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Full-Text Articles in Physics

Detection And Counting Of Micro Scale Particles And Pollen Using A Multi-Aperture Coulter Counter, Ashish Jagtiani, Jiang Zhe, Jun Hu, Joan Carletta Aug 2015

Detection And Counting Of Micro Scale Particles And Pollen Using A Multi-Aperture Coulter Counter, Ashish Jagtiani, Jiang Zhe, Jun Hu, Joan Carletta

Joan Carletta

We demonstrate a high throughput, all-electronic Coulter-type sensor with four sensing microapertures to detect and count micro-scale particles. Four particle samples are utilized for this study: polymethacrylate particles 40 µm and 20 µm in diameter, Juniper Scopulorum (Rocky Mountain Juniper) pollen and Cottonwood pollen particles. The two types of pollen particles are roughly 20 µm in diameter. The particles are mixed with deionized water and forced to pass through the microapertures. Voltage pulses across all four apertures are recorded and analysed. Results demonstrate that the sensor can detect and count particles through its four sensing apertures simultaneously. Thus, the counting …


Detection And Counting Of Micro Scale Particles And Pollen Using A Multi-Aperture Coulter Counter, Ashish Jagtiani, Jiang Zhe, Jun Hu, Joan Carletta Apr 2015

Detection And Counting Of Micro Scale Particles And Pollen Using A Multi-Aperture Coulter Counter, Ashish Jagtiani, Jiang Zhe, Jun Hu, Joan Carletta

Dr. Jiang Zhe

We demonstrate a high throughput, all-electronic Coulter-type sensor with four sensing microapertures to detect and count micro-scale particles. Four particle samples are utilized for this study: polymethacrylate particles 40 µm and 20 µm in diameter, Juniper Scopulorum (Rocky Mountain Juniper) pollen and Cottonwood pollen particles. The two types of pollen particles are roughly 20 µm in diameter. The particles are mixed with deionized water and forced to pass through the microapertures. Voltage pulses across all four apertures are recorded and analysed. Results demonstrate that the sensor can detect and count particles through its four sensing apertures simultaneously. Thus, the counting …


Superlattice Ultrasonic Generation, Thomas E. Wilson, M. Oehme, E. Kasper, H-J. L. Gossmann Feb 2014

Superlattice Ultrasonic Generation, Thomas E. Wilson, M. Oehme, E. Kasper, H-J. L. Gossmann

Thomas E. Wilson

We report the first experimental evidence for the resonant excitation of coherent high-frequency acoustic phonons in semiconducting doping superstructures by far-infrared laser radiation. After a grating-coupled delta-doped silicon doping superlattice is illuminated with ~1 kW/mm2 nanosecond-pulsed 246 GHz laser radiation, a delayed nanosecond pulse is detected by a superconducting bolometer at a time corresponding to the appropriate time-of-flight for ballistic longitudinal acoustic phonons across the (100) silicon substrate. The absorbed phonon power density in the microbolometer is observed to be ~10 μW/mm2, in agreement with theory. The phonon pulse duration also matches the laser pulse duration. The absence of any …