Papers by Author: Shen Dong

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Authors: Bo Wen Zhang, Yong Da Yan, Zhen Jiang Hu, Xue Sen Zhao, Ying Chun Liang, Wei Dong Fei, Shen Dong
Abstract: As the dimensions of parts become smaller, understanding the mechanical properties of these small components was becoming more important. Till present day, the methods and technology used to investigate the deformation behavior in nanoscale were still lacking. In this paper, the specimens were single crystal copper wires with diameter in 50 microns. Atomic force microscope integrated with an in- situ tensile system were used to determine the mechanical behavior of copper wires and observe the surface topography deformation in nanoscale simultaneously. The results were as follows: the modulus of elasticity, tensile strength and failure strain of the sample were 167Gpa, 0.564GPa and 0.011, respectively. By using AFM, the separation process between the copper wire and impurities on it, such as oxide film, was observed. The nanoscale deformation process of the copper wire was also obtained.
Authors: Xiao Li Zhao, Shen Dong, Ying Chun Liang, T. Sun, Yong Da Yan
Abstract: Atom Force Microscopy (AFM) can be employed to create surfaces in Si substrate with recessed features. The resulting patterns can serve as masters to make the required elastomeric stamps for soft lithography. Morphology analysis of patterned features on Si substrate and polydimethylsiloxane (PDMS) stamp by AFM imaging confirms that pattern can be successfully transferred from Si substrates to PDMS stamps. It is shown that this method for creating masters can be performed with an AFM, making this method particularly straightforward, economical and accessible to a large technical community that are provided with AFM for measurement.
Authors: Yong Da Yan, T. Sun, Shen Dong, Ying Chun Liang, K. Cheng
Authors: J.Z. Zhang, Dan Li, Ming Jun Chen, Shen Dong
Authors: Bo Wang, Qing Liang Zhao, Lang Ping Wang, Shen Dong
Abstract: This paper presents a novel, rapid and damage-free method to polish the ultra-smooth surface of the SiC optics. First, the basic philosophy of this method is introduced, which uses the active radicals got from CF4 in the atmospheric pressure plasma zone to react with the SiC material at the optics surface to generate the vaporization of SiF4. Then, the design of the atmospheric pressure plasma jet and the corresponding prototyping polishing facility are introduced. The theoretical analysis on the necessary conditions to generate the excited radicals is also presented in this part. To verify the effectiveness of this novel polishing method, experiments on the generation of atmospheric pressure plasma and the SiC optics polishing are carried out with our prototyping facility. The experiment results show that plasma discharge is stable at the atmospheric pressure and sub-nanometer roughness of the polished SiC surface can be obtained.
Authors: Yong Zhi Cao, Shen Dong, Ying Chun Liang, Tao Sun, Yong Da Yan
Abstract: Ultrathin block copolymer films are promising candidates for bottom-up nanotemplates in hybrid organic-inorganic electronic, optical, and magnetic devices. Key to many future applications is the long range ordering and precise placement of the phase-separated nanoscale domains. In this paper, a combined top-down/bottom-up hierarchical approach is presented on how to fabricate massive arrays of aligned nanoscale domains by means of the self-assembly of asymmetric poly (styrene-block-ethylene/butylenes-block-styrene) (SEBS) tirblock copolymers in confinement. The periodic arrays of the poly domains were orientated via the introduction of AFM micromachining technique as a tool for locally controlling the self-assembly process of triblock copolymers by the topography of the silicon nitride substrate. Using the controlled movement of 2- dimensional precision stage and the micro pressure force between the tip and the surface by computer control system, an artificial topographic pattern on the substrate can be fabricated precisely. Coupled with solvent annealing technique to direct the assembly of block copolymer, this method provides new routes for fabricating ordered nanostructure. This graphoepitaxial methodology can be exploited in hybrid hard/soft condensed matter systems for a variety of applications. Moreover, Pairing top-down and bottom-up techniques is a promising, and perhaps necessary, bridge between the parallel self-assembly of molecules and the structural control of current technology.
Authors: Zong Wei Xu, Ying Chun Liang, Shen Dong, Li Qiang Gu, T. Sun, Qing Liang Zhao
Abstract: An improved arc welding method was developed to fabricate carbon nanotube probe under direct view of optical microscope. The new fabrication method here needs not coat silicon probe in advance with metal film, which greatly reduces the fabrication’s difficulty. An easy method for shortening the nanotube probe was also developed. The improved fabrication method here is simple and reliable. The fabricated carbon nanotube probe showed good properties of higher length-to-diameter aspect ratio, better wear characteristics than silicon probe.
Authors: Yu Quan Chen, Shen Dong, X.C. Xu, Y.C. Guan, A.A. Kossobutski
Authors: Jing He Wang, Ming Jun Chen, Shen Dong, H.X. Wang, J.H. Zhang, Wen Jun Zong
Abstract: In this paper, mechanical characteristics of KDP crystal anisotropy are analysed theoretically. Vickers indentation experiments are adopted to validate the variation rule of hardness and fracture toughness in different orientation of KDP crystal plane (100), and a model to calculate critical cutting thickness of brittle-ductile transition is proposed for the KDP crystals. The result shows that, on the crystal plane (100), the minimum value of critical cutting thickness of KDP crystal in brittle-ductile transition appears in the direction [110], but the maximum appears in the direction [010]. Finally, the ultra-precision machining of KDP crystal is performed, and the results agree well with the theoretical conclusions. Super-smooth surface with a roughness RMS of 6.6nm is reached as machined in the crystal direction [010], and 11.2nm to the direction [110].
Authors: Zhen Jiang Hu, Yong Da Yan, Tao Sun, Shen Dong, Z.Z. Zhao
Abstract: The equations correlated the normal load and the tip penetration depth were derived through the theoretical analysis of the penetration process of the diamond tip. Verified by experiments, the equations can reflect the penetration process of the scratching machining system and provide theoretical basis for the optimization of depth control algorithm. The control of scratching depth realized in AFM deflection mode can effectively restrain the system drift during scratching process.
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