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Author |
Bertrand, L.; Robinet, L.; Thoury, M.; Janssens, K.; Cohen, S.X.; Schöder, S. |
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Title |
Cultural heritage and archaeology materials studied by synchrotron spectroscopy and imaging |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Applied physics A : materials science & processing |
Abbreviated Journal |
Appl Phys A-Mater |
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Volume |
106 |
Issue |
2 |
Pages |
377-396 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The use of synchrotron radiation techniques to study cultural heritage and archaeological materials has undergone a steep increase over the past 10-15 years. The range of materials studied is very broad and encompasses painting materials, stone, glass, ceramics, metals, cellulosic and wooden materials, and a cluster of organic-based materials, in phase with the diversity observed at archaeological sites, museums, historical buildings, etc. Main areas of investigation are: (1) the study of the alteration and corrosion processes, for which the unique non-destructive speciation capabilities of X-ray absorption have proved very beneficial, (2) the understanding of the technologies and identification of the raw materials used to produce archaeological artefacts and art objects and, to a lesser extent, (3) the investigation of current or novel stabilisation, conservation and restoration practices. In terms of the synchrotron methods used, the main focus so far has been on X-ray techniques, primarily X-ray fluorescence, absorption and diffraction, and Fourier-transform infrared spectroscopy. We review here the use of these techniques from recent works published in the field demonstrating the breadth of applications and future potential offered by third generation synchrotron techniques. New developments in imaging and advanced spectroscopy, included in the UV/visible and IR ranges, could even broaden the variety of materials studied, in particular by fostering more studies on organic and complex organic-inorganic mixtures, while new support activities at synchrotron facilities might facilitate transfer of knowledge between synchrotron specialists and users from archaeology and cultural heritage sciences. |
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Wos |
000299749000009 |
Publication Date |
2011-11-25 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0947-8396 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.455 |
Times cited |
55 |
Open Access |
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Notes |
; The authors acknowledge the critical reading by B. Berrie (National Gallery of Art, Washington DC, USA). We thank J. Mass (Conservation Department, Winterthur Museum and Country Estate, Winterthur, DE, USA), H. Roemich (Institute of Fine Arts, New York University, USA), J. Hiller (Non-Crystalline Diffraction Beamline, Diamond Light Source, Didcot, UK) and J.-P. Echard (Laboratoire de recherche et de restauration, Musee de la musique, Paris, France) for their comments on the presentation of their work in the manuscript. The IPANEMA platform is jointly developed by CNRS, MNHN, the French Ministry of Culture and Communication and SOLEIL, and benefits from a CPER grant (MESR, Region Ile-de-France). Support by the Access to Research Infrastructures activity in the 7th Framework Programme of the EU (CHARISMA Grant Agreement n. 228330) and the NWO Science4Arts programme are acknowledged. ; |
Approved |
Most recent IF: 1.455; 2012 IF: 1.545 |
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Call Number |
UA @ admin @ c:irua:99166 |
Serial |
5561 |
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Permanent link to this record |
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Author |
De Backer, L.A.; Vos, W.G.; Salgado, R.; de Backer, J.W.; Devolder, A.; Verhulst, S.L.; Claes, R.; Germonpré, P.R.; de Backer, W.A. |
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Title |
Functional imaging using computer methods to compare the effect of salbutamol and ipratropium bromide in patient-specific airway models of COPD |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
International journal of chronic obstructive pulmonary disease |
Abbreviated Journal |
Int J Chronic Obstr |
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Volume |
6 |
Issue |
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Pages |
637-646 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Vision lab; Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
Background: Salbutamol and ipratropium bromide improve lung function in patients with chronic obstructive pulmonary disease (COPD). However, their bronchodilating effect has not yet been compared in the central and distal airways. Functional imaging using computational fluid dynamics offers the possibility of making such a comparison. The objective of this study was to assess the effects of salbutamol and ipratropium bromide on the geometry and computational fluid dynamics-based resistance of the central and distal airways.Methods: Five patients with Global Initiative for Chronic Obstructive Lung Disease Stage III COPD were randomized to a single dose of salbutamol or ipratropium bromide in a crossover manner with a 1-week interval between treatments. Patients underwent lung function testing and a multislice computed tomography scan of the thorax that was used for functional imaging. Two hours after dosing, the patients again underwent lung function tests and repeat computed tomography.Results: Lung function parameters, including forced expiratory volume in 1 second, vital capacity, overall airway resistance, and specific airway resistance, changed significantly after administration of each product. On functional imaging, the bronchodilating effect was greater in the distal airways, with a corresponding drop in airway resistance, compared with the central airways. Salbutamol and ipratropium bromide were equally effective at first glance when looking at lung function tests, but when viewed in more detail with functional imaging, hyporesponsiveness could be shown for salbutamol in one patient. Salbutamol was more effective in the other patients.Conclusion: This pilot study gives an innovative insight into the modes of action of salbutamol and ipratropium bromide in patients with COPD, using the new techniques of functional imaging and computational fluid dynamics. |
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Wos |
000208709800068 |
Publication Date |
2011-11-28 |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1178-2005; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.157 |
Times cited |
25 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.157; 2011 IF: NA |
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Call Number |
UA @ lucian @ c:irua:93165 |
Serial |
1300 |
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Permanent link to this record |
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Author |
Neyts, E.C.; van Duin, A.C.T.; Bogaerts, A. |
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Title |
Insights in the plasma-assisted growth of carbon nanotubes through atomic scale simulations : effect of electric field |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of the American Chemical Society |
Abbreviated Journal |
J Am Chem Soc |
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Volume |
134 |
Issue |
2 |
Pages |
1256-1260 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Carbon nanotubes (CNTs) are nowadays routinely grown in a thermal CVD setup. State-of-the-art plasma-enhanced CVD (PECVD) growth, however, offers advantages over thermal CVD. A lower growth temperature and the growth of aligned freestanding single-walled CNTs (SWNTs) makes the technique very attractive. The atomic scale growth mechanisms of PECVD CNT growth, however, remain currently entirely unexplored. In this contribution, we employed molecular dynamics simulations to focus on the effect of applying an electric field on the SWNT growth process, as one of the effects coming into play in PECVD. Using sufficiently strong fields results in (a) alignment of the growing SWNTs, (b) a better ordering of the carbon network, and (c) a higher growth rate relative to thermal growth rate. We suggest that these effects are due to the small charge transfer occurring in the Ni/C system. These simulations constitute the first study of PECVD growth of SWNTs on the atomic level. |
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Place of Publication |
Washington, D.C. |
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Wos |
000301084300086 |
Publication Date |
2011-11-30 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0002-7863;1520-5126; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.858 |
Times cited |
56 |
Open Access |
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Notes |
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Approved |
Most recent IF: 13.858; 2012 IF: 10.677 |
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Call Number |
UA @ lucian @ c:irua:97163 |
Serial |
1673 |
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Permanent link to this record |
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Author |
Pham, A.-T.; Sorée, B.; Magnus, W.; Jungemann, C.; Meinerzhagen, B.; Pourtois, G. |
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Title |
Quantum simulations of electrostatics in Si cylindrical junctionless nanowire nFETs and pFETs with a homogeneous channel including strain and arbitrary crystallographic orientations |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Solid state electronics |
Abbreviated Journal |
Solid State Electron |
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Volume |
71 |
Issue |
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Pages |
30-36 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
Simulation results of electrostatics in Si cylindrical junctionless nanowire transistors with a homogenous channel are presented. Junctionless transistors including strain and arbitrary crystallographic orientations are studied. Size quantization effects are simulated by self-consistent solutions of the Poisson and Schrodinger equations. The 6 x 6 k.p method is employed for the calculation of the valence subband structure in a junctionless nanowire pFET. The influence of stress/strain and crystallographic channel orientation on to the electrostatics in terms of subband structure, charge density, and C-V curve is systematically studied. (C) 2011 Elsevier Ltd. All rights reserved. |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000303033800007 |
Publication Date |
2011-12-01 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0038-1101; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.58 |
Times cited |
2 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 1.58; 2012 IF: 1.482 |
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Call Number |
UA @ lucian @ c:irua:98245 |
Serial |
2786 |
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Permanent link to this record |
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Author |
Delabie, A.; Sioncke, S.; Rip, J.; Van Elshocht, S.; Pourtois, G.; Mueller, M.; Beckhoff, B.; Pierloot, K. |
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Title |
Reaction mechanisms for atomic layer deposition of aluminum oxide on semiconductor substrates |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of vacuum science and technology: A: vacuum surfaces and films |
Abbreviated Journal |
J Vac Sci Technol A |
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Volume |
30 |
Issue |
1 |
Pages |
01a127-01a127,10 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
In this work, we have studied the TMA/H(2)O (TMA Al(CH(3))(3)) atomic layer deposition (ALD) of Al(2)O(3) on hydroxyl (OH) and thiol (SH) terminated semiconductor substrates. Total reflection x-ray fluorescence reveals a complex growth-per-cycle evolution during the early ALD reaction cycles. OH and SH terminated surfaces demonstrate growth inhibition from the second reaction cycle on. Theoretical calculations, based on density functional theory, are performed on cluster models to investigate the first TMA/H(2)O reaction cycle. Based on the theoretical results, we discuss possible mechanisms for the growth inhibition from the second reaction cycle on. In addition, our calculations show that AlCH(3) groups are hydrolyzed by a H(2)O molecule adsorbed on a neighboring Al atom, independent of the type of backbonds (Si-O, Ge-O, or Ge-S) of AlCH(3). The coordination of Al remains four-fold after the first TMA/H(2)O reaction cycle. (C) 2012 American Vacuum Society. [DOI: 10.1116/1.3664090] |
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Place of Publication |
New York, N.Y. |
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Wos |
000298992800027 |
Publication Date |
2011-12-02 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0734-2101; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.374 |
Times cited |
41 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.374; 2012 IF: 1.432 |
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Call Number |
UA @ lucian @ c:irua:96253 |
Serial |
2818 |
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Permanent link to this record |
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Author |
Kirilenko, D.A.; Dideykin, A.T.; Van Tendeloo, G. |
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Title |
Measuring the corrugation amplitude of suspended and supported graphene |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
23 |
Pages |
235417-235417,5 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Nanoscale corrugation is a fundamental property of graphene arising from its low-dimensional nature. It places a fundamental limit to the conductivity of graphene and influences its properties. However the degree of the influence of the corrugation has not been well established because of the little knowledge about its spectrum in suspended graphene. We present a transmission electron microscopy technique that enables us to measure the average corrugation height and length. We applied the technique also to measure the temperature dependence of the corrugation. The difference in corrugation between suspended and supported graphene has been illustrated. |
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Wos |
000297764700003 |
Publication Date |
2011-12-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93629 |
Serial |
1971 |
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Permanent link to this record |
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Author |
De Trizio, L.; Figuerola, A.; Manna, L.; Genovese, A.; George, C.; Brescia, R.; Saghi, Z.; Simonutti, R.; van Huis, M.; Falqui, A. |
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Title |
Size-tunable, hexagonal plate-like Cu3P and Janus-like Cu-Cu3P nanocrystals |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
ACS nano |
Abbreviated Journal |
Acs Nano |
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Volume |
6 |
Issue |
1 |
Pages |
32-41 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
We describe two synthesis approaches to colloidal Cu3P nanocrystals using trioctylphosphine (TOP) as phosphorus precursor. One approach is based on the homogeneous nucleation of small Cu3P nanocrystals with hexagonal plate-like morphology and with sizes that can be tuned from 5 to 50 nm depending on the reaction time. In the other approach, metallic Cu nanocrystals are nucleated first and then they are progressively phosphorized to Cu3P. In this case, intermediate Janus-like dimeric nanoparticles can be isolated, which are made of two domains of different materials, Cu and Cu3P, sharing a flat epitaxial interface. The Janus-like nanoparticles can be transformed back to single-crystalline copper particles if they are annealed at high temperature under high vacuum conditions, which makes them an interesting source of phosphorus. The features of the Cu Cu3P Janus-like nanoparticles are compared with those of the Wiped microstructure discovered more than two decades ago in the rapidly quenched Cu Cu3P eutectic of the Cu P alloy, suggesting that other alloy/eutectic systems that display similar behavior might give origin to nanostructures with flat, epitaxial Interface between domains of two diverse materials. Finally, the electrochemical properties of the copper phosphide plates are studied, and they are found to be capable of undergoing lithiation/delithiation through a displacement reaction, while the Janus-like Cu Cu3P particles do not display an electrochemical behavior that would make them suitable for applications in batteries. |
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Wos |
000299368300006 |
Publication Date |
2011-12-03 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1936-0851;1936-086X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
13.942 |
Times cited |
60 |
Open Access |
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Notes |
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Approved |
Most recent IF: 13.942; 2012 IF: 12.062 |
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Call Number |
UA @ lucian @ c:irua:99172 |
Serial |
3039 |
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Permanent link to this record |
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Author |
Gao, J.; Lebedev, O.I.; Turner, S.; Li, Y.F.; Lu, Y.H.; Feng, Y.P.; Boullay, P.; Prellier, W.; Van Tendeloo, G.; Wu, T. |
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Title |
Phase selection enabled formation of abrupt axial heterojunctions in branched oxide nanowires |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Nano letters |
Abbreviated Journal |
Nano Lett |
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Volume |
12 |
Issue |
1 |
Pages |
275-280 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Rational synthesis of nanowires via the vaporliquidsolid (VLS) mechanism with compositional and structural controls is vitally important for fabricating functional nanodevices from bottom up. Here, we show that branched indium tin oxide nanowires can be in situ seeded in vapor transport growth using tailored AuCu alloys as catalyst. Furthermore, we demonstrate that VLS synthesis gives unprecedented freedom to navigate the ternary InSnO phase diagram, and a rare and bulk-unstable cubic phase can be selectively stabilized in nanowires. The stabilized cubic fluorite phase possesses an unusual almost equimolar concentration of In and Sn, forming a defect-free epitaxial interface with the conventional bixbyite phase of tin-doped indium oxide that is the most employed transparent conducting oxide. This rational methodology of selecting phases and making abrupt axial heterojunctions in nanowires presents advantages over the conventional synthesis routes, promising novel composition-modulated nanomaterials. |
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Publisher |
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Place of Publication |
Washington |
Editor |
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Wos |
000298943100048 |
Publication Date |
2011-12-05 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1530-6984;1530-6992; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
12.712 |
Times cited |
25 |
Open Access |
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Notes |
Fwo |
Approved |
Most recent IF: 12.712; 2012 IF: 13.025 |
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Call Number |
UA @ lucian @ c:irua:94209 |
Serial |
2587 |
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Permanent link to this record |
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Author |
Piñera, I.; Cruz, C.M.; van Espen, P.; Abreu, Y.; Leyva, A. |
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Title |
Study of dpa distributions in electron irradiated YBCO slabs through MCCM algorithm |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Nuclear instruments and methods in physics research: B: beam interactions with materials and atoms |
Abbreviated Journal |
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Volume |
274 |
Issue |
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Pages |
191-194 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
The Monte Carlo assisted Classical Method (MCCM) consists on a calculation procedure for determining the displacements per atom (dpa) distribution in solid materials. This algorithm allows studying the gamma and electron irradiation damage in different materials. It is based on the electrons elastic scattering classic theories and the use of Monte Carlo simulation for the physical processes involved. The present study deals with the Monte Carlo simulation of electron irradiation effects on YBa2Cu3O7-x (YBCO) slabs using the MCNPX code system. Displacements per atom distributions are obtained through the MCCM for electron irradiation up to 10 MeV. In-depth dpa profiles for electrons and positrons are obtained and analysed. Also, dpa contributions from each atomic specie in the material are calculated. It was found that the dpa distribution is more homogeneous in the material volume when increasing energy of incident electrons. Also, the dpa produced by positrons has no relevance when irradiating with electrons, in contrast with previous similar gamma irradiation studies. All the results are presented and discussed in this contribution. (C) 2011 Elsevier B.V. All rights reserved. |
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Wos |
000301611900031 |
Publication Date |
2011-12-05 |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0168-583x |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:97819 |
Serial |
8595 |
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Permanent link to this record |
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Author |
Covaci, L.; Peeters, F.M. |
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Title |
Superconducting proximity effect in graphene under inhomogeneous strain |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
24 |
Pages |
241401-241401,4 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The interplay between quantum Hall states and Cooper pairs is usually hindered by the suppression of the superconducting state due to the strong magnetic fields needed to observe the quantum Hall effect. From this point of view, graphene is special since it allows the creation of strong pseudomagnetic fields due to strain. We show that in a Josephson junction made of strained graphene, Cooper pairs will diffuse into the strained region. The pair correlation function will be sublattice polarized due to the polarization of the local density of states in the zero pseudo-Landau level. We uncover two regimes: (1) one in which the cyclotron radius is larger than the junction length, in which case the supercurrent will be enhanced, and (2) the long junction regime where the supercurrent is strongly suppressed because the junction becomes an insulator. In the latter case quantized Hall states form and Andreev scattering at the normal/superconducting interface will induce edge states. Our numerical calculation has become possible due to an extension of the Chebyshev-Bogoliubovde Gennes method to computations on video cards (GPUs). |
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Place of Publication |
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Language |
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Wos |
000297766600003 |
Publication Date |
2011-12-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
27 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl) and the Euro GRAPHENE project CONGRAN. Discussions with Andrey Chaves are gratefully acknowledged. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93962 |
Serial |
3364 |
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Permanent link to this record |
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Author |
Stankovski, M.; Antonius, G.; Waroquiers, D.; Miglio, A.; Dixit, H.; Sankaran, K.; Giantomassi, M.; Gonze, X.; Côté, M.; Rignanese, G.-M. |
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Title |
G0W0 band gap of ZnO : effects of plasmon-pole models |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
24 |
Pages |
241201-241201,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Carefully converged calculations are performed for the band gap of ZnO within many-body perturbation theory (G0W0 approximation). The results obtained using four different well-established plasmon-pole models are compared with those of explicit calculations without such models (the contour-deformation approach). This comparison shows that, surprisingly, plasmon-pole models depending on the f-sum rule gives less precise results. In particular, it confirms that the band gap of ZnO is underestimated in the G0W0 approach as compared to experiment, contrary to the recent claim of Shih et al. [ Phys. Rev. Lett. 105 146401 (2010)]. |
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Place of Publication |
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Wos |
000297766600001 |
Publication Date |
2011-12-06 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
81 |
Open Access |
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Notes |
; The authors would like to thank P. Zhang, S. Louie, J. Deslippe, P. Rinke, H. Jiang, C. Friedrich, and F. Bruneval for many helpful discussions. We are also very grateful to Y. Pouillon, A. Jacques, and J.-M. Beuken for their technical aid and expertise. M.C. and G.A. would like to acknowledge the support of NSERC and FQRNT. This work was supported by the Interuniversity Attraction Poles program (P6/42)-Belgian State-Belgian Science Policy, the Flemish Science Foundation (FWO-Vl) ISIMADE project, the EU's 7th Framework programme through the ETSF I3 e-Infrastructure project (Grant Agreement No. 211956), the Communaute francaise de Belgique, through the Action de Recherche Concertee 07/ 12-003 “Nanosystemes hybrides metal-organiques”, and the FNRS through FRFC Project No. 2.4.589.09.F. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93963 |
Serial |
3533 |
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Permanent link to this record |
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Author |
Kao, K.-H.; Verhulst, A.S.; Vandenberghe, W.G.; Sorée, B.; Groeseneken, G.; De Meyer, K. |
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Title |
Direct and indirect band-to-band tunneling in germanium-based TFETs |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
IEEE transactions on electron devices |
Abbreviated Journal |
Ieee T Electron Dev |
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Volume |
59 |
Issue |
2 |
Pages |
292-301 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Germanium is a widely used material for tunnel FETs because of its small band gap and compatibility with silicon. Typically, only the indirect band gap of Ge at 0.66 eV is considered. However, direct band-to-band tunneling (BTBT) in Ge should be included in tunnel FET modeling and simulations since the energy difference between the Ge conduction band edges at the L and G valleys is only 0.14 eV at room temperature. In this paper, we theoretically calculate the parameters A and B of Kane's direct and indirect BTBT models at different tunneling directions ([100], [110], and [111]) for Si, Ge and unstrained Si1-xGex. We highlight how the direct BTBT component becomes more important as the Ge mole fraction increases. The calculation of the band-to-band generation rate in the uniform electric field limit reveals that direct tunneling always dominates over indirect tunneling in Ge. The impact of the direct transition in Ge on the performance of two realistic tunnel field-effect transistor configurations is illustrated with TCAD simulations. The influence of field-induced quantum confinement is included in the analysis based on a back-of-the-envelope calculation. |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000299430200005 |
Publication Date |
2011-12-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0018-9383;1557-9646; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.605 |
Times cited |
212 |
Open Access |
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Notes |
; Manuscript received August 5, 2011; revised October 5, 2011 and October 28, 2011; accepted October 30, 2011. Date of publication December 7, 2011; date of current version January 25, 2012. This work was supported by the Interuniversity Microelectronics Center's (IMEC) Industrial Affiliation Program. The work of W. G. Vandenberghe was supported by a Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). The review of this paper was arranged by Editor A. Schenk. ; |
Approved |
Most recent IF: 2.605; 2012 IF: 2.062 |
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Call Number |
UA @ lucian @ c:irua:97215 |
Serial |
708 |
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Permanent link to this record |
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Author |
Zarenia, M.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Energy levels of triangular and hexagonal graphene quantum dots : a comparative study between the tight-binding and Dirac equation approach |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
24 |
Pages |
245403-245403,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist. |
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Place of Publication |
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Wos |
000297767800008 |
Publication Date |
2011-12-07 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
145 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES Program EuroGRAPHENE (project CONGRAN), the Bilateral program between Flanders and Brazil, CAPES and the Brazilian Council for Research (CNPq). ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93961 |
Serial |
1040 |
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Permanent link to this record |
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Author |
Frolov, D.D.; Kotovshchikov, Y.N.; Morozov, I.V.; Boltalin, A.I.; Fedorova, A.A.; Marikutsa, A.V.; Rumyantseva, M.N.; Gaskov, A.M.; Sadovskaya, E.M.; Abakumov, A.M. |
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Title |
Oxygen exchange on nanocrystalline tin dioxide modified by palladium |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of solid state chemistry |
Abbreviated Journal |
J Solid State Chem |
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Volume |
186 |
Issue |
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Pages |
1-8 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Temperature-programmed oxygen isotopic exchange study was performed on nanocrystalline tin dioxide-based materials synthesized via sol-gel route and modified by palladium. Such materials are widely used as resistive gas sensors. The experiments were carried out in a flow-reactor up to complete isotopic substitution of oxygen. Substantial rates of isotopic exchange for SnO2 were observed from about 700 K. The distribution of isotopic molecules O-16(2). (OO)-O-16-O-18 and O-18(2) corresponds to simple dioxygen heteroexchange mechanism with single lattice oxygen atom. The modification of SnO2 by Pd introduced multiple heteroexchange mechanism with preliminary O-2 dissociation on the clusters surface. Spill-over of atomic oxygen from Pd to the surface of SnO2 and fast exchange with lattice oxygen result in more than 100% increase of apparent heteroexchange rate. The exchange on SnO2/Pd was shown to be a complex process involving partial deactivation of the catalytic centers at temperature higher than 750 K. (C) 2011 Elsevier Inc. All rights reserved. |
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Place of Publication |
London |
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Wos |
000299801400001 |
Publication Date |
2011-12-08 |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-4596; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.299 |
Times cited |
34 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.299; 2012 IF: 2.040 |
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Call Number |
UA @ lucian @ c:irua:96202 |
Serial |
2546 |
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Permanent link to this record |
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Author |
Sorée, B.; Magnus, W.; Vandenberghe, W. |
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Title |
Low-field mobility in ultrathin silicon nanowire junctionless transistors |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Applied physics letters |
Abbreviated Journal |
Appl Phys Lett |
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Volume |
99 |
Issue |
23 |
Pages |
233509-233509,3 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically investigate the phonon, surface roughness and ionized impurity limited low-field mobility of ultrathin silicon n-type nanowire junctionless transistors in the long channel approximation with wire radii ranging from 2 to 5 nm, as function of gate voltage. We show that surface roughness scattering is negligible as long as the wire radius is not too small and ionized impurity scattering is the dominant scattering mechanism. We also show that there exists an optimal radius where the ionized impurity limited mobility exhibits a maximum. |
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Corporate Author |
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Publisher |
American Institute of Physics |
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000298006100095 |
Publication Date |
2011-12-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0003-6951; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.411 |
Times cited |
20 |
Open Access |
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Notes |
; This work is supported by the EU project SQWIRE (FP7-ICT-STREP nr. 257111). William Vandenberghe gratefully acknowledges the Ph.D. stipend from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). ; |
Approved |
Most recent IF: 3.411; 2011 IF: 3.844 |
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Call Number |
UA @ lucian @ c:irua:92865 |
Serial |
1850 |
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Permanent link to this record |
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Author |
Abreu, Y.; Cruz, C.M.; van Espen, P.; Pérez, C.; Piñera, I.; Leyva, A.; Cabal, A.E. |
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Title |
Electric field gradient calculations in ZnO samples implanted with 111In(111Cd) |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Solid state communications |
Abbreviated Journal |
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Volume |
152 |
Issue |
5 |
Pages |
399-402 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
A first-principles study of the electric field gradient (EFG) calculated for ideal and In-111(Cd-111) implanted ZnO samples is reported in the present work. The study was made for ZnO ideal hexagonal structures and supercells were introduced in order to consider the possible implantation environments. The calculation was done using the “WIEN2k” code within the density functional theory, the exchange and correlation effects were determined by the GGA approximation. Three possible In-111(Cd-111) implantation configurations were studied, one substitutional incorporation at cation site and two interstitials. The obtained EFG values for the ideal structure and the substitutional site are in good agreement with the experimental reports measured by perturbed angular correlation (PAC) and high precision nuclear magnetic resonance (NMR). Thus, the ascription of substitutional incorporation of In-111(Cd-111) probe atom at the ZnO cation site after annealing was confirmed. (C) 2011 Elsevier Ltd. All rights reserved. |
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Wos |
000301329200016 |
Publication Date |
2011-12-09 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0038-1098 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:97821 |
Serial |
7857 |
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Permanent link to this record |
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Author |
Berger, J.; Milošević, M.V. |
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Title |
Fluctuations in superconducting rings with two order parameters |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
21 |
Pages |
214515-214515,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Motivated by two-band superconductivity in, e.g., borides and pnictides, starting from the two-band Ginzburg-Landau energy functional, we discuss how the presence of two order parameters and the coupling between them influence a superconducting ring in the fluctuative regime. Our method is an extension of the von OppenRiedel formalism for rings; it is exact, but requires numerical implementation. We also study approximations for which analytic expressions can be obtained, and check their ranges of validity. We provide estimates for the temperature ranges where fluctuations are important, calculate the persistent current in MgB2 rings as a function of temperature and enclosed flux, and point out its additional dependence on the cross-section area of the wire from which the ring is made. We find temperature regions in which fluctuations enhance the persistent currents and regions where they inhibit the persistent current. The presence of two order parameters that can fluctuate independently always leads to larger averages of the order parameters at Tc, but yields larger persistent current only for appropriate parameters. In cases of very different material parameters for the two coupled condensates, the persistent current is inhibited. |
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Place of Publication |
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Language |
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Wos |
000297932500004 |
Publication Date |
2011-12-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
7 |
Open Access |
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Notes |
; This research was supported by the Israel Science Foundation, Grant No. 249/10, the Flemish Science Foundation (FWO-Vl), and the ESF network INSTANS. We are grateful to Andrei Varlamov and Felix von Oppen for their answers to our enquiries. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:93957 |
Serial |
1226 |
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Permanent link to this record |
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Author |
Zhang, Y.-R.; Xu, X.; Bogaerts, A.; Wang, Y.-N. |
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Title |
Fluid simulation of the phase-shift effect in hydrogen capacitively coupled plasmas: 1 : transient behaviour of electrodynamics and power deposition |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
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Volume |
45 |
Issue |
1 |
Pages |
015202-015202,11 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A two-dimensional self-consistent fluid model coupled with the full set of Maxwell equations is established to investigate the phase-shift effect on the transient behaviour of electrodynamics and power deposition in a hydrogen capacitively coupled plasma. The effect has been examined at 13.56 MHz and 100 MHz, respectively, because of the different phase-shift modulation when the electromagnetic effects are dominant. The results indicate that the spatiotemporal distributions of the plasma characteristics obtained for various phase-shift cases are obviously different both in shape and especially in absolute values. Indeed, when the phase difference varies from 0 to π, there is an increase in the electron flux, thus the power deposition becomes more pronounced. At the frequency of 13.56 MHz, the axial electron flux in the bulk plasma becomes uniform along the z-axis, and the radial electron flux exhibits two peaks within one period at the reverse-phase case, whereas the oscillation is less pronounced at the in-phase case. Furthermore, in the very high frequency discharge, the radial electron flux is alternately positive and negative with four peaks during one period, and the ionization mainly occurs in the sheath region, due to the prominent power deposition there at a phase difference equal to π. |
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Corporate Author |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000298290000011 |
Publication Date |
2011-12-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3727;1361-6463; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.588 |
Times cited |
57 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.588; 2012 IF: 2.528 |
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Call Number |
UA @ lucian @ c:irua:92851 |
Serial |
1230 |
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Permanent link to this record |
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Author |
Zhang, Y.-R.; Xu, X.; Bogaerts, A.; Wang, Y.-N. |
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Title |
Fluid simulation of the phase-shift effect in hydrogen capacitively coupled plasmas: 2 : radial uniformity of the plasma characteristics |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Journal of physics: D: applied physics |
Abbreviated Journal |
J Phys D Appl Phys |
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Volume |
45 |
Issue |
1 |
Pages |
015203-015203,13 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A two-dimensional fluid model, including the full set of Maxwell equations, has been developed and applied to investigate the effect of a phase shift between two power sources on the radial uniformity of several plasma characteristics in a hydrogen capacitively coupled plasma. This study was carried out at various frequencies in the range 13.56200 MHz. When the frequency is low, at 13.56 MHz, the plasma density is characterized by an off-axis peak when both power sources are in-phase (phgr = 0), and the best radial uniformity is obtained at phgr = π. This trend can be explained because the radial nonuniformity caused by the electrostatic edge effect can be effectively suppressed by the phase-shift effect at a phase difference equal to π. When the frequency rises to 60 MHz, the plasma density profiles shift smoothly from edge-peaked over uniform to centre-peaked as the phase difference increases, due to the pronounced standing-wave effect, and the best radial uniformity is reached at phgr = 0.3π. At a frequency of 100 MHz, a similar behaviour is observed, except that the maximum of the plasma density moves again towards the radial edge at the reverse-phase case (phgr = π), because of the dominant skin effect. When the frequency is 200 MHz, the bulk plasma density increases significantly with increasing phase-shift values, and a better uniformity is obtained at phgr = 0.4π. This is because the density in the centre increases faster than at the radial edge as the phase difference rises, due to the increasing power deposition Pz in the centre and the decreasing power density Pr at the radial edge. As the phase difference increases to π, the maximum near the radial edge becomes obvious again. This is because the skin effect has a predominant influence on the plasma density under this condition, resulting in a high density at the radial edge. Moreover, the axial ion flux increases monotonically with phase difference, and exhibits similar profiles to the plasma density. The calculation results illustrate that the radial uniformity of the various plasma characteristics is strongly dependent on the applied frequency and the phase shift between both power sources, which is important to realize, for controlling the uniformity of the plasma etch and deposition processes. |
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Corporate Author |
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Publisher |
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Place of Publication |
London |
Editor |
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Language |
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Wos |
000298290000012 |
Publication Date |
2011-12-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0022-3727;1361-6463; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.588 |
Times cited |
15 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.588; 2012 IF: 2.528 |
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Call Number |
UA @ lucian @ c:irua:92852 |
Serial |
1231 |
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Permanent link to this record |
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Author |
Masir, M.R.; Matulis, A.; Peeters, F.M. |
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Title |
Scattering of Dirac electrons by circular mass barriers : valley filter and resonant scattering |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
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Volume |
84 |
Issue |
24 |
Pages |
245413-245413,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The scattering of two-dimensional (2D) massless Dirac electrons is investigated in the presence of a random array of circular mass barriers. The inverse momentum relaxation time and the Hall factor are calculated and used to obtain parallel and perpendicular resistivity components within linear transport theory. We found a nonzero perpendicular resistivity component which has opposite sign for electrons in the different K and K′ valleys. This property can be used for valley filter purposes. The total cross section for scattering on penetrable barriers exhibits resonances due to the presence of quasibound states in the barriers that show up as sharp gaps in the cross section while for Schrödinger electrons they appear as peaks. |
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Corporate Author |
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Place of Publication |
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Wos |
000297934500008 |
Publication Date |
2011-12-12 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1098-0121;1550-235X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.836 |
Times cited |
32 |
Open Access |
|
|
|
Notes |
; This work was supported by the European Science Foundation (ESF) under the EUROCORES Program Euro-GRAPHENE within the project CONGRAN. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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|
Call Number |
UA @ lucian @ c:irua:94383 |
Serial |
2951 |
|
Permanent link to this record |
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Author |
Ray, S.; Kolen'ko, Y.V.; Kovnir, K.A.; Lebedev, O.I.; Turner, S.; Chakraborty, T.; Erni, R.; Watanabe, T.; Van Tendeloo, G.; Yoshimura, M.; Itoh, M. |
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Title |
Defect controlled room temperature ferromagnetism in Co-doped barium titanate nanocrystals |
Type |
A1 Journal article |
|
Year |
2012 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
|
|
Volume |
23 |
Issue |
2 |
Pages |
025702,1-025702,10 |
|
|
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
|
|
Abstract |
Defect mediated high temperature ferromagnetism in oxide nanocrystallites is the central feature of this work. Here, we report the development of room temperature ferromagnetism in nanosized Co-doped barium titanate particles with a size of around 14 nm, synthesized by a solvothermal drying method. A combination of x-ray diffraction with state-of-the-art electron microscopy techniques confirms the intrinsic doping of Co into BaTiO3. The development of the room temperature ferromagnetism was tracked down to the different donor defects, namely hydroxyl groups at the oxygen site (\mathrm {OH}\mathrm {(O)} |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Bristol |
Editor |
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|
Language |
|
Wos |
000298409000011 |
Publication Date |
2011-12-14 |
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Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0957-4484;1361-6528; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.44 |
Times cited |
19 |
Open Access |
|
|
|
Notes |
Esteem 026019; Fwo |
Approved |
Most recent IF: 3.44; 2012 IF: 3.842 |
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Call Number |
UA @ lucian @ c:irua:93636 |
Serial |
614 |
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Permanent link to this record |
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Author |
Croitoru, M.D.; Shanenko, A.A.; Peeters, F.M.; Axt, V.M. |
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Title |
Parity-fluctuation induced enlargement of the ratio \DeltaE/kBTc in metallic grains |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
|
|
Volume |
84 |
Issue |
21 |
Pages |
214518-214518,12 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate how the interplay of quantum confinement and particle number-parity fluctuations affects superconducting correlations in ultra-small metallic grains. Using the number-parity projected BCS formalism we calculate the critical temperature and the excitation gap as a function of the grain size for grains with even and odd number of confined carriers. We show that the experimentally observed anomalous increase of the coupling ratio ΔE/kBTc with decreasing superconducting grain size can be attributed to an enhancement of the number-parity fluctuations in ultra-small grains. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000298114100003 |
Publication Date |
2011-12-16 |
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Series Editor |
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Series Title |
|
Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1098-0121;1550-235X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.836 |
Times cited |
14 |
Open Access |
|
|
|
Notes |
; This work was supported by the European Community under a Marie Curie IEF Action (Grant Agreement No. PIEF-GA-2009-235486-ScQSR), the Flamish Science Foundation (FWO-Vl), and the Belgian Science Policy (IAP). M. D. C. thanks A. S. Mel'nikov and N. B. Kopnin for fruitful discussions. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:94373 |
Serial |
2555 |
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Permanent link to this record |
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Author |
Bouvier, S.; Benmhenni, N.; Tirry, W.; Gregory, F.; Nixon, M.E.; Cazacu, O.; Rabet, L. |
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Title |
Hardening in relation with microstructure evolution of high purity \alpha-titanium deformed under monotonic and cyclic simple shear loadings at room temperature |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Materials science and engineering: part A: structural materials: properties, microstructure and processing |
Abbreviated Journal |
Mat Sci Eng A-Struct |
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Volume |
535 |
Issue |
|
Pages |
12-21 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
The aim of this paper is to gain understanding of the quasi-static, large strain deformation behavior at room-temperature of high-purity alpha-Ti with an initial split-basal texture. Simple shear tests were conducted along different directions in order to quantify the material's anisotropy and hardening evolution for different strain paths such as monotonic, Bauschinger, and cyclic loadings. The stress-strain curves indicate that the material displays strong anisotropy in the flow behavior. In order to capture the link between microstructure evolution (occurrence of twinning, grain size evolution, etc.) and the macroscopic response, a thoroughly detailed multi-scale characterization using scanning electron microscope (SEM) observations and electron backscattered diffraction (EBSD) analysis was also conducted. Specifically, EBSD analyses indicate that the twin activity and grain fragmentation are responsible for the observed difference between the macroscopic hardening rates corresponding to different directions and loading paths. (C) 2011 Elsevier B.V. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lausanne |
Editor |
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Language |
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Wos |
000301402400003 |
Publication Date |
2011-12-17 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
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|
ISSN |
0921-5093; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
3.094 |
Times cited |
22 |
Open Access |
|
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|
Notes |
|
Approved |
Most recent IF: 3.094; 2012 IF: 2.108 |
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Call Number |
UA @ lucian @ c:irua:97824 |
Serial |
1410 |
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Permanent link to this record |
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Author |
Tirumalasetty, G.K.; van Huis, M.A.; Kwakernaak, C.; Sietsma, J.; Sloof, W.G.; Zandbergen, H.W. |
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Title |
Deformation-induced austenite grain rotation and transformation in TRIP-assisted steel |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Acta materialia |
Abbreviated Journal |
Acta Mater |
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Volume |
60 |
Issue |
3 |
Pages |
1311-1321 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Uniaxial straining experiments were performed on a rolled and annealed Si-alloyed TRIP (transformation-induced plasticity) steel sheet in order to assess the role of its microstructure on the mechanical stability of austenite grains with respect to martensitic transformation. The transformation behavior of individual metastable austenite grains was studied both at the surface and inside the bulk of the material using electron back-scattered diffraction (EBSD) and X-ray diffraction (XRD) by deforming the samples to different strain levels up to about 20%. A comparison of the XRD and EBSD results revealed that the retained austenite grains at the surface have a stronger tendency to transform than the austenite grains in the bulk of the material. The deformation-induced changes of individual austenite grains before and after straining were monitored with EBSD. Three different types of austenite grains can be distinguished that have different transformation behaviors: austenite grains at the grain boundaries between ferrite grains, twinned austenite grains, and embedded austenite grains that are completely surrounded by a single ferrite grain. It was found that twinned austenite grains and the austenite grains present at the grain boundaries between larger ferrite grains typically transform first, i.e. are less stable, in contrast to austenite grains that are completely embedded in a larger ferrite grain. In the latter case, straining leads to rotations of the harder austenite grain within the softer ferrite matrix before the austenite transforms into martensite. The analysis suggests that austenite grain rotation behavior is also a significant factor contributing to enhancement of the ductility. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Oxford |
Editor |
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Language |
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Wos |
000301157900054 |
Publication Date |
2011-12-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1359-6454; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
5.301 |
Times cited |
80 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 5.301; 2012 IF: 3.941 |
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Call Number |
UA @ lucian @ c:irua:97210 |
Serial |
630 |
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Permanent link to this record |
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Author |
Tikhomirov, V.K.; Vosch, T.; Fron, E.; Rodríguez, V.D.; Velázquez, J.J.; Kirilenko, D.; Van Tendeloo, G.; Hofkens, J.; Van der Auweraer, M.; Moshchalkov, V.V. |
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Title |
Luminescence of oxyfluoride glasses co-doped with Ag nanoclusters and Yb3+ ions |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
RSC advances |
Abbreviated Journal |
Rsc Adv |
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Volume |
2 |
Issue |
4 |
Pages |
1496-1501 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Bulk oxyfluoride glasses co-doped with Ag nanoclusters and Yb3+ ions have been prepared by a melt quenching technique. When excited in the absorption band of the Ag nanoclusters between 300 to 500 nm, these glasses emit a broad band characteristic of the Ag nanoclusters between 400 to 750 nm as well as an emission band between 900 to 1100 nm, originating from Yb3+ ions. The intensity ratio of the Yb3+/Ag emission bands increases with the Ag doping level at a fixed concentration of Yb3+, indicating the presence of energy transfer mechanism from the Ag nanoclusters to the Yb3+ ions. Comparison of time-resolved decay kinetics of the luminescence in the respectively Ag nanocluster-Yb3+ co-doped and single Ag nanocluster doped glasses, hints towards an energy transfer from the red and infrared emitting Ag nanoclusters to the Yb3+ ions. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000299695300038 |
Publication Date |
2011-12-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2046-2069; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.108 |
Times cited |
46 |
Open Access |
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Notes |
Fwo; Iap |
Approved |
Most recent IF: 3.108; 2012 IF: 2.562 |
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Call Number |
UA @ lucian @ c:irua:96239 |
Serial |
1856 |
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Permanent link to this record |
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Author |
Pachoud, E.; Bréard, Y.; Martin, C.; Maignan, A.; Abakumov, A.M.; Suard, E.; Smith, R.I.; Suchomel, M.R. |
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Title |
Bi0.75Sr0.25FeO3-\delta : revealing order/disorder phenomena by combining diffraction techniques |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Solid state communications |
Abbreviated Journal |
Solid State Commun |
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Volume |
152 |
Issue |
5 |
Pages |
331-336 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The local and long range structure of polycrystalline samples of Bi0.75Sr0.25FeO3-delta has been probed by neutron and synchrotron X-ray diffraction coupled with transmission electron microscopy. It is found that the long range structure on average can be described by the cubic space group Pm-3m (a(p) congruent to 3.951 angstrom). However, the refinements revealed large atomic displacements for the (Bi, Sr) cations and the oxygen atoms from their ideal positions. The electron microscopy study indicates the existence of local phenomena like local ordering of oxygen vacancies, which are segregated at the randomly spaced parallel (FeO2-delta) planes, or the existence of region of different symmetry, probably R3c. At room temperature, the compound exhibits G-type antiferromagnetism (T-N congruent to 650 K) with a magnetic moment of congruent to 3.7 mu(B). (C) 2012 Elsevier Ltd. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000301329200001 |
Publication Date |
2011-12-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
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Edition |
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ISSN |
0038-1098; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.554 |
Times cited |
6 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 1.554; 2012 IF: 1.534 |
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Call Number |
UA @ lucian @ c:irua:97820 |
Serial |
3516 |
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Permanent link to this record |
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Author |
Margui, E.; Hidalgo, M.; Queralt, I.; van Meel, K.; Fontas, C. |
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Title |
Analytical capabilities of laboratory, benchtop and handheld X-ray fluorescence systems for detection of metals in aqueous samples pre-concentrated with solid-phase extraction disks |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Spectrochimica acta: part B : atomic spectroscopy |
Abbreviated Journal |
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Volume |
67 |
Issue |
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Pages |
17-23 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
We aimed to achieve improved instrumental sensitivity and detection limits for the analysis of several elements (Cu, Ni, Zn, Pb and Cd) in aqueous samples with energy dispersive X-ray fluorescence spectrometry (EDXRF). The metals were pre-concentrated from aqueous solutions using commercially available organic-based solid-phase extraction (SPE) disks functionalized with iminodiacetate groups. These thin-layer organic materials provide an ideal support for XRF analysis. The elements were collected on the SPE extraction disks using a simple filtration procedure (starting with 1 L of aqueous sample) that allows direct XRF measurements to be performed in the field (in situ). We evaluated the analytical possibilities and drawbacks of using this pre-concentration procedure in combination with the following XRF configurations: a handheld unit, a benchtop EDXRF system and a high-energy polarized-beam EDXRF instrument (HE-P-EDXRF). Using the HE-P-EDXRF system, the detection limits for all metals were more than one order of magnitude lower than those attained using handheld and benchtop EDXRF instrumentation. For the detection of metal concentrations higher than similar to 20 mu g/L, however, handheld or benchtop systems remain a very good option due to their extreme simplicity of operation and low-cost, compact design. We demonstrate the application of these methodologies, using the three equipment systems, to the analysis of trace concentrations of metals in different types of aqueous samples, including tap water and waste water. (C) 2011 Elsevier B.V. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000302757200003 |
Publication Date |
2011-12-19 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0584-8547; 1873-3565 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
|
Times cited |
|
Open Access |
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Notes |
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Approved |
no |
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Call Number |
UA @ admin @ c:irua:98338 |
Serial |
7454 |
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Permanent link to this record |
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Author |
De Backer, L.A.; Vos, W.; de Backer, J.; Van Holsbeke, C.; Vinchurkar, S.; de Backer, W. |
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Title |
The acute effect of budesonide/formoterol in COPD : a multi-slice computed tomography and lung function study |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
European Respiratory Journal |
Abbreviated Journal |
Eur Respir J |
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Volume |
40 |
Issue |
2 |
Pages |
298-305 |
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Keywords |
A1 Journal article; Biophysics and Biomedical Physics; Condensed Matter Theory (CMT); Laboratory Experimental Medicine and Pediatrics (LEMP) |
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Abstract |
The Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification of chronic obstructive pulmonary disease (COPD) does not always match with other clinical disease descriptors such as exacerbation frequency and quality of life, indicating that forced expiratory volume in 1 s (FEV1) is not a perfect descriptor of the disease. The aim of this study was to find out whether changes in airway geometry after inhalation of the most commonly used inhalation therapy in severe COPD can more adequately be described with an image-based approach than with spirometry. 10 COPD GOLD stage III patients were assessed in a double-blind crossover study. Airway volumes were analysed using segmentation of multi-slice computed tomography (MSCT) images; airway resistance was determined using computational fluid dynamics (CFD). Distal airway volume significantly increased (p=0.011) in patients 4 h after receiving a budesonide/formoterol combination from 9.6+/-4.67 cm(3) to 10.14+/-4.81 cm(3). Also CFD-determined airway resistance significantly decreased (p=0.047) from 0.051+/-0.021 kPa.s.L-1 to 0.043+/- 0.019 kPa.s.L-1. None of the lung function parameters showed a significant change. Only functional residual capacity (FRC) showed a trend to decline (p=0.056). Only the image-based parameters were able to predict the visit at which the combination product was administered. This study showed that imaging is a sensitive, complementary tool to describe changes in airway structure. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Copenhagen |
Editor |
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Language |
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Wos |
000307291700006 |
Publication Date |
2011-12-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0903-1936;1399-3003; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
10.569 |
Times cited |
37 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 10.569; 2012 IF: 6.355 |
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Call Number |
UA @ lucian @ c:irua:101113 |
Serial |
3568 |
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Permanent link to this record |
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Author |
Witters, N.; Mendelsohn, R.; Van Passel, S.; Van Slycken, S.; Weyens, N.; Schreurs, E.; Meers, E.; Tack, F.; Vanheusden, B.; Vangronsveld, J. |
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Title |
Phytoremediation, a sustainable remediation technology? 2 : economic assessment of CO2 abatement through the use of phytoremediation crops for renewable energy production |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Biomass & Bioenergy |
Abbreviated Journal |
Biomass Bioenerg |
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Volume |
39 |
Issue |
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Pages |
470-477 |
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Keywords |
A1 Journal article; Economics; Engineering Management (ENM) |
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Abstract |
Phytoremediation could be a sustainable remediation alternative for conventional remediation technologies. However, its implementation on a commercial scale remains disappointing. To emphasize its sustainability, this paper examines whether and how the potential economic benefit of CO2 abatement for different crops used for phytoremediation or sustainable land management purposes could promote phytotechnologies. Our analysis is based on a case study in the Campine region, where agricultural soils are contaminated with mainly cadmium. We use Life Cycle Analysis to show for the most relevant crops (willow (Salix spp), energy maize (Zea mays), and rapeseed (Brassica napus)), that phytoremediation, used for renewable energy production, could abate CO2. Converting this in economic numbers through the Marginal Abatement Cost of CO2 ( 20 ton−1) we can integrate this in the economic analysis to compare phytoremediation crops among each other, and phytoremediation with conventional technologies. The external benefit of CO2 abatement when using phytoremediation crops for land management ranges between 55 and 501 per hectare. The purpose of these calculations is not to calculate a subsidy for phytoremediation. There is no reason why one would prefer phytoremediation crops for renewable energy production over normal biomass. Moreover, subsidies for renewable energy already exist. Therefore, we should not integrate these numbers in the economic analysis again. However, these numbers could contribute to making explicit the competitive advantage of phytoremediation compared to conventional remediation technologies, but also add to a more sustainably funded decision on which crop should be grown on contaminated land. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
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Editor |
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Language |
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Wos |
000302829900054 |
Publication Date |
2011-12-20 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0961-9534 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.219 |
Times cited |
38 |
Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 3.219; 2012 IF: 2.975 |
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Call Number |
UA @ admin @ c:irua:129863 |
Serial |
6236 |
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Permanent link to this record |
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Author |
Coghe, F.; Tirry, W.; Rabet, L.; Schryvers, D.; Van Houtte, P. |
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Title |
Importance of twinning in static and dynamic compression of a Ti-6Al-4V titanium alloy with an equiaxed microstructure |
Type |
A1 Journal article |
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Year |
2012 |
Publication |
Materials science and engineering: part A: structural materials: properties, microstructure and processing |
Abbreviated Journal |
Mat Sci Eng A-Struct |
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Volume |
537 |
Issue |
|
Pages |
1-10 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
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Abstract |
Whereas deformation twinning is known to be an important deformation mechanism for hexagonal materials like magnesium and pure titanium, so far almost no literature exists on the twinning behaviour of the Ti-6Al-4V alloy. In this work it was shown that the activation of twinning as a deformation mechanism could have a pronounced effect on the mechanical behaviour of the Ti-6Al-4V alloy. This effect is even more pronounced under dynamic loading conditions. Transmission electron microscopy showed that only the {1 0 1 2}{1 0 1 1} tensile twin system was activated under certain loading conditions. Light-optical microscopy and electron backscatter diffraction data were afterwards used to experimentally determine the twin fractions. The importance of twinning for the texture evolution was also studied. It was shown that even small twin fractions can lead to distinct texture features, especially due to the discrete reorientation of the c-axes. The experimental results were compared to simulated results that were obtained with a viscoplastic self-consistent crystal plasticity code, after experimental validation that twinning can be reliably modelled as a unidirectional slip system. Although good agreement was obtained for the experimental and simulated stress-strain curves, the simulated results concerning twinning correlated well only on a qualitative basis as the simulated twin fractions were systematically higher than the experimental fractions. This seems to strengthen the hypothesis made by other research groups that complete grains might reorient by twinning. (C) 2011 Elsevier B.V. All rights reserved. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lausanne |
Editor |
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Language |
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Wos |
000301473300001 |
Publication Date |
2011-12-21 |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0921-5093; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.094 |
Times cited |
35 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.094; 2012 IF: 2.108 |
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Call Number |
UA @ lucian @ c:irua:97818 |
Serial |
1565 |
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Permanent link to this record |