IJS KOLOKVIJ, 12.12.2007, prof. dr. Malcolm I. Heggie

[Marta Vidrih]

Vabim vas na 8. predavanje iz sklopa "Kolokviji na IJS" v letu 2007/08, ki bo v sredo, 12. decembra 2007, ob 13:00 uri v Veliki predavalnici Instituta >Jožef Stefan< na Jamovi cesti 39 v Ljubljani. Napovednik predavanja najdete tudi na naslovu http://www.ijs.si/ijsw/Koledar_prireditev, posnetke preteklih predavanj pa na http://videolectures.net/kolokviji_ijs. 

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Prof. dr. Malcolm I. Heggie:

 

Grafit - upognjen na novo



Ogljik je edinstven kemijski element z izredno bogato raznolikostjo alotropnih struktur. Tako na primer diamant in grafit posedujeta vrsto izjemnih fizikalnih in kemijskih lastnosti, ki so se v dvajsetem stoletju temeljito raziskale in tudi izkoristile v različnih aplikacijah. Odkritje fulerenov (1985) in nanocevk (1991) predstavlja neke vrste prelomnico v raziskavah ogljikovih struktur. V zapletenem svetu kristalnih defektov lahko podobne topološke prijeme uporabimo na grafitnih plasteh, ki jih zvijemo, prelomimo ali pa "zvarimo" v nove strukture. Opis tovrstnih defektov izhaja iz fizike dislokacij in njihove strukture lahko napovemo z uporabo DFT teorije. Identifikacija in karakterizacija dislokacij v grafitu nam odstre pogled v svet struktur, ki so bile poprej spregledane pri raziskavah grafita in še posebej v strukture, ki nastanejo pri obsevanju z visoko energijskimi nevtroni v reaktorjih.

Predavanje bo v angleščini.

http://www.sussex.ac.uk/chemistry/profile24753.htmlDepartment of Chemistry and Biochemistry, University of Sussex

Falmer, Brighton, UK

Lepo vabljeni!

 





 

We would like to invite you to 8th lecture of the "Kolokvij na IJS" in the school year 2007/08. The lecture will be held on Wednesday, Dec 12 2007, at 1 pm at JSI main lecture hall, Jamova 39, Ljubljana. The abstract of the lecture can be found on website: http://www.ijs.si/ijsw/Koledar_prireditev, the previous recorded lectures can be found on website: http://videolectures.net/kolokviji_ijs. 

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Professor dr. Malcolm I. Heggie:

 

Graphite - a new twist

 

Carbon is an element that is unique in the variety, utility and individuality of its allotropes. Diamond and graphite each have several uniquely extreme properties that have been exploited in twentieth century science and technology. Against the curious landscape of the periodic table the discoveries of fullerenes (1985) and nanotubes (1991) stand out as substantial landmarks. Their beauty lies in creating isolatable molecular forms. In the somewhat messier world of crystal defects, similar topological concepts can be applied, leading to sheets which are buckled, folded, 'welded' together, or unified into one sheet. The description of these defects comes from the science of dislocations, and their structures can be deduced from first principles methods, such as density functional theory (DFT). A connector between sheets, similar to the ramp connecting the floors of a multistorey car park, is a prismatic screw dislocation dipole. A fold is a pile-up of basal dislocation dipoles. The identification and characterization of dislocations in graphite, gives insight into structures which have been overlooked in the science of graphite, especially radiation damage which occurs in reactor graphite subjected to energetic neutrons.

 

The lecture will be given in English.


http://www.sussex.ac.uk/chemistry/profile24753.htmlDepartment of Chemistry and Biochemistry, University of Sussex

Falmer, Brighton, UK

 

We look forward to meeting you at the "Kolokvij na IJS"!



____________________________________
Marta Vidrih, univ.dipl.ekon.
F5 - Odsek za fiziko trdnih snovi
Institut "Jožef Stefan", Jamova 39, Ljubljana
tel: 01 477 39 02
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