Applied Mechanics and Materials Vols. 275-277

Abstract: The experiment of mechanical characteristics of sliding contact in nano-scale was researched using nano-indenter. The displacement-friction curves with different loads and sliding velocities were given through the contact effect between diamond indenter and mono-crystalline silicon test-coupon. The three-dimensional AFM morphologies were obtained through scanning contact area by AFM. The research shows that the contact-force and friction increase along with the increment of loads, in condition of sliding with different loads. The friction increases along with the increment of sliding velocity, in condition of different sliding velocities. Otherwise, furrow destruction along with obvious plastic flow is generated with low sliding velocity (100μm/s). However, the oddments accumulate obviously on the verge of nick with high sliding velocity (above 100μm/s), and the phenomenon of oddments accumulating is more obvious along with the increment of sliding velocity.

Abstract: Neodymium zirconate nanocrystals doped aluminium ion Nd_xAl_2-xZr₂O₇ with pyrochlore structure were prepared by a salt-assistant glycine combustion method. Zirconium nitrate, aluminium nitrate and neodymium nitrate were used as chemicals, and glycine was used as burning agent. The as-prepared Nd_xAl_2-xZr₂O₇ nano-crystals were characterized by XRD, FT-IR, TEM and HRTEM. The results showed the Nd ions can be partially replaced by Al ions. For crystalline Nd_1.9Al_0.1Zr₂O₇, there are four strong diffraction peaks at 2θ = 29.02°, 33.70°, 48.37° and 57.37° corresponding crystal faces are 0.308nm, 0.266nm, 0.188nm and 0.161 nm, respectively, which indicates that the interstices of corresponding crystal faces are smaller than that of Nd₂Zr₂O₇. Furthermore, the fluorescent properties of Nd_1.9Al_0.1Zr₂O₇ nano-crystals evaluated by the fluorescence spectra indicate that the prepared nano-crystals are a kind of potential fluorescent-emitted material.

Abstract: Coarse-grained molecular dynamics simulations on self-assembly behavior of diblock copolymers (DCP) with nanoparticles confined in cylindrical nanopores are perfomed to study the morphology transition of DCP affected by the confined ratio of the cylindrical confinement diameter to the block copolymer domain spacing, the wall-polymer interactions, the particle-polymer interaction potential and the component concentration. The simulation results show that nanoparticles have a pronounced effect on the morphology transition of DCP and can therefore be considered as an important aspect in controlling the confined self-assembly in cylindrical confinement. Besides, the phase diagram indicates the process of morphology transition.

Abstract: A noncovalent method was presented in order to improve the solubility of multi-walled carbon nanotubes (MWCNTs) in water. Poly (ε-benzyloxycarbonyl-L-lysine) (PZLL) was prepared by ring-opening polymerization of ε-carbobenzoxy-L-lysine N-carboxyanhydride (Z-L-Lys NCA). After the removal of the benzyloxycarbonyl group, water-soluble poly-L-lysine (PLL) was obtained. The structure of PZLL and PLL was characterized by FTIR and 1H NMR. Dispersion of MWCNTs in the water solution of PLL was investigated by ultraviolet spectrophotometer and visual inspection. When the mass ratio of MWCNTs to PLL is 1:50 and the pH value of the water solution of PLL is 5, MWCNTs can be well dispersed in water.

Abstract: Multi-walled carbon nanotube (MWCNT) reinforced copper nanocomposites were prepared using a unique spherical MWCNT-implanted copper composite powders. The MWCNTs are homogenously ‘locked’ in the composite and tightly bonded to the matrix, which makes them play excellent reinforcement role on the microhardness compared with the unreinforced pure copper. Although the thermal conductivity is not enhanced for the thermal resistance between the carbon nanotubes and the copper matrix; it is still high enough to be used as electronic packaging materials even the concentration of MWCNTS in the composite is up to 5 wt%. Furthermore, the thermal expansion of the composites decreased apparently with the addition of the carbon nanotubes.

Abstract: High-quality carbon nanotube (CNT) arrays have been synthesized through a chemical vapor deposition process. The Fe/Al₂O₃ on silicon was used as the catalyst, ethylene as the carbon source, and a mixture gas of Ar and H₂ gases as the carrying gas. With spinnable CNT arrary as initial materials, aligned carbon nanotube fibers were continuously fabricated by dry spinning. And then we study the excellent mechanical property of the carbon nanotube fibers.

Abstract: Uniform growth of WO3 with macroscopic structures was successfully achieved by using carbon nanofibers (CNFs) as template. Field emission scanning electron microscopy (FE-SEM), coupled with X-ray diffraction (XRD) analysis confirmed the template effect and the existence of WO3 immobilized on the macroscopic silica fiber.

Abstract: Due to its unique mechanical，electrical，optical，chemical，catalytic and biological properties, nano-scale materials such as metal nanorods, have attracted wide attention. In these low-dimensional systems， Cu nanorods are ideal systems in novel electronic nano-devices and nano-catalysis. Nowadays the research of Cu nanorod has already become one of the central subjects in the nanomaterials science.In this paper, molecular dynamics simulations have been used to study structural changes of Cu nanorod during heating within the framework of embedded atom method (EAM) at the atomic scale，and their dynamics are also studied. During continuously heating processes, by studying the structure of the metal nanorods on the pair distribution function and energy changes，they are studied for the structural changes and dynamic properties of the Cu nanorods.The simulation results show that continuous changes of the Cu nanorods upon heating. At low temperatures, both the Cu nanorods have ordered arrangements with face-centered cubic structures. With increasing the temperature，the atom arrangements present the changes from the ordered state into the disordered state. It is also found that the size and shape of the nanorods have effect on the structural changes of these nanorods in the heating processes. The results show that the initial geometry of the nanorods greatly affect the structural change processes.

Abstract: It nanometer is today one of the hot areas of research,through electrodeposition method manufacturing Orderly structure With metal and semiconductor properties, Micron from the magnitude of nanotechnology potential direct impact on the distribution of morphology,So conductive pushing the situation on the potential distribution is particularly important.This means using mathematical derivation of the potential distribution of analytical expressions,A reasonable explanation of the prospective growth of 2 dimensional nanostructures structure morphology,The theoretical analysis for the future laid the foundation.

Abstract: The effect of local molecular structural cavity defect on the atom frequencies of bonded atoms is investigated in this study. The molecular dynamic (MD) simulation method is used to simulate the variation of atom frequency near by the cavity defect in a carbon diamond structure. The potential energy model, i.e. the second-generation reactive empirical bond order (REBO) potential function, is employed to derive the dynamic interaction between bonded atoms. The effect of local defect on the vibration amplitude and the density of state (DOS) is studied. The simulated results indicate that the local defect may affect the dynamic behavior of atoms near the local cavity defect significantly.