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Effects of Environmental Factors on Corrosion Behavior of E690 Steel in Simulated Marine Environment

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 678-694页

作者： Jingjing Peng Jing Liu Shen Zhang Zhihui wang Xian Zhang kaiming Wu Collaborative Innovation Center for Advanced Steels Hubei Province Key Laboratory of Systems Science in Metallurgical ProcessThe State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan430081China

The effects of hydrostatic pressure, dissolved oxygen, temperature and flow velocity, and their interaction on the corrosion rates of E690 high-strength steel (HSS) in simulated marine environments were studied using response surface methodology. The results show that the flow velocity exerts the most significant influence on the corrosion rate of E690 HSS. Consequently, the corrosion behavior of E690 HSS under varying flow velocities were analyzed profoundly from initial pitting corrosion to long-term corrosion properties. The results indicate that the flow state facilitates the mass transfer and enhances the adsorption tendency of Cl− by enhancing the electrochemical activity of the steel surface. These factors accelerate the electrochemical reactions, resulting in increased pitting density, depth and the long-term corrosion rates in dynamic seawater environments.

关键词： E690 steel Simulated marine environment Corrosion behavior Flow velocity Response surface methodology(RSM)

The chemical environment and structural ordering in liquid Mg-Y-Zn system:An ab-initio molecular dynamics investigation of melt for the formation mechanism of LPSO structure

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Journal of Magnesium and Alloys 2024年第2期12卷 815-824页

作者： Tangpeng Ma Jin wang kaiming Cheng Chengwei Zhan Jixue Zhou Jingyu Qin Guochen Zhao Xinfang Zhang Shandong Provincial Key Laboratory of High Strength Lightweight Metallic Materials Advanced Materials InstituteQilu University of Technology(Shandong Academy of Sciences)Jinan 250014China Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJinan 250061China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

In an effort to clarify the formation mechanism of LPSO structure in Mg-Y-Zn alloy,the chemical environment and structural ordering in liquid Mg-rich Mg-Y-Zn system are investigated with the aid of ab-initio molecular dynamics simulation.In liquid Mg-rich Mg-Y alloys,the strong Mg-Y interaction is determined,which promotes the formation of fivefold symmetric local structure.For Mg-Zn alloys,the weak Mg-Zn interaction results in the fivefold symmetry weakening in the liquid structure.Due to the coexistence of Y and Zn,the strong attractive interaction is introduced in liquid Mg-Y-Zn ternary alloy,and contributes to the clustering of Mg,Y,Zn launched from Zn.What is more,the distribution of local structures becomes closer to that in pure Mg compared with that in binary Mg-Y and Mg-Zn alloys.These results should relate to the origins of the Y/Zn segregation zone and close-packed stacking mode in LPSO structure,which provides a new insight into the formation mechanism of LPSO structure at atomic level.

关键词： Mg-Y-Zn Chemical environment Structural ordering ab-initio molecular dynamics

Oligomeric donor with appropriate crystallinity for organic solar cells

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Chinese Chemical Letters 2024年第2期35卷 289-294页

作者： kaiming Yang Min Lv Yanhong Chang Kun Lu Zhixiang Wei CAS Key Laboratory of Nanosystem and Hierarchical Fabrication CAS Center for Excellence in NanoscienceNational Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Department of Environmental Science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Resource Treatment of Typical Industrial Pollutants Beijing 100083China

Improving the performance of all-small-molecule organic solar cells(ASM-OSCs)largely depends on the design and application of novel donors with appropriate crystallinity.Extending molecular conjugation is an effective method for regulating molecular stacking and crystallinity.In this work,we successfully designed and synthesized two novel acceptor-donor-donor-donor-acceptor(A-D-D-D-A)type oligomeric donors with three dithieno[2,3-d:2′,3′-d′]benzo[1,2-b:4,5-b']dithiophene(DTBDT)as the central unit,named as 3DTBDT-Cl and 3DTBDT,depending on with and without chlorine substitution on the thiophene side chains.We found that the introduction of chlorine atoms makes the blend films display stronger crystallinity but with large-scale phase separation morphology and more defects,which eventually leads to a power conversion efficiency(PCE)of only 10.83%,whereas the blend films based 3DTBDT with appropriate crystallinity achieved 13.74%PCE.Compared with 3DTBDT-Cl/L8-BO,the 3DTBDT/L8-BO films exhibited a nanoscale bi-continuous interpenetrating network morphology with a smaller domain size and more suitable crystallinity,which guarantees the corresponding devices obtained more efficient exciton dissociation,efficient charge transport,reduced bimolecular recombination,and performed more balanced carrier mobility.These results demonstrated that regulating the crystallinity of oligomeric donors to obtain the desired phase separation morphology in the blend films could facilitate further improving the performance of ASM-OSCs.

关键词： Linked donor unit Oligomeric donors Crystallinity regulation Organic solar cells

High-density triple-phase contact points for enhanced photocatalytic CO_(2) reduction to methanol

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Chinese Chemical Letters 2024年第2期35卷 252-256页

作者： Hanwen Jian kaiming Deng Tongyu wang Chengxi Huang Fang Wu Hailing Huo Bo Ouyang Xuan Liu Jingjing Ma Erjun Kan Ang Li MIIT Key Laboratory of Semiconductor Microstructure and Quantum Sensing School of ScienceNanjing University of Science and TechnologyNanjing 210094China College of Information Science and Technology Nanjing Forestry UniversityNanjing 210037China State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering Ningxia UniversityYinchuan 750021China

The efficiency of photocatalytic CO_(2) reduction reaction(PCRR)is restricted by the low solubility and mobility of CO_(2) in water,poor CO_(2) adsorption capacity of catalyst,and competition with hydrogen evolution reaction(HER).Recently,hydrophobic modification of the catalyst surface has been proposed as a potential solution to induce the formation of triple-phase contact points(TPCPs)of CO_(2)(gas phase),H_(2) O(liquid phase),and catalysts(solid phase)near the surface of the catalyst,enabling direct delivery of highly concentrated CO_(2) molecules to the active reaction sites,resulting in higher CO_(2) and lower H+surface concentrations.The TPCPs thus act as the ideal reaction points with enhanced PCRR and suppressed HER.However,the initial synthesis of triple-phase photocatalysts tends to possess a lower bulk density of TPCPs due to the simple structure leading to limited active points and CO_(2) adsorption sites.Here,based on constructing a hydrophobic hierarchical porous TiO_(2)(o-HPT)with interconnected macropores and mesopores structure,we have significantly increased the density of TPCPs in a unit volume of the photocatalyst.Compared with hydrophobic macroporous TiO_(2)(o-MacPT)or mesoporous TiO_(2)(o-MesPT),the o-HPT with increased TPCP density leads to enhanced photoactivity,enabling a high methanol production rate with 1111.5μmol g^(−1) h^(−1) from PCRR.These results emphasize the significance of high-density TPCPs design and propose a potential path for developing efficient PCRR systems.

关键词： Photocatalysis CO_(2)reduction reaction Photocatalyst Triple-phase contact points Methanol

An unusual anterior mitral leaflet perforation in a patient with no infective endocarditis:a case report

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Emergency and Critical Care Medicine 2024年第1期4卷 39-41页

作者： kaiming Wei Yu Yao Chuanzhen Liu Yuan Cao Department of Cardiovascular Surgery Qilu Hospital of Shandong UniversityJinanShandongChina Department of Emergency Medicine Qilu Hospital of Shandong UniversityJinanShandongChina National Key Laboratory for Innovation and Transformation of Luobing Theory The Key Laboratory of Cardiovascular Remodeling and Function ResearchChinese Ministry of EducationChinese National Health Commission and Chinese Academy of Medical SciencesDepartment of CardiologyQilu Hospital of Shandong UniversityJinanShandongChina.

Background:Mitral valve perforation refers to the occurrence of cracks or openings in the structure of the mitral valve,allowing blood to escape through these gaps.Typically,this is caused by infective endocarditis and the most common site is the anterior leaflet.However,it is crucial to explore other potential causes of valve damage,particularly when conventional risk factors are not apparent.Case presentation:We present a case of a middle-aged male patient who developed mitral valve perforation because of aortic valve regurgitation in the absence of infective endocarditis.Conclusion:Exploring such rare cases contributes to a deeper understanding of valvular diseases and enhances clinical decision making for effective management.

关键词： Anterior mitral leaflet Aortic valve Case report Perforation Prolapse Regurgitation

One step hot-pressing method for hybrid Li metal anode of solid-state lithium metal batteries

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Journal of Materials Science & Technology 2023年第22期153卷 32-40页

作者： kaiming wang Yifei Chen Liang Zhang Qihang Zhang Zhi Cheng Yining Su Fei Shen Xiaogang Han State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049China School of Future Technology Xi’an Jiaotong UniversityXi’an 710049China Key Laboratory of Smart Grid of Shaanxi Province Xi’anXi’an 710049China National Innovation Platform(Center)for Industry-Education Integration of Energy Storage Technology Xi’an 710049China

Safety issues induced by infinite anode volume change and uncontrolled lithium(Li)dendrite growth have become the biggest obstacle to the practical application of Li metal batteries.In addition,the tra-ditional rolling method makes it difficult to manufacture thin Li foil with high mechanical strength and low Li content.Herein,a three-dimensional(3D)lithophilic carbon paper/copper(Cu)current collector hybrid anode with ultra-low Li metal content is prepared by a hot-pressing method.The highly re-versible and stable lithiophilic layer LiC_(x) formed in situ by heating/pressing treatment provides abun-dant nucleation sites and reduces the Li nucleation overpotential,thereby effectively suppressing Li den-drite growth.Moreover,the volume change and pulverization problems of Li metal anode during depo-sition/stripping also can be accommodated by the 3D skeleton.The optimization effect has been directly confirmed by in-situ optical and ex-situ scanning electron microscope observation.Therefore,highly sta-ble performance(158.4 mA h g^(-1) at 2 C after 200 cycles with a capacity retention of 95.24%)in Li@LCP-Cu||NCM811 coin cell can be achieved.Furthermore,the solid-state battery assembled with the hybrid anode,poly(vinylidene fluoride)(PVDF)-based polymer electrolyte and polyethylene oxide(PEO)interface functional layer also exhibits the best electrochemical and safety performance,which also proves that the Li@LCP-Cu anode has great potential for application in solid-state batteries.

关键词： Hot-pressing Hybrid anode Lithiophilic layer licx Li dendrite Solid-state batteries

Introduction of nanotwins into nanoprecipitations strengthened CoCrNiMo_(0.2) alloy to achieve strength and ductility trade-off:A comparative research

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Journal of Materials Science & Technology 2023年第25期156卷 172-182页

作者： Hao Zhang Ziyi Ren Yonggang Tong Yongle Hu Xixi Ji Lingwei Yang kaiming wang Jingzhong Fang Hui Chen Xiubing Liang College of Automotive and Mechanical Engineering Changsha University of Science and TechnologyChangsha 410114China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China School of Civil Engineering Changsha University of Science and TechnologyChangsha 410111China National Institute of Defense Technology Innovation Academy of Military Science PLA ChinaBeijing 100072China

Normal strengthening methods through precipitations and deformation obviously enhance the strength of metallic materials while resulting in the sacrifice of ductility,and synergistic improvement of strength and ductility is currently an urgent requirement.Herein we developed a cryogenic deformation combined with an annealing method to fabricate CoCrNiMo_(0.2) medium entropy alloy,which achieved an ultrahigh strength of 1.8 GPa with synergistic improvement in strength and ductility.Microstructure,mechanical performance,and strengthening mechanisms of the developed alloys were investigated compared with that prepared by the regular room temperature deformation method.It was found that high-density nanotwins were produced in CoCrNiMo_(0.2) MEA via cryogenic deformation.Fine grains,hard precipitations,and high volume fraction of nanotwins greatly strengthened the alloy,obtaining a yield and ultimate tensile strength of 1400 MPa and 1800 MPa.Ductility improvement of the developed alloy was mainly attributed to the production of deformation nanotwins due to the lower stacking fault energy,which greatly increases the dislocation storage ability,and thus,the ductility of the alloy was enhanced.

关键词： Nanotwins Mechanical properties Deformation behavior Strengthening mechanisms

Electrode structure enabling dendrite inhibition for high cycle stability quasi-solid-state lithium metal batteries

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Journal of Energy Chemistry 2023年第4期79卷 232-241页

作者： kaiming wang Ao Yu Zhiyi Zhou Fei Shen Manni Li Liang Zhang Weichang Guo Yifei Chen Le Shi Xiaogang Han State Key Laboratory of Electrical Insulation and Power Equipment School of Electrical EngineeringXi’an Jiaotong UniversityXi’an 710049ShaanxiChina School of Future Technology Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina National Innovation Platform(Center)for Industry-Education Integration of Energy Storage Technology Xi’an 710049ShaanxiChina

Lithium(Li)metal batteries(LMBs)are widely regarded as the ultimate choice for the next generation of high-energy–density batteries.However,the uncontrollable growth of Li dendrites formed by inhomogeneous deposition seriously hinders its commercialization.Although many studies have achieved significant results in inhibiting the formation of Li dendrites,it is still impossible to eradicate them completely.Therefore,regulating the deposition behavior,such as the growth direction of unevenly deposited Li,is preferable to unilaterally suppressing them in some cases.Here we report a structured anode that can confine the deposited Li within holes and tune it to become vertical-up/horizontal-centripetal mixed growth mode by optimizing the electric field/Li^(+)concentration gradient.The Li^(+) adsorbed by the poly(amic acid)(PAA)insulating layer coated on the anode surface can form the Li^(+)concentration gradient pointing to the center of the hole.Combined with the special electric field formed by the hole structure,it is favorable for the Li^(+)to move into the vertically arrayed holes and simultaneously deposit on the bottom and walls.Furthermore,both in-situ and ex-situ observations confirm that the growth mode is changed and the Li deposition morphology is denser,which can greatly delay capacity fading and prolong cycle life in both liquid and quasi-solid-state LMBs.All the results show that the novel anode provides a new perspective for deep research into solid-state LMBs.

关键词： Lithium metal batteries Structured anode Deposition behavior Quasi-solid-state

OFDM系统PAPR和OOB辐射联合抑制算法研究

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高技术通讯 2024年第2期34卷 143-150页

作者：王浩刘凯明北京邮电大学电子工程学院北京100876

正交频分复用(OFDM)技术具有频谱效率高和抗多径衰落能力强的优点,但存在高峰值平均功率比(PAPR)和高带外(OOB)辐射的固有缺点。部分PAPR抑制算法会导致OOB辐射升高,因此需要一种联合抑制OFDM系统的PAPR和OOB辐射的算法。本文提出了一... 详细信息

正交频分复用(OFDM)技术具有频谱效率高和抗多径衰落能力强的优点,但存在高峰值平均功率比(PAPR)和高带外(OOB)辐射的固有缺点。部分PAPR抑制算法会导致OOB辐射升高,因此需要一种联合抑制OFDM系统的PAPR和OOB辐射的算法。本文提出了一种新的结合线性压扩和简化限幅滤波的混合式PAPR和OOB辐射联合抑制算法,该算法采用连续分段线性压扩(CPLC)算法抑制信号PAPR,并对压扩后的信号进行频域滤波;然后采用简化限幅滤波(SCF)算法降低频域滤波导致的峰值再生,保证信号的OOB辐射不再升高。接收端采用迭代接收算法提高系统的误码率性能。仿真结果表明,与CPLC、SCF方案相比,所提算法可以达到更好的PAPR和OOB辐射联合抑制性能,同时通过迭代接收算法获得与原始信号相近的误码率(BER)性能。

关键词：正交频分复用(OFDM) 峰值平均功率比(PAPR) 带外(OOB)辐射线性压扩限幅滤波(CF)