The design and fabrication processes of a novel scanner with minimized coupling motions for a high-speed atomic force microscope （AFM） were addressed. An appropriate design modification was proposed through the anal...The design and fabrication processes of a novel scanner with minimized coupling motions for a high-speed atomic force microscope （AFM） were addressed. An appropriate design modification was proposed through the analyses of the dynamic characteristics of existing linear motion stages using a dynamic analysis program, Recurdyn. Because the scanning speed of each direction may differ, the linear motion stage for a high-speed scanner was designed to have different resonance frequencies for the modes, with one dominant displacement in the desired directions. This objective was achieved by using one-direction flexure mechanisms for each direction and mounting one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separated the frequencies of two vibration modes with one dominant displacement in each desired direction, and hence suppressed the coupling between motions in two directions. A pair of actuators was used for each axis to decrease the crosstalk between the two motions and give a sufficient force to actuate the slow motion stage, which carried the fast motion stage, A lossy material, such as grease, was inserted into the flexure hinge to suppress vibration problems that occurred when using an input triangular waveforrn. With these design modifications and the vibration suppression method, a novel scanner with a scanning speed greater than 20 Hz is achieved.展开更多
The hydration film on particle surface plays an important role in bubble-particle adhesion in mineral flotation process. The thicknesses of the hydration films on natural hydrophobic coal and hydrophilic mica surfaces...The hydration film on particle surface plays an important role in bubble-particle adhesion in mineral flotation process. The thicknesses of the hydration films on natural hydrophobic coal and hydrophilic mica surfaces were measured directly by atomic force microscopy (AFM) based on the bending mode of the nominal constant compliance regime in AFM force curve in the present study. Surface and solid-liquid interfacial energies were calculated to explain the forming mechanism of the hydration film and atomic force microscopy data. The results show that there are significant differences in the structure and thickness of hydration films on coal and mica surfaces. Hydration film formed on mica surface with the thickness of 22.5 nm. In contrast, the bend was not detected in the nominal constant compliance regime. The van der Waals and polar interactions between both mica and coal and water molecules are characterized by an attractive effect, while the polar attractive free energy between water and mica (-87.36 mN/m) is significantly larger than that between water and coal (-32.89 mN/m), which leads to a thicker and firmer hydration layer on the mica surface. The interfacial interaction free energy of the coal/water/bubble is greater than that of mica. The polar attractive force is large enough to overcome the repulsive van der Waals force and the low energy barrier of film rupture, achieving coal particle bubble adhesion with a total interfacial free energy of-56.30 mN/m.展开更多
原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥...原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥青结合料与集料之间的水分相互作用是一种出现在微观尺度,甚至纳米尺度的现象,因此从微纳观角度探究在水分存在条件下沥青与集料的结构变化,对于改善沥青混合料水稳定性能,探究其水损害机制具有深远的意义。本文在总结AFM工作原理及沥青微观“bees”结构特性的基础上,重点分析了AFM在纳米尺度上对沥青混合料水稳性能的研究成果,并探讨了AFM在沥青路面材料研究中的发展方向,为今后对于沥青路面病害研究与防治方面提供一定的借鉴。展开更多
原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的...原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的技术实现方案,并研制了相应的标定系统。借助精密运动定位台使微悬臂梁接触超精密天平并产生弯曲,分别以天平和光杠杆机构同步测得接触力和梁的弯曲量,再根据胡克定律直接算得弹性常数。利用所研制的系统对多种型号的微悬臂梁进行了标定,实验结果表明该系统具有良好的准确性和重复性,测量相对标准差小于5%。展开更多
DNA/octadecylamine(ODA) monolayers were transferred onto silicon substrates and the morphologies of the monolayers were investigated by Atomic Force Microscope(AFM). AFM images show that the morphologies of DNA dissol...DNA/octadecylamine(ODA) monolayers were transferred onto silicon substrates and the morphologies of the monolayers were investigated by Atomic Force Microscope(AFM). AFM images show that the morphologies of DNA dissolved in pure water are very different from those of DNA dissolved in the NaCl solution. When DNA molecules are dissovled in pure water, they will form ball-like structure in the monolayer. When the DNA molecules are dissolved in NaCl solution, they will form bunch lines. This DNA line offers a valuable template to direct the formation of unique inorganic nanomaterials.展开更多
基金Work(R0A-2007-000-20042-0) partly supported by the Second Stage of Brain Korea 21 Projectspartly by the Korea Science and Engineering Foundation (KOSEF) through the National Research Laboratory Program funded by the Ministry of Science and Technology of Korea
文摘The design and fabrication processes of a novel scanner with minimized coupling motions for a high-speed atomic force microscope （AFM） were addressed. An appropriate design modification was proposed through the analyses of the dynamic characteristics of existing linear motion stages using a dynamic analysis program, Recurdyn. Because the scanning speed of each direction may differ, the linear motion stage for a high-speed scanner was designed to have different resonance frequencies for the modes, with one dominant displacement in the desired directions. This objective was achieved by using one-direction flexure mechanisms for each direction and mounting one stage for fast motion on the other stage for slow motion. This unsymmetrical configuration separated the frequencies of two vibration modes with one dominant displacement in each desired direction, and hence suppressed the coupling between motions in two directions. A pair of actuators was used for each axis to decrease the crosstalk between the two motions and give a sufficient force to actuate the slow motion stage, which carried the fast motion stage, A lossy material, such as grease, was inserted into the flexure hinge to suppress vibration problems that occurred when using an input triangular waveforrn. With these design modifications and the vibration suppression method, a novel scanner with a scanning speed greater than 20 Hz is achieved.
基金Project(2014BAB01B03)supported by the National Key Technology R&D Program During the 12th Five-Yean Plan of ChinaProject(51774286)supported by the National Natural Science Foundation of ChinaProject(BK20150192)supported by the Natural Science Foundation of Jiaaagsu Province,China
文摘The hydration film on particle surface plays an important role in bubble-particle adhesion in mineral flotation process. The thicknesses of the hydration films on natural hydrophobic coal and hydrophilic mica surfaces were measured directly by atomic force microscopy (AFM) based on the bending mode of the nominal constant compliance regime in AFM force curve in the present study. Surface and solid-liquid interfacial energies were calculated to explain the forming mechanism of the hydration film and atomic force microscopy data. The results show that there are significant differences in the structure and thickness of hydration films on coal and mica surfaces. Hydration film formed on mica surface with the thickness of 22.5 nm. In contrast, the bend was not detected in the nominal constant compliance regime. The van der Waals and polar interactions between both mica and coal and water molecules are characterized by an attractive effect, while the polar attractive free energy between water and mica (-87.36 mN/m) is significantly larger than that between water and coal (-32.89 mN/m), which leads to a thicker and firmer hydration layer on the mica surface. The interfacial interaction free energy of the coal/water/bubble is greater than that of mica. The polar attractive force is large enough to overcome the repulsive van der Waals force and the low energy barrier of film rupture, achieving coal particle bubble adhesion with a total interfacial free energy of-56.30 mN/m.
文摘原子力显微镜(Atomic force microscope,AFM)不仅可以从纳米尺度观测沥青表面微观结构,还可以应用不同模式测试其微观力学特性,是研究沥青路面材料微观特性的有力工具。沥青混合料的水损害已经成为沥青路面的主要病害之一,研究表明,沥青结合料与集料之间的水分相互作用是一种出现在微观尺度,甚至纳米尺度的现象,因此从微纳观角度探究在水分存在条件下沥青与集料的结构变化,对于改善沥青混合料水稳定性能,探究其水损害机制具有深远的意义。本文在总结AFM工作原理及沥青微观“bees”结构特性的基础上,重点分析了AFM在纳米尺度上对沥青混合料水稳性能的研究成果,并探讨了AFM在沥青路面材料研究中的发展方向,为今后对于沥青路面病害研究与防治方面提供一定的借鉴。
文摘原子力显微镜(atomic force microscopy,AFM)在微纳米尺度力学测量领域有着广泛应用,其微悬臂梁探针的弹性常数是直接影响测量结果准确性的关键因素之一。弯曲法是标定微悬臂梁弹性常数的一类重要方法,基于弯曲标定原理提出了一种新的技术实现方案,并研制了相应的标定系统。借助精密运动定位台使微悬臂梁接触超精密天平并产生弯曲,分别以天平和光杠杆机构同步测得接触力和梁的弯曲量,再根据胡克定律直接算得弹性常数。利用所研制的系统对多种型号的微悬臂梁进行了标定,实验结果表明该系统具有良好的准确性和重复性,测量相对标准差小于5%。
文摘DNA/octadecylamine(ODA) monolayers were transferred onto silicon substrates and the morphologies of the monolayers were investigated by Atomic Force Microscope(AFM). AFM images show that the morphologies of DNA dissolved in pure water are very different from those of DNA dissolved in the NaCl solution. When DNA molecules are dissovled in pure water, they will form ball-like structure in the monolayer. When the DNA molecules are dissolved in NaCl solution, they will form bunch lines. This DNA line offers a valuable template to direct the formation of unique inorganic nanomaterials.
