Polymer materials such as transparent thermoplastic poly(methyl methacrylate)(PMMA)have been of great interest in the research and development of integrated circuits and micro-electromechanical systems due to their re...Polymer materials such as transparent thermoplastic poly(methyl methacrylate)(PMMA)have been of great interest in the research and development of integrated circuits and micro-electromechanical systems due to their relatively low cost and easy process.We fabricated PMMA-based polymer hollow microneedle arrays by maskdragging and aligning x-ray lithography.Techniques for 3D micromachining by direct lithography using x-rays are developed.These techniques are based on using image projection in which the x-ray is used to illuminate an appropriate gold pattern on a polyimide film mask.The mask is imaged onto the PMMA sample.A pattern with an area of up to 100×100 mm^(2)can be fabricated with sub-micron resolution and a highly accurate order of a few microns by using a dragging mask.The fabrication technology has several advantages,such as forming complex 3D micro structures,high throughput and low cost.展开更多
Molecular dynamics simulation has been performed to determine the infinite-dilution diffusion coefficients of oxygen and nitrogen, and the diffusion coefficients of NaCl in supercritical water from 703.2-763.2 K and 3...Molecular dynamics simulation has been performed to determine the infinite-dilution diffusion coefficients of oxygen and nitrogen, and the diffusion coefficients of NaCl in supercritical water from 703.2-763.2 K and 30-45 MPa. The results obtained show that the diffusion coefficients in supercritical water increase with temperature, while decrease with pressure. Nevertheless, the diffusion coefficients in supercritical water are much larger than those in normal water.展开更多
A lead zirconate titanate(PZT)-Si energy harvester cantilever with PZT bulk ceramics is fabricated by eutectic bonding,polishing and dicing processes.The feasibility of this process is studied using a successful opera...A lead zirconate titanate(PZT)-Si energy harvester cantilever with PZT bulk ceramics is fabricated by eutectic bonding,polishing and dicing processes.The feasibility of this process is studied using a successful operation of the cantilever in both actuation and harvesting modes.The first prototype made from a PZT-Au-Si cantiliever is tested.The testing results show the voltage output of 632 mV at the frequency of 815 Hz when the excitation acceleration is 0.5 g.The PZT and silicon layers are bonded together to form a sandwiched structure using a gold layer as an intermediate layer.展开更多
基金Supported by the Shanghai Pujiang Talent Plan Sponsorship(No 09PJ1406200)the International Cooperation Project from the Ministry of Science and Technology of China(2009DFB10330)+1 种基金Aviation Key Laboratory Foundation of China(No 20080857002)and National Natural Science Foundation of China under Grant Nos 60777016,50775149 and 60976081.
文摘Polymer materials such as transparent thermoplastic poly(methyl methacrylate)(PMMA)have been of great interest in the research and development of integrated circuits and micro-electromechanical systems due to their relatively low cost and easy process.We fabricated PMMA-based polymer hollow microneedle arrays by maskdragging and aligning x-ray lithography.Techniques for 3D micromachining by direct lithography using x-rays are developed.These techniques are based on using image projection in which the x-ray is used to illuminate an appropriate gold pattern on a polyimide film mask.The mask is imaged onto the PMMA sample.A pattern with an area of up to 100×100 mm^(2)can be fabricated with sub-micron resolution and a highly accurate order of a few microns by using a dragging mask.The fabrication technology has several advantages,such as forming complex 3D micro structures,high throughput and low cost.
基金Supported by the National Natural Science Foundation of China under Grant No.29736170the Fundamental Research Foundation of Tsinghua University(No.JC1999038)and the Graduate School of Tsinghua University.
文摘Molecular dynamics simulation has been performed to determine the infinite-dilution diffusion coefficients of oxygen and nitrogen, and the diffusion coefficients of NaCl in supercritical water from 703.2-763.2 K and 30-45 MPa. The results obtained show that the diffusion coefficients in supercritical water increase with temperature, while decrease with pressure. Nevertheless, the diffusion coefficients in supercritical water are much larger than those in normal water.
基金by the International Cooperation Project from Ministry of Science and Technology of China(2009DFB10330)the Shanghai Pujiang Talent Plan(No 09PJ1406200)the National Natural Science Foundation of China under Grant No 51035005.
文摘A lead zirconate titanate(PZT)-Si energy harvester cantilever with PZT bulk ceramics is fabricated by eutectic bonding,polishing and dicing processes.The feasibility of this process is studied using a successful operation of the cantilever in both actuation and harvesting modes.The first prototype made from a PZT-Au-Si cantiliever is tested.The testing results show the voltage output of 632 mV at the frequency of 815 Hz when the excitation acceleration is 0.5 g.The PZT and silicon layers are bonded together to form a sandwiched structure using a gold layer as an intermediate layer.
