Searched for: subject:"permittivity"
(1 - 20 of 30)

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van der Lingen, Elisabeth (author)
Due to the earth’s population growth and the increased living age of a person, more and more people could deal with medical problems. Early detection of health related problems in both healthy and people with medical problems, will catch problems early and prevent the need for more costly procedures. One of these medical problems is concerning...
master thesis 2020
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Adla, Soham (author), Rai, Neeraj Kumar (author), Karumanchi, Sri Harsha (author), Tripathi, Shivam (author), Disse, Markus (author), Pande, S. (author)
Soil volumetric water content (VWC) is a vital parameter to understand several ecohydrological and environmental processes. Its cost-effective measurement can potentially drive various technological tools to promote data-driven sustainable agriculture through supplemental irrigation solutions, the lack of which has contributed to severe...
journal article 2020
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van Gemert, J.H.F. (author)
This dissertation describes how to design dielectric pads that can be used to increase image quality in Magnetic Resonance Imaging, and how to accelerate image reconstruction times using a preconditioner.<br/><br/>Image quality is limited by the signal to noise ratio of a scan. This ratio is increased for higher static magnetic field strengths...
doctoral thesis 2019
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van Gemert, Jeroen (author), Brink, Wyger (author), Webb, A. (author), Remis, R.F. (author)
Purpose: High-permittivity materials in the form of flexible “dielectric pads” have proved very useful for addressing RF inhomogeneities in high field MRI systems. Finding the optimal design of such pads is, however, a tedious task, reducing the impact of this technique. We present an easy-to-use software tool which allows researchers and...
journal article 2019
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Leijsen, R.L. (author), van den Berg, Cornelis (author), Webb, A. (author), Remis, R.F. (author), Mandija, Stefano (author)
Magnetic resonance electrical properties tomography (MR-EPT) is a technique used to estimate the conductivity and permittivity of tissues from MR measurements of the transmit magnetic field. Different reconstruction methods are available; however, all these methods present several limitations, which hamper the clinical applicability. Standard...
journal article 2019
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van Gemert, J.H.F. (author), Brink, Wyger M. (author), Remis, R.F. (author), Webb, A. (author)
PURPOSE: One of the main concerns in fetal MRI is the radiofrequency power that is absorbed both by the mother and the fetus. Passive shimming using high permittivity materials in the form of "dielectric pads" has previously been shown to increase the formula presented efficiency and homogeneity in different applications, while reducing the...
journal article 2019
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van Gemert, J.H.F. (author), Brink, W.M. (author), Webb, A. (author), Remis, R.F. (author)
Inhomogeneities in the transmit radio frequency magnetic field ( {\text{B}}-{1}^{+} ) reduce the quality of magnetic resonance (MR) images. This quality can be improved by using high-permittivity pads that tailor the {\text{B}}-{1}^{+} fields. The design of an optimal pad is application-specific and not straightforward and would therefore...
journal article 2018
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Vlachogiannakis, G. (author), Pertijs, M.A.P. (author), Spirito, M. (author), de Vreede, L.C.N. (author)
A compact sensing pixel for the determination of the localized complex permittivity at microwave frequencies is proposed. Implemented in the 40-nm CMOS, the architecture comprises a square patch, interfaced to the material-under-test sample, that provides permittivity-dependent admittance. The patch admittance is read out by embedding the patch...
journal article 2018
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Hu, Z. (author), Vlachogiannakis, G. (author), Pertijs, M.A.P. (author), de Vreede, L.C.N. (author), Spirito, M. (author)
A 0.14-μ m CMOS 2-D permittivity imaging matrix prototype operating at microwave frequencies is presented. It comprises 25 permittivity-sensing pixels, each consisting of a sensing patch connected to a dedicated RF bridge. A trans-conduct-ance stage converts the imbalance voltage to a current signal, subsequently down-converted to an...
conference paper 2018
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Marx, Philipp (author), Wanner, Andrea (author), Zhang, Zucong (author), Jin, H. (author), Tsekmes, I.A. (author), Smit, J.J. (author), Kern, Wolfgang (author), Wiesbrock, Frank (author)
Five types of nanofillers, namely, silica, surface-silylated silica, alumina, surface-silylated alumina, and boron nitride, were tested in this study. Nanocomposites composed of an epoxy/amine resin and one of the five types of nanoparticles were tested as dielectrics with a focus on (i) the surface functionalization of the nanoparticles and (ii...
contribution to periodical 2017
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Cavallo, Daniele (author), Cantika Felita, Cantika (author)
We present an analysis of artificial dielectric layers (ADLs), when a lateral shift between layers is present. The alternate lateral displacement of the layers is an important parameter to engineer the desired effective electromagnetic properties of the ADL material. More specifically, much higher equivalent dielectric constants can be...
conference paper 2017
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Kremers, A. (author), Truong, M.H. (author)
As a part of the development of a device for skin cancer tissue detection, this report is about the development of a new calibration procedure for measuring complex permittivity with an open-ended coaxial probe. The developed method is based on comparing the measured reflection coefficient to an array of reference coefficients for different...
bachelor thesis 2016
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Peksa, A.E. (author), Wolf, K.H.A.A. (author), Slob, E.C. (author), Chmura, L.A. (author), Zitha, P.L.J. (author)
Bentheimer sandstone is a quartz-rich permeable hard sedimentary rock used for core flooding experiments. When fired to stabilize clays (subjected to high temperatures), pyrometamorphical phase changes induce texture and pore framework alteration. As a consequence the new dielectric response may influence wettability. The literature regarding...
journal article 2016
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Chassagne, C. (author), Dubois, Emmanuelle (author), Jiménez, María L. (author), Ploeg, J.C. (author), van Turnhout, J. (author)
Dielectric spectroscopy can be used to determine the dipole moment of colloidal particles from which important interfacial electrokinetic properties, for instance their zeta potential, can be deduced. Unfortunately, dielectric spectroscopy measurements are hampered by electrode polarization (EP). In this article, we review several procedures...
journal article 2016
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Fimberger, M. (author), Tsekmes, I.A. (author), Kochetov, R. (author), Smit, J.J. (author), Wiesbrock, F. (author)
Poly(2-nonyl-2-oxazoline)80-stat-poly(2-dec-9?-enyl-2-oxazoline)20 and poly(2-dec-9?-enyl-2-oxazoline)100 can be synthesized from the cationic ring-opening polymerization of monomers that can be derived from fatty acids from renewable resources. These (co)poly(2-oxazoline)s can be crosslinked with di- and trifunctional mercapto compounds using...
journal article 2015
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Hassan, A.M. (author)
Characterization of fluid properties is significant in the petroleum engineering practice, especially in solvent-based enhanced oil recovery (SEOR) where the use of injected chemicals should ideally be reduced to the bare minimum in order to minimize the costs and environmental impact of SEOR. However, current techniques for measurement inside...
master thesis 2015
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Alonso Del Pino, M. (author), Cavallo, D. (author), Thippur Shivamurthy, H. (author), Gao, H. (author), Spirito, M. (author)
This contribution presents the development of an integrated power combiner in Bi-CMOS technology employing artificial dielectric layers (ADLs) at submillimeter wave frequencies. The power is gathered from frequency multiplier chains into a single waveguide which is loaded with ADL in order to reduce the structure footprint.
conference paper 2015
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Koolstra, K. (author)
Modeling electromagnetic fields in MRI involves two main challenges: the solution of the scattering problem resulting from Maxwell's equations has to be accurate and it has to be obtained within short computation time. In this thesis a method that meets both requirements is searched for. The method of moments with rooftop basis functions is used...
master thesis 2015
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Van den Ende, D.A. (author), Maier, R.A. (author), Van Neer, P.L.M.J. (author), Van der Zwaag, S. (author), Randall, C.A. (author), Groen, W.A. (author)
In this work, the piezoelectric properties at high electric fields of dielectrophoretically aligned PZT—polymer composites containing high aspect ratio particles (such as short fibers) are presented. Polarization and strain as a function of electric field are evaluated. The properties of the composites are compared to those of PZT-polymer...
journal article 2013
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Van den Ende, D.A. (author), Van Kempen, S.E. (author), Wu, X. (author), Groen, W.A. (author), Randall, C.A. (author), Van der Zwaag, S. (author)
Piezoelectric composites were prepared by dielectrophoretic alignment of high aspect ratio piezoelectric particles in a thermosetting polymer matrix. A high level of alignment was achieved in the cured composite from a resin containing randomly oriented high aspect ratio particles. Upon application of an electric field during curing of the resin...
journal article 2012
Searched for: subject:"permittivity"
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