TcSUH EventS
Special Seminar
Solid State Metathesis Reactions as a Conceptual Tool in the Synthesis of New Materials
by: Prof. H. -J. Meyer
Date: Friday March 25, 2011
Time: 12:00 pm – 1:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
Solid state metathesis reactions can be used in the syntheses of inorganic solids and for strategic design of novel, eventually thermally labile materials. An explorative study of solid state metathesis reactions is presented for a number of examples, including syntheses of nitridoborates, carbodiimides, tetracyanoborates, tetracyanamidosilicates, carbon-nitride materials, and a number of other exciting compounds. This unique type of reaction is very efficient because it uses the intrinsic energy of reaction partners being involved. Desired compositions are achieved by appropriate starting materials and their relative amounts being combined into a solid state metathesis reaction. Reactions can be controlled through the heating-up procedure and by using a reactive flux, which may lower the ignition temperature of a reaction mixture and promote crystal growth of products.
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Special Seminar
Magneto-Optical Properties of Graphene Layers: a Tight-Binding Study
by: Dr. Yen-Hung Ho
Date: Thursday March 10, 2011
Time: 12:00 pm – 1:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
A complete tight-binding model is developed to study the electronic and optical properties of graphene layers in response to magnetic field. Since the magnetic field and all atomic hoppings are simultaneously taken into account without introducing any approximation, the calculated results are accurate over a wide energy range. The wave functions and their spatial distributions appropriately characterize the Landau levels. Moreover, the concept of sublattices provides a straightforward way to clearly identify the optical spectra, including the selection rules and relative absorption rates. The spectral structures are substantially impacted by the interlayer interactions and the stacking sequence. Our numerical results can provide guideline and new spectral features for future experiments.
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Special Seminar
What Kind of Stars Made the Calcium in your Bones?
by: Dr. Typhoon Lee
Date: Tuesday March 08, 2011
Time: 4:00 pm – 5:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
The Ca in our body were all made in other stars that contributed ejecta from their nuclearly processed interior to the proto-solar molecular cloud. The subsequent evolution will change the elemental ratios but not isotope ratios. Thus the six stable isotopes of Calcium (Ca-40, 42, 43, 44, 46, and 48 plus the radioactive Ca-41) constitute an extremely powerful tool to trace the nuclear astrophysical origin of the building material used to make our planetary system and ourselves. I will show that several processes in supernova type I and type II as well as AGB stars were involved. I will also show the most up-to-date high precision data for the earliest solid in the solar system. They not only gave us lots of insight in the late stage evolution of massive stars but also seduce us to speculate on the last minute contamination from a neaby supernova just when the planetesimals were accreting into planets.
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Joint Colloquim
Mike Gorman's Flame
by: Prof. Norm Frankel
Date: Tuesday March 01, 2011
Time: 4:00 pm – 6:00 pm
Location: Science & Research Building 1 – Building 550 — Room 634
Overview
Two of Mike's forte were the physics of flames and nonlinear dynamics of fluids inclusive of turbulence. This talk, to honor Mike, will be half on the former and half on the latter. It will be a "light" presentation within physics and personal realms.
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Joint Colloquim
String Theory and D-brane charge
by: Dr. Wilberth Herrera
Date: Tuesday March 01, 2011
Time: 10:00 am – 6:00 pm
Location: Houston Science Center – Building 593 — Room 102
Overview
In the late 60's and early 70's , when String Theory was proposed, it was intended to explain the gravitational force at the quantum level, ie. a theory of quantum gravity. Initially String Theory included only strings as its basic mathematical objects. Today, in its modern incarnation, String Theory includes a number of different and exotic objects. One important example are D-branes, which are relevant when one wants to talk about string dynamics and interactions. One of the properties of D-branes is their charge, analogous to the electrical charge of the electron. In this talk we will discuss the mathematical framework to "measure" this charge and some consequences of this property.
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