SPS Lunch Lectures
SPS Lunch Lectures will be held in Hewlett 102 on Wednesdays from noon
to 1pm. Talks will be aimed at undergraduates in a colloquium environment.
These are highly recommended to attend for those interested in undergraduate
research as well as anyone interested in physics at Stanford.
Spring Quarter Lectures
- 5/5/2006: Dan Green (Institute for Theoretical Physics), Everything
you know about the Tacoma Narrows Bridge is Wrong
The cause of the collapse of the Tacoma Narrows Bridge
has been a topic of much debate and confusion since the day it fell.
Many mischaracterizations of the observed phenomena have limited the
widespread understanding of the problem. Nevertheless, there has always
been an abundance of evidence in favour of a negative damping model.
Negative damping, or positive feedback, is responsible for many large
amplitude oscillations observed in many applications. In this paper,
we will explain some well-known examples of positive feedback. We will
then present a feedback model, derived from fundamental physics, capable
of explaining a number of features observed in the instabilities of
many bridge decks. This model is supported by computational, experimental
and historical data.
- 5/12/2006: Mustafa Amin (Kavli Institute for Particle Astrophysics and
Cosmology), Persistent spiral patterns aroudn rotating black holes
- 5/26/2006: Navin Sivanandam (Institute for Theoretical Physics and Stanford
Daily), TBA
Winter Quarter Lectures
- 1/18/2006: Felicia
Tam (Rice Quantum Institute), Gold Nanoparticle Plasmon Enhanced
Fluorescence of Indocyanine Green
Recent studies have reported that metal nanoparticles
can enhance the emission of fluorescent molecules in the vicinity of
the nanoparticle. The results of fluorescence enhancement studies on
both metal nanoparticles and films are typically explained using surface
plasmons, the collective oscillation of valence electrons in the metal.
To elucidate the role that the local surface plasmon resonance (LSPR)
plays in modification of the fluorophore emission, we investigate the
fluorescence emission from indocyanine green (ICG) in the vicinity of
nanoshells. Nanoshells are dielectric-core metal-shell particles which
have tunable plasmon resonances that span the visible and IR portions
of the electromagnetic spectrum. Because a gold shell-silica core nanoshell
can be fabricated to have plasmon resonance energies that overlap the
absorption and emission bands of ICG, the nanoparticle can alter how
the fluorophore absorbs and emits light. In addition, the concentric
spherical geometry of nanoshells allows us to use Mie Scattering Theory
to quantitatively understand how the nanoshells alter the local photonic
density of states for the fluorophore. We report the affects of nanoparticle
plasmons on ICG fluorescence emission by systematically altering the
size of the nanoshell core and shell to change the absorption and scattering
properties of the plasmon which interacts with surrounding ICG fluorophores.
- 2/1/2006: Michael
Peskin (SLAC), To Be Announced
- 2/15/2006: Simon Klemperer
(Geophysics), To Be Announced
- 3/1/2006: Sidney
Drell (SLAC), To Be Announced, date tentative
Fall Quarter Lectures
- 10/12/2005: Adam
Cohen, Trapping and Manipulating Individual Molecules in Solution
- 11/02/2005: Professor
Richard Zare (Chemistry), How To Succeed in Research
- 11/09/2005: Professor
Roger Romani, Punting, English and Neutron Stars
I'll discuss how new measurements of pulsar motion and spin can
constrain their birth supernova events and, possibly, the physics
of neutrinos.
- 11/30/2005: Professor
Stephen Quake (Bioengineering), Biological Large Scale Integration:
The integrated circuit revolution changed our lives
by automating computational tasks on a grand scale. My group has been
asking whether a similar revolution could be enabled by automating biological
tasks. To that end, we have developed a method of fabricating very small
plumbing devices – chips with small channels and valves that manipulate
fluids containing biological molecules and cells, instead of the more
familiar chips with wires and transistors that manipulate electrons.
Using this technology, we have fabricated chips that have thousands
of valves in an area of one square inch. We are using these chips in
applications ranging from screening to structural genomics to ultrasensitive
genetic analysis. However, there is also a substantial amount of basic
physics to explore with these systems – the properties of fluids
change dramatically as the working volume is scaled from milliliters
to nanoliters!
Upcoming Events
- f10/31/2005: 13th Annual Physics Halloween "BOO-B-Q"
in Stone Plaza (behind Varian Physics building). Door prizes and pumpkin
carving to go along
Stanford Colloquia and Seminars
In addition to our SPS Lunch Lectures, there are several physics-related
colloquia and seminars on campus. Many of these are aimed at a graduate
audience but are still an excellent source of information for undergraduates--even,
as the conventional wisdom goes, if one does not understand the entire talk.
Please e-mail Flip (
) if we've missed something!
Past Photos
If you haveimages to share, please e-mail the webmaster ().
"Varian II" building under construction, Varian Webcam
circa. September 2005.
