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Microstructure and properties evolution of Nb-bearing medium Cr wear-resistant cast steel during heat treatment

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Journal of Iron and Steel Research International 2021年第6期28卷 739-751页

作者： Jia-cheng zhang tuo zhang Yi-tao Yang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

The effect of quenching temperature and cooling conditions on the microstructure and mechanical properties of a 0.2%Nb medium chromium wear-resistant cast steel was *** microstructure,carbides and volume fraction of retained austenite were characterized using the optical microscope,scanning electron microscope,transmission electron microscope and X-ray *** influence of heat treatment on hardness,impact toughness and tensile properties of test steel was *** can be observed that lath martensite can be obtained under the condition of air cooling and oil cooling upon austenitizing in the range of 900–1020℃.Total carbide content of 0.2–1.1 wt.%under air cooling is more than that under oil cooling due to the lower cooling ***6C5,M23C6 and M7C3 were found at lower austenitizing temperature,of which niobium carbide mostly located at grain boundaries,while chromium carbides were uniformly distributed in the matrix with the size of 20–50 *** chromium carbides are basically dissolved into the matrix in test steel austenitized at 1020°***,the negligible growth of prior austenite grain size is *** austenitized at 1020℃ and cooled in air+tempered at 200℃ has a best combination of hardness,plasticity and tensile strength due to fine grain size and more amount of retained *** this condition,the hardness is 58 HRC,the impact toughness is 22.92 J/cm^(2),and the tensile strength is 1136.9 MPa.

关键词： Wear-resistant steel Quenching temperature Cooling condition Carbide Retained austenite Strengthening Toughening

Ferroptosis in ischemic stroke:Animal models and mechanisms

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Zoological Research 2024年第6期45卷 1235-1248页

作者： Qing-zhang tuo Peng Lei Department of Geriatrics and State Key Laboratory of Biotherapy National Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengduSichuan 610041China Department of Neurology and State Key Laboratory of Biotherapy National Clinical Research Center for GeriatricsWest China HospitalSichuan UniversityChengduSichuan 610041China

Stroke is a major cause of death and disability worldwide,with the majority of cases resulting from ischemic events due to arterial *** therapeutic approaches focus on rapid reperfusion through intravenous thrombolysis and intravascular *** these interventions can mitigate long-term disability,reperfusion itself may induce neuronal *** exact mechanisms underlying neuronal damage following cerebral ischemia have yet to be *** research suggests that ferroptosis may play a significant role in post-ischemic neuronal death,which can be targeted to prevent neuronal *** review explores the three essential hallmarks of ferroptosis:the presence of redox-active iron,the peroxidation of polyunsaturated fatty acid-containing phospholipids,and the loss of lipid peroxide repair *** involvement of ferroptosis in neuronal injury following ischemic stroke is also explored,along with an overview of ferroptosis-associated changes in different ischemic stroke animal ***,recent therapeutic interventions targeting the ferroptosis pathway,as well as the opportunities,difficulties,and future directions of ferroptosis-targeted therapies in ischemic stroke,are discussed.

关键词： Ischemic stroke Ferroptosis Animal models Iron deposition Lipid peroxidation

Annealing temperature-dependent electrochemical properties of Aeroxide P25 TiO2 nanoparticles as anode material for lithium storage

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Progress in Natural Science:Materials International 2019年第6期29卷 679-684页

作者： tuo zhang Kaiming Li Jiahong Pan MOE Key Laboratory of Resources and Environmental Systems Optimization College of Environmental Science and Engineering North China Electric Power University Beijing Key Laboratory of Novel Thin-Film Solar Cells School of Renewable Energy North China Electric Power University

TiO2has been widely studied as an important electrode material for electrochemical energy *** its relationship between textural properties and electrochemical characteristics is essential to boosting its practical performances. Herein, Aeroxide P25 TiO2nanoparticles annealing at different temperatures(400–600 °C) were investigated as an anode material of lithium ion battery. Their evolution in crystal phase and microstructural characteristics were characterized by XRD and BET surface analysis, and their lithium storage properties in half-cells were evaluated by various electrochemical analyses, including cyclic voltammetry, cycling testing, and electrochemical impedance spectroscopy. It was found that the lithium storage properties were critically dependent on the size of TiO2anode materials. Pristine P25 initially exhibited the highest initial discharge specific capacity due to its smallest particle size; however, rapid capacity loss occurred during extended cycling. The annealing process was found to effectively enhance the cycling stability of TiO2although possessing a large particle size and smaller surface area. Typically, P400 showed the best performances in cycling stability, capacity retention ratio, and rate capability, which is mainly attributed to the synergistic effect of high crystallinity, reasonable particle size, and less internal resistance. This study provides an instance of optimizing the textural properties of metal oxides for advanced LIB anode material applications.

关键词： Lithium ion battery Aeroxide P25 TiO2 Electrochemical impedance spectroscopy X-ray diffraction(XRD) Cyclic voltammetry

Dual-polarized and real-time reconfigurable metasurface absorber with infrared-coded remote-control system

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Nano Research 2022年第8期15卷 7498-7505页

作者： Jiangyong Liu Yuping Duan tuo zhang Lingxi Huang Huifang Pang Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116085China

The reconfigurable metasurfaces which can regulate the microwave absorption performance at the sub wavelength scale provide a possibility to construct intelligent stealth ***,the existing reconfigurable-metasurface-based absorbers seriously limit the medium and long-distance regulation in practical application due to the complex circuit path and regulation ***,an infrared-coded dual-polarized metasurface absorber(IDMA)with remote-control mode was proposed,which realized the realtime dynamic regulation of the intensity and frequency range of absorption peaks by combining the infrared-coding remotecontrol technology with the active metasurface *** proposed remote-control system can switch the 8-bit binary coding sequences stored in the microcontroller unit(MCU)by an infrared transceiver,so as to regulate the state of active devices under X-and Y-polarizations,*** experimental results showed that the reflection/absorption responses can be regulated by switching different binary codes,and the reflection loss(RL)can be tuned below−7.5 dB(absorptivity over 82%)in wide range of 6.20–18 ***,the corresponding equivalent circuit model was established and the distributions of surface current and electric field were analyzed to elucidate the dynamic reconfigurable mechanism of the metasurface *** proposed IDMA,which combines intelligent electronic technology with active metasurface absorber,creatively realizes the remote control of active metasurface absorber and opens up a new way for the stealth technology of smart absorber in the future.

关键词： microwave absorption active metasurface reflection/absorption infrared-coded remote-control real-time dynamic control

Effect of yttrium addition on microstructure, mechanical and corrosion properties of 20Cr13 martensitic stainless steel

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Journal of Iron and Steel Research International 2020年第4期27卷 451-460页

作者： Qi-yu Zang Yang-fan Jin tuo zhang Yi-tao Yang School of Materials Science and Engineering Shanghai UniversityShanghai 200444China

The effects of rare-earth yttrium(Y)element on the microstructure,mechanical properties and corrosion properties of 20Cr13 martensitic stainless steel were investigated by optical microscopy,scanning electron microscopy and tensile *** experiments were carried out to study the effect of rare-earth element Y addition on corrosion *** results showed that the addition of 0.02 wt.%rare-earth yttrium to martensitic stainless steel could affect the microstructure transformation,and Ac3 temperature was obviously *** the stainless steel after heat treatment,there were more pro-eutectoid ferrite in the steel with 0.02 wt.%*** mechanical test results showed that the addition of 0.02 wt.%yttrium could significantly improve the tensile strength and elongation of the steel,which was related to the influence of yttrium element on inclusions in the test *** the quenching temperature of 0.02 wt.%yttrium steel increasing,the content of the ferrite in steel was affected and the corrosion resistance was remarkably improved.

关键词： Yttrium Martensitic stainless steel Mechanical property Microstructural characterization Corrosion

Behavior of Nb influence on structure and properties of 30Cr13 cast martensitic stainless steel

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Journal of Iron and Steel Research International 2019年第5期26卷 462-471页

作者： Yang-fan Jin tuo zhang Qi-yu Zang Yi-tao Yang School of Materials Science and Engineering Shanghai University Shanghai 200444 China

The microstructure, mechanical properties and corrosion resistance of 30Cr13 martensitic stainless steel (MSS) with different Nb contents were investigated by using the optical microscope, scanning electron microscope, X-ray diffractometer, HRC hardness measurement apparatus and tensile testing machine. Nb was found to retard the formation of austenite and promote the precipitation of carbides by calculating. The results showed that the addition of 0.2 wt.% Nb elements could improve the strength and corrosion resistance of 30Cr13 martensitic stainless steels while the reduction in toughness was less because of the inhibited effect on Cr-rich carbides precipitation by Nb addition. Specially, M23C6-type carbides almost disappeared in 0.6Nb-MSS. Moreover, the main existent form of Nb element was NbC and the strong carbide-forming ability of Nb element increased the quantity of carbides with the morphology changing from sphericaltype to chain-type. 0.2Nb-MSS shows excellent strength, adequate toughness and sufficient corrosion resistance for the application.

关键词： Niobium addition Martensitic stainless steel Microstructure Mechanical property Corrosion resistance

The pathological role of ferroptosis in ischemia/reperfusion-related injury

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Zoological Research 2020年第3期41卷 220-230页

作者： Hong-Fa Yan Qing-zhang tuo Qiao-Zhi Yin Peng Lei Department of Neurology and State Key Laboratory of Biotherapy West China HospitalSichuan Universityand Collaborative Center for BiotherapyChengduSichuan 610041China Chengdu University of Traditional Chinese Medicine ChengduSichuan 610041China

Ischemia/reperfusion(I/R) is a pathological process that occurs in numerous organs throughout the human body, and it is frequently associated with severe cellular damage and death. Recently it has emerged that ferroptosis, a new form of regulated cell death that is caused by iron-dependent lipid peroxidation, plays a significantly detrimental role in many I/R models. In this review, we aim to revise the pathological process of I/R and then explore the molecular pathogenesis of ferroptosis. Furthermore,we aim to evaluate the role that ferroptosis plays in I/R, providing evidence to support the targeting of ferroptosis in the I/R pathway may present as a therapeutic intervention to alleviate ischemia/reperfusion injury(IRI) associated cell damage and death.

关键词： Ischemia/reperfusion Ferroptosis Reactive oxygen species Lipid peroxidation Iron

Crystalline carbon nitride with in-plane built-in electric field accelerates carrier separation for excellent photocatalytic hydrogen evolution

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Chinese Chemical Letters 2024年第4期35卷 160-165页

作者： Wengao Zeng Yuchen Dong Xiaoyuan Ye Ziying zhang tuo zhang Xiangjiu Guan Liejin Guo International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

Achieving a high carrier migration efficiency by constructing built-in electric field is one of the promising approaches for promoting photocatalytic activity. Herein, we have designed a donor-acceptor(D-A) crystalline carbon nitride(APMCN) with 4-amino-2,6-dihydroxypyrimidine(AP) as electron donor, in which the pyrimidine ring was well embedded in the heptazine ring via hydrogen-bonding effect during hydrothermal process. The APMCN shows superior charge-transfer due to giant built-in electric field(5.94times higher than pristine carbon nitride), thereby exhibiting excellent photocatalytic H_(2) evolution rate(1350 μmol/h) with a high AQY(62.8%) at 400 nm. Mechanistic analysis based on detailed experimental investigation together with theoretical analysis reveals that the excellent photocatalytic activity is attributed to the promoted charge separation by the giant internal electric field originated from the D–A structure.

关键词： Crystalline carbon nitride Built-in electric field Donor-acceptor structure Photocatalysis Hydrogen production

Phase-field simulation of solidification dendritic segregation in Ti-45Al alloy

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China Foundry 2017年第3期14卷 184-187页

作者： Yu-tuo zhang Yun Chi Chun-qing Hu School of Materials Science and Engineering Shenyang Ligong University Shenyang 110159 China Liaoning Academy of Governance Shenyang 110161 China

The microstructures and mechanical properties of Ti Al alloys are directly linked to micro-segregation which cannot be avoided during solidification. So a thorough understanding of the micro-segregation should be a great help to further enhance the mechanical properties of the cast products. Theoretical analysis and experiments have been used to predict the micro-segregation, but it is very difficult to observe and determine the dendritic segregation in the micro region. Phase-field method has been employed for the simulation of dendritic growth. However, due to the complicated quasi-sub regular solution model for Ti-45Al(at.%) alloy, the classic phase-field models have difficulty to deal with the free energy. In this work, a phase-field model by linking thermodynamic calculation was used to simulate solidification dendritic segregation of Ti-45 Al alloy for Liquid→Liquid+β(Ti). The free energies of solid phase and liquid phase for Ti-45 Al alloy were calculated by Thermo-Calc and then coupled with the phase-field equations. The simulation results show the dendritic morphology and Al content variations between liquid and growing solid phase for Ti-45 Al alloy. With the growth of the β(Ti), dendritic segregation is formed in the liquid and solid phases due to the solute partitioning and rejection into the liquid. As a result, the dendrite arms are depleted of Al element, while the inter-dendrites are enriched. The dendritic tip growth velocity decreases with the progress of solidification, whereas the segregation ratio increases.

关键词：阶段地模型树枝状的分离 Ti-45Al 免费精力等温的团结 TP391.92 A