Q.L.Deng1)
,
W.D.Huang1)
,
Y.H.Zhou1)
,
C.Y.Yu2)
,
Y.K.Zhang2)
,
Y.X.Tang2) and H.Zhang2) 1) State Key Lab .of Solidification Processing
,
Northwestern Polytechnical University
,
Xi’an 710072
,
China 2) Mechanical Department
,
Nanjing University of Aeronautics & Astronautics
,
Nanjing 210016
,
China
金属学报(英文版)
The mechanism oflasershock processing wasanalyzedinthispaper. Westudyexperimentallythelasershock processingon 2024 T62 aviation aluminium alloys. Theexperimental results show thefatiguelife of 2024 T62 aviation aluminium alloysshocked by a laserisimprovedgreatly.
关键词:
lasershock processing
,
null
,
null
Nanostructured Materials
The Landauer electrical resistivity R of one-dimensional (1D) layered nanostructures is calculated. The analysis of the logarithm of the resistance as a function of grain size reveals that there is a minimum value of resistivity R(min) when the grain size takes a value of d(c), where d(c) depends on the barrier height and excess volume of interface. R increases in the region of d(cl) > d > d(c), where d is the grain size, and d(cl) is another critical value of grain size. The mechanism of the anomalous resistivity behavior is discussed briefly.
关键词:
nanocrystalline;resistance;alloys
Guozhen SHEN
,
Di CHEN
材料科学技术（英文）
One-dimensional (1-D) nanostructures have been attracted much attention as a result of their exceptional properties, which are different from bulk materials. Among 1-D nanostructures, 1-D heterostructures with modulated compositions and interfaces have recently become of particular interest with respect to potential applications in nanoscale building blocks of future optoelectronic devices and systems. Many kinds of methods have been developed for the synthesis of 1-D nanoscale heterostructures. This article reviews the most recent development, with an emphasize on our own recent efforts, on 1-D nanoscale heterostructures, especially those synthesized from the vapor deposition methods, in which all the reactive precursors are mixed together in the reaction chamber. Three types of 1-D nanoscale heterostructures, defined from their morphologies characteristics, are discussed in detail, which include 1-D co-axial core-shell heterostructures, 1-D segmented heterostructures and hierarchical heterostructures. This article begins with a brief survey of various methods that have been developed for synthesizing 1-D nanoscale heterostructures and then mainly focuses on the synthesis, structures and properties of the above three types of nanoscale heterostructures. Finally, this review concludes with personal views towards the topic of 1-D nanoscale heterostructures.
关键词:
Nanostructures
,
Heterostructures
,
One-dime
徐江
,
揭晓华
,
段桂生
电镀与精饰
doi:10.3969/j.issn.1001-3849.1999.03.010
对Ni-W(D)刷镀层进行热处理,测量了热处理前后镀层硬度的变化,并利用X-射线衍射,对刷镀Ni-W(D)镀层再强化机理作了研究.在摩擦磨损实验中,利用了电子探针,对磨损前后镀层成分进行了分析,探讨了造成成分变化的原因,主要是W朝磨损区偏聚.
关键词:
Ni-W(D)刷镀层
,
再强化
,
偏聚
Xiaosheng FANG
材料科学技术（英文）
One-dimensional (1D) nanomaterials and nanostructures have received much attention due to their potential interest for understanding fundamental physical concepts and for applications in constructing nanoscale electric and optoelectronic devices. Zinc sulfide (ZnS) is an important semiconductor compound of II-VI group, and the synthesis of 1D ZnS nanomaterials and nanostructures has been of growing interest owing to their promising application in nanoscale optoelectronic devices. This paper reviews the recent progress on 1D ZnS nanomaterials and nanostructures, including nanowires, nanowire arrays, nanorods, nanobelts or nanoribbons, nanocables, and hierarchical nanostructures etc. This article begins with a survey of various methods that have been developed for generating 1D nanomaterials and nanostructures, and then mainly focuses on structures, synthesis, characterization, formation mechanisms and optical property tuning, and luminescence mechanisms of 1D ZnS nanomaterials and nanostructures. Finally, this review concludes with personal views towards future research on 1D ZnS nanomaterials and nanostructures.
关键词:
One-dimensional
,
ZnS
,
Nanomaterials
,
Nanost
Zhaoyang ZENG
,
Lide ZHANG
,
Xiaohong YAN
材料科学技术（英文）
Ballistic transport of Q1D electrons through multiple magnetic barriers is investigated. It is shown that ballistic conductance peaks disappear progressively with the increase of the oscillation frequency of the confining parabolic potential.
关键词:
Journal of Applied Physics
The alloying effect of 3d transition metal elements on the lattice constants and their site preferences in gamma'-Co(3)(Al, W) are systematically studied based on a supercell model. The lattice constant of the gamma' phase is modified by the addition of 3d transition metal elements, and it increases in the order of Fe < Ni < Mn < Cr < V < Ti. Four types of site preference are identified for these 3d elements in gamma' phase by analyzing the binding energy and the impurity formation energy. Ni, Fe, V, and Ti are recognized to stabilize the gamma' phase. Their distinct alloying effect is further revealed by investigating the impurity-induced charge density difference and the partial density of states. These results are in agreement with the experimental data ever reported. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3319650]
关键词:
augmented-wave method;co-base superalloy;electronic-structure;site;preference;ni3al;phase;temperature;stability;magnetism;alloys
赵峰
,
杨志懋
,
丁秉钧
稀有金属材料与工程
为节约Cr资源,提高CuCr触头材料的耐电击穿性能并满足其大规模生产的需要,根据W、Co的选择相强化作用, 以纯Cu、Cr块为原料, 采用Ar气保护熔炼法制备CuCr25W1Col触头合金,并对其性能进行研究.实验结果表明,该合金晶粒尺寸细小,含气量低,耐电压强度已达到常规触头材料的水平.
关键词:
CuCr触头材料
,
选择相强化
,
耐电压强度
Journal of Physical Chemistry B
Size-controlled gold nanocrystals were conveniently synthesized through direct electroreduction of bulk AuCl4- ions in the presence of poly(N-vinylpyrrolidone) (PVP). PVP greatly enhanced the gold particle formation process and also significantly retarded the gold electrodeposition process, allowing the electrochemical synthesis of gold nanocrystals to be carried out in the form of simple electroreduction. This novel electrochemical method may be extended to synthesis of other noble metal nanoparticles with controllable size on a large scale. The PVPK90-protected gold nanocry.stals spontaneously self-assembled into nearly ordered 2D close-packed arrays and interesting 1D nanostructures. The aggregation of unstable PVPK17-protected gold nanocrystals resulted in the formation of ultrathin single-crystalline films. PVP plays multifunctional roles in controlling the size and shape of gold nanocrystals and in inducing individual gold nanocrystals to construct ID nanostructures. The nanoparticle self-assembling technique based on PVP offers a simple, but effective, path to organize individual gold nanoparticles into various 1D and 2D nanostructured materials.
关键词:
shape-controlled synthesis;uniform silver nanowires;optical-properties;size control;nanoparticles;nanorods;transition;mechanism;nanomaterials;microscopy
