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Displaying 5251 - 5275 of 73741

Descriptive Fractography on All-Ceramic Dental Crown Failures

October 12, 2021
Author(s)
Susanne Scherrer, Janet Quinn, George D. Quinn, HW A. Wiskott
Descriptive fractography has been applied to three dental ceramic crown failures for understanding the fracture process and assessing possible design inadequacies. In two cases, the original broken parts could be recovered for stereo and SEM analysis. In

Design and Evaluation of Large Aperture Gallium Fixed Point Blackbody

October 12, 2021
Author(s)
V B. Khromchenko, Sergey Mekhontsev, Leonard Hanssen
To complement existing water bath blackbodies which are now serving as NIST primary standard sources in the temperature range from 15 C to 75 C, a gallium fixed point blackbody has been recently built. The main objectives of the project included creating

Detection of Smoke From Microgravity Fires

October 12, 2021
Author(s)
D L. Urban, DeVon Griffin, Gary Ruff, Thomas Cleary, Jiann C. Yang, George W. Mulholland, Zeng-guang Yuan
The history and current status of spacecraft smoke detection is discussed including a review of the state of understanding of the effect of gravity on the resultant smoke particle size. The results from a spacecraft experiment (Comparative Soot Diagnostics

Determination of the Complex Modulus of a Supported Ultra-Thin Polymer Film

October 12, 2021
Author(s)
Christopher C. White, Wen-Li Wu
A novel technique to quantitatively measure the complex modulus of ultra-thin polymer films (sub micron) is described. This technique employs a new mechanical impedance expression developed from a two-layer viscoelastic media model. This result is combined

Development and Interpretation of the Security Rating Index

October 12, 2021
Author(s)
Jonathan Sylvie, Stephen R. Thomas, Sang-Hoon Lee, Robert E. Chapman
This article is a follow-on publication to Addressing Security in the Early Stages of the Project Life Cycle. It details the development and interpretation of the Security Rating Index (SRI), which provides a means of quantitatively assessing the level of

Development of a Small and Portable Absolute Gravimeter

October 12, 2021
Author(s)
A L. Vitouchkine, J E. Faller
lhgh precision (10 -9-10 -8)g absolute ballistic gravimeters (ABGs) are now being used worldwide. The ballistic method is based on the measurement of time and distance changes during the free fall of a test mass (TM) in a vacuum. The movement of the TM

Development of an Emergency Procedures Manual Database (REPMD)

October 12, 2021
Author(s)
J J. La Rosa, P Motabar, Kenneth G. Inn, H Ziegler
A Radioanalytical Emergency Procedures Manual Database (REPMD) is currently under development at NIST. Its main objective is to act as a valuable reference and guide summarizing information available from many sources. It will provide quick access to

DEVELOPMENT OF NbN TERAHERTZ HEB MIXERS COUPLED THROUGH SLOT-RING ANTENNAS.

October 12, 2021
Author(s)
Eyal Gerecht, Dazhen Gu, Xin Zhao, John Nicholson, Fernando R. Morales, Sigfrid Yngvessen
In order to improve the power coupling to Phonon-Cooled Hot Electron Bolometric (PHEB)devices, we are experimenting with a different type of antenna. The goal of the project is to eliminate the need for a beam splitter or diplexer and to couple both the

Development of NbN THz HEB Mixer Devices and Films

October 12, 2021
Author(s)
Eyal Gerecht, V. A. Bhupathiraju, John Nicholson, Dazhen Gu, Yan Zhuang, Fernando R. Morales, Xin Zhao, Ric Zannoni, Sigfrid Yngvesson
Until recently, the thin-film NbN samples used by most PHEB research groups across the world have been produced in Moscow(MSPU). We have developed a process for fabricating thin NbN films at the National Institute of Standards and Technology (NIST) in

Dielectric Function of Wurtzite GaN and AIN Thin Films

October 12, 2021
Author(s)
L X. Benedict, Eric L. Shirley, T Wethkamp, K Wilmers, C Cobet, N Esser, W Richter, M Cardona
We present measurements and calculations of the dielectric function of wurtzite GaN and AIN. Spectroscopic ellipsometry was used to determine ε (omega) of thin film samples in the energy range from 3 eV to 9.8 eV. Calculations of ε (omega) for the bulk

Displacive Phase Transition in SrTiO 3 Thin Films Grown on Si(001)

October 12, 2021
Author(s)
F S. Aguirre-Tostado, A Herrera-Gomez, Joseph Woicik, R Droopad, Z Yu, D G. Schlom, E Karapetrova, P Zschack
Polarization dependent x-ray absorption fine structure measurements performed at the Ti K edge together with x-ray diffraction have been used to study the local structure in SrTiO3 thin films grown epitaxially on Si(001). SrTiO3 layers on Si(001) are found

Dopant Location Identification in Nd 3+ -Doped TiO 2 Nanoparticles

October 12, 2021
Author(s)
W Li, A I. Frenkel, Joseph Woicik, C Ni, S I. Shah
Doping large bandgap semiconductors is typically done in order to enhance photocatalytic, photovoltaic and other chemical and optoelectronic properties. The identification of dopant position and its local environment is essential to exploring the doping
Displaying 5251 - 5275 of 73741
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