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Polar Coronal Holes During Solar Cycles 22 and 23

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Chinese journal of Astronomy and Astrophysics 2005年第5期5卷 531-538页

作者： jun zhang j. Woch S. Solanki National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Max-Planck-Institut fiir Sonnensystemforschung Katlenburg-Lindau D-37191 Germany

Data from the Solar Wind Ion Composition Spectrometer （SWICS） on Ulysses and synoptic maps from Kitt Peak are used to analyze the polar coronal holes of solar activity cycles 22 and 23 （from 1990 to end of 2003）. In the beginning of the declining phase of solar cycles 22 and 23, the north polar coronal holes （PCHs） appear about one year earlier than the ones in the south polar region. The solar wind velocity and the solar wind ionic charge composition exhibit a characteristic dependence on the solar wind source position within a PCH. From the center toward the boundary of a young PCH, the solar wind velocity decreases, coinciding with a shift of the ionic charge composition toward higher charge states. However, for an old PCH, the ionic charge composition does not show any obvious change, although the latitude evolution of the velocity is similar to that of a young PCH.

关键词： Sun: coronal - Sun: particle emission - Sun: solar wind

Synthesis and optical properties of nanosized CdS prepared in a quaternary CTAB/n-hexanol/n-heptane/water reverse micelle

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Chinese Science Bulletin 2001年第22期46卷 1873-1877页

作者： zhang, j Sun, LD Qian, C Liao, CS Yan, CH Peking Univ PKU HKU Joint Lab Rare Earth Mat & Bioinorgan Chem State Key Lab Rare Earth Mat Chem & Applicat Beijing 100871 Peoples R China

Quaternary water-in-oil reverse micelles consisting of cetyltrimethylammonium bromide (CTAB), n-hexanol, n-heptane and water were prepared and characterized. The optimized reaction conditions were determined, and monodispersed droplets of the reverse micelles were used as microreactors to synthesize CdS nanoparticles. By using transmission electron microscopy (TEM), UV-Vis spectroscopy and fluorescence spectroscopy, the influences of the reverse micelle components on the size, size distribution, morphology, stability and optical properties of CdS nanoparticles were investigated. CdS nanoparticles with narrow size distribution were obtained and the size range is 6-8 nm when W=24 (W=[water]/[CTAB]), F=5.27 (P=[n-hexanol]/ [CTAB]), [CTAB]=0.2 mol/L, [Cd2+] and [S2-] are 8.45×10-4 mol/L.

关键词： reverse micelles CdS nanoparticles optical properties.

Different Diffusion Behavior of Cu and Ni Undergoing Liquidesolid Electromigration

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journal of Materials Science & Technology 2014年第12期30卷 1235-1242页

作者： M.L.Huang Z.j.zhang H.T.Ma L.D.Chen Electronic Packaging Materials Laboratory School of Materials Science & Engineering Dalian University of Technology IC Packaging Department Xi'an Institute of Microelectronic Technology

The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（L-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 *** electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.

关键词： Cu/Sn/Ni Electromigration Cross-solder interaction Interfacial reaction Diffusion

Microstructure and Mechanical Properties of TiB_2/(Ni+Mo) Composites Fabricated by Hot Pressing

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journal of Materials Science & Technology 2000年第6期16卷 634-636页

作者： zhang j.Y. Fu Z.Y. Wang W.M. Wang H. Wuhan Univ. of Technol. Wuhan 430070 China

The fabrication of TiB2 ceramics with high performance at a relatively low temperature requires a second phase to assist the densification and control the microstructure. Moreover the interface characteristics of composites must also be considered. Nickel was chosen as a good metallic-bearing additive in this study. In order to optimize the interface, Mo was added. The results show that Mo can affect the interaction between TiB2 and Ni, and metallic liquid plays an important role in limiting the TiB2 grain growth in sintering.

关键词： NiMo Composites Fabricated by Hot Pressing Microstructure and Mechanical Properties of TiB2 Ni+Mo TiB

Experimental Study of the Temperature Distribution of Solar Collector Pavement

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武汉理工大学学报 2010年第17期32卷 227-230页

作者： zhang j Z WU S P CHEN M Y Key Laboratory of Silicate Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

Black asphalt road have excellent properties to collect the solar radiation and good use of asphalt absorb solar energy is a new energy technology. Asphalt is a sticky plastic material,its modulus and strength will change with temperature and the actual bearing capacity of pavement structure will change as well. A new method was used to evaluate the temperature change of asphalt pavement. By simulate solar radiation on asphalt sample to study the change of the temperature field. The temperature distribution of the asphalt concrete under the same light radiation and circulating water was also studied. The results indicate that this method can be a good simulation of solar collectors on the surface temperature field.

关键词： temperature field asphalt sample solar collector fluorescent lamp analog

Three principles for preparing Al wire with high strength and high electrical conductivity

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journal of Materials Science & Technology 2019年第5期35卷 742-751页

作者： j.P.Hou R.Li Q.Wang H.Y.Yu Z.j.zhang Q.Y.Chen H.Ma X.M.Wu X.W.Li Z.F.zhang Materials Fatigue and Fracture Division Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National Quality Supervision & Inspection Center of Electrical Equipment Safety Performance Zhejiang Huadian Equipment Testing Institute Hangzhou 310015 China Electric Power Research Institute of Liaoning Electric Power Co. Ltd. Liaoning Electric Power Co. Ltd. Shenyang 110006 China Department of Materials Physics and Chemistry School of Materials Science and Engineering Key Laboratory for Anisotropy and Texture of Materials Ministry of Education Northeastern University Shenyang 110819 China

The trade-off relation between the strength and the electrical conductivity has been a Iong-standing dilemma in metallic materials. In the study, three key principles, *** grains, sharp texture and nano-scale precipitates, were presented for preparing Al wire with high strength and high electrical conductivity based on the specially designed experiments for breaking the mutually exclusive relation between the strength and the electrical conductivity. The results show that the elongated grains could lead to a higher electrical conductivity in Al wire without sacrificing the strength;while, the sharp texture can efficiently strengthen the Al wire without influencing the electrical conductivity. Furthermore, nano-scale precipitates with proper size can simultaneously improve the strength and electrical conductivity of Al alloy wire. Under the guidance of the above three key principles, Al wires with high strength and high conductivity were prepared.

关键词： Al wire Texture Precipitates Strength Electrical conductivity

Formation of Re-containing Carbides in a Second Generation Directionally Solidified Ni Base Superalloy

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journal of Materials Science & Technology 2009年第3期25卷 361-364页

作者： T. Zhao D. Wang j. zhang G. Chen L.H. Lou School of Materials Science and Engineering Nanjing University of Science and Technology Nanjing 210094 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

The precipitates at grain boundary in a directionally solidified Ni base superalloy after heat treatment, aging at 975℃, and creep rupture test have been characterized. Besides the primary MC carbides and fine particles of u phase, the Re-containing M23C6 was observed. The precipitation kinetics revealed that the formation of M23C6 was associated with the dissolution of u phase and MC carbides. TEM image shows that the continuous precipitation of M23C6 particles effectively hinders the dislocation movement and strengthens the grain boundaries. The high strength of the alloy suggests that M23C6 carbides are beneficial to the properties although Re as an important matrix strengthening element was consumed.

关键词： Ni-base Superalloys Directional solidification Rhenium Carbide

CHARACTERIZATION OF Si_(1-x-y)Ge_xC_y FILMS GROWN BY ION IMPLANTATION AND SUBSEQUENT SOLID PHASE EPITAXY

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Acta Metallurgica Sinica(English Letters) 2002年第1期15卷 49-52页

作者： X.Q. Liu Y.Y. Wang W.j. Cheng j. zhang S.Y. Ma Dept. of Phys. Lanzhou Univ. Lanzhou 730000 China

Si1-x-yGexCy ternary alloy films were grown on monocrystalline silicon substrates by C+ ion implantation and subsequent solid phase epitaxy (SPE). Two-step annealing technique was employed in the SPE. The structure and electrical properties of the alloy films were determined using Fourier transform infrared spectroscopy and van der Pauw Hall measurements, respectively. With the optimization of two-step annealing technique for the implanted Si1-x-yGexCy layers, a certain amount of C atoms occupied substitutional sites and no SiC was formed.

关键词： Si1-x-yGexCu film ion implantation SPE

Phase stability,elastic properties and electronic structures of Mg-Y intermetallics from first-principles calculations

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journal of Magnesium and Alloys 2015年第2期3卷 127-133页

作者： j.zhang C.Mao C.G.Long j.Chen K.Tang M.j.zhang P.Peng Key Laboratory of Lightweight and Reliability Technology for Engineering Vehicle The Education Department of Hunan ProvinceChangsha University of Science and TechnologyChangsha 410114China Key Laboratory of Efficient and Clean Energy Utilization College of Hunan ProvinceChangsha University of Science and TechnologyChangsha 410114China College of Materials Science and Engineering Hunan UniversityChangsha 410082China

The phase stability,elastic properties and electronic structures of three typical Mg-Y intermetallics including Mg_(24)Y_(5),Mg_(2)Y and MgY are systematically investigated using first-principles calculations based on density functional *** optimized structural parameters including lattice constants and atomic coordinates are in good agreement with experimental *** calculated cohesive energies and formation enthalpies show that either phase stability or alloying ability of the three intermetallics is gradually enhanced with increasing Y *** single-crystal elastic constants C_(ij) of Mg-Y intermetallics are also calculated,and the bulk modulus B,shear modulus G,Young's modulus E,Poisson ratio v and anisotropy factor A of polycrystalline materials are *** is suggested that the resistances to volume and shear deformation as well as the stiffness of the three intermetallics are raised with increasing Y ***,these intermetallics all exhibit ductile characteristics,and they are isotropic in compression but anisotropic to a certain degree in shear and ***,Mg_(24)Y_(5) presents a relatively higher ductility,while MgY has a relatively stronger anisotropy in shear and *** analysis of electronic structures indicates that the phase stability of Mg-Y intermetallics is closely related with their bonding electrons numbers below Fermi ***,the more bonding electrons number below Fermi level corresponds to the higher structural stability of Mg-Y intermetallics.

关键词： Magnesium alloys Intermetallics Phase stability Elastic properties Electronic structure