检索结果-南通市图书馆

An extraordinary-performance gradient nanostructured Hadfield manganese steel containing multi-phase nanocrystalline-amorphous core-shell surface layer by laser surface processing

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2023年第3期134卷 209-222页

作者： Wanting Sun jiasi Luo Yim Ying Chan j.H.luan Xu-Sheng Yang Research Institute for Advanced Manufacturing Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHung HomHong KongChina Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center The Hong Kong Polytechnic UniversityHung HomHong KongChina Department of Materials Science and Engineering City University of Hong KongHong KongChina

Reducing grain size(i.***.increasing the fraction of grain boundaries)could effectively strengthen nanograined metals but inevitably sacrifices the ductility and possibly causes a strengthening-softening transition below a critical grain size.In this work,a facile laser surface remelting-based technique was employed and optimized to fabricate a∼600μm-thick heterogeneous gradient nanostructured layer on an austenitic Hadfield manganese steel,in which the average grain size is gradually decreased from∼200μm in the matrix to only∼8 nm in the nanocrystalline-amorphous core-shell topmost surface.Atomic-scale microstructural characterizations dissected the gradient refinement processes along the gradient direction,i.***.transiting from the dislocations activities and twinning in sub-region to three kinds of martensitic transformations,and finally a multi-phase nanocrystalline-amorphous core-shell structural surface.Mechanical tests(e.***.nanoindentation,bulk-specimen tensile,and micro-pillar compression)were conducted along the gradient direction.It confirms a tensile strength of∼1055 MPa and ductility of∼10.5%in the laser-processed specimen.Particularly,the core-shell structural surface maintains ultra-strong(tensile strength of∼1.6 GPa,micro-pillar compressive strength of∼4 GPa at a strain of∼8%,and nanoindentation hardness of∼7.7 GPa)to overcome the potential strengthening-softening transition.Such significant strengthening effects are ascribed to the strength-ductility synergetic effects-induced extra work hardening ability in gradient nanostructure and the well-maintained dislocation activities inside extremely refined nanograins in the multi-phase nanocrystalline-amorphous core-shell structural surface,which are evidenced by atomic-scale observations and theoretical analysis.This study provides a unique hetero-nanostructure through a facile laser-related technique for extraordinary mechanical performance.

关键词： Laser surface processing Hadfield manganese steel Gradient nanostructure Nanocrystalline-amorphous Martensitic transformation

High-quality 8-fold self-compression of ultrashort near-UV pulses in an Ar-filled ultrathin-walled photonic crystal fiber

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Photonics Research 2022年第10期10卷 2405-2409页

作者： jIE luan PHILIP ST.j.RUSSELL DAVID NOVOA Max Planck Institute for the Science of Light 91058 ErlangenGermany Department of Physics Friedrich-Alexander-Universität91058 ErlangenGermany Department of Communications Engineering Engineering School of BilbaoUniversity of the Basque Country(UPV/EHU)48013 BilbaoSpain EHU Quantum Center University of the Basque Country(UPV/EHU)48013 BilbaoSpain IKERBASQUE Basque Foundation for Science48009 BilbaoSpain Previously with the Max Planck Institute for the Science of Light 91058 ErlangenGermany

We demonstrate generation of 7.6 fs near-UV pulses centered at 400 nm via 8-fold soliton-effect self-compression in an Ar-filled hollow-core kagomé-style photonic crystal fiber with ultrathin core walls.Analytical calculations of the effective compression length and soliton order permit adjustment of the experimental parameters,and numerical modeling of the nonlinear pulse dynamics in the fiber accurately predicts the spectrotemporal profiles of the self-compressed pulses.After compensation of phase distortion introduced by the optical elements along the beam path from the fiber to the diagnostics,71%of the pulse energy was in the main temporal lobe,with peak powers in excess of 0.2 GW.The convenient setup opens up new opportunities for time-resolved studies in spectroscopy,chemistry,and materials science.

关键词： fiber ultrashort filled

Anti-aging effect riboflavin via endogenous antioxidant in fruit fly drosophila melanogaster

在线全文

学校读者我要写书评

暂无评论

Anti-aging effect riboflavin via endogenous antioxidant in f...

首届东方药理论坛暨2018年全国心脑血管药理学术会议、上海市药理学会第十九届学术年会

作者： Y.-X ZOU M.-H RUAN j.luan X.FENG S.CHEN Zhi-Yong Chu Naval Medical Research Institute jiangxi University of Traditional Chinese Medicine

Objectives:This study investigated the effect of riboflavin on aging in Drosophila melanogaster（fruit fly）.Design:Experimental study.Setting:Naval Medical Research Institute.Participants:Fruit fly Drosophila melanogaster.Intervention:After lifelong supplement of riboflavin,the lifespan and the reproduction of fruit flies were observed.Hydrogen peroxide（H2 O2） was used to mimic oxidative stress damage to fruit flies and the survival time was recorded.Measurements:The activity of copper-zinc-containing superoxide dismutase（SOD1）,manganese containing SOD（SOD2） and catalase（CAT） and lipofuscin（LF） content were determined.Results:Riboflavin significantly prolonged the lifespan（Log rankχ2=16.677,P<0.001） and increased the reproductive capacity（P<0.01 for day 15;P<0.05 for day 30） of fruit flies by lifelong supplement.The survival time of fruit flies damaged by H2 O2 was significantly prolonged（Log rank χ2=15.886, P<0.001）,the activity of SOD1（P<0.01） and CAT（P<0.01） was enhanced,and the accumulation of LF（P<0.01） was inhibited by riboflavin supplement.Conclusion:Riboflavin prolonged the lifespan and increased the reproduction of fruit flies through anti-oxidative stress pathway involving enhancing the activity of SOD 1 and CAT and inhibiting LF accumulation.Riboflavin deserves more attention for slowing human aging.

关键词： riboflavin aging lifespan reproduction oxidativestress

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

聚乳酸柔性定形相变薄膜的制备及性能研究

工程热物理学报 2024年第5期45卷 1458-1463页

作者：吴学红栾林林赵敏陈亚南吕财刘勇常志娟李文浩郑州轻工业大学郑州450000

为解决相变材料易泄漏和力学性能差的问题,以聚乳酸(PLA)为基底,聚乙二醇(PEG)为相变工质,制备PEG/PLA相变薄膜。对其热性能和力学性能进行测试,结果表明,PLA作为支撑基底有效防止了PEG液体的泄漏。PEG/PLA配比为180/100时,相对焓效率最... 详细信息

为解决相变材料易泄漏和力学性能差的问题,以聚乳酸(PLA)为基底,聚乙二醇(PEG)为相变工质,制备PEG/PLA相变薄膜。对其热性能和力学性能进行测试,结果表明,PLA作为支撑基底有效防止了PEG液体的泄漏。PEG/PLA配比为180/100时,相对焓效率最高,达到103.87%,其熔融和凝固过程中的潜热分别为128.5j·g^(-1)和120.2j·g^(-1)。随着PEG比例的增加,薄膜的杨氏模量逐渐减小,PEG/PLA配比为180/100时,杨氏模量为152.2MPa,比纯PLA降低了73.2%,薄膜的柔韧性得到提升。

关键词：柔性相变薄膜聚乳酸热性能力学性能

LNP-CpG ODN-adjuvanted varicella-zoster virus glycoprotein E induced comparable levels of immunity with Shingrix^(TM) in VZV-primed mice

在线全文

学校读者我要写书评

暂无评论

Virologica Sinica 2022年第5期37卷 731-739页

作者： Ning luan Han Cao Yunfei Wang Kangyang Lin Cunbao Liu Institute of Medical Biology Chinese Academy of Medical Sciences and Peking Union Medical CollegeKunming 650118China

Latent varicella-zoster virus(VZV)may be reactivated to cause herpes zoster,which affects one in three people during their lifetime.The currently available subunit vaccine Shingrix^(TM) is superior to the attenuated vaccine Zostavax®in terms of both safety and efficacy,but the supply of its key adjuvant component QS21 is limited.With ionizable lipid nanoparticles(LNPs)that were recently approved by the FDA for COVID-19 mRNA vaccines as carriers,and oligodeoxynucleotides containing CpG motifs(CpG ODNs)approved by the FDA for a subunit hepatitis B vaccine as immunostimulators,we developed a LNP vaccine encapsulating VZV-glycoprotein E(gE)and CpG ODN,and compared its immunogenicity with Shingrix^(TM) in C57BL/6j mice.The results showed that the LNP vaccine induced comparable levels of gE-specific IgG antibodies to Shingrix^(TM) as determined by enzymelinked immunosorbent assay(ELISA).Most importantly,the LNP vaccine induced comparable levels of cellmediated immunity(CMI)that plays decisive roles in the efficacy of zoster vaccines to Shingrix^(TM) in a VZVprimed mouse model that was adopted for preclinical studies of Shingrix^(TM) .Number of IL-2 and IFN-γsecreting splenocytes and proportion of T helper 1(Th1)cytokine-expressing CD4^(+)T cells in LNP-CpG-adjuvanted VZV-gE vaccinated mice were similar to that of Shingrix^(TM) boosted mice.All of the components in this LNP vaccine can be artificially and economically synthesized in large quantities,indicating the potential of LNP-CpGadjuvanted VZV-gE as a more cost-effective zoster vaccine.

关键词： Varicella zoster virus(VZV) Subunit vaccine Adjuvant Lipid nanoparticle(LNP) CpG oligodeoxynucleotide(CpG ODN) AS01B Humoral immunity Cell-mediated immunity(CMI)

基于谷胱甘肽/谷胱甘肽过氧化物酶4轴探讨雷公藤甲素引起肝细胞铁死亡的作用机制

在线全文

学校读者我要写书评

暂无评论

中草药 2024年第9期55卷 2967-2975页

作者：王伟艳刘珊李会芳常银霞栾智华苏越蕊魏砚明山西中医药大学中药与食品工程学院山西晋中030619 山西中医药大学实验管理中心山西晋中030619

目的观察雷公藤甲素对铁代谢和脂质过氧化的影响,探讨雷公藤甲素引起肝细胞铁死亡的可能机制。方法利用雷公藤甲素处理人正常肝细胞HL7702和C57BL/6j小鼠,或利用铁死亡抑制剂(ferrostatin-1,Fer-1)和雷公藤甲素共同处理HL7702细胞,CCK-... 详细信息

目的观察雷公藤甲素对铁代谢和脂质过氧化的影响,探讨雷公藤甲素引起肝细胞铁死亡的可能机制。方法利用雷公藤甲素处理人正常肝细胞HL7702和C57BL/6j小鼠,或利用铁死亡抑制剂(ferrostatin-1,Fer-1)和雷公藤甲素共同处理HL7702细胞,CCK-8法检测细胞存活率;普鲁士蓝染色观察铁沉积;试剂盒检测铁离子、谷胱甘肽(glutathione,GSH)、丙二醛(malondialdehyde,MDA)含量以及超氧化物歧化酶(superoxide dismutase,SOD)、丙氨酸氨基转移酶(alanine aminotransferase,ALT)、天冬氨酸氨基转移酶(aspartate aminotransferase,AST)活性;qRT-PCR或Western blotting检测转铁蛋白受体1(transferrin receptor 1,TFR1)、谷胱甘肽过氧化物酶4(glutathione peroxidase 4,GPX4)、前列腺素内过氧化物合成酶2(prostaglandin-endoperoxide synthase 2,PTGS2)、长链脂酰辅酶A合成酶4(acyl-CoA synthetase long-chain family member 4,ACSL4)的表达。结果雷公藤甲素显著降低细胞存活率(P<0.05),引起铁沉积,升高血清中ALT、AST活性(P<0.05),增加HL7702细胞和小鼠肝组织中铁离子、MDA含量(P<0.05),降低GSH含量、SOD活性和GPX4表达(P<0.05),上调TFR1、PTGS2及ACSL4表达(P<0.05)。Fer-1显著上调细胞存活率和GPX4表达量(P<0.05),显著下调铁离子含量、TFR1、PTGS2及ACSL4表达(P<0.05)。结论雷公藤甲素可能通过GSH/GPX4轴引起铁代谢异常和脂质过氧化,诱导肝细胞铁死亡。

关键词：雷公藤甲素铁死亡肝细胞毒性铁超载脂质过氧化谷胱甘肽/谷胱甘肽过氧化物酶4轴

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

在线全文

学校读者我要写书评

暂无评论

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

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

面向危险化学品事故的事理图谱构建

中国安全科学学报 2024年第5期34卷 195-203页

作者：李红儒栾婷婷邓明月陈文涛张雪北京石油化工学院安全工程学院北京102617 应急管理部信息研究院北京100029

为提高危险化学品企业安全管理水平,构建危险化学品事故因果关系事理图谱。首先,依据事故调查报告,提出一种基于改进CasRel的实体关系联合抽取模型,该模型通过关系感知双向编码器表征法(R-Bert)和Span指针网络提高文本信息的抽取准确性... 详细信息

为提高危险化学品企业安全管理水平,构建危险化学品事故因果关系事理图谱。首先,依据事故调查报告,提出一种基于改进CasRel的实体关系联合抽取模型,该模型通过关系感知双向编码器表征法(R-Bert)和Span指针网络提高文本信息的抽取准确性;其次,利用相似度计算方法进行事件泛化,使得图谱更加完整和准确,并将其存储在图数据库Neo4j中,以可视化的方式直观展示事件之间的关联;最后,基于构建的事理图谱,设计出与之匹配的问答系统架构,开发危险化学品事故因果关系智能问答系统。研究结果表明:改进的CasRel模型计算结果F_(1)值为90.5%,较未改进模型准确率提升约2%。构建的危险化学品事故事理图谱及智能问答系统,在多个评价指标表现良好,能够清晰揭示事件之间的逻辑关系;所提方法可满足危险化学品事故知识问答需求,协助探究事故发生的规律和潜在风险因素,推断事故发展趋势。

关键词：危险化学品事故事理图谱知识抽取因果关系智能问答系统

Cu-assisted austenite reversion and enhanced TRIP effect in maraging stainless steels

在线全文

学校读者我要写书评

暂无评论

journal of Materials Science & Technology 2022年第9期104卷 52-58页

作者： M.C.Niu K.Yang j.H.luan W.Wang Z.B.jiao School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Shi-changxu Innovation Center for Advance Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina Department of Materials Science and Engineering City University of Hong KongHong KongChina The Hong Kong Polytechnic University Shenzhen Research Institute ShenzhenGuangdongChina

Control of the formation and stability of reverted austenite is critical in achieving a favorable combination of strength,ductility,and toughness in high-strength steels.In this work,the effects of Cu precipitation on the austenite reversion and mechanical properties of maraging stainless steels were investigated by atom probe tomography,transmission electron microscopy,and mechanical tests.Our results indicate that Cu accelerates the austenite reversion kinetics in two manners:first,Cu,as an austenite stabilizer,increases the equilibrium austenite fraction and hence enhances the chemical driving force for the austenite formation,and second,Cu-rich nanoprecipitates promote the austenite reversion by serving as heterogeneous nucleation sites and providing Ni-enriched chemical conditions through interfacial segregation.In addition,the Cu precipitation hardening compensates the strength drop induced by the formation of soft reverted austenite.During tensile deformation,the metastable reverted austenite transforms to martensite,which substantially improves the ductility and toughness through a transformation-induced plasticity(TRIP)effect.The Cu-added maraging stainless steel exhibits a superior combination of a yield strength of~1.3 GPa,an elongation of~15%,and an impact toughness of~58 j.

关键词： Maraging stainless steel TRIP effect Austenite reversion Cu-rich nanoprecipitate