Micro mixer with fast diffusion

A concept for micromixing of liquid is introduced, and its feasibility is demonstrated. The mixer allows fast mixing of small amounts of two liquids and is applicable to microliquid handling systems. The mixer has a channel for the liquid, an inlet port for the reagent, a 2.2-mm×2-mm×330-μm mixing area, and 400 micronozzles (15 μm×15 μm) through with a reagent is injected into the sample liquid. The resulting microplumes greatly increase the contact surface between the two liquids and hasten the speed of the mixing by diffusion. The fabrication process is extremely simple. The mixing is complete within a few seconds; a homogeneous state of mixing is reached in 1.2 s when the total volume injected is 0.5 μl and the injection flow rate is 0.75 μl/

Performance of thermally excited resonators

A study of electrothermal excitation of micromachined silicon beams is reported. The temperature distribution is calculated as a function of the position of the transducer, resulting in stress in the structure which reduces the resonance frequency. Test samples are realized and measurements of resonance frequency, vibration shape and vibration amplitude are carried out. There is a satisfactory agreement between theory and experiment at small thermal stresses. Near the buckling load we find distinct deviations from theory which are ascribed to mechanical imperfections of the beams

High resolution shadow mask patterning in deep holes and its application to an electrical wafer feed-through

The paper presents a technique to pattern materials in deep holes and/or on non-planar substrate surfaces. A rather old technique, namely, electron-beam evaporation of metals through a shadow mask, is used. The realization of high-resolution shadow masks using micromachining techniques is described. Further, a low ohmic electrical wafer foed-through with a small parasitic capacitance to the substrate and a high placing density is presented

Artificial lateral-line system for imaging dipole sources using Beamforming techniques

AbstractIn nature, fish have the ability to localize prey, school, navigate, etc. using the lateral-line organ [1]. Here we present the use of biomimetic artificial hair-based flow-sensors arranged as lateral-line system in combination with beamforming techniques for dipole source localization in air. Modelling and measurement results show the artificial lateral-line ability to image the position of dipole sources accurately. Such systems open possibilities for flow-based near-field environment mapping which can be beneficial e.g. to robot guidance applications

Highly sensitive micro coriolis mass flow sensor

We have realized a micromachined micro Coriolis mass flow sensor consisting of a silicon nitride resonant tube of 40 ?m diameter and 1.2 μm wall thickness. Actuation of the sensor in resonance mode is achieved by Lorentz forces. First measurements with both gas and liquid flow have demonstrated a resolution in the order of 10 milligram per hour. The sensor can simultaneously be used as a density sensor

Optimization of the Lorentz Force Actuation for a micro Coriolis mass flow sensor

In this paper we present Finite Element models to optimize the Lorentz force actuation of a micro Coriolis mass flow sensor. The models specify several different configurations for the permanent magnets used to create the magnetic field for the actuation. The models are used to compare the different configurations with relation to the strength of the Lorentz force used for actuation. Using these models the magnetic field outside the sensor area has been reduced by 6 orders of magnitude. The models have been validated with measurements

Single chip flow sensing system with a dynamic flow range of more than 4 decades

We have realized a micromachined single chip flow sensing system with an ultra-wide dynamic flow range of more than 4 decades, from less than 0.1 up to more than 1000 μl/h. The system comprises both a thermal and a micro Coriolis flow sensor with partially overlapping flow ranges