U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications

NIST Authors in Bold

Displaying 601 - 625 of 2122

Perovskite-Related ReO 3 -Type Structures

March 1, 2020
Author(s)
Hayden A Evans, Yue Wu, Ram Seshadri, Anthony K. Cheetham
ReO 3-type structures can be described as ABX 3 perovskites in which the A-cation site is unoccupied. They therefore have the general composition BX 3, where B is normally a cation and X is a bridging anion. The chemical diversity of such structures is

Enhanced Dynamics of Confined Polymers near the Immiscible Polymer-Polymer Interface: Neutron Reflectivity Studies

February 18, 2020
Author(s)
Kyoung-Il Jo, Younghoon Oh, Bong June Sung, Tae-Ho Kim, Min Seop Um, Woo Jin Choi, Joona Bang, Guangcui Yuan, Sushil K. Satija, Jaseung Koo
For polymer-blend films, local dynamics in confined polymer domains tend to differ from the bulk due to significant contributions from the polymer-polymer interface. Herein, we investigated the diffusion dynamics of entangled polymer thin films confined

Metal adsorbate interactions and the convergence of density functional calculations

February 10, 2020
Author(s)
Christoph Rohmann, Maicol A. Ochoa, Michael P. Zwolak
The adsorption of metal atoms on nanostructures, such as graphene and nanotubes, plays an important role in catalysis, electronic doping, and tuning material properties. Quantum chemical calculations permit the investigation of this process to discover

Dynamic Arrest of Adhesive Hard Rod Dispersions

February 7, 2020
Author(s)
Ryan P Murphy, Harold Wickes Hatch, Nathan NMN Mahynski, Vincent K. Shen, Norman J. Wagner
Dynamic arrest transitions of model, thermoreversible dispersions of adhesive hard rods are measured as a function of absolute temperature Τ = 15 -40 °C, aspect ration L/D{approximately equal}3-7, and volume fraction φ0.1-0.5. The critical gel temperature

Dynamic Heterogeneity and Collective Motion in Star Polymer Melts

February 4, 2020
Author(s)
Jack F. Douglas, Jinpeng Fan, Hamed Emamy, Francis W. Starr, Alexandros Chremos
While glass formation of linear chain polymers has been widely explored, comparatively little is known about glass formation in star polymer melts. We study the segmental dynamics of star polymers via molecular dynamics simulations and contrast the

Alignment of Worm-like Micelles at Intermediate and High Shear Rates

February 1, 2020
Author(s)
Brisa Arenas-Gomez, Cristina Garza, Yun Liu, Rolando Castillo
Hypothesis. Rheology combined with Small Angle Neutron Scattering (Rheo-SANS) can determine the local structural order in Worm-like Micelle (WLM) solutions, when the shear rate increases beyond the ending of the gradient shear banding, where the micellar

Emergent Electric Field Control of Phase Transformation in Oxide Superlattices

February 1, 2020
Author(s)
Di Yi, Yujia Wang, Olaf M. J. van t'Erve, Liubin Xu, Hongtao Yuan, Michael J. Veit, Purnima P. Balakrishnan, Yongseong Choi, Alpha T. N'Diaye, Padraic Shafer, E. Arenholz, Alexander Grutter, Haixuan Xu, Pu Yu, Berend T. Jonker, Yuri Suzuki
Electric fields have been shown to transform materials with respect to their structure and properties, thus enabling many applications ranging from batteries to spintronics. Recently electrolytic gating, which can generate large electric fields and voltage

Pressure-Thresholded Response in Cylindrically Shocked Cyclotrimethylene Trinitramine (RDX)

February 1, 2020
Author(s)
Leora E. Dresselhaus-Cooper, Dmitro Martynowych, Fan Zhang, Charlene Tsay, Jan Ilavsky, SuYin Wang, Yu-Sheng Chen, Lara Leininger, Keith A. Nelson
We demonstrate a strongly thresholded response in cyclotrimethylene trinitramine (RDX) that is cylindrically shocked using a novel waveguide geometry. Using ultrafast single-shot multi-frame imaging, we demonstrate that a 100-μm diameter single crystal of

Reversed Ethane/Ethylene Adsorption in Metal-Organic Frameworks via Introduction of Oxygen

February 1, 2020
Author(s)
Ling Yang, Wei Zhou, Hao Li, Ali Alsalme, Litao Jia, Jinping Li, Libo Li, Banglin Chen
Separation of ethane from ethylene is a very important but challenging process in the petrochemical industry. Finding an alternative method would reduce the energy needed to make the 170 million tons of ethylene manufactured worldwide each year. Adsorptive

Influence of Polymer Topology on Crystallization in Thin Films

January 22, 2020
Author(s)
Jack F. Douglas, Andrea Giuntoli, Alexandros Chremos
We investigate how varying molecular topology of polymers influences crystallization in thin polymer films. In particular, we simulate linear and star polymers having a progressively increasing number of arms (f ≤ 16) for fixed molecular mass of polymer

THE CERTIFICATION OF STANDARD REFERENCE MATERIAL 660C FOR POWDER DIFFRACTION

January 15, 2020
Author(s)
David R. Black, Marcus H. Mendenhall, Albert Henins, James J. Filliben, James P. Cline
The National Institute of Standards and Technology (NIST) certifies a suite of Standard Reference Materials (SRMs) to evaluate specific aspects of instrument performance of both x-ray and neutron powder diffractometers. This report describes SRM 660c, the

Observation of an isomerizing double-well quantum system in the condensed phase

January 10, 2020
Author(s)
Varun Verma, Jascha A. Lau, Arnab Choudhury, Li Chen, Dirk Schwarzer, Alec M. Wodtke
Molecules are quantum objects; therefore, isomerization fundamentally involves quantum states bound within a molecular potential energy function with multiple minima. For isolated gas-phase molecules, eigenstates well above the isomerization saddle points

The impact of the metal interface on the stability and quality of a therapeutic fusion protein

January 9, 2020
Author(s)
Adrian P. Defante, Steven D. Hudson, Cavan K. Kalonia, Emma Keegan, Steven Bishop, Paul Santacroce, Satish Hasige
Subvisible particle formation which occurs after the sterile filtration step of the fill/finish process is challenge that may occur during the development of biotherapeutics with complex molecular structures. Here, we show that a stainless-steel pump head

Selective Ethane/Ethylene Separation in a Robust Microporous Hydrogen-Bonded Organic Framework

January 8, 2020
Author(s)
Xu Zhang, Libo Li, Jia-Xin Wang, Hui-Min Wen, Rajamani Krishna, Hui Wu, Wei Zhou, Zhong-Ning Chen, Bin Li, Guodong Qian, Banglin Chen
The separation of ethane (C 2H 6) from ethylene (C 2H 4) is of prime importance in the production of polymergrade C 2H 4 for industrial manufacturing. It is very challenging and still remains unexploited to fully realize efficient C 2H 6/C 2H 4 separation

Dysprosium Iron Garnet Thin Films with Perpendicular Magnetic Anisotropy on Silicon

January 1, 2020
Author(s)
Jackson J. Bauer, Ethan R. Rosenberg, Subhajit Kundu, K. Andre Mkhoyan, Patrick Quarterman, Alexander Grutter, Brian Kirby, Julie Borchers, Caroline A. Ross
Magnetic insulators, such as the rare-earth iron garnets, are promising materials for energy-efficient spintronic memory and logic devices, and their anisotropy, magnetization and other properties can be tuned over a wide range through selection of the

Enhanced Conductivity via Homopolymer-Rich Pathways in Block Polymer-Blended Electrolytes

December 24, 2019
Author(s)
Melody A. Morris, Seung Hyun Sung, Priyanka M. Ketkar, Joseph Dura, Ryan Nieuwendaal, III Epps
The optimization of ionic conductivity and lithium-ion battery stability can be achieved by independently tuning the ion transport and mechanical robustness of block polymer (BP) electrolytes. However, the ionic conductivity of BP electrolytes is
Displaying 601 - 625 of 2122