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Flow fields control for bubble refinement induced by electromagnetic fields

Journal of Iron and Steel Research(International) 2022年第4期29卷 575-587页

作者： Lian-yu Wang Ze-yi liu ming He Xiao-ming LIU Masamichi Sano Li-jia Zhao Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina

Large bubbles seriously reduce the efficiencies of the interactions between the bubbles and the molten steel,such as energy transfer,momentum transfer,mass transfer and chemical reaction.To reduce the size of the bubbles and increase the gas–liquid interface area,a novel non-intrusive method of bubble refinement was proposed,which only depends on the molten steel flow field controlled by the rotating electromagnetic field.The flow fields of the molten steel for bubble refinement were analyzed,and the corresponding bubble refinement was investigated.It was found that the molten steel formed obvious rotating turbulent flow for bubble refinement under the unidirectional rotating electromagnetic field.However,the large vortex in the center of the molten pool caused by the rotating flow made the bubbles aggregate and coalesce again,resulting in formation of larger bubbles and gas cavity.To suppress the central vortex formation and enhance the bubble refinement,the forward-reverse rotating electromagnetic field for bubble refinement was proposed.The irregular and chaotic flow occurred repeatedly because of alternating forward and reverse rotating in a short period,so that the turbulent kinetic energy and turbulent dissipation of the flow field always remained at a high level which favors bubble refinement.As a result,the bubble diameter can decrease by more than 50%compared to that without electromagnetic field.Furthermore,it is important that this non-intrusive kind of bubble refinement method completely avoids the introduction of non-metallic inclusions caused by intrusive configuration.

关键词： Bubble refinement Electromagnetic field Flow field Forward-reverse rotating Bubble Sauter

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Co_(3)O_(4)/stainless steel catalyst with synergistic effect of oxygen vacancies and phosphorus doping for overall water splitting

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Tungsten 2023年第1期5卷 100-108页

作者： xiao-xiao Li xiao-Chao liu Chao liu Jin-ming Zeng xiao-Peng Qi College of Rare Earth Jiangxi University of Science and TechnologyGanzhou 341000China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China

The electrolysis of water into hydrogen and oxygen provides an effective means of storing electrical energy indirectly.The current challenge is to design an optimal catalyst that exhibits low overpotentials,long-term stability,universal availability,and only uses inexpensive materials.Herein,a Co3O4nanoflower/stainless steel(P-Ov-CO_(3)O_(4)/SS) catalyst with both oxygen vacancies(Ovs) and phosphorus doping was perfectly prepared via a simple three-step method.The Ovs promoted charge transfer and accelerated the electrocatalysis,while P finely tuned the surface charge state.This resulted in numerous active sites for catalysis,and the synergistic effect of phosphorus doping and oxygen vacancies was finely demonstrated.The resultant electrocatalyst exhibited low hydrogen evolution overpotentials of 118 mV(-10 mA·cm^(-2)) and 242(-200 mA·cm^(-2)),as well as oxygen evolution overpotentials of 327 mV(100 mA·cm^(-2)) and 370 mV(200 mA·cm^(-2)),owing to the excellent synergistic effect of the Ovs and low-temperature phosphating.Moreover,P-Ov-Co_(3)O_(4)/SS//P-Ov-Co_(3)O_(4)/SS exhibited a low water splitting voltage of 1.681 V at 20 mA.cm-2.These findings will enable the synthesis of novel high-performance electrocatalysts for overall water splitting.

关键词： Oxygen vacancy Phosphorus doping P-Ov-Co_(3)O_(4)/SS Overall water splitting

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Improved Strategies for CRISPR-Cas12-based Nucleic Acids Detection

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Journal of Analysis and Testing 2022年第1期6卷 35-43页

作者： Miao Qiu xiao-ming Zhou Lei liu Institute for Brain Research and Rehabilitation South China Normal UniversityGuangzhou 510631China School of Life Sciences South China Normal UniversityGuangzhou 510631China

The COVID-19 pandemic has brought great challenges to traditional nucleic acid detection technology.Thus,it is urgent to develop a more simple and efficient nucleic acid detection technology.CRISPR-Cas12 has signal amplification ability,high sensitivity and high nucleic acid recognition specificity,so it is considered as a nucleic acid detection tool with broad development prospects and high application value.This review paper discusses recent advances in CRISPR-Cas12-based nucleic acid detection,with an emphasis on the new research methods and means to improve the nucleic acid detection capability of CRISPR-Cas12.Strategies for improving sensitivity,optimization of integrated detection,development of sim-plified detection mode and improvement of quantitative detection capabilities are included.Finally,the future development of CRISPR-Cas12-based nucleic acids detection is prospected.

关键词： CRISPR-Cas12 Nucleic acid detection Sensitivity Integrated detection Simplified detection mode Quantitative detection

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Automatic recognition and intelligent analysis of central shrinkage defects of continuous casting billets based on deep learning

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Journal of Iron and Steel Research(International) 2023年第5期30卷 937-948页

作者： Gong-hao Lian Qi-hao Sun Xiao-ming LIU Wei-miao Kong ming Lv Jian-jun Qi Yong liu Ben-ming Yuan Qiang Wang Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education) Northeastern UniversityShenyang 110819LiaoningChina State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina Shandong Iron and Steel Group Co. Ltd.Jinan 271105ShandongChina HBIS Material Technology Research Institude Shijiazhuang 050023HebeiChina Special Steel Business Department of Shandong Steel Laiwu Branch Jinan 271105ShandongChina

The internal quality inspection of the continuous casting billets is very important,and mis-inspection will seriously affect the subsequent production process.The UNet-VGG16 transfer learning model was used for semantic segmentation of the central shrinkage defects of the continuous casting billets.The automatic recognition accuracy of the central shrinkage defects of the continuous casting billets reaches more than 0.9.We use the minimum circumscribed rectangle to quantify the geometric dimensions such as length,width and area of the central shrinkage defects and use the threshold method to rate the central shrinkage defects of the continuous casting billets.The results show that all the testing images are rated correctly,and this method achieves the automatic recognition and intelligent analysis of the central shrinkage defects of the continuous casting billets.

关键词： Central shrinkage Deep learning Image segmentation Circumscribed rectangle Automatic recognition

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Advances in magnetic nanoparticle-based magnetic resonance imaging contrast agents

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Nano Research 2023年第11期16卷 12531-12542页

作者： Huan Zhang xiao Li liu Hai ming Fan Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education College of Chemistry and Materials ScienceNorthwest UniversityXi’an 710127China Department of Radiology Zhuhai People’s Hospital(Zhuhai Hospital Affiliated with Jinan University)Zhuhai 519000China Laboratory of Resource Biology and Biotechnology in Western China Ministry of EducationProvincial Key Laboratory of Biotechnology of Shaanxi ProvinceNorthwest UniversityXi’an 710069China Institute of Regenerative and Reconstructive Medicine Med-X InstituteFirst Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710049China National Local Joint Engineering Research Center for Precision Surgery&Regenerative Medicine Shaanxi Provincial Center for Regenerative Medicine and Surgical EngineeringFirst Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China

Magnetic resonance imaging(MRI)has revolutionized medical imaging diagnostics with the advantages of non-invasive nature,absence of ionizing radiation,unrestricted penetration depth,high-resolution imaging of soft tissues,organs and blood vessels,and multi-parameter and multi-sequence imaging.Contrast agents(CAs)are crucial for enhancing image quality,detecting molecular-level changes,and providing comprehensive diagnostic information in contrast enhanced MRI.However,the performance of clinical Gd-based CAs represents a limitation to the improvement of MRI sensitivity,specificity,and versatility,thereby impeding the achievement of satisfactory imaging outcomes.In recent years,the development of magnetic nanoparticle-based CAs has emerged as a promising avenue to enhance the capabilities of MRI.Here,we review the advances in magnetic nanoparticle-based MRI CAs,including blood pool CAs,biochemically-targeted CAs,stimulus-responsive CAs,and ultra-high field MRI CAs,as well as the use of CAs for cell labeling and tracking.Additionally,we offer insights into the future prospects and challenges associated with the integration of these nanoparticles into clinical practice.

关键词： magnetic resonance imaging magnetic nanoparticle blood pool contrast agents biochemically-targeted contrast agents stimulus-responsive contrast agents

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Composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling

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Journal of Iron and Steel Research(International) 2022年第4期29卷 552-562页

作者： Nan liu Gong Cheng Li-feng Zhang Wen Yang Ying Ren Guo-cheng Wang Xiao-ming LIU School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China Steelmaking Plant Baotou Steel Union Co.Ltd.Baotou 014010Inner MongoliaChina Engineering Technology Co. Ltd.WISDRI Engineering and Research Incorporation LimitedWuhan 430223HubeiChina School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China School of Materials and Metallurgy University of Science and Technology LiaoningAnshan 114051LiaoningChina

The composition evolution and deformation of different non-metallic inclusions in a bearing steel during hot rolling were investigated by the automatic detection and the improved non-aqueous electrolysis method.Manganese sulfide,MnS–TiN,and liquid CaO–Al_(2)O_(3) inclusions were elongated while TiN and MgO-Al_(2)O_(3) were fractured during hot rolling.The CaS–MnS phase in the MgO–Al_(2)O_(3)–CaS–MnS inclusion was separated from the inclusion,leading to the formation of CaS–MnS type clusters.Meanwhile,the CaS and MnS contents in oxide-containing inclusions decreased while the MgO and Al_(2)O_(3) contents increased after hot rolling.The deformability of different inclusions in the bearing steel was quantitatively compared and discussed.

关键词： Bearing steel Hot rolling Composition evolution Deformability Inclusion

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Rare earth element geochemistry in soils along arid and semiarid grasslands in northern China

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Ecological Processes 2022年第1期11卷 386-399页

作者： Yi‑Wen Cao xiao‑ming liu Chao Wang Edith Bai Nanping Wu CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China Department of Earth Marine and Environmental SciencesUniversity of North Carolina‑Chapel HillChapel HillNC 27515USA Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains School of Geographical SciencesNortheast Normal UniversityChangchun 130024China Institute of Deep‑Sea Science and Engineering Chinese Academy of SciencesSanya 572000China

Background:Rare earth elements(REE)are a group of trace elements that behave geochemically coherently.REE fractionation patterns normalized to reference materials provide a powerful tool for documenting pedogenesis.Insoil processes are particularly difficult to illustrate with respect to contemporary and past climate conditions.In this study,we characterize the rare earth element(REE)contents in bulk soils and respective geochemical fractions(e.g.,exchangeable,carbonate‑bound,reducible,and oxidizable fractions)and to decipher the relationships between REE geochemistry components and climatic factors across a large‑scale northern China transect(NCT).Results:Across the NCT,bulk REE concentrations ranged from 55.2 to 241.1μg g^(−1)with a main portion in the residual fraction(49–79%),followed by oxidizable fraction(2–40%),reducible fraction(3–22%),carbonate‑bound fraction(0.1–16%),and negligible exchangeable fraction.The REE contents of geochemical components(carbonate‑bound,reducible,and oxidizable)in topsoils correlated to climate factors(mean annual precipitation,mean annual temperature,potential evaporation,and aridity index(AI)).The normalized abundances to the upper continental crust(UCC)composition show that the middle REE was generally enriched than the light REE and heavy REE in topsoils along the transect.The overall UCC‑normalized bulk REE patterns in topsoils and subsoils were similar,characterized by weak negative Ce anomalies and positive Eu anomalies.Conclusions:Our data in topsoils and depth profiles collectively suggest that cycling of REE was primarily regulated by abiotic processes in area with AI0.3.The similar UCC normalized patterns in topsoils suggest that the REE was originated from a common source with limited influences from other sources(e.g.,atmospheric dusts and anthropogenic contribu‑tions).Our results to some extent provide evidence for climatic influence REE distribution patterns bo

关键词： Rare earth elements Soil Grassland Northern China Aridity index

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Distributed event-triggered adaptive control for second-order nonlinear uncertain multi-agent systems

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Chinese Journal of Aeronautics 2021年第10期34卷 237-247页

作者： ming xiao Zhitao liu Hongye SU The State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang UniversityHangzhou 310027China

In this paper,the event-triggered consensus control problem for nonlinear uncertain multi-agent systems subject to unknown parameters and external disturbances is considered.The dynamics of subsystems are second-order with similar structures,and the nodes are connected by undirected graphs.The event-triggered mechanisms are not only utilized in the transmission of information from the controllers to the actuators,and from the sensors to the controllers within each agent,but also in the communication between agents.Based on the adaptive backstepping method,extra estimators are introduced to handle the unknown parameters,and the measurement errors that occur during the event-triggered communication are well handled by designing compensating terms for the control signals.The presented distributed event-triggered adaptive control laws can guarantee the boundness of the consensus tracking errors and the Zeno behavior is avoided.Meanwhile,the update frequency of the controllers and the load of communication burden are vastly reduced.The obtained control protocol is further applied to a multi-input multi-output second-order nonlinear multi-agent system,and the simulation results show the effectiveness and advantages of our proposed method.

关键词： Adaptive distributed control structure Event-triggered control Multi-agent systems Second-order nonlinear models

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Experimental Study on Interference Effect of Three Risers Arranged in Tandem with Variable Spacing Ratios

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China Ocean Engineering 2023年第3期37卷 408-419页

作者： ZHANG Peng liu Li-hua liu ming REN xiao-hui WANG Yu School of Civil Engineering Qingdao University of TechnologyQingdao 266520China College of Civil Engineering and Architecture Shandong University of Science and TechnologyQingdao 266590China Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Qingdao 266590China School of Petroleum Engineering China University of Petroleum(East China)Qingdao 266580China

Taking the three-riser group arranged in tandem as the research subject,an experimental study was carried out on the risers arranged in tandem.The purpose is to explore the sensitivity of the dynamic response of each riser to spacing ratio and reveal the physical mechanism of riser groups under the interference effect.The spacing ratios of the adj acent risers are 4.0,5.0,6.0,and 8.0.At the spacing between the risers of 4.0D,the strong feedback effect increases the cross-flow(CF) displacement amplitude of the upstream riser.The shielding effect is the key factor affecting the interference effect on the midstream and downstream risers.At low reduced velocities,the shielding area initially appears,the displacement amplitude of the midstream and downstream risers varies greatly,the vibration of the two risers is still dominated by the first-order mode,and the transition between adjacent vibration modes is restrained.The multi-frequency superposition phenomenon is very significant at high reduced velocities.The most sensitive interference spacing under the test conditions is obtained.Due to the separation of the incoming flow and the double shielding effect of the upstream and midstream risers,the regular vortex-induced vibration in the wake area of the downstream riser is broken,and the vibration in the two directions is weakened.In general,the interference effect is more significant for the CF vibration of the three-riser groups than the in-line(IL) vibration.

关键词： three-riser group tandem arrangement vortex-induced vibration wake interference variable spacing ratios

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The roles of microRNAs in regulating root formation and growth in plants

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Journal of Integrative Agriculture 2022年第4期21卷 901-916页

作者： YAN xiao-xiao liu Xiang-yang CUI Hong ZHAO ming-qin College of Tobacco Science Henan Agricultural University/National Tobacco Cultivation and Physiology and Biochemistry Research Center/Key Laboratory for Tobacco Cultivation of Tobacco IndustryZhengzhou 450002P.R.China

MicroRNAs(miRNAs) are small(ca. 20-24 nucleotides) non-coding RNAs that have recently been recognized as key post-transcriptional modulators of gene expression;and they are involved in many biological processes in plants, such as root growth and development. The miRNAs regulate root elongation, lateral root(LR) formation and adventitious root(AR) development in response to hormone signaling, nutrient uptake and biotic/abiotic stress. This review provides multiple perspectives on the involvement of miRNAs in regulating root growth and development in plants. We also discuss several crucial mechanisms of miRNAs, their relationships with transcription factors and the target gene-mediated hormone signaling interactions in the regulation of root growth and development.

关键词： microRNAs adventitious root lateral root primary root

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