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The effects of ion screening on neutrino-nucleus interactions in core-collapse supernova explosions

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Research in Astronomy and Astrophysics 2010年第7期10卷 689-695页

作者： xiong-ping Xia Lin Yi Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

The effects of ion screening in stellar core collapses are investigated based on a new progenitor star model. Simulation results show that ion screening slightly affects the leptons and decreases explosion energy, which is a negative factor for energy transfer supernova explosions. We also investigate the effect on type Ⅱ-supernova explosions of neutrino-nucleus elastic scattering based on the new progenitor star model. It is shown that, compared with the previously calculated results, neutrinos-nucleus elastic scattering in stellar core collapses is more severe, leading to an obvious reduction of the neutrino leakage energy loss and an increase of supernova explosion energy.

关键词： stars supernovae general -- neutrino-nucleus

A Generalization of a Theorem of Liao

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Acta Mathematica Sinica,English Series 2006年第1期22卷 207-210页

作者： xiong ping DAI Zuo Ling ZHOU Depatment of Mathematics Nanjing University Nanjing 210093 P. R. China Lingnan College of Zhongshan University Guangzhou 510275 P. R. China

Let X be a metrizable space and let φ：R× X → X be a continuous flow on X. For any given {φt}-invariant Borel probability measure, this paper presents a {φt}-invariant Borel subset of X satisfying the requirements of the classical ergodic theorem for the contiImous flow （X, {φt}）. The set is more restrictive than the ones in the literature, but it might be more useful and convenient, particularly for non-uniformly hyperbolic systems and skew-product flows.

关键词： Ergodic theorem Liao theory

Efect of high temperature and high strain rate on the dynamic mechanical properties of Fe-30Mn-3Si-4Al TWIP steel

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International Journal of Minerals,Metallurgy and Materials 2013年第9期20卷 835-841页

作者： Zhi-ping xiong Xue-ping Ren Wei-ping Bao Jian Shu Shu-xia Li Hai-tao Qu School of Materials Science and Engineering University of Science and Technology Beijing School of Mechanical Materials and Mechatronic Engineering University of Wollongong School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The dynamic mechanical properties of Fe-30Mn-3Si-4A1 twinning induced plasticity （TWIP） steel were studied by the split-Hopkinson pressure bar （SHPB） at temperatures of 298-1073 K and strain rates of 700, 2500, and 5000 s-1. The TWIP steel indicates strain rate hardening effect between 700 and 2500 s-1, but it shows strain rate softening effect between 2500 and 5000 s-1. In addition, the strain rate softening effect enhances with an increase in deformation temperature. After deformation, the microstructures were studied by optical microscopy （OM）. It is shown that the deformation bands become more convergence, a part of which become interwoven with an increase in strain rate, and the dynamic recovery and recrystallization are enhanced with an increase in both temperature and strain rate.

关键词： TWIP steels mechanical properties strain rate temperature

Microstructure and antibacterial property of stainless steel implanted by Cu ions

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 328-331页

作者： XU Bo-fan NI Hong-wei xiong ping-yuan xiong Juan DAN Zhi-gang School of Material and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China School of Material and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China School of Medicine Science Wuhan 430081 China School of Material and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China School of Material and Metallurgy Wuhan University of Science and Technology Wuhan 430081 China

Copper ions were implanted into AISI 304 austenitic stainless steel by metal vapor vacuum are (MEVVA) with 60 - 100 keV energy and a dose range (0.2 - 5.0) × 1017 cm-2. Then Cu-implanted stainless steel was treated by a special antibacterial treatment. Antibacterial rates of Cu-implanted stainless steel, Cu-implanted stainless steel with special antibacterial treatment and un-implanted stainless steel were obtained by agar plate method. Phase composition in the implanted layer was analyzed by glancing X-ray diffraction (GXRD). Microstructure of antibacterial stainless steel was observed with transmission electron microscopy (TEM), and changes of the bacterium appearance after 24 h antibacterial action on the surface of un-implanted and Cu-implanted stainless steel with antibacterial treatment were observed with bio-TEM respectively. The results show that stainless steel obtains antibacterial property against E. coli when the Cu ions dose approaches to the saturated one. A suitable amount of Cu-rich phase uniformly disperses on the surface of Cu-implanted stainless steel that is treated by the special antibacterial treatment. The Cu-rich phase naked on the surface has a function of damage to pericellular membrane and cell wall,the pericellular membrane is thickened and the karyon degraded, and finally, bacteria die. Cu-rich phase naked on the surface endows stainless steel with best antibacterial property.

关键词： stainless steel copper ion implantation antibacterial property

Numerical analysis and optimization of the inlet stage of a multi-stage high pressure compressor

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航空动力学报 2007年第8期22卷 1356-1364页

作者： XU Quan-yong HOU An-ping xiong Jin-song ZHOU Sheng National Key Laboratory on Aero-engines School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100083

An opti mization process is used to redesign blades of a high-pressure *** artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick,stacking line andinlet angle using a 3Dapproach,with a significant efficiencyi mprovement at the design *** off-design behavior of this new compressor is also checked afterwards,which shows that the whole performance of the inlet stage is improved over a wide range of mass *** losses are reduced,proving the good performance of the opti *** whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.

关键词：数学分析最优化航天推进系统高压压缩机人工神经网络叶栅

Role of retained austenite in advanced high-strength steel:ductility and toughness

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Journal of Iron and Steel Research International 2024年第9期31卷 2079-2089页

作者： Vung Lam Nuam Hao Zhang Ying-chun Wang Zhi-ping xiong National Key Laboratory of Science and Technology on Materials under Shock and Impact School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing100081China Tangshan Key Laboratory of High-Performance Metals and Ceramics Tangshan Research Institute BITTangshan063000HebeiChina

Enhancing the ductility and toughness of advanced high-strength steels is essential for the wide range of promising *** retained austenite(RA)is a key phase due to the austenite-to-martensite transformation and its transformation-induced plasticity *** is commonly accepted that slow RA-to-martensite transformation is beneficial to ductility;therefore,the RA fraction and stability should be carefully *** RA stability is related to its morphology,size,carbon content,neighboring phase and ***,these factors are *** is noteworthy that the influence of RA on ductility and fracture toughness is not consistent because of their difference in stress *** is no clear relationship between fracture toughness and tensile ***,it is important to understand the role of RA in *** toughness is enhanced during the RA-to-martensite transformation,while the fracture toughness is decreased due to the formation of fresh and brittle *** a result,the findings regarding to the effect of RA on fracture toughness are *** investigations should be conducted in order to fully understand the effects of RA on ductility and fracture toughness,which can optimize the combination of ductility and toughness in AHSSs.

关键词： Retained austenite Ductility Toughness TRIP effect Steel

Effect of Temperature on Microstructure and Deformation Mechanism of Fe-30Mn-3Si-4Al TWIP Steel at Strain Rate of 700 s^(-1)

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Journal of Iron and Steel Research International 2015年第2期22卷 179-184页

作者： Zhi-ping xiong Xue-ping REN Jian SHU Zhe-lei WANG Wei-ping BAO Shu-xia LI School of Materials Science and Engineering University of Science and Technology Beijing School of Mechanical Materials and Mechatronic EngineeringUniversity of Wollongong China Nuclear Power Engineering Co. Ltd. School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

As twinning-induced plasticity （TWIP） steel is one potential material for shaped charge liner due to the combination of high strength and high plasticity, deformation mechanism at high strain rate and high temperature is required to study. Compression experiments of Fe 30Mn-3Si-4Al TWIP steel were conducted using a Gleeble 1500 thermal simulation machine and a split-Hopkinson pressure bar （SHPB） between 298 and 1073 K at strain rates of 10 3 and 700 s-1 , respectively. Microstructures were observed using optical microscopy （OM） and transmission e- lectron microscopy （TEM）. Results show that flow stress and densities of deformation twins and dislocations de crease with increasing deformation temperature at strain rates of 10 3 and 700 s -1. The stack fault energy （SFE） values （Г） of Fe-30Mn-3Si-4Al TWIP steel at different temperatures were calculated using thermodynamic data. Based on corresponding microstructures, it can he inferred that at 700 s -1 , twinning is the main deformation mecha- nism at 298-573 K for 30 mJ/m2≤Г≤63 mJ/m2 , while dislocation gliding is the main deformation mechanism above 1 073 K for Г≥145 mJ/m2. In addition, with increasing strain rate from 10-3 to 700 s -1 , the SFE range of twinning is enlarged and the SEF value of twinning becomes higher.

关键词： TWIP steel stack fault energy deformation mechanism SHPB

A non-precious metal catalyst for oxygen reduction prepared by heat-treating a mechanical mixture of carbon black,melamine and cobalt chloride

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Chinese Chemical Letters 2013年第12期24卷 1109-1111页

作者： Yu-Jun Si Zhong-ping xiong Chang-Guo Chen ping Liu Hui-Juan Wu College of Chemistry and Pharmaceutical Engineering Sichuan University of Science and Engineering College of Chemistry and Chemical Engineering Chongqing University

A non-precious metal catalyst CoMe]C for the oxygen reduction reaction is prepared by heat-treating a mechanical mixture of carbon black, melamine and cobalt chloride at 600 under nitrogen atmosphere for 2 h. The catalytic activity of CoMe/C is characterized by the electrochemical linear sweep voltammetry technique. The onset reduction potential of the catalyst is 0.55 V （vs. SCE） at a scanning rate of 5 mV/s in 0.5 mol/L H2SO4 solution. The formation of the ORR activity sites of CoMe/C is facilitated by metallic β- cobalt.

关键词： Oxygen reduction Non-precious metal catalyst Preparation Mechanical method

Microstructure Characteristics and Mechanical Properties of Nb-17Si-23Ti Ternary Alloys Fabricated by In Situ Reaction Laser Melting Deposition

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Acta Metallurgica Sinica(English Letters) 2018年第4期31卷 362-370页

作者： Wei Liu Hua-ping xiong Neng Li Shao-Qing Guo Ren-Yao Qin 3D Printing Research and Engineering Technology Center Beijing Institute of Aeronautical MaterialsBeijing 100095China

Fabrication of ternary Nb-17Si-23Ti alloys was attempted by in situ reaction laser melting deposition（LMD）with dual powder feeding method from Nb-28 at.% Ti powder mixture and pure Si *** microstructures of the as-deposited alloys were examined with scanning electronic microscope,and the phase constituents were analyzed by X-ray energy-dispersive spectrometer and X-ray ***,the effect of laser power on microstructure charac-teristics,microhardness and indentation fracture toughness was also *** in situ reaction LMD process resulted in remarkable refinement of the *** as-deposited samples mainly consisted of Nbss,metastable（NbTi）3Si and Ti-rich *** the increase in the laser power from 1000 to 2000 W,the Nbss morphology changed from discontinuous dendritic to near equiaxed,but the Ti-rich Nbss phase tended to ***,with the increase in the laser power,the microhardness of as-deposited samples increased from 822 to 951 HV,while the indentation fracture toughness was improved from 12.3 to 14.1 MPa mt/*** corresponding mechanism is also discussed.

关键词： Nb-Si-Ti alloys Laser melting deposition Microstructure Mechanical properties In situreaction