High performance GaAs MESFETs with molecular implanted and optimized lowly-doped drain structure for maximized speed, gain and breakdown performance

GaAs MESFETs with novel lowly-doped drain structures have been developed utilizing molecular implants of silicon trifluoride. Short-channel effects in the 1/4 μm enhancement- and depletion-mode transistors have been suppressed with drain-induced barrier height lowering of less than 70 mV/V and pinch-off voltage shifts of less than 220 mV as the gate length was scaled from 1.0 to 1/4 μm. The 3-terminal breakdown, the transconductance to output conductance ratio, and the unity current gain, cut-off frequency were simultaneously optimized. The E-mode device possessed breakdown of >10 V, G_m · R_ds > 9.5, F_t > 55 GHz, and nominal on-resistance of 2.1 Ω mm while the D-mode device had breakdown >10 V, G_m · R_ds > 6.0, F_t > 45 GHz, and nominal on-resistance of 1.9 Ω mm. These optimized transistors enabled the realization of a variety of low-power digital and high-power mixed signal circuits, using 3-level source-coupled transistor and common-mode logic, such as laser and electro-optic drivers, highly integrated transceivers, multiplexers, demultiplexers, and clock data recover circuits.     

A Novel Three-Dimensional Hydrogel-Based Microarray Platform

Three dimensional (3D) microarrays utilizing hydrogel matrixes are becoming increasingly attractive as a desired format for bio-analysis. These materials offer significant advantages as a scaffolding for capture agents over more conventional two dimensional (2D) printed formats in both captures per site and the ability to provide an environment more closely resembling that of a free solution. Biocept has developed a flexible three dimensional polyethylene glycol (PEG) polymer based platform suitable for a variety of biological assays. This novel approach is simple, biocompatible and provides a high degree of reproducibility and very low variability in the final array.     

Compassion Practicum: A Capstone Design Experience at the United States Military Academy

A partnership has been developed linking the United States Military Academy and Special People in the Northeast, a non-profit agency for the mentally and physically handicapped children and adults based in Philadelphia. The present work documents a student design team's design and construction of a ticket-tearing device for a young man in the advanced stages of cerebral palsy and concludes with an evaluation of the entire process.     

Mechanism and kinetics of the free radical ring-opening polymerization of cyclic allylic sulfide lactones

The polymerization of 7-, 8- and 11-membered lactones, 6-methylene-1,4-oxathiepan-7-one, 3-methylene-1,5-oxathiocan-2-one and 3-methylene-1-oxa-5-thiacycloundecan-2-one in benzene at 70, 40–70 and 40–65 °C, respectively, is presented. All polymerizations proceeded with complete ring-opening up to approximately 25% conversion, where insoluble polymer was formed. Evidence is given attributing polymer double bond loss to crosslinking, although redistribution of the molecular weights via addition to polymer double bonds followed by β-fragmentation also appears to occur for polymerizations of the 8- and 11-membered lactones. Michael adducts of lactones with 2-methyl-2-propanethiol were prepared as models for chain-transfer products of hydrogen abstraction by carbon-centred radicals. Polymerization rates were found to increase marginally with ring size. Arrhenius parameters obtained for the polymerizations of the 8- and 11-membered lactones indicated that the addition step was more important than fragmentation in determining the rate of propagation.     

Modeling and forecasting the U.S. manufacturing aggregate energy intensity

Two forecasting models are developed for forecasting the U.S. manufacturing aggregate fuel and electricity intensities. The models are both simple to apply and capable of identifying the effect of underlying forces of aggregate energy intensity change. The validation of the results provided by these models is performed by comparing these results with those rendered by conventional decomposition techniques based on economic index numbers. The results indicate that the aggregate fuel intensity is expected to decline by 3.2%yr^?1 from the year 2000 to 2010, of which 1.1%yr^?1 is due to structural effect, i.e. a share of 32.9% of aggregate fuel intensity change. The results also show that in the same period the aggregate electricity intensity is expected to decline at a rate of 1.2%yr^?1, of which 0.6%yr^?1 is due to structural effect, i.e. a share of 46.3% of aggregate electricity intensity change. Copyright © 2007 John Wiley & Sons, Ltd.     

Piloting of anionic polymerization of styrene in tetrahydrofurant

Anionic polymerization of styrene in THF with n‐butyllithium/alpha‐methylstyrene initiator is described as a first step in preparation of a styrenic block copoly‐mer. In order to suppress rapid decay of living alpha‐methylstyrene unimers, which occurred at room temperature, the initiation reaction was carried out at ?20(+5)°C. The kinetic parameters of this decay reaction were determined and used for process optimization. By combining experiments with modelling of styrene propagation reaction all key process parameters were defined for l‐L, 38‐L, and 189‐L reactors. A good match was demonstrated between the model and experimental propagation exotherm for semibatch reaction conditions. Overall, it was demonstrated that technical grade THF and styrene could be used at pilot plant scale to prepare well‐defined polymers up to Mn 22 000 via the “living” polymerization mechanism. The resulting polymers had narrow molecular weight distributions (1.06 < Mw/Mn < 1.30).     

Disorders of adult attachment.

This article presents an overview of J. Bowlby's framework of attachment (e.g., 1990) for conceptualizing adult psychopathology and its application to clinical practice. The theory proposes that psychological disorders reflect an internalization of adverse attachment experiences, both current and past, and in particular those that undermine self-reliance and feelings of security. Clinical syndromes indicate intensification of anxiety, depression, and/or anger to a degree which interferes with adaptive functioning and interactions with others. The secure base of therapy provides a new model of what close relationships can be like, as well as a setting for exploring and possibly modifying the meaning given to separation and loss experiences. Issues of prevention and social policy are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)