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Search Publications by: Li-Anne Liew (Fed)

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Displaying 1 - 25 of 25

Evaluation of a Modified Void Descriptor Function to Uniquely Characterize Pore Networks and Predict Fracture Location in Additively Manufactured Metals

November 15, 2021
Author(s)
Dillon Watring, Jake Benzing, Orion Kafka, Li-Anne Liew, Newell Moser, John Erickson, Nik Hrabe, Ashley Spear
Variations in additive manufacturing (AM) processing parameters can lead to variations in porosity, making it challenging to predict pore- or void-sensitive mechanical response in AM metals. A recently developed pore metric, the void descriptor function

Experimental study of shear and tensile properties of LIGA Ni-Fe and Ni-Co alloys at quasi-static and intermediate strain rates

April 1, 2021
Author(s)
Li-Anne Liew, David T. Read, May Martin, Todd R. Christenson, Peter E. Bradley, Nicholas Barbosa, Frank W. DelRio, John T. Geaney, Jeffrey Smyth
We report the in-plane shear properties, to fracture, of 200 um-thick LIGA nanocrystalline Ni- 10%Fe and micrograined Ni-10%Co. Planar simple shear specimens were designed, fabricated and pulled to fracture using a miniature commercial tension test stage

Elastic-plastic properties of mesoscale electrodeposited LIGA nickel alloy films: microscopy and mechanics

November 22, 2020
Author(s)
Li-Anne Liew, David T. Read, May Martin, Frank W. DelRio, Peter E. Bradley, Nicholas Barbosa, Todd R. Christenson, John T. Geaney
The elastic-plastic properties of mesoscale electrodeposited LIGA Ni alloy specimens are investigated as a function of specimen size, strain rate, and material composition. Two material compositions are studied: a high-strength fine-grained Ni-Fe alloy and

Dominant factors for fracture at the micro-scale in electrodeposited nickel alloys

August 1, 2020
Author(s)
May L. Martin, Li-Anne Liew, David T. Read, Todd Christensen, Frank W. DelRio, John Geaney
Two different LIGA electrodeposited nickel alloys displayed distinct fracture modes after meso- scale tensile testing. The Ni-Co alloy failed in a ductile manner, while the Ni-Fe alloy failed in a more brittle-appearing manner. Various factors affecting

MEMS Device for Fatigue Testing of 25 mm Thick Aluminum Specimens

June 13, 2013
Author(s)
Li-Anne Liew, David T. Read, Nicholas Barbosa
We report the development and demonstration of a MEMS test instrument to perform fatigue testing on 25 µm thick aluminum 1145 H19 foil. Both the foil material and the specimen fabrication were obtained from commercial sources, separate from the fabrication

MEMS-based universal fatigue test technique

August 22, 2012
Author(s)
Li-Anne Liew, David T. Read, Nicholas Barbosa
We have developed a MEMS (micro electro mechanical systems) -based method for fatigue testing of micro- to millimeter-sized specimens of any material (hence ‘universal’). The miniature, re- usable, stand-alone fatigue test frame is fabricated as a single

A thickness-shear MEMS resonator employing electromechanical transduction through a coplanar waveguide

May 21, 2012
Author(s)
Ward L. Johnson, Thomas M. Wallis, Pavel Kabos, Eduard Rocas, Juan C. Collado Gomez, Li-Anne Liew, Albert Davydov, Alivia Plankis, Paul R. Heyliger
The design, modeling, fabrication, and characterization of a vibrationally trapped thickness-shear MEMS resonator is presented. This device is intended to avoid various limitations of flexural MEMS resonators, including nonlinearity, clamping losses

Chip scale atomic magnetometers

April 19, 2006
Author(s)
John M. Moreland, John Kitching, Peter D. Schwindt, Svenja A. Knappe, Li-Anne Liew, V Shah, V Gerginov, Ying-Ju Wang, Leo W. Hollberg
We are developing a new class of sensors based on atoms confined in micro-fabricated enclosures. Recent work at the National Institute of Standards and Technology (NIST) has lead to a prototype chip scale atomic clock (CSAC) with remarkable operating

Chip-Scale Atomic Frequency References: Fabrication and Performance

December 1, 2005
Author(s)
John Kitching, Svenja A. Knappe, Li-Anne Liew, John M. Moreland, Hugh Robinson, Peter D. Schwindt, V Shah, V Gerginov, Leo W. Hollberg
The physics package for a chip-scale atomic frequency reference was constructed and tested. The device has a total volume of 9.5 mm 3 , dissipates 75 mW of electrical power at an ambient temperature of 45 °C and has a short-term fractional frequency

Microfabricated Atomic Frequency References

August 1, 2005
Author(s)
John Kitching, Svenja A. Knappe, Li-Anne Liew, John M. Moreland, Peter D. Schwindt, V Shah, V Gerginov, Leo W. Hollberg
Using microfabrication processes, we have been able to construct physics packages for vapour cell atomic frequency references 100x smaller than previously existing versions, with a corresponding reduction in power consumption. In addition, the devices

Microfabricated Atomic Clocks

January 1, 2005
Author(s)
John E. Kitching, Svenja A. Knappe, Li-Anne Liew, P Schwindt, V Shah, John M. Moreland, Leo W. Hollberg
We describe recent progress at NIST in the development of compact, low-power atomic frequency references based on microfabrication processes. The physics packages of these frequency references have a volume near 10 cm 3 , require less than 100 mW of power

Chip-Scale Atomic Magnetometers

December 1, 2004
Author(s)
P Schwindt, Svenja A. Knappe, V Shah, Leo W. Hollberg, John E. Kitching, Li-Anne Liew, John M. Moreland
Using the techniques of micro-electro-mechanical systems, we have constructed a small, low-power magnetic sensor based on alkali atoms. We use a coherent population trapping resonance to probe the interaction of the atoms' magnetic moment with a magnetic

Microfabricated Atomic Frequency References

August 1, 2004
Author(s)
Svenja A. Knappe, P Schwindt, V Shah, Leo W. Hollberg, John E. Kitching, Li-Anne Liew, John M. Moreland
We describe a design for a microfabricated atomic frequency reference with a volume of several cubic millimetres and a power dissipation in the range ot tens of milliwatts. It is anticipated that this frequency reference will be capable of achieving a

Microfabricated alkali atom vapor cells

April 5, 2004
Author(s)
Li-Anne Liew, Svenja A. Knappe, John M. Moreland, Hugh Robinson, David C. Larbalestier, John Kitching
We describe the fabrication of chip-sized alkali atom vapor cells using silicon micromachining and anodic bonding technology. Such cells may find use in highly miniaturized atomic frequency references or magnetometers. The cells consist of cavities etched

Micromachined Alkali Atom Vapor Cells for Chip-Scale Atomic Clocks

January 30, 2004
Author(s)
Li-Anne Liew, Svenja A. Knappe, John M. Moreland, Hugh Robinson, Leo W. Hollberg, John Kitching
This paper describes the fabrication of chip-sized alkali atom vapor cells, for use in highly miniaturized atomic frequency references, using silicon micromachining and anodic bonding technology. The cells consist of silicon cavities with internal volume

Atomic vapor cells for miniature frequency references

May 8, 2003
Author(s)
Svenja A. Knappe, V. Velichansky, Hugh Robinson, Li-Anne Liew, John M. Moreland, John Kitching, Leo W. Hollberg
We report on the fabrication of millimeter-sized vapor cells and their performance on atomic clocks based on coherent population trapping (CPT). We discuss two fabrication techniques, the first one based on hollow-core pyrex fibers, fused with a CO 2 laser