We present a novel continuous electrodeless separation structure based on dielectrophoresis (DEP). The non-uniform electric field is generated by applying voltage over a circular channel. Driven by the electro-osmotic flow, the particles with different dielectric properties move continuously to the different location across the channel as they flow due to the different DEP force, thus continuously separated into the different outlets. The finite element modelling and simulation results show it can separate particles of different dielectric properties in both spatial and time domain. Compared with the previously reported dieletrophoretic separation using electrode arrays [1-10], this structure is more easily fabricated, mechanically robust and chemically inert. And compared with the previously reported electrodeless dielectrophoretic separation methods [11-14], this structure achieves higher throughput and continuous separation.
In minimal invasive surgery usually an endoscope is used to show the surgeon what is happening inside the human body. However, this view is very limited and gives no information of instrument positions outside the camera view. A new positioning system is proposed that should give the surgeon the exact location and orientation of the instruments in the patient. The measuring 'system consists of markers placed on the instruments, outside of the human body. Knowing the dimensions of the usually rigid instruments it is possible to calculate their position and orientation inside the human body from the marker positions. Two pairs of ultrasound markers placed on each instrument will suffice to measure both the position and orientation. The detection of marker positions is realized by an array of ultrasound receivers. The influence of variations in temperature, humidity and pressure of air on the phase-shift and time-of-flight methods was investigated. Using the time of flight method, the variations of distance and time of flight have a linear correlation and it seems that an accurate measurement system can be achieved.
A --A new positioning sysfem is proposed fhat should give fhe surgeon fhe exact location und orienfafion of the insfrumenis in fhepatienf. The measuring system employ ulfrasound marked frunsmiffersplaced on the insfruments, outside of the human body. Knowing the dimensions of fhe usuully rigid insfrumenfs if is possible lo calculate their position and orientafion inside fhe pufienf from the markers positions. The defection is realized by an array of ulnasound receivers. The lime offighf (T0F)principle is used lo calculute the disrcrnce transmiller-receivers. The measuremenis proved fhat the cross correlation digitul technique permifs a better resolution and accuracy of TOF results. Using this technique we obtained a resolufion of 0.7 mm in determining the markerposifions. The maximum absolufe error of measurements was abouf 2.8 m m
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