Papers by Author: Tao Sun

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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: 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.
Authors: Guo An Hou, Tao Sun
Abstract: This paper discusses the design and analysis of a direct-drive linear slide used linear mortor. The alloy steel carriage is fully floated by twelve hydrostatic bearings, and it is force-closed. It has very high stiffnesses, 1700N/mm in vertical direction and 690N/mm in horizontal direction. The working stroke of slide is 200 mm. The slide is driven by a ironless linear motor. The optic linear encoder was used for the measurements and feedback. To analyze the static and dynamic performance of the slide, the modelling and simulation process, using the finite element analysis method, is presented.
Authors: Yan Bo Feng, Tao Sun
Abstract: In recent years, wire sawing is considered to be a potentially better technology of slicing brittle crystals especially semiconductor, owing to the unmatched advantages of slicing large ingot into thin wafers with high efficiency, fine quality and less kerf loss. This paper analyses the dynamic effect on wire from a variety of excitation and mechanical structure in the process of cutting on the basis of the effects of vibration on slicing wafer quality. A suitable model is built according to Hamilton principle, closed form expressions is present for the steady state response using finite element method. The relation between inherent characteristics of wiresaw and different system parameters is obtained.
Authors: Yan Bo Feng, Tao Sun
Abstract: Multi wire saw is the important basis of integrate circuit, optoelectronic, photovoltaic industry, and it becomes a promising technology for semiconductor wafer production because of its advantage of slicing large ingot into thin wafers with high efficiency and good quality. In the process of moving, the inevitable wiresaw vibration is directly related to the whole process with both benefit and harm. This paper analyses the wire vibration behavior in cutting area, the dynamic model is built by modeling the interaction between the dynamics of wire and hydrodynamic characteristics of slurry flow, available modal analysis provides closed form expressions for the steady state response, obtain the vibration of wire subject to different process parameters on wire saw manufacturing process.
Authors: Shen Dong, Xiao Li Zhao, Jing He Wang, Zheng Qiang Li, Tao Sun, Ying Chun Liang
Abstract: Here a simple and direct method based on transfer printing has beep developed, in which rigid stamps transfer metal films deposited on the relief surface of the stamps onto patterned organic substrates. Ultra-precision machining technology is combined with conventional photolithography to fabricate patterned Si stamps and organic substrates by replica molding. Experiment results indicate that patterned metal films on Silicon stamps were successfully transferred onto PDMS substrates. Fabrication of patterned metal films on organic substrates by transfer printing may suit for fabricating sub-micrometer and nanometer scale features in a single process.
Authors: Xiong Fei Zheng, Wen Jie Zhai, Tao Sun, Ying Chun Liang
Abstract: A completely interconnected macroporous and microporous poly(l-lactic acid) (PLLA) scaffold was fabricated from a PLLA–dioxane–water ternary system by an advanced manufacturing technology called low-temperature deposition manufacturing. A proper fraction of water and PEG added into the polymer solution induces liquid-liquid phase separation and gelation. The liquid-liquid phase separation brings in a new micro morphology and gelation effect produces higher fabrication accuracy.
Authors: Zeng Qiang Li, Tao Sun, Yong Da Yan, Jun Jie Zhang, Ying Chun Liang, Shen Dong
Abstract: Molecular dynamics is a rapidly developing field of science and has become an established tool for studying the dynamic behavior of material machining. A three-dimensional molecular dynamics (MD) model about the atoms of the diamond cutting tools and the diamond grits is built by using the molecular dynamics. The Tersoff potential function is used to calculate the force and potential energy among the atoms of the diamond tools and the atoms of the diamond grits. The lapping processes at a special cutting depth are simulated. The variety of the specimen potential energy in the lapping process is observed. The mechanism of the diamond micro machining and the form of the surface formation are given by comparing the distribution maps of atoms in initial and cutting states. This study will give a strong support to the diamond cutting tools’ lapping.
Authors: Yong Da Yan, Tao Sun, Shen Dong, Ying Chun Liang
Abstract: A three dimensional molecular dynamics model is employed to simulate AFM-based lithography process. To investigate effects of tip geometry, three kinds of tip models are proposed: a cone-shape tip with a hemisphere at the end, a round-edged three sided pyramid tip with a hemisphere at the end and a sharp-edged three sided pyramid tip. These models simulate scratching behaviors of AFM tip at different scratching depths. Results showed that materials removal behavior and scratching forces were significantly affected by tip geometry, depending on the scratching depth and scratching directions. The specific energy using a sharp-edged three sided pyramid tip displayed a different behavior comparing to that using a round-edged three sided pyramid. However, scratching orientations exhibited no effects on the specific energy.
Authors: Qing Liang Zhao, Guang Yu, Tao Sun, Shen Dong
Abstract: An advanced conditioning technique was developed to precisely and effectively condition the nickel electroplated mono-layer coarse-grained diamond grinding wheel of 46m and 91m grain size with an aim to fabricate Diamond Micro Tool Arrays (DMTA), to meet the high demands of form accuracy, surface quality and low subsurface damage in ductile machining of silicon carbide (SiC). The precision machining experiments on SiC were carried out on a precision grinder to determine the applicability of these fabricated diamond micro tool array (DMTA). The experimental result indicates that the newly developed DMTA is applicable and feasible to realize ductile machining on SiC with high efficiency and low diamond tool wear rate, which shows a good prospect to apply this new concept diamond tool type in precision machining of SiC, as well as the other brittle and hard-to-machine materials.
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