry and Chemical Engineering Jiangxi Normal UniversityNanchang 330022China School of Chemistry and Chemical Engineering Linyi UniversityLinyi 276000China Linyi Sanfeng Chemical Co. Ltd.Linyi 276000China

Enaminones,which possesses both the nucleophilic enamine as well as electrophilic enone structures,are well known versatile building blocks in organic ***,visible light-mediated reactions have emerged as useful synthetic strategy with enhanced *** the last decade,various photochemical transformations of enaminones have been developed to construct cyclic or acyclic *** this review,we describe the recent advances in visible light-mediated chemical transformations of *** discussion on the reaction me.hanism of the related reactions is given to provide guide to the ***,a summary on the existing challenges and the future outlook towards the development of practical photocatalytic reactions of enaminones is also presented.

关键词： Enaminone Visible light C-H functionalization C=C bond cleavage Cyclization Multicomponent reactions

Enhanced energy storage properties and good stability of novel(1-x)Na_(0.5)Bi_(0.5)Tio_(3)-xCa(Mg_(1/3)Nb_(2/3))o_(3) relaxor ferroelectric ceramics prepared by chemical modification

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Journal of Materiomics 2024年第4期10卷 770-782页

作者： Ying Zhang meng-han Yan Zhi-Fei Zhang Hai-Rui Bai Peng Li Wei-Fang han Ji-Gong Hao Wei Li Yu-Chao Li Chun-Ming Wang Peng Fu School of Materials Science and Engineering Liaocheng UniversityLiaocheng252059China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing 300 Changjiang RoadYantai264006China School of Physics Shandong UniversityJinan250100China

The increase in energy consumption and its collateral damage on the environment has encouraged the development of environment-friendly ceramic materials with good energy storage *** this work,(1-x)Na_(0.5)Bi_(0.5)Tio_(3)-xCa(Mg_(1/3)Nb_(2/3))o_(3) ceramics were synthesized by the solid-state reaction *** 0.88Na_(0.5)Bi_(0.5)Tio_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))o_(3) ceramic exhibited a high recoverable energy storage density of 8.1 J/cm3 and energy storage efficiency of 82.4% at 550 kV/*** introduction of Ca(Mg_(1/3)Nb_(2/3))o_(3) reduced the grain size and increased the band gap,thereby enhancing the breakdown field strength of the ceramic *** method also resulted in good temperature stability(20–140℃),frequency stability(1–200 Hz),and fatigue stability over 106 *** addition,an ultrahigh power density of 187 MW/cm^(3) and a fast charge-discharge rate(t0.9=57.2 ns)can be obtained *** element method analysis revealed that the decrease of grain size was beneficial to the increase of breakdown field ***,the 0.88Na_(0.5)Bi_(0.5)Tio_(3)-0.12Ca(Mg_(1/3)Nb_(2/3))o_(3) ceramics resulted in high energy storage properties with good stability and were promising environment-friendly materials for advanced pulsed power systems applications.

关键词： (1-x)Na_(0.5)Bi_(0.5)Tio_(3)-xCa(Mg_(1/3)Nb_(2/3))o_(3)ceramics Relaxor ferroelectrics Breakdown field strength Energy storage properties Stability

Effect of electrolyte cation-mediated me.hanism on electrocatalytic carbon dioxide reduction

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Chinese Chemical Letters 2024年第7期35卷 139-146页

作者： Yuan Dong Mutian Ma Zhenyang Jiao Sheng han Likun Xiong Zhao Deng Yang Peng Soochow Institute of Energy and Material Innovations College of EnergyJiangsu Key Laboratory of Advanced Carbon Materials and Wearable Energy TechnologiesSoochow UniversitySoochow 215006China Jiangsu Key Laboratory of Advanced Negative Carbon Technologies Soochow UniversitySoochow 215123China School of Chemistry and Chemical Engineering Shihezi UniversityShihezi 832003China School of Chemical and Environmental Engineering Shanghai Institute of TechnologyShanghai 201418China

The steep reduction in costs and systematic optimization of renewable electricity has ignited an intensifying interest in harnessing electroreduction of carbon dioxide(Co_(2)RR)for the generation of chemicals and *** focus of research over the past few decades has been on the optimization of the electrode and the electrolyte ***,cation species in the latter have recently been found to dramatically alter the selectivity of Co_(2)RR and even their catalytic activity by multiple orders of *** a result,the selection of cations is a critical factor in designing catalytic interfaces with high selectivity and efficiency for targeted *** decision-making regarding cation selection relies on a comprehensive understanding of prevailing electrolyte effect models that have been used to elucidate observed experimental *** this perspective,we review the hypotheses that explain how electrolyte cations influence Co_(2)RR by me.hanisms such as through tuning of the interfacial electric field,buffering of the local pH,stabilization of the key intermediates and regulation of the interfacial *** endeavor is to elucidate the molecular me.hanisms underpinning cation effects,thus fostering the evolution of more holistic and universally applicable predictive *** this regard,we highlight the current challenges in this area of research,while also identifying potential avenues for future investigations.

关键词： Co_(2)electrocatalytic reduction Cation effects Catalytic me.hanisms Catalytic interfaces Electric double layer

Examining the evolution of tidal creeks in the Huanghe River delta using multi-temporal Landsat images

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Journal of oceanology and Limnology 2024年第4期42卷 1061-1073页

作者： Zhen han Kai JIN Quanli ZoNG Peng QIN Chunxia LIU Xiuzhi ZHU Xinyue LI College of Resources and Environment Qingdao Agricultural UniversityQingdao 266109China

Coastal tidal creeks are important channels for exchanges of material and energy between sea and land,and play an important role in the ecological protection of tidal *** tidal creeks have evolved differently in various regions,the evolutionary process of tidal creeks in the Huanghe(Yellow)River delta of China,one of the most active deltas worldwide,is not entirely ***,the evolution of tidal creeks in the delta from 1981 to 2021 was investigated by quantitatively analysing the tidal creeks and developing a standard for dividing their evolution *** interpretation and supervised classification methods were applied to the Landsat images to extract the tidal creek network,and 17 groups of tidal creek systems were *** indicate that Creek S 1 was the most developed creek for having 113 tidal creeks totaling 65.8 km in length,while Creek E 3 had the fastest growth rate for having average annual increase of 1.9 ***,the level of tidal creeks increased,the average and median lengths of tidal creeks increased,and the number of tidal creeks decreased since *** evolution of the tidal creek system could be divided into four stages,namely,rising,developing,stabilizing,and *** of a representative tidal creek show that there was no degenerated tidal creek during the rising period,with an increase in the number of 50 and a length increase of 57.9 km between 1981 and *** proportion of new tidal creeks in the developing period was more than 50%and the new tidal creeks in the stabilizing period were equal to the degraded tidal *** tidal creeks were greater than 50%during the degrading *** was no fixed order of tidal creek evolution in each period,and there may be a skip in *** findings provided a reference for studying the evolution of tidal creeks.

关键词： tidal creek evolution pattern remote sensing Huanghe(Yellow)River delta

Experimental study on the operating performance of the air source heat pump(ASHP)with variable outdoor airflow rate under the standard frosting condition

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Energy and Built Environment 2024年第5期5卷 719-726页

作者： Shimin Liang han Wang Xuefeng Gao Xiaohui Tian Hui Zhu Songtao Hu Chunwen Lin School of Environmental and Municipal Engineering Qingdao University of TechnologyNo.11 Fushun RoadShibei DistrictQingdaoShandong 266033China Guangzhou Nenyin Heat Pump Technology Co. No.39Pangjiang Dongcun SectionShilian RoadDalong StreetPanyu DistrictGuangzhouGuangdong 511400China

Frosting is a common phenomenon of the ASHP under the heating mode in winter,and the outdoor air flow rate flowing through the evaporator of the ASHP was always thought to be a major *** order to validate its contribution,effects of outdoor fan airflow rate on the performance of air source heat pumps(ASHPs)were investigated under the winter heating *** experiment was conducted in a laboratory at the standard 2℃ air dry bulb temperature(DB)/1℃ air wet bulb temperature(WB)frosting condition,which enabled the analysis of the operating performance,frosting performance,and heating performance of the ASHP unit by changing the airflow rate of the outdoor *** showed that as the airflow rate of the outdoor fan reduced from 100%to 36%,the operating performance decline and the elevated frosting-defrosting loss were ***,both the frosting rate and the operating efficiency during frosting-defrosting cycles showed an increasing trend then followed by decreasing *** maximum frosting rate and operating efficiency were 0.92 g/m^(2).min and 2.92,respectively,which were observed at 74%airflow rate of the outdoor fan of the ASHP *** observation implied the existence of the“minimum frosting suppression airflow rate”.At 36%airflow rate of the outdoor fan of the ASHP unit,however,the performance of the ASHP unit was attenuated greatly,with the frosting-defrosting efficiency loss coefficient of 0.47,the heating capacity and CoP reduction by 51.5 and 38.8%,*** findings provided significant references to the optimization of ASHPs performance with variable airflow rate of the outdoor fan under frosting conditions.

关键词： ASHP Variable outdoor airflow rate Frosting Heating performance

Bi@C nanosphere anode with Na^(+)-ether-solvent cointercalation behavior to achieve fast sodium storage under extreme low temperatures

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Carbon Energy 2024年第9期6卷 325-337页

作者： Lingli Liu Siqi Li Lei Hu Xin Liang Wei Yang Xulai Yang Kunhong Hu Chaofeng Hou Yongsheng han Shulei Chou School of Energy Materials and Chemical EngineeringHefei UniversityHefeiChina LIB Technology Center of Anhui Province Hefei UniversityHefeiChina School of Advanced Manufacturing Engineering Hefei UniversityHefeiChina State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijingChina Institute for Carbon Neutralization College of Chemistry and Materials EngineeringWenzhou UniversityWenzhouChina

The low ion transport is a major obstacle for low-temperature(LT)sodium-ion batteries(SIBs).Herein,a core-shell structure of bismuth(Bi)nanospheres coated with carbon(Bi@C)is constructed by utilizing a novel Bi-based complex(1,4,5,8-naphthalenetetracarboxylic dianhydride as the ligand)as the precursor,which provides an effective template to fabricate Bi-based ***-40℃,the Bi@C anode achieves a high capacity,which is equivalent to 96%of that at 25℃,benefitting from the core-shell nanostructured engineering and Na^(+)-ether-solvent cointercalation *** special Na+-diglyme cointercalation behavior may effectively reduce the activation energy and accelerate the Na+diffusion kinetics,enabling the excellent low-temperature performance of the Bi@C *** expected,the fabricated Na_(3)V_(2)(Po_(4))_(3)//Bi@C full-cell delivers impressive rechargeability in the ether-based electrolyte at-40℃.Density functional theory calculations and electrochemical tests also reveal the fast reaction kinetic me.hanism at LT,thanks to a much lower diffusion energy barrier(167 meV)and a lower reaction activation energy(32.2 kJ mol^(-1))of Bi@C anode in comparison with that of bulk *** work provides a rational design of Bi-based electrodes for rechargeable SIBs under extreme conditions.

关键词： bismuth core-shell structure low-temperature conditions sodium-ion batteries