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Diffusion behavior at void tip and its contributions to void shrinkage during solid-state bonding

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Journal of Materials science & Technology 2018年第8期34卷 1449-1454页

作者： C.Zhang M.q.li H.li school of Materials science and Engineering Northwestern Polytechnical University state Key Laboratory of solidification Processing Northwestern Polytechnical University Department of Mechanical Engineering University de Lyon

solid-state diffusion bonding is an advanced joining technique, which has been widely used to join similar or dissimilar materials. Generally, it is easy to observe the diffusion behavior during dissimilar bonding, but for similar bonding the diffusion behavior has yet been observed via experiments. In this study, the diffusion behavior at void tip was firstly observed during similar bonding of stainless steel. scanning electron microscopy with energy dispersive spectroscopy was used to examine the interface charac- teristic and diffusion behavior. The results showed that a diffusion region was discovered at void tip. Element concentrations of diffusion region were more than those of void region, but less than those of bonded region. This behavior indicated that the diffusion was ongoing at void tip, but the perfect bond has yet formed. The diffusion region was attributed to the interface diffusion from adjacent region to void tip due to the stress gradient along bonding interface. The mass accumulation at void tip transformed the sharp void tip into smooth one at the beginning of void shrinkage, and then resulted in shorter voids.

关键词： stainless steel Micro-void morphology solid-state bonding Void tip Element diffusion

Xanthones from Garcinia pedunculata and Garcinia nujiangensis and their anti-inflammatory activity

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Chinese Journal of Natural Medicines 2025年第02期23卷 225-233页

作者： Xiaojie Fan Yufeng Jia Jiaxin Guo Jinyuan Yang Dahong li Huiming Hua Key Laboratory of structure-Based Drug Design & Discovery Ministry of Education and School of Traditional Chinese Materia Medica Shenyang Pharmaceutical University

Ten novel xanthones,garpedunxanthones A-G（1-5,6a/6b,7a/7b） and nujiangxanthone q（8）,along with sixteen known analogs（9-24）,were isolated from Garcinia pedunculata and *** structures were elucidated through high-resolution electrospray ionization mass spectrometry（HR-EsI-Ms） data,comprehensive nuclear magnetic resonance（NMR） spectroscopic analyses,and electronic circular dichroism（ECD） *** compounds without cytotoxicity were assessed for anti-inflammatory properties by measuring the inhibition of nitric oxide（NO） production in lipopolysaccharide（LPs）-induced ***-activity relationships are also *** 7b,19,and 21 exhibited significant anti-inflammatory activity with IC50values of 16.44±0.69,14.28±0.78,and 10.67±3.28 μmol·L-1,***-linked immunosorbent assay（ElisA） demonstrated that compounds 7b,19,and 21 inhibited the expression of pro-inflammatory cytokines TNF-α and IL-6 in a dose-dependent *** inhibitory effect of compo und 21 on IL-6 at 20 μmol·L-1was comparable to that of the positive *** network pharmacology studies,potential targets of compounds and inflammation were identified from PharmMapper and GeneCards *** Ontology（GO） and Kyoto Encyclopedia of Genes and Genomes（KEGG） enrichment analysis revealed that the overlapped targets were intricately associated with major pathogenic processes linked to inflammation,including positive regulation of mitogen-activated protein kinase（MAPK） cascade,protein kinase activity,NO synthase regulator activity,MAPK signaling pathway,and EGFR tyrosine kinase inhibitor resistance.

关键词： Anti-inflammation Garcinia nujiangensis Garcinia pedunculata Network pharmacology Xanthones

DYNAMIC MODEL AND sIMULATION OF EAF sTEELMAKING PROCEss

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Acta Metallurgica sinica(English Letters) 2003年第3期16卷 197-203页

作者： q.li X.Hong shanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 ChinaShanghai Enhanced Laboratory of Ferrometallurgy Shanghai University Shanghai 200072 China

Based on mass and energy balances and theories of thermodynamics and kinetics, a dynamic model in conjunction with relative operation parameters was derived. With this model, the EAF process in later stage of scarp melting was dynamically described, including time dependent variations of bath temperature, slag quantity, compositions of steel, slag and off-gas, etc. steelmaking process in a domestic 100 ton UHP AC EAF was chosen as a computational example, and the simulated variations of temperature of hot metal and element contents was shown consistent with the actual process measurements within average error scopes of |△T| si]|≤0.00027, |[△%Mn]|≤0.002, |[△%P]|≤0.00089 and |[△%s]|≤0.001 respectively at the test points. The model will be extended to predict the whole production process including scrap melting procedure and evaluate its energy and material consumption, the production efficiency, etc., which will provide assistance for the improvement of EAF operation and control.

关键词： EAF dynamic model simulation

strain Growth in Containment Vessels

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Transactions of Tianjin University 2006年第B9期12卷 193-198页

作者： DONG q li q M ZHENG J Y school of Mechanical Aerospace and Civil Engineering The University of Manchester PO Box 88 Manchester M60 1QD UK Institute of Chemical Machinery Zhejiang University Hangzhou 310027 China

strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using Ls-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

关键词： strain growth containment vessel dynamic response impulsive loading

Multi-soliton solutions of a two-component Camassa–Holm system:Darboux transformation approach

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Communications in Theoretical Physics 2020年第4期72卷 23-28页

作者： Gaihua Wang Nianhua li q P liu Department of Mathematics China University of Mining and TechnologyBeiing100083China school of Mathematical sciences Huaqiao UniversityQuanzhouFujian 362021China

We propose and develop another approach to constructing multi-soliton solutions of an integrable two-component Camassa–Holm(CH2)*** the help of a reciprocal transformation and a gauge transformation,we relate the CH2 system to a negative flow of the Broer–Kaup or twoboson *** solutions of this negative flow are given in terms of Wronskians via Darboux *** the multi-soliton solutions of the CH2 system are recovered in parametric form by inverting the reciprocal transformation and the gauge transformation.

关键词： Darboux transformation reciprocal transformation two-component Camassa–Holm system multi-soliton solutions

Effects of the Reversely Rotating Assisted shoulder on Microstructures During the Reverse Dual-rotation Friction stir Welding

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Journal of Materials science & Technology 2015年第4期31卷 375-383页

作者： J.q.li H.J.liu state Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Capital Aerospace Machinery Company

The reverse dual-rotation friction stir welding(RDR-FsW) has the capability to adjust the heat generation because of the separately designed tool shoulder and tool *** welding torque exerted on the workpiece by the reversely rotating shoulder is opposite to that exerted by the rotating tool pin,so the total welding torque is reduced,which is beneficial to reducing the clamping requirement of *** the present paper,a RDR-FsW joint was welded in a condition similar to the optimal welding condition of conventional FsW,and microstructures in various zones were investigated by comparison,aiming to highlight effects of the reversely rotating assisted *** to the heat conduction of the middle cylinder and the bottom end cover on which the assisted shoulder was machined,the thermal effect of RDR-FsW was smaller than that of the conventional ***,the effect of assisted shoulder on the plastic flow or deformation of material or was constrained in a thin layer near the weld top surface,and thus the flow of material especially along the thickness direction was clearly decreased in the *** the heat-affected zone(HAZ),the precipitate coarsening was the main evolution and was completed through the dissolution of small precipitates and the continuous growth of large *** contrast,the dissolution degree of precipitates increased significantly in the thermomechanically affected zone(TMAZ),and a small amount of original meta-stable precipitates transformed to block-shaped stable *** evolutions in the shoulder affected zone(sAZ)and the weld nugget zone were similar,*** majority of original meta-stable precipitates dissolved into the matrix and the remainder transformed to stable precipitates,though the dissolution degree was greater in the *** with the conventional FsW joint,the coarsening degrees of precipitates in the HAZ and TMAZ of RDR-FsW joint were much smaller,as well as the dissolution degrees of p

关键词： Friction stir welding Reverse dual-rotation fricti

Rapid drop in ductility of the bimodal-structured Mg-15Gd binary alloy during early aging

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Journal of Magnesium and Alloys 2024年第9期12卷 3772-3779页

作者： R.G.li s.q.Zhou H.Zhang R.Z.Wu D.Wu J.R.li B.s.liu s.s.li X.li B.J.Wang school of Mechanical and Power Engineering Shenyang University of Chemical TechnologyShenyang 110142China Key Laboratory of superlight Materials&surface Technology Ministry of EducationHarbin Engineering UniversityHarbin 150001China shenyang Key Laboratory for the Utilization Technology of Magnesium and Calcium Resources Shenyang University of Chemical TechnologyShenyang 110142China school of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang 110159China CAs Key Laboratory of Nuclear Materials and safety Assessment Institute of Metal ResearchChinese Academy of Sciences62 Wencui RoadShenyang 110016China

A bimodal-structured Mg^(-1)5Gd binary alloy with 45%volume fraction of elongated grains and 55%of dynamically recrystallized(DRXed)grains is fabricated by the extrusion *** precipitating behavior correlating with the evolution of mechanical properties is systematically characterized during the subsequent aging treatment at 200°*** extruded alloy presents an outstanding strength with tensile yield strength of 466 MPa and ultimate tensile strength of 500 MPa at peak aging condition,while the elongation drops from 9.2%in extrusion state to 3.1%.It is found there obviously exist a rapidly decreasing range of ductility at the early stage of *** during this time,the nano precipitates form preferentially at lamellar dislocation boundaries(LDBs)within the elongated grains,but there is no dense and uniform precipitation in the *** results suggest that the low elongation in the aged Mg^(-1)5Gd alloy is mainly attributed to the nano precipitates prior formed at the LDBs with a high density in the elongated *** related mechanism has been clarified.

关键词： Mg-Gd alloy Bimodal structure segregation Precipitate Dislocation Boundary

A subspace expanding technique for global zero finding of multi-degree-of-freedom nonlinear systems

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Applied Mathematics and Mechanics(English Edition) 2020年第5期41卷 769-784页

作者： Zigang li Jun JIANG lingHONG J.q.sUN Department of Mechanics School of ScienceXi’an University of Science and TechnologyXi’an 710054China state Key Laboratory for strength and Vibration Xi’an Jiaotong UniversityXi’an 710049China Department of Mechanical Engineering School of EngineeringUniversity of CaliforniaMercedCA 95343U.S.A.

A subspace expanding technique(sET) is proposed to efficiently discover and find all zeros of nonlinear functions in multi-degree-of-freedom(MDOF) engineering systems by discretizing the space into smaller subdomains, which are called cells. The covering set of the cells is identified by parallel calculations with the root bracketing method. The covering set can be found first in a low-dimensional subspace, and then gradually extended to higher dimensional spaces with the introduction of more equations and variables into the calculations. The results show that the proposed sET is highlyefficient for finding zeros in high-dimensional spaces. The subdivision technique of the cell mapping method is further used to refine the covering set, and the obtained numerical results of zeros are accurate. Three examples are further carried out to verify the applicability of the proposed method, and very good results are achieved. It is believed that the proposed method will significantly enhance the ability to study the stability, bifurcation,and optimization problems in complex MDOF nonlinear dynamic systems.

关键词： spatial discretization subspace expanding technique(sET) parallel computing subdivision global zero finding

specific Heat and Interface Energy of Nanostructured ZrAlNiCuCo Alloy

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Journal of Materials science & Technology 1997年第4期13卷 284-288页

作者： Jiang, q sui, ZX li, JC Xu, XY Dept. of Materials science and Engineering Jilin University of Technology Changchun 130025 China

The specific heat of the nanostructured crystals, the glass, the liquid and the crystals for a ZrAlNiCuCo alloy has been measured by using the differential scanning calorimeter. The specific heat value and its temperature coefficient of the nanostructured crystals are larger than that of the relaxed glass and of the crystals. Through measuring crystallization enthalpies and specific heat of the alloy in different states, the enthalpy differences among the crystals, the liquid and the nanostructured crystals are calculated and the interface energies of nanostructured crystals are estimated. The stability and the grain size limit of the nanostructured crystals are discussed.

关键词： Nanostructured materials