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Displaying 151 - 175 of 655

Spectrum Sensing with WLAN Access Points

January 5, 2016
Author(s)
Jason Coder, Ryan T. Jacobs, Vivian Musser
With wireless communication becoming more and more common in simple everyday devices, the available spectrum is quickly filling up and the risk of interference is increasing. This interference could be a slight nuisance to or it could be a more significant

Broadband Optical Properties of Graphene by Spectroscopic Ellipsometry

December 11, 2015
Author(s)
Wei Li, Nhan Van Nguyen, Guangjun Cheng, Angela R. Hight Walker, David J. Gundlach, Yiran Liang, boyuan Tian, Xuelei Liang, Lian-Mao Peng
The broadband (0.7 eV to 9.0 eV) optical properties of chemical-vapor-deposition (CVD) grown graphene are determined by spectroscopic ellipsometry. The optical absorption follows the fine structure constant in the energy range from 1.0 eV to 2.0 eV, but

Quantized Hall resistance in large-scale monolayer graphene

November 28, 2015
Author(s)
Yanfei Yang, Chiashain Chuang, Chieh W. Liu, Randolph Elmquist
Abstract: Graphene is an atomic-thickness carbon lattice that can be exfoliated from solid graphite or grown using high temperature processing methods on a variety of substrates. Many practical applications of large-area graphene, however, are limited by

Designing a Cyber-Physical Cloud Computing Architecture

June 2, 2015
Author(s)
Eric D. Simmon, Sulayman Sowe, Koji Zettsu
In this era of inter-connectivity where almost everybody, everything, and anything are networked, Cyber-Physical Systems (CPS) also known as the Internet of Things (IoT) have emerged as vital systems that use information systems to observe and modify the

Evaluation of Uncertainty in Temporal Waveforms of Microwave Transistors

June 1, 2015
Author(s)
Gustavo Avolio, Antonio Raffo, Jeffrey Jargon, Dominique Schreurs, Dylan Williams
This work focuses on the accuracy of nonlinear de-embedding applied to microwave transistor time-domain waveforms. The waveforms are acquired with a mixer-based Large-Signal Network Analyzer (LSNA) and are corrected at the transistor's reference planes by

Higher order perpendicular magnetic anisotropy in ultra-thin Co60Fe20B20 layers and the observation of an easy cone state.

June 1, 2015
Author(s)
Justin M. Shaw, Hans T. Nembach, Mathias A. Weiler, Martin A. Schoen, Thomas J. Silva, Jonathan Z. Sun, Daniel C. Worledge
We used broadband ferromagnetic resonance (FMR) spectroscopy to measure the second and forth order perpendicular magnetic anisotropies in Ta/ Co60Fe20B20/MgO layers over a thickness range of 0.8-5 nm. For a thickness greater than 1.0 nm, the easy axis is

Experimentally, How Does Cu TSV Diameter Influence its Stress State?

May 27, 2015
Author(s)
Chukwudi A. Okoro, Lyle E. Levine, Yaw S. Obeng, Ruqing Xu
In this work, an experimental study of the influence of Cu through-silicon via (TSV) diameter on stress build up was performed using synchrotron-based X-ray microdiffraction technique. Three Cu TSV diameters were studied; 3 µm, 5 µm and 8 µm, all of which

Rectangular-Waveguide Impedance

May 22, 2015
Author(s)
Dylan F. Williams, Jeffrey A. Jargon, Uwe Arz, Paul D. Hale
We discuss the role of the wave impedance in temporal measurements in rectangular waveguide and present a simple rule-of-thumb for estimating the difference of the temporal electric and magnetic field waveforms supported by the dominant TE10 mode. We also

Electro-thermal Simulation of 1200 V 4H-SiC MOSFET Short-Circuit SOA

May 10, 2015
Author(s)
Tam H. Duong, Jose M. Ortiz, David W. Berning, Allen R. Hefner Jr., Sei-Hyung Ryu, John W. Palmour
The purpose of this paper is to introduce a dynamic electro-thermal simulation and analysis approach for device design and short-circuit safe-operating-area (SOA) characterization using a physics-based electro-thermal Saber®* model. Model parameter

Beam broadening in transmission EBSD

March 16, 2015
Author(s)
Robert R. Keller, Katherine P. Rice, Mark Stoykovich
Transmission electron backscatter diffraction (t-EBSD), also known as transmission electron forward scatter diffraction (t-EFSD) or transmission Kikuchi diffraction in the SEM (TKD-SEM), can provide significant improvements in spatial resolution over

Widebend CTL cell to measure operating range of UHF RFID

March 5, 2015
Author(s)
Jehoon Yun, YongChae Jeong, David R. Novotny, Jeffrey R. Guerrieri
A wideband coupled transmission line (CTL) cell to measure the operating range of an UHF RFID (ORUR) is presented. Also, an ORUR test system is proposed to increase the isolation to more than 55 dB. It is shown that the ORUR measured by this proposed cell

Parameter Estimation and Uncertainty Evaluation in a Low Rician K-Factor Reverberation-Chamber Environment

October 15, 2014
Author(s)
Chih-Ming Wang, Catherine A. Remley, Ansgar T. Kirk, Ryan J. Pirkl, Christopher L. Holloway, Dylan F. Williams, Paul D. Hale
In this paper we study statistical methods for estimating the Rician K-factor when this parameter is small. A fiducial approach for making statistical inference on the K-factor is discussed. The approach requires a Monte Carlo method to compute the

NIST Framework and Roadmap for Smart Grid Interoperability Standards, Release 3.0

October 1, 2014
Author(s)
Chris Greer, David A. Wollman, Dean Prochaska, Paul A. Boynton, Jeffrey A. Mazer, Cuong Nguyen, Gerald FitzPatrick, Thomas L. Nelson, Galen H. Koepke, Allen R. Hefner Jr., Victoria Yan Pillitteri, Tanya L. Brewer, Nada T. Golmie, David H. Su, Allan C. Eustis, David Holmberg, Steven T. Bushby
Section 1305 of the Energy Independence and Security Act (EISA) of 2007 (Pub. L. 110-140) directs NIST ‘‘to coordinate the development of a framework that includes protocols and model standards for information management to achieve interoperability of

Physics-based Electro-thermal Saber Model and Parameter Extraction for High-Voltage SiC Buffer IGBTs

September 15, 2014
Author(s)
Tam H. Duong, Allen R. Hefner Jr., Jose M. Ortiz, Sei-Hyung Ryu , Edward VanBrunt, Lin Cheng, Scott Allen, John W. Palmour
The purpose of this paper is to present a physics-based electro-thermal Saber model and parameter extraction sequence for high-voltage SiC buffer layer n-channel insulated gate bipolar transistors (IGBTs). This model was developed by modifying and

A 100 Tohm Guarded Hamon Transfer Standard

August 24, 2014
Author(s)
Dean G. Jarrett, Edward O'Brien, Marlin E. Kraft
Guarded Hamon transfer standards are used at NIST for scaling to high resistance levels. An improved design for a guarded Hamon transfer standard in the range from 1 TΩ to 100 TΩ is described. Measurements taken to select the primary and guard resistor

Photonic-assisted Endoscopic Analysis of Guided W-band Pulses

August 24, 2014
Author(s)
Jeffrey A. Jargon, DongJoon Lee, JaeYong Kwon
We present a photonic-assisted time-domain measurement technique for exploring millimeter-wave propagation through a W-band waveguide. The electric fields, guided inside a rectangular waveguide, are sampled using a sub-millimeter-scale electro-optic probe
Displaying 151 - 175 of 655