Records |
Author |
Leenaerts, O.; Vercauteren, S.; Schoeters, B.; Partoens, B. |
Title |
System-size dependent band alignment in lateral two-dimensional heterostructures |
Type |
A1 Journal article |
Year |
2016 |
Publication |
2D materials |
Abbreviated Journal |
2D Mater |
Volume |
3 |
Issue |
3 |
Pages |
025012 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The electronic band alignment in semiconductor heterostructures is a key factor for their use in electronic applications. The alignment problem has been intensively studied for bulk systems but is less well understood for low-dimensional heterostructures. In this work we investigate the alignment in two-dimensional lateral heterostructures. First-principles calculations are used to show that the electronic band offset depends crucially on the width and thickness of the heterostructure slab. The particular heterostructures under study consist of thin hydrogenated and fluorinated diamond slabs which are laterally joined together. Two different limits for the band offset are observed. For infinitely wide heterostructures the vacuum potential above the two materials is aligned leading to a large step potential within the heterostructure. For infinitely thick heterostructure slabs, on the other hand, there is no potential step in the heterostructure bulk, but a large potential step in the vacuum region above the heterojunction is observed. The band alignment in finite systems depends on the particular dimensions of the system. These observations are shown to result from an interface dipole at the heterojunction that tends to align the band structures. |
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 |
000378571400032 |
Publication Date |
2016-04-13 |
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 |
2053-1583 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.937 |
Times cited |
19 |
Open Access |
|
Notes |
This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government— department EWI. |
Approved |
Most recent IF: 6.937 |
Call Number |
c:irua:132792 c:irua:132792 |
Serial |
4055 |
Permanent link to this record |
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Author |
Schoeters, B.; Leenaerts, O.; Pourtois, G.; Partoens, B. |
Title |
Ab-initio study of the segregation and electronic properties of neutral and charged B and P dopants in Si and Si/SiO2 nanowires |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Journal of applied physics |
Abbreviated Journal |
J Appl Phys |
Volume |
118 |
Issue |
118 |
Pages |
104306 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
We perform first-principles calculations to investigate the preferred positions of B and P dopants, both neutral and in their preferred charge state, in Si and Si/SiO2 core-shell nanowires (NWs). In order to understand the observed trends in the formation energy, we isolate the different effects that determine these formation energies. By making the distinction between the unrelaxed and the relaxed formation energy, we separate the impact of the relaxation from that of the chemical environment. The unrelaxed formation energies are determined by three effects: (i) the effect of strain caused by size mismatch between the dopant and the host atoms, (ii) the local position of the band edges, and (iii) a screening effect. In the case of the SiNW (Si/SiO2 NW), these effects result in an increase of the formation energy away from the center (interface). The effect of relaxation depends on the relative size mismatch between the dopant and host atoms. A large size mismatch causes substantial relaxation that reduces the formation energy considerably, with the relaxation being more pronounced towards the edge of the wires. These effects explain the surface segregation of the B dopants in a SiNW, since the atomic relaxation induces a continuous drop of the formation energy towards the edge. However, for the P dopants, the formation energy starts to rise when moving from the center but drops to a minimum just next to the surface, indicating a different type of behavior. It also explains that the preferential location for B dopants in Si/SiO2 core-shell NWs is inside the oxide shell just next to the interface, whereas the P dopants prefer the positions next to the interface inside the Si core, which is in agreement with recent experiments. These preferred locations have an important impact on the electronic properties of these core-shell NWs. Our simulations indicate the possibility of hole gas formation when B segregates into the oxide shell. |
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 |
000361636900031 |
Publication Date |
2015-09-09 |
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 |
|
ISSN |
0021-8979 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.068 |
Times cited |
3 |
Open Access |
|
Notes |
This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish government and the Universiteit Antwerpen. |
Approved |
Most recent IF: 2.068; 2015 IF: 2.183 |
Call Number |
c:irua:128729 |
Serial |
4056 |
Permanent link to this record |
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Author |
Leenaerts, O.; Schoeters, B.; Partoens, B. |
Title |
Stable kagome lattices from group IV elements |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
91 |
Issue |
91 |
Pages |
115202 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
A thorough investigation of three-dimensional kagome lattices of group IV elements is performed with first-principles calculations. The investigated kagome lattices of silicon and germanium are found to be of similar stability as the recently proposed carbon kagome lattice. Carbon and silicon kagome lattices are both direct-gap semiconductors but they have qualitatively different electronic band structures. While direct optical transitions between the valence and conduction bands are allowed in the carbon case, no such transitions can be observed for silicon. The kagome lattice of germanium exhibits semimetallic behavior but can be transformed into a semiconductor after compression. |
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 |
000351900700003 |
Publication Date |
2015-03-10 |
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 |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
12 |
Open Access |
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Notes |
; This work was supported by the Fonds Wetenschappelijk Onderzoek (FWO-Vl). The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Hercules Foundation and the Flemish Government – department EWI. ; |
Approved |
Most recent IF: 3.836; 2015 IF: 3.736 |
Call Number |
c:irua:125516 |
Serial |
3144 |
Permanent link to this record |
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Author |
Schoeters, B.; Neyts, E.C.; Khalilov, U.; Pourtois, G.; Partoens, B. |
Title |
Stability of Si epoxide defects in Si nanowires : a mixed reactive force field/DFT study |
Type |
A1 Journal article |
Year |
2013 |
Publication |
Physical chemistry, chemical physics |
Abbreviated Journal |
Phys Chem Chem Phys |
Volume |
15 |
Issue |
36 |
Pages |
15091-15097 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT); Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
Abstract |
Modeling the oxidation process of silicon nanowires through reactive force field based molecular dynamics simulations suggests that the formation of Si epoxide defects occurs both at the Si/SiOx interface and at the nanowire surface, whereas for flat surfaces, this defect is experimentally observed to occur only at the interface as a result of stress. In this paper, we argue that the increasing curvature stabilizes the defect at the nanowire surface, as suggested by our density functional theory calculations. The latter can have important consequences for the opto-electronic properties of thin silicon nanowires, since the epoxide induces an electronic state within the band gap. Removing the epoxide defect by hydrogenation is expected to be possible but becomes increasingly difficult with a reduction of the diameter of the nanowires. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000323520600029 |
Publication Date |
2013-07-16 |
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 |
1463-9076;1463-9084; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
4.123 |
Times cited |
3 |
Open Access |
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Notes |
; BS gratefully acknowledges financial support of the IWT, Institute for the Promotion of Innovation by Science and Technology in Flanders, via the SBO project “SilaSol”. This work was carried out using the Turing HPC infrastructure at the CalcUA core facility of the Universiteit Antwerpen, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish government and the Universiteit Antwerpen. ; |
Approved |
Most recent IF: 4.123; 2013 IF: 4.198 |
Call Number |
UA @ lucian @ c:irua:110793 |
Serial |
3130 |
Permanent link to this record |
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Author |
Bals, S.; Van Aert, S.; Romero, C.P.; Lauwaet, K.; Van Bael, M.J.; Schoeters, B.; Partoens, B.; Yuecelen, E.; Lievens, P.; Van Tendeloo, G. |
Title |
Atomic scale dynamics of ultrasmall germanium clusters |
Type |
A1 Journal article |
Year |
2012 |
Publication |
Nature communications |
Abbreviated Journal |
Nat Commun |
Volume |
3 |
Issue |
897 |
Pages |
897 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT); Condensed Matter Theory (CMT) |
Abstract |
Starting from the gas phase, small clusters can be produced and deposited with huge flexibility with regard to composition, materials choice and cluster size. Despite many advances in experimental characterization, a detailed morphology of such clusters is still lacking. Here we present an atomic scale observation as well as the dynamical behaviour of ultrasmall germanium clusters. Using quantitative scanning transmission electron microscopy in combination with ab initio calculations, we are able to characterize the transition between different equilibrium geometries of a germanium cluster consisting of less than 25 atoms. Seven-membered rings, trigonal prisms and some smaller subunits are identified as possible building blocks that stabilize the structure. |
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 |
000306099900024 |
Publication Date |
2012-06-12 |
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 |
2041-1723; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
12.124 |
Times cited |
90 |
Open Access |
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Notes |
Fwo; Iap; Iwt |
Approved |
Most recent IF: 12.124; 2012 IF: 10.015 |
Call Number |
UA @ lucian @ c:irua:100340 |
Serial |
183 |
Permanent link to this record |
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Author |
Cambré, S.; Schoeters, B.; Luyckx, S.; Goovaerts, E.; Wenseleers, W. |
Title |
Experimental observation of single-file water filling of thin single-wall carbon nanotubes down to chiral index (5,3) |
Type |
A1 Journal article |
Year |
2010 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
104 |
Issue |
20 |
Pages |
207401,1-207401,4 |
Keywords |
A1 Journal article; Particle Physics Group; Nanostructured and organic optical and electronic materials (NANOrOPT); Condensed Matter Theory (CMT) |
Abstract |
Single-file transport of water into carbon nanotubes is experimentally demonstrated for the first time through the splitting of the radial breathing mode (RBM) vibration in Raman spectra of bile salt solubilized tubes when both empty (closed) and water-filled (open-ended) tubes are present. D2O filling is observed for a wide range of diameters, d, down to very thin tubes [e.g., (5,3) tube, d=0.548 nm] for which only a single water molecule fits in the cross section of the internal nanotube channel. The shift in RBM frequency upon filling is found to display a very complex dependence on nanotube diameter and chirality, in support of a different yet well-defined ordering and orientation of water molecules at room temperature. Large shifts of the electronic transitions are also observed. |
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 |
000277945900051 |
Publication Date |
2010-05-17 |
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 |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
140 |
Open Access |
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Notes |
; Financial support from the Fund for Scientific Research Flanders, Belgium (FWO-Vlaanderen) (Project No. G.0129.07), is gratefully acknowledged. ; |
Approved |
Most recent IF: 8.462; 2010 IF: 7.622 |
Call Number |
UA @ lucian @ c:irua:83383 |
Serial |
1141 |
Permanent link to this record |
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Author |
Schoeters, B. |
Title |
An ab initio study of the properties of doped semiconducting nanwires |
Type |
Doctoral thesis |
Year |
2015 |
Publication |
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Abbreviated Journal |
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Volume |
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Issue |
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Pages |
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Keywords |
Doctoral thesis; Condensed Matter Theory (CMT) |
Abstract |
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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 |
Antwerpen |
Editor |
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Language |
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Wos |
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Publication Date |
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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 |
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ISBN |
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Additional Links |
UA library record |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:128354 |
Serial |
4133 |
Permanent link to this record |