Wide-range length metrology by dual-imaging-unit atomic force microscope based on porous alumina

2004 ◽  
Vol 64 (3) ◽  
pp. 223-227 ◽  
Author(s):  
Dongxian Zhang ◽  
Haijun Zhang ◽  
Xiaofeng Lin
2021 ◽  
pp. 1-23
Author(s):  
Rafiul Shihab ◽  
Tasmirul Jalil ◽  
Burak Gulsacan ◽  
Matteo Aureli ◽  
Ryan Tung

Abstract Numerous nanometrology techniques concerned with probing a wide range of frequency dependent properties would benefit from a cantilevered sensor with tunable natural frequencies. In this work, we propose a method to arbitrarily tune the stiffness and natural frequencies of a microplate sensor for atomic force microscope applications, thereby allowing resonance amplification at a broad range of frequencies. This method is predicated on the principle of curvature-based stiffening. A macroscale experiment is conducted to verify the feasibility of the method. Next, a microscale finite element analysis is conducted on a proof-of-concept device. We show that both the stiffness and various natural frequencies of the device can be highly controlled through applied transverse curvature. Dynamic phenomena encountered in the method, such as eigenvalue curve veering, are discussed and methods are presented to accommodate these phenomena. We believe that this study will facilitate the development of future curvature-based microscale sensors for atomic force microscopy applications.


2021 ◽  
Vol 17 ◽  
Author(s):  
Ke Xu ◽  
Qiang An ◽  
Peng Li

: The atomic force microscope (AFM) is widely used in many fields such as biology, materials, and physics due to its advantages of simple sample preparation, high-resolution topography measurement and wide range of applications. However, the low scanning speed of traditional AFM limits its dynamics process monitoring and other further application. Therefore, the improvement of AFM scanning speed has become more and more important. In this review, the working principle of AFM is first proposed. Then, we introduce the improvements of cantilever, drive mechanism, and control method of the high-speed atomic force microscope (HS-AFM). Finally, we provide the next developments of HS-AFM.


2007 ◽  
Vol 35 (6) ◽  
pp. 1564-1568 ◽  
Author(s):  
D.J. Brockwell

The mechanical strength of single protein molecules can be investigated by using the atomic force microscope. By applying this technique to a wide range of proteins, it appears that the type of secondary structure and its orientation relative to the extension points are important determinants of mechanical strength. Unlike chemical denaturants, force acts locally and the mechanical strength of a protein may thus appear to be mechanically weak or strong by simply varying the region of the landscape through which the protein is unfolded. Similarly, the effect of ligand binding on the mechanical resistance of a protein may also depend on the relative locations of the binding site and force application. Mechanical deformation may thus facilitate the degradation or remodelling of thermodynamically stable proteins and their complexes in vivo.


Author(s):  
José Manoel Balthazar ◽  
Angelo Marcelo Tusset ◽  
Silvio Luiz Thomaz de Souza ◽  
Atila Madureira Bueno

The tapping mode is one of the mostly employed techniques in atomic force microscopy due to its accurate imaging quality for a wide variety of surfaces. However, chaotic microcantilever motion impairs the obtention of accurate images from the sample surfaces. In order to investigate the problem the tapping mode atomic force microscope is modeled and chaotic motion is identified for a wide range of the parameter's values. Additionally, attempting to prevent the chaotic motion, two control techniques are implemented: the optimal linear feedback control and the time-delayed feedback control. The simulation results show the feasibility of the techniques for chaos control in the atomic force microscopy.


Author(s):  
Kathleen M. Marr ◽  
Mary K. Lyon

Photosystem II (PSII) is different from all other reaction centers in that it splits water to evolve oxygen and hydrogen ions. This unique ability to evolve oxygen is partly due to three oxygen evolving polypeptides (OEPs) associated with the PSII complex. Freeze etching on grana derived insideout membranes revealed that the OEPs contribute to the observed tetrameric nature of the PSIl particle; when the OEPs are removed, a distinct dimer emerges. Thus, the surface of the PSII complex changes dramatically upon removal of these polypeptides. The atomic force microscope (AFM) is ideal for examining surface topography. The instrument provides a topographical view of individual PSII complexes, giving relatively high resolution three-dimensional information without image averaging techniques. In addition, the use of a fluid cell allows a biologically active sample to be maintained under fully hydrated and physiologically buffered conditions. The OEPs associated with PSII may be sequentially removed, thereby changing the surface of the complex by one polypeptide at a time.


Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.


Author(s):  
Jean-Paul Revel

The last few years have been marked by a series of remarkable developments in microscopy. Perhaps the most amazing of these is the growth of microscopies which use devices where the place of the lens has been taken by probes, which record information about the sample and display it in a spatial from the point of view of the context. From the point of view of the biologist one of the most promising of these microscopies without lenses is the scanned force microscope, aka atomic force microscope.This instrument was invented by Binnig, Quate and Gerber and is a close relative of the scanning tunneling microscope. Today's AFMs consist of a cantilever which bears a sharp point at its end. Often this is a silicon nitride pyramid, but there are many variations, the object of which is to make the tip sharper. A laser beam is directed at the back of the cantilever and is reflected into a split, or quadrant photodiode.


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