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Beryllium Surface Modified by B Ion Implantation

HU Renyuan YANG Yushi Institute of Low Energy Physics , Beijing Normal University , China. Beijing Research Institute of Materials and Technology , China.

材料科学技术（英文）

Beryllium is implanted with 100 keV, 2×10~(17) B/cm~2 and post-implanted sample is annealed at 650℃ for 1 h.Hardness measurement indicates that the hardness increases with implantation and can further be modified by post-implantation heat treatment. Profile measurement shows that implantation causes contamination on the surface of beryllium. During annealing boron diffuses out of beryllium and carbon on surface diffuses into beryllium. Beryllium surface is modified by composition change and carbide formation.

关键词: ion implantation , null , null

Guangzhou Institute of Energy Conversion,The Chinese Academy of Sciences,Guangzhou 510070,China

B.W. Wang , H. Shen

金属学报(英文版)

Ni-Cr System solar selective thin solid films were prepared by d.c. magnetron reactivesputtering under the atmosphere of O2 and N2. Ni-Cr alloy was chosen as targetmaterial and copper sheets as substrate. Using SEM, Spectrophotometer and Talystepto analyze the relations between the selective characteristic and the structure, theformation and the thickness of the thin films. The aim is to obtain good solar selectivethin films with high absorptance and low emittance, which is applied to flat plate solarheat collectors.

关键词: solar selective thin film , null , null , null

Strong magnetoelectric coupling in Tb-Fe/Pb(Zr(0.52)Ti(0.48))O(3) thin-film heterostructure prepared by low energy cluster beam deposition

Applied Physics Letters

The magnetoelectric Tb-Fe/Pb(Zr(0.52)Ti(0.48))O(3) thin-film heterostructure was prepared by low energy cluster beam deposition. The microstructures, ferroelectric property, leakage current, and magnetization, as well as magnetoelectric effect were investigated for the heterostructure. It is shown that the thin-film heterostructure displays the well-defined microstructure with clear interface. The heterostructure not only exhibits good ferromagnetic and ferroelectric properties, but also possesses strong magnetoelectric effect. The present work provides an ideal avenue to prepare magnetoelectric composite films and facilitates their applications on the microelectromechanical system devices. (C) 2008 American Institute of Physics.

关键词: composites

LOW ENERGY DISLOCATION STRUCTURES DUE TO FATIGUE SOFTENING

CHAI Huifen WANG Liqin Xi'an Jiaotong Uuiversity , Xi'an , ChinaLAIRD Campell University of Pennsylvania , U.S.A.[Originally published in ACTA METALL SIN(CHINESE EDN)25(3)1989 pp A201—A206 , Associate professor , Xi'an Jiaotong University , Xi'an , China

金属学报(英文版)

The evolution of dislocation structures in 6% prestrained steel 1018 during fatigue has been studied by TEM.The dislocations are quite movable,the loose cells quickly change to “checkboard”structures,in which the main cell walls lie about {100}.Then,the low energy dislocation structures i.e.dipolar walls and abyrinth structures are evolved.The characteristic of labyrinth and the orientation of dipolar walls are quite similar to fcc crystal.This indicates the energy state of system and the moving ability of dislocations are important factors affect- ing softening process,rather than the slip geometric characteristic of dislocations and details of dislocations.The decreasing in misorientation between adjoining cells and internal stress are discussed.

关键词: steel 1018 , null , null

Low energy ion channelling in single-wall nanotubes

Chinese Physics Letters

Monte Carlo simulation is used to study the low energy He ion challenging in a (17,0) single-wall nanotube and its rope. The simulation shows that the channelling critical angle Psi(C) = 48E(-1/2) (E is incident energy) for a 1.31-nm-diameter initial beam into the nanotube, while Psi(C) = 45E(-1/2) for the 1.31-nm-diameter initial beam into its rope.

关键词: charged-particles;field emission;carbon;diffraction;crystals;atoms

Low Energy Dislocation Structure in Deformed Metals

DIAO Xiaoxue XING Xiusan ** Department of Applied Physics , Beijing Institute of Science and Technology , Beijing , 100081 , China.To whom correspondence should be addressed.

材料科学技术（英文）

In this paper,the dislocation distribution struc- ture in deformed metal is discussed.The flow stress of material for the heterogeneous dislocation distri- bution which tends to the flow stress for the homo- geneous dislocation distribution in the limiting case is derived.The causes and the effects of the long range internal stresses are discussed.The total deformation energy of material system is obtained and the trend of evolution of dislocation distribu- tion in deformed metals is discussed simultaneously. No micromechanisms of dislocations are involved in the discussion,therefore the theory developed in this paper is universal.

关键词: Dislocation structure , null

Isotopic mass effects for low-energy channeling in a silicon crystal

Radiation Effects and Defects in Solids

Monte Carlo (MC) simulations have been used to study the low-energy channeling of (10)B and (11)B ions along the [100] axis in Si crystal. MC simulations show that the critical angle Psi(C) approximate to 15.3(keV/E)(1/2) (in degrees) for the channeling of isotopic (10)B ions and Psi(C) = 14.5(keV/E)(1/2) (in degrees) for the channeling of isotopic (11)B ions, where E is the incident energy. This means that (Psi(C) (for 10B ions)/Psi(C for 11B ions)) approximate to (15.3/14.5) approximate to (11/10)(1/2).

关键词: mass effect;channeling;silicon crystal;single-wall nanotubes;carbon nanotubes;charged-particles;molecular-dynamics;critical angles;heavy-ions;dependence;atoms;distributions;radiation

Channeling of low energy light and heavy ions in single-wall nanotubes

Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms

The Monte Carlo simulation program has been used to study low energy channeling in the single-wall nanotube and its rope, in comparisons between beam sizes and between light (He) and heavy (Ar) ions. The simulation mainly shows that the critical angle Psi(C) = 48 E-1/2 (E is incident energy) for the He (light) ion channeling but Psi(C) = 18 E-1/2 for the Ar (heavy) ion channeling, in the (17,0) zigzag single-wall nanotube. Thus, it might be found in the simulation that Psi(C) strongly depends on the ion mass. (C) 2007 Elsevier B.V. All rights reserved.

关键词: the Monte Carlo simulation;channeling;nanotube;charged-particles;carbon nanotubes;diffraction;crystal;atoms

Ion mass dependence for low energy channeling in single-wall nanotubes

Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms

An Monte Carlo (MC) simulation program has been used to study ion mass dependence for the low energy channeling of natural- and pseudo-Ar ions in single-wall nanotubes. The MC simulations show that the channeling critical angle Psi(C) obeys the (E) (- 1/2) and the (M-1) (- 1/2) rules, where E is the incident energy and M-1 is the ion mass. The reason for this may be that the motion of the channeled (or de-channeled) ions should be correlated with both the incident energy E and the incident momentum (2M(1)E)(1/2), in order to obey the conservation of energy and momentum. (c) 2008 Elsevier B.V. All rights reserved.

关键词: mass regulation;nanotubes;channeling;Monte Carlo simulation;charged-particles;carbon nanotubes;heavy-ions;simulation;crystal;atoms