ir. J.W. de Vries

Biomedical Signal Processing

Binaural speech enhancement

1. Binaural Beamforming Taking into Account Spatial Release from Masking
   Johannes W. de Vries; Steven van de Par; Geert Leus; Richard Heusdens; Richard C. Hendriks;
   Trans. Audio, Speech and Language Processing, 2024.,
   2024. Additional material: software

2. A Comparison of Methods for Fiber Direction Estimation from Electrograms
   Elena van Breukelen; Johannes Willem de Vries; Mathijs van schie; Natasja de Groot; Richard C. Hendriks;
   In 2024 Computing in Cardiology (CinC),
   2024.

3. Estimation of Cardiac Fibre Direction Based on Activation Maps
   J. W. de Vries; M. Sun; N. M. S. de Groot; R. C. Hendriks;
   In IEEE International Conference on Acoustics, Speech, and Signal Processing (ICASSP),
   2023. Additional material: software • software

4. Optical ventricular cardioversion by local optogenetic targeting and LED implantation in a cardiomyopathic rat model
   Emile C. A. Nyns; Tianyi Jin; Magda S Fontes; Titus van den Heuvel; Vincent Portero; Catilin Ramsey; Cindy I. Bart; Katja Zeppenfeld; Martin J. Schalij; Thomas J. van Brakel; Arti A. Ramkisoensing; GuoQi Zhang; René H. Poelma; Balazs Ördög; Antoine A. F. de Vries; Daniël A. Pijnappels;
   Cardiovascular Research,
   September 2021. DOI: 10.1093/cvr/cvab294

5. Continuous shock-free termination of atrial fibrillation by local optogenetic therapy and arrhythmia-triggered activation of an implanted light source
   E C A Nyns; R H Poelma; L Volkers; C I Bart; T J Van Brakel; K Zeppenfeld; M J Schalij; GuoQi Zhang; A A F De Vries; D A Pijnappels;
   European Heart Journal,
   Volume 40, Issue 1, 2019. DOI: 10.1093/eurheartj/ehz748.0090

6. An automated hybrid bioelectronic system for autogenous restoration of sinus rhythm in atrial fibrillation
   Emile C. A. Nyns; René H. Poelma; Linda Volkers; Jaap J. Plomp; Cindy I. Bart; Annemarie M. Kip; Thomas J. van Brakel; Katja Zeppenfeld; Martin J. Schalij; GuoQi Zhang; Antoine A. F. de Vries; Daniël A. Pijnappels;
   Science Translational Medicine,
   Volume 11, Issue 481, 2019. DOI: 10.1126/scitranslmed.aau6447

7. Temperature dependence of the energy barrier and switching field of sub-micron magnetic islands with perpendicular anisotropy
   Vries, Jeroen De; Bolhuis, Thijs; Abelmann, Leon;
   New Journal of Physics,
   Volume 19, Issue 9, 2017. All Open Access, Gold Open Access, Green Open Access. DOI: 10.1088/1367-2630/aa8082
   
   Keywords: ...

   Anisotropy; Chemical activation; Energy barriers; Extrapolation; Magnetic materials; Magnetism; Temperature distribution; Anomalous hall effects; Magnetic elements; Magnetic reversal; Perpendicular anisotropy; Switching field distribution; Temperature dependence; Temperature dependent; Temperature-dependent measurements; Switching.
   
   
   Abstract: ...

   Using the highly sensitive anomalous Hall effect we have been able to measure the reversal of a single magnetic island, of diameter 220 nm, in an array consisting of more than 80 of those islands. By repeatedly traversing the hysteresis loop, we measured the thermally induced fluctuation of the switching field of the islands at the lower and higher ends of the switching field distribution. Based on a novel easy-to-use model, we determined the switching field in the absence of thermal activation, and the energy barrier in the absence of an external field from these fluctuations. By measuring the reversal of individual dots in the array as a function of temperature, we extrapolated the switching field and energy barrier down to 0 K. The extrapolated values are not identical to those obtained from the fluctation of the switching field at room temperature, because the properties of the magnetic material are temperature dependent. As a result, extrapolating from temperature dependent measurements overestimates the energy barrier by more than a factor of two. To determine fundamental parameters of the energy barrier between magnetisation states, measuring the fluctuation of the reversal field at the temperature of application is therefore to be preferred. This is of primary importance to applications in data storagea and magnetic logic. For instance in fast switching, where the switching field in the absence of thermal activation plays a major role, or in long term data stability, which is determined by the energy barrier in the absence of an external field. © 2017 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.
   
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8. Ultra-flat bismuth films for diamagnetic levitation by template-stripping
   Kokorian, J.; Engelen, J. B. C.; De Vries, J.; Nazeer, H.; Woldering, L. A.; Abelmann, L.;
   Thin Solid Films,
   Volume 550, pp. 298 – 304, 2014. All Open Access, Green Open Access. DOI: 10.1016/j.tsf.2013.11.074
   
   Keywords: ...

   Atomic force microscopy; Crystal structure; Deposition; Elastic moduli; Surface roughness; X ray diffraction; Average surface roughness; C-axis orientations; Diamagnetic levitation; Peak-to-peak values; Polycrystalline textures; Template stripping; X-ray diffraction measurements; Young's Modulus; Bismuth.
   
   
   Abstract: ...

   In this paper we present a method to deposit thin films of bismuth with sub-nanometer surface roughness for application to diamagnetic levitation. Evaporated films of bismuth have a high surface roughness with peak to peak values in excess of 100 nm and average values on the order of 20 nm. We expose the smooth backside of the films using a template stripping method, resulting in a great reduction of the average surface roughness, to 0.8 nm. Atomic force microscope and X-ray diffraction measurements show that the films have a polycrystalline texture with preferential c-axis orientation. On the back side of the film, fine grains are grouped into larger clusters. Cantilever resonance shift measurements indicate that the Young's modulus of the films is on the order of 20 GPa. © 2013 Elsevier B.V.
   
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9. Energy barrier versus switching field for patterned Co80Pt 20 alloy and Co/Pt multilayer films
   de Vries, Jeroen; Bolhuis, Thijs; Abelmann, Leon;
   Journal of Applied Physics,
   Volume 113, Issue 17, 2013. DOI: 10.1063/1.4801399
   
   Keywords: ...

   Alloys; Energy barriers; Magnetic materials; Multilayer films; Multilayers; Anomalous hall effects; Co/Pt multilayer; Ion beam etching; Laser interference lithography; Magnetic island; Magnetic layers; Switching field distribution; Thermal switching; Switching.
   
   
   Abstract: ...

   Two Co/Pt multilayer samples have been fabricated with a difference in the number of bilayers, leading to a total magnetic layer thickness of 3 nm and 20 nm. From these films, large arrays of magnetic islands have been patterned using laser interference lithography and ion beam etching. We have investigated the switching field distribution (SFD) of approximately 80 islands and thermal switching field distribution SFDT of individual islands of both samples using the anomalous Hall effect. We compare the results of these measurements with the (SFDT) of a previously investigated alloy with a magnetic layer thickness of 20 nm by comparing the results of over 1000 hysteresis loops of a single weak island and a single strong island. We found that that the energy barrier for the multilayer islands increases with increasing switching field, whereas it was previously found that the energy barrier for the alloy stays constant with varying switching fields. When comparing the two multilayer samples, we observe that the grain size, anisotropy, and switching field distribution are more or less independent on thickness, whereas the switching field at both 0 K and 300 K decreases with film thickness. © 2013 AIP Publishing LLC.
   
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10. Determination of bit patterned media noise based on island perimeter fluctuations
    Alink, Laurens; Groenland, J. P. J.; De Vries, Jeroen; Abelmann, Leon;
    IEEE Transactions on Magnetics,
    Volume 48, Issue 11, pp. 4574 – 4577, 2012. All Open Access, Green Open Access. DOI: 10.1109/TMAG.2012.2201138
    
    Keywords: ...

    Fourier series; Bit-patterned media; Channel modeling; Fourier-series expansion; High density; Jitter noise; Laser interference lithography; Magnetic island; Media noise; Model-based OPC; Jitter.
    
    
    Abstract: ...

    We measured the fluctuation in shape of magnetic islands in bit patterned media fabricated by laser interference lithography. This fluctuation can be accurately described by a model based on a Fourier series expansion of the perimeter of the islands. The model can be easily linked to amplitude and jitter noise. We show that the amplitude and jitter noise are in principle correlated, and the jitter noise increases with increasing island area. The correlation is small for media prepared by laser interference lithography, but expected to gain importance for high density bit patterned media. © 1965-2012 IEEE.
    
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11. Measurement of the nucleation and domain depinning field in a single Co/Pt multilayer dot by Anomalous Hall effect
    Delalande, M.; De Vries, J.; Abelmann, L.; Lodder, J. C.;
    Journal of Magnetism and Magnetic Materials,
    Volume 324, Issue 7, pp. 1277 – 1280, 2012. All Open Access, Green Open Access. DOI: 10.1016/j.jmmm.2011.09.037
    
    Keywords: ...

    Hall effect; Magnetic storage; Multilayers; Nucleation; Angular dependence; Anomalous Hall effects; Co/Pt multilayer; Depinning; Depinning fields; Domain nucleation; Easy axis; In-plane; Magnetic reversal; Nucleation field; Perpendicular anisotropy; Separate analysis; Magnetic domains.
    
    
    Abstract: ...

    Co/Pt multilayer dots with perpendicular anisotropy and with diameters of 250 and 350 nm were fabricated on top of a Hall cross configuration. The angular dependence of the magnetic reversal of the individual dot was investigated by Anomalous Hall effect measurements. At near in-plane angles (85° with the magnetic easy axis) the dot switches partially into a stable two-domain state. This allows for separate analysis of the angular dependence of both the field required for nucleation of a reversed domain, and the field required for depinning of the domain wall. The angular dependence of the depinning field fits accurately to a 1/cos(θ) behavior, whereas the angular dependence of the nucleation field shows a minimum close to 45°. The latter dependency can be accurately fitted to the modified Kondorsky model proposed by Schumacher [1]. © 2011 Elsevier B.V. All rights reserved.
    
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12. Image-based magnetic control of paramagnetic microparticles in water
    Keuning, Jasper D.; De Vries, Jeroen; Abelmann, Leon; Misra, Sarthak;
    conference, 2011. All Open Access, Green Open Access. DOI: 10.1109/IROS.2011.6048703
    
    Keywords: ...

    Finite element method; Intelligent robots; Machine design; Magnetic moments; Paramagnetic materials; Paramagnetism; Position control; Average diameter; Finite element method simulation; Image-based; Magnetic behavior; Magnetic control; Microscopic image; Paramagnetic microparticles; Vibrating sample magnetometer; Robotics.
    
    
    Abstract: ...

    This paper describes the design of a system for controlling the position of spherical paramagnetic microparticles that have an average diameter of 100 μm. The focus of this study lies in designing and implementing a system that uses microscopic images and electromagnets. Preliminary experiments have been done to verify the feasibility of the system to track and control the position of these particles. A vibrating sample magnetometer was used to determine the magnetic moment of the particles. Finite element method simulations were used to verify the magnetic behavior of the designed setup. The system was used to position the particles within 8.4μm of a setpoint, achieving speeds of up to 235μm s -1. We also demonstrated that the particle could follow a circular and a figure-eight path. © 2011 IEEE.
    
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13. Fatigue model based on average cross-section strain of Cu trace cyclic bending
    D.M. Farley; A. Dasgupta; Y. Zhou; J.F.J Caers; J.W.C. de Vries;
    In 12th Internat. Conf. on Thermal, Mechanical and Multi-Physics Simulation and Experiments Microelectronics and Microsystems (EuroSimE 2011),
    Linz, Austria, pp. 1-10, Apr. 2011. ISBN 978-1-4577-0106-1; DOI 10.1109/ESIME.2011.5765858.

14. Parallel optical readout of cantilever arrays in dynamic mode
    Koelmans, W. W.; Van Honschoten, J.; De Vries, J.; Vettiger, P.; Abelmann, L.; Elwenspoek, M. C.;
    Nanotechnology,
    Volume 21, Issue 39, 2010. All Open Access, Green Open Access. DOI: 10.1088/0957-4484/21/39/395503
    
    Keywords: ...

    Electromagnetic Fields; Interferometry; Lab-On-A-Chip Devices; Nanotechnology; Optics and Photonics; Atomic force microscopy; Bandwidth; Natural frequencies; Array of cantilevers; Available bandwidth; Beam deflection; Biological sensing; Cantilever arrays; Data storage; Diode pairs; Dynamic modes; Multi frequency; Nano scale; Nanomechanical response; Optical beam deflection; Optical readout; Probe-based; Quality factors; Received signals; Resonant frequencies; Single lasers; article; electromagnetic field; instrumentation; interferometry; lab on a chip; methodology; nanotechnology; optics; Nanocantilevers.
    
    
    Abstract: ...

    Parallel frequency readout of an array of cantilevers is demonstrated using optical beam deflection with a single laser-diode pair. Multi-frequency addressing makes the individual nanomechanical response of each cantilever distinguishable within the received signal. Addressing is accomplished by exciting the array with the sum of all cantilever resonant frequencies. This technique requires considerably less hardware compared to other parallel optical readout techniques. Readout is demonstrated in beam deflection mode and interference mode. Many cantilevers can be readout in parallel, limited by the oscillators' quality factor and available bandwidth. The proposed technique facilitates parallelism in applications at the nano-scale, including probe-based data storage and biological sensing. © 2010 IOP Publishing Ltd.
    
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15. Spatial sensitivity mapping of Hall crosses using patterned magnetic nanostructures
    Alexandrou, M.; Nutter, P. W.; Delalande, M.; De Vries, J.; Hill, E. W.; Schedin, F.; Abelmann, L.; Thomson, T.;
    Journal of Applied Physics,
    Volume 108, Issue 4, 2010. All Open Access, Green Open Access. DOI: 10.1063/1.3475485
    
    Keywords: ...

    Finite element method; Hall effect; Magnetic field effects; Nanostructured materials; Nanostructures; Platinum; Three dimensional; Anomalous Hall effects; Bit-patterned media; Co/Pt multilayer; Cross structures; Magnetic nanostructures; Magnetic switching; Nano-islands; Numerical simulation studies; Output voltages; Patterned magnetic nanostructure; Seed layer; Spatial sensitivity; Switching behaviors; Switching field distribution; Theoretical study; Three dimensional finite element model; Switching.
    
    
    Abstract: ...

    Obtaining an accurate profile of the spatial sensitivity of Hall cross structures is crucial if such devices are to be used to analyze the switching behavior of magnetic nanostructures and determine the switching field distribution of bit patterned media. Here, we have used the anomalous Hall effect to investigate the switching of patterned Co/Pt multilayer magnetic nanoislands, where the Hall cross has been integrated into the Pt seed layer. Using the anomalous Hall output voltage we have observed the magnetic switching of individual islands, allowing the spatial sensitivity across a Hall cross structure to be determined. The experimental results agree well with numerical simulation studies, using a three-dimensional finite element model, and with existing theoretical studies, where the spatial sensitivity of two-dimensional Hall cross structures have been found numerically. © 2010 American Institute of Physics.
    
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16. Qualification of SiP Products: Quasi-Static Cyclic Mechanical Bending
    D. Farley; Y. Zhou; A. Dasgupta; J. F. J. Caers; J. W. C. De Vries;
    In Proceedings of the 2007 ASME International Mechanical Engineering Congress and Exposition Seattle,
    Washington, USA, 2007.

17. Coplanar waveguides and butt-joints on InP
    J.H. den Besten; D. Caprioli; L. Pakula; E. Smalbrugge; T. de Vries; J.J.M. Kwaspen; A.W. Roodnat; R. van Dijk; {van Vliet}, FE; XJM Leijtens; MK Smit;
    In {H Thienpont} (Ed.), Proceedings,
    VUBPress, pp. 197-200, 2001.

18. Simulation aspects of a thermal accelerometer
    U.A. Dauerstadt; P.H.S. de Vries; R. Hiratsuka; J.G. Korvink; P.M. Sarro; H. Baltes; S. Middelhoek;
    Sensors and Actuators A,
    Volume 55 (1996), pp. 3-6, 1996.

19. Silicon accelerometer based on thermopiles
    U.A. Dauderstadt; P.H.S. de Vries; R. Hiratsuka; P.M. Sarro;
    Sensors and Actuators A: Physical,
    Volume 46, Issue 1-3, pp. 201-204, Jan.-Feb. 1995.

20. Design considerations for the thermal accelerometer
    R. Hiratsuka; D.C. van Duyn; T. Otaredian; P. de Vries; P.M. Sarro;
    Sensors and Actuators A: Physical,
    Volume 32, Issue 1-3, pp. 380-385, Apr. 1992.

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