A low-voltage current-mode active pixel sensor (APS) capable of operating from a 1 V power supply in a 0.35 /spl mu/m standard CMOS process is proposed. The pixel utilizes a PMOS transistor biased in the linear region...
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A low-voltage current-mode active pixel sensor (APS) capable of operating from a 1 V power supply in a 0.35 /spl mu/m standard CMOS process is proposed. The pixel utilizes a PMOS transistor biased in the linear region of operation to produce an output current linearly proportional to the integrated voltage. The 10/spl times/10 /spl mu/m/sup 2/ fabricated pixel has a 32% fill factor and an adjustable conversion gain of 6.3 pA/e~. This paper presents an analysis and simulations of the image sensor.
Upon uniform stimulation by the chemoattractant cAMP, Dictyostelium cells exhibit a biphasic response. Initially, a rapid rise in the localized accumulation of PI(3,4,5)P/sub 3/ is accompanied by an increase in actin ...
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Upon uniform stimulation by the chemoattractant cAMP, Dictyostelium cells exhibit a biphasic response. Initially, a rapid rise in the localized accumulation of PI(3,4,5)P/sub 3/ is accompanied by an increase in actin polymerization. This response peaks approximately 5-10 seconds after stimulation. It is then followed by a slower, smaller phase peaking approximately two minutes after the stimulus. Until recently, the nature of this biphasic response has been poorly understood. Moreover, the origin for the secondary phase is unknown. In this paper we conjecture the existence of a feedback path between the response and stimulus. Using a mathematical model of the chemoattractant-induced response in cells, and standard tools from control engineering, we show that positive feedback may elicit this second peak. Finally, we discuss some of the literature that suggests the possible existence of this loop.
Sonar array technology enables sensing of both range and angle bearing of objects with respect to the array. Instead of relying on a narrow angle of transmission and reception and multiple sensor positions, one array ...
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Sonar array technology enables sensing of both range and angle bearing of objects with respect to the array. Instead of relying on a narrow angle of transmission and reception and multiple sensor positions, one array can receive returns from a large area and still offer angular localization of targets. We have designed and constructed array processing circuitry that uses mixed-signal spatiotemporal frequency filtering in order to extract wavefront velocity across the array. From wavefront velocity, the angular bearing of a return is determined. This system was demonstrated in a functional test using single and multiple objects. The 2D performance is presented here.
The Tb5 (Six Ge4-x) alloy system has many features in common with the Gd5 (Six Ge4-x) system although it has a more complex magnetic and structural phase diagram. This paper reports on the magnetic anisotropy and magn...
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We show that there are no fundamental limits to the maximum time delay that can be achieved for pulses propagating through slow-light media, thus suggesting the importance of slow-light methods for practical applicati...
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Strong enhancement of optically excited THz emission from GaSb due to compensation of native acceptors by tellurium donors has been observed. THz emission of compensated GaSb is an order of magnitude stronger than und...
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Novel ZnO nanostructures such as hollow nanospheres, nano-cages, nanoneedles, tetra-pods, nanowires, aligned nanorods and nanotubes are synthesized via thermal evaporation of ZnO and graphite powder mixtures in reduce...
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Novel ZnO nanostructures such as hollow nanospheres, nano-cages, nanoneedles, tetra-pods, nanowires, aligned nanorods and nanotubes are synthesized via thermal evaporation of ZnO and graphite powder mixtures in reduced oxygen atmosphere in the presence of argon and nitrogen flows. The ZnO nanostructures, especially nanospheres, have a unique shape and are hollow inside with walls densely decorated with aligned nanowires. Photoluminescence of synthesized ZnO structures measured at 300 K exhibits a strong near band edge peak at ∼380 nm and deep level green band centered at ∼550 nm. Fabricated ZnO structures can be studied for various applications in optoelectronics and sensors.
The junction temperature of AlGaN/GaN ultraviolet (UV) Light-Emitting Diodes (LEDs) emitting at 295 nm is measured by using the temperature coefficients of the diode forward voltage and emission peak energy. The high-...
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Truly single-mode amplification of femtosecond pulses from a fiber oscillator to ~100 nJ is demonstrated. Amplitude and phase noise characterization of the source and its robustness demonstrates its potential for many...
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Amplification of femtosecond pulses directly from a fiber oscillator in a truly single-mode fiber amplifier to ~100 nJ is demonstrated. Its simplicity and robustness renders the laser attractive for certain applicatio...
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