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Author |
Varley, J.B.; Peelaers, H.; Janotti, A.; van de Walle, C.G. |
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Title |
Hydrogenated cation vacancies in semiconducting oxides |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
23 |
Issue |
33 |
Pages |
334212,1-334212,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using first-principles calculations we have studied the electronic and structural properties of cation vacancies and their complexes with hydrogen impurities in SnO2, In2O3 and β-Ga2O3. We find that cation vacancies have high formation energies in SnO2 and In2O3 even in the most favorable conditions. Their formation energies are significantly lower in β-Ga2O3. Cation vacancies, which are compensating acceptors, strongly interact with H impurities resulting in complexes with low formation energies and large binding energies, stable up to temperatures over 730 °C. Our results indicate that hydrogen has beneficial effects on the conductivity of transparent conducting oxides: it increases the carrier concentration by acting as a donor in the form of isolated interstitials, and by passivating compensating acceptors such as cation vacancies; in addition, it potentially enhances carrier mobility by reducing the charge of negatively charged scattering centers. We have also computed vibrational frequencies associated with the isolated and complexed hydrogen, to aid in the microscopic identification of centers observed by vibrational spectroscopy. |
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Place of Publication |
London |
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Wos |
000294060600014 |
Publication Date |
2011-08-04 |
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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 |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.649 |
Times cited |
125 |
Open Access |
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Notes |
; We gratefully acknowledge useful discussions with M D Mc-Cluskey, O Bierwagen and J Speck. The work was supported by the NSF MRSEC Program (DMR05-20415), the Flemish Science Foundation (FWO-VI), the Belgian American Educational Foundation, and by Saint-Gobain Research, and made use of computing facilities at CNSI (NSF grant No. CHE-0321368), TeraGrid and TACC (NSF grant No. DMR070072N), and NERSC (DOE Office of Science Contract No. DE-AC02-05CH11231). ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
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Call Number |
UA @ lucian @ c:irua:92415 |
Serial |
1534 |
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Permanent link to this record |
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Author |
Hao, Y.L.; Djotyan, A.P.; Avetisyan, A.A.; Peeters, F.M. |
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Title |
D- shallow donor near a semiconductor-metal and a semiconductor-dielectric interface |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
23 |
Issue |
11 |
Pages |
115303,1-115313,9 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The ground state energy and the extent of the wavefunction of a negatively charged donor (D − ) located near a semiconductormetal or a semiconductordielectric interface are obtained. We apply the effective mass approximation and use a variational two-electron wavefunction that takes into account the influence of all image charges that arise due to the presence of the interface, as well as the correlation between the two electrons bound to the donor. For a semiconductormetal interface, the D − binding energy is enhanced for donor positions d > 1.5aB (aB is the effective Bohr radius) due to the additional attraction of the electrons with their images. When the donor approaches the interface (i.e. d < 1.5aB) the D − binding energy drops and eventually it becomes unbound. For a semiconductordielectric (or a semiconductorvacuum) interface the D − binding energy is reduced for any donor position as compared to the bulk case and the system becomes rapidly unbound when the donor approaches the interface. |
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Place of Publication |
London |
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Wos |
000287969200013 |
Publication Date |
2011-03-04 |
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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 |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.649 |
Times cited |
5 |
Open Access |
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Notes |
; This work was supported by the Belgian Science Policy (IAP) and the Brazilian Science Foundation CNPq. One of us (AAA) was supported by a fellowship from the Belgian Federal Science Policy Office (IAP). ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
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Call Number |
UA @ lucian @ c:irua:88828 |
Serial |
3528 |
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Permanent link to this record |
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Author |
Rakhimov, K.Y.; Chaves, A.; Farias, G.A.; Peeters, F.M. |
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Title |
Wavepacket scattering of Dirac and Schrödinger particles on potential and magnetic barriers |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
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Volume |
23 |
Issue |
27 |
Pages |
275801,1-275801,16 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We investigate the dynamics of a charged particle moving in a graphene layer and in a two-dimensional electron gas, where it obeys the Dirac and the Schrödinger equations, respectively. The charge carriers are described as Gaussian wavepackets. The dynamics of the wavepackets is studied numerically by solving both quantum-mechanical and relativistic equations of motion. The scattering of such wavepackets by step-like magnetic and potential barriers is analysed for different values of wavepacket energy and width. We find: (1) that the average position of the wavepacket does not coincide with the classical trajectory, and (2) that, for slanted incidence, the path of the centre of mass of the wavepacket does not have to penetrate the barrier during the scattering process. Trembling motion of the charged particle in graphene is observed in the absence of an external magnetic field and can be enhanced by a substrate-induced mass term. |
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Corporate Author |
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Place of Publication |
London |
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Language |
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Wos |
000291993600009 |
Publication Date |
2011-06-18 |
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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 |
0953-8984;1361-648X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.649 |
Times cited |
32 |
Open Access |
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Notes |
; Discussions with A Matulis are gratefully acknowledged. KR is beneficiary of a mobility grant from the Belgian Federal Science Policy Office, co-funded by the European Commission and was supported in part by a grant of the Third World Academy of Sciences (ref. 09-188 RG/PHYS/AS-I). In addition, this work was financially supported by CNPq, under contract NanoBioEstruturas 555183/2005-0, PRONEX/FUNCAP, CAPES, the Bilateral programme between Flanders and Brazil, the joint project CNPq-FWO, the Belgian Science Policy (IAP) and the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 2.649; 2011 IF: 2.546 |
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Call Number |
UA @ lucian @ c:irua:90880 |
Serial |
3908 |
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Permanent link to this record |
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Author |
Zhang, L.; Vleugels, J.; Darchuk, L.; van der Biest, O. |
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Title |
Magnetic field oriented tetragonal zirconia with anisotropic toughness |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of the European Ceramic Society |
Abbreviated Journal |
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Volume |
31 |
Issue |
8 |
Pages |
1405-1412 |
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Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
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Abstract |
(0 0 1)-oriented 3 mol% yttria stabilized tetragonal zirconia (3Y-TZP) has been developed by reactive synthesis of undoped pure monoclinic zirconia and co-precipitated 8 mol% yttria-stabilized zirconia (8Y-ZrO2). The dispersed pure monoclinic ZrO2 powder, having magnetic anisotropy, was first aligned in a strong magnetic field and co-sintered in a randomly distributed cubic 8Y-ZrO2 fine matrix powder. The reactive sintering resulted in a 3Y-TZP ceramic with a (0 0 1) orientation. The (0 0 1)-oriented 3Y-TZP showed a substantial toughness anisotropy, i.e. the toughness along the [0 0 1] direction is 54% higher than that of its perpendicular direction. Moreover, the toughness along the [0 0 1] direction is 49% higher than that of a non-textured isotropic reactively synthesized 3Y-TZP and 110% higher than that of an isotropic co-precipitated powder based 3Y-TZP. The substantially enhanced toughness was interpreted in terms of the tetragonal to monoclinic martensitic phase transformability. |
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Corporate Author |
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Place of Publication |
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Wos |
000290189100008 |
Publication Date |
2011-03-08 |
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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 |
0955-2219 |
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:89722 |
Serial |
8192 |
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Permanent link to this record |
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Author |
Canioni, R.; Roch-Marchal, C.; Sécheresse, F.; Horcajada, P.; Serre, C.; Hardi-Dan, M.; Férey, G.; Grenèche, J.-M.; Lefebvre, F.; Chang, J.-S.; Hwang, Y.-K.; Lebedev, O.; Turner, S.; Van Tendeloo, G. |
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Title |
Stable polyoxometalate insertion within the mesoporous metal organic framework MIL-100(Fe) |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
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Volume |
21 |
Issue |
4 |
Pages |
1226-1233 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Successful encapsulation of polyoxometalate (POM) within the framework of a mesoporous iron trimesate MIL-100(Fe) sample has been achieved by direct hydrothermal synthesis in the absence of fluorine. XRPD, 31P MAS NMR, IR, EELS, TEM and 57Fe Mössbauer spectrometry corroborate the insertion of POM within the cavities of the MOF. The experimental Mo/Fe ratio is 0.95, in agreement with the maximum theoretical amount of POM loaded within the pores of MIL-100(Fe), based on steric hindrance considerations. The POM-MIL-100(Fe) sample exhibits a pore volume of 0.373 cm3 g−1 and a BET surface area close to 1000 m2 g−1, indicating that small gas molecules can easily diffuse inside the cavities despite the presence of heavy phosphomolybdates. These latter contribute to the decrease in the overall surface area, due to the increase in molar weight, by 65%. Moreover, the resulting Keggin containing MIL-100(Fe) solid is stable in aqueous solution with no POM leaching even after more than 2 months. In addition, no exchange of the Keggin anions by tetrabutylammonium perchlorate in organic media has been observed. |
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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 |
000286110400042 |
Publication Date |
2010-11-25 |
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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 |
0959-9428;1364-5501; |
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 |
158 |
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:88642 |
Serial |
3145 |
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Permanent link to this record |
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Author |
Yang, T.; Perkisas, T.; Hadermann, J.; Croft, M.; Ignatov, A.; Van Tendeloo, G.; Greenblatt, M. |
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Title |
Synthesis and structure determination of ferromagnetic semiconductors LaAMnSnO6(A = Sr, Ba) |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
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Volume |
21 |
Issue |
1 |
Pages |
199-205 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
LaAMnSnO(6) (A = Sr, Ba) have been synthesized by high temperature solid-state reactions under dynamic 1% H(2)/Ar flow. Rietveld refinements on room temperature powder X-ray diffraction data indicate that LaSrMnSnO(6) crystallizes in the GdFeO(3)-structure, with space group Pnma and, combined with transmission electron microscopy, LaBaMnSnO(6) in Imma. Both space groups are common in disordered double-perovskites. The Mn(3+) and Sn(4+) ions whose valence states were confirmed by X-ray absorption spectroscopy, are completely disordered over the B-sites and the BO(6) octahedra are slightly distorted. LaAMnSnO(6) are ferromagnetic semiconductors with a T(C) = 83 K for the Sr- and 66 K for the Ba-compound. The title compounds, together with the previously reported LaCaMnSnO(6) provide an interesting example of progression from Pnma to Imma as the tolerance factor increases. An analysis of the relationship between space group and tolerance factor for the series LaAMnMO(6) (A = Ca, Sr, Ba; M = Sn, Ru) provides a better understanding of the symmetry determination for double perovskites. |
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Corporate Author |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000285067300025 |
Publication Date |
2010-10-26 |
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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 |
0959-9428;1364-5501; |
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 |
3 |
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:95527 |
Serial |
3440 |
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Permanent link to this record |
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Author |
Grodzinska, D.; Pietra, F.; van Huis, M.A.; Vanmaekelbergh, D.; de Mello Donegá, C. |
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Title |
Thermally induced atomic reconstruction of PbSe/CdSe core/shell quantum dots into PbSe/CdSe bi-hemisphere hetero-nanocrystals |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
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Volume |
21 |
Issue |
31 |
Pages |
11556-11565 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The properties of hetero-nanocrystals (HNCs) depend strongly on the mutual arrangement of the nanoscale components. In this work we have investigated the structural and morphological evolution of colloidal PbSe/CdSe core/shell quantum dots upon annealing under vacuum. Prior to annealing the PbSe core has an approximately octahedral morphology with eight {111} facets, and the CdSe shell has zinc-blende crystal structure. Thermal annealing under vacuum at temperatures between 150 °C and 200 °C induces a structural and morphological reconstruction of the HNCs whereby the PbSe core and the CdSe shell are reorganized into two hemispheres joined by a common {111} Se plane. This thermally induced reconstruction leads to considerable changes in the optical properties of the colloidal PbSe/CdSe HNCs. |
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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 |
000293190200018 |
Publication Date |
2011-04-21 |
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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 |
0959-9428;1364-5501; |
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 |
44 |
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:91945 |
Serial |
3632 |
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Permanent link to this record |
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Author |
Esken, D.; Noei, H.; Wang, Y.; Wiktor, C.; Turner, S.; Van Tendeloo, G.; Fischer, R.A. |
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Title |
ZnO@ZIF-8 : stabilization of quantum confined ZnO nanoparticles by a zinc methylimidazolate framework and their surface structural characterization probed by CO2 adsorption |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of materials chemistry |
Abbreviated Journal |
J Mater Chem |
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Volume |
21 |
Issue |
16 |
Pages |
5907-5915 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The microporous and activated zeolitic imidazolate framework (Zn(MeIM)2; MeIM = imidazolate-2-methyl; ZIF-8) was loaded with the MOCVD precursor diethyl zinc [Zn(C2H5)2]. Exposure of ZIF-8 to the vapour of the volatile organometallic molecule resulted in the formation of the inclusion compound [Zn(C2H5)2]0.38@ZIF-8 revealing two precursor molecules per cavity. In a second step the obtained material was treated with oxygen (5 vol% in argon) at various temperatures (oxidative annealing) to achieve the composite material ZnO0.35@ZIF-8. The new material was characterized with powder XRD, FT-IR, UV-vis, solid state NMR, elemental analysis, N2 sorption measurements, and transmission electron microscopy. The data give evidence for the presence of nano-sized ZnO particles stabilized by ZIF-8 showing a blue-shift of the UV-vis absorption caused by quantum size effect (QSE). The surface structure and reactivity of embedded ZnO nanoparticles were characterized via carbon dioxide adsorption at different temperatures monitored by ultra-high vacuum FTIR techniques. It was found that the surface of ZnO nanoparticles is dominated by polar OZnO and ZnZnO facets as well as by defect sites, which all exhibit high reactivity towards CO2 activation forming various adsorbed carbonate and chemisorbed CO2δ− species. |
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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 |
000289260000012 |
Publication Date |
2011-03-19 |
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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 |
0959-9428;1364-5501; |
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 |
76 |
Open Access |
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Notes |
Esteem 026019 |
Approved |
Most recent IF: NA |
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Call Number |
UA @ lucian @ c:irua:88641 |
Serial |
3936 |
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Permanent link to this record |
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Author |
Ma, J.; Duong, T.H.; Smits, M.; Verstraete, W.; Carballa, M. |
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Title |
Enhanced biomethanation of kitchen waste by different pre-treatments |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Bioresource technology |
Abbreviated Journal |
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Volume |
102 |
Issue |
2 |
Pages |
592-599 |
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Keywords |
A1 Journal article; Engineering sciences. Technology; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
Five different pre-treatments were investigated to enhance the solubilisation and anaerobic biodegradability of kitchen waste (
KW) in thermophilic batch and continuous tests. In the batch solubilisation tests, the highest and the lowest solubilisation efficiency were achieved with the thermo-acid and the pressuredepressure pre-treatments, respectively. However, in the batch biodegradability tests, the highest cumulative biogas production was obtained with the pressuredepressure method. In the continuous tests, the best performance in terms of an acceptable biogas production efficiency of 60% and stable in-reactor CODs and VFA concentrations corresponded to the pressuredepressure reactor, followed by freezethaw, acid, thermo-acid, thermo and control. The maximum OLR (5 g COD L−1 d−1) applied in the pressuredepressure and freezethaw reactors almost doubled the control reactor. From the overall analysis, the freezethaw pre-treatment was the most profitable process with a net potential profit of around 11.5 ton−1 KW. |
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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 |
000286782700022 |
Publication Date |
2010-08-12 |
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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 |
0960-8524 |
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:85249 |
Serial |
7910 |
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Permanent link to this record |
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Author |
Bultinck, E.; Bogaerts, A. |
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Title |
Characterization of an Ar/O2 magnetron plasma by a multi-species Monte Carlo model |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
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Volume |
20 |
Issue |
4 |
Pages |
045013-045013,12 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A combined Monte Carlo (MC)/analytical surface model is developed to study the plasma processes occurring during the reactive sputter deposition of TiOx thin films. This model describes the important plasma species with a MC approach (i.e. electrons, Ar+ ions, {\rm O}_2 |
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Corporate Author |
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Thesis |
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Publisher |
Institute of Physics |
Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
000295829800015 |
Publication Date |
2011-06-14 |
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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 |
0963-0252;1361-6595; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.302 |
Times cited |
7 |
Open Access |
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Notes |
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Approved |
Most recent IF: 3.302; 2011 IF: 2.521 |
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Call Number |
UA @ lucian @ c:irua:89732 |
Serial |
316 |
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Permanent link to this record |
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Author |
Tinck, S.; Bogaerts, A. |
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Title |
Computer simulations of an oxygen inductively coupled plasma used for plasma-assisted atomic layer deposition |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
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Volume |
20 |
Issue |
1 |
Pages |
015008-015008,10 |
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
|
|
Abstract |
In this paper, an O2 inductively coupled plasma used for plasma enhanced atomic layer deposition of Al2O3 thin films is investigated by means of modeling. This work intends to provide more information about basic plasma properties such as species densities and species fluxes to the substrate as a function of power and pressure, which might be hard to measure experimentally. For this purpose, a hybrid model developed by Kushner et al is applied to calculate the plasma characteristics in the reactor volume for different chamber pressures ranging from 1 to 10 mTorr and different coil powers ranging from 50 to 500 W. Density profiles of the various oxygen containing plasma species are reported as well as fluxes to the substrate under various operating conditions. Furthermore, different orientations of the substrate, which can be placed vertically or horizontally in the reactor, are taken into account. In addition, special attention is paid to the recombination process of atomic oxygen on the different reactor walls under the stated operating conditions. From this work it can be concluded that the plasma properties change significantly in different locations of the reactor. The plasma density near the cylindrical coil is high, while it is almost negligible in the neighborhood of the substrate. Ion and excited species fluxes to the substrate are found to be very low and negligible. Finally, the orientation of the substrate has a minor effect on the flux of O2, while it has a significant effect on the flux of O. In the horizontal configuration, the flux of atomic oxygen can be up to one order of magnitude lower than in the vertical configuration. |
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Address |
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Corporate Author |
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Thesis |
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|
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Publisher |
Institute of Physics |
Place of Publication |
Bristol |
Editor |
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|
Language |
|
Wos |
000286592200009 |
Publication Date |
2011-01-08 |
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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 |
0963-0252;1361-6595; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.302 |
Times cited |
11 |
Open Access |
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|
|
Notes |
|
Approved |
Most recent IF: 3.302; 2011 IF: 2.521 |
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Call Number |
UA @ lucian @ c:irua:85285 |
Serial |
467 |
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Permanent link to this record |
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Author |
De Bie, C.; Martens, T.; van Dijk, J.; Paulussen, S.; Verheyde, B.; Corthals, S.; Bogaerts, A. |
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Title |
Dielectric barrier discharges used for the conversion of greenhouse gases: modeling the plasma chemistry by fluid simulations |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
|
|
Volume |
20 |
Issue |
2 |
Pages |
024008,1-024008,11 |
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|
Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
The conversion of methane to value-added chemicals and fuels is considered to be one of the challenges of the 21st century. In this paper we study, by means of fluid modeling, the conversion of methane to higher hydrocarbons or oxygenates by partial oxidation with CO2 or O2 in a dielectric barrier discharge. Sixty-nine different plasma species (electrons, ions, molecules, radicals) are included in the model, as well as a comprehensive set of chemical reactions. The calculation results presented in this paper include the conversion of the reactants and the yields of the reaction products as a function of residence time in the reactor, for different gas mixing ratios. Syngas (i.e. H2 + CO) and higher hydrocarbons (C2Hx) are typically found to be important reaction products. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Institute of Physics |
Place of Publication |
Bristol |
Editor |
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Language |
|
Wos |
000290719900009 |
Publication Date |
2011-04-02 |
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Series Editor |
|
Series Title |
|
Abbreviated Series Title |
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|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0963-0252;1361-6595; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.302 |
Times cited |
38 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 3.302; 2011 IF: 2.521 |
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Call Number |
UA @ lucian @ c:irua:87868 |
Serial |
689 |
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Permanent link to this record |
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Author |
Tinck, S.; Boullart, W.; Bogaerts, A. |
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Title |
Modeling Cl2/O2/Ar inductively coupled plasmas used for silicon etching : effects of SiO2 chamber wall coating |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Plasma sources science and technology |
Abbreviated Journal |
Plasma Sources Sci T |
|
|
Volume |
20 |
Issue |
4 |
Pages |
045012-045012,19 |
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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 paper, simulations are performed to gain a better insight into the properties of a Cl2/Ar plasma, with and without O2, during plasma etching of Si. Both plasma and surface properties are calculated in a self-consistent manner. Special attention is paid to the behavior of etch products coming from the wafer or the walls, and how the chamber walls can affect the plasma and the resulting etch process. Two modeling cases are considered. In the first case, the reactor walls are defined as clean (Al2O3), whereas in the second case a SiO2 coating is introduced on the reactor walls before the etching process, so that oxygen will be sputtered from the walls and introduced into the plasma. For this reason, a detailed reaction set is presented for a Cl2/O2/Ar plasma containing etched species, as well as an extensive reaction set for surface processes, including physical and chemical sputtering, chemical etching and deposition processes. Density and flux profiles of various species are presented for a better understanding of the bulk plasma during the etching process. Detailed information is also given on the composition of the surfaces at various locations of the reactor, on the etch products in the plasma and on the surface loss probabilities of the plasma species at the walls, with different compositions. It is found that in the clean chamber, walls are mostly chlorinated (Al2Cl3), with a thin layer of etch products residing on the wall. In the coated chamber, an oxy-chloride layer is grown on the walls for a few nanometers during the etching process. The Cl atom wall loss probability is found to decrease significantly in the coated chamber, hence increasing the etch rate. SiCl2, SiCl4 and SiCl3 are found to be the main etch products in the plasma, with the fraction of SiCl2 being always slightly higher. The simulation results compare well with experimental data available from the literature. |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
Institute of Physics |
Place of Publication |
Bristol |
Editor |
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Language |
|
Wos |
000295829800014 |
Publication Date |
2011-06-14 |
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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 |
|
|
|
ISSN |
0963-0252;1361-6595; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
3.302 |
Times cited |
22 |
Open Access |
|
|
|
Notes |
|
Approved |
Most recent IF: 3.302; 2011 IF: 2.521 |
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Call Number |
UA @ lucian @ c:irua:91045 |
Serial |
2141 |
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Permanent link to this record |
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Author |
Leroux, O.; Leroux, F.; Bagniewska-Zadworna,.; Knox, J.P.; Claeys, M.; Bals, S.; Viane, R.L.L. |
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Title |
Ultrastructure and composition of cell wall appositions in the roots of Asplenium (Polypodiales) |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Micron |
Abbreviated Journal |
Micron |
|
|
Volume |
42 |
Issue |
8 |
Pages |
863-870 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Cell wall appositions (CWAs), formed by the deposition of extra wall material at the contact site with microbial organisms, are an integral part of the response of plants to microbial challenge. Detailed histological studies of CWAs in fern roots do not exist. Using light and electron microscopy we examined the (ultra)structure of CWAs in the outer layers of roots of Asplenium species. All cell walls studded with CWAs were impregnated with yellow-brown pigments. CWAs had different shapes, ranging from warts to elongated branched structures, as observed with scanning and transmission electron microscopy. Ultrastructural study further showed that infecting fungi grow intramurally and that they are immobilized by CWAs when attempting to penetrate intracellularly. Immunolabelling experiments using monoclonal antibodies indicated pectic homogalacturonan, xyloglucan, mannan and cellulose in the CWAs, but tests for lignins and callose were negative. We conclude that these appositions are defense-related structures made of a non-lignified polysaccharide matrix on which phenolic compounds are deposited in order to create a barrier protecting the root against infections. |
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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 |
000294942600013 |
Publication Date |
2011-06-24 |
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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 |
|
|
|
ISSN |
0968-4328; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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|
Impact Factor |
1.98 |
Times cited |
20 |
Open Access |
|
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|
Notes |
Fwo |
Approved |
Most recent IF: 1.98; 2011 IF: 1.527 |
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Call Number |
UA @ lucian @ c:irua:92540 |
Serial |
3798 |
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Permanent link to this record |
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Author |
Khalil-Allafi, J.; Amin-Ahmadi, B. |
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Title |
Effect of mold hardness on microstructure and contraction porosity in ductile cast iron |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Journal of iron and steel research international |
Abbreviated Journal |
J Iron Steel Res Int |
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Volume |
18 |
Issue |
4 |
Pages |
44-47 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The effect of mold hardness on the microstructure of ductile iron and the contraction porosity was investigated. Molds with different hardnesses (0.41, 0.48, 0.55, 0.62 MPa) and a sand mold prepared by Co2 method were used. The influence of silicon content on the induced expansion pressure owing to the formation of graphite was also investigated. The contraction during solidification can be compensated by an induced expansion owing to the graphite relief when the hardness of mold increases; therefore, the possibility of achieving a sound product without using any riser increases. |
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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 |
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Publication Date |
2011-05-01 |
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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 |
|
Series Issue |
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Edition |
|
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ISSN |
1006-706X; |
ISBN |
|
Additional Links |
UA library record |
|
|
Impact Factor |
0.836 |
Times cited |
1 |
Open Access |
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|
Notes |
|
Approved |
Most recent IF: 0.836; 2011 IF: 0.213 |
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Call Number |
UA @ lucian @ c:irua:122044 |
Serial |
823 |
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Permanent link to this record |
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Author |
Khalil-Allafi, J.; Amin-Ahmadi, B. |
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Title |
Influence of mold preheating and silicon content on microstructure and casting properties of ductile iron in permanent mold |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of iron and steel research international |
Abbreviated Journal |
J Iron Steel Res Int |
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Volume |
18 |
Issue |
3 |
Pages |
34-39 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The effects of the mold preheating and the silicon content of ductile iron on the percentage of carbides, graphite nodule counts and shrinkage volume were investigated. The results showed that the percentage of carbides and the shrinkage volume decreased when the mold preheating increased. The ductile iron with the carbon equivalent of 4.45% and the silicon content of 2.5% without any porosity defects was achieved when the mold preheating was 450 °C. Increasing the silicon content in the range of 2.1%3.3% led to the increase in graphite nodule count and graphite size and the decrease in percentage of carbides. It is due to the increase in induced expansion pressure during the graphite formation with the increasing of silicon content. The suitable condition for casting a sound product of ductile iron without the riser at the mold preheating temperature of 300 °C is the silicon content of 3.3% and carbon equivalent of 4.7%. |
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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 |
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Publication Date |
2011-03-28 |
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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 |
1006-706X; |
ISBN |
|
Additional Links |
UA library record |
|
|
Impact Factor |
0.836 |
Times cited |
3 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 0.836; 2011 IF: 0.213 |
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Call Number |
UA @ lucian @ c:irua:122043 |
Serial |
1629 |
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Permanent link to this record |
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Author |
Lin, H.; Ohta, T.; Paul, A.; Hutchison, J.A.; Kirilenko, D.; Lebedev, O.; Van Tendeloo, G.; Hofkens, J.; Uji-i, H. |
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Title |
Light-assisted nucleation of silver nanowires during polyol synthesis |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Journal of photochemistry and photobiology: A: chemistry |
Abbreviated Journal |
J Photoch Photobio A |
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Volume |
221 |
Issue |
2/3 |
Pages |
220-223 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
This report describes the effect of light irradiation on the synthesis of silver nanowires by the well-known polyol method. High quality nanowires are produced in high yields when the reaction suspension is irradiated with 400500 nm light during the nucleation stage. These studies suggest that light accelerates the formation of the nanoparticle seeds most appropriate for nanowire growth. |
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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 |
000293813800018 |
Publication Date |
2011-04-19 |
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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 |
1010-6030; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.625 |
Times cited |
24 |
Open Access |
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|
Notes |
Fwo; Iap |
Approved |
Most recent IF: 2.625; 2011 IF: 2.421 |
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Call Number |
UA @ lucian @ c:irua:91262 |
Serial |
1818 |
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Permanent link to this record |
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Author |
Corthals, S.; van Noyen, J.; Liang, D.; Ke, X.; Van Tendeloo, G.; Jacobs, P.; Sels, B. |
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Title |
A cyclic catalyst pretreatment in CO2 for high yield production of Carbon nanofibers with narrow diameter distribution |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Catalysis letters |
Abbreviated Journal |
Catal Lett |
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Volume |
141 |
Issue |
11 |
Pages |
1621-1624 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
This paper presents a cyclic catalyst pretreatment process to improve the CNF yield with narrow size distribution by sequentially feeding the CVD reactor with CH4/CO2 mixtures (carbon deposition) and CO2 (carbon removal) prior to the actual growth process. A mechanism based on a break-up of large Ni particles tentatively explains the beneficial effect of the cyclic carbon deposition/removal CVD procedure. |
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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 |
Basel |
Editor |
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Language |
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Wos |
000296471400006 |
Publication Date |
2011-09-26 |
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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 |
1011-372X;1572-879X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.799 |
Times cited |
1 |
Open Access |
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Notes |
Iwt; Iap |
Approved |
Most recent IF: 2.799; 2011 IF: 2.242 |
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Call Number |
UA @ lucian @ c:irua:91888 |
Serial |
598 |
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Permanent link to this record |
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Author |
Bertoni, G.; Verbeeck, J.; Brosens, F. |
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Title |
Fitting the momentum dependent loss function in EELS |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Microscopy research and technique |
Abbreviated Journal |
Microsc Res Techniq |
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Volume |
74 |
Issue |
3 |
Pages |
212-218 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT); Theory of quantum systems and complex systems |
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Abstract |
Momentum dependent inelastic plasmon scattering can be measured by electron energy loss in a transmission electron microscope. From energy filtered diffraction, the characteristic angle of scattering and the cutoff angle are measured, using a thin film of aluminum as a model test. Rather than deconvolving the data (as done in previous works), a fitting technique is used to extract the loss function from angular resolved spectra, starting from a simple model simulation. |
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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 |
000288095200002 |
Publication Date |
2010-07-06 |
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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 |
1059-910X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
1.147 |
Times cited |
6 |
Open Access |
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Notes |
Fwo; Esteem; Iap; Goa |
Approved |
Most recent IF: 1.147; 2011 IF: 1.792 |
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Call Number |
UA @ lucian @ c:irua:88782UA @ admin @ c:irua:88782 |
Serial |
1222 |
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Permanent link to this record |
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Author |
Zelaya, E.; Schryvers, D. |
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Title |
Reducing the formation of FIB-induced FCC layers on Cu-Zn-Al austenite |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Microscopy research and technique |
Abbreviated Journal |
Microsc Res Techniq |
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Volume |
74 |
Issue |
1 |
Pages |
84-91 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The irradiation effects of thinning a sample of a Cu-Zn-Al shape memory alloy to electron transparency by a Ga+ focused ion beam were investigated. This thinning method was compared with conventional electropolishing and Ar+ ion milling. No implanted Ga was detected but surface FCC precipitation was found as a result of the focused ion beam sample preparation. Decreasing the irradiation dose by lowering the energy and current of the Ga+ ions did not lead to a complete disappearance of the FCC structure. The latter could only be removed after gentle Ar+ ion milling of the sample. It was further concluded that the precipitation of the FCC is independent of the crystallographic orientation of the surface. |
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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 |
000285976000012 |
Publication Date |
2010-05-25 |
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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 |
1059-910X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
1.147 |
Times cited |
2 |
Open Access |
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Notes |
|
Approved |
Most recent IF: 1.147; 2011 IF: 1.792 |
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Call Number |
UA @ lucian @ c:irua:85994 |
Serial |
2852 |
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Permanent link to this record |
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Author |
Tkachenko, D.V.; Sheridan, T.E.; Misko, V.R. |
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Title |
Dispersion relations for circular single and double dusty plasma chains |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Physics of plasmas |
Abbreviated Journal |
Phys Plasmas |
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Volume |
18 |
Issue |
10 |
Pages |
103709,1-103709,10 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We derive dispersion relations for a system of identical particles confined in a two-dimensional annular harmonic well and which interact through a Yukawa potential, e.g., a dusty plasma ring. When the particles are in a single chain (i.e., a one-dimensional ring), we find a longitudinal acoustic mode and a transverse optical mode which show approximate agreement with the dispersion relation for a straight configuration for large radii of the ring. When the radius decreases, the dispersion relations modify: there appears an anticrossing of the modes near the crossing point resulting in a frequency gap between the lower and upper branches of the modified dispersion relations. For the double chain (i.e., a two-dimensional zigzag configuration), the dispersion relation has four branches: longitudinal acoustic and optical and transverse acoustic and optical. |
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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 |
Woodbury, N.Y. |
Editor |
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Language |
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Wos |
000296529600090 |
Publication Date |
2011-10-21 |
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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 |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1070-664X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
|
|
Impact Factor |
2.115 |
Times cited |
7 |
Open Access |
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|
Notes |
; We acknowledge fruitful discussions with F.M. Peeters, A. Matulis, and W.P. Ferreira. This work was supported by the “Odysseus” program of the Flemish Government and FWO-Vl. ; |
Approved |
Most recent IF: 2.115; 2011 IF: 2.147 |
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|
Call Number |
UA @ lucian @ c:irua:94052 |
Serial |
738 |
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Permanent link to this record |
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Author |
Si, X.-J.; Zhao, S.-X.; Xu, X.; Bogaerts, A.; Wang, Y.-N. |
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Title |
Fluid simulations of frequency effects on nonlinear harmonics in inductively coupled plasma |
Type |
A1 Journal article |
|
Year |
2011 |
Publication |
Physics of plasmas |
Abbreviated Journal |
Phys Plasmas |
|
|
Volume |
18 |
Issue |
3 |
Pages |
033504-033504,9 |
|
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Keywords |
A1 Journal article; Plasma Lab for Applications in Sustainability and Medicine – Antwerp (PLASMANT) |
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Abstract |
A fluid model is self-consistently established to investigate the harmonic effects in an inductively coupled plasma, where the electromagnetic field is solved by the finite difference time domain technique. The spatiotemporal distribution of harmonic current density, harmonic potential, and other plasma quantities, such as radio frequency power deposition, plasma density, and electron temperature, have been investigated. Distinct differences in current density have been observed when calculated with and without Lorentz force, which indicates that the nonlinear Lorentz force plays an important role in the harmonic effects, especially at low frequencies. Moreover, the even harmonics are larger than the odd harmonics both in the current density and the potential. Finally, the dependence of various plasma quantities with and without the Lorentz force on various driving frequencies is also examined. It is shown that the deposited power density decreases and the depth of penetration increases slightly because of the Lorentz force. The electron density increases distinctly while the electron temperature remains almost the same when the Lorentz force is taken into account. |
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Corporate Author |
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Place of Publication |
Woodbury, N.Y. |
Editor |
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Language |
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Wos |
000289151900073 |
Publication Date |
2011-03-18 |
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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 |
1070-664X; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
2.115 |
Times cited |
7 |
Open Access |
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Notes |
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Approved |
Most recent IF: 2.115; 2011 IF: 2.147 |
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Call Number |
UA @ lucian @ c:irua:87876 |
Serial |
1233 |
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Permanent link to this record |
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Author |
Caratelli, D.; Gielis, J.; Natalini, P.; Ricci, P.E.; Tavkhelidze, I. |
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Title |
The Robin problem for the Helmholtz equation in a starlike planar domain |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Georgian mathematical journal |
Abbreviated Journal |
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Volume |
18 |
Issue |
3 |
Pages |
465-479 |
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Keywords |
A1 Journal article; Sustainable Energy, Air and Water Technology (DuEL) |
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Abstract |
The interior and exterior Robin problems for the Helmholtz equation in starlike planar domains are addressed by using a suitable Fourier-like technique. Attention is in particular focused on normal-polar domains whose boundaries are defined by the so-called superformula introduced by J. Gielis. A dedicated numerical procedure based on the computer algebra system Mathematica© is developed in order to validate the proposed approach. In this way, highly accurate approximations of the solution, featuring properties similar to the classical ones, are obtained. The computed results are found to be in good agreement with the theoretical findings on Fourier series expansion presented by L. Carleson. |
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Thesis |
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Place of Publication |
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Language |
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Wos |
000296166100004 |
Publication Date |
2021-02-28 |
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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 |
1072-947x |
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:91086 |
Serial |
8658 |
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Permanent link to this record |
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Author |
Shestakov, M.V.; Tikhomirov, V.K.; Kirilenko, D.; Kuznetsov, A.S.; Chibotaru, L.F.; Baranov, A.N.; Van Tendeloo, G.; Moshchalkov, V.V. |
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Title |
Quantum cutting in Li (770 nm) and Yb (1000 nm) co-dopant emission bands by energy transfer from the ZnO nano-crystalline host |
Type |
A1 Journal article |
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Year |
2011 |
Publication |
Optics express |
Abbreviated Journal |
Opt Express |
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Volume |
19 |
Issue |
17 |
Pages |
15955-15964 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
Li-Yb co-doped nano-crystalline ZnO has been synthesized by a method of thermal growth from the salt mixtures. X-ray diffraction, transmission electron microscopy, atomic absorption spectroscopy and optical spectroscopy confirm the doping and indicate that the dopants may form Li-Li and Yb3+-Li based nanoclusters. When pumped into the conduction and exciton absorption bands of ZnO between 250 to 425 nm, broad emission bands of about 100 nm half-height-width are excited around 770 and 1000 nm, due to Li and Yb dopants, respectively. These emission bands are activated by energy transfer from the ZnO host mostly by quantum cutting processes, which generate pairs of quanta in Li (770 nm) and Yb (1000 nm) emission bands, respectively, out of one quantum absorbed by the ZnO host. These quantum cutting phenomena have great potential for application in the down-conversion layers coupled to the Si solar cells. |
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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 |
000293894900033 |
Publication Date |
2011-08-04 |
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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 |
1094-4087; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.307 |
Times cited |
19 |
Open Access |
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Notes |
FWO; Methusalem |
Approved |
Most recent IF: 3.307; 2011 IF: 3.587 |
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Call Number |
UA @ lucian @ c:irua:92428 |
Serial |
2776 |
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Permanent link to this record |
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Author |
Matulis, A.; Masir, M.R.; Peeters, F.M. |
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Title |
Application of optical beams to electrons in 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 |
83 |
Issue |
11 |
Pages |
115458-115458,7 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
The technique of beam optics is applied to the description of the wave function of Dirac electrons. This approach is illustrated by considering electron transmission through simple nonhomogeneous structures, such as flat and bent p-n junctions and superlattices. We found that a convex p-n junction compresses the beam waist, while a concave interface widens it without loosing its focusing properties. At a flat p-n junction the waist of the transmitted Gaussian beam can be narrowed or widened, depending on the angle of incidence. A general condition is derived for the occurrence of beam collimation in a superlattice which is less stringent than previous discussed. |
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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 |
000288896400013 |
Publication Date |
2011-03-29 |
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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 |
13 |
Open Access |
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Notes |
; This research was supported by the Flemish Science Foundation (Grant No. FWO-Vl), by the Belgian Science policy (IAP), and (in part) by the Lithuanian Science Council under project No. MIP-79/2010. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:89377 |
Serial |
142 |
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Permanent link to this record |
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Author |
Zarenia, M.; Pereira, J.M.; Farias, G.A.; Peeters, F.M. |
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Title |
Chiral states in bilayer graphene : magnetic field dependence and gap opening |
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 |
12 |
Pages |
125451-125451,13 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
At the interface of electrostatic potential kink profiles, one-dimensional chiral states are found in bilayer graphene (BLG). Such structures can be created by applying an asymmetric potential to the upper and the lower layers of BLG. We found the following: (i) due to the strong confinement by the single kink profile, the unidirectional states are only weakly affected by a magnetic field; (ii) increasing the smoothness of the kink potential results in additional bound states, which are topologically different from those chiral states; and (iii) in the presence of a kink-antikink potential, the overlap between the oppositely moving chiral states results in the appearance of crossing and anticrossing points in the energy spectrum. This leads to the opening of tunable minigaps in the spectrum of the unidirectional topological states. |
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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 |
000295484300016 |
Publication Date |
2011-09-30 |
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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 |
50 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-VI), the Belgian Science Policy (IAP), the European Science Foundation (ESF) under the EUROCORES program EuroGRAPHENE (project CONGRAN), the Brazilian agency CNPq (Pronex), and the bilateral projects between Flanders and Brazil and the collaboration project FWO-CNPq. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92915 |
Serial |
358 |
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Permanent link to this record |
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Author |
Chaves, A.; Komendová, L.; Milošević, M.V.; Andrade, J.S.; Farias, G.A.; Peeters, F.M. |
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Title |
Conditions for nonmonotonic vortex interaction in two-band superconductors |
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 |
83 |
Issue |
21 |
Pages |
214523-214523,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We describe a semianalytic approach to the two-band Ginzburg-Landau theory, which predicts the behavior of vortices in two-band superconductors. We show that the character of the short-range vortex-vortex interaction is determined by the sign of the normal domain-superconductor interface energy, in analogy with the conventional differentiation between type I and type II superconductors. However, we also show that the long-range interaction is determined by a modified Ginzburg-Landau parameter κ*, different from the standard κ of a bulk superconductor. This opens the possibility for nonmonotonic vortex-vortex interaction, which is temperature dependent, and can be further tuned by alterations of the material on the microscopic scale. |
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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 |
000292252300009 |
Publication Date |
2011-06-30 |
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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 |
46 |
Open Access |
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Notes |
; Discussions with A. Moreira, A. Shanenko, R. Prozorov, and A. Golubov are gratefully acknowledged. This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), the bilateral project FWO-CNPq, CAPES, and PRONEX/CNPq/FUNCAP. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:90922 |
Serial |
477 |
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Permanent link to this record |
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Author |
Peelaers, H.; Partoens, B.; Giantomassi, M.; Rangel, T.; Goossens, E.; Rignanese, G.-M.; Gonze, X.; Peeters, F.M. |
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Title |
Convergence of quasiparticle band structures of Si and Ge nanowires in the GW approximation and the validity of scissor shifts |
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 |
83 |
Issue |
4 |
Pages |
045306-045306,6 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Starting from fully converged density-functional theory calculations, the quasiparticle corrections are calculated for different sized Si and Ge nanowires using the GW approximation. The effectiveness of recently developed techniques in speeding up the convergence of the quasiparticle calculations is demonstrated. The complete quasiparticle band structures are also obtained using an interpolation technique based on maximallylocalized Wannier functions. From the quasiparticle results, we assess the correctness of the commonly applied scissor-shift correction. Dispersion changes are observed, which are also reflected in changes in the effective band masses calculated taking into account quasiparticle corrections. |
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Corporate Author |
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Place of Publication |
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Editor |
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Language |
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Wos |
000286771400004 |
Publication Date |
2011-01-21 |
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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 |
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 |
18 |
Open Access |
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Notes |
; We are grateful to Yann Pouillon for valuable technical support with the build system of ABINIT, related to the WANNIER90 library. This work was supported by the Flemish Science Foundation (FWO-Vl) and by the Interuniversity Attraction Poles Program (P6/42)-Belgian State-Belgian Science Policy. X. G. and G.-M. R. acknowledge funding from the EU's 7th Framework Programme through the ETSF I3 e-Infrastructure project (Grant No. 211956), the Communaute francaise de Belgique through the Action de Recherche Concertee 07/12-003 “Nanosystemes hybrides metal-organiques,” and the Wallon Region Project No. 816849 “ European Theoretical Spectroscopy Facility” (WALL ETSF). M. G. acknowledges funding from the 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:86905 |
Serial |
510 |
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Permanent link to this record |
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Author |
Klimczuk, T.; Wang, C.H.; Lawrence, J.M.; Xu, Q.; Durakiewicz, T.; Ronning, F.; Llobet, A.; Trouw, F.; Kurita, N.; Tokiwa, Y.; Lee, H.o.; Booth, C.H.; Gardner, J.S.; Bauer, E.D.; Joyce, J.J.; Zandbergen, H.W.; Movshovich, R.; Cava, R.J.; Thompson, J.D.; |
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Title |
Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru |
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 |
7 |
Pages |
075152-075152,8 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that crystallizes in the cubic CsCl structure. Valence-band photoemission (PES) and L3 x-ray absorption show no divalent component in the 4f configuration of Yb. Inelastic neutron scattering (INS) indicates that the eight-fold degenerate J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a Γ7-doublet ground state and a Γ8 quartet at an excitation energy 20 meV. The magnetic susceptibility can be fit very well by this CEF scheme under the assumption that a Γ6-excited state resides at 32 meV; however, the Γ8/Γ6 transition expected at 12 meV was not observed in the INS. The resistivity follows a Bloch-Grüneisen law shunted by a parallel resistor, as is typical of systems subject to phonon scattering with no apparent magnetic scattering. All of these properties can be understood as representing simple local moment behavior of the trivalent Yb ion. At 1 K there is a peak in specific heat that is too broad to represent a magnetic-phase transition, consistent with absence of magnetic reflections in neutron diffraction. On the other hand this peak also is too narrow to represent the Kondo effect in the Γ7-doublet ground state. On the basis of the field dependence of the specific heat, we argue that antiferromagnetic (AF) short-range order (SRO) (possibly coexisting with Kondo physics) occurs at low temperatures. The long-range magnetic order is suppressed because the Yb site occupancy is below the percolation threshold for this disordered compound. |
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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 |
000293830800003 |
Publication Date |
2011-08-15 |
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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 |
8 |
Open Access |
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Notes |
Esteem 026019 |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92427 |
Serial |
555 |
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Permanent link to this record |
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Author |
Komendová, L.; Milošević, M.V.; Shanenko, A.A.; Peeters, F.M. |
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Title |
Different length scales for order parameters in two-gap superconductors : extended Ginzburg-Landau theory |
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 |
6 |
Pages |
064522-064522,5 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Using the Ginzburg-Landau theory extended to the next-to-leading order, we determine numerically the healing lengths of the two order parameters at the two-gap superconductor/normal metal interface. We demonstrate on several examples that those can be different even in the strict domain of applicability of the Ginzburg-Landau theory. This justifies the use of this theory to describe relevant physics of two-gap superconductors, distinguishing them from their single-gap counterparts. The calculational degree of complexity increases only slightly with respect to the conventional Ginzburg-Landau expansion, thus the extended Ginzburg-Landau model remains numerically far less demanding compared to the full microscopic approaches. |
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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 |
000294226000013 |
Publication Date |
2011-08-25 |
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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 |
56 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl), the Belgian Science Policy (IAP), and the ESF-INSTANS network. ; |
Approved |
Most recent IF: 3.836; 2011 IF: 3.691 |
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Call Number |
UA @ lucian @ c:irua:92414 |
Serial |
695 |
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Permanent link to this record |