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 by: Winnie Wong-Ng (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 126 - 150 of 274

Electronic structure of Ba-Ga-Ge-Si Type I Clathrates: A Ge and Ga K-Edge Study

November 9, 2012
Author(s)
Winnie Wong-Ng, Azzam Mansour, Joshua B. Martin, George S. Nolas
XANES spectroscopy was successfully used to study changes in the density of unoccupied states for silicon substituted Ba8Ga16Ge30-xSix type I clathrates. Partial density of unoccupied states with p character is modified for both Ga and Ge upon Si

Bi2Te3 and Bi2Te3-xSx FOR THERMOELECTRIC APPLICATIONS

October 15, 2012
Author(s)
Winnie K. Wong-Ng, N D. Lowhorn, Joshua B. Martin, Peter Zavalij, Howard Joress, Qingzhen Huang, Yonggao Y. Yan, Azzam Mansour, Evans L. Thomas, Jihui Yang, Martin L. Green
The increased interest in research and development on thermoelectric materials is partly due to the need for improved efficiency in the global utilization of energy resources. Historically, Bi2Te3 occupies an important position in the thermoelectric

Carbon Storage Properties of OMS-2 Manganese Oxide

April 10, 2012
Author(s)
Lan (. Li, Eric J. Cockayne, Laura Espinal, Winnie K. Wong-Ng
Manganese oxide OMS-2 material, also known as alpha-MnO2, exhibits CO2 sorption hysteresis at pressures > 7 bar. Our experiments show that the hysteretic behavior strongly depends on time, temperature and pressure. To understand the atomic structures and

Time dependent CO2 sorption hysteresis in a one-dimensional microporous octahedral molecular sieve

April 6, 2012
Author(s)
Laura Espinal, Winnie K. Wong-Ng, Andrew J. Allen, Daniel W. Siderius, Chad R. Snyder, Eric J. Cockayne, Lan (. Li, James A. Kaduk, Anais E. Espinal, Steven L. Suib, Chun Chiu
A critical challenge in the development of novel carbon capture materials with engineered porous architectures is to understand and control the phenomenon of sorption hysteresis, whereby the path to adsorption of gas molecules by the porous host differs

Crystal Structure of the Type I Clathrate Ba8Ni4Ge42

March 30, 2012
Author(s)
Winnie K. Wong-Ng, Qingzhen Huang, Igor Levin, Joseph C. Woicik, Xun Shi, Jihui Yang, James A. Kaduk
The crystal structure of Type-I clathrate Ba8Ni4Ge42 has been determined using neutron powder diffraction, transmission electron microscopy (TEM, for possible superlattice), extended X-ray absorption fine structure measurements. Ba8Ni4Ge42 is cubic with

The 2009 Materials Science &Technology Conference & Exhibition (MS&T09)

February 29, 2012
Author(s)
Winnie Wong-Ng
The 2009 Materials Science and Technology Conference and Exhibition (MS&T09) took place at the David L. Lawrence Convention Center in Pittsburgh , Pennsylvania, from October 25-29. The Conference was the leading forum addressing structure, properties

Thermoelectric Properties and Structural Variations in Bi2Te3-xSx Crystals

February 23, 2012
Author(s)
Winnie K. Wong-Ng, Howard Joress, Joshua B. Martin, Peter Zavalij, Yonggao Y. Yan, Jihui Yang
We have successfully correlated the thermoelectric properties, structure and compositional variations of a Bi2Te3-xSx single crystal using a custom-designed, non-destructive, high-throughput Seebeck coefficient screening tool, together with a single

Structural and Thermoelectric properties of BaRCo4O7 (R=Dy, Ho, Er, Tm,Yb, and Lu)

December 6, 2011
Author(s)
Winnie K. Wong-Ng, Wenjie Xie, Yonggao Y. Yan, Guangyao Liu, James A. Kaduk, Evans L. Thomas, Terry M. Tritt
The structure and thermoelectric properties of a series of barium lanthanide cobaltites, BaRCo4O7 (R = Dy, Ho, Er, Tm,Yb, and Lu), which were prepared using the spark plasma synthesis (SPS) technique, have been investigated. The space group of these

CHEMICAL INTERACTIONS OF THE Ba2YCu3O6+x SUPERCONDUCTOR WITH COATED CONDUCTOR BUFFER LAYERS

August 30, 2011
Author(s)
Winnie K. Wong-Ng, Zhi Yang, Guangyao Liu, Qingzhen Huang, Lawrence P. Cook, Shailee P. Diwanji, Christopher E. Lucas, Mi-Hye Jang, James A. Kaduk
Continued research on high Tc superconductors has led to the promise of a wide variety of industrial applications. To implement these applications, the availability of low-cost, long-length, and high-performance superconductor wire/tape and cable is

Development of a Seebeck Coefficient Standard Reference Material (SRM)™

August 1, 2011
Author(s)
Nathan Lowhorn, Winnie Wong-Ng, John Lu, Joshua B. Martin, Martin L. Green, John E. Bonevich, Evan L. Thomas, Neil Dilley, Jeff Sharp
We have successfully developed a Seebeck coefficient Standard Reference Material (SRM™), Bi2Te3, that is essential for interlaboratory data comparison and for instrument calibration. Certification measurements were performed using a differential steady

Formation of stacking faults and their correlation with flux-pinning and critical current density for Sm-doped YBa2Cu3O7-x films

June 29, 2011
Author(s)
Winnie K. Wong-Ng, Sung H. Wee, Eliot D. Specht, Claudia Cantoni, Jonathan Zuegel, Victor Maroni, Guangyao Liu, Timothy J. Haugan, Amit Goyal
A correlation between flux-pinning characteristics and stacking faults (SFs) formed by Sm substitution on Y and Ba sites was found in Sm-doped YBCO films. It was confirmed that “223” type SFs, Y2Ba2Cu3Ox, composed of Y and O extra planes aligned parallel

APPLICATIONS OF HIGH-THROUGHPUT SCREENING TOOLS FOR THERMOELECTRIC MATERIALS

June 21, 2011
Author(s)
Winnie K. Wong-Ng, Howard L. Joress, Joshua B. Martin, Yonggao Y. Yan, Jihui Yang, Makoto Otani, Evan L. Thomas, Martin L. Green, Jason Hattrick-Simpers
The increased research and development on thermoelectric materials in recent years has been driven primarily by the need for improved efficiency in the global utilization of energy resources. To facilitate the search for new thermoelectric materials, we

Phase Equilibria, Crystal Chemistry and Thermoelectric Properties of Compounds in the Ca-Co-Zn-O System

June 21, 2011
Author(s)
Winnie K. Wong-Ng, Tana Luo, Wenjie Xie, Weihua Tang, James A. Kaduk, Qingzhen Huang, Yonggao Y. Yan, Soma Chattopadhyay
In the Ca-Co-Zn-O system, we have determined the tie-line relationships and the thermoelectric properties, solid solution limits, and structures of two low-dimensional cobaltite series, Ca3(Co, Zn)4O9 and Ca3(Co,Zn)2O6 at 885 C in air. In Ca3(Co,Zn)4O9

MSEL Sustainability Seminar Series (2009)

May 15, 2011
Author(s)
Winnie K. Wong-Ng, Kathryn L. Beers, Richard E. Ricker, Martin L. Green
An MSEL Sustainability Seminar Series took place in 2009, aimed at the following goals: (1) to introduce this important subject matter to our staff and (2) to learn and discuss the metrology needs for materials for sustainability applications. Since

Selective Adsorption of CO2 from Light Gas Mixtures Using a Structurally Dynamic Porous Coordination Polymer

April 29, 2011
Author(s)
Winnie K. Wong-Ng, Andrew J. Allen, Laura Espinal, Kristi L. Kauffman, Jeffrey T. Culp, Angela Goodman, Thomas G. Brown, Mark P. Bernardo, Russel J. Pancoast, Danielle Chirdon, Christopher Matranga
The selective adsorption of CO2 from binary mixtures of N2 and CH4 was investigated using a structurally dynamic porous coordination polymer, catena-bis(dibenzoylmethanato)-(4,4’bipyridyl)nickel (II), ‘NiDBM-Bpy’, as the separation sorbent. A third gas

Correlation of Variations in Thermoelectric and Microstructural Properties of P-type CeFe4Sb12 Melt-Spun Ribbons Using a Rapid Screening Method

April 6, 2011
Author(s)
Yonggao Y. Yan, Winnie K. Wong-Ng, James A. Kaduk, Gangjian Tan, Wenjie Xie, Martin L. Green, Xinfeng Tang
We have demonstrated the effect of gradients in both phase composition and microstructure of p-type CeFe4Sb12 melt-spun (MS) ribbons on Seebeck coefficient by a thermoelectric (TE) screening tool, in conjunction with XRD and DSC measurements. The spatial

The 2010 Materials Research Society (MRS) Fall Meeting

March 30, 2011
Author(s)
Winnie Wong-Ng
The 2010 Materials Research Society (MRS) Fall Meeting took place in the Hynes Convention Center and the Sheraton Boston Hotel, starting the weekend following the Thanksgiving Holidays from November 27 to December 3. This large-scale meeting included forty

Interactions of Ba2YCu3O6+x with SrTiO3 Substrate

February 12, 2011
Author(s)
Winnie K. Wong-Ng, Zhi Yang, James A. Kaduk, Lawrence P. Cook, Shailee P. Diwanji, Christopher E. Lucas
This paper describes the crystal chemistry and crystallography of products of the interaction of Ba2YCu3O6+x with the SrTiO3 buffer, which is a model system for coated conductors. A systematic study of the chemical interactions of Ba2YCu3O6+y and SrTiO3

A simple approach for selective crystal growth of Na8Si46 and Na24Si136

February 10, 2011
Author(s)
Winnie K. Wong-Ng, S Stefanoski, Peter Zavalij, George S. Nolas, Beekman Mathew
During the studies of structure/property relationships of thermoelectric intermetallic clathrates, we found that while single crystals for representative clathrates are readily grown using established techniques or flux synthesis, crystal growth of many

Study of Nanostructure Inclusion Effects on the Thermoelectric Behavior of Ca3Co4O9 Thin Films Grown by Pulsed Laser Deposition

February 1, 2011
Author(s)
Winnie K. Wong-Ng, Evans L. Thomas, Xueyan Song, Yonggao Y. Yan, Joshua B. Martin, Margaret Ratcliff, Paul N. Barnes
The influence of incorporating nanoparticulate additions into Ca3Co4O9 (CCO) thin films prepared by pulsed laser deposition using composite targets of CCO + BaZrO3 (BZO) on Si, LaAlO3 and Al2O3 substrates is investigated. X-ray data and high-resolution

High Temperature Seebeck Coefficient Metrology

December 22, 2010
Author(s)
Joshua B. Martin, Terry M. Tritt, Winnie K. Wong-Ng, Ctirad Uher
We present an overview of the challenges and practices of thermoelectric metrology at high temperature (300 K-1300 K). The Seebeck coefficient, when combined with thermal and electrical conductivity, is a useful property measurement for evaluating the

Phase Equilibria of the Ba-Sm-Y-Cu-O System for Coated Conductor Applications

September 8, 2010
Author(s)
Winnie K. Wong-Ng, Guangyao Liu, Zhi Yang, James A. Kaduk, Lawrence P. Cook
The complex phase relationships near the BaO-poor region of the quaternary Ba-Sm-Y-Cu-O oxide system prepared in pure air (pO2 = 22 kPa, 950 ºC) and in 0.1% O2 (pO2=100 Pa, 810 ºC) have been determined. This investigation also included the subsolidus

Recent Developments in Thermoelectric Metrology at NIST

July 10, 2010
Author(s)
Winnie K. Wong-Ng, Joshua B. Martin, Nathan Lowhorn, Makoto Otani, Evan L. Thomas, Martin L. Green, Jason Hattrick-Simpers, Yonggao Y. Yan, Thanh Tran, Jihui Yang
We have successfully developed several important thermoelectric metrologies in recent years at NIST. First, a low temperature (10 K to 390 K) Seebeck coefficient Standard Reference Material (SRM™), Bi2Te3, which is crucial for inter-laboratory data