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Positron Annihilation Behaviors and Magnetic Properties of Single-phase Nd_2.e_(14)B and NanocompositeNd_2.e_(14)B/α-Fe Magnets

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Journal of materials Science & Technology 2001年第4期17卷 453-456页

作者： Dingkang XIONG, Xiaokai SUN,Liangyue XIONG, Wei LIU,Tong ZHAO and Zhidong ZHANG Institute of Metal Research, chinese academy of sciences, shenyang 110015,{2. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110015 China

Positron annihilation behaviors have been studied in the single phase Nd2.e14B magnet and the nanocomposite Nd2.e14B/α-Fe magnet, prepared by melt spinning. The results showed that the number of vacancy-cluster at grain boundaries increases with increasing annealing temperature for the both types of magnets. The increase of this kind of defect can improve the coercivity of the single-phase magnet. Conversely,the increase of vacancy-cluster amount leads to decreasing of the coercivity for the nanocomposite magnet. It implies that the mechanism of dominant magnetic hardening for the two types of magnets is different, and the domain walls pinning mechanism in the single-phase magnet and the reversal magnetization nucleation mechanism in the nanocomposite magnet operate, respectively.

关键词： Nd Positron Annihilation Behaviors and Magnetic Properties of Single-phase Nd2.e

2.5-dimensional angle potential field algorithm for the real-time autonomous navigation of outdoor mobile robots

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Science china(Information sciences) 2011年第10期54卷 2100-2112页

作者： QIU Quan 1,3 & HAN JianDa 2.1 Beijing Research center of Intelligent Equipment for Agriculture,Beijing 100097,china 2.State Key Laboratory of Robotics,{2. Institute of Automation,chinese academy of sciences,{2. 110016,china 3 National Research center for Intelligent Agricultural Equipment,Beijing 100097,china Beijing Research center of Intelligent Equipment for Agriculture Beijing China National Research center for Intelligent Agricultural Equipment Beijing China State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang China

A new real-time algorithm for the autonomous navigation of mobile robots equipped with laser scanners is proposed in this *** from the existing algorithms designed for 2.dimensional navigation problems,the new algorithm introduces the height information of the obstacles into the guidance process and behaves as a 2.5-dimensional angle potential field algorithm (2.5D-APF) to fulfill the navigation requirements under complex outdoor terrain ***,one laser scan is partitioned into two kinds of function sectors: guidance sector and inspecting ***,the guidance sector and the inspecting sectors are reconstructed to form a virtual guidance scan,where the 2.5D information is taken into ***,the conventional APF is improved to analyze the virtual guidance scan and generate the navigation *** new algorithm is tested on a tracked mobile robot,and the experimental results validate the proposed algorithm.

关键词： robot 2.5-dimensional outdoor real-time autonomous navigation

Phase Relationship in (Dy_(0.65)Tb_(0.2.)Pr_(0.1))Fe_x Alloys (1.6≤x≤2.1)

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Journal of materials Science & Technology 1996年第2期12卷 119-123页

作者： Bowen WANG Changheng WU Yuzhi CHUANG and Ximei JIN (Institute of Metal Research, chinese academy of sciences, shenyang 110015,{2.)(To whom correspondence should be addressed)(Present address: shenyang Institute of Technology shenyang, 110015,{2.) Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China shenyang Institute of Technology Shenyang 110015 China

The microstructure and phase relationship of (Dy0.65Tb0.2.Pr0.1)Fex alloys in the composition range of 1.6≤x≤2.1 were investigated using optical microscopy, X-ray diffraction , DTA and EPMA techniques. The variations of microstructure and lattice parameter with the iron content,the effect of heat treatment on the microstructure and the phase relationship have been *** phase relationship in the vicinity of the Laves phase is proposed

关键词： Fe_x Alloys Tb Pr Dy Phase Relationship in

Preparation of Nickel materials with Fractal Structure

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Journal of materials Science & Technology 2003年第3期19卷 229-231页

作者： Ruichun WANG, Jingdong GUO Benlian ZHOUshenyang National Laboratory for materials Science, Institute of Metal Research,{2., shenyang 110016, china Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

A way of manufacturing nickel material with fractal structure has been studied. Some algae with natural fractal structure were used as the basic substrates. The nickel was coated on the substrates by both electroless deposition and electrodeposition. After elimination of the foundational algae by erosion, dissolution etc, the pure nickel materials with fractal structure were obtained. At last, the specific surface area was analyzed by BET analyses and the fractal dimension of the nickel material was calculated by means of box-counting technique. The comparison of fractal dimension between Ni structure and natural algae was also given.

关键词： Fractal Nickel Algae Box counting

First-Principles Study of the Polar TiC/Ti Interface

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Journal of materials Science & Technology 2003年第6期19卷 540-544页

作者： Limin LIU, Shaoqing WANG and Hengqiang YEshenyang National Laboratory for materials Science, Institute of Metal Research,{2., shenyang 110016, china Lab. for Mat. Sci. Inst. of Metal Res. Chinese Acad. of Sci. Shenyang 110016 China

The interface structure, work of adhesion, and bonding character of the polar TiC/Ti interface have been examined by the first-principles density functional plane-wave pseudopotential calculations. Both Ti- and C-terminated interfaces including six different interface structures were calculated, which present quite different features. For the Ti-terminated interface, the interfacial Ti-Ti bond has a strong metallic and weak covalent character; while for the C-terminated interface, the interfacial bond is a strong polar covalent interaction between the Ti-3d and C-2. orbital. The work of adhesion of C-terminated interface is nearly 9 J/m2.stronger than that of the Ti-terminated. It is found that each termination has relatively large work of adhesion, which is consistent with other polar interfaces.

关键词： First-principles Metal/ceramic interface Adhesion Carbides

Cluster-based composition rule for Laves phase-related BCC solid solution hydrogen storage alloys

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Rare Metals 2006年第Z1期25卷 252-255页

作者： WANG Qing CHEN Feng WU Jiang QIANG Jianbing DONG Chuang ZHANG Yao XU Fen SUN Lixian State Key Laboratory of materials Modification Dalian University of Technology Dalian 116024 China State Key Laboratory of Materials Modification Dalian University of Technology Dalian 116024 China State Key Laboratory of Materials Modification Dalian University of Technology Dalian 116024 China State Key Laboratory of Materials Modification Dalian University of Technology Dalian 116024 China State Key Laboratory of Materials Modification Dalian University of Technology Dalian 116024 China International center of materials {2. Metals Research Institute Chinese Academy of Sciences Shenyang 110015 China Materials & Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Materials & Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China Materials & Thermochemistry Laboratory Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

A new cluster line approach for the composition rule of Laves phase-related BCC solid solution hydrogen-storage alloys was presented. The cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. In the Laves phase-related BCC solid solution alloy system such as Ti-Cr-V, Ti-Cr tends to form binary Cr2.i Laves phase while Ti-V and Cr-V to form solid solutions. This Laves phase is characterized by a close-packing icosahedral cluster Cr7Ti6. A cluster line Cr7Ti6-V is then constructed in this system. Alloy rods with a diameter of 3 mm of compositions along this line were prepared by copper-mould suction method. The alloy structure is found to vary with the V contents. Furthermore, the P-C-T measurements indicate that the cluster-line (Cr7Ti6)1-xVx alloys have large hydrogen storage capacities.

关键词： Ti-Cr-V alloys composition rule cluster hydrogen storage

Phase Transformation and Magnetostriction of (R-Pr)(Fe-T)_2.(R=Dy Tb; T=Co, Ni)

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Journal of materials Science & Technology 2000年第2期16卷 172-174页

作者： Zhijun GUO, Zhidong ZHANG, Xinguo ZHAO, Bowen WANG and Dianyu GENG (Institute of Metal Research, chinese academy of sciences, shenyang 110015,{2.) Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

Structure and magnetostriction of Dy1-Pr_x Fe_2.(0≤x≤0.5), Dy_0.6Pr_0.4(Fe_1-_yT_y)_2.(0≤y≤0.6), and Tb_1-z Pr_z(Fe_0.4Co_0.6)_2.(0≤z≤1.0) alloys (T=Co, Ni) have been investigated. It is found that the matrix of the alloys Dy_1-xPr_xFe_2.is a single phase (Dy, Pr)Fe_2.with MgCu_2.type structure and the second phase is (Dy, Pr)Fe_3 when x≤0.2. The amount of (Dy, Pr)Fe_3 phase increases with increasing Pr content and becomes the main phase when x=0.4. The matrix of Dy1_-***_xFe_2.is found to be the (Dy, Pr)_2.e_17 phase with Th_2.n_17-type structure when x=0.5. It is found that the amount of the cubic Laves phase (Dy, Pr)(Fe, Co)_2.in the Dy_0.6Pr_0.4(Fe_l-Co_y)2.increases with increasing Co concentration when 0≤y≤0.6. The substitution of Ni for Fe is nearly not favorable for the formation of the cubic Laves phase (Dy, Pr)(Fe, Ni)_2.in (Dy_1-xPr_x)Fe_2. The matrix of (Tb_1-z Pr_z)(Fe_0.4Co_0.6)_2.is a (Tb, Pr)(Fe, Co)_2.phase with the MgC_u2.type cubic Laves structure and a second phase of small amount is (Tb. Pr)(Fe, Co)_3 phase when z≤O.2. z=0.5 and 1.0. When 0.2.z≤0.4, the amount of the (Tb, Pr)(Fe, Co)_3 phase with PuNi_3-type structure increases with increasing z and becomes the main phase when z=0.4. When 0.52.exhibits a peak when x=0.3. The λ｜｜ - λ｜ for Dy_0.6Pr_0.4(Fe_1-y.M_y)_2.(M=Co, Ni) and Tb_l-zPrz(Fe_0.4Co_0.6)_2.is also examined.

关键词： Phase Transformation and Magnetostriction of R=Dy Tb R-Pr R Fe-T Dy Ni

INFLUENCE　OF　ENVIRONMENT　ON　TENSILE　BEHAVIOR　OF　Ni_3Al　SYNTHESIZED　UNDER　COMPRESSION

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Acta Metallurgica Sinica(English Letters) 1996年第1期9卷 12-16页

作者： LI Gang WANG Zhongguang LI Guangyi(State Key Laboratory of Fatigue and Fracture for materials,Institute of Metal Research,chinese {2. of sciences,shenyang 110015,china)V.OVCHARENKO(Institute of Strength physics and materials Science,Russian {2. of Inst of Metal Research Chinese Acad of Sciences Shenyang China

Self propagating high temperature synthesis(SHS) under compression was utilized to obtain an intermetallic compound Ni_3 Al by using elemental *** microstructure of the SHS product was observed by optical microscopy(OM) and scanning electron microscopy(SEM).The results reveal that the SHS Ni3Al is a single-phase polycrystalline alloy wilh LI2.crystal *** tests were conducted from room temperature to 800℃ both in air and in *** results show that the SHS Ni_3Al exhibits an anomalous temperature dependence of ultimate tensile *** ultimate tensile strength in vacuum is much higher than that in air over the whole temperature *** surfaces are characterized by the brittle grain boundary fracture and the intergranular fracture mode can not be affected markedly by the test environment.

关键词： Ni_3Al synthesis environment tensile behavior

Anomalous magnetotransport in LaMn_(1-x)Te_xO_3

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Science china(physics,Mechanics & Astronomy) 2009年第7期52卷 987-992页

作者： TAN GuoTai1,2. CHEN ZhengHao3 & ZHANG XiaoZhong4,5 1 Key Laboratory of Beam Technology & materials Modification of the Ministry of Education, Institute of Low Energy Nuclear physics, Beijing Normal University, Beijing 100875,{2. 2.Beijing Radiation center, Beijing 100875,{2. 3 Laboratory of Optical physics, Institute of physics, chinese academy of sciences, Beijing 100080,{2. 4 Key Laboratory of Advanced materials of the Ministry of Education, Department of materials Science and Engineering, Tsinghua University, Beijing 100084,{2. 5 Beijing National center for Electron Microscopy, Tsinghua University, Beijing 100084,{2. Key Laboratory of Beam Technology & materials Modification of the Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing China Beijing Radiation center Beijing China Laboratory of Optical physics Institute of Physics Chinese Academy of Sciences Beijing China Key Laboratory of Advanced materials of the Ministry of Education Department of Materials Science and Engineering Tsinghua University Beijing China Beijing National center for Electron Microscopy Tsinghua University Beijing China

The LaMn1-xTexO3+δ (x=0.1, 0.2. 0.3) were synthesized using solid-state reaction method for the first time. X-ray photoemission spectrum (XPS) shows that in the samples the Te ions have a valence of Te4+, and Mn3+ ions are partly converted into Mn2. and Mn4+ due to the excess oxygen and Te doping. The magnetotransport associated with Mn2., Mn3+ and Mn4+ was investigated. The experimental results show that the samples are insulator at 0 T when the amount of Mn3+ is much larger or less than the sum of Mn2. and Mn4+; by contrast, the samples display metal to insulator transition with increasing temperature when the amount of Mn3+ is close to the sum of Mn2. and Mn4+. These anomalous magnetotransport behaviors were analyzed in the frame of the double-exchange (DE) mechanism.

关键词： colossal magnetoresistance La-Te-Mn-O magnetotransport