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Particle effects on the hydrodynamics in slurry bubble column reactors:A review from multiscale mechanisms Author links open overlay panel

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Particuology 2024年第8期91卷 176-189页

作者： min An Jingqi Gao Tiankuo Wang Xiangnan li National Supercomputing Center in Zhengzhou Zhengzhou UniversityZhengzhou450001China School of Chemical Engineering and New Energy Xiamen University MalaysiaSepangSelangor43900Malaysia School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiang453007China

Particles can appear as catalyst,reactant or product in various gas-liquid-solid three-phase production *** bubble column reactors(SBCRs),as a kind of three-phase reactors,are preferred for phase contacting and ***,literature studies concerning the effects of particles on the hydrodynamics of SBCRs are manifold and inconsistent in ***,the multiscale interactions between particles,turbulent eddies and bubbles determine the reactor *** review focuses on revealing the particle effects in SBCRs from the perspective of multiscale *** hydrodynamic changes due to particle effects in literature are *** parameters,including the Stokes number,the solid-to-liquid density ratio,the ratio of particle and liquid characteristic lengths,the contact angle and the particle volume fraction are adopted to evaluate the characteristics of gas-liquid-solid *** relationships between particle influencing mechanisms and these parameters are analyzed and *** experimental results are explained by different ranges of these dimensionless ***,particle effects at the mesoscale and microscale,such as the influence on the bubble dynamics and the pivoting effect on the turbulence energy spectrum,are ***,progress in modeling the SBCRs with consideration of particles effects using the Euler method are *** review aims to improve the overall understanding of the complex hydrodynamics in the SBCRs.

关键词： Slurry bubble column reactors Particle effects Turbulence characteristics Bubble dynamics CFD

Bioinspired Double-stranded Yarn with Alternating Hydrophobic/Hydrophilic Patterns for High-efficiency Fog Collection

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Chinese Journal of Polymer Science 2024年第7期42卷 968-975,I0008页

作者： Lan-Lan Hou Meng-Na Qiu Ya-Qiong Wang Tong-Hua Bai Zhi-min Cui Jing-Chong liu Ying-Qun Qi Nü Wang yong li yong Zhao Beijing Institute of Graphic Communication Beijing102600China Key Laboratory of Bioinspired Smart Interfacial Science and Technology of ministry of Education Beijing Key Laboratory of Bioinspired Energy Materials and DevicesSchool of ChemistryBeijing Advanced Innovation Center for Biomedical EngineeringBeihang UniversityBeijing100191China Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China Beijing Key Laboratory for Bioengineering and Sensing TechnologyDaxing Research InstituteSchool of Chemistry and Biological EngineeringUniversity of Science and Technology BeijingBeijing100083China

Efforts to develop innovative water harvesting strategies offer powerful solutions to alleviate the water crisis,especially in remote and arid *** by the hydrophobic/hydrophilic pattern of desert beetles and water self-propulsion property of spider silks,a double-strand hydrophobic PVDF-HFP/hydrophilic PAN nanofibers yarn is proposed by electrospinning and twisting *** double-strand cooperation approach allows for water deposition on hydrophobic PVDF-HFP segment and transport under the asymmetric capillary driving force of hydrophilic PAN segment,thus speeded up the aggregation and growth of *** effects of the composition and the diameter ratio of the two primary yarns were studied and optimized for boosting fog collection *** double-strand anisotropic yarn not only provide an effective method for water harvesting,but also hold the potential to inspire innovative design concepts for fog collection materials in challenging environments.

关键词： Fog collection Wettability Electrospinning Nanofibers Spider silk

An Approximation Algorithm Based on Seeding Algorithm for Fuzzy k-Means Problem with Penalties

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Journal of the Operations Research Society of China 2024年第2期12卷 387-409页

作者： Wen-Zhao liu min li School of Mathematics and Statistics Shandong Normal UniversityJinan 250014ShandongChina

As a classic NP-hard problem in machine learning and computational geometry,the k-means problem aims to partition the given dataset into k clusters according to the minimal squared Euclidean *** from k-means problem and most of its variants,fuzzy k-means problem belongs to the soft clustering problem,where each given data point has relationship to every center *** to fuzzy k-means problem,fuzzy k-means problem with penalties allows that some data points need not be clustered instead of being paid *** this paper,we propose an O(αk In k)-approximation algorithm based on seeding algorithm for fuzzy k-means problem with penalties,whereαinvolves the ratio of the maximal penalty value to the minimal ***,we implement numerical experiments to show the effectiveness of our algorithm.

关键词： Approximation algorithm Seeding algorithm Fuzzy k-means problem with penalties

Hydrothermal hydrogenation/deoxygenation of palmitic acid to alkanes over Ni/activated carbon catalyst

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Chinese Journal of Chemical Engineering 2024年第2期66卷 8-18页

作者： min lin Yuhao Yan Xiaoxian li Rui li Yulong Wu MOE Engineering Center of Forestry Biomass Materials and Bioenergy Beijing Forestry UniversityBeijing 100083China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Key Laboratory of Advanced Reactor Engineering and Safety of ministry of Education Tsinghua UniversityBeijing 100084China

To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent *** order to avoid energy-intensive separation process of water and bio-oil,it is of importance that deoxygenation upgrading of fatty acids under hydrothermal conditions similar to HTL ***,it is the first time to explore the application of activated carbon(AC)-supported non-noble-metal catalysts,such as Ni,Co,and Mo,and so on,in the hydrothermal hydrogenation/deoxygenation of long-chain fatty acids,and the obtained Ni/AC-H(the Ni/AC was further H_(2)pre-reduced)is one of the best *** addition,it is found that the catalytic activity can be further improved by H_(2)pre-reduction of *** results that are more low valences of nickel and oxygen vacancy can be obtained after H_(2)pre-reduction,thus significant promoting the deoxygenation especially the decarbonylation pathway of fatty *** total alkanes yield can reaches 95.9%at optimal conditions(280℃,360 min).This work confirmed that the low-priced AC-supported non-noble-metal catalysts have great potential compared with the noble-metal catalyst,in hydrothermal upgrading of bio-oil.

关键词： Bio-oil Fatty acids Deoxygenation Hydrothermal upgrading

The dynamics beamline at SSRF

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Nuclear Science and Techniques 2024年第9期35卷 56-67页

作者： Zhen liu li-Hua Wang yong Jiang Ya-Jun Tong Hua-Chun Zhu Te Ji min Chen Zheng Jiang Xiang-Jun Wei Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201204China ShanghaiTech University Shanghai 201210China

The dynamics beamline(D-line),which combines synchrotron radiation infrared spectroscopy(SR-IR)and energy-disper-sive X-ray absorption spectroscopy(ED-XAS),is the first beamline in the world to realize concurrent ED-XAS and SR-IR measurements at the same sample position on a millisecond time-resolved *** combined technique is effective for investigating rapid structural changes in atoms,electrons,and molecules in complicated disorder systems,such as those used in physics,chemistry,materials science,and extreme ***,ED-XAS and SR-IR can be used independently in the two branches of the *** ED-XAS branch is the first ED-XAS beamline in China,which uses a tapered undulator light source and can achieve approximately 2.5×10^(12)photons/s·300 eV BW@7.2 keV at the sample *** exchange-able polychromator operating in the Bragg-reflection or Laue-transmission configuration is used in different energy ranges to satisfy the requirements for beam size and energy *** focused beam size is approximately 3.5μm(H)×21.5μm(V),and the X-ray energy range is 5–25 *** one-and two-dimensional position-sensitive detectors with frame rates of up to 400 kHz enables time resolutions of tens of microseconds to be *** distinctive techniques,such as the concurrent measurement of in situ ED-XAS and infrared spectroscopy,time-resolved ED-XAS,high-pressure ED-XAS,XMCD,and pump-probe ED-XAS,can be applied to achieve different scientific goals.

关键词： ED-XAS SR-IR Time-resolved D-line SSRF

Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation

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Journal of Bionic Engineering 2024年第4期21卷 1662-1676页

作者： min Chang Ziyi Xu Zengshuang Chen li li Xueguang Meng Unmanned System Research Institute National Key Laboratory of Unmanned Aerial Vehicle TechnologyNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China Xi’an Aeronautics Computing Technique Research Institute Aviation Industry Corporation of ChinaXi’an710076People’s Republic of China

To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this *** from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole *** is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each *** the whole flapping cycle,three effects are at *** narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the *** also shows that these effects could be manipulated by changing the spacing between adjacent *** findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.

关键词： Three flapping wings Unequal spacing Aerodynamic performance Tandem formation

Seismic responses of an intensively constructed metro station-passageway-shaft structure system

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Frontiers of Structural and Civil Engineering 2024年第5期18卷 760-775页

作者： Ruohan li yong YUAN Hong CHEN Xinxing li Emilio BILOTTA Department of Geotechnical Engineering Tongji UniversityShanghai 200092China Department of Civil Architectural and Environmental EngineeringUniversity of Naples Federico IINaples 80125Italy State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shanghai Tunnel Engineering&Rail Transit Design and Research Institute Shanghai 200235China

Intensive construction methods offer benefits for metro station development,yet they present challenges for seismic design due to the spatially asymmetric configuration of passageway-shaft *** this study,a detailed numerical model of a station-passageway-shaft structure system built using intensive construction methods was developed and the deformation and damage modes under seismic loadings were *** results indicate that inconsistent deformation between the shaft and the station generates interaction through the connecting passageway,leading to damage near the opening of the station structure and both ends of the connecting passageway Damage is more severe under longitudinal *** with the opening plan that spans four segments,the opening plan that spans five segments exacerbates the overall degree of damage to the structure *** transverse excitation,the presence of interior structures intensifies the damage to the station and connecting passageway,while with such internal structure in place the impact is relatively minor under longitudinal *** with steel segments near the station opening can appreciably attenuate the *** contrast,introducing flexible joints at both ends of the connecting passageway intensifies the ***,reinforcement using steel segments emerges as an optimal seismic mitigation strategy.

关键词： earthquake intensive construction metro station numerical simulation

Physiological and pathological functions of circular RNAs in the nervous system

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Neural Regeneration Research 2024年第2期19卷 342-349页

作者： min Zhou Shi li Chuan Huang School of life Sciences Chongqing UniversityChongqingChina

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and *** play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 ***,the precise role of circRNAs in the nervous system has yet to be comprehensively *** this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and ***,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

关键词： Alzheimer’s disease amyotrophic lateral sclerosis brain development circRNAs neuropathic pain Parkinson’s disease

Probing the Kinematic Signatures of Planet Formation in the Gas Disk of MWC 480

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Research in Astronomy and Astrophysics 2024年第6期24卷 110-118页

作者： min Zhao Haochuan Yu Zhengxiang li Department of Astronomy Beijing Normal UniversityBeijing 100875China Sub-department of Astrophysics Department of PhysicsUniversity of OxfordOxfordOX13RHUK

The disk around MWC 480 has shown multiple substructures in both dust and gas observations,possibly suggesting ongoing planet formation in *** this paper,we explore the gas kinematics of the MWC 480 disk by analyzing the archival Atacama Large Millimeter/submillimeter Array observations of^(12)CO(J=2-1),^(13)CO(J=2-1),and C^(18)O(J=2-1).By modeling the line-of-sight velocities,inferred from the Doppler shifts of the emission lines,we are able to decompose the three-dimensional(3D)velocity field of the disk into rotational,radial,and vertical *** analysis reveals the presence of large-scale gas flows in the(r,z)***,we identify potential meridional flows across various heights as traced by all three CO isotopologues in the 80–120 au region,possibly associated with ongoing planet formation activities in this ***,we find upward flows near 200 au for all three CO isotopologues,which may point to the presence of disk winds.

关键词： protoplanetary disks planet-disk interactions planet-star interactions