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China Ocean Engineering 2022年第4期36卷 601-613页

作者： CHENG Yong SONG fu-kai LI Ming-xin School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

The cross-flow(CF)vortex-induced vibration(VIV)of a deepwater steep wave riser(SWR)subjected to uniform or shear flow loads is investigated *** model is based on a three-dimensional(3D)nonlinear elastic rod theory coupled with a wake oscillator *** this numerical simulation,the nonlinear motion equations of the riser with large deformation features are established in a global coordinate system to avoid the transformation between global and local coordinate systems,and are discretized with the time-domain finite element method(FEM).A wakeoscillator model is employed to study the vortex shedding,and the lift force generated by the wake flow is described in a van der Pol equation.A Newmark-βiterative scheme is used to solve their coupling equation for the VIV response of the *** developed model is validated against the existing experimental results for the VIV response of the top-tension riser(TTR).Then,the numerical simulations are executed to determine VIV characteristics of the *** effects of both flow velocity and the spanwise length of the flow field on the drag coefficient in the inline(IL)direction and the lift coefficient in the CF direction are investigated *** results indicate that compared with TTR,the low frequency and multi-modal vibration are the main components of the SWR due to the large deformation and flexible *** shear flow,the multi-frequency resonance dominates the VIV response of the SWR,especially at the hang-off segment.

关键词： steep wave riser vortex-induced vibration time domain simulation nonlinear finite element wake oscillator

Ablation behaviour of C/C-HfC-SiC composites prepared by joint route of precursor infiltration and pyrolysis and gaseous silicon infiltration

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Chinese Journal of Aeronautics 2023年第9期36卷 426-436页

作者： Jiaping ZHANG Yuepeng xin Running WANG Qiangang fu Shaanxi Key Laboratory of Fiber Reinforced Light Composite materials Northwestern Polytechnical UniversityXi’an 710072China

C/C-SiC-HfC composites were fabricated by using Precursor Infiltration and Pyrolysis(PIP) combined with Gaseous Silicon Infiltration(GSI) process. Different GSI temperatures(1900 ℃ and 2100 ℃) were selected. The combination of PIP and GSI could significantly reduce the preparation time of the composites. The morphology displaying a rich-Si layer was formed on the surface of the composites prepared at GSI 2100 ℃. Ablation performance of the composites was investigated by oxyacetylene torch. The results showed that after ablation for 120 s, compared to the composites prepared by PIP + 1900 ℃ GSI, the linear and mass ablation rates of the composites fabricated by PIP + 2100 ℃ GSI were decreased from 8.05 μm/s to 5.06 μm/s and from 1.61 mg/s to 1.03 mg/s, respectively. The coverage of the rich-Si surface layer promoted the generation of more SiO_(2) during ablation, which not only benefited for decreasing the surface temperature but also contributed to the formation of H-Si-O glass and the HfO_(2) skeleton, thus better resisting the denudation of the oxyacetylene torch.

关键词： Ablation C/C composites GSI HfC-SiC PIP

Seismic behavior of precast segmental column bridges under near-fault forward-directivity ground motions

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Earthquake Engineering and Engineering Vibration 2022年第2期21卷 559-571页

作者： xin Lifeng Li Xiaozhen fu Peiyao Mu Di School of Mechanics Civil Engineering&ArchitectureNorthwestern Polytechnical UniversityXi′an 710072China Department of Bridge Engineering Southwest Jiaotong UniversityChengdu 610031China Department of Civil and Environmental Engineering Hanyang UniversitySeoul 04763Korea

Precast segmental column bridges exhibit various construction advantages in comparison to traditional monolithic column ***,the lack of cognitions on seismic behaviors has seriously restricted their applications and *** this paper,comprehensive investigations are conducted to analyze the dynamic characteristics of precast segmental column bridges under near-fault,forward-directivity ground ***,the finite-element models of two comparable bridges with precast segmental columns and monolithic columns are constructed by using OpenSees software,and the nonlinearities of the bridges are ***,three different earthquake loadings are meticulously set up to handle engineering problems,namely recorded near-and far-field ground motions,parameterized pulses,and pulse and residual components extracted from real ***,based on the models and earthquake sets,extensive explorations are carried *** results show that near-fault forward-directivity ground motions are more threatening than far-field ones;precast segmental column bridges may suffer more pounding impacts than monolithic bridges;the“narrow band”effect caused by near-fault,forward-directivity ground motions may occur in bridges with shorter periods than pulse periods;and pulse and residual components play different roles in seismic responses.

关键词： precast segmental column bridge monolithic column bridge seismic behavior near-fault forward-directivity ground motion pounding effect

In-situ Observation of Point Defect and Precipitate Evolvement of CLAM Steel under Electron Irradiation

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Journal of materials Science & Technology 2013年第5期29卷 467-470页

作者： Yong xin Tongda ma xin Ju Jie Qiu Department of Physics University of Science and Technology Beijing General Research Institute for Nonferrous Metals Institute of Nuclear and New Energy Technology Tsinghua University

The point defect and precipitate evolution of China low activation martensitic steel （CLAM） under electron beam irradiation were characterized by high voltage electron microscopy. The process was recorded in-situ on electronsensitive films. The irradiation dose rate was 1.78 × 10-3 dpa/s and the highest dose was 2.12 dpa/s. Irradiation introduced dislocation loops into the sub-grain, which increased density when the irradiation dose was increased from 0.53 dpa to 1.59 dpa at 723 K. The precipitate, found to be an M6C type, was irradiated at 773 K at the [011] plane direction. The precipitate morphology and structure were unchanged when the irradiation dose was increased to 2.12 dpa. Compared with the irradiation at 723 K in the sub-grain, no other defects were generated at the nearby grain boundary at 773 K.

关键词： martensitic steel Electron microscopy Electron irradiation Defect Precipitate

Tribological behavior of AISI302 austenitic stainless steel modified by elevated temperature nitrogen plasma immersion ion implantation

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中国有色金属学会会刊：英文版 2004年第z1期14卷 301-304页

作者： JIANG Shao-qun ma xin-xin SUN Yue School of materials Science and Engineering Harbin Institute of Technology Harbin 150001 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

AISI302 stainless steel samples were modified by elevated temperature nitrogen plasma immersion ion implantation at temperature ranging from 330 ℃ to 450 ℃. The tribological behaviors of the implanted layers of the samples were investigated. The samples were characterized by Auger electron spectroscopy (AES), glancing angle X-ray diffraction (GXRD), and nanoindentation. The results show that the implantation temperature plays an important rule on the microstructure and surface properties of the implanted layers. The thickness of the modified layer implanted at 390 ℃ is about 9 μm. It is improved about two orders compared with that of the implanted at room temperature. The surface nanohardness and the wear resistance of elevated temperature implanted layers increase significantly, and the friction coefficient decreases obviously in comparison with the unimplanted one. These data suggests that the improvement results from the formation of new phases such as ε-(Fe, Cr, Ni)2+xN, or noncrystal phase.

关键词： austenite stainless steel elevated temperature plasma immersion ion implantation tribology nanohardness

Study of Strange Quark mass in CFL Phase

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Communications in Theoretical Physics 2006年第5X期46卷 905-908页

作者： LI xin Lü Xiao-fu Department of Physics Sichuan University Chengdu 610064 China Institute of Theoretical Physics Academia Sinica P.O. Box 2735 Beijing 100080 China

In this paper we introduce bilocal fields in the global color symmetry model and consider color and electrical neutrality conditions simultaneously to study the effect of strange quark mass Ms for the momentum-dependent condensate of color-flavor locked phase. Consequently we find that there will be a quantum phase transition occurring.

关键词： global color model color superconductivity

Degradation of CTLA-4 balances toxicity and efficacy

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Science Bulletin 2019年第19期64卷 1388-1389页

作者： Zhenhua Ren Yang-xin fu The Department of Pathology UT Southwestern Medical CenterDallasTX75235-9072USA The Department of Immunology UT Southwestern Medical CenterDallasTX75235-9072USA

The notorious side effects of anti-CTLA-4 limit its use in the clinic,but what causes the severe side effects remains largely *** et al.[1]elucidated antibody-induced CTLA-4lysosomal degradation as a new mechanism accounting for the severe immunotherapy-related adverse effects and limited efficacy of anti-CTLA-4 ***-4 expresses on regulatory T cells(Tregs)and activated CD8 and CD4 effector cells.

关键词： Degradation CTLA-4 toxicity

Faceted interfaces: a key feature to quantitative understanding of transformation morphology

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npj Computational materials 2016年第1期2卷 44-57页

作者： Wen-Zheng Zhang xin-fu Gu fu-Zhi Dai School of materials Science and Engineering Tsinghua UniversityBeijingChina Institute for materials Research Tohoku UniversitySendaiJapan Science and Technology on Advanced functional Composite Laboratory Aerospace Research Institute of Materials and Processing TechnologyBeijingChina

Faceted interfaces are a typical key feature of the morphology of many microstructures generated from solid-state phase ***,prediction and simulation of this faceted morphology remain a challenge,especially for systems where irrational orientation relationships(ORs)between two phases and irrational interface orientations(IOs)are *** terms of structural singularities,this work suggests an integrated framework,which possibly encompasses all candidates of faceted *** structural singularities are identified from a matching pattern,a dislocation structure and/or a ledge *** resultant singular interfaces have discrete IOs,described with low-index g’s(rational orientations)and/orΔg’s(either rational or irrational orientations).Various existing models are grouped according to their determined results regarding the OR and IO,and the links between the models are clarified in the integrated *** of defect types as far as possible in a dominant singular interface often exerts a central restriction on the *** irrational IO is usually due to the elimination of dislocations in one direction,i.e.,an O-line *** methods using both three-dimensional and two-dimensional models for quantitative determinations of O-line interfaces are reviewed,and a detailed example showing the calculation for an irrational interface is *** association between structural singularities and local energy minima is verified by atomistic calculations of interfacial energies in fcc/bcc alloys where it is found that the calculated equilibrium cross-sections are in a good agreement with observations from selected alloys.

关键词： transformation rational interface

Tunable supramolecular hydrogels from polypeptidePEG-polypeptide triblock copolymers

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Science China Chemistry 2015年第6期58卷 1005-1012页

作者： Xiaohui fu Yong Shen Yinan ma Wenxin fu Zhibo Li Laboratory of Polymer Physics and Chemistry Institute of Chemistry Chinese Academy of Sciences School of Polymer Science and Engineering Qingdao University of Science and Technology

A series of ABA triblock copolymers of poly(?-(2-methoxy ethoxy)esteryl-glutamate)-block-poly(ethylene glycol)-blockpoly(?-(2-methoxy ethoxy)esteryl-glutamate) with poly(ethylene glycol) as middle hydrophilic B block and oligo(ethylene glycol)-functionalized polyglutamate(poly-L-EG2Glu) as terminal A blocks were prepared via ring-opening polymerization of EG2 Glu N-carboxyanhydride(NCA). The resulting P(EG2Glu)-b-PEG-b-P(EG2Glu) triblocks can spontaneously form hydrogels in water. The intermolecular hydrogen bonding interactions between polypeptides blocks were responsible for the formation of gel network structure. These hydrogels displayed shear-thinning and rapid recovery properties, which endowed them potential application as injectable drug delivery system. The mechanical strength of hydrogels can be modulated by copolymer composition, molecular weight and concentrations. Also, it was found that the hydrogels' strength decreased with temperature due to dehydration of polypeptide segments. Atomic force microscopy and scanning electron microscopy images revealed that these hydrogels were formed through micelle packing mechanism. Circular dichroism and Fourier transform infrared spectroscopy characterizations suggested the poly-L-EG2 Glu block adopted mixed conformation. A preliminary assessment of drug release in vitro demonstrated the hydrogels can offer a sustained release of doxorubicin(DOX) and the release rate could be controlled by varying chemical composition.

关键词： hydrogel polypeptide N-carboxyanhydride (NCA) ring-opening polymerization (ROP) drug delivery

Effect of Crystallization and Entropy Contribution Upon the Mechanical Response of Polymer Nano-fibers:A Steered Molecular Dynamics Study

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Chinese Journal of Polymer Science 2023年第3期41卷 465-474,I0011页

作者： Rui ma Dan Xu Chuan-fu Luo xinjiang Laboratory of Phase Transitions and Microstructures in Condensed matters College of Physical Science and TechnologyYili Normal UniversityYining 835000China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China School of Applied Chemistry and EngineeringHefei 230026China

The mechanical response of polyethylene nano-fibers with the same chain length but different chain numbers are studied by using steered molecular dynamics *** shrinking or stretching forces acted on the chain ends are investigated according to the chain-end distance and temperature under isothermal or continuous warming-cooling conditions,*** inflection point is found in the ForceDistance response when temperature is below 500 *** inflection point is related to the balance between entropy force and inter-monomer interaction and it reflects the strong effect of crystallization on the mechanical response of the *** force at inflection point is also affected by the buckling effect due to increased stiffness when crystallization *** two stages found in the Force-Temperature response and the difference between the shrinking and stretching forces indicate the hysteresis of crystallization and *** forces at different shrinking and stretching rates reveal the entropy contribution upon the mechanical response,indicated by the Ramachandran plot of *** chain-conformation entropy is majorly contributed by dihedrals and is quantified by the information entropy of dihedrals,which has a highly similarity to the mechanical Force-Temperature *** enlarged forces in multiple chains over a single chain are attributed to the enhanced dihedral-conformation *** study provides a new insight to the dynamically mechanical response of polymer nano-fibers according to the effect of crystallization and entropy contribution.

关键词： Polymer fibers Crystallization Entropy contribution Mechanical response