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Levy G, Sutarto R, Chevrier D, Regier T, Blyth R, Geck J, Wurmehl S, Harnagea L, Wadati H, Mizokawa T, Elfimov IS, Damascelli A, Sawatzky GA. Probing the role of co substitution in the electronic structure of iron pnictides. Phys Rev Lett 2012; 109:077001. [PMID: 23006394 DOI: 10.1103/physrevlett.109.077001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Indexed: 06/01/2023]
Abstract
The role of Co substitution in the low-energy electronic structure of Ca(Fe(0.944)Co(0.056))(2)As(2) is investigated by resonant photoemission spectroscopy and density-functional theory. The Co 3d state center of mass is observed at 250 meV higher binding energy than that of Fe, indicating that Co possesses one extra valence electron and that Fe and Co are in the same oxidation state. Yet, significant Co character is detected for the Bloch wave functions at the chemical potential, revealing that the Co 3d electrons are part of the Fermi sea determining the Fermi surface. This establishes the complex role of Co substitution in CaFe(2)As(2) and the inadequacy of a rigid-band shift description.
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Affiliation(s)
- G Levy
- Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada.
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Li YS, Tang Y, Yang Q, Maley J, Sammynaiken R, Regier T, Xiao C, Hirose A. Ultrathin W-Al dual interlayer approach to depositing smooth and adherent nanocrystalline diamond films on stainless steel. ACS Appl Mater Interfaces 2010; 2:335-338. [PMID: 20356176 DOI: 10.1021/am9007159] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The adherence of diamond coated on steel is commonly low and needs to be strengthened with thick intermediate layers. In this paper, a nanoscale W-Al dual metal interlayer has been applied on SS304 substrates to facilitate deposition of continuous, adherent and smooth diamond thin films. During the microwave plasma-enhanced chemical vapor deposition process, the Al inner layer 30 nm thick diffuses into steel surface inhibiting carbon diffusion and graphitization. The W outer layer 20 nm thick is transformed into W carbides, both preventing carbon diffusion and enhancing diamond nucleation. The diamond films synthesized are of high purity and have smooth surfaces and dense structures. Indentation and shear deformation tests indicate high delaminating tolerance of the diamond films.
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Wilks RG, MacNaughton JB, Kraatz HB, Regier T, Blyth RIR, Moewes A. Comparative Theoretical and Experimental Study of the Radiation-Induced Decomposition of Glycine. J Phys Chem A 2009; 113:5360-6. [DOI: 10.1021/jp900794v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- R. G. Wilks
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - J. B. MacNaughton
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - H.-B. Kraatz
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - T. Regier
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - R. I. R. Blyth
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
| | - A. Moewes
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan, S7N 5E2, Canada
- Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario, N6A 5B7, Canada
- Canadian Light Source Inc., University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan, S7N 0X4, Canada
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Zhou XT, Zhou JG, Murphy MW, Ko JYP, Heigl F, Regier T, Blyth RIR, Sham TK. The effect of the surface of SnO2 nanoribbons on their luminescence using x-ray absorption and luminescence spectroscopy. J Chem Phys 2008; 128:144703. [DOI: 10.1063/1.2841419] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Otero E, Wilks RG, Regier T, Blyth RIR, Moewes A, Urquhart SG. Substituent Effects in the Iron 2p and Carbon 1s Edge Near-Edge X-ray Absorption Fine Structure (NEXAFS) Spectroscopy of Ferrocene Compounds. J Phys Chem A 2008; 112:624-34. [DOI: 10.1021/jp074625w] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- E. Otero
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - R. G. Wilks
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - T. Regier
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - R. I. R. Blyth
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - A. Moewes
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
| | - S. G. Urquhart
- Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada, and Canadian Light Source, University of Saskatchewan, 101 Perimeter Road, Saskatoon, Saskatchewan S7N 0X4, Canada
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Drivonikou GV, Kay P, Regier T, Ivry RB, Gilbert AL, Franklin A, Davies IRL. Further evidence that Whorfian effects are stronger in the right visual field than the left. Proc Natl Acad Sci U S A 2007; 104:1097-102. [PMID: 17213312 PMCID: PMC1783370 DOI: 10.1073/pnas.0610132104] [Citation(s) in RCA: 108] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Whorf hypothesis holds that differences between languages induce differences in perception and/or cognition in their speakers. Much of the experimental work pursuing this idea has focused on the domain of color and has centered on the issue of whether linguistically coded color categories influence color discrimination. A new perspective has been cast on the debate by recent results that suggest that language influences color discrimination strongly in the right visual field but not in the left visual field (LVF). This asymmetry is likely related to the contralateral projection of visual fields to cerebral hemispheres and the specialization of the left hemisphere for language. The current study presents three independent experiments that replicate and extend these earlier results by using different tasks and testing across different color category boundaries. Our results differ in one respect: although we find that Whorfian effects on color are stronger for stimuli in the right visual field than in the LVF, we find that there are significant category effects in the LVF as well. The origin of the significant category effect in the LVF is considered, and two factors that might account for the pattern of results are proposed.
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Affiliation(s)
- G. V. Drivonikou
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - P. Kay
- International Computer Science Institute, 1947 Center Street, Berkeley, CA 94704
- Department of Linguistics and
- To whom correspondence may be addressed. E-mail:
or
| | - T. Regier
- Helen Wills Neuroscience Institute and Department of Psychology, University of Calfornia, Berkeley, CA 94720; and
| | - R. B. Ivry
- Department of Psychology, The University of Chicago, Chicago, IL 60637
| | - A. L. Gilbert
- Department of Psychology, The University of Chicago, Chicago, IL 60637
| | - A. Franklin
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
| | - I. R. L. Davies
- Department of Psychology, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom
- To whom correspondence may be addressed. E-mail:
or
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Regier T, Paulsen J, Wright G, Coulthard I, Tan K, Sham TK, Blyth RIR. Commissioning of the Spherical Grating Monochromator Soft X-ray Spectroscopy Beamline at the Canadian Light Source. ACTA ACUST UNITED AC 2007. [DOI: 10.1063/1.2436101] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Heigl F, Jürgensen A, Zhou XT, Lam S, Murphy M, Ko JYP, Sham TK, Rosenberg RA, Gordon R, Brewe D, Regier T, Armelao L. Dynamic View on Nanostructures: A Technique for Time Resolved Optical Luminescence using Synchrotron Light Pulses at SRC, APS, and CLS. ACTA ACUST UNITED AC 2007. [DOI: 10.1063/1.2436279] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Wilks RG, MacNaughton JB, Kraatz HB, Regier T, Moewes A. Combined X-ray Absorption Spectroscopy and Density Functional Theory Examination of Ferrocene-Labeled Peptides. J Phys Chem B 2006; 110:5955-65. [PMID: 16553403 DOI: 10.1021/jp056573l] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A combination of soft X-ray absorption spectroscopy (XAS) measurements and StoBe density functional theory (DFT) calculations has been used to study the electronic structures of the ferrocene-labeled peptides Fc-Pro(n)-OBz (n = 1-4). Excellent agreement between the measured and the simulated data is observed in all cases, and the origin of all major spectral features was assigned. The breaking of the degeneracy of the ferrocene 3e(2u)-like unoccupied molecular orbital under the influence of a substituent attached to a Cp ring was observed experimentally. The influence of the bonding environment on the O 1s and N 1s XAS spectra was examined. A corrected assignment of one of the major features in the Fe 2p XAS spectra of ferrocene is proposed and supported by the DFT simulations, as well as the measured spectra.
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Affiliation(s)
- R G Wilks
- Department of Physics and Engineering Physics, University of Saskatchewan, 116 Science Place, Saskatoon, Saskatchewan S7N 5E2, Canada.
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Abstract
The present paper grounds the linguistic cdategorization of space in aspects of visual perception; specifically, the structure of projective spatial terms such as above are grounded in the process of attention and in vector-sum coding of overall direction. This is formalized in the attentional vector-sum (AVS) model. This computational model accurately predicts linguistic acceptability judgments for spatial terms, under a variety of spatial configurations. In 7 experiments, the predictions of the AVS model are tested against those of 3 competing models. The results support the AVS model and disconfirm its competitors. The authors conclude that the structure of linguistic spatial categories can be partially explained in terms of independently motivated perceptual processes.
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Affiliation(s)
- T Regier
- Department of Psychology, University of Chicago, Green 414, 5848 South University Avenue, Chicago, Illinois 60637, USA
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Abstract
The present paper grounds the linguistic cdategorization of space in aspects of visual perception; specifically, the structure of projective spatial terms such as above are grounded in the process of attention and in vector-sum coding of overall direction. This is formalized in the attentional vector-sum (AVS) model. This computational model accurately predicts linguistic acceptability judgments for spatial terms, under a variety of spatial configurations. In 7 experiments, the predictions of the AVS model are tested against those of 3 competing models. The results support the AVS model and disconfirm its competitors. The authors conclude that the structure of linguistic spatial categories can be partially explained in terms of independently motivated perceptual processes.
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Affiliation(s)
- T Regier
- Department of Psychology, University of Chicago, Green 414, 5848 South University Avenue, Chicago, Illinois 60637, USA
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Abstract
Three experiments examine the relation between linguistic and non-linguistic categorization of spatial relations. We compare linguistic and non-linguistic responses to the same spatial stimuli. Contrary to earlier claims in the literature (Hayward, W. G. & Tarr, M. J. (1995). Spatial language and spatial representation. Cognition, 55, 39-84), we find that linguistic and non-linguistic spatial categories do not correspond. Rather, they appear to have an inverse relation such that the prototypes of linguistic categories, such as 'above', are boundaries in non-linguistic spatial categorization. Evidence for this inverse relation comes from linguistic acceptability judgments and the pattern of bias in participants' reproductions of location. Our findings suggest that while linguistic and non-linguistic spatial organization rely on a common underlying structure, that structure may play different roles in the two organizational systems.
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Affiliation(s)
- L E Crawford
- Department of Psychology, University of Chicago, 5848 S. University Avenue, Chicago 60615, USA.
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