Eight-channel p-i-n/HBT monolithic receiver array at 2.5 Gb/s perchannel for WDM applications

We report a monolithic chip incorporating an eight channel p-i-n/HBT photoreceiver array designed for multichannel WDM applications. The p-i-n photodetectors are edge illuminated and centered at a 250 μm pitch for mating with either ribbon fiber connectors or waveguide demultiplexers. Each channel operates at 2.5 Gb/s with an electrical crosstalk of -20 dB between adjacent channels. The average sensitivity of each receiver in the array was measured to be (-20±1) dBm for a bit error rate of 10^-9 at a wavelength of 1.5 μm     

High-speed monolithic p-i-n/HBT and HPT/HBT photoreceiversimplemented with simple phototransistor structure

Monolithic photoreceivers, using the base-collector junction of an InP/InGaAs phototransistor structure for a p-i-n photodetector, have been fabricated for the first time. Bandwidths as high as 3 GHz and bit rates as high as 5 Gb/s, with sensitivities of -22.5 dBm and -21.5 dBm for light focused on the p-i-n or on the first stage transistor of the preamplifier, respectively, have been achieved. These results represent the highest operating speed demonstrated for any phototransistor-based receiver     

Digital Simulation of an Inverter-Fed Self-Controlled Synchronous Motor

This paper describes a digital simulation method for the self-controlled synchronous motor (SCSM) in time domain. A generalized machine model in direct three-phase quantities is used to represent the machine and the fourth-order numerical integration technique of Runge, Kutta, and Gill in [17] is used to solve the machine equations. Performance of the synchronous machine with nonsinusoidal voltages and currents is simulated under both steady-state and transient conditions. The effects of the damper windings and saliency on the torque, and voltage and current waveforms are studied using this digital simulation technique when the machine is operated from a voltage source inverter (VSI) and a current source inverter (CSI).     

Ultrasound-assisted extraction and adsorption of polyphenols from Ginger Rhizome (Zingiber officinale)

Ultrasound-assisted extraction followed by adsorption and desorption was performed successively for efficient recovery of polyphenols from ginger rhizome (Zingiber officinale). The maximum degree of extraction was observed in case of methanol (0.55 mg/ml) followed by acetone (0.52 mg/ml) and ethanol (0.37 mg/ml). At optimized conditions, the polyphenol recovery was found to be 19.2 mg. Amberlite XAD4 had shown the highest adsorption capacity (0.89 mg/ml). Kinetic studies indicated the adsorption equilibrium to be about 20 min. Adsorption capacity was achieved at 25 ± 2°C, and adsorption process exhibited exothermic nature. Freundlich isotherm fitted the data well. Ethanol had shown best desorption efficiency (93.44%).     

Variable‐emittance infrared electrochromic skins combining unique conducting polymers,ionic liquid electrolytes,microporous polymer membranes,and semiconductor/polymer coatings,for spacecraft thermal control

Variable emittance (ε) is a property vital for the increasing needs in thermal control of future microspacecraft. This article describes fabrication, function, and performance of thin‐film, flexible, variable‐emittance (V‐E) electrochromic skins that use a conducting polymer/‐Au/‐microporous membrane (CP/Au/µP) base, and a new, unique ionic liquid electrolyte (IonEl). Poly(aniline‐co‐diphenyl amine) with a long‐chain polymeric dopant is used as the CP. A unique, patented device design yields no barrier between the active, electrochromic CP surface and the external environment, except for a thin, infrared‐transparent semiconductor/polymer film that lowers solar absorptance [α(s)] and protects from atomic‐O/far‐UV. Use of the IonEl requires special activation methods. Data presented show tailorable ε variations from 0.19 to 0.90, Δε values of >0.50 (which is the highest reported thus far for any functional V‐E material, to our knowledge), α(s) < 0.35, and nearly indefinite cyclability. Extended space durability testing, including calorimetric thermal vacuum and continuous light/dark cycling over >7 months under space conditions (<10^?5 Pa vacuum, far‐UV), show excellent durability. Other data show resistance to solar wind, atomic‐O, electrostatic discharge, and micrometeoroids. These lightweight, inexpensive, advanced polymeric materials represent the only technology that can work with micro‐ (<20 kg) and nano‐ (<2 kg) spacecraft, thus eventually allowing for much greater flexibility in their design and potentially “democratizing” the entire space industry, for example, allowing small firms to launch their own, dedicated satellites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40850.