Bulk Carbon Nanotubes for Micro Anemometry (Invited Paper)

2003 ◽  
Author(s):  
Victor T. S. Wong ◽  
Wen J. Li
Keyword(s):  
Current Mode ◽  
Constant Current ◽  
Experimental Measurements ◽  
Dynamic Characterization ◽  
Temperature Coefficient Of Resistance ◽  
Micro Electro Mechanical Systems ◽  
Mode Configuration ◽  
Multi Walled Carbon Nanotube ◽  
Constant Current Mode ◽  
Bulk Carbon

We have successfully developed a process to manipulate post-growth multi-walled carbon nanotube (MWNT) by AC electrophoresis to form resistive elements and showed that these elements can potentially served as novel sensing elements for micro/nano thermal and anemometry sensing. We have measured the temperature coefficient of resistance (TCR) of these MWNT bundles and integrated them into constant current mode configuration for dynamic characterization. Preliminary experimental measurements showed that the devices could be operated in micro-watt power range for micro thermal and anemometry sensing. This operation range is three orders of magnitude lower than conventional Micro-Electro-Mechanical Systems (MEMS) polysilicon sensors in constant current (CC) mode configuration. In addition, the devices exhibited very fast frequency response (> 100 kHz) in CC mode. Based on these results, we are currently developing polymer-based MWNT embedded sensor for various micro/nano fluidic applications.

scholarly journals Fabrication of freestanding Pt nanowires for use as thermal anemometry probes in turbulence measurements

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Hai Le-The ◽  
Christian Küchler ◽  
Albert van den Berg ◽  
Eberhard Bodenschatz ◽  
Detlef Lohse ◽  
...  
Keyword(s):  
Room Temperature ◽  
Fluid Velocity ◽  
Current Mode ◽  
Constant Current ◽  
Small Scale ◽  
Turbulence Measurements ◽  
High Dynamic ◽  
Scale Turbulence ◽  
Constant Current Mode ◽  
Pt Nanowires

AbstractWe report a robust fabrication method for patterning freestanding Pt nanowires for use as thermal anemometry probes for small-scale turbulence measurements. Using e-beam lithography, high aspect ratio Pt nanowires (~300 nm width, ~70 µm length, ~100 nm thickness) were patterned on the surface of oxidized silicon (Si) wafers. Combining wet etching processes with dry etching processes, these Pt nanowires were successfully released, rendering them freestanding between two silicon dioxide (SiO2) beams supported on Si cantilevers. Moreover, the unique design of the bridge holding the device allowed gentle release of the device without damaging the Pt nanowires. The total fabrication time was minimized by restricting the use of e-beam lithography to the patterning of the Pt nanowires, while standard photolithography was employed for other parts of the devices. We demonstrate that the fabricated sensors are suitable for turbulence measurements when operated in constant-current mode. A robust calibration between the output voltage and the fluid velocity was established over the velocity range from 0.5 to 5 m s−1 in a SF6 atmosphere at a pressure of 2 bar and a temperature of 21 °C. The sensing signal from the nanowires showed negligible drift over a period of several hours. Moreover, we confirmed that the nanowires can withstand high dynamic pressures by testing them in air at room temperature for velocities up to 55 m s−1.

Constant-Current-Mode LAPS (CLAPS) for the Detectionof Penicillin

2001 ◽  
Vol 13 (8-9) ◽  
pp. 733-736 ◽  
Author(s):  
Tatsuo Yoshinobu ◽  
Holger Ecken ◽  
Arshak Poghossian ◽  
Anette Simonis ◽  
Hiroshi Iwasaki ◽  
...  
Keyword(s):  
Current Mode ◽  
Constant Current ◽  
Constant Current Mode

A computer-controlled stimulator with applications to cardiac electrophysiology

1980 ◽  
Vol 239 (2) ◽  
pp. H278-H282
Author(s):  
V. Elharrar
Keyword(s):  
Cardiac Electrophysiology ◽  
Current Mode ◽  
Pulse Amplitude ◽  
Constant Current ◽  
Constant Voltage ◽  
S 100 ◽  
Computer Controlled ◽  
Constant Current Mode

A computer-controlled stimulator compatible with S-100 microcomputers using an 8080 or Z-80 microprocessor is described. The pusle interval is controlled from 1 to 65,535 ms and the pulse duration from 1 to 255 ms by steps of 1 ms. The pulse amplitude is controlled from 0 to 10.24 V (in constant voltage mode) and from 0 to 1 mA (in constant current mode) by steps of 4 mV and 4 mu A, respectively. The characteristics of the stimuli and their timing can be altered automatically according to programmed protocols that may or may not take into account the response of the biologic preparation. Applications of this stimulator to the study of experimental cardiac electrophysiology are illustrated in vivo and in vitro.

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