A Polyacrylamide Gel with Reversible DNA Crosslinks

  • A.P. Mills J.
  • D.C. Lin
  • N.A. Langrana
  • Yurke B.

This study investigates the use of polyacrylamide hydrogel as the basis for a novel approach to biomaterials engineering. In this system, DNA replaces bis as the crosslinking agent. Using DNA introduces a number of additional parameters that can be manipulated to influence the mechanical properties of the material. It also ...

Simultaneously at Two Wavelengths (5.0 and 7.5 mum) Single-Mode and Tunable Quantum Cascade Distributed Feedback Lasers

  • A. Straub
  • A.M. Sergent
  • Capasso F.
  • Cho A.
  • Gmachl C.
  • Sivco D.

Quantum cascade distributed feedback (QC-DFB) lasers based on a hetergeneous-cascade active waveguide core and a multi-sectioned cavity featuring two different Bragg gratings are demonstrated. Optimized lasers display single-mode emission at lambda ~ 5.0 and 7.5 mum simultaneously and a tunability on both modes equal to single-wavelength QC-DFB lasers.

High Mobility AlGaN/GaN Heterostrctures Grown by Plasma-Assusted Molecular Beam Epitaxy on Semi-Insulating GaN Templates Prepared by Hydride Vapor Phase Epitaxy

  • A.M. Sergent
  • D.V. Lang
  • G. Kowach
  • H.L. Stormer
  • Hsu J.
  • J. Caissie
  • K.M. Molvar
  • L.J. Mahoney
  • Manfra M.
  • Pfeiffer L.
  • R.J. Molnar
  • S. Syed
  • S.N.G. Chu
  • W. Pan
  • Weimann N.
  • West K.

We report on an extensive study of the growth and transport properties of the two-dimensional electron gas (2DEG) confined at the interface of AlGaN/GaN heterostructures grown by molecular beam epitaxy (MBE) on thick, semi-insulating GaN templates prepared by hydride vapor phase epitaxy (HVPE).

Single Crystal GaN/Gd2)3/GaN Heterostructure

  • C.M. Lee
  • Cho A.
  • J. Kwo
  • J.I. Chyi
  • J.P. Mannaerts
  • K.A. Anselm
  • Kortan A.
  • M. Hong
  • Ng H.
  • S.N.G. Chu

Heteroepitaxy of single crystal Gd203 on GaN (with a wurtzite hexagonal close-packed (hcp) structure) and single crystal GaN on Gd203 was achieved. In-situ reflection high-energy electron diffraction reveals a six-fold symmetry in the in-plane epitaxy of the rare earth oxide on GaN and also in the overgrowth of GaN on ...

Comparative Study of Ultrafast Intersubband Electron Scattering Times at ~1.55 mum Wavelength in GaN/AlGaN Heterostructures

  • Cho A.
  • Gmachl C.
  • Heber J.
  • Ng H.

We report on a comparative study of room temperature intersubband electron scattering lifetimes in GaN/AlGaN single and coupled double multiple quantum well samples with peak absorption wavelengths ranging from 1.4 to 1.7 mum. Using time-resolved pump-probe spectroscopy, electron scattering times as short as ~160 fs have been measured for a ...

Mid-Infrared (lambda ~~ 7.4 mum) Quantum Cascade Laser Amplifier for High Power Single-Mode Emission and Improved Beam Quality

  • Capasso F.
  • Gmachl C.
  • Sivco D.
  • Troccoli M.

A quantum cascade laser amplifier has been developed. It was used to obtain high power single mode emission at lambda ~~ 7.4 mum from a quantum cascade distributed feedback laser, together with enhanced beam quality. Laser and amplifier are directly coupled in a master oscillator power amplifier configuration. Peak optical ...

Iterating Transducers

  • Dams D.
  • M. Steffen
  • Y. Lakhnech

In this paper we give a partial algorithm to compute a finite-state transducer T* for a general class of transducers.

HAGAR: Efficient Multi-Context Graph Processors

  • Huelsbergen L.
  • Mencer O.
  • Z. Huang

Graph algorithms, such as vertex reachability, transitive closure, and shortest path, are fundamental in many computing applications. We address the question of how to utilize the bit-level parallelism available in hardware and specifically in FPGAs to implement such graph algorithms for speedup.

DTD-Directed Publishing with Attribute Translation Grammars

  • Benedikt M.
  • Chan C.
  • Fan W.
  • Rastogi R.

We present a framework for publishing relational data in XML, with respect to a fixed DTD. In data exchange on the Web, XML views of relational data are typically required to conform to a predefined DTD. The presence of recursion in a DTD as well as non-determinism makes it challenging ...

Design and Implementation of Wavelength Flexible Nodes

  • Chandrasekhar S.
  • Giles R.
  • Leuthold J.
  • Neilson D.
  • Nuzman C.
  • Ryf R.

We present an experimental and analytic study of a photonic (all-optical) crossconnect with wavelength flexibility. The crossconnect is designed to scale efficiently with increasing traffic volumes and bit rates on dense wavelength division multiplexed optical networks. At the heart of the crossconnect is a MEMS-based photonic switch fabric capable of ...

Utterance Verification Based on Neighborhood Information and Bayes Factors

  • Jiang H.
  • Lee C.

In this paper, we propose to use neighborhood information in model space to perform utterance verification (UV). At first, we present a nested-neighborhood structure for each underlying model in model space and assume the underlying model's competing models sit in one of these neighborhoods, which is used to model alternative ...

A Tutorial on Pronounciation Modeling for Large Vocabulary Speech Recognition

  • Fosler-Lussier J.

Automatic speech recognition (ASR) research has progressed from the recognition of read speech to the recognition of spontaneous conversational speech in the past decade, prompting some in the field to re-evaluate ASR pronounciation models and their role of capturing the increased phonetic variability within unscripted speech. Two basic approaches for ...

Reconfigurable Multiband Radio -- Enabling Technologies RF-MEMS and GaN

  • Eckl W.
  • Fischer G.

Outline of presentation: (1) Motivation, (2) SR-Radio architecture, (3) Problematic Components, (4) Difference of SRR to SDR, (5) Conclusion and work direction.

Standards Bring More Flexibility to Optical Transport

  • Helvoort H.

About four years ago consensus emerged among major market researchers indicating, that while voice traffic continues to grow at a moderate rate, data transport will dominate most networks by the years 2002-2005 requiring more bandwidth than was anticipated. The new applications that are emerging requiring transport over optical networks are: ...

Silsesquioxane Resins as High Performance Solution Processable Dielectric Materials for Organic Transistor Applications

  • Bao Z.
  • Kuck V.
  • Paczkowski M.
  • Rogers J.

Silsesquioxane polymers have been successfully used as the dielectric layer in organic field-effect transistors (FET) deposited on robust, plastic substrates. Performance comparable to that found with silicon substrates having SiO2 as the active dielectric layer was observed with six p- and n- channel organic semiconductors. These organopolysiloxane materials can be ...

Subsolidus Phase Equilibria and Crystal Chemistry in the System BaO-TiO2-Ta2-O5

  • Siegrist T.

Complex titanates, tantalates, and niobates display important dielectric properties that are exploitable, for example, in wireless communications applications [1-5]. As part of a continuing program to elucidate phase relations, crystal chemistry, and the occurrence of new compounds in this class of ceramic oxides, the first systematic study of the BaO-TiO2-Ta2O5 ...

Impact Of Rate Control On The UMTS Backhaul Capacity In The Presence Of Traffic From Multiple Services

  • Abraham S.
  • Chuah M.
  • Saraydar C.

This memo studies the capacity and utilization of the downlink of the Iub Interface, which lies between the Radio Network Controller (RNC) and the base station (NodeB) in a UMTS network.

Subband All Pass Filter Architectures With Applications To Dispersion And Dispersion Slope Compensation And Continuously Variable Delay Lines

  • Madsen C.

A new filter architecture is proposed which employs optical half-band and allpass filters but circumvents the typical tradeoff between passband width and peak delay inherent to allpass filters. A filter design for a dispersion compensator with a tuning range of +/-1000 ps/nm and 95 GHz passband width on a 100 ...

Improving Transmission Performance In Differential Phase Shift Keyed Systems By Use Of Lumped Nonlinear Phase Shift Compensation

  • Liu X.
  • Mckinstrie C.
  • Slusher R.
  • Wei X.

We show both analytically and numerically that significant improvement in transmission performance can be achieved in phase-shift-keying (PSK) systems by using lumped nonlinear phase shift compensation (NPSC). In a single-channel 10 Gbit/s dispersion-managed soliton based PSK transmission system, Q improvement of over 3 dB is realized by a single-stage NPSC ...

TCP/IP Performance over 3G Wireless Links with Rate and Delay Variation

  • Chan M.
  • Ramjee R.

In this paper, we comprehensively evaluate the impact of variable rate and variable delay on long-lived TCP performance. We propose a model to explain and predict TCP's throughput over a link with variable rate and/or delay. We also propose a network-based solution called Ack Regulator that mitigates the effect of ...