A nano-assembled porous thin film, deposited using the layer-by-layer method and infused with a functional compound, is used for the development of a highly sensitive fibreoptic ammonia sensor. Sensor fabrication involves a 2-stage process: firstly the deposition of the basic porous thin film (poly(diallyldimethylammonium chloride)/SiO2) over a long period grating written in optical fibre, followed by infusion of a porphyrin compound (tetrakis-(4-sulfophenyl)porphine, TSPP), into the porous film. The device shows high sensitivity to ammonia (ca. 1 ppm) when immersed into an aqueous solution.
Developed by the Virginia Bioinformatics Consortium (VBC), GeneX Va is an open source, freeware database and bioinformatics analysis software for archiving and analyzing Affymetrix GeneChip data. It provides an integrated framework for management, documentation, and analysis of microarray experiments and data to support a range of users, from individual research laboratories to institutional microarray facilities. GeneX Va also provides web-based access to a PostgreSQL relational database system with a comprehensive security system. Data can be extracted from the database and delivered to interactive or scriptable statistical analysis protocols. The security system allows each investigator to manage their own array data and analysis output files and also provides custom access privileges for other users, groups, and internal/external collaborators. The analysis interface uses "Analysis Trees," an innovative user interface that allows researchers to interactively create a tree-structured flow chart of analysis routines. The latest GeneX Va software is available from and can be freely downloaded at the Sourceforge web site http://va-genex.sourceforge.net. To allow researchers to access the database and analysis capabilities of the GeneX Va system, microarray data from many VBC GeneChip experiments have been deposited into a public section of the GeneX Va system at the University of Virginia. The VBC GeneX Va sites, which include documentation, are at http://genes.med.virginia.edu/ of the University of Virginia and at http://genex.csbc.vcu.edu/ of the Virginia Commonwealth University.
A 330-500GHz (WR2.2) directional coupler is demonstrated. The coupling is achieved by parallel quarterwavelength gold beams suspended in air over a silicon substrate. The circuit was designed in an "H" shape in order to transition to low loss rectangular waveguide. We present the design and analysis of a WR2.2 coupler with 4dB insertion loss, 10dB coupling factor and 20dB minimum isolation. The techniques we describe can be employed to design high performance, low cost THz components.
This paper reports an approach to designing compact high efficiency millimeter-wave fundamental oscillators operating above the fmax/2 of the active device. The approach takes full consideration of the nonlinearity of the active device and the finite quality factor of the passive devices to provide an accurate and optimal oscillator design in terms of the output power and efficiency. The 213-GHz single-ended and differential fundamental oscillators in 65-nm CMOS technology are presented to demonstrate the effectiveness of the proposed method. Using a compact capacitive transformer design, the single-ended oscillator achieves 0.79-mW output power per transistor (16 µm) at 1.0-V supply and a peak dc-to-RF efficiency of 8.02% (VDD=0.80 V) within a core area of 0.0101 mm 2 , and the measured phase noise is −93.4 dBc/Hz at 1-MHz offset. The differential oscillator exhibits approximately the same performance. A 213-GHz fundamental voltage-controlled oscillator (VCO) with bulk tuning method is also developed in this work. The measured peak efficiency of the VCO is 6.02% with a tuning rang of 2.3% at 0.6-V supply.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.