Noise, Large-Signal Modeling and Characterization of InP/InGaAs HBTs

We developed a robust large-signal model for InP/InGaAs HBTs. DC, small-signal, noise and power characteristics of InP/InGaAs HBTs are measured over a wide range of frequencies and bias conditions. A minimum noise figure (FMIN) of 3.5dB, and a gain of 16.8dB are achieved at 10-GHz. These measurement results are the basis for robust nonlinear models of InP/InGaAs HBT devices

Enhanced room temperature mobilities and reduced parallel conduction in hydrogen passivated Si/SiGe heterostructures

The effect of hydrogen passivation on the room temperature mobility and density is studied on n-type $Si_{0.62}Ge_{0.38}$/strained Si modulation-doped structures. Room temperature carrier densities reduced by an order of magnitude while a threefold maximum increase in mobility was observed. By using a two-carrier analysis, it was found that, apart from parallel conduction passivation, the hydrogenation process also improves the channel mobility directly. Plasma and electrolytic hydrogenation were carried out on samples with different spacer thicknesses and mobilities. The plasma method of hydrogenation was found to be more effective when compared to the electrolytic technique. A successful removal of incorporated hydrogen and partial recovery of the control sample was shown by annealing the hydrogenated sample in vacuum at $\sim400^0C$

The constitution of morellin

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Attachment of a hydrophobically modified biopolymer at the oil-water interface in the treatment of oil spills

The stability of crude oil droplets formed by adding chemical dispersants can be considerably enhanced by the use of the biopolymer, hydrophobically modified chitosan. Turbidimetric analyses show that emulsions of crude oil in saline water prepared using a combination of the biopolymer and the well-studied chemical dispersant (Corexit 9500A) remain stable for extended periods in comparison to emulsions stabilized by the dispersant alone. We hypothesize that the hydrophobic residues from the polymer preferentially anchor in the oil droplets, thereby forming a layer of the polymer around the droplets. The enhanced stability of the droplets is due to the polymer layer providing an increase in electrostatic and steric repulsions and thereby a large barrier to droplet coalescence. Our results show that the addition of hydrophobically modified chitosan following the application of chemical dispersant to an oil spill can potentially reduce the use of chemical dispersants. Increasing the molecular weight of the biopolymer changes the rheological properties of the oil-in-water emulsion to that of a weak gel. The ability of the biopolymer to tether the oil droplets in a gel-like matrix has potential applications in the immobilization of surface oil spills for enhanced removal. © 2013 American Chemical Society

Attachment of a Hydrophobically Modified Biopolymer at the Oil–Water Interface in the Treatment of Oil Spills

The stability of crude oil droplets formed by adding chemical dispersants can be considerably enhanced by the use of the biopolymer, hydrophobically modified chitosan. Turbidimetric analyses show that emulsions of crude oil in saline water prepared using a combination of the biopolymer and the well-studied chemical dispersant (Corexit 9500A) remain stable for extended periods in comparison to emulsions stabilized by the dispersant alone. We hypothesize that the hydrophobic residues from the polymer preferentially anchor in the oil droplets, thereby forming a layer of the polymer around the droplets. The enhanced stability of the droplets is due to the polymer layer providing an increase in electrostatic and steric repulsions and thereby a large barrier to droplet coalescence. Our results show that the addition of hydrophobically modified chitosan following the application of chemical dispersant to an oil spill can potentially reduce the use of chemical dispersants. Increasing the molecular weight of the biopolymer changes the rheological properties of the oil-in-water emulsion to that of a weak gel. The ability of the biopolymer to tether the oil droplets in a gel-like matrix has potential applications in the immobilization of surface oil spills for enhanced removal