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Particle size dependence of the microsegregation and microstructure in the atomized Ni-based superalloy powders:Theoretical and experimental study

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Journal of Materials Science & Technology 2024年第4期171卷 54-65页

作者： Jikang Li Mingsheng Yang Yunfei Cai Yuanyuan zhang Qingshuai Feng Jiantao Liu Tong Liu Key Laboratory of Aerospace Materials and Performance(Ministry of Education)School of Materials Science and Engineering Beihang UniversityBeijing 100191China Central Iron and Steel Research Institute Beijing 100081China

The microstructure and microsegregation of atomized powder,which depend on their sizes,are of great importance to the mechanical properties of the consolidated bulk ***,it is necessary to reveal the relationship between particle size and powder *** effects of particle size on the so-lidification characterization of the atomized Ni-based superalloy powders were studied via finite element *** on the simulations,a model was developed to predict the microsegregation and mi-crostructure of atomized powders with different sizes and study the influence of thermal history on the powder attributes during the atomization *** radiation heat transfer and temperature gradi-ent within the rapid solidification alloy powders were taken into account in this *** validating the accuracy of the model,the predictions of the present model were compared with the microsegregation and microstructure of the specific size powder close to the screen mesh *** results showed that mi-crostructure depended primarily on the temperature gradient within the powder,while the solidification rate had a more significant effect on the *** model predicted microstructure features in agreement with the experiment,and for microsegregation,the deviations of prediction for most ele-ments were less than 10%.This work provides a new model to precisely predict the microsegregation and microstructure of the atomized alloy powders and sets a foundation to control the powder features for various engineering applications.

关键词： Particle size Solidification microstructure Microsegregation Numerical simulation

Supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions

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Chinese Journal of Chemical Engineering 2024年第5期69卷 220-226页

作者： Xinyue Duan Zeyu zhang Ziyuan Zhao Yang Liu Liang Gong Xuewen Cao Jiang Bian College of New Energy China University of Petroleum(East China)Qingdao 266580China College of Pipeline and Civil Engineering China University of Petroleum(East China)Qingdao 266580China

This paper introduced supersonic expansion liquefaction technology into the field of hydrogen *** mathematical model for supersonic condensation of hydrogen gas in a Laval nozzle model was *** supersonic expansion and condensation characteristics of hydrogen gas under different temperature conditions were *** simulation results show that the droplet number rises rapidly from 0 at the nozzle throat as the inlet temperature increases,and the maximum droplet number generated is 1.339×10^(18)kg^(-1)at inlet temperature of 36.0 *** hydrogen nucleation occurs,the droplet radius increases significantly and shows a positive correlation with the increase in the inlet temperature,and the maximum droplet radii are 6.667×10^(-8)m,1.043×10^(-7)m,and 1.099×10^(-7)m when the inlet temperature is 36.0 K,36.5 K,and 37.0 K,*** maximum nucleation rate decreases with increasing inlet temperature,and the nucleation region of the Laval nozzle becomes *** liquefaction efficiency can be effectively improved by lowering the inlet *** is because a lower inlet temperature provides more subcooling,which allows the hydrogen to reach the thermodynamic conditions required for large-scale condensation more quickly.

关键词： Hydrogen Liquefaction Supersonic Condensation Laval nozzle Computational fluid dynamics

Dynamic Analysis of a 10 MW Floating Offshore Wind Turbine Considering the Tower and Platform Flexibility

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Journal of Ocean University of China 2024年第2期23卷 358-370页

作者： GAO Shan zhang Lixian SHI Wei WANG Wenhua WANG Bin LI Xin Key Laboratory of Far-Shore Wind Power Technology of Zhejiang Province Hangzhou 311122China State Key Laboratory of Coastal and Offshore Engineering Deepwater Engineering Research CenterDalian University of TechnologyDalian 116024China Powerchina Huadong Engineering Corporation Limited Hangzhou 311122China Faculty of Infrastructure Engineering Dalian University of TechnologyDalian 116024China Ningbo Institute of Dalian University of Technology Ningbo 315000China

Recently,semisubmersible floating offshore wind turbine technologies have received considerable *** the coupled simulation of semisubmersible floating offshore wind energy,the platform is usually considered a rigid model,which could affect the calculation accuracy of the dynamic *** dynamic responses of a TripleSpar floating offshore wind turbine equipped with a 10 MW offshore wind turbine are discussed *** simulation of a floating offshore wind turbine under regular waves,white noise waves,and combined wind-wave conditions is *** effects of the tower and platform flexibility on the motion and force responses of the TripleSpar semisubmersible floating offshore wind turbine are *** results show that the flexibility of the tower and platform can influence the dynamic responses of a TripleSpar semisubmersible floating offshore wind *** the flexibility of the tower and platform,the tower and platform pitch motions markedly increased compared with the fully rigid ***,the force responses,particularly for tower base loads,are considerably influenced by the flexibility of the tower and ***,the flexibility of the tower and platform for the coupled simulation of floating offshore wind turbines must be appropriately examined.

关键词： floating offshore wind turbine TripleSpar semisubmersible platform rigidity and flexibility platform coupled simulation

Novel self-assembled porous yolk-shell NiO nanospheres with excellent electrochromic performance for smart windows

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Particuology 2024年第1期84卷 72-80页

作者： Baoshun Wang Ya Huang Siming Zhao Run Li Di Gao Hairong Jiang Rufan zhang Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing100084China

With the rapid development of optoelectronics,electrochromic(EC)materials(ECMs)with the advan-tages of low power consumption,easy viewing,high contrast ratio,etc have attached more and more attention from the fields of smart windows,electronic billboards,emerging wearable and portable electronics,and other next-generation *** oxide(NiO)is a promising candidate for high-performance ECMs because of its neutral-colored states and low ***,NiO-based ECMs still face the problem of slow switching speed due to their low electrical conductivity and small lattice ***-organic frameworks(MOFs)are promising candidates to fabricate hollow and porous transition metal oxides(TMOs)with high ion transport efficiency,excellent specific capacitance,and electrochemical *** this work,porous yolk-shell NiO nanospheres(PYS-NiO NSs)were syn-thesized via a solvothermal and subsequent calcination process of Ni-MOF,which exhibited outstanding EC *** the large specific surface areas and hollow porous nanostructures were conducive to ionic transport,PYS-NiO NSs exhibited a fast coloring/bleaching speed(3.6/3.9 s per one coloring/bleaching cycle)and excellent cycling stability(82%of capacity retention after 3000 cycles).These superior EC properties indicated that the PYS-NiO NSs was a promising candidate for high-performance EC *** work provides a new and feasible strategy for the efficient preparation of TMOs ECMs with good EC performance,especially fast switching speed.

关键词： Electrochromic Nickel oxide Metal-organic frameworks Hollow structure Smart windows

Occurrence of viable but non-culturable(VBNC)pathogenic bacteria in tap water of public places

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Frontiers of Environmental Science & Engineering 2024年第3期18卷 115-129页

作者： Lizheng Guo Xinyan Xiao Kassim Chabi Yiting zhang Jingjing Li Su Yao Xin Yu China National Research Institute of Food and Fermentation Industries Co. Ltd.China Center of Industrial Culture CollectionBeijing 100015China Key Laboratory of Urban Environment and Health Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China College of Environment&Ecology Xiamen UniversityXiamen 361102China

Viable but non-culturable(VBNC)bacteria have been detected in source water and effluent of drinking water treatment processes,leading to significant underestimation of viable cell *** information exists on VBNC bacteria in tap water,particularly in public *** address this gap,a comprehensive nine-month study was conducted in a major city in south-eastern China,using culture-based and quantitative PCR with propidium monoazide(PMA)dye ***-five samples were collected from five representative public places(railway station,campus,hospital,shopping mall,and institution).The findings revealed that culturable bacteria represented only 0–17.51%of the viable 16S rRNA genes,suggesting that the majority of viable bacteria existed in an uncultured or VBNC ***,opportunistic pathogens such as Escherichia coli,Enterococcus faecalis,Pseudomonas aeruginosa,Salmonella sp.,and Shigella *** primarily detected as VBNC cells,with concentrations ranging from 1.03×10^(0)to 3.01×10^(3),1.20×10^(0)to 1.42×10^(2),1.32×10^(0)to 8.82×10^(0),1.00×10^(0)to 6.71×10^(1),and 2.07×10^(0)to 1.93×10^(2)cell equivalent/100 mL,*** *** was observed in tap water after prolonged stagnation,indicating potential risks associated with bacterial *** and temporal factors accounted for 17.1%and 26.0%,respectively,of the variation in tap water community structure during the sampling period,as revealed by 16S rRNA amplicon *** study provides quantitative insights into the occurrence of VBNC bacteria in tap water and highlights the need for more sensitive monitoring methods and microbial control techniques to enhance tap water safety in public locations.

关键词： VBNC Pathogenic bacteria PMA treatment Public tap water Community structure

B-COPNA resin formation from ethylene tar light fractions:Process development and mechanical exploration by molecular simulation

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Chinese Journal of Chemical Engineering 2024年第6期70卷 118-129页

作者： Hongyan Shen Lingrui Cui Xingguo Wei Yuanqin zhang Lian Cen Jun Xu Fahai Cao Engineering Research Center of Large Scale Reactor East China University of Science and TechnologyShanghai 200237China

An efficient utilization strategy of ethylene tar(ET),the main by-product of the ethylene cracking unit,is urgently required to meet demands for modern petrochemical *** the other hand,condensed polynuclear aromatic resin of moderate condensation degree(B-COPNA)is a widely used carbon material due to its superb processability,the production of which is,however,seriously limited by the high cost of raw *** such context,an interesting strategy was proposed in this study for producing B-COPNA resin using crosslinked light fractions of ethylene tar(ETLF,boiling point<260℃)facilitated by molecular simulation.1,4-Benzenedimethanol(PXG)was first selected as the crosslinking agent according to the findings of molecular *** effects of operating conditions,including reactions temperature,crosslinking agent,and catalyst content on the softening point and yield of B-COPNA resin products were then investigated to optimize the *** reaction mechanism of resin production was studied by analyzing the molecular structure and transition state of ETLF and crosslinking *** was shown that PXG exhibited a superior capacity of withdrawing electrons and a higher electrophilic reactivity than other crosslinking *** addition to the highest yield and greatest heat properties,PXG-prepared resin contained the most condensed *** corresponding optimized conditions of resin preparation were 180℃,1:1.9(PXG:ETLF),and 3%(mass)of catalyst content with a resin yield of 78.57%.It was the electrophilic substitution reaction that occurred between the ETLF and crosslinking agent molecules that were responsible for the resin formation,according to the experimental characterization and molecular ***,it was confirmed that the proposed strategy and demonstrated process can achieve a clean and high value-added utilization of ETLF via B-COPNA resin preparation,bringing huge economic value to the current petrochemical industry.

关键词： Ethylene tar Crosslinking COPNA resin Molecular simulation Transient state

Microstructure,mechanical and fracture properties of friction stir welded 2195 Al-Li alloy joints

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Chinese Journal of Aeronautics 2024年第1期37卷 345-361页

作者： Guangda SUN Weizhao SUN Li ZHOU Sanfeng LUO Zili zhang Debo LIU Huiqiang WU State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China Shandong Provincial Key Laboratory of Special Welding Technology Harbin Institute of Technology(Weihai)Weihai 264209China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

The 8 mm-thick 2195 Al-Li alloy joints were achieved by Friction Stir Welding(FSW).The microstructural evolution,temperature-dependent mechanical properties,and fracture properties were *** T1,δ’/β’and θ’precipitates were observed in the Base Metal(BM)and the Heat Affected Zone(HAZ).Most of the precipitates,except for re-precipitated δ’/β’phases,were dissolved in the Nugget Zone(NZ).The tensile specimens that failed at cryogenic temperatures(-196℃)had the maximum Ultimate Tensile Strength(UTS),and the fracture surface showed the inter-granular fracture *** to those at room temperature(25℃),the decreasing tensile properties at high temperature(180℃)were related to microstructure and strain hardening *** NZ presented the optimal fracture toughness,and the Crack Tip Opening Displacement(CTOD)was mutually dominated by microhardness and grain *** on Fatigue Crack Growth(FCG)rates indicates that the Thermal-Mechanically Affected Zone(TMAZ)exhibited the most superior fatigue resistance performance at stress intensity range below17 MPa.m1/2due to compressive residual stress and the crack closure *** fatigue fracture surfaces reveal that the crack propagation zone was characterized by the striations and secondary ***,inter-granular fracture behavior was responsible for the fastest FCG rates in the NZ.

关键词： Aluminum alloys Friction stir welding Microstructural evolution Mechanical properties Fracture mechanism

Chemical Scissors Tailored Nano‑Tellurium with High‑Entropy Morphology for Efficient Foam‑Hydrogel‑Based Solar Photothermal Evaporators

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Nano-Micro Letters 2024年第3期16卷 149-168页

作者： Chenyang Xing Zihao Li Ziao Wang Shaohui zhang Zhongjian Xie Xi Zhu Zhengchun Peng State Key Laboratory of Radio FrequencyHeterogeneous Integration Shenzhen UniversityShenzhen 518060People’s Republic of China Center for Stretchable Electronics and NanoSensors College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060People’s Republic of China School of Science and Engineering The Chinese University of Hong KongShenzhenShenzhen 518172People’s Republic of China Institute of Pediatrics Shenzhen Children’s HospitalShenzhen 518038GuangdongPeople’s Republic of China International Collaborative Laboratory of 2D Materials for Optoelectronics Science and Technology of Ministry of Education Institute of Microscale OptoelectronicsShenzhen UniversityShenzhen 518060People’s Republic of China

The development of tellurium(Te)-based semiconductor nanomaterials for efficient light-to-heat conversion may offer an effective means of harvesting sunlight to address global energy ***,the nanosized Te(nano-Te)materials reported to date suffer from a series of drawbacks,including limited light absorption and a lack of surface ***,we report the preparation of nano-Te by electrochemical exfoliation using an electrolyzable room-temperature ionic ***,cations,and their corresponding electrolytic products acting as chemical scissors can precisely intercalate and functionalize bulk *** resulting nano-Te has high morphological entropy,rich surface functional groups,and broad light *** also constructed foam hydrogels based on poly(vinyl alcohol)/nano-Te,which achieved an evaporation rate and energy efficiency of 4.11 kg m^(−2)h^(−1)and 128%,respectively,under 1 sun ***,the evaporation rate was maintained in the range 2.5-3.0 kg m^(−2)h^(−1)outdoors under 0.5-1.0 sun,providing highly efficient evaporation under low light conditions.

关键词： Tellurium High entropy Electrochemical modification Solar absorption Evaporation rate

A method for establishing a bearing residual life prediction model for process enhancement equipment based on rotor imbalance response analysis

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Chinese Journal of Chemical Engineering 2024年第2期66卷 203-215页

作者： Feng Wang Haoran Li Zhenghui zhang Yan Bai Hong Yin Jing Bian National Foundation Research Laboratory of Fault Prevention and Control in Hazardous Chemicals Production System Engineering Research Center of Chemical Technology SafetyBeijing University of Chemical TechnologyBeijing 100029China China Nuclear Power Engineering Co. LtdBeijing 100840China CNOOC Tianjin Chemical Research and Design Institute Co. LtdTianjin Key Laboratory of Energy and Chemical Explosion SafetyAcademician Expert Collaborative Innovation CenterTianjin 300131China

A rotating packed bed is a typical chemical process enhancement equipment that can strengthen micromixing and mass *** the operation of the rotating packed bed,the nonreactants and products irregularly adhere to the wire mesh packing in the rotor,thus resulting in an imbalance in the vibration of the rotor,which may cause serious damage to the bearing and material *** study proposes a model prediction for estimating the bearing residual life of a rotating packed bed based on rotor imbalance response *** method is used to determine the influence of the mass on the imbalance in the vibration of the rotor on bearing *** major influence on rotor vibration was found to be exerted by the imbalanced mass and its distribution radius,as revealed by the results of orthogonal *** implementing finite element analysis,the imbalance response curve for the rotating packed bed rotor was obtained,and a correlation among rotor imbalance mass,distribution radius of imbalance mass,and bearing residue life was established via data *** predicted value of the bearing life can be used as the reference basis for an early safety warning of a rotating packed bed to effectively avoid accidents.

关键词： Rotating packed bed Mass imbalance Harmonic response analysis Residual life Prediction model