The AFM image will be distorted due to the tip-broadening effect. It may be mathematically represented as the effect of the tip's convolution on the real image. As a result, the true geometry of the sample surface...The AFM image will be distorted due to the tip-broadening effect. It may be mathematically represented as the effect of the tip's convolution on the real image. As a result, the true geometry of the sample surface can not be obtained. If the tip shape could be known accurately, such distortion can be eliminated with the adoption of disconvolution operation. It is of practical significance in the accurate reconstruction of the AFM image. Among the current tip modeling algorithms, the blind tip estimation algorithm based on mathematical morphology is widely applied. However, it takes much time and has difficulties in defining the optimal noise threshold. In view of the above problems, this paper proposes a new blind tip evaluation method to accelerate the speed of blind tip modeling calculation and realize the accurate reconstruction of the AFM image. The simulation and the experimental results demonstrate the feasibility and effectiveness of the above research method.展开更多
The invention of atomic force microscopy(AFM) has provided new technology for measuring specific molecular interaction forces.Using AFM single-molecule force spectroscopy(SMFS) techniques,CD20-Rimximab rupture forces ...The invention of atomic force microscopy(AFM) has provided new technology for measuring specific molecular interaction forces.Using AFM single-molecule force spectroscopy(SMFS) techniques,CD20-Rimximab rupture forces were measured on purified CD20 proteins,Raji cells,and lymphoma patient B cells.Rimximab molecules were linked onto AFM tips using AFM probe functionalization technology,and purified CD20 proteins were attached to mica using substrate functionalization technology.Raji cells(a lymphoma cell line) or lymphoma patient cells were immobilized on a glass substrate via electrostatic adsorption and chemical fixation.The topography of the purified CD20 proteins,Raji cells,and patient lymphoma cells was visualized using AFM imaging and the differences in the rupture forces were analyzed and measured.The results showed that the rupture forces between the CD20 proteins on Raji cells and Rituximab were markedly smaller than those for purified CD20 proteins and CD20 proteins on lymphoma patient B cells.These findings provide an effective experimental method for investigating the mechanisms underlying the variable efficacy of Rituximab.展开更多
In this work, a development of a method of a thin insulating film vertical edge visualization of metal-insulator-metal （MIM） memory cells with atomic force microscopy （AFM） using a modified Omicron UHV AFM/STM mic...In this work, a development of a method of a thin insulating film vertical edge visualization of metal-insulator-metal （MIM） memory cells with atomic force microscopy （AFM） using a modified Omicron UHV AFM/STM microscope was performed. This included a development of a technique of the AFM visualization of segments of a vertical edge of thin insulator SiO2 film structures on a conductive substrate, a comparison of AFM topography and current profilograms for the edge profiles, and an Omicron microscope custom upgrade. The latter allowed us to perform the AFM probe positioning to any specific area of the sample in the scanning plane by two coordinates with an order of precision of 1 micrometer. The method is illustrated with the experimental results of AFM investigations of the special MIM structures with comb-type topology, and of the cells of functioning memory matrices with 20 nm thin silicon dioxide film open edge perimeter and TiN lower electrode, including topography/current profilograms. As a conclusion, our ongoing work on the AFM visualization of a complete perimeter of a SiO2 open edge of memory cells with a special new topology with a goal to visualize conductive phase nanoparticles during switching processes is briefly overviewed.展开更多
基金supported by the National Natural Science Foundation of China (60635040)National High-Tech Research and Development Program of China (2009AA04Z313, 2009AA03Z316)Research supported by the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘The AFM image will be distorted due to the tip-broadening effect. It may be mathematically represented as the effect of the tip's convolution on the real image. As a result, the true geometry of the sample surface can not be obtained. If the tip shape could be known accurately, such distortion can be eliminated with the adoption of disconvolution operation. It is of practical significance in the accurate reconstruction of the AFM image. Among the current tip modeling algorithms, the blind tip estimation algorithm based on mathematical morphology is widely applied. However, it takes much time and has difficulties in defining the optimal noise threshold. In view of the above problems, this paper proposes a new blind tip evaluation method to accelerate the speed of blind tip modeling calculation and realize the accurate reconstruction of the AFM image. The simulation and the experimental results demonstrate the feasibility and effectiveness of the above research method.
基金supported by the National Natural Science Foundation of China (60904095)National High Technology Research and Development Program of China (2009AAO3Z316)CAS FEA International Partnership Program for Creative Research Teams
文摘The invention of atomic force microscopy(AFM) has provided new technology for measuring specific molecular interaction forces.Using AFM single-molecule force spectroscopy(SMFS) techniques,CD20-Rimximab rupture forces were measured on purified CD20 proteins,Raji cells,and lymphoma patient B cells.Rimximab molecules were linked onto AFM tips using AFM probe functionalization technology,and purified CD20 proteins were attached to mica using substrate functionalization technology.Raji cells(a lymphoma cell line) or lymphoma patient cells were immobilized on a glass substrate via electrostatic adsorption and chemical fixation.The topography of the purified CD20 proteins,Raji cells,and patient lymphoma cells was visualized using AFM imaging and the differences in the rupture forces were analyzed and measured.The results showed that the rupture forces between the CD20 proteins on Raji cells and Rituximab were markedly smaller than those for purified CD20 proteins and CD20 proteins on lymphoma patient B cells.These findings provide an effective experimental method for investigating the mechanisms underlying the variable efficacy of Rituximab.
文摘In this work, a development of a method of a thin insulating film vertical edge visualization of metal-insulator-metal （MIM） memory cells with atomic force microscopy （AFM） using a modified Omicron UHV AFM/STM microscope was performed. This included a development of a technique of the AFM visualization of segments of a vertical edge of thin insulator SiO2 film structures on a conductive substrate, a comparison of AFM topography and current profilograms for the edge profiles, and an Omicron microscope custom upgrade. The latter allowed us to perform the AFM probe positioning to any specific area of the sample in the scanning plane by two coordinates with an order of precision of 1 micrometer. The method is illustrated with the experimental results of AFM investigations of the special MIM structures with comb-type topology, and of the cells of functioning memory matrices with 20 nm thin silicon dioxide film open edge perimeter and TiN lower electrode, including topography/current profilograms. As a conclusion, our ongoing work on the AFM visualization of a complete perimeter of a SiO2 open edge of memory cells with a special new topology with a goal to visualize conductive phase nanoparticles during switching processes is briefly overviewed.
