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Effect of lamellarization on the microstructure and mechanical properties of marine 10Ni5CrMoV steel

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International Journal of Minerals,Metallurgy and Materials 2025年第02期 402-413页

作者： Tao Zou Yanwu dong Zhouhua Jiang Shuyang Du Yushuo Li School of Metallurgy Northeastern University Key Laboratory of Rolling and Automation Northeastern University Key Laboratory for Ecological Metallurgy of Multimetallic Ores (Ministry of Education) Northeastern University

Multistage heat treatment involving quenching(Q), lamellarizing(L), and tempering(T) is applied to marine 10Ni5CrMoV steel. The microstructure and mechanical properties were studied by multiscale characterizations, and the kinetics of reverse austenite transformation, strain hardening behavior, and toughening mechanism were further investigated. The lamellarized specimens possess low yield strength but high toughness, especially cryogenic toughness. Lamellarization leads to the development of film-like reversed austenite at the martensite block and lath boundaries, refining the martensite structure and lowering the equivalent grain size. Kinetic analysis of austenite reversion based on the JMAK model shows that the isothermal transformation is dominated by the growth of reversed austenite,and the maximum transformation of reversed austenite is reached at the peak temperature(750°C). The strain hardening behavior based on the modified Crussard–Jaoul analysis indicates that the reversed austenite obtained from lamellarization reduces the proportion of martensite, significantly hindering crack propagation via martensitic transformation during the deformation. As a consequence, the QLT specimens exhibit high machinability and low yield strength. Compared with the QT specimen, the ductile–brittle transition temperature of the QLT specimens decreases from-116 to-130°C due to the low equivalent grain size and reversed austenite, which increases the cleavage force required for crack propagation and absorbs the energy of external load, respectively. This work provides an idea to improve the cryogenic toughness of marine 10Ni5CrMoV steel and lays a theoretical foundation for its industrial application and comprehensive performance improvement.

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Quasi-periodic pulsations with double periods observed in Lyαemission during solar flares

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Science China(Technological Sciences) 2022年第1期65卷 139-146页

作者： LI dong Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210033China CAS Key Laboratory of Solar Activity National Astronomical ObservatoriesBeijing 100101China

Quasi-periodic pulsations(QPPs)are very common oscillation features during solar flares,which have been observed in almost the entire ***,the flare-related QPPs with double periods in the Lyα emission,particularly within a period ratio of about 2,were rarely *** this paper,we report the QPPs with double periods in the full-disk Lyαemission during the impulsive phase of four solar flares,i.e.,SOL2016-Feb-12,SOL2014-Oct-24,SOL2014-Jun-10,and *** fulldisk Lyαfluxes were recorded by the extreme-ultraviolet sensor on board the Geostationary Operational Environmental ***,the quasi-periods are estimated by the Markov chain Monte Carlo(MCMC)sampling ***,the double periods of around 3 and 1.5 min are detected in Lyαemissions,and their period ratio is roughly equal to *** 3-min QPP could also be detected in the local light curves measured by the Atmospheric Imaging Assembly at wavelengths of 304 and *** observations suggest that the double periodic QPPs could be regarded as the fundamental and harmonic modes of acoustic waves,which should be helpful to understand magnetohydrodynamic waves in the solar ***,we cannot rule out that the double periods are each caused by a different generation mechanism.

关键词： solar flares solar chromosphere oscillations UV radiation magnetohydrodynamics(MHD)

非对称型假体设计及全膝关节置换后的力学分析

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中国组织工程研究 2025年第3期29卷 510-516页

作者：苏德君董万鹏董跃福张吉超张震上海工程技术大学材料科学与工程学院上海市201620 徐州医科大学附属连云港医院江苏省连云港市222061

背景:全膝关节置换是治疗膝关节晚期病症的有效手段,但假体衬垫容易因内部应力变化而产生磨损失效,寿命有限且术后患者的活动能力降低。如何对假体进行改进设计来满足患者更多的需求是假体研究的重要方向。目的:基于半月板的形态设计一... 详细信息

背景:全膝关节置换是治疗膝关节晚期病症的有效手段,但假体衬垫容易因内部应力变化而产生磨损失效,寿命有限且术后患者的活动能力降低。如何对假体进行改进设计来满足患者更多的需求是假体研究的重要方向。目的:基于半月板的形态设计一种非对称型假体,并与对称设计的后稳定型假体进行比较,分析2种假体的应力分布情况和衬垫的接触面积变化,以探究非对称型假体设计是否存在优势。方法:通过有限元方法对1例膝骨关节炎患者进行模拟截骨和假体装配,建立基于非对称型假体及对称设计的后稳定型假体的全膝关节置换术后膝关节模型。在0°,10°,20°,30°的屈膝条件下,探究股骨假体、胫骨假体以及衬垫上的Mises应力,并通过对比衬垫内外侧的接触面积,分析全膝关节置换后膝关节生物力学变化和运动行为的改变。结果与结论:(1)在0°-30°的屈膝过程中,2种假体衬垫上的Mises应力峰值均表现出先减小后增大的趋势,且内侧始终大于外侧。(2)非对称型设计的假体与后稳定型假体相比,应力峰值更低;在屈膝30°时,非对称型假体衬垫内外侧的Mises应力峰值分别为15.81 MPa和11.95 MPa,后稳定型衬垫为16.70 MPa和13.76 MPa,两者内侧差值约为5.33%,而外侧则相差13.15%;对比股骨假体和胫骨假体上的Mises应力峰值,非对称型假体在屈膝过程中始终低于后稳定型假体。(3)在0°站立位时,后稳定型假体衬垫的内侧接触面积为17.96 mm^(2)、外侧为34.10 mm^(2);而非对称型假体衬垫的内外侧接触面积分别为105.47 mm^(2)和107.80 mm^(2),具有更大的接触面积且两侧差距更小。(4)结果表明,非对称型假体的生物力学表现更好,且能够对维持膝关节稳定性、提升关节活动度有所帮助。这种设计能够在一定程度上还原膝关节以内侧髁为轴进行外旋的运动机制,是一种更为有效的膝关节假体选择方案。

关键词：膝关节全膝关节置换非对称型假体设计生物力学有限元分析

Scattering of Tollmien-Schlichting waves by localized roughness in transonic boundary layers

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Applied Mathematics and Mechanics(English Edition) 2020年第7期41卷 1105-1124页

作者： Ming dong Department of Mechanics Tianjin UniversityTianjin 300072China Laboratory for High-Speed Aerodynamics Tianjin UniversityTianjin 300072China

The laminar-turbulent transition in boundary-layer flows is often affected by wall imperfections, because the latter may interact with either the freestream perturbations or the oncoming boundary-layer instability modes, leading to a modification of the accumulation of the normal modes. The present paper particularly focuses on the latter mechanism in a transonic boundary layer, namely, the effect of a two-dimensional(2 D) roughness element on the oncoming Tollmien-Schlichting(T-S) modes when they propagate through the region of the rapid mean-flow distortion induced by the roughness. The wave scattering is analyzed by adapting the local scattering theory developed for subsonic boundary layers(WU, X. S. and dong, M. A local scattering theory for the effects of isolated roughness on boundary-layer instability and transition: transmission coefficient as an eigenvalue. Journal of Fluid Mechanics, 794, 68–108(2006)) to the transonic regime, and a transmission coefficient is introduced to characterize the effect of the roughness. In the sub-transonic regime, in which the Mach number is close to, but less than, 1, the scattering system reduces to an eigenvalue problem with the transmission coefficient being the eigenvalue;while in the super-transonic regime, in which the Mach number is slightly greater than 1, the scattering system becomes a high-dimensional group of linear equations with the transmission coefficient being solved afterward. In the largeReynolds-number asymptotic theory, the K′arm′an-Guderley parameter is introduced to quantify the effect of the Mach number. A systematical parametric study is carried out,and the dependence of the transmission coefficient on the roughness shape, the frequency of the oncoming mode, and the K′arm′an-Guderley parameter is provided.

关键词： boundary layer scattering instability Tollmien-Schlichting(T-S)wave triple deck

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二维Janus LuClI的铁谷特性研究

原子与分子物理学报 2025年第2期42卷 159-168页

作者：朱靖欣郭三栋西安邮电大学电子工程学院西安710121

铁谷材料由于其固有的铁磁性质,可以产生自发谷极化,从而实现谷自由度的操纵.不同的谷极化状态为铁谷材料在信息传递领域的应用提供了可能性.在本文的工作中,采用了可靠的第一性原理计算方法,证明了Janus单层LuClI的动力学、力学和热力... 详细信息

铁谷材料由于其固有的铁磁性质,可以产生自发谷极化,从而实现谷自由度的操纵.不同的谷极化状态为铁谷材料在信息传递领域的应用提供了可能性.在本文的工作中,采用了可靠的第一性原理计算方法,证明了Janus单层LuClI的动力学、力学和热力学稳定性.发现Janus单层LuClI是一种有潜力的铁谷材料,它有着50.927 meV的谷劈裂.当Lu原子磁矩方向(平面外)发生颠倒时,可以实现谷极化翻转.还计算了Janus单层LuClI在布里渊区中的Berry曲率分布,主要集中在-K和K谷,可以实现反常谷霍尔效应.当电子关联强度比较小时,Janus单层LuClI的易磁化轴将指向面内,从而失去自发谷极化.尽管如此,利用应变调控可以使磁化方向从面内转向面外,从而产生谷极化.此外,Janus单层LuClI同时具有面内和面外压电响应,计算得到的面内压电应变系数d11大于大部分已有二维材料的计算值,而面外压电系数d31非常小.这为通过压电效应调控谷载流子提供了可能性.

关键词：铁谷材料压电第一性原理计算

Two new species of the genus Munidopsis Whiteaves,1874(Crustacea:Anomura:Munidopsidae)from the Caroline Ridge,South of the Mariana Trench

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Journal of Oceanology and Limnology 2021年第5期39卷 1841-1853页

作者： dong dong Xinzheng LI Department of Marine Organism Taxonomy&Phylogeny Institute of OceanologyChinese Academy of SciencesQingdao 266071China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao266071China University of Chinese Academy of Sciences Beijing 100049China Laboratory for Marine Biology and Biotechnology Pilot NationalLaboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

The genus Munidopsis has high biodiversity in seamount *** this study,two new Munidopsis species,Munidopsis ahyongi *** Munidopsis carolinensis *** the Caroline Ridge in the tropical western Pacific Ocean were *** *** very similar to a group of species in the *** complex,but can be readily distinguished from the related species in having the oblique posterior orbital margins,2 spines on the lateral carapace margin,and a relatively longer rostral median *** *** different from two related species primarily in having oblique frontal margins,blunt outer orbital angles,straight lateral margins of the rostrum,scale-like rugae on sternites 5-7,and less spinose pereopod 1(chelipeds,P1)merus and *** from the morphological comparisons,DNA barcode analysis and phylogenetic analysis based on the cytochrome c oxidase subunit I gene(COI)were employed for the identification of these new species.

关键词： Munidopsis new species seamount tropical western Pacific Ocean DNA barcodes

New insights into the synergistic degradation of organic pollutants by white rot fungi and minerals

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Science China Earth Sciences 2023年第9期66卷 2166-2168页

作者： Hailiang dong Center for Geomicrobiology and Biogeochemistry Research State Key Laboratory of Biogeology and Environmental GeologyChina University of GeosciencesBeijing 100083China

Soil pollution and other environmental issues have become a serious bottleneck affecting human health and sustainable socio-economic *** recent years,the problem of soil organic pollution has been increasingly prominent,garnering widespread attention from society and becoming a hot topic in the research *** urgent demand for ecological civilization and a habitable Earth environment by the nation has brought about new opportunities and challenges for in-depth research and development in soil pollution *** is imperative to conduct research related to important issues such as soil pollution prevention and control,Earth habitability,and other national requirements.

关键词： soil pollution Earth

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A Two-Dimensional Improvement for Farr-Gao Algorithm

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Journal of Systems Science & Complexity 2016年第5期29卷 1382-1399页

作者： dong Tian School of Mathematics Key Laboratory of Symbolic Computation and Knowledge Engineering (Ministry of Education) Jilin University

Farr-Gao algorithm is a state-of-the-art algorithm for reduced Gr?bner bases of vanishing ideals of finite points, which has been implemented in Maple as a build-in command. This paper presents a two-dimensional improvement for it that employs a preprocessing strategy for computing reduced Gr?bner bases associated with tower subsets of given point sets. Experimental results show that the preprocessed Farr-Gao algorithm is more efficient than the classical one.

关键词： Grobner basis GrSbner escalier Newton interpolation basis tower set vanishing ideal.

Detailed influences of ethanol as fuel additive on combustion chemistry of premixed fuel-rich ethylene flames

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Science China(Technological Sciences) 2015年第10期58卷 1696-1704页

作者： LIU dong School of Energy and Power Engineering Nanjing University of Science and Technology

To better understand potential pollutant formations during combustion of conventional hydrocarbon fuels blended with oxygenated fuels, detailed influences of ethanol as fuel additive on small polycyclic aromatic hydrocarbons(PAHs) precursors, aldehydes, ketene and other important intermediate species in premixed fuel-rich low-pressure ethylene flames are distinguished among dilution, thermal and chemical effects of additives. Dominant effects of ethanol addition on each species are underlined respectively. Ethylene oxidation process is delayed when ethylene is substituted by ethanol. The influence of ethanol dilution and thermal effects on ethylene consumption are larger than chemical effects. CO mole fractions slightly decrease mainly as a result of dilution and thermal effects of added ethanol. The reductions in small PAHs precursors(acetylene and propargyl) are attributed to dilution and thermal effects of ethanol addition instead of chemical effects. The ethanol chemical effects promote formations of hazardous pollutants formaldehyde and acetaldehyde, and especially are responsible for the significant increase of acetaldehyde. C2H6, C4H2 and C4H4 mole fractions decrease in a similar way with acetylene and propargyl as ethanol is added. Ethanol used here only serves as a prototype of oxygenated additive, and identification method in this work is more universal which can be easily extended for analyzing other fuel blends of hydrocarbon and oxygenated fuels.

关键词： ethylene flame ethanol addition chemical effect pollutant formations identification method