Evan Pease represented the physics department at the Hope College Summer Undergraduate Research Function dinner at the Haworth Inn and Conference Center yesterday. One student from each department gave a 5 minute summary of their work. Evan presented the fresh results from the Microwave Lab shown on this blog on July 7. Here is Evan’s presentation.
On Tuesday, Physics & Engineering research students joined with Computer Science research students to attend the first of two seminars on ethical conduct in research. These seminars are being led by Dr. Mark Pearson, Associate Professor of Mathematics, and focus on case studies, both real and fictitious.
A SCIENTIFIC FIRST!!!
Evan Pease is measuring the even and odd order distortion signals from a superconducting microwave filter. He is using three input signals with a method being developed exclusively in the Hope College Microwave Lab called 3-tone intermodulation
distortion. This ground breaking research will help to establish the limits of superconductivity in microwave electronics and at the same time reveal new insights into the physics of high temperature superconducting materials. The graph to the right (click on it) shows the 3rd order nonlinearity, revealing a “nonlinearity catastrophe” at the superconducting transition temperature. Evan is measuring signals as small as 30 femtoWatts in this experiment.
Nick Wozniak and Alyssa Frey both took turns at the controls of the AFM.
The purpose of the trip was to look at the surface structure of several electrodeposited thin films. We looked at both nickel-iron alloy samples and copper samples.
In order to swap the samples, first, the AFM head must be removed. This is the most delicate part of the instrument, containing the AFM cantilever (or “tip”), the laser, and the photodetector. Here Jenny Hampton disconnects the electronic connection between the head and the scanner before removing the head.
After the AFM head is replaced, the tip can be positioned on the sample to image a particular area. Here Alyssa moves the tip from one location to another with the help of the live image feed from the optical microscope.
The AFM in Kumar Sinnah’s lab is optimized for measuring small forces. Dr. Sinnah uses the AFM to investigate interactions (such as binding or recognition) between biological molecules. However, atomic force microscopy was originally developed to image the nano- and micro-scale structure of surfaces, which is what we measured.
The trip was a success. Before we headed back to Holland in the late afternoon, we took a moment to try the ergonomically designed chairs in the lobby of the Science Complex.