Willem C. Heerens

Willem C. Heerens
Delft University of Technology | TU · Multi-scale Physics Department

PhD MSc

About

38
Publications
17,792
Reads
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535
Citations
Education
November 1967 - October 1979
Delft University of Technology
Field of study
  • Vacuum technology, Absulute pressure measurement equipment
September 1961 - October 1967
Delft University of Technology
Field of study
  • Applied Physics

Publications

Publications (38)
Conference Paper
Full-text available
The most important results in relation to problems of listening to music for CI-users are given by explaining the experienced differences in a beat experiment and in the way missing fundamentals in a sound pressure stimulus can be heard by normal hearing [NH] persons, while for CI-users this is impossible with the current programs in the CI process...
Poster
Full-text available
Poster as contribution to the Music & CI Symposium concerning Beat and [ Missing] Ffundamental that can be heard by a CI-user. The stimulus to the CI-processor program must be transferred into the sound energy stimulus instead of the sound pressure stimulus.
Article
Full-text available
Clinical study of tympanostomy tube placement for patients with intractable Ménière's disease - Volume 129 Issue 7 - JA De Ru, W C Heerens
Article
Full-text available
Based on our insights derived from literature we arrive at two more basic principles that form the cornerstones of our model: namely, the fact that the attenuation of the eardrum and the ossicular chain are at the root of the extremely large dynamic range of our auditory sense, and the fact that the bone conduction phenomenon is actually the result...
Article
Full-text available
Based on our insights derived from literature we arrive at two more basic principles that form the cornerstones of our model: namely, the fact that the attenuation of the eardrum and the ossicular chain are at the root of the extremely large dynamic range of our auditory sense, and the fact that the bone conduction phenomenon is actually the result...
Article
Full-text available
A survey is given of the theoretical background for designing multi-terminal capacitor sensors of several types, suitable for control of every physical quantity that can be related with the change in position of two carriers, covered with electrodes. Previously published investigations of capacitor sensors, are briefly mentioned, and a description...
Article
Full-text available
A description will be given of a new absolute capacitive thickness gauge for thin layers. The applied method, using a 'baseplate reference' measurement of the substate, followed by a 'layer on baseplate' measurement, enables an uncertainty in the layer thickness of 0.8 nm with a 95% confidence level. The method compensates for tilting of the electr...
Article
Full-text available
By reconsidering the basic principles of capacitance, and also clarifying some of the misconceptions about the principles of guarding, which were correctly described by Kelvin more than a century ago, it is shown how guarded multi terminal capacitor geometries can be designed, analytically precalculated and correctly measured using simplified trans...
Article
Full-text available
The non-linear and hysteretic behavior of piezo actuactors used in scanning probe techniques lim¬its the accuracy of the quantitative interpretation of the measurements. In this paper the design of a novel STM is presented that is equipped with a newly developed capacitive translation sensor. The sensor has been con¬figured to measure translations...
Article
Abstract of WO 9704475 (A1) An XY-displacement device (1) with a four-fold symmetry comprises a reference frame (10); an object mount (20) for holding an object (22) to be displaced; an X-manipulator (100) coupled between the reference frame (10) and the object mount (20), which provides a rigid coupling between the object mount (20) and a piezoele...
Article
Full-text available
Local shear is understood to be one of the principal risk factors for the development of pressure sores. There is a need for a small deformable sensor that can measure the shear force between skin and deformable materials without disturbing the shear phenomenon. In the present study a new shear sensor is introduced with a contact area of 4.05 cm2....
Article
Full-text available
In order to obtain atomic resolution in a transmission electron microscope, a piezo-driven nanostage with subnanometer stability is under development. Inertial sliding motion is used to move the nanostage table in the plane perpendicular to gravity. One of the most important parameters on the way to such a nanostage is the design of the nanostage t...
Article
Full-text available
Piezoelectric actuators that are used in scanning probe microscopes and in precision X–Y translation stages have undesirable properties. Piezoelectric effects like hysteresis, nonlinearity, and drift introduce geometric deformations in the scanning probe microscope images. Due to these deformations, the quantitative interpretation of the absolute s...
Article
Full-text available
A translation stage has been developed for generating displacements with nanometer accuracy and a dynamic range of 10 μm. The stage uses piezo stacks as actuators and is equipped with capacitive sensors which are able to measure displacements with subnanometer resolution. Because the measurements are very accurate, the displacement properties of th...
Article
A capacitive void fraction sensor for use in a rod-bundle geometry was designed using a new design criterion. This criterion states that the response of the sensor to small test bubbles of equal size should be independent of their positions. This so-called homogeneous sensor response replaces the principle of a homogeneous electric field which is u...
Article
The uncertainty in the exact lateral position of the moving part relative to the frame is one of the technical problems in piezo-driven translation stages for submicron translations. This is mainly caused by non-linearities in the piezo actuators and thermal drift in the construction. The piezo voltages are therefore not appropriate as the referenc...
Article
Full-text available
The application of high Tc superconductors, especially thin films, for magnetic lenses is discussed. If a thin film is patterned with a spiral, a small coil is obtained which can be utilized as a magnetic lens. However, because of field strength and rotational symmetry requirements, a number of the patterned thin films need to be stacked. The conce...
Article
Full-text available
The gauge factor of common strain gauges cannot be completely precalculated and needs calibration. Using the uniplanar three-terminal capacitance concept, a capacitive sensor that meets all of the demands necessary for making precision strain gauges can be designed and optimized.The fundamental calculation of such a strain gauge will be given. It c...
Article
Full-text available
This paper presents a simple capacitive displacement sensor based on the application of spatial sampling and Doppler measurement techniques. The theoretical performance of the sensor has been predicted and simulated on a PC, and confirmed experimentally. The prototype sensor shows a resolution and repeatability of 1 μm. A linear measurement range u...
Article
Full-text available
In this article a complete calculation strategy is given for potential and field strength in rotationally symmetric lens systems. The equations for these quantities are based on Fourier–Bessel series solutions. The series coefficients can be given analytically when simple boundary conditions are assumed, such as a rectangular cross section of the s...
Patent
Full-text available
Gauge comprising at least one capacitor for connec- tion into a bridge-circuit, said capacitor having at least one of its electrode support plates coated with an electrode overlay (22) such that a system of sub-electrodes (23, 28, 29) is formed, said subelectrodes (23, 28, 29) mutually separated at least by gaps (21, 25) but even if in geometri- ca...
Article
Full-text available
Investigations of gap influences in circular and linear capacitor geometries, especially cross capacitor geometries, have been performed. For deep gaps between thick electrodes in principle the effective boundaries of electrodes can be positioned in the center of the adjacent gaps. For thin electrodes on dielectric carriers surrounded by gaps, with...
Patent
Full-text available
Multiple terminal capacitor consisting of two opposite electrode plates, at least one thereof being sub-divided into a plurality of sub-electrodes separated from each other by small gaps, said sub-electrodes each forming with an area of the opposite electrode plate an individual sub-capacitor of the plate-capacitor or cross-capacitor type, said sub...
Article
Full-text available
The theoretical background for designing multi-terminal capacitor sensors of several types is described. A brief description of the capacitance bridges used and some interesting results of investigations of laboratory test models are also given. It is concluded that these types of capacitor sensors are highly reliable, that they are pre-calculable,...
Article
Full-text available
A survey will be given of the theoretical background for designing multi terminal capacitor sensors of several types. This in combination with a brief description of the used capacitance bridges and quite remarkable condensed results of investigations of some laboratory test models. Main conclusion is that these types of capacitors sensors are high...
Article
Full-text available
An analytical potential calculation strategy is worked out, using the analytical solution of Laplace’s equation in cylindrical and toroidal configurations with rectangular sectional shape and rotation symmetrical boundary conditions. This strategy makes it possible to calculate the potential distribution to any desired rate of accuracy, even in ver...
Article
Full-text available
The theoretical background for designing multiterminal capacitor sensors of several types is described. A brief description of the capacitance bridges used and some interesting results of investigations of laboratory test models are also given. It is concluded that these types of capacitor sensors are highly reliable, that they are precalculable, h...
Conference Paper
Full-text available
On the basis of some examples different types of multi terminal capacitor sensors are shown, the working principle is explained and a six degrees of freedom capacitive control system is discussed as an example of several feasible applications in microcircuit engineering.
Article
Full-text available
In order to study the liquid distribution in a packed column a multi-channel liquid level measuring system was developed. This system is based on a capacitive measuring method. The system can sample 177 liquid flows simultaneously). The accuracy of the measurements is better than 1% full scale. The whole system has been built with standard commerci...
Article
Full-text available
The optimum geometry of capacitors of rectangular configuration is studied. In configurations of ring capacitors with four electrodes analytical equations for the capacitance including first order gap influences are derived. In cross-section all electrodes have straight sides. From calculations carried out with these equations simple and practical...
Article
A description is given to an absolute calibrated capacitative differential pressure gauge that may overcome many of the difficulties associated with previous capacitative membrane pressure gauges; these difficulties include problems associated with calculation of the gauge factor and thermal instabilities associated with detection system design. Th...
Article
Full-text available
Basic formulas have been obtained for the contribution to the potential in any point of a cylindrical or toroidal volume with rectangular sectional shapes and rotation‐symmetrical boundary conditions. This is done by solving Laplace’s equation in cylindrical coordinates using the method of separation of variables for the cases in which simple but c...
Article
Full-text available
An exact solution has been obtained for the capacitance of Kelvin guard‐ring capacitors with strongly limited radial dimensions compared with the distances between the electrodes. This is done by solving the three‐dimensional Laplace equation by means of separation of variables. From the achieved equations, formulas expressing the influences of sev...

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Project (1)
Project
Since October 2001 my research interest concerns the verification on correct application of physics in explanations and hypotheses about hearing related processes. Until now I have observed that quite a number of current hypotheses are based on misinterpretations of experimental results in terms of physic laws and rules.