1,184 research outputs found

    Photoemission evidence for crossover from Peierls-like to Mott-like transition in highly strained VO2_2

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    We present a spectroscopic study that reveals that the metal-insulator transition of strained VO2_2 thin films may be driven towards a purely electronic transition, which does not rely on the Peierls dimerization, by the application of mechanical strain. Comparison with a moderately strained system, which does involve the lattice, demonstrates the crossover from Peierls- to Mott-like transitions

    Strain dependence of bonding and hybridization across the metal-insulator transition of VO2

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    Soft x-ray spectroscopy is used to investigate the strain dependence of the metal-insulator transition of VO2. Changes in the strength of the V 3d - O 2p hybridization are observed across the transition, and are linked to the structural distortion. Furthermore, although the V-V dimerization is well-described by dynamical mean-field theory, the V-O hybridization is found to have an unexpectedly strong dependence on strain that is not predicted by band theory, emphasizing the relevance of the O ion to the physics of VO2

    Band anticrossing in GaNxSb1–x

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    Fourier transform infrared absorption measurements are presented from the dilute nitride semiconductor GaNSb with nitrogen incorporations between 0.2% and 1.0%. The divergence of transitions from the valence band to E– and E+ can be seen with increasing nitrogen incorporation, consistent with theoretical predictions. The GaNSb band structure has been modeled using a five-band k·p Hamiltonian and a band anticrossing fitting has been obtained using a nitrogen level of 0.78 eV above the valence band maximum and a coupling parameter of 2.6 eV

    Nature of the band gap of In2O3 revealed by first-principles calculations and x-ray spectroscopy

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    Bulk and surface sensitive x-ray spectroscopic techniques are applied in tandem to show that the valence band edge for In2O3 is found significantly closer to the bottom of the conduction band than expected on the basis of the widely quoted bulk band gap of 3.75 eV. First-principles theory shows that the upper valence bands of In2O3 exhibit a small dispersion and the conduction band minimum is positioned at Gamma. However, direct optical transitions give a minimal dipole intensity until 0.8 eV below the valence band maximum. The results set an upper limit on the fundamental band gap of 2.9 eV

    Band structure of ZnO from resonant x-ray emission spectroscopy

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    Soft x-ray emission and absorption spectroscopy of the O K-edge are employed to investigate the electronic structure of wurtzite ZnO(0001). A quasiparticle band structure calculated within the GW approximation agrees well with the data, most notably with the energetic location of the Zn3d - O2p hybridized state and the anisotropy of the absorption spectra. Dispersion in the band structure is mapped using the coherent k-selective part of the resonant x-ray emission spectra. We show that a more extensive mapping of the bands is possible in the case of crystalline anisotropy such as that found in ZnO.Comment: 5 pages, 5 figure

    Ligand-Receptor Interactions

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    The formation and dissociation of specific noncovalent interactions between a variety of macromolecules play a crucial role in the function of biological systems. During the last few years, three main lines of research led to a dramatic improvement of our understanding of these important phenomena. First, combination of genetic engineering and X ray cristallography made available a simultaneous knowledg of the precise structure and affinity of series or related ligand-receptor systems differing by a few well-defined atoms. Second, improvement of computer power and simulation techniques allowed extended exploration of the interaction of realistic macromolecules. Third, simultaneous development of a variety of techniques based on atomic force microscopy, hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or flexible transducers yielded direct experimental information of the behavior of single ligand receptor bonds. At the same time, investigation of well defined cellular models raised the interest of biologists to the kinetic and mechanical properties of cell membrane receptors. The aim of this review is to give a description of these advances that benefitted from a largely multidisciplinar approach

    Crop Updates - 2003 Pulses

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    This session covers fifty one papers from different authors 2002 PULSE INDUSTRY HIGHLIGHTS CONTRIBUTORS BACKGROUND 2002 REGIONAL ROUNDUP 1.Northern Agricultural Region, M. Harries, Department of Agriculture 2.Central agricultural Region, R. French and I. Pritchard, Department of Agriculture 3.Great Southern and Lakes, R. Beermier, N. Poulish and S. White, Department of Agriculture 4.Esperance Mallee, M. Seymour, Department of Agriculture PULSE PRODUCTION ECONOMY AND GENETIC IMPROVEMENT 5.Faba Bean, P. White, Department of Agriculture 6.Germplasm evaluation, P. White, T. Pope, M. Harries and M. Seymour, Department of Agriculture 7.Row spacing and sowing rate, M. Seymour, Department of Agriculture 8.Tolerance to post emergent herbicides, M. Seymour, M. Harries, R. Beermier, M. Blyth and L. Young, Department of Agriculture 9.Investigation of environmental staining and storage discolouration, N. Abbas1,2, J. Plummer1, P. White3, D. Harris4 and K. Siddique1,2, 1Plant Biology, The University of Western Australia, 2CLIMA, The University of Western Australia, 3Department of Agriculture, 4Chemistry Centre of Western Australia. Desi chickpea 10.Breeding highlights, T. Khan1,2 and K. Siddique2 1Department of Agriculture, 2CLIMA, The University of Western Australia 11. Variety evaluation, T. Khan and K. Regan, Department of Agriculture 12. Residual effect of chickpea row spacing and sowing rate on wheat yield, G. Riethmuller and B. MacLeod, Department of Agriculture 13. Genotype x environmental interaction studies to help explain adaptation, J. Berger1, N. Turner1,2, K. Siddique1, 1CLIMA, The University of Western Australia, 2CSIRO Plant Industry 14. Genetic characterisation of wild relatives, F. Shan and H. Clarke, CLIMA, The University of Western Australia 15. Tolerance to chilling at flowering, H. Clarke, CLIMA, The University of Western Australia 16. Kabuli chickpea, K. Regan, Department of Agriculture 17. Premium quality varieties for the Ord River Irrigation Area, K. Siddique1, K. Regan2 and P. Smith2 1CLIMA, The University of Western Australia, 2Department of Agriculture 18. Development of aschochyta resistant varieties for Australia, K. Siddique1, K. Regan2 and M. Baker2 1CLIMA, University of Western Australia, 2Department of Agriculture Field pea 19. Breeding highlights, T. Khan and B. French, Department of Agriculture 20. Variety evaluation, T. Khan, Department of Agriculture 21. Specialty types for the high rainfall regions, P. White and T. Khan, Department of Agriculture 22. Are new varieties more sensitive to delayed sowing than Dundale? R. French, M. Seymour and R. Beermier, Department of Agriculture 23. Does the size of sown seed affect seed size and yield at harvest? R. Beermier and N. Poulish, Department of Agriculture 24. Tolerance to post emergent herbicides, H. Dhammu, T. Piper and D. Nicholson, Department of Agriculture 25. Lentil, K. Regan, Department of Agriculture 26. Variety evaluation, K. Regan and M. Harries, Department of Agriculture 27. Interstate evaluation of advanced breeding lines, K. Regan1 and M. Materne2 1Department of Agriculture, 2Victorian Institute for Dryland Agriculture, Agriculture Victoria 28. Timing of harvest for the best seed yield, M. Harries and M. Blyth, Department of Agriculture 29. Tolerance to post emergent herbicides, M. Harries and D. Nicholson, Department of Agriculture, H. Dhammu, T. Piper and L. Young, Department of Agriculture 30. Row spacing and stubble, G. Riethmuller, Department of Agriculture Pulse species 31. High value pulses for the high rainfall areas, N. Poulish1, P. White1,2 and K. Siddique1,2 , 1Department of Agriculture, 2CLIMA, The University of Western Australia 32. Alternative Rhizobium inoculant carrier technologies, J. Howieson and R. Yates, Centre for Rhizobium Studies (CRS), Murdoch University 33. Time of harvest to improve seed yield and quality of pulses, G. Riethmuller and R. French, Department of Agriculture 34. Phosphorus and zinc responses in pulses, S. Loss1, Z. Rengel2, B. Bowden3, M. Bolland3 and K. Siddique4 , 1Wesfarmers CSBP, 2Soil Science and Plant Nutrition, The University of Western Australia, 3Department of Agriculture, 4CLIMA, The University of Western Australia 35. Robust protocols for doubled haploid production in field pea and chickpea, J. Croser and K. Siddique, CLIMA, The University of Western Australia DEMONSTRATION OF PULSES IN THE FARMING SYSTEM 36. Field pea and lentil on clayed sandplain, M. Seymour, Department of Agriculture 37. Field pea variety demonstration, M. Harries and M. Blyth, Department of Agriculture 38. The benefit of field peas compared to lupins, R. Beermier, Department of Agriculture DISEASE AND PEST MANAGEMENT 39. Ascochyta blight of chickpea, B. MacLeod, Department of Agriculture 40. Management of chickpeas with improved ascochyta resistance, B. Macleod, A. Harrod, M. Harries and M. Blyth, Department of Agriculture 41. Chlorothalonil provides the most effective control, B. Macleod, A. Harrod, M. Harries and M. Blyth, Department of Agriculture 42. Importance of early sprays and value of seed dressing (post emergence), B. Macleod and A. Harrod, Department of Agriculture 43. A windborne stage of ascochyta blight in WA, J. Galloway and B. MacLeod, Department of Agriculture Ascochyta disease of pulses 44. Geographic location effects ascochyta spore maturation on pulse stubble, J. Galloway and B. MacLeod, Department of Agriculture Blackspot of field pea 45. Rapid recurrent selection to improve resistance to black spot, C. Beeck1, J. Wroth1, W. Cowling1 and T. Khan2, 1Plant Science, The University of Western Australia, 2Department of Agriculture 46. Survival of blackspot on old field pea stubble, J. Galloway and B. MacLeod, Department of Agriculture 47. Blackspot spores mature earlier in the southern regions, M. Salam, J. Galloway, A. Diggle and B. MacLeod, Department of Agriculture Viruses in pulses 48. Early insecticide application suppresses spread of Beet Western Yellows virus in field pea, R. Jones, B. Coutts and L. Smith, Department of Agriculture, and CLIMA, The University of Western Australia Insect pests and nematodes 49. Incorporation of pea weevil resistance from Pisum fulvum into field pea, O. Byrne1 and D. Hardie2, 1CLIMA, The University of Western Australia 2Department of Agriculture 50. Resistance to Helicoverpa in wild species of chickpea, J. Ridsdill-Smith1, H. Sharma2 and K. Mann1, 1CSIRO Entomology, Western Australia, 2 ICRISAT, Hyderabad, India 51. Relative hosting ability of field pea genotypes to root lesion nematode, S. Kelly, S. Sharma, H. Hunter and V. Vanstone, Department of Agriculture ACKNOWLEDGEMENTS APPENDIX I: Publications by Pulse Productivity Project Staff 2002 APPENDIX II: Summary of previous results APPENDIX III: List of common acronym
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