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1. Aqueous Precursor Systems

Author

Van Bael, Marlies K., Hardy, An, Mullens, Jules, Schneller, Theodor, editor, Waser, Rainer, editor, Kosec, Marija, editor, and Payne, David, editor

Published
2013
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11. Alternative Gate Dielectric Materials

Author

Van Elshocht, Sven, primary, Hardy, An, additional, De Gendt, S., additional, Adelmann, Christophe, additional, Baumann, Peter K., additional, Brunco, David P., additional, Caymax, Matty R., additional, Conard, Thierry, additional, Delugas, Pietro, additional, Lehnen, Peer, additional, Richard, Olivier, additional, Rohr, Erika, additional, Shamiryan, Denis, additional, Vos, Rita, additional, Witters, Thomas, additional, Zimmerman, Paul, additional, Van Bael, Marlies K., additional, Mullens, Jules, additional, Meuris, Marc M., additional, and Heyns, Marc M., additional

Published
2019
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15. Monte Carlo analysis of error propagation in the potentiometric determination of equilibrium constants

Author

GUEDENS, Wanda, MULLENS, Jules, and VAN POUCKE, Lucien

Subjects
Monte Carlo simulation, error propagation, potentiometric, equilibrium constant
Abstract

The calculation of formation constants of metal complexes is an important and active area of modern solution chemistry. The precision with which these constants are calculated can be quantified by a Monte Carlo technique from realistic estimates of the experimental errors in (potentiometric) titration parameters. Moreover, having better estimates of the standard deviations, this capability of Monte Carlo analysis has potential implications for model selection. A Matlab® program suite has been developed in order to quantify the statistical uncertainty on the optimized stability constants in complex models. The suite consists of a data generation program and a refinement program. The free concentrations of the individual components in the model are obtained by iteratively solving the set of non-linear mass balance equations using Newton’s method. The core of the refinement algorithm is a Gauss-Newton minimization of a sum of weighted squared residuals in electrode potential based on implicit differentiation (see also the standard program SuperQuad in Fortran 77). The present work shows a detailed error analysis in the determination of stability constants that is rarely done. Analysis of simulated data demonstrates that in certain cases the risk of accepting a false model is real! Verification of residual plots shows that the 2 test is the least convincing and most controversial criterion for model selection. In addition, we have formulated some new criteria to increase the reliability of potentiometric data.

Published
2000

20. Crystallization resistance of barium titanate zirconate ultrathin films from aqueous CSD: a study of cause and effect

Author

Hardy, An, primary, Van Elshocht, Sven, additional, Knaepen, Werner, additional, D'Haen, Jan, additional, Conard, Thierry, additional, Brijs, Bert, additional, Vandervorst, Wilfred, additional, Pourtois, Geoffrey, additional, Kittl, Jorge, additional, Detavernier, Christophe, additional, Heyns, Marc, additional, Van Bael, Marlies K., additional, Van den Rul, Heidi, additional, and Mullens, Jules, additional

Published
2009
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39. Alternative Gate Dielectric Materials

Author

Van, Sven, Hardy, An, Gendt, De, Adelmann, Christophe, Baumann, Peter K., Brunco, David P., Caymax, Matty R., Conard, Thierry, Delugas, Pietro, Lehnen, Peer, Richard, Olivier, Rohr, Erika, Shamiryan, Denis, Vos, Rita, Witters, Thomas, Zimmerman, Paul, Van, Marlies K., Mullens, Jules, Meuris, Marc M., and Heyns, Marc M.

Abstract

Alternative high-k materials are being researched as a replacement for SiON. At present HfSiON is the most popular material because of good transistor performance. Still, issues such as threshold voltage control and a limited k-value improvement encourage continuing material screening. In this paper, we give a short overview of some of the work done in this field, where we focus on DyxSc2-xO3 as potential candidate. In addition, we discuss the use of the aqueous chemical solution-gel deposition technique as potential technique to facilitate high-k screening.

Published
2006

40. Water-based wet chemical synthesis of (doped) ZnO nanostructures

Author

Rul, Heidi, Mondelaers, Dirk, Bael, Marlies, and Mullens, Jules

Abstract

Looking at its vast range of applications, nanostructured ZnO can be considered as a key technological material. Simple and ecological production techniques for this and other nanostructured materials can boost the detection of their unusual properties. In this context water-based wet chemical synthesis routes for nanostructured ZnO are explored in this study. The advantages and disadvantages of controlled double-jet precipitation, microemulsion preparation, hydrothermal synthesis and an aqueous solution-gel route are described for the formation of (doped) ZnO nanoparticles. The influence of the synthesis parameters on the particle size, size distribution and degree of agglomeration of the particles is reported. Thin films are prepared by chemical solution deposition from aqueous solution. The heat treatment profile and the precursor composition are seen to largely control the density, the grain size and the degree of preferential c-axis orientation.Looking at its vast range of applications, nanostructured ZnO can be considered as a key technological material. Simple and ecological production techniques for this and other nanostructured materials can boost the detection of their unusual properties. In this context water-based wet chemical synthesis routes for nanostructured ZnO are explored in this study. The advantages and disadvantages of controlled double-jet precipitation, microemulsion preparation, hydrothermal synthesis and an aqueous solution-gel route are described for the formation of (doped) ZnO nanoparticles. The influence of the synthesis parameters on the particle size, size distribution and degree of agglomeration of the particles is reported. Thin films are prepared by chemical solution deposition from aqueous solution. The heat treatment profile and the precursor composition are seen to largely control the density, the grain size and the degree of preferential c-axis orientation.

Published
2006
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41. Phase formation of ferroelectric perovskite 0.75 Pb(Zn<SUB>1/3</SUB>,Nb<SUB>2/3</SUB>)O<SUB>3</SUB>–0.25 BaTiO<SUB>3</SUB> prepared by aqueous solution–gel chemistry

Author

Werde, Kristof Van, Vanhoyland, Geert, Nelis, Daniël, Mondelaers, Dirk, Bael, Marlies K. Van, Mullens, Jules, and Poucke, Lucien C. Van

Abstract

Here we report on the synthesis and phase formation of perovskite 0.75 Pb(Zn1/3,Nb2/3)O3–0.25 BaTiO3 (PZN–BT) by means of a new aqueous solution–gel method. The gelation process was optimized for an ammonium PZN acetate citrate precursor. The chemical homogeneity of this precursor was investigated by means of TEM–EDX analysis (Transmission Electron Microscopy–Energy Dispersive X-ray analysis). All metal ions were found to be homogeneously dispersed in the precursor gel at least down to 10 nm. An aqueous BaTiO3 precursor was synthesized and its oxide formation was investigated by means of HT-XRD (High Temperature X-ray Diffraction) and TGA–MS (Thermogravimetric Analysis on-line coupled to Mass Spectrometry). The gel-to-oxide transition of the PZN–BT precursor was studied using HT-XRD and TGA–MS. It was concluded that 96+ weight% perovskite PZN–BT could be formed out of the gel precursor if proper thermal treatment is applied (14 minutes sintering at 800 °C after fast firing at 50 °C min−1). Finally a phase formation mechanism for perovskite PZN–BT is proposed: perovskite 0.75 Pb(Zn1/3,Nb2/3)O3–0.25 BaTiO3 is formed out of a cubic pyrochlore PZN. At 850 °C the perovskite decomposes irreversibly into that same pyrochlore together with volatile PbO and ZnO. The evolution of PbO was proved with TGA.

Published
2001

42. Nanoparticles of γ-Al2O3 as perspective fillers of thermoplastic polymers improving their barrier properties.

Author

Lepot, Nadia, Van Bael, Marlies K., Van Den Rul, Heidi, Peeters, Roos, Mullens, Jules, and Franco, Dirk

Subjects
NANOPARTICLES, ALUMINUM oxide, MORPHOLOGY, POLYMERS, PARTICLES
Abstract

Copyright of Polimery is the property of Industrial Chemistry Research Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2006
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43. Automated iodimetric determination of Cu+, Cu2+and Cu3+in the superconductor YBCO using a modified Gran plot technique

Author

Yperman, Jan, De Backer, An, Vos, Ann, Franco, Dirk, Mullens, Jules, and Van Poucke, Lucien C.

Abstract

An automated potentiometric determination of the oxygen content of the superconductor YBCO is described. The end- point of the titration is found using a linear Gran plot technique. Suitable equations are derived by which the number of titration points can be considerably reduced and the titration can be stopped even before the equivalence point is reached. Automation of the iodimetric titration can be performed in an easy manner. During the titration a good estimate of the equivalence volume can be calculated using only two titration points.

Published
1993
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50. A statistical approach to the identification of determinant factors in the preparation of phase pure (Bi,La)4Ti3O12 from an aqueous citrate gel

Author

Hardy, An, Vanhoyland, Geert, Van Bael, Marlies, Mullens, Jules, and Van Poucke, Lucien

Subjects
*CRYSTALLIZATION, *PEROVSKITE, *LANTHANUM, *BISMUTH, *TITANIUM dioxide, *STOICHIOMETRY
Abstract

The factors influencing crystallization of layered-perovskite lanthanum substituted bismuth titanate, starting from an aqueous metal-chelate precursor-gel, were identified by means of statistically designed experiments. To ensure experimental economy and efficiency in spite of the large number of factors possibly affecting the phase purity, a fractional factorial design was chosen. The calcination atmosphere turned out to be the most important to avoid the formation of the Sillenite secondary phase, Bi12TiO20. In order to study its impact on phase purity thoroughly an extensive number of ambient compositions were tested. These tests showed that dry air is the optimal composition. Precursor stoichiometry and gas flow rate during heat treatment also significantly influenced the formation of Bi12TiO20. Furthermore, the precursor stoichiometry and cooling rate as well as the calcination atmosphere and crystallization time turned out to interact. [Copyright &y& Elsevier]

Published
2004
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