Browsing by Subject "Measurements of"

Now showing 1 - 3 of 3

Open Access
Artifacts related to tip asymmetry in high-resolution atomic force microscopy and scanning tunneling microscopy measurements of graphitic surfaces
(American Institute of Physics Inc., 2015) Uluutku, B.; Baykara, M. Z.
The effect of tip asymmetry on atomic-resolution scanning tunneling microscopy and atomic force microscopy measurements of graphitic surfaces has been investigated via numerical simulations. Employing a three-dimensional, crystalline, metallic tip apex and a two-layer thick graphene sample as a model system, basic calculations of the tip-sample interaction have revealed a significant effect of tip asymmetry on obtained results, including artificial modulation of site-specific chemical interaction forces and spatial distortion of observed features. Related artifacts are shown to be enhanced for tips with low lateral stiffness values. Our results emphasize that potentially erroneous interpretations of atomic-scale surface properties via imaging and spectroscopy measurements can be caused or enhanced by tip asymmetry.
Open Access
Experimental conditions for the excitation of thin disk whispering-gallery-mode resonators
(Electromagnetics Academy, 2013) Yurchenko, V. B.; Altintas, A.; Ciydem, M.; Koc, S.
Measurements of mm-wave excitation spectra of highorder whispering gallery modes in free-space cylindrical disk resonators as functions of resonator thickness have been made. Resonators in the form of tight stacks of thin dielectric disks excited via dielectric waveguides have been used in the experiment. Experimental conditions for the excitation of thin-disk resonators have been found. A simple approach for the modeling of resonator spectra and recovery of dielectric parameters has been proposed.
Open Access
Liquid bulk rotation induced by electric field at free surface
(American Institute of Physics Inc., 2015) Saghaei, T.; Moradi, A.-R.; Shirsavar, R.; Habibi, M.
In this paper, we induce rotation in a bulk of polar liquid with one free surface, by applying external crossed electric fields. We show that the induced rotation is due to the imposed stresses at the free surface of the liquid. A simple theoretical model was developed based on solving the Navier-Stokes equation that enables us to calculate the average induced stress in the liquid bulk, using experimental measurements of the angular velocity of the liquid. Our results indicate that the induced stresses and the angular velocities of the rotating liquid are independent from the electrical conductivity of the liquid. However, the induced stresses linearly depend on the external electric field and the applied electric voltage for passing the electric current through the bulk. Both experimental results and the theoretical model show that the angular velocity, linearly changes with depth. © 2015 AIP Publishing LLC.