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Effects of carbon on Pr_(0.15)Tb_(0.30)Dy_(0.55)Fe_(1.85) compound

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Rare Metals 2006年第z2期25卷 220-222页

作者： liU Heyan li yangxian YU Xiao li Songtao MENG Xiangxi XU Xuewen School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China Department of Physics North China Electric Power University Baoding 071003 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China

The structure, Curie temperature and magnetostriction of Pr0.15Tb0.30Dy0.55Fe1.85Cx (x=0-0.1) compounds were investigated by X-ray diffraction, a vibrating sample magnetometer and a standard strain technique. All the samples show entirely MgCu2-type Laves phase structure. The lattice parameter and Curie temperature increase with C content increasing. The magnetostriction at high magnetic field shows maximum value at x=0.05.

关键词： magnetostriction Pr0.15Tb0.3Dy0.55Fe1.85 Laves phase

Magnetostriction of Pseudobinary Compounds Pr_(0.15)Tb_xDy_(0.85-x)Fe_2(x=0 to 0.85)

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Journal of Materials Science & Technology 2000年第6期16卷 641-642页

作者： yangxian li Jingping QU Chengchun TANG Guangheng WU Wenshan ZHAN Hebei University of Technology Tianjin 300130 China State Key Laboratory for Magnetism Institute of Physics CAS BeiJing 100080 China

The compound ingots of Pr0.15TbxDy0.85-xFe2 (x=0 to 0.85) were prepared by arc melting in a water Cu boat using arc furnace under a purified Ar atmosphere. Appropriate annealing (850℃, 100 h) can obtain single Laves phase compound. The magnetostriction for these systems will rise obviously when partially substituted Tb or Dy by Pr.

关键词： x=0 to 0.85 Fe x)Fe2 x Magnetostriction of Pseudobinary Compounds Pr Pro

Defects in Fast-Neutron Irradiated Nitrogen-Doped Czochralski Silicon after Annealing at High Temperature

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Journal of Rare Earths 2006年第z1期24卷 91-93页

作者： liu lili li yangxian Ma Qiaoyun Chen Guifeng Sun Yong Yang Shuai School of Material Science and Engineering Hebei University of TechnologyTianjin 300130China

Fast-neutron irradiated nitrogen-doped Czochralski silicon(NCZ-Si)was annealed at 1100℃for different time,then FTIR and optical microscope were used to study the behavior of *** is found that[Oi]increase at the early stage then decrease along with the increasing of anneal *** density induced-defects can be found in the cleavage *** comparing NCZ-Si with Czochralski silicon(CZ-Si),[Oi]in NCZ-Si decrease more after anneal 24 h.

关键词： nitrogen-doped Czochralski silicon(NCZ-Si) neutron irradiation oxygen precipitation FTIR

Infrared studies of vacancy-oxygen-related complexes in electron-irradiated Czochralski-silicon

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Rare Metals 2006年第z2期25卷 55-58页

作者： CAI lili CHEN Hongjian li yangxian CHEN Guifeng li Xinghua HAO Jiangang ZHANG Yu School of Material Science and Engineering Hebei University of TechnologyTianjin 300130China Tianjin Institute of Technical Physics Tianjin 300130China

The oxygen-related defects in CZ silicon during electron irradiation(1.5 MeV)and subsequent annealing in the range of 150-600℃were investigated by means of *** the electron irradiation CZ-Si,vacancy-oxygen complex is one of the dominant defects and its concentration is proportional to electron dose but not related to oxygen *** this work,it was focused on the identification of the weak band at 860 cm^(-1)which was originated from asymmetrical stretching vibrations of an oxygen atom in the negative VO *** exhibits the same thermal stability with neutral VO band at 830 cm^(-1).In addition,the intensity of 889 cm-1 band has never been observed to exceed that of the A-center,implying that only a partial transformation of VO into VO_(2)does occur.

关键词： electron-irradiation VO FTIR irradiation defect

Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons

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Science China(Technological Sciences) 2004年第6期47卷 710-715页

作者： MENG Fanbin li yangxian liU Heyan QU Jingping liU Zhuhong CHEN Jinglian WU Guangheng School of Mechanical Science and Engineering Hebei University of TechnologyTianjin 300130China State Key Laboratory for Magnetism Institute of PhysicsChinese Academy of SciencesBeijing 100080China

The influence of stresses on martensitic transformation in Ni50Mn19Fe6Ga25 melt-spun ribbons was studied. X-ray diffraction examination shows that the ribbon has a pure cubic L21 phase at room temperature and that the ribbon surface exhibits [100] preferentially oriented texture, while the [110] axis is about 45° tilted from the normal of the ribbon. By calculating the d spacing at different angles with the length direction of the ribbon, the tension was observed. It was found that the direction of the stress was along [010] direction of the oriented textured grains. During cooling, there is no obvious structural transition observed in as-spun ribbons. However, when the ribbons were annealed at 900 K for 24 h, the tension along [010] direction disappeared and the structural transition from cubic to tetragonal occurred obviously during cooling. It indicates that it is the tension along [010] direction to suppress the martensitic transformation in the as-spun ribbons.

关键词： stress martensitic transformation ferromagnetic shape memory alloy

Growth of Czochralski silicon under magnetic field

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Science China(Technological Sciences) 2004年第3期47卷 281-292页

作者： XU Yuesheng liU Caichi WANG Haiyun ZHANG Weilian YANG Qingxin li yangxian REN Binyan liU Fugui Institute of Information Function Materials Hebei University of Technology Tianjin 300130 China

Growth of Czochralski (CZ) silicon crystals under the magnetic field induced by a cusp-shaped permanent magnet of NdFeB has been investigated. It is found that the mass transport in silicon melt was controlled by its diffusion while the magnetic intensity at the edge of a crucible was over 0.15 T. In comparison with the growth of conventional CZ silicon without magnetic field, the resistivity homogeneity of the CZ silicon under the magnetic field was improved. Furthermore, the Marangoni convection which has a significant influence on the control of oxygen concentration was observed on the surface of silicon melt. It is suggested that the crystal growth mechanism in magnetic field was similar to that in micro-gravity if a critical value was reached, named the growth of equivalent micro-gravity. The relationship of the equivalent micro-gravity and the magnetic intensity was derived as g=(v0/veff)g0. Finally, the orders of the equivalent micro-gravity corresponding to two crucibles with characteristic sizes were calculated.

关键词： Magnetic field equivalent micro-gravity diffusion-controlled mechanism Marangoni convection.

Synthesis and Magnetostriction of (Ce_xTb_(1-x))_(0.5)Pr_(0.5)Fe_2 Compounds

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Journal of Materials Science & Technology 2000年第2期16卷 179-180页

作者： yangxian li, Guizhi XU and Jingping QU (School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130, China) Chengchun TANG, Guangheng WU and Wenshan ZHAN (State Key Laboratory for Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China) School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China State Key Laboratory for Magnetism Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The structural and magnetostrictive properties of (CexTb1-x)0.5Pr0.5Fe_2 were investigated. Ceconcentration must exceed x=0.6 in order to obtain the pure Laves phase. The magnetostriction and anisotropy constant increase with the Tb-content in this system. The anisotropy value of PrFe_2 is lower than that of isostructural DyFe_2. From the X-ray step-scanned data we found that λ_111 of PrFe_2 is 1310x10^-6. A large increase of magnetostriction can be observed under a small prestress of 6 MP_a for Ce_0.5Pr_0.5Fe_2.

关键词： Synthesis and Magnetostriction of Ce_xTb Fe2 Compounds

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纳米磁性微粒(流体)的制备及性能

硅酸盐学报 2005年第11期33卷 1352-1355页

作者：汤庆国沈上越冉松林李养贤河北工业大学能源与环保材料研究所天津300130 中国地质大学材料科学与化学工程学院武汉430074

纳米磁性微粒(流体)是制备磁性无极或有极靶向药物载体的基本原料.用化学沉淀法成功合成出纳米磁性微粒(流体).用X射线衍射、透射电子显微镜对制备的磁性微粒进行了表征,测试了磁性微粒和流体的磁性能.研究表明:合成的磁性粒子主要成分... 详细信息

纳米磁性微粒(流体)是制备磁性无极或有极靶向药物载体的基本原料.用化学沉淀法成功合成出纳米磁性微粒(流体).用X射线衍射、透射电子显微镜对制备的磁性微粒进行了表征,测试了磁性微粒和流体的磁性能.研究表明:合成的磁性粒子主要成分为面心结构的反尖晶石Fe3O4,磁性颗粒的粒径一般为2～10 nm,以5 nm居多;纳米磁性液体性能稳定,长期放置不发生絮凝;纳米磁性微粒磁化率为0.32,纳米磁性流体磁化率为8.9×l0-3.该磁性材料磁响应力较强,剩磁较弱,属软磁性纳米材料.

关键词：纳米磁性微粒纳米磁性流体化学沉积法靶向药物载体磁化性能

一种基于图像处理技术的植物形态表型参数获取方法

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林业工程学报 2020年第6期5卷 128-136页

作者：李杨先张慧春杨旸南京林业大学机械电子工程学院南京210037

传统人工测量仪器提取植物形态表型参数的方式存在效率低、误差大、适用性弱、破坏性强等缺陷,成为制约植物表型研究发展的瓶颈。将模式树种杨树的姊妹种簸箕柳(Salix suchowensis Cheng)作为研究对象,设计了一套基于图像处理技术的植... 详细信息

传统人工测量仪器提取植物形态表型参数的方式存在效率低、误差大、适用性弱、破坏性强等缺陷,成为制约植物表型研究发展的瓶颈。将模式树种杨树的姊妹种簸箕柳(Salix suchowensis Cheng)作为研究对象,设计了一套基于图像处理技术的植物形态表型参数获取系统,通过高分辨率RGB相机获取植株的二维图像序列,基于HSV模型阈值分割方法实现簸箕柳与背景环境的分割,结合运动中恢复结构算法生成三维点云,并利用棋盘格进行坐标系间的距离转换。使用本系统提取簸箕柳的株高、基径、叶片面积、分枝数和分枝角等表型参数并与传统人工接触式测量值相比较,平均绝对百分比误差分别为7.69%,13.94%,9.99%,5.32%,9.30%。结果表明,本研究设计的植物形态表型参数获取系统能够较好地重建植物三维点云,并可快速、准确提取植物的形态表型参数,能够实现无损测量,满足研究对象簸箕柳三维形态表型参数的测量和生长观测的需求,可为植物尤其是林木表型研究提供数据参考。

关键词：簸箕柳形态表型参数图像处理三维点云无损测量