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Full-Text Articles in Physics

Viscosity Dependent Liquid Slip At Molecularly Smooth Hydrophobic Surfaces, Sean P. Mcbride, Bruce M. Law Dec 2009

Viscosity Dependent Liquid Slip At Molecularly Smooth Hydrophobic Surfaces, Sean P. Mcbride, Bruce M. Law

Physics Faculty Research

Colloidal probe atomic force microscopy is used to study the slip behavior of 18 Newtonian liquids from two homologous series, the n-alkanes and n-alcohols, at molecularly smooth hydrophobic n-hexadecyltrichlorosilane coated surfaces. We find that the slip behavior is governed by the bulk viscosity η of the liquid, specifically, the slip length b∼ηx with x∼0.33. Additionally, the slip length was found to be shear rate independent, validating the use of Vinogradova slip theory in this work.


Nanoscopic Investigation Of Surface Morphology Of Neural Growth Cones And Indium Containing Group-Iii Nitrides, Göksel Durkaya Dec 2009

Nanoscopic Investigation Of Surface Morphology Of Neural Growth Cones And Indium Containing Group-Iii Nitrides, Göksel Durkaya

Physics and Astronomy Dissertations

This research focuses on the nanoscopic investigation of the three-dimensional surface morphology of the neural growth cones from the snail Helisoma trivolvis, and InN and InGaN semiconductor material systems using Atomic Force Microscopy (AFM). In the analysis of the growth cones, the results obtained from AFM experiments have been used to construct a 3D architecture model for filopodia. The filopodia from B5 and B19 neurons have exhibited different tapering mechanisms. The volumetric analysis has been used to estimate free Ca2+ concentration in the filopodium. The Phase Contrast Microscopy (PCM) images of the growth cones have been corrected to thickness provided …


Strain Energy And Lateral Friction Force Distributions Of Carbon Nanotubes Manipulated Into Shapes By Atomic Force Microscopy, Mark C. Strus, Roya R. Lahiji, Pablo Ares, Vincente Lopez, Arvind Raman, Ron R. Reifenberger Aug 2009

Strain Energy And Lateral Friction Force Distributions Of Carbon Nanotubes Manipulated Into Shapes By Atomic Force Microscopy, Mark C. Strus, Roya R. Lahiji, Pablo Ares, Vincente Lopez, Arvind Raman, Ron R. Reifenberger

Other Nanotechnology Publications

The interplay between local mechanical strain energy and lateral frictional forces determines the shape of carbon nanotubes on substrates. In turn, because of its nanometer-size diameter, the shape of a carbon nanotube strongly influences its local electronic, chemical, and mechanical properties. Few, if any, methods exist for resolving the strain energy and static frictional forces along the length of a deformed nanotube supported on a substrate. We present a method using nonlinear elastic rod theory in which we compute the flexural strain energy and static frictional forces along the length of single walled carbon nanotubes (SWCNTs) manipulated into various shapes …


Transport Property Measurements Of Bi_2se_3 Crystal Grown By Bridgman Method, M. P. Deshpande, Nilesh N. Pandya, M. N. Parmar Jan 2009

Transport Property Measurements Of Bi_2se_3 Crystal Grown By Bridgman Method, M. P. Deshpande, Nilesh N. Pandya, M. N. Parmar

Turkish Journal of Physics

This paper deals with the growth of Bi_2Se_3 crystal by newly designed experimental set-up of Bridgman technique in our laboratory. Grown crystal is characterized by EDAX (Energy Dispersive Analysis of X-rays), XRD (X-ray Diffraction), low temperature thermopower measurements (17-284 K), resistivity measurements (16-294 K) and Hall Effect at room temperature in order to study its various properties. The surface study of the grown crystal using AFM (Atomic Force Microscopy) shows a hexagonal unit cell shape whose internal angle determined comes out to be nearly equal to 122.94° which has close resemblance with an angle of 120° of perfect internal angle …


Nano-Structure Formation Driven By Local Protonation Of Polymer Thin Films, Carsten Maedler, Harald Graaf, Mingdi Yan, Andres H. La Rosa Jan 2009

Nano-Structure Formation Driven By Local Protonation Of Polymer Thin Films, Carsten Maedler, Harald Graaf, Mingdi Yan, Andres H. La Rosa

Physics Faculty Publications and Presentations

We report the creation of nano-structures via Dip Pen Nanolithography by locally exploiting the mechanical response of polymer thin films to an acidic environment. Protonation of cross linked poly(4-vinylpyridine) (P4VP) leads to a swelling of the polymer. We studied this process by using an AFM tip coated with a pH 4 buffer. Protons migrate through a water meniscus between tip and sample into the polymer matrix and interact with the nitrogen of the pyridyl group forming a pyridinium cation. The increase in film thickness, which is due to Coulomb repulsion between the charged centers, was investigated using Atomic Force Microscopy. …