Fundamental Measurements of the Friction on an Atomically-Flat Terrace of Au(100) in Sulfuric Acid Solution under Potential Control Using Electrochemical Atomic Force Microscope

2006 ◽  
Vol 512 ◽  
pp. 395-398
Author(s):  
Nobumitsu Hirai ◽  
Tatsuya Tooyama ◽  
Toshihiro Tanaka
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Silicon Nitride ◽  
Acid Solution ◽  
Atomic Force Microscope ◽  
Friction Force ◽  
Potential Range ◽  
Potential Control ◽  
Atomic Force ◽  
Atomically Flat

Potential dependence of the friction force between an atomically-flat terrace of Au(100) single crystal and a tip attached to a silicon nitride cantilever of electrochemical atomic force microscope (EC-AFM) have been investigated qualitatively in 0.05 M H2SO4 aqueous solution. It is found that the friction force gains when the potential increases in the potential range between −400 mV and 400 mV vs Hg/Hg2SO4 electrode.

The atomic-force microscope and its future in biology

1993 ◽  
Vol 51 ◽  
pp. 704-705
Author(s):  
Jean-Paul Revel
Keyword(s):  
Silicon Nitride ◽  
Laser Beam ◽  
Atomic Force Microscope ◽  
Scanning Tunneling Microscope ◽  
Point Of View ◽  
Scanning Tunneling ◽  
Close Relative ◽  
Tunneling Microscope ◽  
Atomic Force ◽  
Sharp Point

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.

Rate of lactamization of benzylstrychnine in acid solution

1984 ◽  
Vol 62 (1) ◽  
pp. 144-146 ◽  
Author(s):  
John T. Edward ◽  
Sin Cheong Wong ◽  
Robert A. McClelland
Keyword(s):  
Aqueous Solution ◽  
Sulfuric Acid ◽  
Acid Solution ◽  
Acid Concentration ◽  
Amino Group ◽  
Cage Structure ◽  
Basic Formula

The rate of lactamization of benzylstrychnine in aqueous solution at 25 °C increases with acid concentration up to 5–10% sulfuric acid, and thereafter decreases. The maximum can be explained by taking account of the extent of protonation of the aromatic amino group with increasing acid concentration. This amino group is unusually weakly basic [Formula: see text], perhaps because it is locked in an extremely rigid cage structure which opposes the rehybridization of N which must take place when it is protonated.

scholarly journals Contributions of lunate cells and wax crystals to the surface anisotropy of Nepenthes slippery zone

2018 ◽  
Vol 5 (9) ◽  
pp. 180766 ◽  
Author(s):  
Lixin Wang ◽  
Dashuai Tao ◽  
Shiyun Dong ◽  
Shanshan Li ◽  
Yu Tian
Keyword(s):  
Atomic Force Microscope ◽  
Surface Topography ◽  
Friction Force ◽  
Body Length ◽  
Structural Features ◽  
Large Displacements ◽  
Surface Anisotropy ◽  
Atomic Force ◽  
Microstructure Examination ◽  
Wax Crystals

Nepenthes slippery zone presents surface anisotropy depending on its specialized structures. Herein, via macro–micro–nano scaled experiments, we analysed the contributions of lunate cells and wax crystals to this anisotropy. Macroscopic climbing of insects showed large displacements (triple body length within 3 s) and high velocities (6.16–20.47 mm s −1 ) in the inverted-fixed (towards digestive zone) slippery zone, but failed to climb forward in the normal-fixed (towards peristome) one. Friction force of insect claws sliding across inverted-fixed lunate cells was about 2.4 times of that sliding across the normal-fixed ones, whereas showed unobvious differences (1.06–1.11 times) between the inverted- and normal-fixed wax crystals. Innovative results from atomic force microscope scanning and microstructure examination demonstrated the upper layer of wax crystals causes the cantilever tip to generate rather small differences in friction data (1.92–2.72%), and the beneath layer provides slightly higher differences (4.96–7.91%). The study confirms the anisotropic configuration of lunate cells produces most of the anisotropy, whereas both surface topography and structural features of the wax crystals generate a slight contribution. These results are helpful for understanding the surface anisotropy of Nepenthes slippery zone, and guide the design of bioinspired surface with anisotropic properties.

Surface-Enhanced Raman Scattering and Atomic Force Microscopy of Brass Electrodes in Sulfuric Acid Solution Containing Benzotriazole and Chloride Ion

1993 ◽  
Vol 47 (1) ◽  
pp. 80-84 ◽  
Author(s):  
Joel C. Rubim ◽  
Jae-Ho Kim ◽  
Eric Henderson ◽  
Therese M. Cotton
Keyword(s):  
Atomic Force Microscopy ◽  
Sulfuric Acid ◽  
Raman Scattering ◽  
Acid Solution ◽  
Chloride Ion ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering

Three different methods were used to roughen brass (Cu/Zn = 67/33) electrodes in 0.5 M H2SO4 containing 1.0 mM benzotriazole (BTAH): (1) polarization at +0.05 V vs. saturated calomel for 5 min; (2) immersion in the above solution for six hours; and (3) oxidation-reduction cycling in the presence of chloride ion. The surfaces prepared by the first two methods exhibited surface-enhanced Raman scattering (SERS) spectra of the polymeric complex [Cu(I)BTA] n. The SERS spectrum obtained from electrodes prepared by the third method is very similar to that of [CU(I)C1BTAH]4. Examination of the electrodes by atomic force microscopy (AFM) showed that a large number of grain boundary sites are formed by the roughening processes. This effect is attributed to the loss of zinc, which occurs during corrosion of the mirror-like, polished brass electrode surface in the sulfuric acid solution.

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