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Hardness-thermal stability synergy in nanograined Ni and Ni alloys:Superposition of nanotwin and low-energy columnar boundary

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journal of Materials Science & Technology 2023年第6期137卷 123-131页

作者： F.H.Duan Y.Lin Q.Li j.H.Luan j.Lu j.pan Y.Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Department of Materials Science and Engineering City University of Hong KongHong KongChina Centre for Advanced Structural Materials Greater Bay Joint DivisionShenyang National Laboratory for Materials ScienceCity University of Hong Kong Shenzhen Research InstituteShenzhen 518057China City U-Shenzhen Futian Research Institute Shenzhen 518045China

Refining grains into nanoscale can significantly strengthen and harden metallic materials;however,nanograined metals generally exhibit low thermal stability,hindering their practical applications.In this work,we exploit the superposition of the contribution of nanotwins,low-angle grain boundaries,and microalloying to tailor superior combinations of high hardness and good thermal stability in Ni and Ni alloys.For the nanotwinned Ni having a twin thickness of∼2.9 nm and grain size of 28 nm,it exhibits a hardness over 8.0 GPa and an onset coarsening temperature of 623 K,both of which are well above those of nanograined Ni.Re/Mo microalloying can further improve the onset coarsening temperature to 773 K without comprising hardness.Our analyses reveal that high hardness is achieved via strengthen-ing offered by extremely fine nanotwins.Meanwhile,the superior thermal stability is mainly ascribed to the low driving force for grain growth induced by the low-angle columnar boundary architecture and to the additional pinning effect on the migration of twin/columnar boundaries provided by minor Re/Mo solutes.The present work not only reveals a family of nanotwinned metals possessing the combination of ultra-high hardness and high thermal stability but also provides a strategy for tailoring properties of metallic materials by pairing low-angle grain boundaries and twin boundaries.

关键词： Nanotwin Thermal stability Hardness Low-angle grain boundary Microalloying

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Unexpected creep behavior in a rejuvenated metallic glass

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journal of Materials Science & Technology 2023年第32期163卷 140-149页

作者： j.P.Wu Y.Lin F.H.Duan Q.Chen H.T.Wang N.Li j.L.Wen j.pan L.Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China State Key Laboratory of Material Processing and Die&Mould Technology and School of Materials Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Laboratory of Nanomaterials&Nanomechanics Department of Mechanical EngineeringCity University of Hong KongHong KongChina Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhan 430074China Shenzhen Polytechnic Shenzhen 518055China

Rejuvenation,bringing metallic glasses(MGs)to the younger and higher energy states,provides an alternative avenue to explore the interplay between the property and microstructures of MGs.In this study,the creep behavior of the Zr_(69.5)Cu_(12)Ni_(11)Al_(7.5)MGs was experimentally examined by controlling the energy state in terms of structural rejuvenation and thermal annealing.It is found that compared to the as-cast counterpart,the annealed MG at a lower energy state exhibits a higher hardness,a smaller displacement,and a lower creep rate due to the decreased free volume and the inhibited activation of the shear transformation zone.Conversely,the rejuvenated MG at a high energy state displays lower hardness and increased free volume content,yet it demonstrates superior creep resistance compared to its as-cast counterpart,which deviates from conventional understanding.This unexpected phenomenon occurs as the initial high-content free volume annihilates during creep,and strain hardening takes precedence over strain softening as the prevailing process during creep deformation,leading to a superior creep performance in extremely rejuvenated MGs.

关键词： Metallic glass Energy state Rejuvenation Creep Strain-hardening

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MICROSCOPIC CORROSION STUDIES OF DUPLEX STAINLESS STEELS

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Acta Metallurgica Sinica(English Letters) 2004年第5期17卷 625-631页

作者： C.Leygraf j.pan M.Femenia Division of Corrosion Science Department of Materials Science and EngineeringRoyal Institute of Technology(KTH)SE-100 44 StockholmSweden

Electrochemical scanning tunneling microscopy and scanning electrochemical microscopy have been used for in situ monitoring of localized corrosion processes of different Duplex stainless steels (DSS) in acidic chloride solutions. The techniques allow imaging of local dissolution events with micrometer resolution, as opposed to conventional electrochemical techniques, which only give an overall view of the corrosion behavior. In addition, combined scanning Kelvin probe force microscopy and magnetic force microscopy were used for mapping the Volta potential variation over the surface of DSSs. A significant difference in Volta potential between the austenite and ferrite phases suggests galvanic interaction between the phases. A compositional gradient appears within 2 micrometers across the phase boundary, as seen with scanning Auger microscopy (SAM). In all, the studies suggest that higher alloyed DSS exhibit a more homogeneous dissolution behavior than lower alloyed DSS, due to higher and more similar corrosion resistance of the two phases, and enhanced resistance of the ferrite/austenite phase boundary regions.

关键词： duplex stainless steel corrosion mechanism local electrochemical technique surface analysis micrometer resolution

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无监督机器学习可识别IPF的预测进展特征

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国际医学放射学杂志 2023年第2期 245-245页

作者： j.pan j.Hofmanninger K.H.Nenning F.Prayer S.R?hrich R.Sverzellati 张晨

摘要目的从特发性肺纤维化（IPF）队列的连续数据中识别和评估肺的预测性影像特征及其在IPF进展过程中的变化规律。测试这些影像指标能否预测结局。方法纳入76

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Recent Developments in Metallic Degradable Micromotors for Biomedical and Environmental Remediation Applications

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Nano-Micro Letters 2024年第3期16卷 1-35页

作者： Sourav Dutta Seungmin Noh Roger Sanchis Gual Xiangzhong Chen Salvador pané Bradley j.Nelson Hongsoo Choi Department of Robotics and Mechatronics Engineering Daegu Gyeongbuk Institute of Science and Technology(DGIST)Daegu 42988Republic of Korea DGIST‑ETH Microrobotics Research Center DGISTDaegu 42988Republic of Korea Multi‑Scale Robotics Lab Institute of Robotics and Intelligent SystemsETH Zurich8092 ZurichSwitzerland Institute of Optoelectronics State Key Laboratory of Photovoltaic Science and TechnologyShanghai Frontiers Science Research Base of Intelligent Optoelectronics and PerceptionFudan UniversityShanghai 200433People’s Republic of China

Synthetic micromotor has gained substantial attention in biomedicine and environmental remediation.Metal-based degradable micromotor composed of magnesium(Mg),zinc(Zn),and iron(Fe)have promise due to their nontoxic fuel-free propulsion,favorable biocompatibility,and safe excretion of degradation products Recent advances in degradable metallic micromotor have shown their fast movement in complex biological media,efficient cargo delivery and favorable biocompatibility.A noteworthy number of degradable metal-based micromotors employ bubble propulsion,utilizing water as fuel to generate hydrogen bubbles.This novel feature has projected degradable metallic micromotors for active in vivo drug delivery applications.In addition,understanding the degradation mechanism of these micromotors is also a key parameter for their design and performance.Its propulsion efficiency and life span govern the overall performance of a degradable metallic micromotor.Here we review the design and recent advancements of metallic degradable micromotors.Furthermore,we describe the controlled degradation,efficient in vivo drug delivery,and built-in acid neutralization capabilities of degradable micromotors with versatile biomedical applications.Moreover,we discuss micromotors’efficacy in detecting and destroying environmental pollutants.Finally,we address the limitations and future research directions of degradable metallic micromotors.

关键词： Magnesium Zinc Iron Biodegradable microrobot Biomedical Environmental

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2-local unstable homotopy groups of indecomposable A32-complexes

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Science China Mathematics 2024年第3期67卷 607-626页

作者： Zhongjian Zhu jianzhong pan College of Mathematics and Physics Wenzhou University Hua Loo-Keng Key Laboratory of Mathematics Institute of MathematicsAcademy of Mathematics and Systems ScienceChinese Academy of Sciences School of Mathematical Sciences University of Chinese Academy of Sciences

In this paper,we calculate the 2-local unstable homotopy groups of indecomposable A32-complexes.The main technique used is analysing the homotopy property of j(A,X),defined by Gray(1973) for a CW-pair(X,A),which is ho... 详细信息

关键词： homotopy groups A 2 n -complexes fibration sequence relative james construction 55P15

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冠状动脉阻塞性疾病:冠状动脉CT上反映阻塞远端反流的CT值反向递减征象是鉴别慢性完全闭塞和部分闭塞的一个有用的标志

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国际医学放射学杂志 2013年第3期 264-264页

作者： M.Li j.Zhang j.pan Z.Lu 丁静 Departments of Radiology and Cardiology Shanghai No.6 People’s HospitalSchool of MedicineShanghai Jiaotong University

目的通过CT冠状动脉成像来研究冠状动脉阻塞性疾病远端CT值反向递减(RAG)征象的临床价值。材料与方法本研究经过机构审查委员会批准,所有参与病人均签署书面知情同意书。在这项前瞻性研究中纳入连续的80例病人,年龄35～87岁,平均(67.1±... 详细信息

目的通过CT冠状动脉成像来研究冠状动脉阻塞性疾病远端CT值反向递减(RAG)征象的临床价值。材料与方法本研究经过机构审查委员会批准,所有参与病人均签署书面知情同意书。在这项前瞻性研究中纳入连续的80例病人,年龄35～87岁,平均(67.1±12.1)岁;其中男性62例,年龄35～86岁,平均(65.8±12.5)岁;女性18例,年龄58～87岁,平均(71.7±9.3)岁。RAG征象被定义为血管阻塞性病变远端管腔内反向的对比剂填充梯度,其表现为近端节段血管内CT值较低,而向远侧血管内CT值反而逐步增加。同时记录其他参数,如病变的长度和CT冠状动脉成像可见的桥血管。用Mann-Whitney秩和检验和Fisher精确检验进行统计学比较。结果共有94例阻塞性病变。介入性冠状动脉血管造影证实49例为慢性完全闭塞(CTO),45例部分闭塞(SO)。CTO组的RAG征象显著常见于SO组[65%(32/49)∶7%(3/45),P<0.001]。同样地,CT值梯度测量值[(5.1±13.4)HU/10mm∶(-13.4±68.7)HU/10mm,P<0.001]和病变长度[(23.6±22.7)mm∶(6±3)mm,P<0.001]两组间差异有统计学意义。在CT冠状动脉成像中仅有4例CTO观测到有侧支循环血管。在CT冠状动脉成像中所有具有RAG征象的血管,在介入性冠状动脉血管造影都显示有逆行的侧支循环血管供血。如结合所有这些参数来诊断CTO,敏感度和特异度分别为90%(44/49)和93%(42/45)。结论 RAG征象表明血管阻塞性病变远端存在逆行的侧支循环血流。这个征象对于诊断CTO具有高度特异性,并且有助于鉴别SO和CTO。

关键词：动脉阻塞性疾病 CTO 远端 CT 冠状动脉成像慢性完全闭塞征象

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Drug repurposing screen identifies vidofludimus calcium and pyrazofurin as novel chemical entities for the development of hepatitis E interventions

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Virologica Sinica 2024年第1期39卷 123-133页

作者： Hongbo Guo Dan Liu Kuan Liu Yao Hou Chunyang Li Qiudi Li Xiaohui Ding Monique M.A.Verstegen jikai Zhang Lingli Wang Yibo Ding Renxian Tang Xiucheng pan Kuiyang Zheng Luc j.Wvan der Laan Qiuwei pan Wenshi Wang Department of Pathogen Biology and Immunology Jiangsu Key Laboratory of Immunity and MetabolismJiangsu International Laboratory of Immunity and MetabolismXuzhou Medical UniversityXuzhou221004China Department of Gastroenterology and Hepatology Erasmus MC-University Medical CenterRotterdamNL-3015 CNthe Netherlands Department of Surgery Erasmus MC Transplant InstituteUniversity Medical CenterRotterdam3015CENL-3015 CNthe Netherlands Department of Infectious Diseases The Affiliated Hospital of Xuzhou Medical UniversityXuzhou221002China

Hepatitis E virus(HEV)infection can cause severe complications and high mortality,particularly in pregnant women,organ transplant recipients,individuals with pre-existing liver disease and immunosuppressed patients.However,there are still unmet needs for treating chronic HEV infections.Herein,we screened a best-in-class drug repurposing library consisting of 262 drugs/compounds.Upon screening,we identified vidofludimus calcium and pyrazofurin as novel anti-HEV entities.Vidofludimus calcium is the next-generation dihydroorotate dehydrogenase(DHODH)inhibitor in the phase 3 pipeline to treat autoimmune diseases or SARS-CoV-2 infection.Pyrazofurin selectively targets uridine monophosphate synthetase(UMPS).Their anti-HEV effects were further investigated in a range of cell culture models and human liver organoids models with wild type HEV strains and ribavirin treatment failure-associated HEV strains.Encouragingly,both drugs exhibited a sizeable therapeutic window against HEV.For instance,the IC50 value of vidofludimus calcium is 4.6–7.6-fold lower than the current therapeutic doses in patients.Mechanistically,their anti-HEV mode of action depends on the blockage of pyrimidine synthesis.Notably,two drugs robustly inhibited ribavirin treatment failure-associated HEV mutants(Y1320H,G1634R).Their combination with IFN-αresulted in synergistic antiviral activity.In conclusion,we identified vidofludimus calcium and pyrazofurin as potent candidates for the treatment of HEV infections.Based on their antiviral potency,and also the favorable safety profile identified in clinical studies,our study supports the initiation of clinical studies to repurpose these drugs for treating chronic hepatitis E.

关键词： Hepatitis Evirus(HEV) Drug repurposing Vidofludimus calcium Pyrazofurin Pyrimidine biosynthesis

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扩散张量成像结合常规MRI检查与少突胶质细胞瘤合并异酸脱氢酶1/2突变有关而与染色体lp/19q联合性缺失无关

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国际医学放射学杂志 2016年第4期 456-456页

作者： j.Xiong W.Tan j.Wen j.pan Y.Wang j.Zhang 宋玉坤 Department of Radiology Huashan Hospital of Fudan University

摘要目的探讨在少突胶质细胞瘤(OT)lp/19q联合性缺失以及异柠檬酸脱氢酶基因突变与常规MRI(cMRI)以及扩散张量成像(DTI)值之间的关系。材料与方法 84例少突胶质细胞瘤病人已经接受cMRI及DTI扫描,对其数据进行回顾性分析,通过测量各向异... 详细信息

摘要目的探讨在少突胶质细胞瘤(OT)lp/19q联合性缺失以及异柠檬酸脱氢酶基因突变与常规MRI(cMRI)以及扩散张量成像(DTI)值之间的关系。材料与方法 84例少突胶质细胞瘤病人已经接受cMRI及DTI扫描,对其数据进行回顾性分析,通过测量各向异性分数(FA)的最大值与表观扩

关键词：少突胶质细胞瘤异柠檬酸脱氢酶 DTI 扩散张量 MRI lp/19q 染色体联合性常规

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Crystal structure,phase transitions,and thermodynamic properties of magnesium metavanadate(MgV_(2)O_(6))

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journal of Magnesium and Alloys 2024年第4期12卷 1449-1460页

作者： Guishang Pei Cheng pan Dapeng Zhong junyi Xiang Xuewei Lv College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and Advanced Materials Chongqing UniversityChongqing 400044China pangang Group Research Institute Co. Ltd.Panzhihua 617000China

As a promising anode material for magnesium ion rechargeable batteries,magnesium metavanadate(MgV_(2)O_(6))has attracted considerable research interest in recent years.A MgV_(2)O_(6)sample was synthesized via a facile solid-state reaction by multistep-firing stoichiometric mixtures of MgO and V2O5 powder under an air atmosphere.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)occurred at 841 K and the enthalpy change was 4.37±0.04 kj/mol.The endothermic effect at 1014 K and the enthalpy change was 26.54±0.26 kj/mol,which is related to the incongruent melting ofβ-MgV_(2)O_(6).In situ XRD was performed to investigate phase transition of the as-prepared MgV_(2)O_(6)at high temperatures.The cell parameters obtained by Rietveld refinement indicated that it crystallizes in a monoclinic system with the C2/m space group,and the lattice parameters of a=9.280 A°,b=3.501 A°,c=6.731 A°,β=111.76°.The solid-state phase transition fromα-MgV_(2)O_(6)toβ-MgV_(2)O_(6)was further studied by thermal kinetics,indicating that this process is controlled first by a fibril-like mechanism and then by a spherulitic-type mechanism with an increasing heating rate.Additionally,the enthalpy change of MgV_(2)O_(6)at high temperatures was measured utilizing the drop calorimetry,heat capacity was calculated and given as:Cp=208.3+0.03583T-4809000T^(−2)(298-923 K)(j mol^(−1)K^(−1)),the high-temperature heat capacity can be used to calculate Gibbs free energy of MgV_(2)O_(6)at high temperatures.

关键词： MgV_(2)O_(6) Crystal structure Phase transitions Thermodynamic functions

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