Rise time

About: Rise time is a research topic. Over the lifetime, 4748 publications have been published within this topic receiving 47512 citations.

Low-power and high-speed thermo-optic switch using hybrid silica/polymer waveguide structure: design, fabrication and measurement

Abstract: Response speed and power consumption are improved for a Mach–Zehnder interferometer (MZI) thermo-optic (TO) switch, by using a hybrid silica/polymer waveguide structure and optimizing both the thickness of the silica under cladding and that of the PMMA-GMA upper cladding. Fabrication techniques, including chemical vapor deposition (CVD), spin-coating and wet-etching, are adopted to develop the switch sample. Under 1550 nm wavelength, the driving powers under ON and OFF states are measured to be 0 and 13 mW, respectively, indicating a switching power of 13 mW. The fiber-to-fiber insertion loss under the ON state is 15 dB, the extinction ratio between the ON state and the OFF state is 18.3 dB, and the rise time and fall time are 73.5 and 96.5 µs, respectively. Compared with the TO switches based on Si/SiO2 or all-polymer waveguide structure, the proposed device possesses both low power consumption and fast response speed, by virtue of the large TO coefficient of the polymer core, thin upper/under claddings ...

Mass calibration of a matrix-assisted laser desorption/ionization time-of-flight mass spectrometer including the rise time of the delayed extraction pulse.

Abstract: To utilize fully modern MALDI-TOF and TOF/TOF mass spectrometers with mass resolution exceeding 10,000 and 2 ppm precision of flight time measurements for high mass accuracy, the model of ion motion used in the mass calibration equation must be expanded. The standard three-term equation providing up to 5-10 ppm (rms) mass accuracy with internal standards was modified with an additional term accounting for the finite rise time of the high-voltage extraction pulse. This new four-term calibration equation minimizes the effect of systematic error resulting from the fact that ion velocities are mass dependent due to the rise time of the extraction pulse. Applying this new calibration equation to a mass spectrum obtained in an axial MALDI-TOF MS containing 70 peaks (sodiated PEG), each with a signal-to-noise ratio greater than 100, a mass accuracy of 1.6 ppm (rms) was obtained over the mass range 1.0-4.0 kDa compared with 3.6 ppm (rms) with the standard three-term equation. The physical basis of the effects of the finite extraction pulse rise time on mass calibration is examined for axial MALDI-TOF mass spectrometers, as well as for orthogonal acceleration TOF mass spectrometers.

4kV/30kHz short pulse generator based on time-domain power combining

Abstract: Using avalanche transistor as the switch of Marx circuit, a new type of all-solid-state pulse generator is researched, which can generate short unipolar pulse. The peak-voltage is 2kV as the load resistor is 50Ω, the pulse width is 1.6ns, the rise time is 250ps, the jitter is less than 30ps, and the repetition can reach to 30kHz. Then, combining short pulse through mcirostrip power combiner is analyzed. Four high-stability pulse generators are combined, which generates higher peak-voltage to 3.9kV. The combining efficiency reaches to 97.5%.

Design of Experiments for Stator Windings Insulation Degradation under High dv/dt and High Switching Frequency

Abstract: SiC power devices are gaining increased interest due to their superior performance and increased efficiency in motor drives compared to traditional Si-based IGBT converters. However, the increased switching frequency and much faster switching transients (high dv/dt) of Silicon Carbide (SiC) compared to their IGBT counterparts, can result in increased stress in electrical machines. To quantify these detrimental effects on machine insulation lifetime, a series of tests are conducted on electrical stators representative of typical low voltage machines used in traction and industrial applications. A Design of Experiment (DoE) methodology is employed to identify the test sequence using three stressors. In particular, three values of DC link voltage level, rise time or slew rate of the voltage waveform, and switching frequency, respectively are considered. The paper describes the planned tests and conditions, the insulation health monitoring method employed, and preliminary results.

Particle-in-cell simulation of an electron shock wave in a rapid rise time plasma immersion ion implantation process

Abstract: A one-dimensional Monte Carlo collision‐particle-in-cell plasma computer code was used to simulate plasma immersion ion implantation by applying a negative voltage pulse to the substrate while the reactor wall is grounded. The results presented here show the effect of short rise time pulses: for rise times shorter than the electron plasma period stypically 5 ns/ kVd, an electron shock wave is observed where a rapidly expanding sheath heats the electrons up to high energies. Many of these fast electrons are expelled from the plasma leading to a high plasma potential and thus to a high surface electric field on the earthed electrode which could give rise to non-negligible electron field emission. © 2005 American Institute of Physics . fDOI: 10.1063/1.1872894g