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The variation of microbiological characteristics in surface waters during persistent precipitation

Frontiers of Environmental Science & Engineering 2024年第9期18卷 67-78页

作者： xinyan Xiao Chenlan Chen Haoran li lihua li xin Yu College of the Environment&Ecology Xiamen UniversityXiamen 361102China Fujian Key Laboratory of Coastal Pollution Prevention and Control Xiamen UniversityXiamen 361102China

Climate change leads to an increase in both the frequency and intensity of extreme *** runoff generated by extreme precipitation has a significant impact on ***,the impact of persistent precipitation on surface water quality is easy to neglect,due to its prolonged duration and lower-intensity *** study established eight sampling points within selected surface waters to observe the variation of microbial characteristics in a typical persistence precipitation *** primary difference between Furong Lake(FL)and Chengqian Reservoir(CR)was:the concentrations of dissolved organic carbon(DOC)were 21.3±0.7 and 8.3±1.5 mg/L in FL and CR,*** concentrations of R2A culturable bacteria and coliforms were 10^(4.57)and 10^(1.58)colony-forming units(CFU)/mL in FL,and were 10^(5.46)and 10^(2.64)CFU/mL in CR,*** precipitation,the maximum increase concentrations of R2A,NA culturable bacteria,and coliforms were 10^(0.75),10^(1.30),and 10^(2.27)CFU/mL in FL,***,microbial concentration and rainfall did not increase simultaneously,and a delay phenomenon was observed in the increasing microbial *** analyzing the concentration change trends and correlation of various water quality indicators during persistent precipitation,the significant correlation between the DOC concentration and the changes in the dominant species of microbial community structure was found in this study(plined,the abundance of hgcl_clade and CL500-29_marine_group ***,although persistent precipitation might not obviously alter the water quality visibly,it could still pose potential microbial risks.

关键词： Rainfall Dissolved organic carbon Culturable bacteria Water quality Microbial community structure Climate change

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Vibration transfer from underground train to multi-story building:Modelling and validation with in-situ test data

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Underground Space 2024年第6期19卷 301-316页

作者： li Wang xin Gao Caiyou Zhao Ping Wang Zili li Section of Railway Engineering Delft University of TechnologyStevinweg 12628CN DelftThe Netherlands Key Laboratory of High-speed Railway Engineering(Southwest Jiaotong University) Ministry of EducationChengdu 610031China

Excessive underground train-induced vibration becomes a serious environmental problem in *** investigate the vibration transfer from an underground train to a building nearby,an explicit-integration time-domain,three-dimensional finite element model is *** underground train,track,tunnel,soil layers and a typical multi-story building nearby are all fully coupled in this *** complex geometries involving the track components and the building are all modelled in detail,which makes the simulation of vibration transfer more realistic from the underground train to the *** model is validated with in-situ tests data and good agreements have been achieved between the numerical results and the experimental results both in time domain and frequency *** proposed model is applied to investigate the vibration transfer along the floors in the building and the influences of the soil stiffness on the vibration characteristics of the track-tunnel-soil-building *** is found that the building vibration induced by an underground train is dominant at the frequency determined by the P2 resonance and influenced by the vibration modes of the *** vertical vibration in the building decreases in a fluctuant pattern from the foundation to the top floor due to loss of high frequency contents and local *** vibration levels in different rooms at a same floor can be different due to the different local stiffness.A room with larger space thus smaller local stiffness usually has higher vibration *** soil layers make the tunnel lining and the building have more low frequency *** influence of the soil stiffness on the amplification scale along the floors of the building is found to be nonlinear and frequency-dependent,which needs to be further investigated.

关键词： Railway vibration Underground train Multi-story building vibration Finite element model Dynamic interaction

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Zeolite-encaged gold catalysts for the oxidative condensation of furfural

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Frontiers of Chemical Science and Engineering 2024年第8期18卷 67-77页

作者： Weijie li Mingyang Gao Bin Qin xin Deng Landong li School of Materials Science and Engineering Nankai UniversityTianjin 300350China College of Chemistry Nankai UniversityTianjin 300071China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan *** selectivity control in this reaction process remains a significant ***,we report the strategy of confining well dispersed gold species within ZSM-5 structure to construct highly active Au@ZSM-5 zeolite catalysts for the oxidative condensation of *** results and spectroscopy analyses demonstrate the efficient encapsulation of isolated and cationic Au clusters in zeolite ***@ZSM-5(K)catalyst shows remarkable performance with 69.7%furfural conversion and 90.2%furan-2-acrolein selectivity as well as good recycle *** is revealed that the microstructure of ZSM-5 zeolite can significantly promote oxidative condensation activity through confinement *** work presents an explicit example of constructing zeolite encaged noble metal catalysts toward targeted chemical transformations.

关键词： zeolite encapsulation gold oxidative condensation furfural

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A molecular insight into coke formation process of vacuum residue in thermal cracking reaction

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Petroleum Science 2024年第3期21卷 2130-2138页

作者： Ji-Guang li xin Guo Huan-Di Hou Heavy Oil Processing Department Sinopec Research Institute of Petroleum Processing Co.LtdBeijing100083China

Understanding the coking behaviors has been considered to be really essential for developing better vacuum residue processing technologies.A battery of thermal cracking tests of typical vacuum residue at 410℃ with various reaction time were performed to evaluate the coke formation *** total yields of ideal components including naphtha,atmospheric gas oil(AGO)and vacuum gas oil(VGO)of thermal cracking reactions increased from 10.89%to 40.81%,and the conversion ratios increased from8.05%to 43.33%with increasing the reaction time from 10 to 70 *** asphaltene content increased from 12.14%to a maximum of 22.39%and then decreased,and this maximum of asphaltene content occurred at the end of the coking induction *** asphaltenes during the coking induction period,at the end and after coking induction period of those tested thermal cracking reactions were characterized to disclose the structure changing rules for coke formation process,and the coke formation pathways were discussed to reveal the coke formation process at molecular level.

关键词： Vacuum residue Thermal cracking Asphaltene Coking induction period Sulfur nitrogen

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Failure Analysis of Dissimilar Metal Welds between Ferritic Heat Resistant Steels and Austenitic Stainless Steels in Power Plant

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 306-326页

作者： Xiaogang li Junfeng nie xin Wang Kejian li Haiquan Zhang Institute of Nuclear and New Energy Technology Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

This study analysed the failure of dissimilar metal welds(DMWs)between ferritic heat resistant steels and austenitic stainless steels and investigated its influencing factors by means of numerical simulation,microstructure characterization and mechanical property *** the long-term high-temperature service condition in practical power plant,the DMW failure mode was along the interface between nickel-based weld metal(WM)and ferritic heat resistant steel,and the failure mechanism was stress/strain concentration,microstructure degradation and oxidation coupling acting on the *** numerical simulation results show that interface stress/strain concentration was due to the differences in coefficient of thermal expansion and creep strength,and the degree of stress/strain concentration was related to service *** ferrite band formed at the WM/ferritic steel interface was prone to cracking,attracting the fracture along the *** interface crack allowed oxidation to develop along the WM/ferritic steel *** long-term service,the interface stress/strain concentration,microstructure and oxidation all evolved,which synergistically promoted interface failure of ***,only under the long-term service of low stress conditions could trigger the interface failure of ***,long-term service would reduce the mechanical strength and plasticity of DMW.

关键词： Dissimilar metal weld Failure Interface Stress/strain concentration Microstructure Oxidation

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Collision-free parking recommendation based on multi-agent reinforcement learning in vehicular crowdsensing

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Digital Communications and Networks 2024年第3期10卷 609-619页

作者： xin li xinghua Lei Xiuwen liu Hang Xiao College of Computer Science and Technology China University of Petroleum(East China)QingDao266580China

The recent proliferation of Fifth-Generation(5G)networks and Sixth-Generation(6G)networks has given rise to Vehicular Crowd Sensing(VCS)systems which solve parking collisions by effectively incentivizing vehicle ***,instead of being an isolated module,the incentive mechanism usually interacts with other *** on this,we capture this synergy and propose a Collision-free Parking Recommendation(CPR),a novel VCS system framework that integrates an incentive mechanism,a non-cooperative VCS game,and a multi-agent reinforcement learning algorithm,to derive an optimal parking strategy in real ***,we utilize an LSTM method to predict parking areas roughly for recommendations *** incentive mechanism is designed to motivate vehicle participation by considering dynamically priced parking tasks and social network *** order to cope with stochastic parking collisions,its non-cooperative VCS game further analyzes the uncertain interactions between vehicles in parking *** its multi-agent reinforcement learning algorithm models the VCS campaign as a multi-agent Markov decision process that not only derives the optimal collision-free parking strategy for each vehicle independently,but also proves that the optimal parking strategy for each vehicle is ***,numerical results demonstrate that CPR can accomplish parking tasks at a 99.7%accuracy compared with other baselines,efficiently recommending parking spaces.

关键词： Incentive mechanism Non-cooperative VCS game Multi-agent reinforcement learning Collision-free parking strategy Vehicular crowdsensing

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Origin and evolution of false brinelling and fretting corrosion under rolling conditions

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Friction 2024年第4期12卷 618-631页

作者： xin JIA Lu HUANG Miao SUN Wenbin li National Institute of Metrology Beijing 100029China Yantai Tiancheng Machinery Co. Ltd.Yantai 264006China

Rolling bearings working in oscillating applications often suffer from false brinelling and fretting corrosion that limit their service *** present,the study of oscillation-induced failures is primarily dominated by a large number of sliding and bench ***,most of the previous work are not able to fully describe the two closely related but different failure *** this study,the origin and evolution of the two failures are thoroughly investigated under strictly controlled oscillating rolling *** results show that failure evolves from false brinelling to fretting corrosion under dry friction conditions regardless of the oscillation *** process is accompanied by a large area peeling and serious oxidation,and the oxygen content increases from 2.50 wt%to 21.22 wt%.Oxidation is a crucial factor in the evolution of false brinelling into fretting ***,the distribution of microwear and oxygen content depend on the oscillation *** lubrication conditions,the friction coefficient(COF)is smaller in the initial stage and led to local slip or transient instability of rolling ***,the size of the wear marks and COF increased and appeared to be larger than those under a dry friction ***,grease can separate the contact surfaces,only surface deformation owing to false brinelling and slight damage at the roughness level *** evolution of false brinelling and fretting corrosion is also closely related to residual *** brinelling often occurrs with residual stress accomulation,meanwhile,the residual stress increases from 120 to 300 *** peeling occurs,residual stress is *** failure pattern transformed from false brinelling to fretting corrosion and is accompanied by *** far,none of investigation is able to show satisfactory evolution of oscillating-induced failures,this study may contribute to more scientific understanding of rolling bearings against long-

关键词： oscillating false brinelling fretting corrosion wear residual stress

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Classification and spectrum optimization method of grease based on infrared spectrum

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Friction 2024年第6期12卷 1154-1164页

作者： xin FENG Yanqiu XIA Peiyuan XIE Xiaohe li School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

The infrared(IR)absorption spectral data of 63 kinds of lubricating greases containing six different types of thickeners were obtained using the IR *** Kohonen neural network algorithm was used to identify the type of the lubricating *** results show that this machine learning method can effectively eliminate the interference fringes in the IR spectrum,and complete the feature selection and dimensionality reduction of the high-dimensional spectral *** 63 kinds of greases exhibit spatial clustering under certain IR spectrum recognition spectral bands,which are linked to characteristic peaks of lubricating greases and improve the recognition accuracy of these *** model achieved recognition accuracy of 100.00%,96.08%,94.87%,100.00%,and 87.50%for polyurea grease,calcium sulfonate composite grease,aluminum(Al)-based grease,bentonite grease,and lithium-based grease,*** on the different IR absorption spectrum bands produced by each kind of lubricating grease,the three-dimensional spatial distribution map of the lubricating grease drawn also verifies the accuracy of classification while recognizing the *** paper demonstrates fast recognition speed and high accuracy,proving that the Kohonen neural network algorithm has an efficient recognition ability for identifying the types of the lubricating grease.

关键词： grease infrared(IR)spectroscopy layered Kohonen network species recognition spectrum band optimization

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Probabilistic seismic inversion based on physics-guided deep mixture density network

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Petroleum Science 2024年第3期21卷 1611-1631页

作者： Qian-Hao Sun Zhao-Yun Zong xin li National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Laoshan Laboratory Qingdao266580ShandongChina CNOOC Research Institute Ltd. Beijing100028China

Deterministic inversion based on deep learning has been widely utilized in model parameters *** by logging data,seismic data,wavelet and modeling operator,deterministic inversion based on deep learning can establish nonlinear relationships between seismic data and model ***,seismic data lacks low-frequency and contains noise,which increases the non-uniqueness of the *** conventional inversion method based on deep learning can only establish the deterministic relationship between seismic data and parameters,and cannot quantify the uncertainty of *** order to quickly quantify the uncertainty,a physics-guided deep mixture density network(PG-DMDN)is established by combining the mixture density network(MDN)with the deep neural network(DNN).Compared with Bayesian neural network(BNN)and network dropout,PG-DMDN has lower computing cost and shorter training time.A low-frequency model is introduced in the training process of the network to help the network learn the nonlinear relationship between narrowband seismic data and low-frequency *** addition,the block constraints are added to the PG-DMDN framework to improve the horizontal continuity of the inversion *** illustrate the benefits of proposed method,the PG-DMDN is compared with existing semi-supervised inversion *** synthetic data examples of Marmousi II model are utilized to quantify the influence of forward modeling part,low-frequency model,noise and the pseudo-wells number on inversion results,and prove the feasibility and stability of the proposed *** addition,the robustness and generality of the proposed method are verified by the field seismic data.

关键词： Deep learning Probabilistic inversion Physics-guided Deep mixture density network

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Highly selective electrosynthesis of 3,4-dihydroisoquinoline accompanied with hydrogen production over three-dimensional hollow Coni-based microarray electrocatalysts

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Nano Research 2024年第4期17卷 2509-2519页

作者： Yu xin liyu Chen Yingwei li Kui Shen Guangdong Provincial Key Lab for Green Chemical Product Technology School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China State Key Laboratory of Pulp and Paper Engineering School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhou 510640China

Electrocatalytic oxidation reaction of biomass-based derivatives is an excellent candidate to replace water oxidation for obtaining both value-added products and hydrogen(H_(2)),but the exploration of competent electrocatalysts is still highly ***,two new types of three-dimensional self-supported hollow microarrays containing Coni layered double hydroxide(Coni-LDH)and N-doped carbon nanosheets decorated with Coni alloyed nanoparticles(Coni-NC)on carbon cloth(CC)are prepared,which are further used as efficient electrocatalysts for tetrahydroisoquinoline(THIQ)electrooxidation and hydrogen evolution reaction(HER),*** demonstrate that the Co-modulated electronic environment for ni(II)/ni(Ⅲ)redox-looping in Coni-LDH is the main factor to boost the selectivity of 3,4-dihydroisoquinoline(DHIQ)for the indirect electrooxidation process of *** functional theory(DFT)calculations reveal that the ni(Ⅲ)/Co(Ⅲ)dual sites of Coni-LDH exhibit enhanced adsorption for THIQ but poorer adsorption for DHIQ compared to pure Co(Ⅲ)or ni(Ⅲ).Therefore,the ni(Ⅲ)/Co(Ⅲ)dual sites can effectively inhibit the peroxidation of DHIQ to isoquinoline(IQ)over Coni-LDH,thus improving the selectivity of DHIQ to nearly 100%,much higher than that of its pure ni ***,CC@Coni-NC can deliver high HER activity with low overpotential(40 mV@10 mA·cm^(-2))and high exchange current density(3.08 mA·cm^(-2)).Impressively,the assembled flow-cell device with CC@Coni-LDH anode and CC@Coni-NC cathode only requires low cell voltage and electricity consumption of 1.6 V and 3.50 kWh per cubic meter of H_(2)(@25 mA·cm^(-2)).

关键词： highly selective electrosynthesis dihydroisoquinolines hydrogen evolution reaction metal-organic frameworks hollow microarrays

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