Colloquium Schedule

Colloquium: Thursday, April 16, 4:10 PM, Lewis Lab 316

From Material Substance to Shape to Property

Boris I. Yakobson

Professor of Materials Science, Nano-Engineering, and Chemistry
Rice University

Connecting the underlying chemical processes with the growth and emergent form remains unsurmountable problem in life sciences [1]. In materials research, the current outlook is more optimistic: establishing such connection, from the basic interatomic forces to growing nanostructure shape and properties becomes a real possibility. We will discuss several important examples, focusing on two recent results. First one concerns the nanotubes, where it took two decades to derive a kinetic formula [2] R ~ sin x (growth rate R, helical angle x). Further analysis of the subtle balance between the kinetic and thermodynamic views reveals sharply peaked abundance distribution A ~ x exp (-x) [3]. This explains the puzzling (n, n-1) types observed in many experiments. In the second example, a combination of DFT and Monte Carlo models explains the low symmetry shapes of graphene on substrates. In equilibrium, edge energy variation dE manifests in slightly distorted hexagons. In growth, it enters as ~exp(-dE/kT), amplifying the symmetry breaking to triangle, ribbon, rhomb [4].
[1] On Growth and Form, by D’Arcy W. Thompson (Cambridge U, 1917).
[2] F. Ding et al. PNAS 106, 2506 (2009); R. Rao et al. Nature Mater. 11, 213 (2012).
[3] V. Artyukhov - E. Penev et al. Nature Comm. 5, 489 (2014).
[4] Y. Liu et al. PRL 105, 235502 (2010); V. Artyukhov et al. PNAS 109, 15136 (2012); Y. Hao et al. Science, 342, 720 (2013); V.
Artyukhov et al. PRL, in press (2015).

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Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:10 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 3:45 PM.

 

Physics Colloquium Schedule for SPRING 2015

Click on Title below for past or upcoming Announcements (where available), and Speaker name for website.        

DateSpeakerAffiliationTitle
January 22Rosi ReedWayne State UniversityThe Connection Between Quantum Chromodynamics and the Quark Gluon Plasma
January 29Marguerite TonjesUniv. of MarylandStudying the Quark-Gluon Plasma at the Large Hadron Collider
February 5Jean PerezUniv. of New HampshireNew Horizons in Solar Wind Turbulence:
Theory, Simulations and Future Observations
February 12Sera CremoniniTexas A & M Univ."Applied" String Theory
February 19Cindy KeelerNiels Bohr InstituteString Theory in the Age of Duality
February 24 (Tuesday)Yelena ProkOld Dominion Univ.Nucleon Spin Structure: New Results from Jefferson Lab
February 26Dean LeeNorth Carolina StateAre the Parameters of the Standard Model Fine-Tuned for Carbon-Based Life?
March 5No ColloquiumAPS March Meeting-
March 12No ColloquiumSpring Break-
March 19Lev MurokhQueens College, CUNYEnergy Conversion in Mitochondria Membranes: Principles of Operations and Ideas for Nanoelectronics
March 26Nader EnghetaU PennOptics at the Extreme
April 2Anand JagotaLehigh Univ.Influence of Surface Tension Deformation of Compliant Solids
April 9Taeyoon KimPurdue Univ.Force Generation and Mechano-Sensing via Actomyosin Contractility
April 16Boris YakobsonRice UniversityFrom Material Substance to Shape to Property
April 23Dmitry SmirnovFlorida State Univ.When High Magnetic Fields Meet Optical Spectroscopy: Probing Electronic Structure and Interaction Effects in Low-Dimensional Semiconductor- and Carbon-Based Structures
April 30Vivek ShenoyU PennCell-Matrix Interactions in 3D Microtissues: Multiscale Mechanical Models
May 7---