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Viewing upcoming talks containing the keyword: 4
Speaker: D Flemming Hansen (UCL)
NMR spectroscopy is a powerful technique to characterise the structural dynamics of proteins over many time-scales. Several recently developed NMR methods to characterise protein dynamics will be presented in the talk. These include methods to characterise the structure and dynamics of low-populated and excited states of proteins, as well as methods to characterise protein side-chains dynamics and potassium binding in medium-large proteins. Applications of the recently developed methods to the histone deacetylase enzymes will also be presented.
On: April 27, 2016 From: 15h30 To: 16h30View talk
Speaker: Jim Scott (St Andrews)
Thin-film ferroelectric oxides have become in the past three years the basis of commercial memory devices in Korea, Japan, and the USA, largely for transit fare cards (brand name "Felica" -- similar to the London "oyster card") and cash machines (brand name "Edy") at ca. £100 million/year. Much of this technology was developed in my US university laboratory in the 1980s (hence unfortunately the patent royalties stopped long ago!). I will describe the solid state chemistry of this project and our present work here in the School of Chemistry on multiferroics (ferroelectric ferromagnets) that is trying to combine the best attributes of ferroelectric FRAMs with magnetic MRAMs (RAM = random access memory). The main aim is to discover or invent materials that are ferroelectric and ferromagnetic at ROOM TEMPERATURE (very rare) and are cheap and non-toxic. New favorites include hexaferrites (Ba- or SrFe12O19), gallium orthoferrite GaFeO3, and the ternary perovskites PbFe(1/2)M(1/2)O3Ta(x)Zr(1-x) [M=Ta,Nb].
On: April 29, 2016 From: 14h00 To: 15h00View talk
Speaker: Prof Jun Yuan (York)
Electron microscopy and associated spectroscopy are very powerful imaging and analytical techniques for the study of atomic structure of materials, particularly after the development of aberration correction and monochromator. In the first part of this talk, I will show how we can take advantage of the improved spatial resolution and better understanding of the image formation physics to achieve quantitative atomic structure imaging. The examples will include the 3D structural determination of gold nanocatalysts; the local chemical ordering in nanoalloys and adatom dynamics on two-dimensional materials. In the second part of the talk, I will introduce some applications of spatially and angular resolved electron energy loss spectroscopy (EELS) in nanomaterials research. Finally, I will also show some emerging microscopic studies based on novel electron vortex beams, demonstrating controlled nanoparticles manipulation inside electron microscopy.
On: May 3, 2016 From: 15h30 To: 16h30View talk
Speaker: David Leigh (Manchester)
Over the past few years some of the first examples of synthetic molecular level machines and motors—all be they primitive by biological standards—have been developed.These molecules respond to light, chemical and electrical stimuli, inducing motion of interlocked components held together by hydrogen bonding or other weak molecular interactions.
Perhaps the best way to appreciate the technological potential of controlled molecular-level motion is to recognise that nanomotors and molecular-level machines lie at the heart of every significant biological process. Over billions of years of evolution Nature has not repeatedly chosen this solution for achieving complex task performance without good reason. In stark contrast to biology, none of mankind’s fantastic myriad of present day technologies exploit controlled molecular-level motion in any way at all: every catalyst, every material, every polymer, every pharmaceutical, every chemical reagent, all function exclusively through their static or equilibrium dynamic properties. When we learn how to build artificial structures that can control and exploit molecular level motion, and interface their effects directly with other molecular-level substructures and the outside world, it will potentially impact on every aspect of functional molecule and materials design. An improved understanding of physics and biology will surely follow.
"Pick-up, Transport and Release of a Molecular Cargo using a Small-Molecule Robotic Arm" Nature Chem, 8, 138-143 (2016) • "A Star of David Catenane" Nature Chem, 6, 978-982 (2014) • "Sequence-Specific Peptide Synthesis by an Artificial Small-Molecule Machine" Science, 339, 189-193 (2013) • "A Synthetic Molecular Pentafoil Knot" Nature Chem, 4, 15-20 (2012) • "A Single Synthetic Small Molecule that Generates Force Against a Load" Nature Nanotech, 6, 553-557 (2011) • "A Synthetic Small Molecule That Can Walk Down a Track" Nature Chem, 2, 96-101 (2010) • "Operation Mechanism of a Molecular Machine Revealed Using Time-Resolved Vibrational Spectroscopy" Science, 328, 1255-1258 (2010) • "Hybrid Organic-Inorganic Rotaxanes and Molecular Shuttles" Nature, 458, 314-318 (2009) • "A Molecular Information Ratchet" Nature, 445, 523-527 (2007) • "Macroscopic Transport by Synthetic Molecular Machines" Nature Mater, 4, 704-710 (2005) • "A Reversible Synthetic Rotary Molecular Motor" Science, 306, 1532-1537 (2004) • "Unidirectional Rotation in a Mechanically Interlocked Molecular Rotor" Nature, 424, 174-179 (2003) •
On: May 4, 2016 From: 15h30 To: 16h30View talk
Cond Mat Seminars
Speaker: Feliciano Giustino (Oxford University)
The interaction between electrons and bosons is a central concept in condensed matter physics. For example, the signatures of electron-phonon interactions are ubiquitous in photoelectron spectra, light absorption, emission, and scattering spectra, as well as electron tunneling spectra. Until recently the theoretical analysis of such interactions and their consequences could only be carried out using empirical models such as the classic Froehlich Hamiltonian. However, during the past decade, the development of new computational techniques and new theoretical approaches have enabled the study of electron-boson interactions entirely from first principles. In this talk I will discuss two very recent examples of first-principles calculations of electron-boson interactions. In the first example I will discuss the interactions between electrons and plasmons, that is electron charge-density fluctuations. We recently found that this interaction leads to the emergence of novel features in the band structures of semiconductors, which can be described as broadened replicas of the standard valence bands, with a binding energy blue-shifted by the energy of the plasmon excitation . We called these new features 'plasmonic polarons' and we predicted their existence in standard tetrahedral semiconductors as well as two-dimensional transition metal dichalcogenides. Recent experiments confirmed the existence of such features in silicon. In the second example I will discuss recent work on the interaction between electrons and polar optical phonons in titanium dioxide . Here we succeeded in reproducing entirely from first principles recent angle-resolved photoemission data on anatase titanium dioxide. Our analysis allowed us to identify the atomistic origin of the polaron satellites observed in the experiments, and constitutes the first step towards fully ab-initio calculations of polarons in complex oxides. F. Caruso, H. Lambert, and F. Giustino, Phys. Rev. Lett. 114, 146404 (2015). C. Verdi and F. Giustino, Phys. Rev. Lett. 115, 176401 (2015).
On: May 4, 2016 From: 13h00 To: 14h00View talk