Records |
Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Sebhatu, K.T.; Taheri, F.; Berhanu, T.; Maertens, M.; Van Passel, S.; D'Haese, M. |
Title |
Beyond focus : exploring variability of service provision of agricultural cooperatives |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Annals of public and cooperative economics |
Abbreviated Journal |
|
Volume |
92 |
Issue |
2 |
Pages |
207-231 |
Keywords |
A1 Journal article; Economics; Engineering Management (ENM) |
Abstract |
The wide array of services provided by agricultural cooperatives for their members is often not considered in academic studies. Addressing this gap in the literature, our paper explores the wide array of services provided by agricultural cooperatives and how these extend beyond those they were initially intended to provide. We study the extent and characteristics of service portfolios from 511 agricultural cooperatives in the Tigray region of Ethiopia. Results from two-limit Tobit models confirm that government and NGO-initiated cooperatives have a wide service portfolio compared to member-initiated cooperatives. In many of the studied cooperatives, the services they provide and their portfolios are more diverse than expected. Cooperatives seem to go beyond their focal areas of intervention. Also, those cooperatives that are more outward-oriented and where the chair has contact with other cooperatives or businesses, have a wider service portfolio. These results may help to explain the mixed findings on the impact of cooperative membership. |
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Wos |
000583855500001 |
Publication Date |
2020-10-27 |
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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 |
1370-4788; 1467-8292 |
ISBN |
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Additional Links |
UA library record; WoS full record |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:173574 |
Serial |
6916 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Sebhatu, K.T.; Gezahegn, T.W.; Berhanu, T.; Maertens, M.; Van Passel, S.; D’Haese, M. |
Title |
Conflict, fraud, and distrust in Ethiopian agricultural cooperatives |
Type |
A1 Journal Article |
Year |
2020 |
Publication |
Journal of Co-operative Organization and Management |
Abbreviated Journal |
Journal of Co-operative Organization and Management |
Volume |
8 |
Issue |
1 |
Pages |
100106 |
Keywords |
A1 Journal Article; Agricultural cooperatives; Cooperative size; Conflict; Fraud; Distrust; Ethiopia; Engineering Management (ENM) ; |
Abstract |
Agricultural cooperatives are seen as an efficient way for smallholder farmers to create bargaining power in order to achieve poverty reduction and food security. However, the success of these cooperatives depends on their ability to maintain their social capital, which is at the core of collective action. A few studies have addressed issues of member participation, commitment, and trust, yet less is known about rural cooperatives in developing countries as a social organization. It is also unclear whether a relationship exists between cooperative size and the incidence of conflict, fraud, and distrust. Using unique data collected from 511 agricultural cooperatives in 12 districts of Tigray region in northern Ethiopia, this paper examines the effects of cooperative size on conflict, fraud, and distrust. We used instrumental variables (IV) probit estimation techniques, accounting for endogeneity of membership size, to confirm that cooperative size does affect the occurrence of conflict, fraud, and trust. The results also indicate that other influencing factors include: cooperative age, number of employees, payment of dividends based on transaction volume, and heterogeneity of member goals. |
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Wos |
000536594400001 |
Publication Date |
2020-04-28 |
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 |
2213297X |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
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Notes |
The authors would like to thank the office of the twelve districts, facilitators and Cooperative Promotion Agency staff for their collaboration in facilitating the field survey, most of all the chair- and vice-chairpersons of the study Agricultural Cooperatives who had to respond to all our questions with seriousness and patience. |
Approved |
Most recent IF: NA |
Call Number |
ENM @ enm @c:irua:170073 |
Serial |
6379 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Sebhatu, K.T.; Gezahegn, T.W.; Berhanu, T.; Maertens, M.; Van Passel, S.; D'Haese, M. |
Title |
Exploring variability across cooperatives : economic performance of agricultural cooperatives in northern Ethiopia |
Type |
A1 Journal article |
Year |
2021 |
Publication |
The international food and agribusiness management review |
Abbreviated Journal |
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Volume |
24 |
Issue |
3 |
Pages |
397-419 |
Keywords |
A1 Journal article; Engineering Management (ENM) |
Abstract |
The number of agricultural cooperatives increased quickly in Ethiopia since the 1990s. While many papers studied the impact of membership of Ethiopian cooperatives, not much is known on their performance. This study takes a cooperative-level perspective which is unique in an African context. It compares the economic performance proxied by sales revenue and profit of a wide range of agricultural cooperatives in northern Ethiopia. Data were collected from 511 agricultural cooperatives in 12 districts of Tigray. The contributing factors of the performance are analyzed with Ordinary Least Squares regression (OLS) and Heckman selection models. Our results underscore the importance of membership size, total assets, presence of conflict among members, and union membership. Chairperson characteristics and the internal organization of a cooperative seem to be less correlated to performance. |
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Wos |
000645416400002 |
Publication Date |
2021-03-01 |
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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 |
1096-7508; 1559-2448 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:179025 |
Serial |
6923 |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scuracchio, P.; Michel, K.H.; Peeters, F.M. |
Title |
Phonon hydrodynamics, thermal conductivity, and second sound in two-dimensional crystals |
Type |
A1 Journal article |
Year |
2019 |
Publication |
Physical review B |
Abbreviated Journal |
Phys Rev B |
Volume |
99 |
Issue |
14 |
Pages |
144303 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Starting from our previous work in which we obtained a system of coupled integrodifferential equations for acoustic sound waves and phonon density fluctuations in two-dimensional (2D) crystals, we derive here the corresponding hydrodynamic equations, and we study their consequences as a function of temperature and frequency. These phenomena encompass propagation and damping of acoustic sound waves, diffusive heat conduction, second sound, and Poiseuille heat flow, all of which are characterized by specific transport coefficients. We calculate these coefficients by means of correlation functions without using the concept of relaxation time. Numerical calculations are performed as well in order to show the temperature dependence of the transport coefficients and of the thermal conductivity. As a consequence of thermal tension, mechanical and thermal phenomena are coupled. We calculate the dynamic susceptibilities for displacement and temperature fluctuations and study their resonances. Due to the thermomechanical coupling, the thermal resonances such as the Landau-Placzek peak and the second-sound doublet appear in the displacement susceptibility, and conversely the acoustic sound wave doublet appears in the temperature susceptibility, Our analytical results not only apply to graphene, but they are also valid for arbitrary 2D crystals with hexagonal symmetry, such as 2D hexagonal boron nitride, 2H-transition-metal dichalcogenides, and oxides. |
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Wos |
000464717300006 |
Publication Date |
2019-04-10 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9969; 2469-9950 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
16 |
Open Access |
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Notes |
; This work was supported by the Flemish Science Foundation (FWO-Vl). ; |
Approved |
Most recent IF: 3.836 |
Call Number |
UA @ admin @ c:irua:159346 |
Serial |
5225 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scuracchio, P.; Dobry, A.; Costamagna, S.; Peeters, F.M. |
Title |
Tuning the polarized quantum phonon transmission in graphene nanoribbons |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Nanotechnology |
Abbreviated Journal |
Nanotechnology |
Volume |
26 |
Issue |
26 |
Pages |
305401 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
We propose systems that allow a tuning of the phonon transmission function T(omega) in graphene nanoribbons by using C-13 isotope barriers, antidot structures, and distinct boundary conditions. Phonon modes are obtained by an interatomic fifth-nearest neighbor force-constant model (5NNFCM) and T(omega) is calculated using the non-equilibrium Green's function formalism. We show that by imposing partial fixed boundary conditions it is possible to restrict contributions of the in-plane phonon modes to T(omega) at low energy. On the contrary, the transmission functions of out-of-plane phonon modes can be diminished by proper antidot or isotope arrangements. In particular, we show that a periodic array of them leads to sharp dips in the transmission function at certain frequencies omega(nu) which can be pre-defined as desired by controlling their relative distance and size. With this, we demonstrated that by adequate engineering it is possible to govern the magnitude of the ballistic transmission functions T(omega) in graphene nanoribbons. We discuss the implications of these results in the design of controlled thermal transport at the nanoscale as well as in the enhancement of thermo-electric features of graphene-based materials. |
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Corporate Author |
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Publisher |
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Place of Publication |
Bristol |
Editor |
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Language |
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Wos |
000358675900010 |
Publication Date |
2015-07-07 |
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 |
0957-4484;1361-6528; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.44 |
Times cited |
5 |
Open Access |
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Notes |
; Discussions with C E Repetto, C R Stia and K H Michel are gratefully acknowledged. This work was partially supported by the Flemish Science Foundation (FWO-Vl) and PIP 11220090100392 of CONICET (Argentina). We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. ; |
Approved |
Most recent IF: 3.44; 2015 IF: 3.821 |
Call Number |
c:irua:127186 |
Serial |
3759 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scuracchio, P.; Costamagna; Peeters, F.M.; Dobry, A. |
Title |
Role of atomic vacancies and boundary conditions on ballistic thermal transport in graphene nanoribbons |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
90 |
Issue |
3 |
Pages |
035429 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
Quantum thermal transport in armchair and zigzag graphene nanoribbons is investigated in the presence of single atomic vacancies and subject to different boundary conditions. We start with a full comparison of the phonon polarizations and energy dispersions as given by a fifth-nearest-neighbor force-constant model (5NNFCM) and by elasticity theory of continuum membranes (ETCM). For free-edge ribbons, we discuss the behavior of an additional acoustic edge-localized flexural mode, known as fourth acoustic branch (4ZA), which has a small gap when it is obtained by the 5NNFCM. Then, we show that ribbons with supported edges have a sample-size dependent energy gap in the phonon spectrum which is particularly large for in-plane modes. Irrespective to the calculation method and the boundary condition, the dependence of the energy gap for the low-energy optical phonon modes against the ribbon width W is found to be proportional to 1/W for in-plane, and 1/W-2 for out-of-plane phonon modes. Using the 5NNFCM, the ballistic thermal conductance and its contributions from every single phonon mode are then obtained by the nonequilibrium Green's function technique. We found that, while edge and central localized single atomic vacancies do not affect the low-energy transmission function of in-plane phonon modes, they reduce considerably the contributions of the flexural modes. On the other hand, in-plane modes contributions are strongly dependent on the boundary conditions and at low temperatures can be highly reduced in supported-edge samples. These findings could open a route to engineer graphene based devices where it is possible to discriminate the relative contribution of polarized phonons and to tune the thermal transport on the nanoscale. |
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Wos |
000339443800009 |
Publication Date |
2014-07-21 |
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 |
Impact Factor |
3.836 |
Times cited |
20 |
Open Access |
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Notes |
; Discussions with S. D. Dalosto and K. H. Michel are gratefully acknowledged. This work was partially supported by PIP 11220090100392 of CONICET (Argentina) and the Flemish Science Foundation (FWO-VI). We acknowledge funding from the FWO (Belgium)-MINCyT (Argentina) collaborative research project. ; |
Approved |
Most recent IF: 3.836; 2014 IF: 3.736 |
Call Number |
UA @ lucian @ c:irua:118698 |
Serial |
2911 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scotti di Uccio, U.; Miletto Granozio, F.; di Chiara, A.; Tafuri, F.; Lebedev, O.I.; Verbist, K.; Van Tendeloo, G. |
Title |
Phase competition between Y2BaCuO5 and Y2O3 precipitates in Y-rich YBCO thin films |
Type |
A1 Journal article |
Year |
1999 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
321 |
Issue |
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Pages |
162-176 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000083004400004 |
Publication Date |
0000-00-00 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0921-4534 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.404 |
Times cited |
17 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.404; 1999 IF: 1.114 |
Call Number |
UA @ lucian @ c:irua:29725 |
Serial |
2579 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scot, V.; Fernandez, J.E.; Vincze, L.; Janssens, K. |
Title |
3D extension of the Monte Carlo code MCSHAPE for photon-matter interactions in the heterogeneous media |
Type |
A1 Journal article |
Year |
2007 |
Publication |
Nuclear instruments & methods in physics research section B-Beam interactions with materiala and atoms |
Abbreviated Journal |
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Volume |
263 |
Issue |
1 |
Pages |
204-208 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
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Address |
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Thesis |
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Publisher |
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Place of Publication |
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Wos |
000250798000042 |
Publication Date |
2007-04-25 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
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ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
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Times cited |
15 |
Open Access |
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Notes |
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Approved |
Most recent IF: NA |
Call Number |
UA @ admin @ c:irua:66755 |
Serial |
5448 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scolfaro, D.; Finamor, M.; Trinchao, L.O.; Rosa, B.L.T.; Chaves, A.; Santos, P., V.; Iikawa, F.; Couto, O.D.D., Jr. |
Title |
Acoustically driven stark effect in transition metal dichalcogenide monolayers |
Type |
A1 Journal article |
Year |
2021 |
Publication |
Acs Nano |
Abbreviated Journal |
Acs Nano |
Volume |
15 |
Issue |
9 |
Pages |
15371-15380 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Condensed Matter Theory (CMT) |
Abstract |
The Stark effect is one of the most efficient mechanisms to manipulate many-body states in nanostructured systems. In mono- and few-layer transition metal dichalcogenides, it has been successfully induced by optical and electric field means. Here, we tune the optical emission energies and dissociate excitonic states in MoSe2 monolayers employing the 220 MHz in-plane piezoelectric field carried by surface acoustic waves. We transfer the monolayers to high dielectric constant piezoelectric substrates, where the neutral exciton binding energy is reduced, allowing us to efficiently quench (above 90%) and red-shift the excitonic optical emissions. A model for the acoustically induced Stark effect yields neutral exciton and trion in-plane polarizabilities of 530 and 630 x 10(-5) meV/(kV/cm)(2), respectively, which are considerably larger than those reported for monolayers encapsulated in hexagonal boron nitride. Large in-plane polarizabilities are an attractive ingredient to manipulate and modulate multiexciton interactions in two-dimensional semiconductor nanostructures for optoelectronic applications. |
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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 |
000703553600129 |
Publication Date |
2021-08-27 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1936-0851 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
13.942 |
Times cited |
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Open Access |
OpenAccess |
Notes |
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Approved |
Most recent IF: 13.942 |
Call Number |
UA @ admin @ c:irua:182545 |
Serial |
7415 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Sciutto, G.; Legrand, S.; Catelli, E.; Prati, S.; Malegori, C.; Oliveri, P.; Janssens, K.; Mazzeo, R. |
Title |
Macroscopic mid-FTIR mapping and clustering-based automated data-reduction : an advanced diagnostic tool for in situ investigations of artworks |
Type |
A1 Journal article |
Year |
2020 |
Publication |
Talanta |
Abbreviated Journal |
Talanta |
Volume |
209 |
Issue |
|
Pages |
120575-120577 |
Keywords |
A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation) |
Abstract |
The present study describes a multivariate strategy that can be used for automatic on-site processing of reflection mode macro FTIR mapping (MA-rFTIR) data obtained during investigation of artworks. The chemometric strategy is based on the integration of principal component analysis (PCA) with a clustering approach in the space subtended by the three lowest-order principal components and allows to automatically identify the regions of interest (ROIs) of the area scanned and to extract the average FTIR spectra related to each ROI. Thanks to the automatic data management, in-field HSI (hyperspectral imaging)-based analyses may be performed even by staff lacking specific advanced chemometric expertise, as it is sometimes the case for conservation scientists or conservators with a scientific background. MA-rFTIR was only recently introduced in the conservation field and, in this work the technique was employed to characterize the surface of metallic artefacts. The analytical protocol was employed as part of a rapid procedure to evaluate the conservation state and the performance of cleaning methods on bronze objects. Both activities are commonly part of restoration campaigns of bronzes and require an on-site analytical procedure for efficient and effective diagnosis. The performance of the method was first evaluated on aged standard samples (bronzes with a layer of green basic copper hydroxysulphate, treated with different organic coatings) and then scrutinized in situ on areas of the 16th century Neptune fountain statue (Piazza del Nettuno, Bologna, Italy) by Gianbologna. |
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Place of Publication |
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Language |
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Wos |
000509632900088 |
Publication Date |
2019-11-19 |
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 |
0039-9140; 1873-3573 |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
6.1 |
Times cited |
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Open Access |
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Notes |
; ; |
Approved |
Most recent IF: 6.1; 2020 IF: 4.162 |
Call Number |
UA @ admin @ c:irua:166476 |
Serial |
6557 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Scipioni, R.; Matsubara, M.; Ruiz, E.; Massobrio, C.; Boero, M. |
Title |
Thermal behavior of Si-doped fullerenes vs their structural stability at T = 0 K : a density functional study |
Type |
A1 Journal article |
Year |
2011 |
Publication |
Chemical physics letters |
Abbreviated Journal |
Chem Phys Lett |
Volume |
510 |
Issue |
1/3 |
Pages |
14-17 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
We establish the topological conditions underlying the thermal stability of C30Si30 clusters. Two topologies have been considered: a segregated one, where Si and C atoms lie on neighboring and yet, separated parts of the cage, and a non-segregated one, where the number of SiC bonds is maximized. The segregated network is energetically favored against the non-segregated one, both structures being fully relaxed at T = 0 K. Conversely, the non-segregated structure is the only one stable at finite temperatures, regardless of the nature of the local states (d or p) included in the KleynmanBylander construction. |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Amsterdam |
Editor |
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Language |
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Wos |
000291478400002 |
Publication Date |
2011-05-20 |
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 |
0009-2614; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.815 |
Times cited |
14 |
Open Access |
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Notes |
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Approved |
Most recent IF: 1.815; 2011 IF: 2.337 |
Call Number |
UA @ lucian @ c:irua:90453 |
Serial |
3625 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M.; Deo, P.S. |
Title |
Vortex phase diagram for mesoscopic superconducting disks |
Type |
A1 Journal article |
Year |
1998 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
81 |
Issue |
|
Pages |
2783-2786 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
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Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000076133300041 |
Publication Date |
2002-07-27 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0031-9007;1079-7114; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
327 |
Open Access |
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Notes |
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Approved |
Most recent IF: 8.462; 1998 IF: 6.017 |
Call Number |
UA @ lucian @ c:irua:24154 |
Serial |
3879 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Dynamics of a finite classical two-dimensional system |
Type |
A1 Journal article |
Year |
1994 |
Publication |
Superlattices and microstructures |
Abbreviated Journal |
Superlattice Microst |
Volume |
16 |
Issue |
3 |
Pages |
243-247 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The spectral properties of a classical two-dimensional (2D) cluster of charged particles which are confined by a quadratic potential are calculated. Using the method of Newton optimization we obtain the ground state and the metastable states. For a given configuration the eigenvectors and eigenfrequencies for the normal modes are obtained using the Householder diagonalization technique for the dynamical matrix whose elements are the second derivative of the potential energy. For small clusters the lowest excitation corresponds to an intershell rotation. Magic numbers are associated to clusters which are most stable against intershell rotation. For large clusters the lowest excitation is a vortex/anti-vortex pair. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
London |
Editor |
|
Language |
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Wos |
A1994QE75400007 |
Publication Date |
2009-07-08 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0749-6036; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.097 |
Times cited |
4 |
Open Access |
|
Notes |
|
Approved |
no |
Call Number |
UA @ lucian @ c:irua:99951 |
Serial |
772 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Filed-cooled vortex states in mesoscopic superconducting samples |
Type |
A1 Journal article |
Year |
2000 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
180 |
Issue |
|
Pages |
426-431 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000087245200080 |
Publication Date |
2002-07-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.404 |
Times cited |
17 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 1.404; 2000 IF: 1.489 |
Call Number |
UA @ lucian @ c:irua:28523 |
Serial |
1193 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Flux penetration and expulsion in thin superconducting disks |
Type |
A1 Journal article |
Year |
1999 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
83 |
Issue |
|
Pages |
2409-2412 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
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Language |
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Wos |
000082661100033 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
104 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 1999 IF: 6.095 |
Call Number |
UA @ lucian @ c:irua:26998 |
Serial |
1241 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Influence of the confinement geometry on surface superconductivity |
Type |
A1 Journal article |
Year |
1999 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
60 |
Issue |
|
Pages |
3084-3087 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
000081986300033 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0163-1829;1095-3795; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
88 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 1999 IF: NA |
Call Number |
UA @ lucian @ c:irua:27015 |
Serial |
1646 |
Permanent link to this record |
|
|
|
Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Phase transitions in thin mesoscopic superconducting disks |
Type |
A1 Journal article |
Year |
1998 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
57 |
Issue |
|
Pages |
13817-13832 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
000074061700068 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0163-1829;1095-3795; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
200 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 1998 IF: NA |
Call Number |
UA @ lucian @ c:irua:24167 |
Serial |
2598 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Spectral properties of classical two-dimensional clusters |
Type |
A1 Journal article |
Year |
1995 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
51 |
Issue |
|
Pages |
7700-7713 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
A1995QQ59800034 |
Publication Date |
0000-00-00 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1098-0121; 0163-1829 |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.736 |
Times cited |
237 |
Open Access |
|
Notes |
|
Approved |
CHEMISTRY, PHYSICAL 77/144 Q3 # MATHEMATICS, INTERDISCIPLINARY 19/101 Q1 # PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 17/35 Q2 # |
Call Number |
UA @ lucian @ c:irua:12198 |
Serial |
3072 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Time dependent properties of classical artificial atoms |
Type |
A1 Journal article |
Year |
1998 |
Publication |
Journal of physics : condensed matter |
Abbreviated Journal |
J Phys-Condens Mat |
Volume |
10 |
Issue |
|
Pages |
2417-2435 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
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Place of Publication |
London |
Editor |
|
Language |
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Wos |
000072951000006 |
Publication Date |
2002-08-25 |
Series Editor |
|
Series Title |
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Abbreviated Series Title |
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Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0953-8984;1361-648X; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.649 |
Times cited |
18 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.649; 1998 IF: 1.645 |
Call Number |
UA @ lucian @ c:irua:24175 |
Serial |
3665 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, V.A.; Peeters, F.M. |
Title |
Transitions between different superconducting states in mesoscopic disks |
Type |
A1 Journal article |
Year |
2000 |
Publication |
Physica: C : superconductivity |
Abbreviated Journal |
Physica C |
Volume |
144 |
Issue |
|
Pages |
266-271 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Amsterdam |
Editor |
|
Language |
|
Wos |
000087245200047 |
Publication Date |
2002-07-26 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0921-4534; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
1.404 |
Times cited |
24 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 1.404; 2000 IF: 1.489 |
Call Number |
UA @ lucian @ c:irua:28521 |
Serial |
3701 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Enhanced stability of the square lattice of a classical bilayer Wigner crystal |
Type |
A1 Journal article |
Year |
1999 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
60 |
Issue |
|
Pages |
14665-14674 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Lancaster, Pa |
Editor |
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Language |
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Wos |
000084141700045 |
Publication Date |
2002-07-27 |
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 |
0163-1829;1095-3795; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.836 |
Times cited |
31 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 3.836; 1999 IF: NA |
Call Number |
UA @ lucian @ c:irua:27004 |
Serial |
1057 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Influence of the lattice symmetry on melting of the bilayer Wigner crystal |
Type |
A1 Journal article |
Year |
2000 |
Publication |
Journal de physique: 4
T2 – International Conference on Strongly Coupled Coulomb Systems, SEP 04-10, 1999, ST MALO, FRANCE |
Abbreviated Journal |
J Phys Iv |
Volume |
10 |
Issue |
P5 |
Pages |
117-120 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
The melting transition of the five different lattices of a bilayer crystal is studied using the Monte-Carlo (MC) technique. We found the surprising result that the square lattice has a substantial larger melting temperature as compared to the other lattice structures, which is a consequence of the specific topology of the temperature induced defects. A new melting criterion is formulated which we show to be universal for bilayers as well as for single layer crystals. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Les Ulis |
Editor |
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Language |
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Wos |
000087026300016 |
Publication Date |
2007-07-03 |
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 |
1155-4339; |
ISBN |
|
Additional Links |
UA library record; WoS full record |
Impact Factor |
|
Times cited |
|
Open Access |
|
Notes |
|
Approved |
Most recent IF: NA |
Call Number |
UA @ lucian @ c:irua:103954 |
Serial |
1647 |
Permanent link to this record |
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|
|
Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Melting of the classical bilayer Wigner crystal: influence of the lattice symmetry |
Type |
A1 Journal article |
Year |
1999 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
82 |
Issue |
|
Pages |
5293-5296 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
http://anet.uantwerpen.be/docman/irua/f3d874/7910.pdf |
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 |
|
Language |
|
Wos |
000081152700029 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
64 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 1999 IF: 6.095 |
Call Number |
UA @ lucian @ c:irua:24151 |
Serial |
1988 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Perturbation of collisional plasma flow around a charged dust particle: kinetic analysis |
Type |
A1 Journal article |
Year |
2005 |
Publication |
Physics of plasmas |
Abbreviated Journal |
Phys Plasmas |
Volume |
12 |
Issue |
11 |
Pages |
113501,1-9 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Woodbury, N.Y. |
Editor |
|
Language |
|
Wos |
000233569600046 |
Publication Date |
2005-11-07 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
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 |
15 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.115; 2005 IF: 2.182 |
Call Number |
UA @ lucian @ c:irua:56048 |
Serial |
2575 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Properties of two-dimensional Coulomb clusters confined in a ring |
Type |
A1 Journal article |
Year |
1996 |
Publication |
Physical review : B : condensed matter and materials physics |
Abbreviated Journal |
Phys Rev B |
Volume |
54 |
Issue |
|
Pages |
10827-10834 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
A1996VT67400087 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0163-1829;1095-3795; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
3.736 |
Times cited |
27 |
Open Access |
|
Notes |
|
Approved |
CHEMISTRY, PHYSICAL 77/144 Q3 # MATHEMATICS, INTERDISCIPLINARY 19/101 Q1 # PHYSICS, ATOMIC, MOLECULAR & CHEMICAL 17/35 Q2 # |
Call Number |
UA @ lucian @ c:irua:15791 |
Serial |
2730 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Radial fluctuations induced stabilization of the ordered state in two-dimensional classical clusters |
Type |
A1 Journal article |
Year |
2000 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
84 |
Issue |
|
Pages |
4381-4384 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
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Thesis |
|
Publisher |
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Place of Publication |
New York, N.Y. |
Editor |
|
Language |
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Wos |
000086941600032 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
69 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 2000 IF: 6.462 |
Call Number |
UA @ lucian @ c:irua:28518 |
Serial |
2807 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Schweigert, V.A.; Peeters, F.M. |
Title |
Reply to Rinn and Maass |
Type |
A1 Journal article |
Year |
2001 |
Publication |
Physical review letters |
Abbreviated Journal |
Phys Rev Lett |
Volume |
86 |
Issue |
20 |
Pages |
4712 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
|
Address |
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Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
New York, N.Y. |
Editor |
|
Language |
|
Wos |
000168623500075 |
Publication Date |
2002-07-27 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0031-9007;1079-7114; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
8.462 |
Times cited |
5 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 8.462; 2001 IF: 6.668 |
Call Number |
UA @ lucian @ c:irua:37308 |
Serial |
2877 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schweigert, I.V.; Alexandrov, A.L.; Ariskin, D.A.; Peeters, F.M.; Stefanović, I.; Kovačević, E.; Berndt, J.; Winter, J. |
Title |
Effect of transport of growing nanoparticles on capacitively coupled rf discharge dynamics |
Type |
A1 Journal article |
Year |
2008 |
Publication |
Physical review : E : statistical physics, plasmas, fluids, and related interdisciplinary topics |
Abbreviated Journal |
Phys Rev E |
Volume |
78 |
Issue |
2 |
Pages |
026410,1-026410,6 |
Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
Abstract |
We present experimental and numerical studies of the properties of a capacitively coupled 13.56 MHz discharge in a mixture of Ar and C2H2 with growing nanosize particles. It is found that at the initial stage of the growth, nanoparticles are accumulated near the sheath-plasma boundaries, where the ionization by electrons is maximal. The nanoparticles suppress the ionization due to the absorbing fast electrons and stimulate a quick change of the plasma parameters followed by a transition between different modes of discharge operation. At that moment the peaked distribution of the dust particles transforms into a flat one. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
|
Place of Publication |
Lancaster, Pa |
Editor |
|
Language |
|
Wos |
000259263700071 |
Publication Date |
2008-08-20 |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1539-3755;1550-2376; |
ISBN |
|
Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
2.366 |
Times cited |
36 |
Open Access |
|
Notes |
|
Approved |
Most recent IF: 2.366; 2008 IF: 2.508 |
Call Number |
UA @ lucian @ c:irua:76552 |
Serial |
851 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schutyser, W.; Van den Bosch, S.; Dijkmans, J.; Turner, S.; Meledina, M.; Van Tendeloo, G.; Debecker, D.P.; Sels, B.F. |
Title |
Selective nickel-catalyzed conversion of model and lignin-derived phenolic compounds to cyclohexanone-based polymer building blocks |
Type |
A1 Journal article |
Year |
2015 |
Publication |
Chemsuschem |
Abbreviated Journal |
Chemsuschem |
Volume |
8 |
Issue |
8 |
Pages |
1805-1818 |
Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
Abstract |
Valorization of lignin is essential for the economics of future lignocellulosic biorefineries. Lignin is converted into novel polymer building blocks through four steps: catalytic hydroprocessing of softwood to form 4-alkylguaiacols, their conversion into 4-alkylcyclohexanols, followed by dehydrogenation to form cyclohexanones, and Baeyer-Villiger oxidation to give caprolactones. The formation of alkylated cyclohexanols is one of the most difficult steps in the series. A liquid-phase process in the presence of nickel on CeO2 or ZrO2 catalysts is demonstrated herein to give the highest cyclohexanol yields. The catalytic reaction with 4-alkylguaiacols follows two parallel pathways with comparable rates: 1) ring hydrogenation with the formation of the corresponding alkylated 2-methoxycyclohexanol, and 2) demethoxylation to form 4-alkylphenol. Although subsequent phenol to cyclohexanol conversion is fast, the rate is limited for the removal of the methoxy group from 2-methoxycyclohexanol. Overall, this last reaction is the rate-limiting step and requires a sufficient temperature (> 250 degrees C) to overcome the energy barrier. Substrate reactivity (with respect to the type of alkyl chain) and details of the catalyst properties (nickel loading and nickel particle size) on the reaction rates are reported in detail for the Ni/CeO2 catalyst. The best Ni/CeO2 catalyst reaches 4-alkylcyclohexanol yields over 80 %, is even able to convert real softwood-derived guaiacol mixtures and can be reused in subsequent experiments. A proof of principle of the projected cascade conversion of lignocellulose feedstock entirely into caprolactone is demonstrated by using Cu/ZrO2 for the dehydrogenation step to produce the resultant cyclohexanones (approximate to 80%) and tin-containing beta zeolite to form 4-alkyl-e-caprolactones in high yields, according to a Baeyer-Villiger-type oxidation with H2O2. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Weinheim |
Editor |
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Language |
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Wos |
000355220300020 |
Publication Date |
2015-04-16 |
Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1864-5631; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.226 |
Times cited |
71 |
Open Access |
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Notes |
Fwo |
Approved |
Most recent IF: 7.226; 2015 IF: 7.657 |
Call Number |
c:irua:126406 |
Serial |
2967 |
Permanent link to this record |
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Author ![sorted by Author field, descending order (down)](img/sort_desc.gif) |
Schütte, K.; Doddi, A.; Kroll, C.; Meyer, H.; Wiktor, C.; Gemel, C.; Van Tendeloo, G.; Fischer, R.A.; Janiak, C. |
Title |
Colloidal nickel/gallium nanoalloys obtained from organometallic precursors in conventional organic solvents and in ionic liquids : noble-metal-free alkyne semihydrogenation catalysts |
Type |
A1 Journal article |
Year |
2014 |
Publication |
Nanoscale |
Abbreviated Journal |
Nanoscale |
Volume |
6 |
Issue |
10 |
Pages |
5532-5544 |
Keywords |
A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT) |
Abstract |
Efforts to replace noble-metal catalysts by low-cost alternatives are of constant interest. The organometallic, non-aqueous wet-chemical synthesis of various hitherto unknown nanocrystalline Ni/Ga intermetallic materials and the use of NiGa for the selective semihydrogenation of alkynes to alkenes are reported. Thermal co-hydrogenolysis of the all-hydrocarbon precursors [Ni(COD)(2)] (COD = 1,5-cyclooctadiene) and GaCp* (Cp* = pentamethylcyclopentadienyl) in high-boiling organic solvents mesitylene and n-decane in molar ratios of 1 : 1, 2 : 3 and 3 : 1 yields the nano-crystalline powder materials of the over-all compositions NiGa, Ni2Ga3 and Ni3Ga, respectively. Microwave induced co-pyrolysis of the same precursors without additional hydrogen in the ionic liquid [BMIm][BF4] (BMIm = 1-butyl-3-methyl-imidazolium) selectively yields the intermetallic phases NiGa and Ni3Ga from the respective 1 : 1 and 3 : 1 molar ratios of the precursors. The obtained materials are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), IR, powder X-ray diffraction (PXRD) and atomic absorption spectroscopy (AAS). The single-source precursor [Ni(GaCp*)(PMe3)(3)] with a fixed Ni : Ga stoichiometry of 1 : 1 was employed as well. In comparison with the co-hydrogenolytic dual precursor source approach it turned out to be less practical due to inefficient nickel incorporation caused by the parasitic formation of stable [Ni(PMe3)(4)]. The use of ionic liquid [BMIm][BF4] as a non-conventional solvent to control the reaction and stabilize the nanoparticles proved to be particularly advantageous and stable colloids of the nanoalloys NiGa and Ni3Ga were obtained. A phase-selective Ni/Ga colloid synthesis in conventional solvents and in the presence of surfactants such as hexadecylamine (HDA) was not feasible due to the undesired reactivity of HDA with GaCp* leading to inefficient gallium incorporation. Recyclable NiGa nanoparticles selectively semihydrogenate 1-octyne and diphenylacetylene (tolan) to 1-octene and diphenylethylene, respectively, with a yield of about 90% and selectivities of up to 94 and 87%. Ni-NPs yield alkanes with a selectivity of 97 or 78%, respectively, under the same conditions. |
Address |
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Corporate Author |
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Thesis |
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Publisher |
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Place of Publication |
Cambridge |
Editor |
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Language |
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Wos |
000335148800069 |
Publication Date |
2014-03-06 |
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 |
2040-3364;2040-3372; |
ISBN |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
Impact Factor |
7.367 |
Times cited |
40 |
Open Access |
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Notes |
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Approved |
Most recent IF: 7.367; 2014 IF: 7.394 |
Call Number |
UA @ lucian @ c:irua:117251 |
Serial |
390 |
Permanent link to this record |