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Search Publications by: Anthony Kos (Fed)

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Displaying 1 - 25 of 44

Relaxation measurements of an MRI system phantom at low magnetic field strengths

May 20, 2023
Author(s)
Michele Martin, Kalina Jordanova, Anthony Kos, Stephen E. Russek, Katy Keenan, Karl Stupic
Abstract Objective Temperature controlled T 1 and T 2 relaxation times are measured on NiCl 2 and MnCl 2 solutions from the ISMRM/NIST system phantom at low magnetic field strengths of 6.5 mT, 64 mT and 550 mT. Materials and methods The T 1 and T 2 were

Distance Computation Based on Coupled Spin-Torque Oscillators: Application to Image Processing

September 1, 2020
Author(s)
Minsuk Koo, Matthew Pufall, Yong Shim, Anthony B. Kos, Gyorgy Csaba, Wolfgang Porod , William Rippard, Kaushik Roy
Recent research on nano-oscillators has shown the possibility of using a coupled-oscillator network as a core-computing primitive for non-Boolean computation. The spin-torque oscillator (STO) is an attractive candidate because it is CMOS compatible, highly

Field Compressed Sensing

January 17, 2020
Author(s)
Anthony B. Kos, Fabio C. Da Silva, Jason B. Coder, Craig W. Nelson, Grace E. Antonucci, Archita Hati
Imaging solutions based on wave scattering seek real-time performance, high dynamic range, and spatial accuracy at scales spanning from nanometers to thousands of kilometers. Compressed sensing algorithms use sparsity to reduce sample size during image

Characterization of a PXIe based low-field digital NMR spectrometer

February 25, 2017
Author(s)
Joshua R. Biller, Karl F. Stupic, Anthony B. Kos, Timothy Weilert, George Rinard, Yoshi Nakashima, John M. Moreland
A low-field nuclear magnetic resonance (NMR) instrument is an important tool for investigating a wide variety of samples under different conditions. In this paper, we describe a system constructed primarily with commercially available hardware and control

SPRITE: A modernized approach to scanning probe contact resonance imaging

January 20, 2014
Author(s)
Anthony B. Kos, Jason P. Killgore, Donna C. Hurley
We describe a system for contact resonance tracking called Scanning Probe Resonance Image Tracking Electronics (SPRITE). SPRITE can image two contact resonance frequencies simultaneously and thus can be used to acquire quantitative mechanical properties

Time Required to Injection-Lock Spin Torque Nanoscale Oscillators

October 29, 2013
Author(s)
William H. Rippard, Matthew R. Pufall, Anthony B. Kos
We have injection-locked a spin-transfer oscillator to a second-harmonic electrical input signal and measured the relative phase and amplitude of the device output as a function of DC current under steady-state conditions. The relative phase of the device

Long-Wavelength Beam Steerer Based on a Micro-Electromechanical Mirror

March 1, 2013
Author(s)
Eyal Gerecht, Anthony B. Kos
Commercially available mirrors for scanning THz beams are too large to allow high-speed THz imaging. There is a need for smaller, more agile pointing apparatus to provide THz images in seconds, not minutes or hours. We have developed a fast THz beam

Time domain measurement of phase noise in a spin torque oscillator

May 13, 2009
Author(s)
Mark W. Keller, Anthony B. Kos, Thomas J. Silva, William H. Rippard, Matthew R. Pufall
We measure phase noise from the zero crossings of the voltage vs. time waveform of a spin torque nanocontact oscillating in a vortex mode. The power spectrum of the phase noise varies with Fourier frequency f as 1/f 2, consistent with frequency

256-Channel Magnetic Imaging System

January 18, 2008
Author(s)
Fabio C. da Silva, Sean Halloran, Anthony B. Kos, David P. Pappas
We present the design and fabrication of a magentoresistive imaging system capable of measuring 256 channels simultaneously along linear ranges of 4 mm and 13 mm. The channels are interfaced by custom electronics and the images are displayed in real time

256-channel magnetic imaging system

January 15, 2008
Author(s)
Fabio C. Da Silva, Sean Halloran, Anthony B. Kos, David P. Pappas
We present the design and fabrication of a magnetoresistive imaging system capable of scanning 256 channels simultaneously along linear ranges of either 4 or 13 mm. High speed electronics read the channels and transfer the data to a computer that builds

Nanomechanical Mapping with Resonance Tracking Scanned Probe Microscope

November 23, 2007
Author(s)
Anthony B. Kos, Donna C. Hurley
We present a new digital-signal-processor-based resonance tracking system for scanned probe microscopy (SPM) imaging. The system was developed to enable quantitative imaging of mechanical properties with nanoscale spatial resolution at practical data

Experimental determination of the inhomogeneous contribution to linewidth in Permalloy films using a time-resolved magneto-optic Kerr effect microprobe

September 12, 2007
Author(s)
Michael Schneider, Thomas Gerrits, Anthony B. Kos, Thomas J. Silva
We adapted a time-resolved magneto-optic microprobe for use with the pulsed inductive microwave magnetometer apparatus, allowing us to measure the magnetization dynamics of a thin Permalloy film at micrometer and millimeter length scales under exactly the

RFID Devices and Systems in Homeland Security Applications

July 1, 2007
Author(s)
Kate Remley, Jeffrey R. Guerrieri, Dylan Williams, David R. Novotny, Anthony B. Kos, Nelson Bryner, Nader Moayeri, Michael Souryal, Kang Lee, Steven Fick
This article reports on activities being carried out by the National Institute of Standards and Technology to ensure secure, reliable use of Radio-Frequency Identification (RFID) technology in homeland security and public safety applications. These

Mapping substrate/film adhesion with contact-resonance-frequency atomic force microscopy

July 12, 2006
Author(s)
Donna C. Hurley, M Kopycinski-Muller, Eric Langlois, Anthony B. Kos, N. Barbosa
We have used contact-resonance-frequency atomic force microscopy techniques to nondestructively image variations in adhesion as a buried interface. Images were acquired on a sample containing a 20nm gold (Au) blanket film on silicon (Si) with a 1 nm

Large-angle magnetization dynamics measured by time-resolved ferromagnetic resonance

March 30, 2006
Author(s)
Thomas Gerrits, Michael Schneider, Anthony B. Kos, Thomas J. Silva
A time-resolved ferromagnetic resonance technique was used to investigate the nonlinear magnetization dynamics of a 10 nm thin Permalloy TM film in response to a sequence of large-amplitude field pulses. The magnetic field pulse sequence was set at a

Nanoscale Elastic-Property Mapping with Contact-Resonance-Frequency AFM

June 1, 2005
Author(s)
Donna C. Hurley, Anthony B. Kos, Paul Rice
We describe a dynamic atomic force microscopy (AFM) method to map the nanoscale elastic properties of surfaces, thin films, and nanostructures. Our approach is based on atomic force acoustic microscopy (AFAM) techniques previously used for quantitative