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Journal of Iron and Steel Research International 2024年第4期31卷 945-955页

作者： Yuan Zhang Xiang Liu chang-jun Wang chang Liu School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093YunnanChina Central Iron&Steel Research Institute Co. Ltd.Beijing 100081China

Ph13-8Mo stainless steel powder with high sphericity and well fluidity was prepared by the plasma rotating electrode *** formed parts with ultra-high purity were manufactured by selective laser *** tensile and impact mechanical properties of the printed parts under three heat treatment regimes were compared to those without heat *** microstructure,grain orientation and phase composition were characterized by electron-backscatter diffraction,X-ray diffraction and transmission electron *** characterization results reveal that the addition of heat treatment makes the grains enlarge,and after different heat treatments,the average grain size from 1.51μm in the printed state increases to 2.78,3.09 and 2.06μm,*** formed parts are mainly composed of martensite and retained ***,the NiAl and M23C precipitates form,which are the major strengthening phases of Ph13-8Mo stainless *** optimal heat treatment process is 925℃×1 h water cooling(WC)+0℃×2 h air cooling(AC)+540℃×4 h *** this heat treatment process,Ph13-8Mo formed parts have the optimal comprehensive mechanical properties:the tensile strength,yield strength and impact energy KU2 are 1492 MPa,1432 MPa and 63 J,*** strengthening and toughening via heat treatment are mainly attributed to dislocation strengthening,the formation of NiAl and M23Co precipitates and the change of volume fraction of the retained austenite.

关键词： high-strength stainless steel-Selective laser melting-heat treatment Microstructure Mechanical property

Effect of tubastatin A on NLRP3 inflammasome activation in macrophages under hypoxia/ reoxygenation conditions

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World Journal of Emergency Medicine 2024年第4期15卷 289-296页

作者： hao Li chang Liu Ying Cui Panpan chang Wei Chong Department of Emergency Medicine the First Hospital of China Medical UniversityShenyang 110001China Trauma Medicine Center Peking University People's HospitalBeijing 100871China Key Laboratory of Trauma and Neural Regeneration Peking UniversityBeijing 100871China National Center for Trauma Medicine of China Beijing 100871China

BACKGROUND:There are currently no effective drugs to mitigate the ischemia/reperfusion injury caused by fluid resuscitation after hemorrhagic shock(hS).The aim of this study was to explore the potential of the histone deacetylase 6(hDAC6)-specific inhibitor tubastatin A(TubA)to suppress nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)inflammasome activation in macrophages under hypoxia/reoxygenation(h/R)***:The viability of RAW264.7 cells subjected to h/R after treatment with different concentrations of TubA was assessed using a cell-counting kit-8(CCK8)***,2.5μmol/L TubA was used with RAW264.7 cells under h/R ***264.7 cells were divided into three groups,namely the control,h/R,and TubA *** levels of reactive oxygen species(ROS)in the cells were detected using fluorescence *** protein expression of hDAC6,heat shock protein 90(hsp90),inducible nitric oxide synthase(iNOS),NLRP3,gasdermin-D(GSDMD),Caspase-1,GSDMD-N,and Caspase-1 p20 was detected by western *** levels of interleukin-1β(IL-1β)and IL-18 in the supernatants were detected using enzyme-linked immunosorbent assay(ELISA).RESULTS:hDAC6,hsp90,and iNOS expression levels were significantly higher(Phe h/R group than in the control group,but lower in the TubA group than in the h/R group(Phen comparing the h/R group to the control group,ROS levels were significantly higher(Pficantly reduced in the TubA group(Phe h/R group had higher NLRP3,GSDMD,Caspase-1,GSDMD-N,and Caspase-1 p20 expression levels than the control group(Phowever,the TubA group had significantly lower expression levels than the h/R group(Phe supernatants were significantly higher in the h/R group compared to the control group(Pficantly lower in the TubA group compared to the h/R group(Phibited the expression of hDAC6,hsp90,and iNOS in macrophages

关键词： hemorrhagic shock hypoxia/reoxygenation Macrophage NLRP3 Tubastatin A

Event-triggered h_(∞) consensus control for input-constrained multi-agent systems via reinforcement learning

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Control Theory and Technology 2024年第1期22卷 25-38页

作者： Jinxuan Zhang chang-E Ren College of Information Engineering Capital Normal UniversityBeijing100089China

This article presents an event-triggered h_(∞) consensus control scheme using reinforcement learning (RL) for nonlinear second-order multi-agent systems (MASs) with control constraints. first, considering control constraints, the constrained h_(∞) consensus problem is transformed into a multi-player zero-sum game with non-quadratic performance functions. Then, an event-triggered control method is presented to conserve communication resources and a new triggering condition is developed for each agent to make the triggering threshold independent of the disturbance attenuation level. To derive the optimal controller that can minimize the cost function in the case of worst disturbance, a constrained hamilton–Jacobi–Bellman (hJB) equation is defined. Since it is difficult to solve analytically due to its strongly non-linearity, reinforcement learning (RL) is implemented to obtain the optimal controller. In specific, the optimal performance function and the worst-case disturbance are approximated by a time-triggered critic network;meanwhile, the optimal controller is approximated by event-triggered actor network. After that, Lyapunov analysis is utilized to prove the uniformly ultimately bounded (UUB) stability of the system and that the network weight errors are UUB. finally, a simulation example is utilized to demonstrate the effectiveness of the control strategy provided.

关键词： h_(∞)optimal control Input constrains Multi-agent systems(MASs) Reinforcement learning(RL)

Numerical analysis of a projecting wall type oscillating water column(PW-OWC)wave energy converter in regular waves

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Journal of hydrodynamics 2024年第3期36卷 479-491页

作者： Lei Tan Ruiyuan chang Tomoki Ikoma Department of Oceanic Architecture and Engineering College of Science and TechnologyNihon UniversityChibaJapan

Oscillating water column(OWC)based wave energy absorption devices are classic which have been widely used for harnessing ocean wave *** paper presents a numerical study on a projecting wall(PW)type OWC wave energy converter in regular *** computational fluid dynamics(CfD)modelling of a stationary floating PW-OWC model in a three-dimensional wave flume is achieved by the software *** analyses are carried out based on CfD simulations and the linear potential flow solutions with modifications to account for turbine-induced *** present numerical solutions are validated against our previous experimental *** is found that both the CfD and modified linear potential flow predictions are in reasonably good agreements with the experimental data in the first order results of OWC and air pressure *** the nonlinear responses are included in the result,the modified linear potential flow solution is found to slightly under-estimate the wave energy conversion performance at long *** the airflows above and below the chamber orifice,the CfD results suggest that they are almost unidirectional,oscillating in not only the base frequency but also subharmonic and ultraharmonic *** evolution of the OWC responses during an entire period and the phase analysis based on CfD simulations are *** phase results provide the crucial evidence to the reasonability of the physics-based modification of the potential flow model in modelling of *** present results and analysis are expected to be beneficial to the understanding on the physical mechanism of OWCs and the design of phase control strategies.

关键词： Computational fluid dynamics(CfD)simulation hydrodynamic analysis oscillating water column(OWC)damping orifice airflow phase difference

An Experimental Study on Response and Control of a flapping-Wing Aerial Robot Under Wind Gusts

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Journal of Bionic Engineering 2024年第1期21卷 209-223页

作者： Kazuki Shimura hikaru Aono chang-kwon Kang Graduate School of Science and Technology Shinshu University3-15-1 TokidaUedaNagano 3868567Japan Department of Mechanical Engineering and Robotics 3-15-1 TokidaUedaNagano 3868567Japan Department of Mechanical and Aerospace Engineering University of Alabama in HuntsvilleTechnology Hall N266HuntsvilleAL35899USA

Bioinspired flapping-wing micro-air-vehicles(fWMAVs)have the potential to be useful aerial tools for gathering information in various *** recent advancements in manufacturing technologies and better understanding of aerodynamic mechanisms behind of the flapping flight,outdoor flights have become a ***,to fully realize the potential of fWMAVs,further improvements are necessary,particularly in terms of stability and robustness under gusty *** this study,the response and control of a tailless two-winged fWMAV under the wind gusts are *** experiments are conducted with a one-degree-of-freedom gimbal to focus on effects of wind gusts on the rotational motion of the ***-derivative and sliding-mode controls are adopted for the attitude *** present that the body angles changed in time and reached approximately 50°at the maximum due to the wing *** sliding-mode controller can more effectively control the rotational angle in the presence of disturbances and both the wing speed and changes in wind speed have an impact on the effectiveness of attitude *** results contribute to the development of of tailless two-winged,single-motor driven fWMAVs in terms of the design of attitude controller and testing apparatus.

关键词： flapping-wing micro-air vehicles Sliding-mode control Pitch and roll angle-Wind gus

Effect of Mo on microstructural characteristics and coarsening kinetics of γ' precipitates in Co–Al–W–Ta–Ti alloys

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Journal of Materials Science & Technology 2018年第5期34卷 799-805页

作者： h.J.Zhou f.Xue h.chang Q.feng State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing National Center for Materials Service Safety University of Science and Technology Beijing

The solvus temperature,volume fraction,coarsening behavior of γ＇ precipitates and the partitioning behavior of alloying elements as well as lattice misfit of γ/γ＇ phases influence the creep behavior of Ni-and Co-base ***,few investigations about the microstructural characteristics and the coarsening behavior of γ＇ precipitates were reported in multicomponent novel Co-base superalloys during thermal *** alloys containing different contents of molybdenum and tungsten have been investigated to explore the effect of molybdenum on γ＇ solvus temperature,γ ＋γ＇ microstructure and γ＇ coarsening in Co–Al–W–Ta–Ti-base *** results showed that the γ＇ solvus temperature decreases with the addition of *** addition reduces the Y＇ volume fractions after aging above 1000℃,but results in negligible influence on the γ＇ volume fractions aging at 900℃.Meanwhile,γ＇ coarsening is controlled by diffusion in experimental alloys after aging at 900℃ and 1000℃,and the kinetics of Y＇growth in experimental alloys are consistent with the predictions of LSW theory.

关键词： Cobalt alloys Molybdenum Coarsening Microstructure

Population genomic data reveal low genetic diversity,divergence and local adaptation among threatened Reeves's Pheasant(Syrmaticus reevesii)

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Avian Research 2024年第1期15卷 1-11页

作者： Qi Lu Pengcheng Wang Jiang chang De Chen Shenghan Gao Jacob hoglund Zhengwang Zhang Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering College of Life SciencesBeijing Normal UniversityBeijing100875China Jiangsu Key Laboratory for Biodiversity and Biotechnology College of Life SciencesNanjing Normal UniversityNanjing210023China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing100012China State Key Laboratory of Microbial Resources Institute of MicrobiologyChinese Academy of SciencesBeijing100101China Department of Ecology and Genetics Animal EcologyUppsala UniversityUppsalaSweden

Population genomic data could provide valuable information for conservation efforts;however,limited studies have been conducted to investigate the genetic status of threatened ***’s Pheasant(Syrmaticus reevesii)is facing population decline,attributed to increases in habitat *** is a knowledge gap in understanding the genomic status and genetic basis underlying the local adaptation of this threatened ***,we used population genomic data to assess population structure,genetic diversity,inbreeding patterns,and genetic ***,we identified candidate genes linked with adaptation across the current distribution of Reeves’s *** present study assembled the first de novo genome sequence of Reeves’s Pheasant and annotated 19,458 *** also sequenced 30 individuals from three populations(Dabie Mountain,Shennongjia,Qinling Mountain)and found that there was clear population structure among those *** comparing with other threatened species,we found that Reeves’s Pheasants have low genetic *** of homozygosity suggest that the Shennongjia population has experienced serious *** demographic history results indicated that three populations experienced several declines during the glacial *** adaptative analysis among the populations identified 241 candidate genes under directional *** are involved in a large variety of processes,including the immune response and *** results suggest that the three populations should be considered as three different conservation *** current study provides genetic evidence for conserving the threatened Reeves’s Pheasant and provides genomic resources for global biodiversity management.

关键词： Conservation genetics Local adaptation Pheasant Whole-genome sequencing

Pt nanodendrites with a PtIr alloy surface structure exhibit excellent stability toward acidic hydrogen evolution reaction

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Nano Research 2024年第6期17卷 4844-4849页

作者： chang Liu Zongnan Wei Minna Cao Rong Cao State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China University of Chinese Academy of Sciences Beijing 100049China fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China

The development of effective and stable electrocatalysts for the hydrogen evolution reaction(hER)in acidic electrolytes is a significant *** this work,homogeneous Pt nanodendrites(Pt NDs)with a PtIr shell were successfully synthesized by a two-step wet chemical *** open three-dimensional(3D)dendritic structure exhibited exceptional electrocatalytic characteristics,exposing as many active sites as ***,by alloying Ir with Pt on the surface,catalytic activity was greatly enhanced while ensuring extremely high *** surface-enriched platinum nanodendritic catalysts(Pt@PtIr NDs)outperformed the control samples and the commercial *** acidic hER test,Pt@PtIr NDs had a lower overpotential(22 mV)than Pt NDs(26 mV)and commercial Pt/C(31 mV)at 10 mA/cm^(2),and the activity of Pt@PtIr NDs remained consistent even after undergoing a continuous durability test for at least 168 h,which was much superior to the performance of commercial Pt/C(10 h)under identical test *** study revealed that the application of 3D Pt dendritic metal alloys may offer a chance for the development of enhanced electrocatalysts in acidic hER.

关键词： Pt nanodendrites iridium high stability hydrogen evolution reaction alloy

A methodology for laser tool setters calibration and its precise mathematical model

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Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao fANG Zixi fANG Ze Zhong ChEN Zhiyong chang School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools Mathematical model Calibration method Laser tool sette

Microstructures and mechanical properties of laser-directed energy deposited CrCoNi medium-entropy alloy

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Rare Metals 2024年第7期43卷 3286-3300页

作者： Wen-Jie Zhao chang-Yu Liu Peng-Cheng Che Zhi-Liang Ning hong-Bo fan Jian-fei Sun Yong-Jiang huang Alfonso h.W.Ngan National Key Laboratory for Precision hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001China Department of Mechanical Engineering The University of Hong KongHong Kong 999077China

The distinctive intrinsic heat treatment(IhT)originating from cyclic reheating in the laser-directed energy deposition(LDED) has attracted growing attention in recent *** this investigation,simulations and experimental characterizations were performed to examine the impact of IhT on the micros true ture and mechanical properties of LDED-fabricated CrCoNi medium-entropy alloy(MEA).The results show that the intensity of the IhT is proportional to the utilized laser energy density(LED).As the LED increased,significant dynamic recrystallization and grain refinement occurred within the alloy due to the enhanced intensity of ***,the high LED leads to severe hot cracking within the as-built MEA,resulting in inferior *** decreasing LED,the hot cracking was effectively ***,low LED weakened the intensity of IhT and consequently inhibited kinetic conditions of dynamic recrystallization,resulting in a heterogeneous grain structure characterized by multi-scale-sized *** structure provides significant hetero-deformation-induced hardening during plastic deformation,enabling the alloy to have a sustainable work-hardening *** expect that this work will have implications in taking full advantage of the unique IhT of the LDED process to fabricate ME As with excellent metallurgical quality and mechanical performance.

关键词： Intrinsic heat treatment Laser-directed energy deposition CrCoNi MEA Dynamic recrystallization heterogeneous grain structure