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Acta Metallurgica Sinica(English Letters) 2017年第5期30卷 464-469页

作者： Kai Yang Jin-Shan Zhang xi-mei zong Wei Liu Chun-xiang Xu College of Materials Science and Engineering TaiyuanUniversity of Technology Taiyuan 030024 China Shanxi Key Laboratory of Advanced Magnesium-based Materials Taiyuan 030024China

The spheroidizing mechanism of W-phase in the Mg–Zn–Y–Mn–（B） alloys during solid-solution treatment was investigated by using kinetic methodologies. The microstructure and mechanical properties of heat-treated Mg_（94）Zn_（2.5）-Y_（2.5）Mn_1 alloy containing 0.003 wt% B were compared with heat-treated Mg_（94）Zn_（2.5）-Y_（2.5）Mn_1 alloy. The heat-treated Mg_（94）Zn_（2.5）-Y_（2.5）Mn_1 alloy with 0.003 wt% B contained fine and uniform W-phase particles, which exhibited optimal mechanical performance. The ultimate tensile strength, yield strength and elongation were 287.7, 125.5 MPa and 21.1%,respectively.

关键词： Magnesium alloys W-phase Spheroidizing Kinetics Microstructure Mechanical properties

Effect of Precipitated Phases on Corrosion of Mg95.8Gd3Zn1Zr0.2 Alloy with Long-Period Stacking Ordered Structure

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Acta Metallurgica Sinica(English Letters) 2016年第1期29卷 32-38页

作者： xi-mei zong Dan Wang Wei Liu Kai-Bo Nie Chun-xiang Xu Jin-Shan Zhang College of Materials Science and Engineering Taiyuan University of Technology Taiyuan 030024 China Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan 030024 China Department of Chemistry Taiyuan Normal UniversityTaiyuan 030031 China

The microstructure of the precipitated phases of ***3Zn1Zro.2 alloys with long-period stacking ordered structure before and after heat treatment is discussed. The corrosion properties of the as-cast （F）, solid-solution （T4） and aging-treated （T6） alloys in 1% NaC1 solution are studied. The hydrogen evolution and electrochemical measurements display that the as-cast ***3Zn1Zro.2 alloy with the continuous network eutectic phase exhibits the greatest corrosion resistance, while T6 sample with some needle-like phases and the particle phases is the worst among the three alloys. It is proposed to be mainly related to the amount, composition, microstructure and distribution of the precipitated phases.

关键词： Mg-Gd-Zn Corrosion properties Long-period stacking ordered (LPSO) Microstructure

8-ranks of Class Groups of Some Imaginary Quadratic Number Fields

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Acta Mathematica Sinica,English Series 2007年第11期23卷 2061-2068页

作者： xi mei WU Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016 P. R. China State Key Laboratory of Information Security Graduate School of Chinese Academy of Sciences Beijing 100039 P. R. China

Let F = Q（√-p1p2） be an imaginary quadratic field with distinct primes p1 = p2 = 1 mod 8 and the Legendre symbol （p1/p2） = 1. Then the 8-rank of the class group of F is equal to 2 if and only Pl if the following conditions hold：（1） The quartic residue symbols （p1/p2）4 = （p2/p1）4 = 1; （2） Either both p1 and p2 are represented by the form a^2 ＋ 32b^2 over Z and p^h2＋（2p1）/4=x^2-2p1y^2,x,y∈Z,or both p1 and p2 are not represented by the form a^2 ＋ 32b^2 over Z and p^h2＋（2p1）/4=ε（2x^2-p1y^2）,x,y∈Z,ε∈{±1},where h＋（2p1） is the narrow class number of Q（√2p1）,Moreover, we also generalize these results.

关键词： class group Rédei matrix reciprocity law

Effect of the Double Frequency of Trap Field in a Paul Trap

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Communications in Theoretical Physics 2001年第11期36卷 593-596页

作者： NIE zong-xiu FENG Mang LI Jiao-mei SHI Lei ZHU xi-Wen GAO Ke-Lin State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsThe Chinese Academy of SciencesWuhan 430071China

The effect of double frequency oftrap fieldφ=U-V1 cosΩt-V2 cos 2Ωt in a Paul trap can be described exactly by using a function series expansion to solve the corresponding Mathieu *** stability regions of a trapped ... 详细信息

关键词： double frequency trap field Paul trap

Theoretical Study of Haloacetonitrile Anions： CH2XCN^- （X=F, Cl）

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Chinese Journal of Chemical Physics 2008年第3期21卷 255-262页

作者： xin-wen Zhang mei Li Shan-xi Tian Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technologyof China Hefei 230025 China Department of Chemical Physics University of Science and Technology of China Hefei 230026China

Haloacetonitrile anions CH2XCN- （X=F, Cl） were studied by HF-SCF, Becke3-LYP, and MP2 methods together with the Dunning＇s basis set aug-cc-PVTZ. The vertical electron attachments to the neutral are endothermic. The geometrically optimized CH2FCN^- is mainly a valence-bounded anion and CH2FCN→CH2CN＋F^- is a nonadiabatic dissociation. This theoretical study in good agreement with the experimental results shows that the Becke3-LYP method is reasonable in describing the electronic structures of anions and dissociative attachment dynamics, while significant differences between MP2 and Becke3-LYP results are shown for the dissociation potential curves of CH2ClCN→CH2CN＋Cl^-.

关键词： Haloacetonitrile Electron attachment Dissociation dynamics Electron correlation effect

A Note on Calculation of Threshold Resonance by the Method of Complex Scaling

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Chinese Physics Letters 1996年第4期13卷 241-244页

作者： ZHAO mei-shan xiE xi-shun The Janies Franck Institute The University of ChicagoChicagoIllinois 60637USA Department of Physics University of MinnesotaMinneapolisMinnesota 55455USA Department of Physics Southeastern UniversityNanjing210096

A new approach to threshold resonance calculation by the complex scaling method is *** to scattering over a model potential barrier is presented and compared to a direct quantum scattering calculation.

关键词： calculation. scaling quantum

Two-Level Linear Clustering Protocol Based on Wireless Sensor Networks

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Journal of Electronic Science and Technology 2016年第3期14卷 257-261页

作者： mei Hu Yong-xi Wang the School of Electronic and Information Engineering Lanzhou Institute of TechnologyLanzhou 730050China

Aiming at the defects of the nodes in the low energy adaptive clustering hierarchy （LEACH） protocol, such as high energy consumption and uneven energy consumption, a two-level linear clustering protocol is built. The protocol improves the way of the nodes distribution at random. The terminal nodes which have not been a two-level cluster head in the cluster can compete with the principle of equivalent possibility, and on the basis of the rest energy of nodes the two-level cluster head is selected at last. The single hop within the cluster and single hop or multiple hops between clusters are used. Simulation experiment results show that the performance of the two-level linear clustering protocol applied to the Hexi corridor agricultural field is superior to that of the LEACH protocol in the survival time of network nodes, the ratio of success, and the remaining energy of network nodes.

关键词： Clustering energy-efficient farmland Hexi corridor low energy adaptive clustering hierarchy (LEACH) linear wireless sensor network (WSN).

Effects of the shape and size of rectangular inclusions on the fatigue cracking behavior of ultra-high strength steels

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International Journal of Minerals,Metallurgy and Materials 2013年第4期20卷 360-364页

作者： Yan-ping Zeng Hong-mei Fan xi-shan xie School of Materials Science and Engineering University of Science and Technology Beijing

The fatigue cracking behavior of ultra-high strength steels containing rectangular inclusions of small sizes were investigated based on in situ observations by scanning electron microscopy （SEM）. The size and shape of rectangular inclusions affect markedly the initiation site and propagation path of a fatigue crack. Especially, the initiation site of a fatigue crack depends strongly on the angle between the long-axis of a rectangle inclusion and the loading direction, and the length/width ratio of this rectangle inclusion because the residual stress distribution fields vary with these conditions. The results coincide very well with those of finite element analysis.

关键词： high strength steel inclusions fatigue of materials crack initiation crack propagation

Astrophysical constraints on the proton-to-electron mass ratio with FAST

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Research in Astronomy and Astrophysics 2019年第2期19卷 15-24页

作者： xi Chen Simon P.Ellingsen Ying mei Center for Astrophysics Guangzhou University Shanghai Astronomical Observatory Chinese Academy of Sciences School of Physical Sciences University of Tasmania

That the laws of physics are the same at all times and places throughout the Universe is one of the basic assumptions of physics. Astronomical observations provide the only means to test this basic assumption on cosmological time and distance scales. The possibility of variations in the dimensionless physical constant μ-the proton-to-electron mass ratio, can be tested by comparing astronomical measurements of the rest frequency of certain spectral lines at radio wavelengths with laboratory determinations. Different types of molecular transitions have different dependencies on μ and so observations of two or more spectral lines towards the same astronomical source can be used to test whether there is any evidence for either temporal or spatial changes in the physical fundamental constants. μ will change if the relative strength of the strong nuclear force compared to the electromagnetic force varies. Theoretical studies have shown that the rotational transitions of some molecules which have transitions in the frequency range that will be covered by FAST(e.g., CH_3 OH, OH and CH) are sensitive to changes in μ. A number of studies looking for possible variations in μ have been undertaken with existing telescopes, however, the greater sensitivity of FAST means it will open new opportunities to significantly improve upon measurements made to *** this paper, we discuss which molecular transitions and sources(both in the Galaxy and external galaxies)are likely targets for providing improved constraints on μ with FAST.

关键词： ISM:molecules radio lines:ISM techniques:radial velocities elementary particles

Synthesis and Crystal Structure of [Cp_2Ln(OC(SEt)NPh )]_2

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Chinese Journal of Structural Chemistry 2006年第2期25卷 131-134页

作者： ZHANG Chun-mei LIU Rui-Ting ZHOU xi-Geng Department of Chemistry Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Fudan University Shanghai 200433 China Department of Chemistry East China University of Science and Technology Shanghai 200237 China

Treatment of Cp3Y with EtSH, followed by reaction with an equivalent of PhNCO, yielded the dinuclear complex [Cp2Y（μ-η^1：η^3-OC（SEt）NPh）]2. The structure was characterized by elemental analysis, IR, MS and single-crystal X-ray diffraction analysis. The title compound crystallizes in triclinic, space group P1^- with a = 8.643（3）, b = 10.752（4）, c = 11.161（4）A°, α= 117.840（5）, β = 94.086（5）, γ= 101.008（5）°, V = 884.8（6） A°^3, Z = 1, Mr = 798.66 （C38H40N2O2S2Y2）, λ（MoKα） = 0.710730 .A°, ,μ= 3.417 mm^-1, Dc = 1.499 g/cm^3, F（000） = 408, the final R = 0.0453 and wR = 0.1007 for 3067 unique reflections （Rint = 0.0317） with 2357 observed ones （I 〉 2σ（I））. X-ray analysis reveals an unusual bonding mode of the OC（SEt）NPh ligand and the OCN fragment acts as a both bridging and side-on chelating ligand. Each yttrium atom is coordinated by two η^5-cyclopentadienyl groups, one chelating η^3-OC（SEt）NPh ligand and one bridging O atom from another η^3-OC（SEt）NPh ligand.

关键词： organolanthanide isocyanate insertion structure cyclopentadienyl