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Physics research: Interesting questions, Interesting Independent Lab projects

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Physics research: Interesting questions, Interesting Independent Lab projects Daniel W. Koon Spring 2005 – PowerPoint PPT presentation

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Title: Physics research: Interesting questions, Interesting Independent Lab projects


1
Physics researchInteresting questions,
Interesting Independent Lab projects
  • Daniel W. Koon
  • Spring 2005

2
Goals of this talk
  • Describe some general subtopics of physics
  • Solid State physics
  • Optics
  • Describe some interesting research questions,
    including my own research
  • Suggest some Independent Lab project ideas

3
Structure of this talk
  • Solid state physics
  • Research areas
  • project ideas
  • Optics
  • Research areas
  • project ideas
  • Miscellaneous project ideas

4
Solid state physics charge transport
  • Charge transport
  • the measurement of resistivity and Hall effect
  • a cheap sub-atomic microscope
  • A cheap sub-atomic microscope How so?
  • Its cheap
  • It explores how the molecules of the material
    treat their electrons

5
Resistivity, r
  • Resistance, R measures how an object resists the
    flow of current
  • Resistivity, r measures how a material resists
    the flow of current
  • So, (SAT flashback)
  • r R Density mass
  • G(size,shape) R

6
The Hall coefficient the other charge transport
quantity
  • The Lorentz force
  • Gives rise to a Hall voltage
  • (The Hall effect is the bending of current due to
    a magnetic field.)

7
Punchline charge transport as a cheap subatomic
microscope
  • Since
  • we can deduce the microscopic quantities by

8
Koons solid state interests
  • I. The phenomenology of charge transport
    measurement
  • Error analysis What do you measure when you
    measure r, RH?
  • Is there a best sample shape?

9
Error analysis How to do it
  • Using computer to model current flow in the
    specimen
  • To compare different geometries
  • To test effects of thickness
  • Using a discrete-resistor model in the laboratory
  • To test linearity of the effect

10
Koons solid state interests
  • II. Applying charge transport measurement to
    specific materials
  • Hydrogen absorption in rare-earth/Pd bilayers
  • Challenges
  • Rare earths corrode in O2.
  • Pd overlayer stops corrosion, allows H2
    absorption.
  • Pd is a much better conductor.
  • So, how do you measure the properties of just the
    RE?

11
Interesting Solid State questions
  • Is the effect of resistive inhomogeneities
    linear? Is it additive (If I poke twice as big a
    hole in a film does it produce twice the effect?)
  • Can we simultaneously measure the resistivity and
    transmittance of a hydriding or corroding film?
  • How does the resistivity, Hall coefficient of a
    material change as it freezes/thaws?

12
Optics Biomaterials and more
  • Photonic Polar bears?
  • Solar efficient butterflies?
  • Ulexite (TV rock)
  • Scarlet macaws

13
  • The hairs of the polar bear are transparent light
    pipes that direct ultraviolet light to its skin
    -- which is guess what color? Black! So whats
    white and black and warm all over? A polar bear
    under the arctic sun.
  • Paul G. Hewitt, Conceptual Physics, 6th Edition,
    1989, p. 501

14
  • Aristotle maintained that women have fewer
    teeth than men although he was twice married, it
    never occurred to him to verify this statement by
    examining his wives mouths.
  • Bertrand Russell

15
Optical attenuation spectrumpolar bear hair
16
FOUL(UP)A Fiber-Optic Ursine Link (Universal
Prototype)for telecommunicationsD. W. Koon and
C. L. Jahncke, Physics Dept., St. Lawrence
University
  • ABSTRACT We have constructed what we believe
    is the first prototype of a fiber-optic link to
    use the hair of an Arctic mammal. The potential
    advantages of ursine fiber technology over
    conventional technology are discussed.
  • http// it.stlawu.edu/physics/clj/foulup.html

17
Interesting Optics questions
  • Polar bear hairs as optical fibers?
  • Reid Hutchins 98
  • Morpho butterflies Does iridescence serve as a
    solar panel or a sunblock?
  • Andy Crawford 99
  • Ulexite (TV rock) Is there cross talk in the
    fiber optic bundles?
  • Jay OBrien 98
  • The scarlet macaw Thin-film iridescence, or
    diffraction grating, or what?

18
Miscellaneous interesting questions
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